Science.gov

Sample records for porous polymeric scaffolds

  1. Bioinspired Strong and Highly Porous Glass Scaffolds

    PubMed Central

    Saiz, Eduardo; Tomsia, Antoni P.

    2011-01-01

    The quest for more efficient energy-related technologies is driving the development of porous and high-performance structural materials with exceptional mechanical strength. Natural materials achieve their strength through complex hierarchical designs and anisotropic structures that are extremely difficult to replicate synthetically. We emulate nature’s design by direct-ink-write assembling of glass scaffolds with a periodic pattern, and controlled sintering of the filaments into anisotropic constructs similar to biological materials. The final product is a porous glass scaffold with a compressive strength (136 MPa) comparable to that of cortical bone and a porosity (60%) comparable to that of trabecular bone. The strength of this porous glass scaffold is ~100 times that of polymer scaffolds and 4–5 times that of ceramic and glass scaffolds with comparable porosities reported elsewhere. The ability to create both porous and strong structures opens a new avenue for fabricating scaffolds for a broad array of applications, including tissue engineering, filtration, lightweight composites, and catalyst support. PMID:21544222

  2. A review: fabrication of porous polyurethane scaffolds.

    PubMed

    Janik, H; Marzec, M

    2015-03-01

    The aim of tissue engineering is the fabrication of three-dimensional scaffolds that can be used for the reconstruction and regeneration of damaged or deformed tissues and organs. A wide variety of techniques have been developed to create either fibrous or porous scaffolds from polymers, metals, composite materials and ceramics. However, the most promising materials are biodegradable polymers due to their comprehensive mechanical properties, ability to control the rate of degradation and similarities to natural tissue structures. Polyurethanes (PUs) are attractive candidates for scaffold fabrication, since they are biocompatible, and have excellent mechanical properties and mechanical flexibility. PU can be applied to various methods of porous scaffold fabrication, among which are solvent casting/particulate leaching, thermally induced phase separation, gas foaming, emulsion freeze-drying and melt moulding. Scaffold properties obtained by these techniques, including pore size, interconnectivity and total porosity, all depend on the thermal processing parameters, and the porogen agent and solvents used. In this review, various polyurethane systems for scaffolds are discussed, as well as methods of fabrication, including the latest developments, and their advantages and disadvantages. PMID:25579961

  3. Porous ceramic scaffolds with complex architectures

    SciTech Connect

    Saiz, Eduardo; Munch, Etienne; Franco, Jaime; Deville, Sylvain; Hunger, Phillip; Saiz, Eduardo; Tomsia, Antoni P.

    2008-03-15

    This work compares two novel techniques for the fabrication of ceramic scaffolds for bone tissue engineering with complex porosity: robocasting and freeze casting. Both techniques are based on the preparation of concentrated ceramic suspensions with suitable properties for the process. In robocasting, the computer-guided deposition of the suspensions is used to build porous materials with designed three dimensional (3-D) geometries and microstructures. Freeze casting uses ice crystals as a template to form porous lamellar ceramic materials. Preliminary results on the compressive strengths of the materials are also reported.

  4. Exploiting novel sterilization techniques for porous polyurethane scaffolds.

    PubMed

    Bertoldi, Serena; Farè, Silvia; Haugen, Håvard Jostein; Tanzi, Maria Cristina

    2015-05-01

    Porous polyurethane (PU) structures raise increasing interest as scaffolds in tissue engineering applications. Understanding the effects of sterilization on their properties is mandatory to assess their potential use in the clinical practice. The aim of this work is the evaluation of the effects of two innovative sterilization techniques (i.e. plasma, Sterrad(®) system, and ozone) on the morphological, chemico-physical and mechanical properties of a PU foam synthesized by gas foaming, using water as expanding agent. In addition, possible toxic effects of the sterilization were evaluated by in vitro cytotoxicity tests. Plasma sterilization did not affect the morphological and mechanical properties of the PU foam, but caused at some extent degradative phenomena, as detected by infrared spectroscopy. Ozone sterilization had a major effect on foam morphology, causing the formation of new small pores, and stronger degradation and oxidation on the structure of the material. These modifications affected the mechanical properties of the sterilized PU foam too. Even though, no cytotoxic effects were observed after both plasma and ozone sterilization, as confirmed by the good values of cell viability assessed by Alamar Blue assay. The results here obtained can help in understanding the effects of sterilization procedures on porous polymeric scaffolds, and how the scaffold morphology, in particular porosity, can influence the effects of sterilization, and viceversa. PMID:25893387

  5. Rapid Engineering of Three-Dimensional, Multicellular Tissues With Polymeric Scaffolds

    NASA Technical Reports Server (NTRS)

    Gonda, Steve R.; Jordan, Jacqueline; Fraga, Denise N.

    2007-01-01

    A process has been developed for the rapid tissue engineering of multicellular-tissue-equivalent assemblies by the controlled enzymatic degradation of polymeric beads in a low-fluid-shear bioreactor. In this process, the porous polymeric beads serve as temporary scaffolds to support the assemblies of cells in a tissuelike 3D configuration during the critical initial growth phases of attachment of anchorage-dependent cells, aggregation of the cells, and formation of a 3D extracellular matrix. Once the cells are assembled into a 3D array and enmeshed in a structural supportive 3D extracellular matrix (ECM), the polymeric scaffolds can be degraded in the low-fluid-shear environment of the NASA-designed bioreactor. The natural 3D tissuelike assembly, devoid of any artificial support structure, is maintained in the low-shear bioreactor environment by the newly formed natural cellular/ECM. The elimination of the artificial scaffold allows normal tissue structure and function.

  6. Living Bacterial Sacrificial Porogens to Engineer Decellularized Porous Scaffolds

    E-print Network

    Xu, Feng

    Decellularization and cellularization of organs have emerged as disruptive methods in tissue engineering and regenerative medicine. Porous hydrogel scaffolds have widespread applications in tissue engineering, regenerative ...

  7. Thermoforming techniques for manufacturing porous scaffolds for application in 3D cell cultivation.

    PubMed

    Borowiec, Justyna; Hampl, Jörg; Gebinoga, Michael; Elsarnagawy, Tarek; Elnakady, Yasser A; Fouad, Hassan; Almajhadi, Fahd; Fernekorn, Uta; Weise, Frank; Singh, Sukhdeep; Elsarnagawy, Dief; Schober, Andreas

    2015-04-01

    Within the scientific community, there is an increasing demand to apply advanced cell cultivation substrates with increased physiological functionalities for studying spatially defined cellular interactions. Porous polymeric scaffolds are utilized for mimicking an organ-like structure or engineering complex tissues and have become a key element for three-dimensional (3D) cell cultivation in the meantime. As a consequence, efficient 3D scaffold fabrication methods play an important role in modern biotechnology. Here, we present a novel thermoforming procedure for manufacturing porous 3D scaffolds from permeable materials. We address the issue of precise thermoforming of porous polymer foils by using multilayer polymer thermoforming technology. This technology offers a new method for structuring porous polymer foils that are otherwise available for non-porous polymers only. We successfully manufactured 3D scaffolds from solvent casted and phase separated polylactic acid (PLA) foils and investigated their biocompatibility and basic cellular performance. The HepG2 cell culture in PLA scaffold has shown enhanced albumin secretion rate in comparison to a previously reported polycarbonate based scaffold with similar geometry. PMID:25686978

  8. Flow-Induced Stress Distribution in Porous Scaffolds

    NASA Astrophysics Data System (ADS)

    Papavassiliou, Dimitrios; Voronov, Roman; Vangordon, Samuel; Sikavitsas, Vassilios

    2010-11-01

    Flow-induced stresses help the differentiation and proliferation of mesenchymal cells cultured in porous scaffolds within perfusion bioreactors. The distribution of stresses in a scaffold is thus important for understanding the tissue growth process in such reactors. Computational results for flow through Poly-L-Lactic Acid porous scaffolds that have been produced with salt-leaching techniques, and for scaffolds that have been constructed with nonwoven fibers, indicate that the probability density function (pdf) of the wall stress, when normalized with the mean and the standard deviation of the pdf, appears to follow a single type of pdf. The scaffolds were imaged with micro-CT and the simulations were run with lattice Boltzmann methods. The parameters of the distribution can be obtained using Darcy's law and the Blake-Kozeny-Carman equation. Experimental results available in the literature appear to corroborate the computational findings, leading to the conclusion that stresses in high-porosity porous materials follow a single distribution.

  9. Porous Biodegradable Metals for Hard Tissue Scaffolds: A Review

    PubMed Central

    Yusop, A. H.; Bakir, A. A.; Shaharom, N. A.; Abdul Kadir, M. R.; Hermawan, H.

    2012-01-01

    Scaffolds have been utilized in tissue regeneration to facilitate the formation and maturation of new tissues or organs where a balance between temporary mechanical support and mass transport (degradation and cell growth) is ideally achieved. Polymers have been widely chosen as tissue scaffolding material having a good combination of biodegradability, biocompatibility, and porous structure. Metals that can degrade in physiological environment, namely, biodegradable metals, are proposed as potential materials for hard tissue scaffolding where biodegradable polymers are often considered as having poor mechanical properties. Biodegradable metal scaffolds have showed interesting mechanical property that was close to that of human bone with tailored degradation behaviour. The current promising fabrication technique for making scaffolds, such as computation-aided solid free-form method, can be easily applied to metals. With further optimization in topologically ordered porosity design exploiting material property and fabrication technique, porous biodegradable metals could be the potential materials for making hard tissue scaffolds. PMID:22919393

  10. Novel biodegradable porous scaffold applied to skin regeneration.

    PubMed

    Wang, Hui-Min; Chou, Yi-Ting; Wen, Zhi-Hong; Wang, Chau-Zen; Wang, Zhao-Ren; Chen, Chun-Hong; Ho, Mei-Ling

    2013-01-01

    Skin wound healing is an important lifesaving issue for massive lesions. A novel porous scaffold with collagen, hyaluronic acid and gelatin was developed for skin wound repair. The swelling ratio of this developed scaffold was assayed by water absorption capacity and showed a value of over 20 g water/g dried scaffold. The scaffold was then degraded in time- and dose-dependent manners by three enzymes: lysozyme, hyaluronidase and collagenase I. The average pore diameter of the scaffold was 132.5±8.4 µm measured from SEM images. With human skin cells growing for 7 days, the SEM images showed surface fractures on the scaffold due to enzymatic digestion, indicating the biodegradable properties of this scaffold. To simulate skin distribution, the human epidermal keratinocytes, melanocytes and dermal fibroblasts were seeded on the porous scaffold and the cross-section immunofluorescent staining demonstrated normal human skin layer distributions. The collagen amount was also quantified after skin cells seeding and presented an amount 50% higher than those seeded on culture wells. The in vivo histological results showed that the scaffold ameliorated wound healing, including decreasing neutrophil infiltrates and thickening newly generated skin compared to the group without treatments. PMID:23762223

  11. Novel Biodegradable Porous Scaffold Applied to Skin Regeneration

    PubMed Central

    Wang, Hui-Min; Chou, Yi-Ting; Wen, Zhi-Hong; Wang, Zhao-Ren; Chen, Chun-Hong; Ho, Mei-Ling

    2013-01-01

    Skin wound healing is an important lifesaving issue for massive lesions. A novel porous scaffold with collagen, hyaluronic acid and gelatin was developed for skin wound repair. The swelling ratio of this developed scaffold was assayed by water absorption capacity and showed a value of over 20 g water/g dried scaffold. The scaffold was then degraded in time- and dose-dependent manners by three enzymes: lysozyme, hyaluronidase and collagenase I. The average pore diameter of the scaffold was 132.5±8.4 µm measured from SEM images. With human skin cells growing for 7 days, the SEM images showed surface fractures on the scaffold due to enzymatic digestion, indicating the biodegradable properties of this scaffold. To simulate skin distribution, the human epidermal keratinocytes, melanocytes and dermal fibroblasts were seeded on the porous scaffold and the cross-section immunofluorescent staining demonstrated normal human skin layer distributions. The collagen amount was also quantified after skin cells seeding and presented an amount 50% higher than those seeded on culture wells. The in vivo histological results showed that the scaffold ameliorated wound healing, including decreasing neutrophil infiltrates and thickening newly generated skin compared to the group without treatments. PMID:23762223

  12. A thermophone on porous polymeric substrate

    NASA Astrophysics Data System (ADS)

    Chitnis, G.; Kim, A.; Song, S. H.; Jessop, A. M.; Bolton, J. S.; Ziaie, B.

    2012-07-01

    In this Letter, we present a simple, low-temperature method for fabricating a wide-band (>80 kHz) thermo-acoustic sound generator on a porous polymeric substrate. We were able to achieve up to 80 dB of sound pressure level with an input power of 0.511 W. No significant surface temperature increase was observed in the device even at an input power level of 2.5 W. Wide-band ultrasonic performance, simplicity of structure, and scalability of the fabrication process make this device suitable for many ranging and imaging applications.

  13. Design of a bioresorbable polymeric scaffold for osteoblast culture

    NASA Astrophysics Data System (ADS)

    Ditaranto, Vincent M., Jr.

    Bioresorbable polymeric scaffolds were designed for the purpose of growing rat osteosarcoma cells (ROS 17/2.8) using the compression molding method. The material used in the construction of the scaffolds was a mixture of polycaprolactone (PCL), Hydroxyapatite (HA), Glycerin (GL) and salt (NaCl) for porosity. The concentration of the several materials utilized, was determined by volume. Past research at the University of Massachusetts Lowell (UML) has successfully utilized the compression molding method for the construction of scaffolds, but was unable to accomplish the goal of long term cell survival and complete cellular proliferation throughout a three dimensional scaffold. This research investigated various concentrations of the materials and molding temperatures used for the manufacture of scaffolds in order to improve the scaffold design and address those issues. The design of the scaffold using the compression molding process is detailed in the Method and Materials section of this thesis. The porogen (salt) used for porosity was suspected as a possible source of contamination causing cell apoptosis in past studies. This research addressed the issues for cell survival and proliferation throughout a three dimensional scaffold. The leaching of the salt was one major design modification. This research successfully used ultrasonic leaching in addition to the passive method. Prior to cell culture, the scaffolds were irradiated to 2.75 Mrad, with cobalt-60 gamma radionuclide. The tissue culture consisted of two trials: (1) cell culture in scaffolds cleaned with passive leaching; (2) cell culture with scaffolds cleaned with ultrasonic leaching. Cell survival and proliferation was accomplished only with the addition of ultrasonic leaching of the scaffolds. Analysis of the scaffolds included Scanning Electron Microscopy (SEM), Nikon light microscopy and x-ray mapping of the calcium, sodium and chloride ion distribution. The cells were analyzed by Environmental Scanning Electron Microscopy (ESEM) and Nikon light microscopy. The high magnification of ESEM up to 60,000 x revealed an unexpected discovery. The osteoblasts appeared to be remodeling the PCL scaffold shown in the last two figures of this research.

  14. Bioactive polymeric-ceramic hybrid 3D scaffold for application in bone tissue regeneration.

    PubMed

    Torres, A L; Gaspar, V M; Serra, I R; Diogo, G S; Fradique, R; Silva, A P; Correia, I J

    2013-10-01

    The regeneration of large bone defects remains a challenging scenario from a therapeutic point of view. In fact, the currently available bone substitutes are often limited by poor tissue integration and severe host inflammatory responses, which eventually lead to surgical removal. In an attempt to address these issues, herein we evaluated the importance of alginate incorporation in the production of improved and tunable ?-tricalcium phosphate (?-TCP) and hydroxyapatite (HA) three-dimensional (3D) porous scaffolds to be used as temporary templates for bone regeneration. Different bioceramic combinations were tested in order to investigate optimal scaffold architectures. Additionally, 3D ?-TCP/HA vacuum-coated with alginate, presented improved compressive strength, fracture toughness and Young's modulus, to values similar to those of native bone. The hybrid 3D polymeric-bioceramic scaffolds also supported osteoblast adhesion, maturation and proliferation, as demonstrated by fluorescence microscopy. To the best of our knowledge this is the first time that a 3D scaffold produced with this combination of biomaterials is described. Altogether, our results emphasize that this hybrid scaffold presents promising characteristics for its future application in bone regeneration. PMID:23910366

  15. Graphene-based electroresponsive scaffolds as polymeric implants for on-demand drug delivery.

    PubMed

    Servant, Ania; Leon, Veronica; Jasim, Dhifaf; Methven, Laura; Limousin, Patricia; Fernandez-Pacheco, Ester Vazquez; Prato, Maurizio; Kostarelos, Kostas

    2014-08-01

    Stimuli-responsive biomaterials have attracted significant attention in the field of polymeric implants designed as active scaffolds for on-demand drug delivery. Conventional porous scaffolds suffer from drawbacks such as molecular diffusion and material degradation, allowing in most cases only a zero-order drug release profile. The possibility of using external stimulation to trigger drug release is particularly enticing. In this paper, the fabrication of previously unreported graphene hydrogel hybrid electro-active scaffolds capable of controlled small molecule release is presented. Pristine ball-milled graphene sheets are incorporated into a three dimensional macroporous hydrogel matrix to obtain hybrid gels with enhanced mechanical, electrical, and thermal properties. These electroactive scaffolds demonstrate controlled drug release in a pulsatile fashion upon the ON/OFF application of low electrical voltages, at low graphene concentrations (0.2 mg mL(-1) ) and by maintaining their structural integrity. Moreover, the in vivo performance of these electroactive scaffolds to release drug molecules without any "resistive heating" is demonstrated. In this study, an illustration of how the heat dissipating properties of graphene can provide significant and previously unreported advantages in the design of electroresponsive hydrogels, able to maintain optimal functionality by overcoming adverse effects due to unwanted heating, is offered. PMID:24799416

  16. Laser 3D printing with sub-microscale resolution of porous elastomeric scaffolds for supporting human bone stem cells.

    PubMed

    Petrochenko, Peter E; Torgersen, Jan; Gruber, Peter; Hicks, Lucas A; Zheng, Jiwen; Kumar, Girish; Narayan, Roger J; Goering, Peter L; Liska, Robert; Stampfl, Jürgen; Ovsianikov, Aleksandr

    2015-04-01

    A reproducible method is needed to fabricate 3D scaffold constructs that results in periodic and uniform structures with precise control at sub-micrometer and micrometer length scales. In this study, fabrication of scaffolds by two-photon polymerization (2PP) of a biodegradable urethane and acrylate-based photoelastomer is demonstrated. This material supports 2PP processing with sub-micrometer spatial resolution. The high photoreactivity of the biophotoelastomer permits 2PP processing at a scanning speed of 1000 mm s(-1), facilitating rapid fabrication of relatively large structures (>5 mm(3)). These structures are custom printed for in vitro assay screening in 96-well plates and are sufficiently flexible to enable facile handling and transplantation. These results indicate that stable scaffolds with porosities of greater than 60% can be produced using 2PP. Human bone marrow stromal cells grown on 3D scaffolds exhibit increased growth and proliferation compared to smooth 2D scaffold controls. 3D scaffolds adsorb larger amounts of protein than smooth 2D scaffolds due to their larger surface area; the scaffolds also allow cells to attach in multiple planes and to completely infiltrate the porous scaffolds. The flexible photoelastomer material is biocompatible in vitro and is associated with facile handling, making it a viable candidate for further study of complex 3D-printed scaffolds. PMID:25522214

  17. Living bacterial sacrificial porogens to engineer decellularized porous scaffolds.

    PubMed

    Xu, Feng; Sridharan, BanuPriya; Durmus, Naside Gozde; Wang, ShuQi; Yavuz, Ahmet Sinan; Gurkan, Umut Atakan; Demirci, Utkan

    2011-01-01

    Decellularization and cellularization of organs have emerged as disruptive methods in tissue engineering and regenerative medicine. Porous hydrogel scaffolds have widespread applications in tissue engineering, regenerative medicine and drug discovery as viable tissue mimics. However, the existing hydrogel fabrication techniques suffer from limited control over pore interconnectivity, density and size, which leads to inefficient nutrient and oxygen transport to cells embedded in the scaffolds. Here, we demonstrated an innovative approach to develop a new platform for tissue engineered constructs using live bacteria as sacrificial porogens. E.coli were patterned and cultured in an interconnected three-dimensional (3D) hydrogel network. The growing bacteria created interconnected micropores and microchannels. Then, the scafold was decellularized, and bacteria were eliminated from the scaffold through lysing and washing steps. This 3D porous network method combined with bioprinting has the potential to be broadly applicable and compatible with tissue specific applications allowing seeding of stem cells and other cell types. PMID:21552485

  18. Living Bacterial Sacrificial Porogens to Engineer Decellularized Porous Scaffolds

    PubMed Central

    Xu, Feng; Sridharan, BanuPriya; Durmus, Naside Gozde; Wang, ShuQi; Yavuz, Ahmet Sinan; Gurkan, Umut Atakan; Demirci, Utkan

    2011-01-01

    Decellularization and cellularization of organs have emerged as disruptive methods in tissue engineering and regenerative medicine. Porous hydrogel scaffolds have widespread applications in tissue engineering, regenerative medicine and drug discovery as viable tissue mimics. However, the existing hydrogel fabrication techniques suffer from limited control over pore interconnectivity, density and size, which leads to inefficient nutrient and oxygen transport to cells embedded in the scaffolds. Here, we demonstrated an innovative approach to develop a new platform for tissue engineered constructs using live bacteria as sacrificial porogens. E.coli were patterned and cultured in an interconnected three-dimensional (3D) hydrogel network. The growing bacteria created interconnected micropores and microchannels. Then, the scafold was decellularized, and bacteria were eliminated from the scaffold through lysing and washing steps. This 3D porous network method combined with bioprinting has the potential to be broadly applicable and compatible with tissue specific applications allowing seeding of stem cells and other cell types. PMID:21552485

  19. Tissue engineering scaffold material of porous nanohydroxyapatite/polyamide 66

    PubMed Central

    Xu, Qian; Lu, Hongyan; Zhang, Jingchao; Lu, Guoyu; Deng, Zhennan; Mo, Anchun

    2010-01-01

    The aim of the study was to investigate a porous nanohydroxyapatite/polyamide 66 (n-HA/PA66) scaffold material that was implanted into muscle and tibiae of 16 New Zealand white rabbits to evaluate the biocompatibility and osteogenesis and osteoinductivity of the materials in vivo. The samples were harvested at 2, 4, 12 and 26 weeks respectively, and subjected to histological analysis. At 2 weeks, the experiment showed that osteogenesis was detected in porous n-HA/PA66 composite and the density of new bone formation was similar to the surrounding host bone at 12 weeks. The study indicated that three-dimensional pore structures could facilitate cell adhesion, differentiation and proliferation, and help with fibrovascular and nerve colonization. In conclusion, porous n-HA/PA66 scaffold material could be a good candidate as a bone substitute material used in clinics due to its excellent histocompatibility, osteoconductivity and osteoinductivity. PMID:20517477

  20. Three-dimensional printing of porous ceramic scaffolds for bone tissue engineering.

    PubMed

    Seitz, Hermann; Rieder, Wolfgang; Irsen, Stephan; Leukers, Barbara; Tille, Carsten

    2005-08-01

    This article reports a new process chain for custom-made three-dimensional (3D) porous ceramic scaffolds for bone replacement with fully interconnected channel network for the repair of osseous defects from trauma or disease. Rapid prototyping and especially 3D printing is well suited to generate complex-shaped porous ceramic matrices directly from powder materials. Anatomical information obtained from a patient can be used to design the implant for a target defect. In the 3D printing technique, a box filled with ceramic powder is printed with a polymer-based binder solution layer by layer. Powder is bonded in wetted regions. Unglued powder can be removed and a ceramic green body remains. We use a modified hydroxyapatite (HA) powder for the fabrication of 3D printed scaffolds due to the safety of HA as biocompatible implantable material and efficacy for bone regeneration. The printed ceramic green bodies are consolidated at a temperature of 1250 degrees C in a high temperature furnace in ambient air. The polymeric binder is pyrolysed during sintering. The resulting scaffolds can be used in tissue engineering of bone implants using patient-derived cells that are seeded onto the scaffolds. This article describes the process chain, beginning from data preparation to 3D printing tests and finally sintering of the scaffold. Prototypes were successfully manufactured and characterized. It was demonstrated that it is possible to manufacture parts with inner channels with a dimension down to 450 microm and wall structures with a thickness down to 330 microm. The mechanical strength of dense test parts is up to 22 MPa. PMID:15981173

  1. Phenomenological study of Au and Pt nanowires grown in porous alumina scaffolds

    E-print Network

    Shin, Yong Cheol, Ph. D. Massachusetts Institute of Technology

    2011-01-01

    Porous anodic aluminum oxide, commonly known as AAO, has been widely used as a scaffold to synthesize nanowires and nanotubes. The porous alumina structure can be obtained from a simple electrochemical oxidation process, ...

  2. Effect of porous YSZ scaffold microstructure on the long-term performance of infiltrated Ni-YSZ anodes

    NASA Astrophysics Data System (ADS)

    Buyukaksoy, Aligul; Kammampata, Sanoop P.; Birss, Viola I.

    2015-08-01

    Ni infiltration into porous YSZ scaffolds is a promising route for the construction of high performing and redox-stable Ni-YSZ anodes for application in solid oxide fuel cells (SOFCs). However, the long-term instability of this type of anode is a critical problem. Here, it is shown that an interconnected Ni film, rather than discrete Ni particles, can be formed inside a porous, pre-sintered YSZ scaffold by using a polymeric Ni-based precursor as the infiltration medium. To understand the effect of the YSZ microstructure on the long-term stability and the electrochemical performance of the resulting composites, two types of Ni-YSZ anodes were investigated. Anodes prepared by polymeric Ni infiltration into a YSZ scaffold with large grains (0.5 ?m) and pores (0.5 ?m and 5 ?m) showed extensive agglomeration in the Ni phase, resulting in poor stability and poor activity. In contrast, Ni infiltration into YSZ scaffolds with finer particle and pore sizes (?200 nm each) produced anodes with a very small polarization resistance of ca. 0.1 ? cm2 per electrode at 800 °C. An increase of only ?5% was seen in the resistance after ca. 110 h at this temperature, achieved by preventing Ni agglomeration.

  3. Novel polymeric nanocomposites and porous materials prepared using organogels

    NASA Astrophysics Data System (ADS)

    Lai, Wei-Chi; Tseng, Shen-Chen

    2009-11-01

    We propose a new method for preparing polymeric nanocomposites and porous materials using self-assembled templates formed by 1,3:2,4-dibenzylidene sorbitol (DBS) organogels. DBS is capable of self-assembling into a 3D nanofibrillar network at relatively low concentrations in some organic solvents to produce organogels. In this study, we induced the formation of such physical cross-linked networks in styrene. Subsequently, we polymerized the styrene in the presence of chemical cross-linkers, divinyl benzene (DVB), with different amounts of DBS using thermal-initiated polymerization. The resulting materials were transparent, homogeneous polystyrene (PS) nanocomposites with both physical and chemical cross-links. The porous polymeric materials were obtained by solvent extraction of the DBS nanofibrils from the PS. Brunauer-Emmett-Teller (BET) measurements show that the amounts of DBS and DVB influenced the specific surface area after the removal of the DBS fibrils.

  4. Rapid prototyped porous nickel–titanium scaffolds as bone substitutes

    PubMed Central

    Hoffmann, Waldemar; Bormann, Therese; Rossi, Antonella; Müller, Bert; Schumacher, Ralf; Martin, Ivan; Wendt, David

    2014-01-01

    While calcium phosphate–based ceramics are currently the most widely used materials in bone repair, they generally lack tensile strength for initial load bearing. Bulk titanium is the gold standard of metallic implant materials, but does not match the mechanical properties of the surrounding bone, potentially leading to problems of fixation and bone resorption. As an alternative, nickel–titanium alloys possess a unique combination of mechanical properties including a relatively low elastic modulus, pseudoelasticity, and high damping capacity, matching the properties of bone better than any other metallic material. With the ultimate goal of fabricating porous implants for spinal, orthopedic and dental applications, nickel–titanium substrates were fabricated by means of selective laser melting. The response of human mesenchymal stromal cells to the nickel–titanium substrates was compared to mesenchymal stromal cells cultured on clinically used titanium. Selective laser melted titanium as well as surface-treated nickel–titanium and titanium served as controls. Mesenchymal stromal cells had similar proliferation rates when cultured on selective laser melted nickel–titanium, clinically used titanium, or controls. Osteogenic differentiation was similar for mesenchymal stromal cells cultured on the selected materials, as indicated by similar gene expression levels of bone sialoprotein and osteocalcin. Mesenchymal stromal cells seeded and cultured on porous three-dimensional selective laser melted nickel–titanium scaffolds homogeneously colonized the scaffold, and following osteogenic induction, filled the scaffold’s pore volume with extracellular matrix. The combination of bone-related mechanical properties of selective laser melted nickel–titanium with its cytocompatibility and support of osteogenic differentiation of mesenchymal stromal cells highlights its potential as a superior bone substitute as compared to clinically used titanium. PMID:25383165

  5. Diffusion model to describe osteogenesis within a porous titanium scaffold.

    PubMed

    Schmitt, M; Allena, R; Schouman, T; Frasca, S; Collombet, J M; Holy, X; Rouch, P

    2016-02-01

    In this study, we develop a two-dimensional finite element model, which is derived from an animal experiment and allows simulating osteogenesis within a porous titanium scaffold implanted in ewe's hemi-mandible during 12 weeks. The cell activity is described through diffusion equations and regulated by the stress state of the structure. We compare our model to (i) histological observations and (ii) experimental data obtained from a mechanical test done on sacrificed animal. We show that our mechano-biological approach provides consistent numerical results and constitutes a useful tool to predict osteogenesis pattern. PMID:25573031

  6. Porous polymeric materials for hydrogen storage

    DOEpatents

    Yu, Luping; Liu, Di-Jia; Yuan, Shengwen; Yang, Junbing

    2013-04-02

    A porous polymer, poly-9,9'-spirobifluorene and its derivatives for storage of H.sub.2 are prepared through a chemical synthesis method. The porous polymers have high specific surface area and narrow pore size distribution. Hydrogen uptake measurements conducted for these polymers determined a higher hydrogen storage capacity at the ambient temperature over that of the benchmark materials. The method of preparing such polymers, includes oxidatively activating solids by CO.sub.2/steam oxidation and supercritical water treatment.

  7. High porous titanium scaffolds showed higher compatibility than lower porous beta-tricalcium phosphate scaffolds for regulating human osteoblast and osteoclast differentiation.

    PubMed

    Hirota, Makoto; Hayakawa, Tohru; Shima, Takaki; Ametani, Akihiro; Tohnai, Iwai

    2015-04-01

    We compared osteoblast and osteoclast differentiation when using beta-tricalcium phosphate (?TCP) and titanium scaffolds by investigating human mesenchymal stem cells (hMSCs) and osteoclast progenitor cell activities. hMSCs were cultured for 7, 14, and 21days on titanium scaffolds with 60%, 73%, and 87% porosity and on ?TCP scaffolds with 60% and 75% porosity. Human osteoclast progenitor cells were cultured with osteoblast for 14 and 21days on 87% titanium and 75% ?TCP scaffolds. Viable cell numbers with 60% and 73% titanium were higher than with 87% titanium and ?TCP scaffolds (P<0.05). An 87% titanium scaffold resulted in the highest osteocalcin production with calcification on day 14 (P<0.01) in titanium scaffolds. All titanium scaffolds resulted in higher osteocalcin production on days 7 and 14 compared to ?TCP scaffolds (P<0.01). Osteoblasts cultured on 87% titanium scaffolds suppressed osteoclast differentiation on day 7 but enhanced osteoclast differentiation on day 14 compared to 75% ?TCP scaffolds (P<0.01). These findings concluded that high porosity titanium scaffolds could enhance progression of hMSC/osteoblast differentiation and regulated osteoclast differentiation cooperating with osteoblast differentiation for calcification as compared with lower porous ?TCP. PMID:25686991

  8. Porous polymeric materials for hydrogen storage

    DOEpatents

    Yu, Luping (Hoffman Estates, IL); Liu, Di-Jia (Naperville, IL); Yuan, Shengwen (Chicago, IL); Yang, Junbing (Westmont, IL)

    2011-12-13

    Porous polymers, tribenzohexazatriphenylene, poly-9,9'-spirobifluorene, poly-tetraphenyl methane and their derivatives for storage of H.sub.2 prepared through a chemical synthesis method. The porous polymers have high specific surface area and narrow pore size distribution. Hydrogen uptake measurements conducted for these polymers determined a higher hydrogen storage capacity at the ambient temperature over that of the benchmark materials. The method of preparing such polymers, includes oxidatively activating solids by CO.sub.2/steam oxidation and supercritical water treatment.

  9. Delivery of growth factors using a smart porous nanocomposite scaffold to repair a mandibular bone defect.

    PubMed

    Liu, Xian; Zhao, Kun; Gong, Tao; Song, Jian; Bao, Chongyun; Luo, En; Weng, Jie; Zhou, Shaobing

    2014-03-10

    Implantation of a porous scaffold with a large volume into the body in a convenient and safe manner is still a challenging task in the repair of bone defects. In this study, we present a porous smart nanocomposite scaffold with a combination of shape memory function and controlled delivery of growth factors. The shape memory function enables the scaffold with a large volume to be deformed into its temporal architecture with a small volume using hot-compression and can subsequently recover its original shape upon exposure to body temperature after it is implanted in the body. The scaffold consists of chemically cross-linked poly(?-caprolactone) (c-PCL) and hydroxyapatite nanoparticles. The highly interconnected pores of the scaffold were obtained using the sugar leaching method. The shape memory porous scaffold loaded with bone morphogenetic protein-2 (BMP-2) was also fabricated by coating the calcium alginate layer and BMP-2 on the surface of the pore wall. Under both in vitro and in vivo environmental conditions, the porous scaffold displays good shape memory recovery from the compressed shape with deformed pores of 33 ?m in diameter to recover its porous shape with original pores of 160 ?m in diameter. In vitro cytotoxicity based on the MTT test revealed that the scaffold exhibited good cytocompatibility. The in vivo micro-CT and histomorphometry results demonstrated that the porous scaffold could promote new bone generation in the rabbit mandibular bone defect. Thus, our results indicated that this shape memory porous scaffold demonstrated great potential for application in bone regenerative medicine. PMID:24467335

  10. Designing and modeling doubly porous polymeric materials

    NASA Astrophysics Data System (ADS)

    Ly, H.-B.; Le Droumaguet, B.; Monchiet, V.; Grande, D.

    2015-07-01

    Doubly porous organic materials based on poly(2-hydroxyethyl methacrylate) are synthetized through the use of two distinct types of porogen templates, namely a macroporogen and a nanoporogen. Two complementary strategies are implemented by using either sodium chloride particles or fused poly(methyl methacrylate) beads as macroporogens, in conjunction with ethanol as a porogenic solvent. The porogen removal respectively allows for the generation of either non-interconnected or interconnected macropores with an average diameter of about 100-200 ?m and nanopores with sizes lying within the 100 nm order of magnitude, as evidenced by mercury intrusion porosimetry and scanning electron microscopy. Nitrogen sorption measurements evidence the formation of materials with rather high specific surface areas, i.e. higher than 140 m2.g-1. This paper also addresses the development of numerical tools for computing the permeability of such doubly porous materials. Due to the coexistence of well separated scales between nanopores and macropores, a consecutive double homogenization approach is proposed. A nanoscopic scale and a mesoscopic scale are introduced, and the flow is evaluated by means of the Finite Element Method to determine the macroscopic permeability. At the nanoscopic scale, the flow is described by the Stokes equations with an adherence condition at the solid surface. At the mesoscopic scale, the flow obeys the Stokes equations in the macropores and the Darcy equation in the permeable polymer in order to account for the presence of the nanopores.

  11. Kinetics and isotherm of fibronectin adsorption to three-dimensional porous chitosan scaffolds explored by 125I-radiolabelling

    PubMed Central

    Amaral, Isabel F.; Sousa, Susana R.; Neiva, Ismael; Marcos-Silva, Lara; Kirkpatrick, Charles J.; Barbosa, Mário A.; Pêgo, Ana P.

    2013-01-01

    In this study, 125I-radiolabelling was explored to follow the kinetics and isotherm of fibronectin (FN) adsorption to porous polymeric scaffolds, as well as to assess the elution and exchangeability of pre-adsorbed FN following incubation in serum-containing culture medium. Chitosan (CH) porous scaffolds with two different degrees of acetylation (DA 4% and 15%) were incubated in FN solutions with concentrations ranging from 5 to 50 µg/mL. The kinetic and isotherm of FN adsorption to CH were successfully followed using 125I-FN as a tracer molecule. While on DA 4% the levels of adsorbed FN increased linearly with FN solution concentration, on DA 15% a saturation plateau was attained, and FN adsorbed amounts were significantly lower. These findings were supported by immunofluorescent studies that revealed, for the same FN solution concentration, higher levels of exposed cell-binding domains on DA 4% as compared with DA 15%. Following incubation in serum containing medium, DA 4% also revealed higher ability to exchange pre-adsorbed FN by new FN molecules from serum than DA 15%. In accordance, when assessing the efficacy of passively adsorbed FN to promote endothelial cell (EC) adhesion to CH, ECs were found to adhere at higher levels to DA 4% as compared with DA 15%, 5 µg/mL of FN being already efficient in promoting cell adhesion and cytoskeletal organization on CH with DA 4%. Taken together the results show that protein radiolabelling can be used as an effective tool to study protein adsorption to porous polymeric scaffolds, both from single and complex protein solutions. PMID:23635535

  12. Nanoscale Control of Silks for Nanofibrous Scaffold Formation with Improved Porous Structure

    PubMed Central

    Lin, Shasha; Lu, Guozhong; Liu, Shanshan; Bai, Shumeng; Liu, Xi; Lu, Qiang; Zuo, Baoqi; Kaplan, David L.; Zhu, Hesun

    2014-01-01

    Silk-based porous scaffolds have been used extensively in tissue engineering because of their excellent biocompatibility, tunable biodegradability and robust mechanical properties. Although many silk-based scaffolds have been prepared through freeze-drying, a challenge remains to effectively control porous structures during this process. In the present study silk fibroin with different nanostructures were self-assembled in aqueous solution by repeated drying-dissolving process and then used to improve porous structure formation in lyophilization process. Viscosity, secondary structures and water interactions were also studied to exclude their influence on the formation and control of porous structures. Following nanofiber formation in aqueous solution, silk scaffolds with improved porous structure were directly formed after lyophilization and then stabilized with water or methanol annealing treatments. Compared to silk scaffolds derived from fresh solution, the nanofibrous scaffolds showed significantly better cell compatibility in vitro. Therefore, this nanoscale control of silk offers feasible way to regulate the matrix features including porous structure and nanostructure, which are important in regulating cell and tissue outcomes in tissue engineering and regeneration, and then achieve silk-based scaffolds with improved properties. PMID:24949200

  13. Peracetic Acid: A Practical Agent for Sterilizing Heat-Labile Polymeric Tissue-Engineering Scaffolds

    PubMed Central

    Yoganarasimha, Suyog; Trahan, William R.; Best, Al M.; Bowlin, Gary L.; Kitten, Todd O.; Moon, Peter C.

    2014-01-01

    Advanced biomaterials and sophisticated processing technologies aim at fabricating tissue-engineering scaffolds that can predictably interact within a biological environment at the cellular level. Sterilization of such scaffolds is at the core of patient safety and is an important regulatory issue that needs to be addressed before clinical translation. In addition, it is crucial that meticulously engineered micro- and nano- structures are preserved after sterilization. Conventional sterilization methods involving heat, steam, and radiation are not compatible with engineered polymeric systems because of scaffold degradation and loss of architecture. Using electrospun scaffolds made from polycaprolactone, a low melting polymer, and employing spores of Bacillus atrophaeus as biological indicators, we compared ethylene oxide, autoclaving and 80% ethanol to a known chemical sterilant, peracetic acid (PAA), for their ability to sterilize as well as their effects on scaffold properties. PAA diluted in 20% ethanol to 1000?ppm or above sterilized electrospun scaffolds in 15?min at room temperature while maintaining nano-architecture and mechanical properties. Scaffolds treated with PAA at 5000?ppm were rendered hydrophilic, with contact angles reduced to 0°. Therefore, PAA can provide economical, rapid, and effective sterilization of heat-sensitive polymeric electrospun scaffolds that are used in tissue engineering. PMID:24341350

  14. Peracetic acid: a practical agent for sterilizing heat-labile polymeric tissue-engineering scaffolds.

    PubMed

    Yoganarasimha, Suyog; Trahan, William R; Best, Al M; Bowlin, Gary L; Kitten, Todd O; Moon, Peter C; Madurantakam, Parthasarathy A

    2014-09-01

    Advanced biomaterials and sophisticated processing technologies aim at fabricating tissue-engineering scaffolds that can predictably interact within a biological environment at the cellular level. Sterilization of such scaffolds is at the core of patient safety and is an important regulatory issue that needs to be addressed before clinical translation. In addition, it is crucial that meticulously engineered micro- and nano- structures are preserved after sterilization. Conventional sterilization methods involving heat, steam, and radiation are not compatible with engineered polymeric systems because of scaffold degradation and loss of architecture. Using electrospun scaffolds made from polycaprolactone, a low melting polymer, and employing spores of Bacillus atrophaeus as biological indicators, we compared ethylene oxide, autoclaving and 80% ethanol to a known chemical sterilant, peracetic acid (PAA), for their ability to sterilize as well as their effects on scaffold properties. PAA diluted in 20% ethanol to 1000 ppm or above sterilized electrospun scaffolds in 15 min at room temperature while maintaining nano-architecture and mechanical properties. Scaffolds treated with PAA at 5000 ppm were rendered hydrophilic, with contact angles reduced to 0°. Therefore, PAA can provide economical, rapid, and effective sterilization of heat-sensitive polymeric electrospun scaffolds that are used in tissue engineering. PMID:24341350

  15. Fabrication of uniformly cell-laden porous scaffolds using a gas-in-liquid templating technique.

    PubMed

    Takei, Takayuki; Aokawa, Ryuta; Shigemitsu, Takamasa; Kawakami, Koei; Yoshida, Masahiro

    2015-11-01

    Design of porous scaffolds in tissue engineering field was challenging. Uniform immobilization of cells in the scaffolds with high porosity was essential for homogeneous tissue formation. The present study was aimed at fabricating uniformly cell-laden porous scaffolds with porosity >74% using the gas-in-liquid foam templating technique. To this end, we used gelatin, microbial transglutaminase and argon gas as a scaffold material, cross-linker of the protein and porogen of scaffold, respectively. We confirmed that a porosity of >74% could be achieved by increasing the gas volume delivered to a gelatin solution. Pore size in the scaffold could be controlled by stirring speed, stirring time and the pore size of the filter through which the gas passed. The foaming technique enabled us to uniformly immobilize a human hepatoblastoma cell line in scaffold. Engraftment efficiency of the cell line entrapped within the scaffold in nude mice was higher than that of cells in free-form. These results showed that the uniformly cell-laden porous scaffolds were promising for tissue engineering. PMID:25912452

  16. Development of porous Ti6Al4V/chitosan sponge composite scaffold for orthopedic applications.

    PubMed

    Guo, Miao; Li, Xiang

    2016-01-01

    A novel composite scaffold consisting of porous Ti6Al4V part filled with chitosan sponge was fabricated using a combination of electron beam melting and freeze-drying. The mechanical properties of porous Ti6Al4V part were examined via compressive test. The ultimate compressive strength was 85.35±8.68MPa and the compressive modulus was 2.26±0.42GPa. The microstructure of composite scaffold was characterized using scanning electron microscopy. The chitosan sponge filled in Ti6Al4V part exhibited highly porous and well-interconnected micro-pore architecture. The osteoblastic cells were seeded on scaffolds to test their seeding efficiency and biocompatibility. Significantly higher cell seeding efficiency was found on composite scaffold. The biological response of osteoblasts on composite scaffolds was superior in terms of improved cell attachment, higher proliferation, and well-spread morphology in relation to porous Ti6Al4V part. These results suggest that the Ti6Al4V/chitosan composite scaffold is potentially useful as a biomedical scaffold for orthopedic applications. PMID:26478418

  17. Construction of biocompatible porous tissue scaffold from the decellularized umbilical artery.

    PubMed

    Xin, Yi; Wu, Guanghui; Wu, Man; Zhang, Xiaoxia; Velot, Emilie; Decot, Véronique; Cui, Wei; Huang, Yimin; Stoltz, Jean-Francois; Du, Jie; Li, Na

    2015-01-01

    The scaffolds prepared from the tissue decellularization conserve the porous 3-D structure and provide an optimal matrix for the tissue regeneration. Since decade, the enzymatic digestion, chemical reagent treatment and mechanical actions such as eversion and abrasion have been used to remove the cells from the intact matrix. In this study, we optimized an enzymatic method to decellularize the umbilical artery to construct a 3-D porous scaffold which is suitable for the culture of mesenchymal stem cells (MSCs). The scaffold maintained the interconnected porous structure. It remained the similar high water content 95.3 ± 1% compared to 94.9 ± 0.6% in the intact umbilical artery (p>0.05). The decellularization process decreased the stress from 0.24 ± 0.05 mPa to 0.15 ± 0.06 mPa (p<0.05). However the decellularization did not change the strain of the artery (45 ± 15% vs. 53 ± 10%, p>0.05). When the scaffold was transplanted to the subcutaneous tissue in the wild type mice, there were less T cells appeared in the surrounding tissue which meant the decreased the immunogenicity by decellularization. This scaffold also supported the adhesion and proliferation of the MSCs. In this study, we constructed a biological compatible porous scaffold from the decellularized umbilical artery which may provide a suitable scaffold for cell-matrix interaction studies and for tissue engineering. PMID:25538057

  18. Biomedical Applications of Emulsion Templated Scaffolds 

    E-print Network

    Moglia, Robert Scott

    2014-03-28

    . To this end, we have utilized emulsion templating to create injectable polyHIPE scaffolds that are biodegradable, highly porous, polymerize at body temperature, and possess appropriate and tunable mechanical properties for tissue regeneration. Poly...

  19. Porous chitosan-hyaluronic acid scaffolds as a mimic of glioblastoma microenvironment ECM

    PubMed Central

    Jana, Soumen; Wood, David L.; Sytsma, Samara K.; Sham, Jonathan; Kievit, Forrest M.; Zhang, Miqin

    2013-01-01

    Cancer therapeutics are developed through extensive screening; however, many therapeutics evaluated with 2D in vitro cultures during pre-clinical trials suffer from lower efficacy in patients. Replicating the in vivo tumor microenvironment in vitro with three-dimensional (3D) porous scaffolds offers the possibility of generating more predictive pre-clinical models to enhance cancer treatment efficacy. We developed a chitosan and hyaluronic acid (HA) polyelectrolyte complex 3D porous scaffold and evaluated its physical properties. Chitosan-HA (C-HA) scaffolds had a highly porous network. C-HA scaffolds were compared to 2D surfaces for in vitro culture of U-118 MG human glioblastoma (GBM) cells. C-HA scaffold cultures promoted tumor spheroid formation and increased stem-like properties of GBM cells as evidenced by the upregulation of CD44, Nestin, Musashi-1, GFAP, and HIF-1? as compared with 2D cultures. Additionally, the invasiveness of GBM cells cultured in C-HA scaffolds was significantly enhanced compared to those grown in 2D cultures. C-HA scaffold cultures were also more resistant to chemotherapy drugs, which corresponded to the increased expression of ABCG2 drug efflux transporter. These findings suggest that C-HA scaffolds offer promise as an in vitro GBM platform for study and screening of novel cancer therapeutics. PMID:24075410

  20. Biomechanical and biocompatibility characteristics of electrospun polymeric tracheal scaffolds.

    PubMed

    Ajalloueian, Fatemeh; Lim, Mei Ling; Lemon, Greg; Haag, Johannes C; Gustafsson, Ylva; Sjöqvist, Sebastian; Beltrán-Rodríguez, Antonio; Del Gaudio, Costantino; Baiguera, Silvia; Bianco, Alessandra; Jungebluth, Philipp; Macchiarini, Paolo

    2014-07-01

    The development of tracheal scaffolds fabricated based on electrospinning technique by applying different ratios of polyethylene terephthalate (PET) and polyurethane (PU) is introduced here. Prior to clinical implantation, evaluations of biomechanical and morphological properties, as well as biocompatibility and cell adhesion verifications are required and extensively performed on each scaffold type. However, the need for bioreactors and large cell numbers may delay the verification process during the early assessment phase. Hence, we investigated the feasibility of performing biocompatibility verification using static instead of dynamic culture. We performed bioreactor seeding on 3-dimensional (3-D) tracheal scaffolds (PET/PU and PET) and correlated the quantitative and qualitative results with 2-dimensional (2-D) sheets seeded under static conditions. We found that an 8-fold reduction for 2-D static seeding density can essentially provide validation on the qualitative and quantitative evaluations for 3-D scaffolds. In vitro studies revealed that there was notably better cell attachment on PET sheets/scaffolds than with the polyblend. However, the in vivo outcomes of cell seeded PET/PU and PET scaffolds in an orthotopic transplantation model in rodents were similar. They showed that both the scaffold types satisfied biocompatibility requirements and integrated well with the adjacent tissue without any observation of necrosis within 30 days of implantation. PMID:24703872

  1. Fabrication and characterization of interconnected porous biodegradable poly(?-caprolactone) load bearing scaffolds.

    PubMed

    Allaf, Rula M; Rivero, Iris V

    2011-08-01

    In this study, poly(?-caprolactone) (PCL)/poly(ethylene oxide) (PEO) (50:50 wt%) immiscible blend was used as a model system to investigate the feasibility of a novel solventless fabrication approach that combines cryomilling, compression molding and porogen leaching techniques to prepare interconnected porous scaffolds for tissue engineering. PCL was cryomilled with PEO to form blend powders. Compression molding was used to consolidate and anneal the cryomilled powders. Selective dissolution of the PEO with water resulted in interconnected porous scaffolds. Sodium chloride salt (NaCl) was subsequently added to cryomilled powder to increase the porosity of scaffolds. The prepared scaffolds had homogeneous pore structures, a porosity of ~50% which was increased by mixing salt with the blend (~70% for 60% wt% NaCl), and a compressive modulus and strength (? = 10%) of 60 and 2.8 MPa, respectively. The results of the study confirm that this novel approach offers a viable alternative to fabricate scaffolds. PMID:21670998

  2. Ultrafast Spreading Effect Induced Rapid Cell Trapping into Porous Scaffold with Superhydrophilic Surface.

    PubMed

    Wang, Chenmiao; Qiao, Chunyan; Song, Wenlong; Sun, Hongchen

    2015-08-19

    In this contribution, superhydrophilic chitosan-based scaffolds with ultrafast spreading property were fabricated and used to improve the trapped efficiency of cells. The ultrafast spreading property allowed cells to be trapped into the internal 3D porous structures of the prepared scaffolds more quickly and effectively. Cell adhesion, growth, and proliferation were also improved, which could be attributed to the combination of UV irradiation and ultrafast spreading property. The construction of ultrafast spreading property on the scaffold surface will offer a novel way to design more effective scaffold in tissue engineering that could largely shorten the therapeutic time for patients. PMID:26234569

  3. Large Scale Laser Two-Photon Polymerization Structuring for Fabrication of Artificial Polymeric Scaffolds for Regenerative Medicine

    SciTech Connect

    Malinauskas, M.; Purlys, V.; Zukauskas, A.; Rutkauskas, M.; Danilevicius, P.; Paipulas, D.; Bickauskaite, G.; Gadonas, R.; Piskarskas, A.; Bukelskis, L.; Baltriukiene, D.; Bukelskiene, V.; Sirmenis, R.; Gaidukeviciute, A.; Sirvydis, V.

    2010-11-10

    We present a femtosecond Laser Two-Photon Polymerization (LTPP) system of large scale three-dimensional structuring for applications in tissue engineering. The direct laser writing system enables fabrication of artificial polymeric scaffolds over a large area (up to cm in lateral size) with sub-micrometer resolution which could find practical applications in biomedicine and surgery. Yb:KGW femtosecond laser oscillator (Pharos, Light Conversion. Co. Ltd.) is used as an irradiation source (75 fs, 515 nm (frequency doubled), 80 MHz). The sample is mounted on wide range linear motor driven stages having 10 nm sample positioning resolution (XY--ALS130-100, Z--ALS130-50, Aerotech, Inc.). These stages guarantee an overall travelling range of 100 mm into X and Y directions and 50 mm in Z direction and support the linear scanning speed up to 300 mm/s. By moving the sample three-dimensionally the position of laser focus in the photopolymer is changed and one is able to write complex 3D (three-dimensional) structures. An illumination system and CMOS camera enables online process monitoring. Control of all equipment is automated via custom made computer software ''3D-Poli'' specially designed for LTPP applications. Structures can be imported from computer aided design STereoLihography (stl) files or programmed directly. It can be used for rapid LTPP structuring in various photopolymers (SZ2080, AKRE19, PEG-DA-258) which are known to be suitable for bio-applications. Microstructured scaffolds can be produced on different substrates like glass, plastic and metal. In this paper, we present microfabricated polymeric scaffolds over a large area and growing of adult rabbit myogenic stem cells on them. Obtained results show the polymeric scaffolds to be applicable for cell growth practice. It exhibit potential to use it for artificial pericardium in the experimental model in the future.

  4. Large Scale Laser Two-Photon Polymerization Structuring for Fabrication of Artificial Polymeric Scaffolds for Regenerative Medicine

    NASA Astrophysics Data System (ADS)

    Malinauskas, M.; Purlys, V.; Žukauskas, A.; Rutkauskas, M.; Danilevi?ius, P.; Paipulas, D.; Bi?kauskait?, G.; Bukelskis, L.; Baltriukien?, D.; Širmenis, R.; Gaidukevi?iut?, A.; Bukelskien?, V.; Gadonas, R.; Sirvydis, V.; Piskarskas, A.

    2010-11-01

    We present a femtosecond Laser Two-Photon Polymerization (LTPP) system of large scale three-dimensional structuring for applications in tissue engineering. The direct laser writing system enables fabrication of artificial polymeric scaffolds over a large area (up to cm in lateral size) with sub-micrometer resolution which could find practical applications in biomedicine and surgery. Yb:KGW femtosecond laser oscillator (Pharos, Light Conversion. Co. Ltd.) is used as an irradiation source (75 fs, 515 nm (frequency doubled), 80 MHz). The sample is mounted on wide range linear motor driven stages having 10 nm sample positioning resolution (XY—ALS130-100, Z—ALS130-50, Aerotech, Inc.). These stages guarantee an overall travelling range of 100 mm into X and Y directions and 50 mm in Z direction and support the linear scanning speed up to 300 mm/s. By moving the sample three-dimensionally the position of laser focus in the photopolymer is changed and one is able to write complex 3D (three-dimensional) structures. An illumination system and CMOS camera enables online process monitoring. Control of all equipment is automated via custom made computer software "3D-Poli" specially designed for LTPP applications. Structures can be imported from computer aided design STereoLihography (stl) files or programmed directly. It can be used for rapid LTPP structuring in various photopolymers (SZ2080, AKRE19, PEG-DA-258) which are known to be suitable for bio-applications. Microstructured scaffolds can be produced on different substrates like glass, plastic and metal. In this paper, we present microfabricated polymeric scaffolds over a large area and growing of adult rabbit myogenic stem cells on them. Obtained results show the polymeric scaffolds to be applicable for cell growth practice. It exhibit potential to use it for artificial pericardium in the experimental model in the future.

  5. Poly(lactide-co-glycolide) porous scaffolds for tissue engineering and regenerative medicine

    PubMed Central

    Pan, Zhen; Ding, Jiandong

    2012-01-01

    Porous scaffolds fabricated from biocompatible and biodegradable polymers play vital roles in tissue engineering and regenerative medicine. Among various scaffold matrix materials, poly(lactide-co-glycolide) (PLGA) is a very popular and an important biodegradable polyester owing to its tunable degradation rates, good mechanical properties and processibility, etc. This review highlights the progress on PLGA scaffolds. In the latest decade, some facile fabrication approaches at room temperature were put forward; more appropriate pore structures were designed and achieved; the mechanical properties were investigated both for dry and wet scaffolds; a long time biodegradation of the PLGA scaffold was observed and a three-stage model was established; even the effects of pore size and porosity on in vitro biodegradation were revealed; the PLGA scaffolds have also been implanted into animals, and some tissues have been regenerated in vivo after loading cells including stem cells. PMID:23741612

  6. Incorporation of polymeric microparticles into collagen-hydroxyapatite scaffolds for the delivery of a pro-osteogenic peptide for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    López-Noriega, Adolfo; Quinlan, Elaine; Celikkin, Nehar; O'Brien, Fergal J.

    2015-01-01

    Collagen-hydroxyapatite scaffolds are outstanding materials for bone tissue engineering as they are biocompatible, bioresorbable, osteoconductive, and osteoinductive. The objective of the present work was to assess the potential of increasing their regenerative capacity by functionalising the scaffolds for therapeutic delivery. This was achieved by the utilization of polymeric drug carriers. With this purpose, alginate, chitosan, gelatine, and poly(lactic-co-glycolic acid) (PLGA) microparticles eluting PTHrP 107-111, an osteogenic pentapeptide, were fabricated and tested by incorporating them into the scaffolds. Among them, PLGA microparticles show the most promising characteristics for use as drug delivery devices. Following the incorporation of the microparticles, the scaffolds maintained their interconnected porous structure and the mechanical properties of the materials were not adversely affected. In addition, the microparticles released all their PTHrP 107-111 cargo. Most importantly, the delivered peptide proved to be bioactive and promoted enhanced osteogenesis as assessed by alkaline phosphatase production and osteocalcin and osteopontin gene expression when pre-osteoblastic cells were seeded on the scaffolds. While the focus was on bone repair, the release system described in this study can be used for the delivery of therapeutics for healing and regeneration of a variety of tissue types depending on the type of collagen scaffold chosen.

  7. In vitro bioactivity and degradability of ?-tricalcium phosphate porous scaffold fabricated via selective laser sintering.

    PubMed

    Shuai, Cijun; Zhuang, Jingyu; Hu, Huanlong; Peng, Shuping; Liu, Defu; Liu, Jinglin

    2013-01-01

    Porous scaffolds consisting of ?-tricalcium phosphate (?-TCP) were successfully fabricated via selective laser sintering. The scaffolds had a controlled microstructure and totally interconnected porous structure. The microstructure and mechanical properties were studied. The bioactivity and degradability of scaffolds were evaluated through the simulated body fluid (SBF) cultivation experiment. The formation of a biologically active carbonate apatite layer on the surface after immersion in SBF was demonstrated using scanning electron microscope, energy dispersive X-ray, and Fourier transform infrared spectroscopy. Fast nucleation and growth of the carbonate apatite crystals were observed to occur all through the specimen surfaces. The phenomenon was explained in terms of the distribution and dispersion of inorganic phases in the scaffolds and the ionic activity products of the apatite in the SBF. The calculation results of weight loss and Ca/P molar ratio also suggest the good bioactivity and degradability of the scaffolds. These indicate that the ?-TCP porous ceramic scaffold is a potential candidate scaffold for bone tissue engineering. PMID:23600577

  8. Biological advantages of porous hydroxyapatite scaffold made by solid freeform fabrication for bone tissue regeneration.

    PubMed

    Kwon, Byeong-Ju; Kim, Jungsung; Kim, Yong Hwa; Lee, Mi Hee; Baek, Hyun Sook; Lee, Dae Hyung; Kim, Hye-Lee; Seo, Hyok Jin; Lee, Min Hyeon; Kwon, Soon-Young; Koo, Min-Ah; Park, Jong-Chul

    2013-07-01

    Presently, commercially available porous bone substitutes are manufactured by the sacrificial template method, direct foaming method, and polymer replication method (PRM). However, current manufacturing methods provide only the simplest form of the bone scaffold and cannot easily control pore size. Recent developments in medical imaging technology, computer-aided design, and solid freeform fabrication (SFF), have made it possible to accurately produce porous synthetic bone scaffolds to fit the defected bone shape. Porous scaffolds were fabricated by SFF and PRM for a comparison of physical and mechanical properties of scaffold. The suggested three-dimensional model has interconnected cubic pores of 500??m and its calculated porosity is 25%. Whereas hydroxyapatite scaffolds fabricated by SFF had connective macropores, those by PRM formed a closed pore external surface with internally interconnected pores. SFF was supposed to be a proper method for fabricating an interconnected macroporous network. Biocompatibility was confirmed by testing the cytotoxicity, hemolysis, irritation, sensitization, and implantation. In summary, the aim was to verify the safety and efficacy of the scaffolds by biomechanical and biological tests with the hope that this research could promote the feasibility of using the scaffolds as a bone substitute. PMID:23419084

  9. A Novel Porous Scaffold Fabrication Technique for Epithelial and Endothelial Tissue Engineering

    PubMed Central

    McHugh, Kevin J.; Tao, Sarah L.; Saint-Geniez, Magali

    2014-01-01

    Porous scaffolds have the ability to minimize transport barriers for both two- (2D) and three-dimensional tissue engineering. However, current porous scaffolds may be non-ideal for 2D tissues such as epithelium due to inherent fabrication-based characteristics. While 2D tissues require porosity to support molecular transport, pores must be small enough to prevent cell migration into the scaffold in order to avoid non-epithelial tissue architecture and compromised function. Though electrospun meshes are the most popular porous scaffolds used today, their heterogeneous pore size and intense topography may be poorly-suited for epithelium. Porous scaffolds produced using other methods have similar unavoidable limitations, frequently involving insufficient pore resolution and control, which make them incompatible with 2D tissues. In addition, many of these techniques require an entirely new round of process development in order to change material or pore size. Herein we describe “pore casting,” a fabrication method that produces flat scaffolds with deterministic pore shape, size, and location that can be easily altered to accommodate new materials or pore dimensions. As proof-of-concept, pore-cast poly(?-caprolactone) (PCL) scaffolds were fabricated and compared to electrospun PCL in vitro using canine kidney epithelium, human colon epithelium, and human umbilical vein endothelium. All cell types demonstrated improved morphology and function on pore-cast scaffolds, likely due to reduced topography and universally small pore size. These results suggest that pore casting is an attractive option for creating 2D tissue engineering scaffolds, especially when the application may benefit from well-controlled pore size or architecture. PMID:23625319

  10. Development of Composite Porous Scaffolds Based on Collagen and Biodegradable Poly(ester urethane)urea

    PubMed Central

    Guan, Jianjun; Stankus, John J.; Wagner, William R.

    2010-01-01

    Our objective in this work was to develop a flexible, biodegradable scaffold for cell transplantation that would incorporate a synthetic component for strength and flexibility and type I collagen for enzymatic lability and cytocompatibility. A biodegradable poly(ester urethane)urea was synthesized from poly(caprolactone), 1,4-diisocyanatobutane, and putrescine. Using a thermally induced phase separation process, porous scaffolds were created from a mixture containing this polyurethane and 0%, 10%, 20%, or 30% type I collagen. The resulting scaffolds were found to have open, interconnected pores (from 7 to >100 um) and porosities from 58% to 86% depending on the polyurethane/collagen ratio. The scaffolds were also flexible with breaking strains of 82–443% and tensile strengths of 0.97–4.11 MPa depending on preparation conditions. Scaffold degradation was significantly increased when collagenase was introduced into an incubating buffer in a manner that was dependent on the mass fraction of collagen present in the scaffold. Mass losses could be varied from 15% to 59% over 8 weeks. When culturing umbilical artery smooth muscle cells on these scaffolds higher cell numbers were observed over a 4-week culture period in scaffolds containing collagen. In summary, a strong and flexible scaffold system has been developed that can degrade by both hydrolysis and collagenase degradation pathways, as well as support cell growth. This scaffold possesses properties that would make it attractive for future use in soft tissue applications where such mechanical and biological features would be advantageous. PMID:16826792

  11. Porous polymer scaffold for on-site delivery of stem cells - Protects from oxidative stress and potentiates wound tissue repair.

    PubMed

    Geesala, Ramasatyaveni; Bar, Nimai; Dhoke, Neha R; Basak, Pratyay; Das, Amitava

    2016-01-01

    Wound healing by cell transplantation techniques often suffer setbacks due to oxidative stress encountered at injury sites. A porous polyethyleneglycol-polyurethane (PEG-PU) scaffold that facilitates cell delivery and boosts tissue repair was developed through semi-interpenetrating polymer network approach. The key physico-chemical properties assessed confirms these polymeric matrices are highly thermostable, barostable, degrade at an acidic pH (5.8), biodegradable, cytocompatible and possess excellent porosity. Mechanism of cellular penetration into porous polymer networks was evident by a ?6 - fold increase in gene expression of MMP-13 and MMP-2 via activation of Akt and Erk. H2O2-induced apoptosis of mouse bone marrow stem cells (BMSCs) was abrogated in presence of polymer networks indicating a protective effect from oxidative stress. Transplantation of BMSC + PEG-PU at murine excisional splint wound site depicted significant increase in fibroblast proliferation, collagen deposition, anti-oxidant enzyme activities of catalase, SOD and GPx. Furthermore it significantly decreased expression of pro-inflammatory cytokines (IL-1?, TNF-?, IL-8, etc) with a concomitant increase in anti-inflammatory cytokines (IL-10, IL-13) at an early healing period of day 7. Finally, immunostaining revealed an enhanced engraftment and vascularity indicating an accelerated wound tissue closure. This pre-clinical study demonstrates the proof-of-concept and further necessitates their clinical evaluation as potential cell delivery vehicle scaffolds. PMID:26576045

  12. Label-free magnetic resonance imaging to locate live cells in three-dimensional porous scaffolds

    PubMed Central

    Abarrategi, A.; Fernandez-Valle, M. E.; Desmet, T.; Castejón, D.; Civantos, A.; Moreno-Vicente, C.; Ramos, V.; Sanz-Casado, J. V.; Martínez-Vázquez, F. J.; Dubruel, P.; Miranda, P.; López-Lacomba, J. L.

    2012-01-01

    Porous scaffolds are widely tested materials used for various purposes in tissue engineering. A critical feature of a porous scaffold is its ability to allow cell migration and growth on its inner surface. Up to now, there has not been a method to locate live cells deep inside a material, or in an entire structure, using real-time imaging and a non-destructive technique. Herein, we seek to demonstrate the feasibility of the magnetic resonance imaging (MRI) technique as a method to detect and locate in vitro non-labelled live cells in an entire porous material. Our results show that the use of optimized MRI parameters (4.7 T; repetition time = 3000 ms; echo time = 20 ms; resolution 39 × 39 µm) makes it possible to obtain images of the scaffold structure and to locate live non-labelled cells in the entire material, with a signal intensity higher than that obtained in the culture medium. In the current study, cells are visualized and located in different kinds of porous scaffolds. Moreover, further development of this MRI method might be useful in several three-dimensional biomaterial tests such as cell distribution studies, routine qualitative testing methods and in situ monitoring of cells inside scaffolds. PMID:22442095

  13. Tailoring properties of porous Poly (vinylidene fluoride) scaffold through nano-sized 58s bioactive glass.

    PubMed

    Shuai, Cijun; Huang, Wei; Feng, Pei; Gao, Chengde; Shuai, Xiong; Xiao, Tao; Deng, Youwen; Peng, Shuping; Wu, Ping

    2016-01-01

    The biological properties of porous poly (vinylidene fluoride) (PVDF) scaffolds fabricated by selective laser sintering were tailored through nano-sized 58s bioactive glass. The results showed that 58s bioactive glass distributed evenly in the PVDF matrix. There were some exposed particles on the surface which provided attachment sites for biological response. It was confirmed that the scaffolds had highly bioactivity by the formation of bone-like apatite in simulated body fluid. And the bone-like apatite became dense with the increase in 58s bioactive glass and culture time. Moreover, the scaffolds were suitable for cell adhesion and proliferation compared with the PVDF scaffolds without 58s bioactive glass. The research showed that the PVDF/58s bioactive glass scaffolds had latent application in bone tissue engineering. PMID:26592544

  14. Interfacing polymeric scaffolds with primary pancreatic ductal adenocarcinoma cells to develop 3D cancer models

    PubMed Central

    Ricci, Claudio; Mota, Carlos; Moscato, Stefania; D’Alessandro, Delfo; Ugel, Stefano; Sartoris, Silvia; Bronte, Vincenzo; Boggi, Ugo; Campani, Daniela; Funel, Niccola; Moroni, Lorenzo; Danti, Serena

    2014-01-01

    We analyzed the interactions between human primary cells from pancreatic ductal adenocarcinoma (PDAC) and polymeric scaffolds to develop 3D cancer models useful for mimicking the biology of this tumor. Three scaffold types based on two biocompatible polymeric formulations, such as poly(vinyl alcohol)/gelatin (PVA/G) mixture and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) copolymer, were obtained via different techniques, namely, emulsion and freeze-drying, compression molding followed by salt leaching, and electrospinning. In this way, primary PDAC cells interfaced with different pore topographies, such as sponge-like pores of different shape and size or nanofiber interspaces. The aim of this study was to investigate the influence played by the scaffold architecture over cancerous cell growth and function. In all scaffolds, primary PDAC cells showed good viability and synthesized tumor-specific metalloproteinases (MMPs) such as MMP-2, and MMP-9. However, only sponge-like pores, obtained via emulsion-based and salt leaching-based techniques allowed for an organized cellular aggregation very similar to the native PDAC morphological structure. Differently, these cell clusters were not observed on PEOT/PBT electrospun scaffolds. MMP-2 and MMP-9, as active enzymes, resulted to be increased in PVA/G and PEOT/PBT sponges, respectively. These findings suggested that spongy scaffolds supported the generation of pancreatic tumor models with enhanced aggressiveness. In conclusion, primary PDAC cells showed diverse behaviors while interacting with different scaffold types that can be potentially exploited to create stage-specific pancreatic cancer models likely to provide new knowledge on the modulation and drug susceptibility of MMPs. PMID:25482337

  15. Distribution and Viability of Fetal and Adult Human Bone Marrow Stromal Cells in a Biaxial Rotating Vessel Bioreactor after Seeding on Polymeric 3D Additive Manufactured Scaffolds.

    PubMed

    Leferink, Anne M; Chng, Yhee-Cheng; van Blitterswijk, Clemens A; Moroni, Lorenzo

    2015-01-01

    One of the conventional approaches in tissue engineering is the use of scaffolds in combination with cells to obtain mechanically stable tissue constructs in vitro prior to implantation. Additive manufacturing by fused deposition modeling is a widely used technique to produce porous scaffolds with defined pore network, geometry, and therewith defined mechanical properties. Bone marrow-derived mesenchymal stromal cells (MSCs) are promising candidates for tissue engineering-based cell therapies due to their multipotent character. One of the hurdles to overcome when combining additive manufactured scaffolds with MSCs is the resulting heterogeneous cell distribution and limited cell proliferation capacity. In this study, we show that the use of a biaxial rotating bioreactor, after static culture of human fetal MSCs (hfMSCs) seeded on synthetic polymeric scaffolds, improved the homogeneity of cell and extracellular matrix distribution and increased the total cell number. Furthermore, we show that the relative mRNA expression levels of indicators for stemness and differentiation are not significantly changed upon this bioreactor culture, whereas static culture shows variations of several indicators for stemness and differentiation. The biaxial rotating bioreactor presented here offers a homogeneous distribution of hfMSCs, enabling studies on MSCs fate in additive manufactured scaffolds without inducing undesired differentiation. PMID:26557644

  16. Distribution and Viability of Fetal and Adult Human Bone Marrow Stromal Cells in a Biaxial Rotating Vessel Bioreactor after Seeding on Polymeric 3D Additive Manufactured Scaffolds

    PubMed Central

    Leferink, Anne M.; Chng, Yhee-Cheng; van Blitterswijk, Clemens A.; Moroni, Lorenzo

    2015-01-01

    One of the conventional approaches in tissue engineering is the use of scaffolds in combination with cells to obtain mechanically stable tissue constructs in vitro prior to implantation. Additive manufacturing by fused deposition modeling is a widely used technique to produce porous scaffolds with defined pore network, geometry, and therewith defined mechanical properties. Bone marrow-derived mesenchymal stromal cells (MSCs) are promising candidates for tissue engineering-based cell therapies due to their multipotent character. One of the hurdles to overcome when combining additive manufactured scaffolds with MSCs is the resulting heterogeneous cell distribution and limited cell proliferation capacity. In this study, we show that the use of a biaxial rotating bioreactor, after static culture of human fetal MSCs (hfMSCs) seeded on synthetic polymeric scaffolds, improved the homogeneity of cell and extracellular matrix distribution and increased the total cell number. Furthermore, we show that the relative mRNA expression levels of indicators for stemness and differentiation are not significantly changed upon this bioreactor culture, whereas static culture shows variations of several indicators for stemness and differentiation. The biaxial rotating bioreactor presented here offers a homogeneous distribution of hfMSCs, enabling studies on MSCs fate in additive manufactured scaffolds without inducing undesired differentiation. PMID:26557644

  17. Biological evaluation of porous aliphatic polyurethane/hydroxyapatite composite scaffolds for bone tissue engineering.

    PubMed

    Yang, Wanxun; Both, Sanne K; Zuo, Yi; Birgani, Zeinab Tahmasebi; Habibovic, Pamela; Li, Yubao; Jansen, John A; Yang, Fang

    2015-07-01

    Biomaterial scaffolds meant to function as supporting structures to osteogenic cells play a pivotal role in bone tissue engineering. Recently, we synthesized an aliphatic polyurethane (PU) scaffold via a foaming method using non-toxic components. Through this procedure a uniform interconnected porous structure was created. Furthermore, hydroxyapatite (HA) particles were introduced into this process to increase the bioactivity of the PU matrix. To evaluate the biological performances of these PU-based scaffolds, their influence on in vitro cellular behavior and in vivo bone forming capacity of the engineered cell-scaffold constructs was investigated in this study. A simulated body fluid test demonstrated that the incorporation of 40 wt % HA particles significantly promoted the biomineralization ability of the PU scaffolds. Enhanced in vitro proliferation and osteogenic differentiation of the seeded mesenchymal stem cells were also observed on the PU/HA composite. Next, the cell-scaffold constructs were implanted subcutaneously in a nude mice model. After 8 weeks, a considerable amount of vascularized bone tissue with initial marrow stroma development was generated in both PU and PU/HA40 scaffold. In conclusion, the PU/HA composite is a potential scaffold for bone regeneration applications. PMID:25370308

  18. Porous anodic aluminum oxide scaffolds; formation mechanisms and applications

    E-print Network

    Oh, Jihun

    2010-01-01

    Nanoporous anodic aluminium oxide (AAO) can be created with pores that self-assemble into ordered configurations. Nanostructured metal oxides have proven to be very useful as scaffolds for growth of nanowires and nanotubes ...

  19. A Porous Tissue Engineering Scaffold Selectively Degraded by Cell-Generated Reactive Oxygen Species

    PubMed Central

    Martin, John R.; Gupta, Mukesh K.; Page, Jonathan M.; Yu, Fang; Davidson, Jeffrey M.; Guelcher, Scott A.

    2014-01-01

    Biodegradable tissue engineering scaffolds are commonly fabricated from poly(lactide-co-glycolide) (PLGA) or similar polyesters that degrade by hydrolysis. PLGA hydrolysis generates acidic breakdown products that trigger an accelerated, autocatalytic degradation mechanism that can create mismatched rates of biomaterial breakdown and tissue formation. Reactive oxygen species (ROS) are key mediators of cell function in both health and disease, especially at sites of inflammation and tissue healing, and induction of inflammation and ROS are natural components of the in vivo response to biomaterial implantation. Thus, polymeric biomaterials that are selectively degraded by cell-generated ROS may have potential for creating tissue engineering scaffolds with better matched rates of tissue in-growth and cell-mediated scaffold biodegradation. To explore this approach, a series of poly(thioketal) (PTK) urethane (PTK-UR) biomaterial scaffolds were synthesized that degrade specifically by an ROS-dependent mechanism. PTK-UR scaffolds had significantly higher compressive moduli than analogous poly(ester urethane) (PEUR) scaffolds formed from hydrolytically-degradable ester-based diols (p < 0.05). Unlike PEUR scaffolds, the PTK-UR scaffolds were stable under aqueous conditions out to 25 weeks but were selectively degraded by ROS, indicating that their biodegradation would be exclusively cell-mediated. The in vitro oxidative degradation rates of the PTK-URs followed first-order degradation kinetics, were significantly dependent on PTK composition (p < 0.05), and correlated to ROS concentration. In subcutaneous rat wounds, PTK-UR scaffolds supported cellular infiltration and granulation tissue formation, followed first-order degradation kinetics over 7 weeks, and produced significantly greater stenting of subcutaneous wounds compared to PEUR scaffolds. These combined results indicate that ROS-degradable PTK-UR tissue engineering scaffolds have significant advantages over analogous polyester-based biomaterials and provide a robust, cell-degradable substrate for guiding new tissue formation. PMID:24491510

  20. Evaluation of 3D nano-macro porous bioactive glass scaffold for hard tissue engineering.

    PubMed

    Wang, S; Falk, M M; Rashad, A; Saad, M M; Marques, A C; Almeida, R M; Marei, M K; Jain, H

    2011-05-01

    Recently, nano-macro dual-porous, three-dimensional (3D) glass structures were developed for use as bioscaffolds for hard tissue regeneration, but there have been concerns regarding the interconnectivity and homogeneity of nanopores in the scaffolds, as well as the cytotoxicity of the environment deep inside due to limited fluid access. Therefore, mercury porosimetry, nitrogen absorption, and TEM have been used to characterize nanopore network of the scaffolds. In parallel, viability of MG 63 human osteosarcoma cells seeded on scaffold surface was investigated by fluorescence, confocal and electron microscopy methods. The results show that cells attach, migrate and penetrate inside the glass scaffold with high proliferation and viability rate. Additionally, scaffolds were implanted under the skin of a male New Zealand rabbit for in vivo animal test. Initial observations show the formation of new tissue with blood vessels and collagen fibers deep inside the implanted scaffolds with no obvious inflammatory reaction. Thus, the new nano-macro dual-porous glass structure could be a promising bioscaffold for use in regenerative medicine and tissue engineering for bone regeneration. PMID:21445655

  1. Osteoblast-like cell behavior on porous scaffolds based on poly(styrene) fibers.

    PubMed

    Serafim, Andrada; Mallet, Romain; Pascaretti-Grizon, Florence; Stancu, Izabela-Cristina; Chappard, Daniel

    2014-01-01

    Scaffolds of nonresorbable biomaterials can represent an interesting alternative for replacing large bone defects in some particular clinical cases with massive bone loss. Poly(styrene) microfibers were prepared by a dry spinning method. They were partially melted to provide 3D porous scaffolds. The quality of the material was assessed by Raman spectroscopy. Surface roughness was determined by atomic force microscopy and vertical interference microscopy. Saos-2 osteoblast-like cells were seeded on the surface of the fibers and left to proliferate. Cell morphology, evaluated by scanning electron microscopy, revealed that they can spread and elongate on the rough microfiber surface. Porous 3D scaffolds made of nonresorbable poly(styrene) fibers are cytocompatible biomaterials mimicking allogenic bone trabeculae and allowing the growth and development of osteoblast-like cells in vitro. PMID:25045688

  2. Heterogeneous minimal surface porous scaffold design using the distance field and radial basis functions.

    PubMed

    Yoo, Dongjin

    2012-06-01

    This paper presented an effective method for the 3D heterogeneous porous scaffold design of human tissue using triply periodic minimal surface (TPMS) internal pore architectures. First, an implicit solid representing the smooth 3D scalar field for the porosity distribution was reconstructed by interpolating the geometric positions of control points and porosity values defined at those points using an implicit interpolation algorithm based on the thin-plate radial basis function. After generating the implicit solid representing the smooth 3D scalar field for the porosity distribution, a functionally graded tissue scaffold with accurately controlled porosity distribution was designed using the TPMS-based unit cell libraries. Numerical results showed that the proposed scaffold design method has the potential benefits for accurately controlling the spatial porosity distribution within an arbitrarily shaped scaffold while keeping the advantage of the TPMS-based unit cell libraries. PMID:22487098

  3. Surface modification of biodegradable porous Mg bone scaffold using polycaprolactone/bioactive glass composite.

    PubMed

    Yazdimamaghani, Mostafa; Razavi, Mehdi; Vashaee, Daryoosh; Tayebi, Lobat

    2015-04-01

    A reduction in the degradation rate of magnesium (Mg) and its alloys is in high demand to enable these materials to be used in orthopedic applications. For this purpose, in this paper, a biocompatible polymeric layer reinforced with a bioactive ceramic made of polycaprolactone (PCL) and bioactive glass (BG) was applied on the surface of Mg scaffolds using dip-coating technique under low vacuum. The results indicated that the PCL-BG coated Mg scaffolds exhibited noticeably enhanced bioactivity compared to the uncoated scaffold. Moreover, the mechanical integrity of the Mg scaffolds was improved using the PCL-BG coating on the surface. The stable barrier property of the coatings effectively delayed the degradation activity of Mg scaffold substrates. Moreover, the coatings induced the formation of apatite layer on their surface after immersion in the SBF, which can enhance the biological bone in-growth and block the microcracks and pore channels in the coatings, thus prolonging their protective effect. Furthermore, it was shown that a three times increase in the concentration of PCL-BG noticeably improved the characteristics of scaffolds including their degradation resistance and mechanical stability. Since bioactivity, degradation resistance and mechanical integrity of a bone substitute are the key factors for repairing and healing fractured bones, we suggest that PCL-BG is a suitable coating material for surface modification of Mg scaffolds. PMID:25686970

  4. Correlation between properties and microstructure of laser sintered porous ?-tricalcium phosphate bone scaffolds

    NASA Astrophysics Data System (ADS)

    Shuai, Cijun; Feng, Pei; Zhang, Liyang; Gao, Chengde; Hu, Huanlong; Peng, Shuping; Min, Anjie

    2013-10-01

    A porous ?-tricalcium phosphate (?-TCP) bioceramic scaffold was successfully prepared with our homemade selective laser sintering system. Microstructure observation by a scanning electron microscope showed that the grains grew from 0.21 to 1.32 ?m with the decrease of laser scanning speed from 250 to 50 mm min-1. The mechanical properties increased mainly due to the improved apparent density when the laser scanning speed decreased to 150 mm min-1. When the scanning speed was further decreased, the grain size became larger and the mechanical properties severely decreased. The highest Vickers hardness and fracture toughness of the scaffold were 3.59 GPa and 1.16 MPa m1/2, respectively, when laser power was 11 W, spot size was 1 mm in diameter, layer thickness was 0.1-0.2 mm and laser scanning speed was 150 mm min-1. The biocompatibility of these scaffolds was assessed in vitro with MG63 osteoblast-like cells and human bone marrow mesenchymal stem cells. The results showed that all the prepared scaffolds are suitable for cell attachment and differentiation. Moreover, the smaller the grain size, the better the cell biocompatibility. The porous scaffold with a grain size of 0.71 ?m was immersed in a simulated body fluid for different days to assess the bioactivity. The surface of the scaffold was covered by a bone-like apatite layer, which indicated that the ?-TCP scaffold possesses good bioactivity. These discoveries demonstrated the evolution rule between grain microstructure and the properties that give a useful reference for the fabrication of ?-TCP bone scaffolds.

  5. Biodegradable CSMA/PECA/Graphene Porous Hybrid Scaffold for Cartilage Tissue Engineering

    PubMed Central

    Liao, JinFeng; Qu, Ying; Chu, BingYang; Zhang, XiaoNing; Qian, ZhiYong

    2015-01-01

    Owing to the limited repair capacity of articular cartilage, it is essential to develop tissue-engineered cartilage for patients suffering from joint disease and trauma. Herein, we prepared a novel hybrid scaffold composed of methacrylated chondroitin sulfate (CSMA), poly(ethylene glycol) methyl ether-?-caprolactone-acryloyl chloride (MPEG-PCL-AC, PECA was used as abbreviation for MPEG-PCL-AC) and graphene oxide (GO) and evaluated its potential application in cartilage tissue engineering. To mimic the natural extracellular matrix (ECM) of cartilage, the scaffold had an adequate pore size, porosity, swelling ability, compression modulus and conductivity. Cartilage cells contacted with the scaffold remained viable and showed growth potential. Furthermore, CSMA/PECA/GO scaffold was biocompatible and had a favorable degradation rate. In the cartilage tissue repair of rabbit, Micro-CT and histology observation showed the group of CSMA/PECA/GO scaffold with cellular supplementation had better chondrocyte morphology, integration, continuous subchondral bone, and much thicker newly formed cartilage compared with scaffold group and control group. Our results show that the CSMA/PECA/GO hybrid porous scaffold can be applied in articular cartilage tissue engineering and may have great potential to in other types of tissue engineering applications. PMID:25961959

  6. Microwave-assisted synthesis of porous chitosan-modified montmorillonite-hydroxyapatite composite scaffolds.

    PubMed

    Kar, Sumanta; Kaur, Tejinder; Thirugnanam, A

    2016-01-01

    In this study, a porous chitosan-organically modified montmorillonite-hydroxyapatite (CS-OM-HA) composite scaffold was developed by combining microwave irradiation and gas foaming method. Hydroxyapatite (HA) particles of size ?65nm were synthesized and characterized by X-ray diffraction (XRD) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The prepared composite scaffolds were characterized using ATR-FTIR, XRD, mercury intrusion porosimeter (MIP) and scanning electron microscopy (SEM) studies. The synergistic effect of HA and OM on the mechanical and in vitro biological properties (swelling, degradation, protein adsorption and bioactivity) of the composite scaffolds were evaluated. Swelling, degradation, mechanical property, bioactivity and protein adsorption studies of CS-OM-HA composite scaffolds have shown desirable results in comparison with the pure CS and CS-OM composite scaffolds. CS-OM-HA composite scaffolds were also found to be non-cytotoxic to MG 63 osteoblast cell lines. From the study, it can be concluded that the novel CS-OM-HA composite scaffold with improved mechanical and in vitro biological properties has wide potential in non-load bearing bone tissue engineering applications. PMID:26505953

  7. Biodegradable CSMA/PECA/Graphene Porous Hybrid Scaffold for Cartilage Tissue Engineering.

    PubMed

    Liao, JinFeng; Qu, Ying; Chu, BingYang; Zhang, XiaoNing; Qian, ZhiYong

    2015-01-01

    Owing to the limited repair capacity of articular cartilage, it is essential to develop tissue-engineered cartilage for patients suffering from joint disease and trauma. Herein, we prepared a novel hybrid scaffold composed of methacrylated chondroitin sulfate (CSMA), poly(ethylene glycol) methyl ether-?-caprolactone-acryloyl chloride (MPEG-PCL-AC, PECA was used as abbreviation for MPEG-PCL-AC) and graphene oxide (GO) and evaluated its potential application in cartilage tissue engineering. To mimic the natural extracellular matrix (ECM) of cartilage, the scaffold had an adequate pore size, porosity, swelling ability, compression modulus and conductivity. Cartilage cells contacted with the scaffold remained viable and showed growth potential. Furthermore, CSMA/PECA/GO scaffold was biocompatible and had a favorable degradation rate. In the cartilage tissue repair of rabbit, Micro-CT and histology observation showed the group of CSMA/PECA/GO scaffold with cellular supplementation had better chondrocyte morphology, integration, continuous subchondral bone, and much thicker newly formed cartilage compared with scaffold group and control group. Our results show that the CSMA/PECA/GO hybrid porous scaffold can be applied in articular cartilage tissue engineering and may have great potential to in other types of tissue engineering applications. PMID:25961959

  8. PLLA-collagen and PLLA-gelatin hybrid scaffolds with funnel-like porous structure for skin tissue engineering

    NASA Astrophysics Data System (ADS)

    Lu, Hongxu; Oh, Hwan Hee; Kawazoe, Naoki; Yamagishi, Kozo; Chen, Guoping

    2012-12-01

    In skin tissue engineering, a three-dimensional porous scaffold is necessary to support cell adhesion and proliferation and to guide cells moving into the repair area in the wound healing process. Structurally, the porous scaffold should have an open and interconnected porous architecture to facilitate homogenous cell distribution. Moreover, the scaffolds should be mechanically strong to protect deformation during the formation of new skin. In this study, the hybrid scaffolds were prepared by forming funnel-like collagen or gelatin sponge on a woven poly(l-lactic acid) (PLLA) mesh. The hybrid scaffolds combined the advantages of both collagen or gelatin (good cell-interactions) and PLLA mesh (high mechanical strength). The hybrid scaffolds were used to culture dermal fibroblasts for dermal tissue engineering. The funnel-like porous structure promoted homogeneous cell distribution and extracellular matrix production. The PLLA mesh reinforced the scaffold to avoid deformation. Subcutaneous implantation showed that the PLLA-collagen and PLLA-gelatin scaffolds promoted the regeneration of dermal tissue and epidermis and reduced contraction during the formation of new tissue. These results indicate that funnel-like hybrid scaffolds can be used for skin tissue regeneration.

  9. Nanoscalar modifications to polymeric tissue engineering scaffolds: Effect on cellular behavior

    NASA Astrophysics Data System (ADS)

    Powell, Heather M.

    Polymeric scaffolds provide a surface that can facilitate cell growth and tissue morphogenesis. Of particular interest is the role of nanoscalar features on cell behavior. Nanoscale topographies can be generated on two-dimensional polymeric substrates via reactive ion etching. The magnitude and morphology of the resultant surfaces can be tailored by varying the gas media, etching time and power used. Nanofibrillar surfaces were produced on polyethylene terephthalate films via oxygen-plasma etching. These nanofibrils were dimensionally similar to collagen fibers. Cells cultured on nanofibrillar surfaces were shown to have a disrupted cytoskeleton, lower levels of cell-substrate signaling, reduced strength of adhesion and an inhibition of lipid droplet coalescence. The results suggest that cells can detect nanoscalar surface topographies and alter their function in response to these environmental stimuli. While nanofibrillar surfaces can be considered pseudo-three dimensional, they cannot produce 3-D cell structures. Thus truly three dimensional scaffolds must be fabricated to determine the role of nanoscalar fibers on cell organization and function. Electrospinning was employed to generate 3-D meshes of polycaprolactone, a common biodegradable polymer. These nonwoven meshes were comprised of 500 nm fibers with an average pore size of 5 mum. In addition to forming mats of nonwoven fibers, electrospinning technology can also produce tubular scaffolds. These tubular scaffolds were seeded with human vascular smooth muscle cells and cultured for two days. After 2 days in culture, cells assumed a helical orientation around the lumen of the tube, an architecture which closely mimics natural blood vessels. Thus electrospun scaffolds facilitate the growth and organization of cell populations in a manner which imitates the natural tissue.

  10. Porous scaffold design using the distance field and triply periodic minimal surface models.

    PubMed

    Yoo, Dong J

    2011-11-01

    An effective method for the 3D porous scaffold design of human tissue is presented based on a hybrid method of distance field and triply periodic minimal surface (TPMS). By the creative application of traditional distance field algorithm into the Boolean operations of the anatomical model and TPMS-based unit cell library, an almost defects free porous scaffolds having the complicated micro-structure and high quality external surface faithful to a specific anatomic model can be easily obtained without the difficult and time-consuming trimming and re-meshing processes. After generating the distance fields for the given tissue model and required internal micro-structure, a series of simple modifications in distance fields enable us to obtain a complex porous scaffold. Experimental results show that the proposed scaffold design method has the potential to combine the perfectly interconnected pore networks based on the TPMS unit cell libraries and the given external geometry in a consistent framework irrespective of the complexity of the models. PMID:21798592

  11. Macro-scale Topology Optimization for Controlling Internal Shear Stress in a Porous Scaffold Bioreactor

    E-print Network

    K. Youssef; J. J. Mack; M. L. Iruela-Arispe; L. -S. Bouchard

    2012-01-09

    Shear stress is an important physical factor that regulates proliferation, migration and morphogenesis. In particular, the homeostasis of blood vessels is dependent on shear stress. To mimic this process ex vivo, efforts have been made to seed scaffolds with vascular and other cell types in the presence of growth factors and under pulsatile flow conditions. However, the resulting bioreactors lack information on shear stress and flow distributions within the scaffold. Consequently, it is difficult to interpret the effects of shear stress on cell function. Such knowledge would enable researchers to improve upon cell culture protocols. Recent work has focused on optimizing the microstructural parameters of the scaffold to fine tune the shear stress. In this study, we have adopted a different approach whereby flows are redirected throughout the bioreactor along channels patterned in the porous scaffold to yield shear stress distributions that are optimized for uniformity centered on a target value. A topology optimization algorithm coupled to computational fluid dynamics simulations was devised to this end. The channel topology in the porous scaffold was varied using a combination of genetic algorithm and fuzzy logic. The method is validated by experiments using magnetic resonance imaging (MRI) readouts of the flow field.

  12. Effects of surfactants on the microstructure of porous ceramic scaffolds fabricated by foaming for bone tissue engineering

    SciTech Connect

    Wang Xi; Ruan Jianming; Chen Qiyuan

    2009-06-03

    A porous scaffold comprising a {beta}-tricalcium phosphate matrix and bioactive glass powders was fabricated by foaming method and the effects of surfactants as foaming agent on microstructure of scaffolds were investigated. Foaming capacity and foam stability of different surfactants in water firstly were carried out to evaluate their foam properties. The porous structure and pore size distribution of the scaffolds were systematically characterized by scanning electron microscopy (SEM) and an optical microscopy connected to an image analyzer. The results showed that the foam stability of surfactant has more remarkable influence on their microstructure such as pore shape, size and interconnectivity than the foaming ability of one. Porous scaffolds fabricated using nonionic surfactant Tween 80 with large foam stability exhibited higher open and total porosities, and fully interconnected porous structure with a pore size of 750-850 {mu}m.

  13. Bioengineering strategies for polymeric scaffold for tissue engineering an aortic heart valve: an update.

    PubMed

    Morsi, Yosry S

    2014-09-01

    The occurrence of dysfunctional aortic valves is increasing every year, and current replacement heart valves, although having been shown to be clinically successful, are only short-term solutions and suffer from many agonizing long-term drawbacks. The tissue engineering of heart valves is recognized as one of the most promising answers for aortic valve disease therapy, but overcoming current shortcomings will require multidisciplinary efforts. The use of a polymeric scaffold to guide the growth of the tissue is the most common approach to generate a new tissue for an aortic heart valve. However, optimizing the design of the scaffold, in terms of biocompatibility, surface morphology for cell attachments and the correct rate of degradation is critical in creating a viable tissue-engineered aortic heart valve. This paper highlights the bioengineering strategies that need to be followed to construct a polymeric scaffold of sufficient mechanical integrity, with superior surface morphologies, that is capable of mimicking the valve dynamics in vivo. The current challenges and future directions of research for creating tissue-engineered aortic heart valves are also discussed. PMID:25262629

  14. MC3T3-E1 osteoblast attachment and proliferation on porous hydroxyapatite scaffolds fabricated with nanophase powder

    PubMed Central

    Smith, Ian O; McCabe, Laura R; Baumann, Melissa J

    2006-01-01

    Porous bone tissue engineering scaffolds were fabricated using both nano hydroxyapatite (nano HA) powder (20 nm average particle size) and micro HA powder (10 ?m average particle size), resulting in sintered scaffolds of 59 vol% porosity and 8.6±1.9 ?m average grain size and 72 vol% porosity and 588±55 nm average grain size, respectively. Scanning electron microscopy was used to measure both the grain size and pore size. MC3T3-E1 osteoblast (OB) attachment and proliferation on both nano HA and micro HA porous scaffolds were quantified. As expected, OB cell number was greater on nano HA scaffolds compared with similarly processed micro HA scaffolds 5 days after seeding, while OB attachment did not appear greater on the nano HA scaffolds (p<0.05). PMID:17722535

  15. Porous Hydroxyapatite Bioceramic Scaffolds for Drug Delivery and Bone Regeneration

    NASA Astrophysics Data System (ADS)

    Loca, Dagnija; Locs, Janis; Salma, Kristine; Gulbis, Juris; Salma, Ilze; Berzina-Cimdina, Liga

    2011-10-01

    The conventional methods of supplying a patient with pharmacologic active substances suffer from being very poorly selective, so that damage can occurs to the healthy tissues and organs, different from the intended target. In addition, high drug doses can be required to achieve the desired effect. An alternative approach is based on the use of implantable delivery tools, able to release the active substance in a controlled way. In the current research local drug delivery devices containing 8mg of gentamicin sulphate were prepared using custom developed vacuum impregnation technique. In vitro dissolution tests showed that gentamicin release was sustained for 12h. In order to decrease gentamicin release rate, biopolymer coatings were applied and coating structure investigated. The results showed that gentamicin release can be sustained for more than 70h for poly(epsilon-caprolactone) coated calcium phosphate scaffolds. From poly lactic acid and polyvinyl alcohol coated scaffolds gentamicin was released within 20h and 50h, respectively.

  16. Bioactivity and bone healing properties of biomimetic porous composite scaffold: in vitro and in vivo studies.

    PubMed

    Veronesi, Francesca; Giavaresi, Gianluca; Guarino, Vincenzo; Raucci, Maria Grazia; Sandri, Monica; Tampieri, Anna; Ambrosio, Luigi; Fini, Milena

    2015-09-01

    Tissue engineering (TE) represents a valid alternative to traditional surgical therapies for the management of bone defects that do not regenerate spontaneously. Scaffolds, one of the most important component of TE strategy, should be biocompatible, bioactive, osteoconductive, and osteoinductive. The aim of this study was to evaluate the biological properties and bone regeneration ability of a porous poly(?-caprolactone) (PCL) scaffold, incorporating MgCO3 -doped hydroxyapatite particles, uncoated (PCL_MgCHA) or coated by apatite-like crystals via biomimetic treatment (PCL_MgCHAB). It was observed that both scaffolds are not cytotoxic and, even if cell viability was similar on both scaffolds, PCL_MgCHAB showed higher alkaline phosphatase and collagen I (COLL I) production at day 7. PCL_MgCHA induced more tumor necrosis factor-? release than PCL_MgCHAB, while osteocalcin was produced less by both scaffolds up to 7 days and no significant differences were observed for transforming growth factor-? synthesis. The percentage of new bone trabeculae growth in wide defects carried out in rabbit femoral distal epiphyses was significantly higher in PCL_MgCHAB in comparison with PCL_MgCHA at 4 weeks and even more at 12 weeks after implantation. This study highlighted the role of a biomimetic composite scaffold in bone regeneration and lays the foundations for its future employment in the clinical practice. PMID:25689266

  17. Constitution and in vivo test of micro-porous tubular scaffold for esophageal tissue engineering.

    PubMed

    Hou, Lei; Jin, Jiachang; Lv, Jingjing; Chen, Ling; Zhu, Yabin; Liu, Xingyu

    2015-11-01

    Current clinical techniques in treating long-gap esophageal defects often lead to complications and high morbidity. Aiming at long-gap synthetic esophageal substitute, we had synthesized a biodegradable copolymer, poly(L-lactide-co-caprolactone) (PLLC), with low glass transition temperature. In this work, we developed a tubular PLLC porous scaffold using a self-designed tubular mold and thermal induced phase separation (TIPS) method. In order to enhance the interaction between tissue and scaffold, fibrin, a natural fibrous protein derived from blood fibrinogen, was coated on the scaffold circumferential surface. The fibrin density was measured to be 1.23?±?0.04?mg/cm(2). Primary epithelial cell culture demonstrated the improved in vitro biocompatibility. In animal study with partial scaffold implantation, in situ mucosa regeneration was observed along the degradation of the scaffold. These indicate that fibrin incorporated PLLC scaffold can greatly improve epithelial regeneration in esophagus repair, therefore serve as a good candidate for long-term evaluation of post-implantation at excision site. PMID:26208515

  18. Tantalum coating on porous Ti6Al4V scaffold using chemical vapor deposition and preliminary biological evaluation.

    PubMed

    Li, Xiang; Wang, Lin; Yu, Xiaoming; Feng, Yafei; Wang, Chengtao; Yang, Ke; Su, Daniel

    2013-07-01

    Porous tantalum (Ta), produced via chemical vapor deposition (CVD) of commercially pure Ta onto a vitreous carbon, is currently available for use in orthopedic applications. However, the relatively high manufacturing cost and the incapability to produce customized implant using medical image data have limited its application to gain widespread acceptance. In this study, Ta film was deposited on porous Ti6Al4V scaffolds using CVD technique. Digital microscopy and scanning electron microscopy indicated that the Ta coating evenly covered the entire scaffold structure. X-ray diffraction analysis showed that the coating consisted of ? and ? phases of Ta. Goat mesenchymal stem cells were seeded and cultured on the Ti6Al4V scaffolds with and without coating. The tetrazolium-based colorimetric assay exhibited better cell adhesion and proliferation on Ta-coated scaffolds compared with uncoated scaffolds. The porous scaffolds were subsequently implanted in goats for 12weeks. Histological analysis revealed similar bone formation around the periphery of the coated and uncoated implants, but bone ingrowth is better within the Ta-coated scaffolds. To demonstrate the ability of producing custom implant for clinical applications via this technology, we designed and fabricated a porous Ti6Al4V scaffold with segmental mandibular shape derived from patient computerized tomography data. PMID:23623123

  19. Preparation of Porous Scaffolds from Silk Fibroin Extracted from the Silk Gland of Bombyx mori (B. mori)

    PubMed Central

    Yang, Mingying; Shuai, Yajun; He, Wen; Min, Sijia; Zhu, Liangjun

    2012-01-01

    In order to use a simple and ecofriendly method to prepare porous silk scaffolds, aqueous silk fibroin solution (ASF) was extracted from silk gland of 7-day-old fifth instar larvae of Bombyx mori (B. mori). SDS-page analysis indicated that the obtained fibroin had a molecular weight higher than 200 kDa. The fabrication of porous scaffolds from ASF was achieved by using the freeze-drying method. The pore of porous scaffolds is homogenous and tends to become smaller with an increase in the concentration of ASF. Conversely, the porosity is decreased. The porous scaffolds show impressive compressive strength which can be as high as 6.9 ± 0.4 MPa. Furthermore, ASF has high cell adhesion and growth activity. It also exhibits high ALP activity. This implies that porous scaffolds prepared from ASF have biocompatibility. Therefore, the porous scaffolds prepared in this study have potential application in tissue engineering due to the impressive compressive strength and biocompatibility. PMID:22837725

  20. Simple method to generate and fabricate stochastic porous scaffolds.

    PubMed

    Yang, Nan; Gao, Lilan; Zhou, Kuntao

    2015-11-01

    Considerable effort has been made to generate regular porous structures (RPSs) using function-based methods, although little effort has been made for constructing stochastic porous structures (SPSs) using the same methods. In this short communication, we propose a straightforward method for SPS construction that is simple in terms of methodology and the operations used. Using our method, we can obtain a SPS with functionally graded, heterogeneous and interconnected pores, target pore size and porosity distributions, which are useful for applications in tissue engineering. The resulting SPS models can be directly fabricated using additive manufacturing (AM) techniques. PMID:26249613

  1. Enhanced osteogenesis in cocultures with human mesenchymal stem cells and endothelial cells on polymeric microfiber scaffolds.

    PubMed

    Gershovich, Julia G; Dahlin, Rebecca L; Kasper, F Kurtis; Mikos, Antonios G

    2013-12-01

    In this work, human mesenchymal stem cells (hMSCs) and their osteogenically precultured derivatives were directly cocultured with human umbilical vein endothelial cells (HUVECs) on electrospun three-dimensional poly(?-caprolactone) microfiber scaffolds to evaluate the coculture's effect on the generation of osteogenic constructs. Specifically, cells were cultured on scaffolds for up to 3 weeks, and the cellularity, alkaline phosphatase (ALP) activity, and bone-like matrix formation were assessed. Constructs with cocultures and monocultures had almost identical cellularity after the first week, however, lower cellularity was observed in cocultures compared to monocultures during the subsequent 2 weeks of culture. Scaffolds with cocultures showed a significantly higher ALP activity, glycosaminoglycan and collagen production, as well as greater calcium deposition over the course of study compared to monocultures of hMSCs. Furthermore, the osteogenic outcome was equally robust in cocultures containing osteogenically precultured and non-precultured hMSCs. The results demonstrate that the combination of MSC and HUVEC populations within a porous scaffold material under osteogenic culture conditions is an effective strategy to promote osteogenesis. PMID:23799306

  2. Direct Ink Writing of Highly Porous and Strong Glass Scaffolds for Load-bearing Bone Defects Repair and Regeneration

    PubMed Central

    Fu, Qiang; Saiz, Eduardo; Tomsia, Antoni P.

    2011-01-01

    The quest for synthetic materials to repair load-bearing bone lost because of trauma, cancer, or congenital bone defects requires development of porous and high-performance scaffolds with exceptional mechanical strength. However, the low mechanical strength of porous bioactive ceramic and glass scaffolds, compared with that of human cortical bone, has limited their use for these applications. In the present work, bioactive 6P53B glass scaffolds with superior mechanical strength were fabricated using a direct ink writing technique. The rheological properties of Pluronic® F-127 (referred to hereafter simply as F-127) hydrogel-based inkswere optimized for the printing of features as fine as 30 ?m and of the three-dimensional scaffolds. The mechanical strength and in vitro degradation of the scaffolds were assessed in a simulated body fluid (SBF). The sintered glass scaffolds show a compressive strength (136 ± 22 MPa) comparable to that of human cortical bone (100-150 MPa), while the porosity (60%) is in the range of that of trabecular bone (50-90%).The strength is ~100 times that of polymer scaffolds and 4–5 times that of ceramic and glass scaffolds with comparable porosities. Despite the strength decrease resulting from weight loss during immersion in an SBF, the value (77 MPa) is still far above that of trabecular bone after three weeks. The ability to create both porous and strong structures opens a new avenue for fabricating scaffolds for load-bearing bone defect repair and regeneration. PMID:21745606

  3. High resolution x-ray imaging of dynamic solute transport in cyclically deformed porous tissue scaffolds

    NASA Astrophysics Data System (ADS)

    Op Den Buijs, Jorn; Lee, Kee-Won; Jorgensen, Steven M.; Wang, Shanfeng; Yaszemski, Michael J.; Ritman, Erik L.

    2008-03-01

    The objective was to develop a method for high-resolution imaging of dynamic solute transport in cyclically deforming porous scaffolds for tissue engineering applications. A flexible cubic scaffold with single cylindrical channel was fabricated from a biodegradable polymer blend using a combined 3D printing and injection molding technique. The scaffold was attached to the bottom of a fluid reservoir mounted underneath a compression apparatus placed inside the X-ray scanner. The scaffold was positioned with the channel axis perpendicular to the X-ray beam. The container was filled with glycerin, and a solution of the contrast agent sodium iodide (NaI) in glycerin was injected into the scaffold channel. Intervals of compression cycles (14.5 +/- 2.1 % compression at 1.0 Hz) were applied to the top face of the scaffold. After each interval the compression was temporarily paused to obtain a two-dimensional image at 20 ?m pixel resolution. A series of images was also obtained without application of the compression cycles to quantify the effect of passive diffusional removal of NaI from the channel. The average NaI concentration in the channel decreased by 82% after 300 cycles (5 min.) of compression, by 40% after 60 min. of passive removal. Spatial profiles of the NaI concentration along the channel axis indicated that compression-induced transport preferentially removed the contrast agent at the pore openings. We conclude that convective transport induced by cyclic mechanical deformation of artificial tissue scaffolds could significantly contribute to the rate and depth of nutrient transport inside the scaffold, as compared to slow diffusive transport alone.

  4. Development and Characterization of Novel Porous 3D Alginate-Cockle Shell Powder Nanobiocomposite Bone Scaffold

    PubMed Central

    Bharatham, B. Hemabarathy; Abu Bakar, Md. Zuki; Perimal, Enoch Kumar; Yusof, Loqman Mohamed; Hamid, Muhajir

    2014-01-01

    A novel porous three-dimensional bone scaffold was developed using a natural polymer (alginate/Alg) in combination with a naturally obtained biomineral (nano cockle shell powder/nCP) through lyophilization techniques. The scaffold was developed in varying composition mixture of Alg-nCP and characterized using various evaluation techniques as well as preliminary in vitro studies on MG63 human osteoblast cells. Morphological observations using SEM revealed variations in structures with the use of different Alg-nCP composition ratios. All the developed scaffolds showed a porous structure with pore sizes ideal for facilitating new bone growth; however, not all combination mixtures showed subsequent favorable characteristics to be used for biological applications. Scaffolds produced using the combination mixture of 40% Alg and 60% nCP produced significantly promising results in terms of mechanical strength, degradation rate, and increased cell proliferation rates making it potentially the optimum composition mixture of Alg-nCP with future application prospects. PMID:25110655

  5. Development and characterization of novel porous 3D alginate-cockle shell powder nanobiocomposite bone scaffold.

    PubMed

    Bharatham, B Hemabarathy; Abu Bakar, Md Zuki; Perimal, Enoch Kumar; Yusof, Loqman Mohamed; Hamid, Muhajir

    2014-01-01

    A novel porous three-dimensional bone scaffold was developed using a natural polymer (alginate/Alg) in combination with a naturally obtained biomineral (nano cockle shell powder/nCP) through lyophilization techniques. The scaffold was developed in varying composition mixture of Alg-nCP and characterized using various evaluation techniques as well as preliminary in vitro studies on MG63 human osteoblast cells. Morphological observations using SEM revealed variations in structures with the use of different Alg-nCP composition ratios. All the developed scaffolds showed a porous structure with pore sizes ideal for facilitating new bone growth; however, not all combination mixtures showed subsequent favorable characteristics to be used for biological applications. Scaffolds produced using the combination mixture of 40% Alg and 60% nCP produced significantly promising results in terms of mechanical strength, degradation rate, and increased cell proliferation rates making it potentially the optimum composition mixture of Alg-nCP with future application prospects. PMID:25110655

  6. Performance of PRP Associated with Porous Chitosan as a Composite Scaffold for Regenerative Medicine

    PubMed Central

    Shimojo, Andréa Arruda Martins; Perez, Amanda Gomes Marcelino; Galdames, Sofia Elisa Moraga; Brissac, Isabela Cambraia de Souza; Santana, Maria Helena Andrade

    2015-01-01

    This study aimed to evaluate the in vitro performance of activated platelet-rich plasma associated with porous sponges of chitosan as a composite scaffold for proliferation and osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells. The sponges were prepared by controlled freezing (?20, ?80, or ?196°C) and lyophilization of chitosan solutions (1, 2, or 3% w/v). The platelet-rich plasma was obtained from controlled centrifugation of whole blood and activated with calcium and autologous serum. The composite scaffolds were prepared by embedding the sponges with the activated platelet-rich plasma. The results showed the performance of the scaffolds was superior to that of activated platelet-rich plasma alone, in terms of delaying the release of growth factors and increased proliferation of the stem cells. The best preparation conditions of chitosan composite scaffolds that coordinated the physicochemical and mechanical properties and cell proliferation were 3% (w/v) chitosan and a ?20°C freezing temperature, while ?196°C favored osteogenic differentiation. Although the composite scaffolds are promising for regenerative medicine, the structures require stabilization to prevent the collapse observed after five days. PMID:25821851

  7. New paradigms in internal architecture design and freeform fabrication of tissue engineering porous scaffolds.

    PubMed

    Yoo, Dongjin

    2012-07-01

    Advanced additive manufacture (AM) techniques are now being developed to fabricate scaffolds with controlled internal pore architectures in the field of tissue engineering. In general, these techniques use a hybrid method which combines computer-aided design (CAD) with computer-aided manufacturing (CAM) tools to design and fabricate complicated three-dimensional (3D) scaffold models. The mathematical descriptions of micro-architectures along with the macro-structures of the 3D scaffold models are limited by current CAD technologies as well as by the difficulty of transferring the designed digital models to standard formats for fabrication. To overcome these difficulties, we have developed an efficient internal pore architecture design system based on triply periodic minimal surface (TPMS) unit cell libraries and associated computational methods to assemble TPMS unit cells into an entire scaffold model. In addition, we have developed a process planning technique based on TPMS internal architecture pattern of unit cells to generate tool paths for freeform fabrication of tissue engineering porous scaffolds. PMID:22721938

  8. Fabrication of porous titanium scaffolds by stack sintering of microporous titanium spheres produced with centrifugal granulation technology.

    PubMed

    Chen, Hongjie; Wang, Chunli; Zhu, Xiangdong; Zhang, Kai; Fan, Yujiang; Zhang, Xingdong

    2014-10-01

    Microporosity plays a key role in bioactivity and osteoinductivity of a biomaterial scaffold. A simple new approach to fabricating load-bearing porous titanium (Ti) scaffolds with uniform porous structure, highly controllable pore size and excellent biocompatibility was developed in the present study. This method was based on stack sintering of microporous Ti spheres produced with centrifugal granulation of commercial Ti powders. Macropores (180.0-341.8 ?m) and micropores (6.1-11.8 ?m) of the scaffolds were dependent on the sizes of the Ti spheres and the Ti powders, respectively. The compressive strength of the scaffolds (83.4-108.9 MPa) was high enough for the repair of load-bearing bone defects. Besides, the abundant micropores occurred on the rough and convex surface of the Ti spheres in the scaffolds were more favorable for adsorption of serum proteins, and thus promoted the growth of mesenchymal stem cells (MSCs). PMID:25175203

  9. Porous biphasic scaffolds and coatings for biomedical applications via morphology transition of nanorods

    NASA Astrophysics Data System (ADS)

    Viswanath, B.; Ravishankar, N.

    2007-11-01

    Scaffolds based on calcium phosphates are ideally suited for bone tissue engineering applications. Here, we report a novel method to prepare biphasic calcium phosphate blocks and porous coatings via a morphology transition of anisotropic nanostructured hydroxyapatite. Size-controlled hydroxyapatite nanowhiskers have been synthesized by a hydrothermal method. Heating an assembly of these nanowhiskers leads to the formation of porous biphasic structures in a single step. Structural and microstructural characterization has been carried out using XRD, SEM and TEM. A BET surface area analyzer has been used to determine the surface area resulting from the porous structure. The formation mechanism of these structures is discussed. The present method also opens up possibilities to synthesize nanoporous structures of other functional inorganic materials.

  10. A biodegradable porous composite scaffold of PGA/beta-TCP for bone tissue engineering.

    PubMed

    Cao, Hong; Kuboyama, Noboru

    2010-02-01

    Polyglycolic acid (PGA) and beta-tricalcium phosphate (beta-TCP) each have many applications as tissue repair materials. In this study, three-dimensional (3D) porous composite scaffolds of PGA/beta-TCP (in 1:1 and 1:3 weight ratios) were fabricated using the solvent casting and particulate leaching method. PGA/beta-TCP scaffolds with high porosity, interconnected 3D pores and rough surfaces were obtained and were observed using scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). The PGA/beta-TCP scaffolds were investigated during the repair of critical bone defects (3 mm diameter, 2 mm depth) in rat femoral medial-epicondyles, compared with hydroxylapatite (HAP) and no implant as controls. Quantitative imageology analysis (volume and density of new bone) and qualitative histological evaluations (hematoxylin and eosin staining; tartrate-resistant acid phosphatase-hematoxylin counterstaining) were characterized using in vivo micro-CT images and histological sections at 0, 14, 30 and 90 days after surgery. Significant differences of all variables were tested by multivariate analysis (p<0.05). The results showed that the bone reformation by using the PGA/beta-TCP scaffolds began within 14 days of surgery, and were healing well at 30 days after surgery. By 90 days after surgery, the bone replacement was almost completed and presented a healthy bone appearance. The new bone mineral densities (mg/cm(3)) with HAP, PGA/beta-TCP (1:1) and PGA/beta-TCP (1:3) at 90 days after surgery were: 390.4+/-18.1, 563.8+/-26.9 and 606.3+/-26.9, respectively. The new bone mineral density with the PGA/beta-TCP scaffold was higher than with HAP (p<0.001), and with the PGA/beta-TCP (1:3) scaffold was higher than with the PGA/beta-TCP (1:1) scaffold at each time examined (p<0.05). The biodegradation percents (%) of HAP, PGA/beta-TCP (1:1) and PGA/beta-TCP (1:3) at 90 days after surgery were: 35.1+/-5.5, 99.0+/-1.0 and 96.2+/-3.3, respectively. The biodegradation percents of the PGA/beta-TCP scaffolds were higher than HAP at each time examined (p<0.01), and matched the osteogenesis rates. The PGA/beta-TCP scaffolds were almost replaced by new growing bone within 90 days after surgery. Thus the PGA/beta-TCP composite scaffold, especially weight ratio 1:3, exhibited a strong ability for osteogenesis, mineralization and biodegradation for bone replacement. PMID:19800045

  11. Compensation of spherical aberration influences for two-photon polymerization patterning of large 3D scaffolds

    NASA Astrophysics Data System (ADS)

    Stichel, T.; Hecht, B.; Houbertz, R.; Sextl, G.

    2015-10-01

    Two-photon polymerization using femtosecond laser pulses at a wavelength of 515 nm is used for three-dimensional patterning of photosensitive, biocompatible inorganic-organic hybrid polymers (ORMOCER®s). In order to fabricate millimeter-sized biomedical scaffold structures with interconnected pores, medium numerical aperture air objectives with long working distances are applied which allow voxel lengths of several micrometers and thus the solidification of large scaffolds in an adequate time. It is demonstrated that during processing the refraction of the focused laser beam at the air/material interface leads to strong spherical aberration which decreases the peak intensity of the focal point spread function along with shifting and severely extending the focal region in the direction of the beam propagation. These effects clearly decrease the structure integrity, homogeneity and the structure details and therefore are minimized by applying a positioning and laser power adaptation throughout the fabrication process. The results will be discussed with respect to the resulting structural homogeneity and its application as biomedical scaffold.

  12. Direct fabrication of high-resolution three-dimensional polymeric scaffolds using electrohydrodynamic hot jet plotting

    NASA Astrophysics Data System (ADS)

    Wei, Chuang; Dong, Jingyan

    2013-02-01

    This paper presents the direct three-dimensional (3D) fabrication of polymer scaffolds with sub-10 µm structures using electrohydrodynamic jet (EHD-jet) plotting of melted thermoplastic polymers. Traditional extrusion-based fabrication approaches of 3D periodic porous structures are very limited in their resolution, due to the excessive pressure requirement for extruding highly viscous thermoplastic polymers. EHD-jet printing has become a high-resolution alternative to other forms of nozzle deposition-based fabrication approaches by generating micro-scale liquid droplets or a fine jet through the application of a large electrical voltage between the nozzle and the substrate. In this study, we successfully apply EHD-jet plotting technology with melted biodegradable polymer (polycaprolactone, or PCL) for the fabrication of 2D patterns and 3D periodic porous scaffold structures in potential tissue engineering applications. Process conditions (e.g. electrical voltage, pressure, plotting speed) have been thoroughly investigated to achieve reliable jet printing of fine filaments. We have demonstrated for the first time that the EHD-jet plotting process is capable of the fabrication of 3D periodic structures with sub-10 µm resolution, which has great potential in advanced biomedical applications, such as cell alignment and guidance.

  13. Porous Shape Memory Polymers

    PubMed Central

    Hearon, Keith; Singhal, Pooja; Horn, John; Small, Ward; Olsovsky, Cory; Maitland, Kristen C.; Wilson, Thomas S.; Maitland, Duncan J.

    2013-01-01

    Porous shape memory polymers (SMPs) include foams, scaffolds, meshes, and other polymeric substrates that possess porous three-dimensional macrostructures. Porous SMPs exhibit active structural and volumetric transformations and have driven investigations in fields ranging from biomedical engineering to aerospace engineering to the clothing industry. The present review article examines recent developments in porous SMPs, with focus given to structural and chemical classification, methods of characterization, and applications. We conclude that the current body of literature presents porous SMPs as highly interesting smart materials with potential for industrial use. PMID:23646038

  14. Facile fabrication of hierarchical porous resins via high internal phase emulsion and polymeric porogen

    NASA Astrophysics Data System (ADS)

    Ma, Libin; Luo, Xiaogang; Cai, Ning; Xue, Yanan; Zhu, San; Fu, Zhen; Yu, Faquan

    2014-06-01

    To achieve the dual features of fast oil absorption rate and high oil absorbency for the practical application in emergency treatment of spilled chemical pollutants, hierarchical porous resins were synthesized. The polymerization of high internal phase emulsion was applied to fabricate the porous structure for the purpose of high oil absorbency. Polymeric porogens were proposed to adjust the second-order or interconnected pore structure for fast oil absorption rate. SEM revealed the hierarchical porous structure. Molecular weight and dose of polymeric porogen were investigated for the effect on the formation of porous structure and absorption features. Optimized resins have 31.5 g/g or 17.1 g/g absorbency for chloroform and toluene, respectively, and only 5 min is needed to reach their saturation absorption. Besides, the porous resins demonstrated high oil retention under pressure. The absorption/desorption cycling results revealed the high repeatability of recovered resins. All these tests predicted the potential applications of porous resins of this kind particularly in the emergency treatment of oil and chemical pollution.

  15. Conductive porous scaffolds as potential neural interface materials.

    SciTech Connect

    Hedberg-Dirk, Elizabeth L.; Cicotte, Kirsten N.; Buerger, Stephen P.; Reece, Gregory; Dirk, Shawn M.; Lin, Patrick P.

    2011-11-01

    Our overall intent is to develop improved prosthetic devices with the use of nerve interfaces through which transected nerves may grow, such that small groups of nerve fibers come into close contact with electrode sites, each of which is connected to electronics external to the interface. These interfaces must be physically structured to allow nerve fibers to grow through them, either by being porous or by including specific channels for the axons. They must be mechanically compatible with nerves such that they promote growth and do not harm the nervous system, and biocompatible to promote nerve fiber growth and to allow close integration with biological tissue. They must exhibit selective and structured conductivity to allow the connection of electrode sites with external circuitry, and electrical properties must be tuned to enable the transmission of neural signals. Finally, the interfaces must be capable of being physically connected to external circuitry, e.g. through attached wires. We have utilized electrospinning as a tool to create conductive, porous networks of non-woven biocompatible fibers in order to meet the materials requirements for the neural interface. The biocompatible fibers were based on the known biocompatible material poly(dimethyl siloxane) (PDMS) as well as a newer biomaterial developed in our laboratories, poly(butylene fumarate) (PBF). Both of the polymers cannot be electrospun using conventional electrospinning techniques due to their low glass transition temperatures, so in situ crosslinking methodologies were developed to facilitate micro- and nano-fiber formation during electrospinning. The conductivity of the electrospun fiber mats was controlled by controlling the loading with multi-walled carbon nanotubes (MWNTs). Fabrication, electrical and materials characterization will be discussed along with initial in vivo experimental results.

  16. Mechanical properties of highly porous PDLLA/Bioglass composite foams as scaffolds for bone tissue engineering.

    PubMed

    Blaker, J J; Maquet, V; Jérôme, R; Boccaccini, A R; Nazhat, S N

    2005-11-01

    This study developed highly porous degradable composites as potential scaffolds for bone tissue engineering. These scaffolds consisted of poly-D,L-lactic acid filled with 2 and 15 vol.% of 45S5 Bioglass particles and were produced via thermally induced solid-liquid phase separation and subsequent solvent sublimation. The scaffolds had a bimodal and anisotropic pore structure, with tubular macro-pores of approximately 100 microm in diameter, and with interconnected micro-pores of approximately 10-50 microm in diameter. Quasi-static and thermal dynamic mechanical analysis carried out in compression along with thermogravimetric analysis was used to investigate the effect of Bioglass on the properties of the foams. Quasi-static compression testing demonstrated mechanical anisotropy concomitant with the direction of the macro-pores. An analytical modelling approach was applied, which demonstrated that the presence of Bioglass did not significantly alter the porous architecture of these foams and reflected the mechanical anisotropy which was congruent with the scanning electron microscopy investigation. This study found that the Ishai-Cohen and Gibson-Ashby models can be combined to predict the compressive modulus of the composite foams. The modulus and density of these complex foams are related by a power-law function with an exponent between 2 and 3. PMID:16701845

  17. 3D Printing Bioceramic Porous Scaffolds with Good Mechanical Property and Cell Affinity.

    PubMed

    Chang, Chih-Hao; Lin, Chih-Yang; Liu, Fwu-Hsing; Chen, Mark Hung-Chih; Lin, Chun-Pin; Ho, Hong-Nerng; Liao, Yunn-Shiuan

    2015-01-01

    Artificial bone grafting is widely used in current orthopedic surgery for bone defect problems. Unfortunately, surgeons remain unsatisfied with the current commercially available products. One of the major complaints is that these products cannot provide sufficient mechanical strength to support the human skeletal structure. In this study, we aimed to develop a bone scaffold with better mechanical property and good cell affinity by 3D printing (3DP) techniques. A self-developed 3D printer with laser-aided gelling (LAG) process was used to fabricate bioceramic scaffolds with inter-porous structures. To improve the mechanical property of the bioceramic parts after heating, CaCO3 was added to the silica ceramic slurry. CaCO3 was blended into a homogenous SiO2-sol dispersion at weight ratios varying from 0/100 to 5/95 to 9/91 (w/w). Bi-component CaCO3/SiO2-sol was prepared as a biocomposite for the 3DP scaffold. The well-mixed biocomposite was used to fabricate the bioceramic green part using the LAG method. The varied scaffolds were sintered at different temperatures ranging from 900 to 1500°C, and the mechanical property was subsequently analyzed. The scaffolds showed good property with the composite ratio of 5:95 CaCO3:SiO2 at a sintering temperature of 1300°C. The compressive strength was 47 MPa, and the porosity was 34%. The topography of the sintered 3DP bioceramic scaffold was examined by SEM, EDS and XRD. The silica bioceramic presented no cytotoxicity and good MG-63 osteoblast-like cell affinity, demonstrating good biocompatibility. Therefore, the new silica biocomposite is viable for fabricating 3DP bone bioceramics with improved mechanical property and good cell affinity. PMID:26618362

  18. 3D Printing Bioceramic Porous Scaffolds with Good Mechanical Property and Cell Affinity

    PubMed Central

    Chang, Chih-Hao; Lin, Chih-Yang; Liu, Fwu-Hsing; Chen, Mark Hung-Chih; Lin, Chun-Pin; Ho, Hong-Nerng; Liao, Yunn-Shiuan

    2015-01-01

    Artificial bone grafting is widely used in current orthopedic surgery for bone defect problems. Unfortunately, surgeons remain unsatisfied with the current commercially available products. One of the major complaints is that these products cannot provide sufficient mechanical strength to support the human skeletal structure. In this study, we aimed to develop a bone scaffold with better mechanical property and good cell affinity by 3D printing (3DP) techniques. A self-developed 3D printer with laser-aided gelling (LAG) process was used to fabricate bioceramic scaffolds with inter-porous structures. To improve the mechanical property of the bioceramic parts after heating, CaCO3 was added to the silica ceramic slurry. CaCO3 was blended into a homogenous SiO2-sol dispersion at weight ratios varying from 0/100 to 5/95 to 9/91 (w/w). Bi-component CaCO3/SiO2-sol was prepared as a biocomposite for the 3DP scaffold. The well-mixed biocomposite was used to fabricate the bioceramic green part using the LAG method. The varied scaffolds were sintered at different temperatures ranging from 900 to 1500°C, and the mechanical property was subsequently analyzed. The scaffolds showed good property with the composite ratio of 5:95 CaCO3:SiO2 at a sintering temperature of 1300°C. The compressive strength was 47 MPa, and the porosity was 34%. The topography of the sintered 3DP bioceramic scaffold was examined by SEM, EDS and XRD. The silica bioceramic presented no cytotoxicity and good MG-63 osteoblast-like cell affinity, demonstrating good biocompatibility. Therefore, the new silica biocomposite is viable for fabricating 3DP bone bioceramics with improved mechanical property and good cell affinity. PMID:26618362

  19. Characterization of Silk Fibroin/Chitosan 3D Porous Scaffold and In Vitro Cytology

    PubMed Central

    Zeng, Shuguang; Liu, Lei; Shi, Yong; Qiu, Junqi; Fang, Wei; Rong, Mingdeng; Guo, Zehong; Gao, Wenfeng

    2015-01-01

    Bone tissue engineering is a powerful tool to treat bone defects caused by trauma, infection, tumors and other factors. Both silk fibroin (SF) and chitosan (CS) are non-toxic and have good biocompatibility, but are poor biological scaffolds when used alone. In this study, the microscopic structure and related properties of SF/CS composite scaffolds with different component ratios were examined. The scaffold material most suitable for osteoblast growth was determined, and these results offer an experimental basis for the future reconstruction of bone defects. First, via freeze-drying and chemical crosslinking methods, SF/CS composites with different component ratios were prepared and their structure was characterized. Changes in the internal structure of the SF and CS mixture were observed, confirming that the mutual modification between the two components was complete and stable. The internal structure of the composite material was porous and three-dimensional with a porosity above 90%. We next studied the pore size, swelling ratio, water absorption ratio, degradation and in vitro cell proliferation. For the 40% SF-60% CS group, the pore size of the scaffold was suitable for the growth of osteoblasts, and the rate of degradation was steady. This favors the early adhesion, growth and proliferation of MG-63 cells. In addition to good biocompatibility and satisfactory cell affinity, this material promotes the secretion of extracellular matrix materials by osteoblasts. Thus, 40% SF-60% CS is a good material for bone tissue engineering. PMID:26083846

  20. Direct writing of porous tissue scaffolds based on Vaseline-doped hydroxyapatite inks

    NASA Astrophysics Data System (ADS)

    Li, Ya-Yun; Li, Long-Tu; Li, Bo

    2015-05-01

    A novel type of 40 vol.% hydroxyapatite (HAp), Ca10(PO4)6(OH)2, suspension doped with Vaseline was developed, and porous three-dimensional (3D) scaffolds were fabricated by using a direct ink writing (DIW) method. The preparation of the HAp inks and the principles of the DIW technique were investigated. The microporosity of the scaffold wall increased after introducing the Vaseline, whereas macroporosity can be produced by varying the DIW technique. The micromorphology test results show that the samples sintered at 1150°C for 2 h formed ceramics with a set amount of pores, which benefit cell growth by providing more locations for cells to attach and proliferate. Under a microscope, the proliferations of human liver carcinoma cell line (HepG2) cells can be observed on the 3D HAp scaffolds. The DIW method has the advantages of a rapid process, ease of design and high precision control, potentially inspiring the design and application of biomaterials and scaffolds.

  1. Porous Scaffolds Support Extrahepatic Human Islet Transplantation, Engraftment and Function in Mice

    PubMed Central

    Gibly, Romie F.; Zhang, Xiaomin; Lowe, William L.; Shea, Lonnie D.

    2013-01-01

    Islet transplantation as a therapy or cure for type 1 diabetes has significant promise but has been limited by islet mass requirements and long-term graft failure. The intrahepatic and intravascular site may be responsible for significant loss of transplanted islets. Nonencapsulating biomaterial scaffolds provide a strategy for architecturally defining and modulating extrahepatic sites beyond the endogenous milieu to enhance islet survival and function. We utilized scaffolds to transplant human islets into the intraperitoneal fat of immunodeficient mice. A smaller human islet mass than previously reported reversed murine diabetes and restored glycemic control at human blood glucose levels. Graft function was highly dependent on the islet number transplanted and directly correlated to islet viability, as determined by the ATP-to-DNA ratio. Islets engrafted and revascularized in host tissue, and glucose tolerance testing indicated performance equivalent to healthy mice. Addition of extracellular matrix, specifically collagen IV, to scaffold surfaces improved graft function compared to serum-supplemented media. Porous scaffolds can facilitate efficient human islet transplantation and provide a platform for modulating the islet microenvironment, in ways not possible with current clinical strategies, to enhance islet engraftment and function. PMID:22507300

  2. 3D printing of porous hydroxyapatite scaffolds intended for use in bone tissue engineering applications.

    PubMed

    Cox, Sophie C; Thornby, John A; Gibbons, Gregory J; Williams, Mark A; Mallick, Kajal K

    2015-02-01

    A systematic characterisation of bone tissue scaffolds fabricated via 3D printing from hydroxyapatite (HA) and poly(vinyl)alcohol (PVOH) composite powders is presented. Flowability of HA:PVOH precursor materials was observed to affect mechanical stability, microstructure and porosity of 3D printed scaffolds. Anisotropic behaviour of constructs and part failure at the boundaries of interlayer bonds was highlighted by compressive strength testing. A trade-off between the ability to facilitate removal of PVOH thermal degradation products during sintering and the compressive strength of green parts was revealed. The ultimate compressive strength of 55% porous green scaffolds printed along the Y-axis and dried in a vacuum oven for 6h was 0.88 ± 0.02 MPa. Critically, the pores of 3D printed constructs could be user designed, ensuring bulk interconnectivity, and the imperfect packing of powder particles created an inherent surface roughness and non-designed porosity within the scaffold. These features are considered promising since they are known to facilitate osteoconduction and osteointegration in-vivo. Characterisation techniques utilised in this study include two funnel flow tests, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), compressive strength testing and computed tomography (CT). PMID:25492194

  3. Hydrothermal fabrication of hydroxyapatite/chitosan/carbon porous scaffolds for bone tissue engineering.

    PubMed

    Long, Teng; Liu, Yu-Tai; Tang, Sha; Sun, Jin-Liang; Guo, Ya-Ping; Zhu, Zhen-An

    2014-11-01

    Porous carbon fiber felts (PCFFs) have great applications in orthopedic surgery because of the strong mechanical strength, low density, high stability, and porous structure, but they are biologically inert. To improve their biological properties, we developed, for the first time, the hydroxyapatite (HA)/chitosan/carbon porous scaffolds (HCCPs). HA/chitosan nanohybrid coatings have been fabricated on PCFFs according to the following stages: (i) deposition of chitosan/calcium phosphate precursors on PCFFs; and (ii) hydrothermal transformation of the calcium phosphate precursors in chitosan matrix into HA nanocrystals. The scanning electron microscopy images indicate that PCFFs are uniformly covered with elongated HA nanoplates and chitosan, and the macropores in PCFFs still remain. Interestingly, the calcium-deficient HA crystals exist as plate-like shapes with thickness of 10-18 nm, width of 30-40 nm, and length of 80-120 nm, which are similar to the biological apatite. The HA in HCCPs is similar to the mineral of natural bone in chemical composition, crystallinity, and morphology. As compared with PCFFs, HCCPs exhibit higher in vitro bioactivity and biocompatibility because of the presence of the HA/chitosan nanohybrid coatings. HCCPs not only promote the formation of bone-like apatite in simulated body fluid, but also improve the adhesion, spreading, and proliferation of human bone marrow stromal cells. Hence, HCCPs have great potentials as scaffold materials for bone tissue engineering and implantation. PMID:24687547

  4. Wear mechanism and tribological characteristics of porous NiTi shape memory alloy for bone scaffold.

    PubMed

    Wu, Shuilin; Liu, Xiangmei; Wu, Guosong; Yeung, Kelvin W K; Zheng, Dong; Chung, C Y; Xu, Z S; Chu, Paul K

    2013-09-01

    The abraded debris might cause osteocytic osteolysis on the interface between implants and bone tissues, thus inducing the subsequent mobilization of implants gradually and finally resulting in the failure of bone implants, which imposes restrictions on the applications of porous NiTi shape memory alloys (SMAs) scaffolds for bone tissue engineering. In this work, the effects of the annealing temperature, applied load, and porosity on the tribological behavior and wear resistance of three-dimensional porous NiTi SMA are investigated systematically. The porous structure and phase transformation during the exothermic process affect the tribological properties and wear mechanism significantly. In general, a larger porosity leads to better tribological resistance but sometimes, SMAs with small porosity possess better wear resistance than ones with higher porosity during the initial sliding stage. It can be ascribed to the better superelasticity of the former at the test temperature. The porous NiTi phase during the exothermic reaction also plays an important role in the wear resistance. Generally, porous NiTi has smaller friction coefficients under high loads due to stress-induced superelasticity. The wear mechanism is discussed based on plastic deformation and microcrack propagation. PMID:23401387

  5. Vascularization of hollow channel-modified porous silk scaffolds with endothelial cells for tissue regeneration.

    PubMed

    Zhang, Wenjie; Wray, Lindsay S; Rnjak-Kovacina, Jelena; Xu, Ling; Zou, Duohong; Wang, Shaoyi; Zhang, Maolin; Dong, Jiachen; Li, Guanglong; Kaplan, David L; Jiang, Xinquan

    2015-07-01

    Despite the promise for stem cell-based tissue engineering for regenerative therapy, slow and insufficient vascularization of large tissue constructs negatively impacts the survival and function of these transplanted cells. A combination of channeled porous silk scaffolds and prevascularization with endothelial cells was investigated to test the ability of this tissue engineering strategy to support rapid and extensive vascularization process. We report that hollow channels promote in vitro prevascularization by facilitating endothelial cell growth, VEGF secretion, and capillary-like tube formation. When implanted in vivo, the pre-established vascular networks in the hollow channel scaffolds anastomose with host vessels and exhibit accelerated vascular infiltration throughout the whole tissue construct, which provides timely and sufficient nutrients to ensure the survival of the transplanted stem cells. This tissue engineering strategy can promote the effective application of stem cell-based regeneration to improve future clinical applications. PMID:25934280

  6. Chondrogenic regeneration using bone marrow clots and a porous polycaprolactone-hydroxyapatite scaffold by three-dimensional printing.

    PubMed

    Yao, Qingqiang; Wei, Bo; Liu, Nancy; Li, Chenshuang; Guo, Yang; Shamie, Arya Nick; Chen, James; Tang, Cheng; Jin, Chengzhe; Xu, Yan; Bian, Xiuwu; Zhang, Xinli; Wang, Liming

    2015-04-01

    Scaffolds play an important role in directing three-dimensional (3D) cartilage regeneration. Our recent study reported the potential advantages of bone marrow clots (MC) in promoting extracellular matrix (ECM) scaffold chondrogenic regeneration. The aim of this study is to build a new scaffold for MC, with improved characteristics in mechanics, shaping, and biodegradability, compared to our previous study. To address this issue, this study prepared a 3D porous polycaprolactone (PCL)-hydroxyapatite (HA) scaffold combined with MC (Group A), while the control group (Group B) utilized a bone marrow stem cell seeded PCL-HA scaffold. The results of in vitro cultures and in vivo implantation demonstrated that although an initial obstruction of nutrient exchange caused by large amounts of fibrin and erythrocytes led to a decrease in the ratio of live cells in Group A, these scaffolds also showed significant improvements in cell adhesion, proliferation, and chondrogenic differentiation with porous recanalization in the later culture, compared to Group B. After 4 weeks of in vivo implantation, Group A scaffolds have a superior performance in DNA content, Sox9 and RunX2 expression, cartilage lacuna-like cell and ECM accumulation, when compared to Group B. Furthermore, Group A scaffold size and mechanics were stable during in vitro and in vivo experiments, unlike the scaffolds in our previous study. Our results suggest that the combination with MC proved to be a highly efficient, reliable, and simple new method that improves the biological performance of 3D PCL-HA scaffold. The MC-PCL-HA scaffold is a candidate for future cartilage regeneration studies. PMID:25530453

  7. Improved dimensional stability with bioactive glass fibre skeleton in poly(lactide-co-glycolide) porous scaffolds for tissue engineering.

    PubMed

    Haaparanta, Anne-Marie; Uppstu, Peter; Hannula, Markus; Ellä, Ville; Rosling, Ari; Kellomäki, Minna

    2015-11-01

    Bone tissue engineering requires highly porous three-dimensional (3D) scaffolds with preferable osteoconductive properties, controlled degradation, and good dimensional stability. In this study, highly porous 3D poly(d,l-lactide-co-glycolide) (PLGA) - bioactive glass (BG) composites (PLGA/BG) were manufactured by combining highly porous 3D fibrous BG mesh skeleton with porous PLGA in a freeze-drying process. The 3D structure of the scaffolds was investigated as well as in vitro hydrolytic degradation for 10weeks. The effect of BG on the dimensional stability, scaffold composition, pore structure, and degradation behaviour of the scaffolds was evaluated. The composites showed superior pore structure as the BG fibres inhibited shrinkage of the scaffolds. The BG was also shown to buffer the acidic degradation products of PLGA. These results demonstrate the potential of these PLGA/BG composites for bone tissue engineering, but the ability of this kind of PLGA/BG composites to promote bone regeneration will be studied in forthcoming in vivo studies. PMID:26249615

  8. Subcritical CO2 Sintering of Microspheres of Different Polymeric Materials to Fabricate Scaffolds for Tissue Engineering

    PubMed Central

    Bhamidipati, Manjari; Sridharan, BanuPriya; Scurto, Aaron M; Detamore, Michael S.

    2013-01-01

    The aim of this study was to use CO2 at sub-critical pressures as a tool to sinter 3D, macroporous, microsphere-based scaffolds for bone and cartilage Tissue Engineering Porous scaffolds composed of ~200 µm microspheres of either poly(lactic-co-glycolic acid) (PLGA) or polycaprolactone (PCL) were prepared using dense phase CO2 sintering, which were seeded with rat bone marrow mesenchymal stromal cells (rBMSCs), and exposed to either osteogenic (PLGA, PCL) or chondrogenic (PLGA) conditions for 6 weeks. Under osteogenic conditions, the PLGA constructs produced over an order of magnitude more calcium than the PCL constructs, whereas the PCL constructs had far superior mechanical and structural integrity (125 times stiffer than PLGA constructs) at week 6, along with twice the cell content of the PLGA constructs. Chondrogenic cell performance was limited in PLGA constructs, perhaps as a result of the polymer degradation rate being too high. The current study represents the first long-term culture of CO2-sintered microsphere-based scaffolds, and has established important thermodynamic differences in sintering between the selected formulations of PLGA and PCL, with the former requiring adjustment of pressure only, and the latter requiring the adjustment of both pressure and temperature. Based on more straightforward sintering conditions and more favorable cell performance, PLGA may be the material of choice for microspheres in a CO2 sintering application, although a different PLGA formulation with the encapsulation of growth factors, extracellular matrix-derived nanoparticles, and/or buffers in the microspheres may be advantageous for achieving a more superior cell performance than observed here. PMID:24094202

  9. A comparison study of different physical treatments on cartilage matrix derived porous scaffolds for tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Moradi, Ali; Pramanik, Sumit; Ataollahi, Forough; Khalil, Alizan Abdul; Kamarul, Tunku; Pingguan-Murphy, Belinda

    2014-12-01

    Native cartilage matrix derived (CMD) scaffolds from various animal and human sources have drawn attention in cartilage tissue engineering due to the demonstrable presence of bioactive components. Different chemical and physical treatments have been employed to enhance the micro-architecture of CMD scaffolds. In this study we have assessed the typical effects of physical cross-linking methods, namely ultraviolet (UV) light, dehydrothermal (DHT) treatment, and combinations of them on bovine articular CMD porous scaffolds with three different matrix concentrations (5%, 15% and 30%) to assess the relative strengths of each treatment. Our findings suggest that UV and UV-DHT treatments on 15% CMD scaffolds can yield architecturally optimal scaffolds for cartilage tissue engineering.

  10. Stress-strain analysis of porous scaffolds made from titanium alloys synthesized via SLS method

    NASA Astrophysics Data System (ADS)

    Shishkovsky, I.

    2009-09-01

    A layer-by-layer selective laser sintering (SLS) technology seems to be greatly promising for solving the plastic surgery problems, particularly those pertaining to the facial reconstruction. Made from titanium-based alloys (titanium or nitinol, i.e. NiTi-intermetallic phase), the porous scaffolds for cranioplasty are an efficient tool for rectifying the face defects and for the dental orthopedic surgery. The progress in the oral surgery and teeth implantation is caused by the problem of an osteointegration on the one hand, and by achievements of the implant synthesis techniques, on the other hand. An important problem thereby is a profound study of the stress-strain behavior of porous implants under the masticatory load or pressure. In the present study the ways for the optimization of the porous implant structural and strength properties as the function of the laser synthesis parameters are described. The finite element approach (ANSYS) was used here for a complex dowel description and numerical simulations. In order to evaluate the processes in the porous implant under the external loading, a CAD 3D model was built for different internal and external configurations of the implant and/or initial shape of powdered particles. The stress-strain dependences were calculated that displayed the irregularity of the stress distribution by the implant volume in the bone tissue. Most of the values are concentrated in places of object contact.

  11. Biodegradable and bioactive porous scaffold structures prepared using fused deposition modeling.

    PubMed

    Korpela, Jyrki; Kokkari, Anne; Korhonen, Harri; Malin, Minna; Närhi, Timo; Seppälä, Jukka

    2013-05-01

    Three-dimensional printing (3DP) refers to a group of additive manufacturing techniques that can be utilized in tissue engineering applications. Fused deposition modeling (FDM) is a 3DP method capable of using common thermoplastic polymers. However, the scope of materials applicable for FDM has not been fully recognized. The purpose of this study was to examine the creation of biodegradable porous scaffold structures using different materials in FDM and to determine the compressive properties and the fibroblast cell response of the structures. To the best of our knowledge, the printability of a poly(?-caprolactone)/bioactive glass (PCL/BAG) composite and L-lactide/?-caprolactone 75/25 mol % copolymer (PLC) was demonstrated for the first time. Scanning electron microscope (SEM) images showed BAG particles at the surface of the printed PCL/BAG scaffolds. Compressive testing showed the possibility of altering the compressive stiffness of a scaffold without changing the compressive modulus. Compressive properties were significantly dependent on porosity level and structural geometry. Fibroblast proliferation was significantly higher in polylactide than in PCL or PCL/BAG composite. Optical microscope images and SEM images showed the viability of the cells, which demonstrated the biocompatibility of the structures. PMID:23281260

  12. Influence of Parathyroid Hormone-Loaded PLGA Nanoparticles in Porous Scaffolds for Bone Regeneration

    PubMed Central

    Gentile, Piergiorgio; Nandagiri, Vijay Kumar; Pabari, Ritesh; Daly, Jacqueline; Tonda-Turo, Chiara; Ciardelli, Gianluca; Ramtoola, Zebunnissa

    2015-01-01

    Biodegradable poly(lactide-co-glycolide) (PLGA) nanoparticles, containing human parathyroid hormone (PTH (1–34)), prepared by a modified double emulsion-solvent diffusion-evaporation method, were incorporated in porous freeze-dried chitosan-gelatin (CH-G) scaffolds. The PTH-loaded nanoparticles (NPTH) were characterised in terms of morphology, size, protein loading, release kinetics and in vitro assessment of biological activity of released PTH and cytocompatibility studies against clonal human osteoblast (hFOB) cells. Structural integrity of incorporated and released PTH from nanoparticles was found to be intact by using Tris-tricine SDS-PAGE. In vitro PTH release kinetics from PLGA nanoparticles were characterised by a burst release followed by a slow release phase for 3–4 weeks. The released PTH was biologically active as evidenced by the stimulated release of cyclic AMP from hFOB cells as well as increased mineralisation studies. Both in vitro and cell studies demonstrated that the PTH bioactivity was maintained during the fabrication of PLGA nanoparticles and upon release. Finally, a content of 33.3% w/w NPTHs was incorporated in CH-G scaffolds, showing an intermittent release during the first 10 days and, followed by a controlled release over 28 days of observation time. The increased expression of Alkaline Phosphatase levels on hFOB cells further confirmed the activity of intermittently released PTH from scaffolds. PMID:26343649

  13. Bone regeneration in strong porous bioactive glass (13–93) scaffolds with an oriented microstructure implanted in rat calvarial defects

    PubMed Central

    Liu, Xin; Rahaman, Mohamed N.; Fu, Qiang

    2012-01-01

    There is a need for synthetic bone graft substitutes to repair large bone defects resulting from trauma, malignancy, and congenital diseases. Bioactive glass has attractive properties as a scaffold material but factors that influence its ability to regenerate bone in vivo are not well understood. In the present work, the ability of strong porous scaffolds of 13–93 bioactive glass with an oriented microstructure to regenerate bone was evaluated in vivo using a rat calvarial defect model. Scaffolds with an oriented microstructure of columnar pores (porosity = 50%; pore diameter = 50–150 µm) showed mostly osteoconductive bone regeneration, and new bone formation, normalized to the available pore area (volume) of the scaffolds, increased from 37% at 12 weeks to 55% at 24 weeks. Scaffolds of the same glass with a trabecular microstructure (porosity = 80%; pore width = 100–500 µm), used as the positive control, showed bone regeneration in the pores of 25% and 46% at 12 and 24 weeks, respectively. The brittle mechanical response of the as-fabricated scaffolds changed markedly to an elasto-plastic response in vivo at both implantation times. These results indicate that both groups of 13–93 bioactive glass scaffolds could potentially be used to repair large bone defects, but scaffolds with the oriented microstructure could also be considered for the repair of loaded bone. PMID:22922251

  14. Porous diopside (CaMgSi(2)O(6)) scaffold: A promising bioactive material for bone tissue engineering.

    PubMed

    Wu, Chengtie; Ramaswamy, Yogambha; Zreiqat, Hala

    2010-06-01

    Diopside (CaMgSi(2)O(6)) powders and dense ceramics have been shown to be bioactive biomaterials for bone repair. The aim of this study is to prepare bioactive diopside scaffolds and examine their physicochemical and biological properties. X-ray diffraction, scanning electron microscopy (SEM), micro-computerized tomography and energy-dispersive spectrometry were used to analyse the composition, microstructure, pore size and interconnectivity of the diopside scaffolds. The mechanical strength and stability as well as the degradation of the scaffolds were investigated by testing the compressive strength, modulus and silicon ions released, respectively. Results showed that highly porous diopside scaffolds with varying porosity and high interconnectivity of 97% were successfully prepared with improved compressive strength and mechanical stability, compared to the bioglass and CaSiO(3) scaffolds. The bioactivity of the diopside scaffolds was assessed using apatite-forming ability in simulated body fluids (SBF) and by their support for human osteoblastic-like cell (HOB) attachment, proliferation and differentiation using SEM, and MTS and alkaline phosphatase activity assays, respectively. Results showed that diopside scaffolds possessed apatite-forming ability in SBF and supported HOB attachment proliferation and differentiation. Bioactive diopside scaffolds were prepared with excellent pore/structure art, and improved mechanical strength and mechanical stability, suggesting their possible applications for bone tissue engineering regeneration. PMID:20018260

  15. Porous, Biphasic CaCO3-Calcium Phosphate Biomedical Cement Scaffolds from Calcite (CaCO3) Powder

    E-print Network

    Tas, A. Cuneyt

    Porous, Biphasic CaCO3-Calcium Phosphate Biomedical Cement Scaffolds from Calcite (CaCO3) Powder A. Cuneyt Tas* Department of Biomedical Engineering, Yeditepe University, Istanbul 34755, Turkey Calcite (CaH 3.2 by adding NaOH, to form biphasic, micro-, and macroporous calcite-apatitic calcium phosphate (Ap

  16. 3D Porous Chitosan-Alginate Scaffolds: New Matrix for Studying Prostate Cancer Cell-Lymphocyte Interactions In Vitro

    PubMed Central

    Florczyk, Stephen J.; Liu, Gang; Kievit, Forrest M.; Lewis, Allison M.; Wu, Jennifer D.

    2013-01-01

    The treatment of castration-resistant prostate cancer (CRPC) remains palliative. Immunotherapy offers a potentially effective therapy for CRPC; however, its advancement into the clinic has been slow, in part because of the lack of representative in vitro tumor models that resemble the in vivo tumor microenvironment for studying interactions of CRPC cells with immune cells and other potential therapeutics. This study evaluates the use of 3D porous chitosan-alginate (CA) scaffolds for culturing human prostate cancer (PCa) cells and studying tumor cell interaction with human peripheral blood lymphocytes (PBLs) ex vivo. CA scaffolds and Matrigel matrix samples supported in vitro tumor spheroid formation over 15 days of culture, and CA scaffolds supported live cell fluorescence imaging with confocal microscopy using stably transfected PCa cells for 55 days. PCa cells grown in Matrigel matrix and CA scaffolds for 15 days were co-cultured with PBLs for 2 and 6 days in vitro and evaluated with scanning electron microscopy (SEM), immunohistochemistry (IHC), and flow cytometry. Both the Matrigel matrix and CA scaffolds supported interaction of PBLs with PCa tumors, with CA scaffolds providing a more robust platform for subsequent analyses. This study demonstrates the use of 3D natural polymer scaffolds as a tissue culture model for supporting long-term analysis of interaction of prostate cancer tumor cells with immune cells, providing an in vitro platform for rapid immunotherapy development. PMID:23184794

  17. Porous collagen-hydroxyapatite scaffolds with mesenchymal stem cells for bone regeneration.

    PubMed

    Ning, Li; Malmström, Hans; Ren, Yan-Fang

    2015-02-01

    Current bone grafting materials have significant limitations for repairing maxillofacial and dentoalveolar bone deficiencies. An ideal bone tissue-engineering construct is still lacking. The purpose of the present study was first to synthesize and develop a collagen-hydroxyapatite (Col-HA) composite through controlled in situ mineralization on type I collagen fibrils with nanometer-sized apatite crystals, and then evaluate their biologic properties by culturing with mouse and human mesenchymal stem cells (MSCs). We synthesized Col-HA scaffolds with different Col:HA ratios. Mouse C3H10T1/2 MSCs and human periodontal ligament stem cells (hPDSCs) were cultured with scaffolds for cell proliferation and biocompatibility assays. We found that the porous Col-HA composites have good biocompatibility and biomimetic properties. The Col-HA composites with ratios 80:20 and 50:50 composites supported the attachments and proliferations of mouse MSCs and hPDSCs. These findings indicate that Col-HA composite complexes have strong potentials for bone tissue regeneration. PMID:23574526

  18. Nanostructured Porous Silicon: The Winding Road from Photonics to Cell Scaffolds – A Review

    PubMed Central

    Hernández-Montelongo, Jacobo; Muñoz-Noval, Alvaro; García-Ruíz, Josefa Predestinación; Torres-Costa, Vicente; Martín-Palma, Raul J.; Manso-Silván, Miguel

    2015-01-01

    For over 20?years, nanostructured porous silicon (nanoPS) has found a vast number of applications in the broad fields of photonics and optoelectronics, triggered by the discovery of its photoluminescent behavior in 1990. Besides, its biocompatibility, biodegradability, and bioresorbability make porous silicon (PSi) an appealing biomaterial. These properties are largely a consequence of its particular susceptibility to oxidation, leading to the formation of silicon oxide, which is readily dissolved by body fluids. This paper reviews the evolution of the applications of PSi and nanoPS from photonics through biophotonics, to their use as cell scaffolds, whether as an implantable substitute biomaterial, mainly for bony and ophthalmological tissues, or as an in vitro cell conditioning support, especially for pluripotent cells. For any of these applications, PSi/nanoPS can be used directly after synthesis from Si wafers, upon appropriate surface modification processes, or as a composite biomaterial. Unedited studies of fluorescently active PSi structures for cell culture are brought to evidence the margin for new developments. PMID:26029688

  19. Design and application of chitosan/biphasic calcium phosphate porous scaffolds for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Sendemir-Urkmez, Aylin

    For the restoration of maxillofacial bone tissue, design of novel tissue engineering scaffolds capable of inducing bone remodeling through the delivery of mesenchymal stem cells (MSCs) and an angiogenic growth factor, directly at the site of the defect was investigated in order to replace autogenous cancellous bone grafts with synthetic materials. Porous, three dimensional scaffolds were fabricated by a freeze drying method. In culture media, biphasic calcium phosphate particles within chitosan produced a surface reprecipitate of a composition similar to natural apatite that led to a uniform distribution of cells and mineralized ECM through chemotaxis. Further, the reprecipitation regulated the differentiation pathway and phenotype commitment of stem cells by altering the initial cell attachment morphology and actin cytoskeleton organization. In order to induce neovascularization after implantation, constructs were designed to be loaded with gelatin microspheres that delivered basic fibroblast growth factor (bFGF), a potent angiogenic factor. In vitro proliferation tests performed on fibroblastic cells showed no detectible loss of bFGF activity when delivered through enzymatic degradation of gelatin. Laser scanning confocal microscopy was used to demonstrate that gelatin microspheres can be injected evenly into cell-scaffold constructs owing to the spongy characteristics of the scaffold. To examine the binding interactions of bFGF with surface bound gelatin, a label free biosensor system, Biomolecular INteraction Detection sensor (BIND) was used. Results confirm that the principal interaction that takes place between bFGF and gelatin is electrostatic. Cell loaded tissue engineered constructs were produced in vitro at clinically relevant sizes and implanted with and without bFGF into a porcine mandibular defect model. Tissue engineered constructs facilitated the healing of mandibular defects only if combined with delivery of bFGF via gelatin microspheres. bFGF release from the constructs improved neovascularization in the defect area and subsequently enhanced new bone formation. Although the rate and extent of bone formation was similar in bFGF group to those in empty defects for the period of the study, existence of woven bone in bFGF group suggests that bone formation is continuing while the lamellar structure in empty defects indicates that bone formation in that group was finalized.

  20. Osteogenic Differentiation of Human Mesenchymal Stem Cells in 3-D Zr-Si Organic-Inorganic Scaffolds Produced by Two-Photon Polymerization Technique

    PubMed Central

    Koroleva, Anastasia; Deiwick, Andrea; Nguyen, Alexander; Schlie-Wolter, Sabrina; Narayan, Roger; Timashev, Peter; Popov, Vladimir; Bagratashvili, Viktor; Chichkov, Boris

    2015-01-01

    Two-photon polymerization (2PP) is applied for the fabrication of 3-D Zr-Si scaffolds for bone tissue engineering. Zr-Si scaffolds with 150, 200, and 250 ?m pore sizes are seeded with human bone marrow stem cells (hBMSCs) and human adipose tissue derived stem cells (hASCs) and cultured in osteoinductive and control media for three weeks. Osteogenic differentiation of hASCs and hBMSCs and formation of bone matrix is comparatively analyzed via alkaline phosphatase activity (ALP), calcium quantification, osteocalcin staining and scanning electron microscopy (SEM). It is observed that the 150 ?m pore size Zr-Si scaffolds support the strongest matrix mineralization, as confirmed by calcium deposition. Analysis of ALP activity, osteocalcin staining and SEM observations of matrix mineralization reveal that mesenchymal stem cells cultured on 3-D scaffolds without osteogenic stimulation spontaneously differentiate towards osteogenic lineage. Nanoindentation measurements show that aging of the 2PP-produced Zr-Si scaffolds in aqueous or alcohol media results in an increase in the scaffold Young’s modulus and hardness. Moreover, accelerated formation of bone matrix by hASCs is noted, when cultured on the scaffolds with lower Young’s moduli and hardness values (non aged scaffolds) compared to the cells cultured on scaffolds with higher Young’s modulus and hardness values (aged scaffolds). Presented results support the potential application of Zr-Si scaffolds for autologous bone tissue engineering. PMID:25706270

  1. Comparison of different fabrication techniques used for processing 3-dimensional, porous, biodegradable scaffolds from modified starch for bone tissue engineering.

    PubMed

    Kunjachan, V; Subramanian, A; Hanna, M; Guan, J J

    2004-01-01

    3 dimensional, porous, biodegradable scaffolds were fabricated using modified starch of varying degree of substitution (DS) by extrusion processing. Freeze drying/lyophilization was also employed to fabricate scaffolds from modified starch. The research efforts have been focused on the comparison of the above-mentioned techniques by comparing the properties of the fabricated scaffolds in the paradigm of bone tissue engineering. The physicomechanical properties like porosity, compressive strength and modulus, pore size and microstructure were tested and analyzed by liquid replacement, mechanical testing and scanning electron microscopy respectively. The biodegradability of scaffolds was evaluated by soaking the samples in aqueous medium and Hank's balanced salt solution at 37-degree invitro. The cytotoxicity studies on these scaffolds were also conducted. The scaffolds have a 3D structure consisting of interconnected pores with good porosity, pore size, adequate compressive strength and modulus and exhibit good biodegradability as well as biocompatibility. After further optimization in the processing conditions and parameters they could be made useful for bone tissue engineering. PMID:15133947

  2. Influence of the laser assisted fabricated 3D porous scaffolds from bioceramoplasts of micron and nano sizes on culture of MMSC

    NASA Astrophysics Data System (ADS)

    Shishkovsky, I.; Volchkov, S.

    2013-11-01

    The objective of the investigation was to test the biocompatibility of 3D porous biopolymer matrices (tissue-cellular scaffolds), made of biocompatible and bioresorbable polymers (polycarbonate, polyetheretherketone /PEEK/, polycaprolactone), including the materials with biocompatible oxide ceramics additive (TiO2, Al2O3, ZrO2 and hydroxyapatite) of micron and nano sizes, for tissue-engineering purposes. The porous samples were prepared via a layer-by-layer SLS method. The surface microstructures and their roughness were analyzed by the optical microscopy equipped with the cell analysis software. The cellular morphology, proliferative activity and adhesion of the polymeric and ceramopolymeric matrices were the subjects for comparison. The study showed that all the tested materials posessed biocompatible properties. The experimentally estimated cell duplication speed per day turned out to be maximal for polycarbonate (0.279 duplications per day) and for PEEK + Al2O3 = 3:1 group (0.30 dupl/day) against 0.387 dupl/day for the reference sample and 0.270 dupl/day for the group of cells placed close to the pure titanium samples.

  3. Synthesis of composite gelatin-hyaluronic acid-alginate porous scaffold and evaluation for in vitro stem cell growth and in vivo tissue integration.

    PubMed

    Singh, Deepti; Tripathi, Anuj; Zo, Sunmi; Singh, Dolly; Han, Sung Soo

    2014-04-01

    Engineering three-dimensional (3-D) porous scaffolds with precise bio-functional properties is one of the most important issues in tissue engineering. In the present study, a three-dimensional gelatin-hyaluronic acid-alginate (GHA) polymeric composite was synthesized by freeze-drying, which was followed by ionic crosslinking using CaCl2, and evaluated for its suitability in bone tissue engineering applications. The obtained matrix showed high porosity (85%), an interconnected pore morphology and a rapid swelling behavior. The rheological analysis of GHA showed a viscoelastic characteristic, which suggested a high load bearing capacity without fractural deformation. The influence of the GHA matrix on cell growth and on modulating the differentiation ability of mesenchymal stem cells was evaluated by different biochemical and immunostaining assays. The monitoring of cells over a period of four weeks showed increased cellular proliferation and osteogenic differentiation without external growth factors, compared with control (supplemented with osteogenic differentiation medium). The in vivo matrix implantation showed higher matrix-tissue integration and cell infiltration as the duration of the implant increased. These results suggest that a porous GHA matrix with suitable mechanical integrity and tissue compatibility is a promising substrate for the osteogenic differentiation of stem cells for bone tissue engineering applications. PMID:24572494

  4. Nano SiO2 and MgO Improve the Properties of Porous ?-TCP Scaffolds via Advanced Manufacturing Technology

    PubMed Central

    Gao, Chengde; Wei, Pingpin; Feng, Pei; Xiao, Tao; Shuai, Cijun; Peng, Shuping

    2015-01-01

    Nano SiO2 and MgO particles were incorporated into ?-tricalcium phosphate (?-TCP) scaffolds to improve the mechanical and biological properties. The porous cylindrical ?-TCP scaffolds doped with 0.5 wt % SiO2, 1.0 wt % MgO, 0.5 wt % SiO2 + 1.0 wt % MgO were fabricated via selective laser sintering respectively and undoped ?-TCP scaffold was also prepared as control. The phase composition and mechanical strength of the scaffolds were evaluated. X-ray diffraction analysis indicated that the phase transformation from ?-TCP to ?-TCP was inhibited after the addition of MgO. The compressive strength of scaffold was improved from 3.12 ± 0.36 MPa (?-TCP) to 5.74 ± 0.62 MPa (?-TCP/SiO2), 9.02 ± 0.55 MPa (?-TCP/MgO) and 10.43 ± 0.28 MPa (?-TCP/SiO2/MgO), respectively. The weight loss and apatite-forming ability of the scaffolds were evaluated by soaking them in simulated body fluid. The results demonstrated that both SiO2 and MgO dopings slowed down the degradation rate and improved the bioactivity of ?-TCP scaffolds. In vitro cell culture studies indicated that SiO2 and MgO dopings facilitated cell attachment and proliferation. Combined addition of SiO2 and MgO were found optimal in enhancing both the mechanical and biological properties of ?-TCP scaffold. PMID:25815597

  5. Image processing and fractal box counting: user-assisted method for multi-scale porous scaffold characterization.

    PubMed

    Guarino, Vincenzo; Guaccio, Angela; Netti, Paolo A; Ambrosio, Luigi

    2010-12-01

    Image analysis has gained new effort in the scientific community due to the chance of investigating morphological properties of three dimensional structures starting from their bi-dimensional gray-scale representation. Such ability makes it particularly interesting for tissue engineering (TE) purposes. Indeed, the capability of obtaining and interpreting images of tissue scaffolds, extracting morphological and structural information, is essential to the characterization and design of engineered porous systems. In this work, the traditional image analysis approach has been coupled with a probabilistic based percolation method to outline a general procedure for analysing tissue scaffold SEM micrographs. To this aim a case study constituted by PCL multi-scaled porous scaffolds was adopted. Moreover, the resulting data were compared with the outputs of conventionally used techniques, such as mercury intrusion porosimetry. Results indicate that image processing methods well fit the porosity features of PCL scaffolds, overcoming the limits of the more invasive porosimetry techniques. Also the cut off resolution of such IP methods was discussed. Moreover, the fractal dimension of percolating clusters, within the pore populations, was addressed as a good indication of the interconnection degree of PCL bi-modal scaffolds. Such findings represent (i) the bases for a novel approach complementary to the conventional experimental procedure used for the morphological analysis of TE scaffolds, in particular offering a valid method for the analysis of soft materials (i.e., gels); also (ii) providing a new perspective for further studies integrating to the structural and morphological data, fluid-dynamics and transport properties modelling. PMID:20922560

  6. An ultra-sensitive microfluidic immunoassay using living radical polymerization and porous polymer monoliths.

    SciTech Connect

    Abhyankar, Vinay V.; Singh, Anup K.; Hatch, Anson V.

    2010-07-01

    We present a platform that combines patterned photopolymerized polymer monoliths with living radical polymerization (LRP) to develop a low cost microfluidic based immunoassay capable of sensitive (low to sub pM) and rapid (<30 minute) detection of protein in 100 {micro}L sample. The introduction of LRP functionality to the porous monolith allows one step grafting of functionalized affinity probes from the monolith surface while the composition of the hydrophilic graft chain reduces non-specific interactions and helps to significantly improve the limit of detection.

  7. Improvement of Distribution and Osteogenic Differentiation of Human Mesenchymal Stem Cells by Hyaluronic Acid and ?-Tricalcium Phosphate-Coated Polymeric Scaffold In Vitro

    PubMed Central

    Chen, Muwan; Le, Dang Q.S.; Kjems, Jørgen; Bünger, Cody; Lysdahl, Helle

    2015-01-01

    Abstract Bone tissue engineering requires a well-designed scaffold that can be biodegradable, biocompatible, and support the stem cells to osteogenic differentiation. Porous polycaprolactone (PCL) scaffold prepared by fused deposition modeling is an attractive biomaterial that has been used in clinic. However, PCL scaffolds lack biological function and osteoinductivity. In this study, we functionalized the PCL scaffolds by embedding them with a matrix of hyaluronic acid/?-tricalcium phosphate (HA/TCP). Human mesenchymal stem cells (MSCs) were cultured on scaffolds with and without coating to investigate proliferation and osteogenic differentiation. The DNA amount was significantly higher in the HA/TCP-coated scaffold on day 21. At the gene expression level, HA/TCP coating significantly increased the expression of ALP and COLI on day 4. These data correlated with the ALP activity peaking on day 7 in the HA/TCP-coated scaffold. Scanning electron microscope and histological analysis revealed that the cell matrix and calcium deposition were distributed more uniformly in the coated scaffolds compared to scaffolds without coating. In conclusion, the HA/TCP coating improved cellular proliferation, osteogenic differentiation, and uniform distribution of the cellular matrix in vitro. The HA/TCP-PCL scaffold holds great promise to accommodate human bone marrow-derived MSCs for bone reconstruction purposes, which warrants future in vivo studies. PMID:26487981

  8. Osteogenic differentiation of umbilical cord and adipose derived stem cells onto highly porous 45S5 Bioglass®-based scaffolds.

    PubMed

    Detsch, Rainer; Alles, Sonja; Hum, Jasmin; Westenberger, Peter; Sieker, Frank; Heusinger, Dominik; Kasper, Cornelia; Boccaccini, Aldo R

    2015-03-01

    In the context of bone tissue engineering (BTE), combinations of bioactive scaffolds with living cells are investigated to optimally yield functional bone tissue for implantation purposes. Bioactive glasses are a class of highly bioactive, inorganic materials with broad application potential in BTE strategies. The aim of this study was to evaluate bioactive glass (45S5 Bioglass(®)) samples of composition: 45 SiO2, 24.5 CaO, 24.5 Na2O, and 6 P2O5 (in wt%) as scaffold materials for mesenchymal stem cells (MSC). Pore architecture of the scaffolds as well as cell behavior in the three-dimensional environment was evaluated by several methods. Investigations concerned the osteogenic cell attachment, growth and differentiation of adipose tissue derived MSC (adMSC) compared with MSC from human full term umbilical cord tissues (ucMSC) on porous Bioglass(®)-based scaffolds over a cultivation period of 5 weeks. Differences in lineage-specific osteogenic differentiation of adMSC and ucMSC on Bioglass(®) samples were demonstrated. The investigation led to positive results in terms of cell attachment, proliferation, and differentiation of MSC onto Bioglass(®)-based scaffolds confirming the relevance of these matrices for BTE applications. PMID:24853477

  9. Preparation of porous 45S5 Bioglass-derived glass-ceramic scaffolds by using rice husk as a porogen additive.

    PubMed

    Wu, Shih-Ching; Hsu, Hsueh-Chuan; Hsiao, Sheng-Hung; Ho, Wen-Fu

    2009-06-01

    Bioactive glass is currently regarded as the most biocompatible material in the bone regeneration field because of its bioactivity, osteoconductivity and even osteoinductivity. In the present work porous glass-ceramic scaffolds, which were prepared from the 45S5 Bioglass by foaming with rice husks and sintering at 1050 degrees C for 1 h, have been developed. The produced scaffolds were characterized for their morphology, properties and bioactivity. Micrographs taken using a scanning electron microscope (SEM) were used for analysis of macropores, mesopores and micropores, respectively. The bioactivity of the porous glass-ceramic scaffolds was investigated using simulated body fluid (SBF) and characterized by SEM, energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). A great potential scaffold that provides sufficient mechanical support temporarily while maintaining bioactivity, and that can biodegrade at later stages is achievable with the developed 45S5 Bioglass-derived scaffolds. PMID:19160020

  10. Polymeric vs hydroxyapatite-based scaffolds on dental pulp stem cell proliferation and differentiation

    PubMed Central

    Khojasteh, Arash; Motamedian, Saeed Reza; Rad, Maryam Rezai; Shahriari, Mehrnoosh Hasan; Nadjmi, Nasser

    2015-01-01

    AIM: To evaluate adhesion, proliferation and differentiation of human dental pulp stem cells (hDPSCs) on four commercially available scaffold biomaterials. METHODS: hDPSCs were isolated from human dental pulp tissues of extracted wisdom teeth and established in stem cell growth medium. hDPSCs at passage 3-5 were seeded on four commercially available scaffold biomaterials, SureOss (Allograft), Cerabone (Xenograft), PLLA (Synthetic), and OSTEON II Collagen (Composite), for 7 and 14 d in osteogenic medium. Cell adhesion and morphology to the scaffolds were evaluated by scanning electron microscopy (SEM). Cell proliferation and differentiation into osteogenic lineage were evaluated using DNA counting and alkaline phosphatase (ALP) activity assay, respectively. RESULTS: All scaffold biomaterials except SureOss (Allograft) supported hDPSC adhesion, proliferation and differentiation. hDPSCs seeded on PLLA (Synthetic) scaffold showed the highest cell proliferation and attachment as indicated with both SEM and DNA counting assay. Evaluating the osteogenic differentiation capability of hDPSCs on different scaffold biomaterials with ALP activity assay showed high level of ALP activity on cells cultured on PLLA (Synthetic) and OSTEON II Collagen (Composite) scaffolds. SEM micrographs also showed that in the presence of Cerabone (Xenograft) and OSTEON II Collagen (Composite) scaffolds, the hDPSCs demonstrated the fibroblastic phenotype with several cytoplasmic extension, while the cells on PLLA scaffold showed the osteoblastic-like morphology, round-like shape. CONCLUSION: PLLA scaffold supports adhesion, proliferation and osteogenic differentiation of hDPSCs. Hence, it may be useful in combination with hDPSCs for cell-based reconstructive therapy. PMID:26640621

  11. Stabilization of porous chitosan improves the performance of its association with platelet-rich plasma as a composite scaffold.

    PubMed

    Shimojo, A A M; Perez, A G M; Galdames, S E M; Brissac, I C S; Santana, M H A

    2016-03-01

    This study offers innovative perspectives for optimizing of scaffolds based on correlation structure-function aimed the regenerative medicine. Thus, we evaluated in vitro performance of stabilized porous chitosan (SPCHTs) associated with activated platelet-rich plasma (aP-PRP) as a composite scaffold for the proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells (h-AdMSCs). The porous structure of chitosan (PCHT) was prepared similarly to solid sponges by controlled freezing (-20°C) and lyophilization of a 3% (w/v) chitosan solution. Stabilization was performed by treating the PCHT with sodium hydroxide (TNaOH), an ethanol series (TEtOH) or by crosslinking with tripolyphosphate (CTPP). The aP-PRP was obtained from the controlled centrifugation of whole blood and activated with autologous serum and calcium. Imaging of the structures showed fibrin networks inside and on the surface of SPCHTs as a consequence of electrostatic interactions. SPCHTs were non-cytotoxic, and the porosity, pore size and Young's modulus were approximately 96%, 145?m and 1.5MPa for TNaOH and TEtOH and 94%, 110?m and 1.8MPa for CTPP, respectively. Stabilization maintained the integrity of the SPCHTs for at least 10days of cultivation. SPCHTs showed controlled release of the growth factors TGF-?1 and PDGF-AB. Although generating different patterns, all of the stabilization treatments improved the proliferation of seeded h-AdMSCs on the composite scaffold compared to aP-PRP alone, and differentiation of the composite scaffold treated with TEtOH was significantly higher than for non-stabilized PCHT. We conclude that the composite scaffolds improved the in vitro performance of PRP and have potential in regenerative medicine. PMID:26706561

  12. Preparation and characterization of highly porous, biodegradable polyurethane scaffolds for soft tissue applications

    PubMed Central

    Guan, Jianjun; Fujimoto, Kazuro L.; Sacks, Michael S.; Wagner, William R.

    2010-01-01

    In the engineering of soft tissues, scaffolds with high elastance and strength coupled with controllable biodegradable properties are necessary. To fulfill such design criteria we have previously synthesized two kinds of biodegradable polyurethaneureas, namely poly(ester urethane)urea (PEUU) and poly(ether ester urethane)urea (PEEUU) from polycaprolactone, polycaprolactone-b-polyethylene glycol-b-polycaprolactone, 1,4-diisocyanatobutane and putrescine. PEUU and PEEUU were further fabricated into scaffolds by thermally induced phase separation using dimethyl sulfoxide (DMSO) as a solvent. The effect of polymer solution concentration, quenching temperature and polymer type on pore morphology and porosity was investigated. Scaffolds were obtained with open and interconnected pores having sizes ranging from several ?m to more than 150 ?m and porosities of 80–97%. By changing the polymer solution concentration or quenching temperature, scaffolds with random or oriented tubular pores could be obtained. The PEUU scaffolds were flexible with breaking strains of 214% and higher, and tensile strengths of approximately 1.0 MPa, whereas the PEEUU scaffolds generally had lower strengths and breaking strains. Scaffold degradation in aqueous buffer was related to the porosity and polymer hydrophilicity. Smooth muscle cells were filtration seeded in the scaffolds and it was shown that both scaffolds supported cell adhesion and growth, with smooth muscle cells growing more extensively in the PEEUU scaffold. These biodegradable and flexible scaffolds demonstrate potential for future application as cell scaffolds in cardiovascular tissue engineering or other soft tissue applications. PMID:15626443

  13. Pore size reduction in directional crystallization processing of porous polymeric membranes.

    PubMed

    Kim, Byoung Soo; Lee, Jonghwi

    2013-03-01

    Although various prep technologies of porous polymeric materials have evolved, the versatile control of pore morphology still remains as the most demanding subject. Herein, we applied the engineering principles of crystal habit by directional crystallization to the fabrication of porous PVDF (polyvinylidene fluoride) membranes. Pores of low tortuosity and relatively high porosity (80-90%) were successfully fabricated by the directional crystallization of DMSO (dimethyl sulfoxide) under a temperature gradient imposed by the controlled movement of a sample toward a liquid nitrogen reservoir followed by subsequent solvent removal. Pore size was controlled across a wide range by mixing DMSO with dioxane. Notably, nanoporous structures could be prepared at a 1:1 mixing ratio, in which the multi-step crystallization of solvents restricted by highly concentrated solutes enabled the preparation of nanomembranes. The homogeneous dispersion of TiO2 nanoparticles into PVDF, which are often used to improve hydrophilicity and antifouling performance, was easily achieved by this method. This novel prep technology based on the directional crystallization of solvent mixtures is a potentially viable solution to the limitations of current porous materials research. PMID:23755679

  14. Ingrowth of Human Mesenchymal Stem Cells into Porous Silk Particle Reinforced Silk Composite Scaffolds: An In Vitro Study

    PubMed Central

    Rockwood, Danielle N.; Gil, Eun Seok; Park, Sang-Hyug; Kluge, Jonathan A.; Grayson, Warren; Bhumiratana, Sarindr; Rajkhowa, Rangam; Wang, Xungai; Kim, Sung Jun; Vunjak-Novakovic, Gordana; Kaplan, David L

    2010-01-01

    Silk fibroin protein is biodegradable and biocompatible, exhibiting excellent mechanical properties for various biomedical applications. However, porous 3D silk fibroin scaffolds, or silk sponges, usually fall short in matching the initial mechanical requirements for bone tissue engineering. In the present study, silk sponge matrices were reinforced with silk microparticles to generate protein-protein composite scaffolds with desirable mechanical properties for in vitro osteogenic tissue formation. It was found that increasing the silk microparticle loading led to a substantial increase in the scaffold compressive modulus from 0.3 MPa (nonreinforced) to 1.9 MPa for 1:2 (matrix:particle) reinforcement loading by dry mass. Biochemical, gene expression, and histological assays were employed to study the possible effects of increasing composite scaffold stiffness, due to microparticle reinforcement, on in vitro osteogenic differentiation of human mesenchymal stem cells (hMSCs). Increasing silk microparticle loading increased the osteogenic capability of hMSCs in the presence of bone morphogenic protein-2 (BMP-2) and other osteogenic factors in static culture for up to six weeks. The calcium adsorption increased dramatically with increasing loading, as observed from biochemical assays, histological staining, and microCT (?CT) analysis. Specifically, calcium content in the scaffolds increased by 0.57, 0.71, and 1.27 mg (per ?g of DNA) from 3 to 6 weeks for matrix to particle dry mass loading ratios of 1:0, 1:1 and 1:2, respectively. In addition, ?CT imaging revealed that at 6 weeks, bone volume fraction increased from 0.78% for nonreinforced to 7.1% and 6.7% for 1:1 and 1:2 loading, respectively. Our results support the hypothesis that scaffold stiffness may strongly influence the 3D in vitro differentiation capabilities of hMSCs, providing a means to improve osteogenic outcomes. PMID:20656075

  15. Improving osteointegration and osteogenesis of three-dimensional porous Ti6Al4V scaffolds by polydopamine-assisted biomimetic hydroxyapatite coating.

    PubMed

    Li, Yong; Yang, Wei; Li, Xiaokang; Zhang, Xing; Wang, Cairu; Meng, Xiangfei; Pei, Yifeng; Fan, Xiangli; Lan, Pingheng; Wang, Chunhui; Li, Xiaojie; Guo, Zheng

    2015-03-18

    Titanium alloys with various porous structures can be fabricated by advanced additive manufacturing techniques, which are attractive for use as scaffolds for bone defect repair. However, modification of the scaffold surfaces, particularly inner surfaces, is critical to improve the osteointegration of these scaffolds. In this study, a biomimetic approach was employed to construct polydopamine-assisted hydroxyapatite coating (HA/pDA) onto porous Ti6Al4V scaffolds fabricated by the electron beam melting method. The surface modification was characterized with the field emission scanning electron microscopy, energy dispersive spectroscopy, water contact angle measurement, and confocal laser scanning microscopy. Attachment and proliferation of MC3T3-E1 cells on the scaffold surface were significantly enhanced by the HA/pDA coating compared to the unmodified surfaces. Additionally, MC3T3-E1 cells grown on the HA/pDA-coated Ti6Al4V scaffolds displayed significantly higher expression of runt-related transcription factor-2, alkaline phosphatase, osteocalcin, osteopontin, and collagen type-1 compared with bare Ti6Al4V scaffolds after culture for 14 days. Moreover, microcomputed tomography analysis and Van-Gieson staining of histological sections showed that HA/pDA coating on surfaces of porous Ti6Al4V scaffolds enhanced osteointegration and significantly promoted bone regeneration after implantation in rabbit femoral condylar defects for 4 and 12 weeks. Therefore, this study provides an alternative to biofunctionalized porous Ti6Al4V scaffolds with improved osteointegration and osteogenesis functions for orthopedic applications. PMID:25711714

  16. Retention of Insulin-like Growth Factor I Bioactivity during Fabrication of Sintered Polymeric Scaffolds

    PubMed Central

    Clark, Amanda; Milbrandt, Todd A.; Hilt, J. Zach; Puleo, David A.

    2014-01-01

    The use of growth factors in tissue engineering offers an added benefit to cartilage regeneration. Growth factors, such as insulin-like growth factor I (IGF-I), increase cell proliferation and can therefore decrease the time it takes for cartilage tissue to regrow. In this study, IGF-I was released from poly(lactic-co-glycolic) acid (PLGA) scaffolds that were designed to have a decreased burst release often associated with tissue engineering scaffolds. The scaffolds were fabricated from IGF-I-loaded PLGA microspheres by a double emulsion (W1/O/W2) technique. The microspheres were then compressed, sintered at 49°C, and salt leached. The bioactivity of soluble IGF-I was verified after being heat treated at 37, 43, 45, 49, and 60°C. Additionally, the bioactivity of IGF-I was confirmed after being released from the sintered scaffolds. The triphasic release lasted 120 days resulting in 20%, 55% and 25% of the IGF-I being released during days 1-3, 4-58, and 59-120, respectively. Seeding bone marrow cells directly onto the IGF-I loaded scaffolds showed an increase in cell proliferation, based on DNA content, leading to an increased glycosaminoglycan (GAG) production. The present results demonstrated that IGF-I remains active after being incorporated into heat-treated scaffolds, further enhancing tissue regeneration possibilities. PMID:24565886

  17. Preparation of three-layered porous PLA/PEG scaffold: relationship between morphology, mechanical behavior and cell permeability.

    PubMed

    Scaffaro, R; Lopresti, F; Botta, L; Rigogliuso, S; Ghersi, G

    2016-02-01

    Interface tissue engineering (ITE) is used to repair or regenerate interface living tissue such as for instance bone and cartilage. This kind of tissues present natural different properties from a biological and mechanical point of view. With the aim to imitating the natural gradient occurring in the bone-cartilage tissue, several technologies and methods have been proposed over recent years in order to develop polymeric functionally graded scaffolds (FGS). In this study three-layered scaffolds with a pore size gradient were developed by melt mixing polylactic acid (PLA) and two water-soluble porogen agents: sodium chloride (NaCl) and polyethylene glycol (PEG). Pore dimensions were controlled by NaCl granulometry while PEG solvation created a micropores network within the devices. Scaffolds were characterized from a morphological and mechanical point of view in order to find a correlation between the preparation method, the pore architecture and compressive mechanical behavior. Biological tests were also performed in order to study the effect of pore size gradient on the permeation of different cell lines in co-culture. To imitate the physiological work condition, compressive tests were also performed in phosphate buffered saline (PBS) solution at 37°C. The presented preparation method permitted to prepare three-layered scaffolds with high control of porosity and pore size distribution. Furthermore mechanical behaviors were found to be strongly affected by pore architecture of tested devices as well as the permeation of osteoblast and fibroblast in-vitro. PMID:26410761

  18. Evaluation of the novel three-dimensional porous poly (L-lactic acid)/nano-hydroxyapatite composite scaffold.

    PubMed

    Huang, Jianghong; Xiong, Jianyi; Liu, Jianquan; Zhu, Weimin; Chen, Jielin; Duan, Li; Zhang, Jufeng; Wang, Daping

    2015-08-17

    To determine the optimal ratio of nano-hydroxyapatite (n-HA) to polylactic acid (PLLA) in the novel three-dimensional porous PLLA/n-HA composite scaffolds, low-temperature rapid prototyping technology was employed to fabricate the composite materials with different n-HA contents. Mechanical properties and degradation behaviors of the composites were examined, and the scaffold microstructure and n-HA dispersion were observed by scanning electron microscope (SEM). Mechanical tests demonstrated that the tensile strength of the composite material gradually decreased with an increase in n-HA content. When the n-HA content reached 20 wt%, the bending strength of the composite material peaked at 138.5 MPa. SEM images demonstrated that the optimal content of n-HA was 20 wt% as the largest interconnected pore size that can be seen, with a porosity as high as 80%. In vitro degradation experiments demonstrated that the pH value of the material containing solution gradually decreased in a time-dependent manner, with a simultaneous weakening of the mechanical properties. In vitro study using rat osteoblast cells showed that the composite scaffolds were biocompatible; the 20 wt% n-HA scaffold offered particular improvement to rat osteoblast cell adhesion and proliferation compared to other compositions. It was therefore concluded that 20 wt% n-HA is the optimal nano-hydroxyapatite (n-HA) to polylactic acid (PLLA) ratio, with promise for bone tissue engineering. PMID:26405972

  19. Mimic of the green fluorescent protein ?-barrel: photophysics and dynamics of confined chromophores defined by a rigid porous scaffold.

    PubMed

    Williams, Derek E; Dolgopolova, Ekaterina A; Pellechia, Perry J; Palukoshka, Andrei; Wilson, Thomas J; Tan, Rui; Maier, Josef M; Greytak, Andrew B; Smith, Mark D; Krause, Jeanette A; Shustova, Natalia B

    2015-02-18

    Chromophores with a benzylidene imidazolidinone core define the emission profile of commonly used biomarkers such as the green fluorescent protein (GFP) and its analogues. In this communication, artificially engineered porous scaffolds have been shown to mimic the protein ?-barrel structure, maintaining green fluorescence response and conformational rigidity of GFP-like chromophores. In particular, we demonstrated that the emission maximum in our artificial scaffolds is similar to those observed in the spectra of the natural GFP-based systems. To correlate the fluorescence response with a structure and perform a comprehensive analysis of the prepared photoluminescent scaffolds, (13)C cross-polarization magic angle spinning solid-state (CP-MAS) NMR spectroscopy, powder and single-crystal X-ray diffraction, and time-resolved fluorescence spectroscopy were employed. Quadrupolar spin-echo solid-state (2)H NMR spectroscopy, in combination with theoretical calculations, was implemented to probe low-frequency vibrational dynamics of the confined chromophores, demonstrating conformational restrictions imposed on the coordinatively trapped chromophores. Because of possible tunability of the introduced scaffolds, these studies could foreshadow utilization of the presented approach toward directing a fluorescence response in artificial GFP mimics, modulating a protein microenvironment, and controlling nonradiative pathways through chromophore dynamics. PMID:25654319

  20. Electrodeposition of manganese oxide nanosheets on a continuous three-dimensional nickel porous scaffold for high performance electrochemical capacitors

    NASA Astrophysics Data System (ADS)

    Xiao, Junwu; Yang, Shengxiong; Wan, Lian; Xiao, Fei; Wang, Shuai

    2014-01-01

    It's desirable to design an ideal three-dimensional (3D) interpenetrating network as the current collector for providing efficient ion and electron transport. Herein, we report a facile method to fabricate a novel continuous 3D Ni porous nanoarchitecture via the reduction of Ni(OH)2 nanowall precursors. The as-formed continuous 3D Ni porous network as the conductive scaffold can support a highly electrolytic accessible surface area of redox active MnO2 nanosheets, and provide reliable electrical connections to the MnO2 layers. In comparison with the planar conducting substrates, this 3D scaffold not only can increase the mass loading of MnO2 active materials, but also facilitate the facile transport of electron and electrolyte ion. Thus, the 3D (MnO2/Ni) electrode exhibited higher specific capacitance (1169.6 F g-1 at 2 A g-1, closed to the theoretical value) and better long-term cyclability (only ˜5% loss after 1000 cycles) than that on the planar conducting substrate under the identical electrodeposition condition (611.6 F g-1 at 2 A g-1 and around 20% loss after 1000 cycles). These results suggest that such 3D Ni porous architecture is a promising current collector for high-performance electrochemical capacitor.

  1. Biocompatibility and bone-repairing effects: comparison between porous poly-lactic-co-glycolic acid and nano-hydroxyapatite/poly(lactic acid) scaffolds.

    PubMed

    Zong, Chen; Qian, Xiaodan; Tang, Zihua; Hu, Qinghong; Chen, Jiarong; Gao, Changyou; Tang, Ruikang; Tong, Xiangmin; Wang, Jinfu

    2014-06-01

    Copolymer composite scaffolds and bioceramic/polymer composite scaffolds are two representative forms of composite scaffolds used for bone tissue engineering. Studies to compare biocompatibility and bone-repairing effects between these two scaffolds are significant for selecting or improving the scaffold for clinical application. We prepared two porous scaffolds comprising poly-lactic-acid/poly-glycolic-acid (PLGA) and poly-lactic-acid/nano-hydroxyapatite (nHAP/PLA) respectively, and examined their biocompatibility with human bone marrow-derived mesenchymal stem cells (hMSCs) through evaluating adhesion, proliferation and osteogenic differentiation potentials of hMSCs in the scaffold. Then, the PLGA scaffold with hMSCs (PM construct) and the nHAP/PLA scaffold with hMSCs (HPM construct) were transplanted into the rat calvarial defect areas to compare their effects on the bone reconstruction. The results showed that the nHAP/PLA scaffold was in favor of adhesion, matrix deposition and osteogenic differentiation of hMSCs. For in vivo transplantation, both HPM and PM constructs led to mineralization and osteogenesis in the defect area of rat. However, the area grafted with PM construct showed a better formation of mature bone than that with HPM construct. In addition, the evaluation of in vitro and in vivo degradation indicated that the degradation rate of nHAP/PLA scaffold was much lower than that of PLGA scaffold. It is inferred that the lower degradation of nHAP/PLA scaffold should result in its inferior bone reconstruction in rat calvaria. Therefore, the preparation of an ideal composite scaffold for bone tissue engineering should be taken into account of the balance between its biocompatibility, degradation rate, osteoconductivity and mechanical property. PMID:24749403

  2. Microfabrication of complex porous tissue engineering scaffolds using 3D projection stereolithography

    PubMed Central

    Gauvin, Robert; Chen, Ying-Chieh; Lee, Jin Woo; Soman, Pranav; Zorlutuna, Pinar; Nichol, Jason W.; Bae, Hojae; Chen, Shaochen; Khademhosseini, Ali

    2013-01-01

    The success of tissue engineering will rely on the ability to generate complex, cell seeded three-dimensional (3D) structures. Therefore, methods that can be used to precisely engineer the architecture and topography of scaffolding materials will represent a critical aspect of functional tissue engineering. Previous approaches for 3D scaffold fabrication based on top-down and process driven methods are often not adequate to produce complex structures due to the lack of control on scaffold architecture, porosity, and cellular interactions. The proposed projection stereolithography (PSL) platform can be used to design intricate 3D tissue scaffolds that can be engineered to mimic the microarchitecture of tissues, based on computer aided design (CAD). The PSL system was developed, programmed and optimized to fabricate 3D scaffolds using gelatin methacrylate (GelMA). Variation of the structure and prepolymer concentration enabled tailoring the mechanical properties of the scaffolds. A dynamic cell seeding method was utilized to improve the coverage of the scaffold throughout its thickness. The results demonstrated that the interconnectivity of pores allowed for uniform human umbilical vein endothelial cells (HUVECs) distribution and proliferation in the scaffolds, leading to high cell density and confluency at the end of the culture period. Moreover, immunohistochemistry results showed that cells seeded on the scaffold maintained their endothelial phenotype, demonstrating the biological functionality of the microfabricated GelMA scaffolds. PMID:22365811

  3. The generation of biomolecular patterns in highly porous collagen-GAG scaffolds using direct photolithography

    PubMed Central

    Martin, Teresa A.; Caliari, Steven R.; Williford, Paul D.; Harley, Brendan A.; Bailey, Ryan C.

    2014-01-01

    The extracellular matrix (ECM) is a complex organization of structural proteins found within tissues and organs. Heterogeneous tissues with spatially and temporally modulated properties play an important role in organism physiology. Here we present a benzophenone (BP) based direct, photolithographic approach to spatially pattern solution phase biomolecules within collagen-GAG (CG) scaffolds and demonstrate creation of a wide range of patterns composed of multiple biomolecular species in a manner independent from scaffold fabrication steps. We demonstrate the ability to immobilize biomolecules at surface densities of up to 1000 ligands per square micron on the scaffold strut surface and to depths limited by the penetration depth of the excitation source into the scaffold structure. Importantly, while BP photopatterning does further crosslink the CG scaffold, evidenced by increased mechanical properties and collagen crystallinity, it does not affect scaffold microstructural or compositional properties or negatively influence cell adhesion, viability, or proliferation. We show that covalently photoimmobilized fibronectin within a CG scaffold significantly increases the speed of MC3T3-E1 cell attachment relative to the bare CG scaffold or non-specifically adsorbed fibronectin, suggesting that this approach can be used to improve scaffold bioactivity. Our findings, on the whole, establish the use of direct, BP photolithography as a methodology for covalently incorporating activity-improving biochemical cues within 3D collagen biomaterial scaffolds with spatial control over biomolecular deposition. PMID:21397322

  4. Novel Modeling Approach to Generate a Polymeric Nanofiber Scaffold for Salivary Gland Cells

    PubMed Central

    Jean-Gilles, Riffard; Soscia, David; Sequeira, Sharon; Melfi, Michael; Gadre, Anand; Castracane, James; Larsen, Melinda

    2011-01-01

    Background Electrospun nanofibers have been utilized in many biomedical applications as biomimetics of extracellular matrix proteins that promote self-organization of cells into 3D tissue constructs. As progress towards an artificial salivary gland tissue construct, we prepared nanofiber scaffolds using PLGA, a biodegradable and biocompatible material. Method of Approach We used electrospinning to prepare nanofiber scaffolds using PLGA with both DMF and HFIP as solvents. Using a design of experiment (DOE) approach, system and process parameters were optimized concurrently and their effects on the diameter of the resulting fibers were computed into a single model. A transfer function was used to reproducibly produce nanofibers of a defined diameter, which was confirmed by SEM. The mouse salivary gland epithelial cell line, SIMS, was seeded on the nanofiber scaffolds, and morphology, cell proliferation, and viability were assayed. Results Varying two or more parameters simultaneously yielded trends diverging from the linear response predicted by previous studies. Comparison of two solvents revealed that the diameter of PLGA nanofibers generated using HFIP is less sensitive to changes in the system and process parameters than are fibers generated using DMF. Inclusion of NaCl reduced morphological inconsistencies and minimized process variability. The resulting nanofiber scaffolds supported attachment, survival and cell proliferation of a mouse salivary gland epithelial cell line. In comparison with glass and flat PLGA films, the nanofibers promoted self-organization of the salivary gland cells into 3D cell clusters, or aggregates. Conclusions These data indicate that nanofiber scaffolds promote salivary gland cell organization, and suggest that a nanofiber scaffold could provide a platform for engineering of an artificial salivary gland tissue construct. This study additionally provides a method for efficient production of nanofiber scaffolds for general application in tissue engineering. PMID:22229076

  5. Novel Modeling Approach to Generate a Polymeric Nanofiber Scaffold for Salivary Gland Cells.

    PubMed

    Jean-Gilles, Riffard; Soscia, David; Sequeira, Sharon; Melfi, Michael; Gadre, Anand; Castracane, James; Larsen, Melinda

    2010-08-01

    BACKGROUND: Electrospun nanofibers have been utilized in many biomedical applications as biomimetics of extracellular matrix proteins that promote self-organization of cells into 3D tissue constructs. As progress towards an artificial salivary gland tissue construct, we prepared nanofiber scaffolds using PLGA, a biodegradable and biocompatible material. METHOD OF APPROACH: We used electrospinning to prepare nanofiber scaffolds using PLGA with both DMF and HFIP as solvents. Using a design of experiment (DOE) approach, system and process parameters were optimized concurrently and their effects on the diameter of the resulting fibers were computed into a single model. A transfer function was used to reproducibly produce nanofibers of a defined diameter, which was confirmed by SEM. The mouse salivary gland epithelial cell line, SIMS, was seeded on the nanofiber scaffolds, and morphology, cell proliferation, and viability were assayed. RESULTS: Varying two or more parameters simultaneously yielded trends diverging from the linear response predicted by previous studies. Comparison of two solvents revealed that the diameter of PLGA nanofibers generated using HFIP is less sensitive to changes in the system and process parameters than are fibers generated using DMF. Inclusion of NaCl reduced morphological inconsistencies and minimized process variability. The resulting nanofiber scaffolds supported attachment, survival and cell proliferation of a mouse salivary gland epithelial cell line. In comparison with glass and flat PLGA films, the nanofibers promoted self-organization of the salivary gland cells into 3D cell clusters, or aggregates. CONCLUSIONS: These data indicate that nanofiber scaffolds promote salivary gland cell organization, and suggest that a nanofiber scaffold could provide a platform for engineering of an artificial salivary gland tissue construct. This study additionally provides a method for efficient production of nanofiber scaffolds for general application in tissue engineering. PMID:22229076

  6. A simple method for the synthesis of porous polymeric vesicles and their application as MR contrast agents

    PubMed Central

    Yan, Lesan; Higbee, Elizabeth; Tsourkas, Andrew

    2015-01-01

    Because of their low membrane permeability the use of polymeric vesicles in certain drug delivery and molecular imaging applications and as bioreactors is less than ideal. Here, we report a simple method to prepare porous polymeric vesicles that possess high membrane permeability. Specifically, porous vesicles were produced from the aqueous assembly of the diblock copolymer PEG-PBD, and the triblock copolymer PEG-PPO-PEG. It was found that PEG-PPO-PEG-doped polymersomes exhibited improved membrane permeability to molecules less than 5 kDa. Further, these porous vesicles retained molecules ?10 kDa within their aqueous interiors with no significant leakage. To demonstrate its application, highly efficient magnetic resonance contrast agents were produced from porous polymersomes by encapsulating macromolecules labeled with gadolinium. Due to a fast water exchange rate with surrounding bulk water, these paramagnetic porous polymersomes exhibited higher r1 relaxivity compared with Gd-encapsulated vesicles with no pores. Due to their simplicity, the porous polymersomes prepared with this method are expected to have additional useful applications. PMID:26693022

  7. Novel real function based method to construct heterogeneous porous scaffolds and additive manufacturing for use in medical engineering.

    PubMed

    Yang, Nan; Tian, Yanling; Zhang, Dawei

    2015-11-01

    Heterogeneous porous scaffolds have important applications in biomedical engineering, as they can mimic the structures of natural tissues to achieve the corresponding properties. Here, we introduce a new and easy to implement real function based method for constructing complex, heterogeneous porous structures, including hybrid structures, stochastic structures, functionally gradient structures, and multi-scale structures, or their combinations (e.g., hybrid multi-scale structures). Based on micro-CT data, a femur-mimetic structure with gradient morphology was constructed using our method and fabricated using stereolithography. Results showed that our method could generate gradient porosity or gradient specific surfaces and be sufficiently flexible for use with micro-CT data and additive manufacturing (AM) techniques. PMID:26320819

  8. The scale-up of a tissue engineered porous hydroxyapatite polymer composite scaffold for use in bone repair: an ovine femoral condyle defect study.

    PubMed

    Tayton, Edward; Purcell, Matthew; Smith, James O; Lanham, Stuart; Howdle, Steven M; Shakesheff, Kevin M; Goodship, Allen; Blunn, Gordon; Fowler, Darren; Dunlop, Douglas G; Oreffo, Richard O C

    2015-04-01

    The development of an osteogenic bone graft substitute has important practical and cost implications in many branches of medicine where bone regeneration is required. Previous in vitro and small animal (murine) in vivo studies highlighted a porous hydroxyapatite/poly (DL-lactic acid) composite scaffold in combination with skeletal stem cells (SSCs) as a potential bone graft substitute candidate. The aim of the current study was to scale up the bone cell-scaffold construct to large animals and examine the potential for repair of a critical-sized defect via an ovine model. SSC seeded scaffolds (and unseeded scaffold controls) were implanted bilaterally into ovine femoral condyle critical defects for 3 months. A parallel in vitro analysis of ovine SSC seeded scaffolds was also performed. Post mortem mechanical indentation testing showed the bone strengths of the defect sites were 20% (controls) and 11% (SSC seeded scaffolds) those of normal cancellous bone (p < 0.01). MicroCT analysis demonstrated new bone formation within all defects with a mean increase of 13.4% in the control scaffolds over the SSC seeded scaffolds (p = 0.14). Histological examination confirmed these findings, with enhanced quality new bone within the control defects. This study highlights important issues and steps to overcome in scale-up and translation of tissue engineered products. The scaffold demonstrated encouraging results as an osteoconductive matrix; however, further work is required with cellular protocols before any human trials. PMID:25044983

  9. Seeding of mesenchymal stem cells into inner part of interconnected porous biodegradable scaffold by a new method with a filter paper.

    PubMed

    Yamanaka, Katsuyuki; Yamamoto, Katsushi; Sakai, Yuhiro; Suda, Youko; Shigemitsu, Yusuke; Kaneko, Tadashi; Kato, Koichi; Kumagai, Tomohiro; Kato, Yukio

    2015-01-01

    An appropriate physical support provided by scaffolds creates a supportive environment that directs proliferation and differentiation of stem cells. However, it is difficult to homogenously inoculate stem cells into the inner part of scaffolds at high cell densities. In this study, mesenchymal stem cells were seeded into a hydroxyapatite/poly (D, L-lactic-co-glycolic acid) (HAP/PLGA) scaffold that had enough mechanical strength and porous 3-D structure. With an aid of a filter paper placed under the bottom of a HAP/PLGA block, the cells suspended in a culture medium flowed from the top to the bottom through interconnected pores in the scaffold, and distributed almost homogenously, as compared to cell distribution near the surface of the block by the conventional method using centrifugation or reduced pressure. This simple method with a filter paper may be useful in preparation of cell-scaffold complexes for tissue engineering. PMID:25748462

  10. Development of highly porous scaffolds based on bioactive silicates for dental tissue engineering

    SciTech Connect

    Goudouri, O.M.; Theodosoglou, E.; Kontonasaki, E.; Will, J.; Chrissafis, K.; Koidis, P.; Paraskevopoulos, K.M.; Boccaccini, A.R.

    2014-01-01

    Graphical abstract: - Highlights: • Synthesis of an Mg-based glass-ceramic via the sol–gel technique. • The heat treatment of the glass-ceramic promoted the crystallization of akermanite. • Akermanite scaffolds coated with gelatin were successfully fabricated. • An HCAp layer was developed on the surface of all scaffolds after 9 days in SBF. - Abstract: Various scaffolding materials, ceramics and especially Mg-based ceramic materials, including akermanite (Ca{sub 2}MgSi{sub 2}O{sub 7}) and diopside (CaMgSi{sub 2}O{sub 6}), have attracted interest for dental tissue regeneration because of their improved mechanical properties and controllable biodegradation. The aim of the present work was the synthesis of an Mg-based glass-ceramic, which would be used for the construction of workable akermanite scaffolds. The characterization of the synthesized material was performed by Fourier Transform Infrared Spectroscopy (FTIR) X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM). Finally, the apatite forming ability of the scaffolds was assessed by immersion in simulated body fluid. The scaffolds were fabricated by the foam replica technique and were subsequently coated with gelatin to provide a functional surface for increased cell attachment. Finally, SEM microphotographs and FTIR spectra of the scaffolds after immersion in SBF solution indicated the inorganic bioactive character of the scaffolds suitable for the intended applications in dental tissue engineering.

  11. Preparation of tissue engineering porous scaffold with poly(lactic acid) and polyethylene glycol solution blend by solvent-casting/particulate-leaching

    NASA Astrophysics Data System (ADS)

    Huang, Ran; Zhu, Xiaomin; Zhao, Tingting; Wan, Ajun

    2014-12-01

    Polyethylene glycol/poly(lactic acid) solution blend is employed as the raw materials to prepare porous scaffold of potential usage in tissue engineering. The solution blend can be naturally introduced in the classical solvent casting/particular leaching technique in porous matrix preparation. The PEG presence is to modify the degradation behavior of scaffolds to fit particular requirements in tissue engineering. The porous matrix of PEG/PLA with various weight ratios are made with pores size ˜ 250 ? m. The SEM characterizations have been done to investigate the porous morphology of products, the results indicate that though with the clear semi-miscibility feature of PEG/PLA blends, the macro-structure is not significantly affected by the PEG content percentage. The degradation results show an enhanced weight loss rate with the presence of PEG as expected.

  12. In vivo acute and humoral response to three-dimensional porous soy protein scaffolds.

    PubMed

    Chien, Karen B; Aguado, Brian A; Bryce, Paul J; Shah, Ramille N

    2013-11-01

    Increasing interest in using soy biomaterials for tissue engineering applications has prompted investigation into the in vivo biocompatibility of soy implants. In this study, the biocompatibility of soy protein scaffolds fabricated using freeze-drying and 3-D printing was assessed using a subcutaneous implant model in BALB/c mice. The main objectives of this study were: (1) to compare soy protein with bovine collagen, a well-characterized natural protein implant, by implanting scaffolds of the same protein weight, and (2) to observe the effects of soy scaffold microstructure and amount of protein loading, which also alters the degradation properties, on the acute and humoral immune responses towards soy. Results showed that freeze-dried soy scaffolds fully degraded after 14 days, whereas collagen scaffolds (of the same protein weight) remained intact for 56 days. Furthermore, Masson's trichrome staining showed little evidence of damage or fibrosis at the soy implant site. Scaffolds of higher soy protein content, however, were still present after 56 days. H&E staining revealed that macrophage infiltration was hindered in the denser bioplotted soy scaffolds, causing slower degradation. Analysis of soy-specific antibodies in mouse serum after implantation revealed levels of IgG1 that correlated with higher scaffold weight and protein density. However, no soy-specific IgE was detected, indicating the absence of an allergic response to the soy implants. These results demonstrate that soy protein could be an acceptable biocompatible implant for tissue regeneration, and that scaffold porosity, soy protein density and scaffold degradation rate significantly affect the acute and humoral immune response. PMID:23851173

  13. Fabrication of three-dimensional porous scaffolds with controlled filament orientation and large pore size via an improved E-jetting technique.

    PubMed

    Li, Jin Lan; Cai, Yan Li; Guo, Yi Lin; Fuh, Jerry Ying Hsi; Sun, Jie; Hong, Geok Soon; Lam, Ruey Na; Wong, Yoke San; Wang, Wilson; Tay, Bee Yen; Thian, Eng San

    2014-05-01

    Biodegradable polymeric scaffolds have been widely used in tissue engineering as a platform for cell proliferation and subsequent tissue regeneration. Conventional microextrusion methods for three-dimensional (3D) scaffold fabrication were limited by their low resolution. Electrospinning, a form of electrohydrodynamic (EHD) printing, is an attractive method due to its capability of fabricating high-resolution scaffolds at the nanometer/micrometer scale level. However, the scaffold was composed of randomly orientated filaments which could not guide the cells in a specific direction. Furthermore, the pores of the electrospun scaffold were small, thus preventing cell infiltration. In this study, an alternative EHD jet printing (E-jetting) technique has been developed and employed to fabricate 3D polycaprolactone (PCL) scaffolds with desired filament orientation and pore size. The effect of PCL solution concentration was evaluated. Results showed that solidified filaments were achieved at concentration >70% (w/v). Uniform filaments of diameter 20 ?m were produced via the E-jetting technique, and X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopic analyses revealed that there was no physicochemical changes toward PCL. Scaffold with a pore size of 450 ?m and porosity level of 92%, was achieved. A preliminary in vitro study illustrated that live chondrocytes were attaching on the outer and inner surfaces of collagen-coated E-jetted PCL scaffolds. E-jetted scaffolds increased chondrocytes extracellular matrix secretion, and newly formed matrices from chondrocytes contributed significantly to the mechanical strength of the scaffolds. All these results suggested that E-jetting is an alternative scaffold fabrication technique, which has the capability to construct 3D scaffolds with aligned filaments and large pore sizes for tissue engineering applications. PMID:24155124

  14. Use of Clotted Human Plasma and Aprotinin in Skin Tissue Engineering: A Novel Approach to Engineering Composite Skin on a Porous Scaffold.

    PubMed

    Paul, Michelle; Kaur, Pritinder; Herson, Marisa; Cheshire, Perdita; Cleland, Heather; Akbarzadeh, Shiva

    2015-10-01

    Tissue-engineered composite skin is a promising therapy for the treatment of chronic and acute wounds, including burns. Providing the wound bed with a dermal scaffold populated by autologous dermal and epidermal cellular components can further entice host cell infiltration and vascularization to achieve permanent wound closure in a single stage. However, the high porosity and the lack of a supportive basement membrane in most commercially available dermal scaffolds hinders organized keratinocyte proliferation and stratification in vitro and may delay re-epithelization in vivo. The objective of this study was to develop a method to enable the in vitro production of a human skin equivalent (HSE) that included a porous scaffold and dermal and epidermal cells expanded ex vivo, with the potential to be used for definitive treatment of skin defects in a single procedure. A collagen-glycosaminoglycan dermal scaffold (Integra(®)) was populated with adult fibroblasts. A near-normal skin architecture was achieved by the addition of coagulated human plasma to the fibroblast-populated scaffold before seeding cultured keratinocytes. This resulted in reducing scaffold pore size and improving contact surfaces. Skin architecture and basement membrane formation was further improved by the addition of aprotinin (a serine protease inhibitor) to the culture media to inhibit premature clot digestion. Histological assessment of the novel HSE revealed expression of keratin 14 and keratin 10 similar to native skin, with a multilayered neoepidermis morphologically comparable to human skin. Furthermore, deposition of collagen IV and laminin-511 were detected by immunofluorescence, indicating the formation of a continuous basement membrane at the dermal-epidermal junction. The proposed method was efficient in producing an in vitro near native HSE using the chosen off-the-shelf porous scaffold (Integra). The same principles and promising outcomes should be applicable to other biodegradable porous scaffolds, combined with autologous cells, for use in wound treatment. PMID:25996837

  15. Bacterial inhibition potential of 3D rapid-prototyped magnesium-based porous composite scaffolds--an in vitro efficacy study.

    PubMed

    Ma, Rui; Lai, Yu-xiao; Li, Long; Tan, Hong-lue; Wang, Jia-li; Li, Ye; Tang, Ting-ting; Qin, Ling

    2015-01-01

    Bone infections are common in trauma-induced open fractures with bone defects. Therefore, developing anti-infection scaffolds for repairing bone defects is desirable. This study develoepd novel Mg-based porous composite scaffolds with a basal matrix composed of poly(lactic-co-glycolicacid) (PLGA) and tricalcium phosphate (TCP). A unique low-temperature rapid prototyping technology was used to fabricate the scaffolds, including PLGA/TCP (PT), PLGA/TCP/5%Mg (PT5M), PLGA/TCP/10%Mg (PT10M), and PLGA/TCP/15%Mg (PT15M). The bacterial adhesion and biofilm formation of Staphylococcus aureus were evaluated. The results indicated that the Mg-based scaffolds significantly inhibited bacterial adhesion and biofilm formation compared to PT, and the PT10M and PT15M exhibited significantly stronger anti-biofilm ability than PT5M. In vitro degratation tests revealed that the degradation of the Mg-based scaffolds caused an increase of pH, Mg(2+) concentration and osmolality, and the increased pH may be one of the major contributing factors to the antibacterial function of the Mg-based scaffolds. Additionally, the PT15M exhibited an inhibitory effect on cell adhesion and proliferation of MC3T3-E1 cells. In conclusion, the PLGA/TCP/Mg scaffolds could inhibit bacterial adhesion and biofilm formation, and the PT10M scaffold was considered to be an effective composition with considerable antibacterial ability and good cytocompatibility. PMID:26346217

  16. Bacterial inhibition potential of 3D rapid-prototyped magnesium-based porous composite scaffolds–an in vitro efficacy study

    PubMed Central

    Ma, Rui; Lai, Yu-xiao; Li, Long; Tan, Hong-lue; Wang, Jia-li; Li, Ye; Tang, Ting-ting; Qin, Ling

    2015-01-01

    Bone infections are common in trauma-induced open fractures with bone defects. Therefore, developing anti-infection scaffolds for repairing bone defects is desirable. This study develoepd novel Mg-based porous composite scaffolds with a basal matrix composed of poly(lactic-co-glycolicacid) (PLGA) and tricalcium phosphate (TCP). A unique low-temperature rapid prototyping technology was used to fabricate the scaffolds, including PLGA/TCP (PT), PLGA/TCP/5%Mg (PT5M), PLGA/TCP/10%Mg (PT10M), and PLGA/TCP/15%Mg (PT15M). The bacterial adhesion and biofilm formation of Staphylococcus aureus were evaluated. The results indicated that the Mg-based scaffolds significantly inhibited bacterial adhesion and biofilm formation compared to PT, and the PT10M and PT15M exhibited significantly stronger anti-biofilm ability than PT5M. In vitro degratation tests revealed that the degradation of the Mg-based scaffolds caused an increase of pH, Mg2+ concentration and osmolality, and the increased pH may be one of the major contributing factors to the antibacterial function of the Mg-based scaffolds. Additionally, the PT15M exhibited an inhibitory effect on cell adhesion and proliferation of MC3T3-E1 cells. In conclusion, the PLGA/TCP/Mg scaffolds could inhibit bacterial adhesion and biofilm formation, and the PT10M scaffold was considered to be an effective composition with considerable antibacterial ability and good cytocompatibility. PMID:26346217

  17. The promotion of angiogenesis induced by three-dimensional porous beta-tricalcium phosphate scaffold with different interconnection sizes via activation of PI3K/Akt pathways

    PubMed Central

    Xiao, Xin; Wang, Wei; Liu, Dong; Zhang, Haoqiang; Gao, Peng; Geng, Lei; Yuan, Yulin; Lu, Jianxi; Wang, Zhen

    2015-01-01

    The porous architectural characteristics of biomaterials play an important role in scaffold revascularization. However, no consensus exists regarding optimal interconnection sizes for vascularization and its scaffold bioperformance with different interconnection sizes. Therefore, a series of disk-type beta-tricalcium phosphates with the same pore sizes and variable interconnections were produced to evaluate how the interconnection size influenced biomaterial vascularization in vitro and in vivo. We incubated human umbilical vein endothelial cells on scaffolds with interconnections of various sizes. Results showed that scaffolds with a 150??m interconnection size ameliorated endothelial cell function evidenced by promoting cell adhesion and migration, increasing cell proliferation and enhancing expression of platelet-endothelial cell adhesion molecules and vascular endothelial growth factor. In vivo study was performed on rabbit implanted with scaffolds into the bone defect on femoral condyles. Implantation with scaffolds with 150??m interconnection size significantly improved neovascularization as shown by micro-CT as compared to scaffolds with 100 and 120??m interconnection sizes. Moreover, the aforementioned positive effects were abolished by blocking PI3K/Akt/eNOS pathway with LY-294002. Our study explicitly demonstrates that the scaffold with 150??m interconnection size improves neovascularization via the PI3K/Akt pathway and provides a target for biomaterial inner structure modification to attain improved clinical performance in implant vascularization. PMID:25797242

  18. The promotion of angiogenesis induced by three-dimensional porous beta-tricalcium phosphate scaffold with different interconnection sizes via activation of PI3K/Akt pathways

    NASA Astrophysics Data System (ADS)

    Xiao, Xin; Wang, Wei; Liu, Dong; Zhang, Haoqiang; Gao, Peng; Geng, Lei; Yuan, Yulin; Lu, Jianxi; Wang, Zhen

    2015-03-01

    The porous architectural characteristics of biomaterials play an important role in scaffold revascularization. However, no consensus exists regarding optimal interconnection sizes for vascularization and its scaffold bioperformance with different interconnection sizes. Therefore, a series of disk-type beta-tricalcium phosphates with the same pore sizes and variable interconnections were produced to evaluate how the interconnection size influenced biomaterial vascularization in vitro and in vivo. We incubated human umbilical vein endothelial cells on scaffolds with interconnections of various sizes. Results showed that scaffolds with a 150 ?m interconnection size ameliorated endothelial cell function evidenced by promoting cell adhesion and migration, increasing cell proliferation and enhancing expression of platelet-endothelial cell adhesion molecules and vascular endothelial growth factor. In vivo study was performed on rabbit implanted with scaffolds into the bone defect on femoral condyles. Implantation with scaffolds with 150 ?m interconnection size significantly improved neovascularization as shown by micro-CT as compared to scaffolds with 100 and 120 ?m interconnection sizes. Moreover, the aforementioned positive effects were abolished by blocking PI3K/Akt/eNOS pathway with LY-294002. Our study explicitly demonstrates that the scaffold with 150 ?m interconnection size improves neovascularization via the PI3K/Akt pathway and provides a target for biomaterial inner structure modification to attain improved clinical performance in implant vascularization.

  19. A combinatorial variation in surface chemistry and pore size of three-dimensional porous poly(?-caprolactone) scaffolds modulates the behaviors of mesenchymal stem cells.

    PubMed

    Zhao, Yingdi; Tan, Ke; Zhou, Yan; Ye, Zhaoyang; Tan, Wen-Song

    2016-02-01

    Biomaterial properties play significant roles in controlling cellular behaviors. The objective of the present study was to investigate how pore size and surface chemistry of three-dimensional (3D) porous scaffolds regulate the fate of mesenchymal stem cells (MSCs) in vitro in combination. First, on poly(?-caprolactone) (PCL) films, the hydrolytic treatment was found to stimulate the adhesion, spreading and proliferation of human MSCs (hMSCs) in comparison with pristine films, while the aminolysis showed mixed effects. Then, 3D porous PCL scaffolds with varying pore sizes (100-200?m, 200-300?m and 300-450?m) were fabricated and subjected to either hydrolysis or aminolysis. It was found that a pore size of 200-300?m with hydrolysis in 3D scaffolds was the most favorable condition for growth of hMSCs. Importantly, while a pore size of 200-300?m with hydrolysis for 1h supported the best osteogenic differentiation of hMSCs, the chondrogenic differentiation was greatest in scaffolds with a pore size of 300-450?m and treated with aminolysis for 1h. Taken together, these results suggest that surface chemistry and pore size of 3D porous scaffolds may potentially have a synergistic impact on the behaviors of MSCs. PMID:26652364

  20. Uncultured Marrow Mononuclear Cells Delivered Within Fibrin Glue Hydrogels to Porous Scaffolds Enhance Bone Regeneration Within Critical-Sized Rat Cranial Defects

    PubMed Central

    Kretlow, James D.; Spicer, Patrick P.; Jansen, John A.; Vacanti, Charles A.; Kasper, F. Kurtis

    2010-01-01

    For bone tissue engineering, the benefits of incorporating mesenchymal stem cells (MSCs) into porous scaffolds are well established. There is, however, little consensus on the effects of or need for MSC handling ex vivo. Culture and expansion of MSCs adds length and cost, and likely increases risk associated with treatment. We evaluated the effect of using uncultured bone marrow mononuclear cells (bmMNCs) encapsulated within fibrin glue hydrogels and seeded into porous scaffolds to regenerate bone over 12 weeks in an 8-mm-diameter, critical-sized rat cranial defect. A full factorial experimental design was used to evaluate bone formation within model poly(L-lactic acid) and corraline hydroxyapatite scaffolds with or without platelet-rich plasma (PRP) and bmMNCs. Mechanical push-out testing, microcomputed tomographical analyses, and histology were performed. PRP showed no benefit for bone formation. Cell-laden poly(L-lactic acid) scaffolds without PRP required significantly greater force to displace from surrounding tissues than control (cell-free) scaffolds, but no differences were observed during push-out testing of coral scaffolds. For bone volume formation as analyzed by microcomputed tomography, significant positive overall effects were observed with bmMNC incorporation. These data suggest that bmMNCs may provide therapeutic advantages in bone tissue engineering applications without the need for culture, expansion, and purification. PMID:20715884

  1. Fabrication of long-acting drug release property of hierarchical porous bioglasses/polylactic acid fibre scaffolds for bone tissue engineering.

    PubMed

    Wang, Dan; Lin, Huiming; Jiang, Jingjie; Jin, Qumei; Li, Lei; Dong, Yan; Qu, Fengyu

    2015-04-01

    Hierarchical porous fibre scaffolds with mesoporous bioglasses (MBGs) and polylactic acid (PLA) were successfully fabricated by the electrospinning method. These compound scaffolds possess macropores with sizes of about 100 nm because of the solvent evaporation from the fibre and the mesoporous structure ( ?4.0 nm) originated from MBGs. The biomineralisation ability was investigated in simulated body fluid. The fibre structure is beneficial for inducing the growth of hydroxyapatite. In addition, compared with pure MBGs, the materials (MP-1 and MP-2) exhibit a long-acting drug release process up to 140 h and the drug release process corresponds with the Fickian diffusion mechanism. With the special fibre morphology and the hierarchical porous structure, the MBGs/PLA fibre scaffolds are expected to have potential application for bone tissue repair and regeneration. PMID:25829170

  2. Porous surface structure of biocompatible implants and tissue scaffolds base of titanium and nitinol synthesized SLS/M methods

    NASA Astrophysics Data System (ADS)

    Shishkovsky, I.; Sherbakov, V.; Petriv, A.; Kuznetsov, M.; Morozov, Yu.; Volova, L.; Barikov, I.; Fakeev, S.

    2007-06-01

    The objectives of these researches were to investigate the technical fundamentals of synthesizing high-strength biocompatible medical implants and tissue scaffolds made from nitinol or titanium using of Selective Laser Sintering/Melting (SLS/M). In particular, we had been identify the processing parameters and procedures necessary to successfully laser synthesize multi-material and functionally graded implants: the physical and mechanical properties, microstructure, and corrosion behavior of the resulting structures; the shape memory effect in porous layered nitinol structures made using laser synthesis. The comparative morphological and histological results of Selective Laser Sintering of porous titanium and nitinol implants are presented. Studies are conducted also on primary cultures of dermal fibroblasts and mesenchymal stromal human cells of the 4-18 passages. The principle possibility of long cultivating a bone marrow on the porous carrier-incubator from NiTi and titanium in vitro was determined. Sufficient understanding of laser synthesized titanium and nitinol structures to determine their suitability for future use as implants, resulting in superior tissue to implant fixation and minimally invasive surgical procedures, was developed.

  3. Decellular biological scaffold polymerized with PEDOT for improving peripheral nerve interface charge transfer.

    PubMed

    Frost, Christopher M; Cederna, Paul S; Martin, David C; Bong Sup Shim; Urbanchek, Melanie G

    2014-08-01

    Regenerative peripheral nerve interfaces (RPNIs) are for signal transfer between peripheral nerves inside the body to controllers for motorized prosthetics external to the body. Within the residual limb of an amputee, surgical construction of a RPNI connects a remaining peripheral nerve and spare muscle. Nerve signals become concentrated within the RPNI. Currently metal electrodes implanted on the RPNI muscle transfer signals but scarring around metal electrodes progressively diminishes charge transfer. Engineered materials may benefit RPNI signal transfer across the neural interface if they lower the power and charge density of the biologically meaningful signals. Poly3,4-ethylenedioxythiophene (PEDOT) is known to mediate ionic potentials allowing excitation across a critical nerve gap. We hypothesize that the capacity of an interface material to conduct electron mediated current is significantly increased by polymerized coating of PEDOT. SIS was either used plain or after PEDOT coating by electrochemical polymerization. Muscle forces are a direct representation of stimulating current distribution within an RPNI. In situ muscle forces were measured for the same muscle by electrically stimulating: a) the muscle's innervating nerve, b) directly on the muscle, c) on plain SIS laid on the muscle, and d) on SIS polymerized with PEDOT laid on the muscle. Electro-chemically coating PEDOT on SIS resulted in a thin, flexible material. PEDOT coated SIS distributed electrical stimulation more efficiently than SIS alone. Conductive polymer containing biological material allowed ionic signal distribution within the RPNI like muscle at lower charge density. PMID:25569986

  4. ?-Cyclodextrin associated polymeric systems: Rheology, flow behavior in porous media and enhanced heavy oil recovery performance.

    PubMed

    Wei, Bing

    2015-12-10

    This proof of concept research evaluates an approach to improve the enhanced heavy oil recovery performance of conventional polymers. Three associated polymeric systems, based on hydrolyzed polyacrylamide, xanthan gum, and a novel hydrophobic copolymer, were proposed in this work. The results of the theoretically rheology study indicate that these systems offer superior viscoelasticity and pronounced shear-thinning behavior due to the "interlocking effect". As a result of the surfactant collaboration, the dynamic interfacial tension between oil and polymer solution can be reduced by two orders of magnitude. Sandpack flooding tests demonstrated the capacity of the developed systems in mobility control during propagating in porous media, and the adsorption behavior was represented by the thickness of the adsorbed layer. The relationship between microscopic efficiency and capillary number indicated that the associated systems can significantly reduce the residual oil saturation due to the synergistic effect of the mobility reduction and surface activity, and the overall recovery efficiency was raised by 2-20% OOIP compared to the baseline polymers. PMID:26428140

  5. Biofilms and extracellular polymeric substances mediate the transport of graphene oxide nanoparticles in saturated porous media.

    PubMed

    Jian-Zhou, He; Cheng-Cheng, Li; Deng-Jun, Wang; Zhou, Dong-Mei

    2015-12-30

    Understanding the fate and transport of graphene oxide nanoparticles (GONPs) in the subsurface environments is of crucial importance since they may pose potential risks to the environment and human health. However, little is known about the significance of biofilm on mobility of GONPs in the subsurface. Here we investigated the transport of GONPs in saturated sand coated with Bacillus subtilis (Gram-positive) and Pseudomonas putida (Gram-negative) biofilms, and their secreted extracellular polymeric substances (EPS) under environmentally relevant ionic strengths (1-50mM NaCl) at pH 7.2. Our results showed that irrespective of bacteria type, greater retention of GONPs occurred in biofilm-coated sand compared to clean sand, likely attributed to the increased surface roughness and physical straining. However, EPS showed negligible influence on GONPs transport, which was inconsistent with the findings in the presence of biofilms, while they exhibited comparable ?-potentials. The different retention phenotype of GONPs in the presence of EPS was induced by hydration effect and steric repulsion. A two-site kinetic retention model well-described the transport of GONPs in porous media covered with different surface coatings, which proves the applicability of mathematical model in predicting nanoparticles' mobility in the subsurface environments, when considering the potential effects of biofilm and EPS. PMID:26223021

  6. Chitosan-collagen porous scaffold and bone marrow mesenchymal stem cell transplantation for ischemic stroke

    PubMed Central

    Yan, Feng; Yue, Wei; Zhang, Yue-lin; Mao, Guo-chao; Gao, Ke; Zuo, Zhen-xing; Zhang, Ya-jing; Lu, Hui

    2015-01-01

    In this study, we successfully constructed a composite of bone marrow mesenchymal stem cells and a chitosan-collagen scaffold in vitro, transplanted either the composite or bone marrow mesenchymal stem cells alone into the ischemic area in animal models, and compared their effects. At 14 days after co-transplantation of bone marrow mesenchymal stem cells and the hitosan-collagen scaffold, neurological function recovered noticeably. Vascular endothelial growth factor expression and nestin-labeled neural precursor cells were detected in the ischemic area, surrounding tissue, hippocampal dentate gyrus and subventricular zone. Simultaneously, a high level of expression of glial fibrillary acidic protein and a low level of expression of neuron-specific enolase were visible in BrdU-labeled bone marrow mesenchymal stem cells. These findings suggest that transplantation of a composite of bone marrow mesenchymal stem cells and a chitosan-collagen scaffold has a neuroprotective effect following ischemic stroke.

  7. Localised controlled release of simvastatin from porous chitosan-gelatin scaffolds engrafted with simvastatin loaded PLGA-microparticles for bone tissue engineering application.

    PubMed

    Gentile, Piergiorgio; Nandagiri, Vijay Kumar; Daly, Jacqueline; Chiono, Valeria; Mattu, Clara; Tonda-Turo, Chiara; Ciardelli, Gianluca; Ramtoola, Zebunnissa

    2016-02-01

    Localised controlled release of simvastatin from porous freeze-dried chitosan-gelatin (CH-G) scaffolds was investigated by incorporating simvastatin loaded poly-(dl-lactide-co-glycolide) acid (PLGA) microparticles (MSIMs) into the scaffolds. MSIMs at 10% w/w simvastatin loading were prepared using a single emulsion-solvent evaporation method. The MSIM optimal amount to be incorporated into the scaffolds was selected by analysing the effect of embedding increasing amounts of blank PLGA microparticles (BL-MPs) on the scaffold physical properties and on the in vitro cell viability using a clonal human osteoblastic cell line (hFOB). Increasing the BL-MP content from 0% to 33.3% w/w showed a significant decrease in swelling degree (from 1245±56% to 570±35%). Scaffold pore size and distribution changed significantly as a function of BL-MP loading. Compressive modulus of scaffolds increased with increasing BL-MP amount up to 16.6% w/w (23.0±1.0kPa). No significant difference in cell viability was observed with increasing BL-MP loading. Based on these results, a content of 16.6% w/w MSIM particles was incorporated successfully in CH-G scaffolds, showing a controlled localised release of simvastatin able to influence the hFOB cell proliferation and the osteoblastic differentiation after 11days. PMID:26652371

  8. Relationship between micro-porosity, water permeability and mechanical behavior in scaffolds for cartilage engineering.

    PubMed

    Vikingsson, L; Claessens, B; Gómez-Tejedor, J A; Gallego Ferrer, G; Gómez Ribelles, J L

    2015-08-01

    In tissue engineering the design and optimization of biodegradable polymeric scaffolds with a 3D-structure is an important field. The porous scaffold provide the cells with an adequate biomechanical environment that allows mechanotransduction signals for cell differentiation and the scaffolds also protect the cells from initial compressive loading. The scaffold have interconnected macro-pores that host the cells and newly formed tissue, while the pore walls should be micro-porous to transport nutrients and waste products. Polycaprolactone (PCL) scaffolds with a double micro- and macro-pore architecture have been proposed for cartilage regeneration. This work explores the influence of the micro-porosity of the pore walls on water permeability and scaffold compliance. A Poly(Vinyl Alcohol) with tailored mechanical properties has been used to simulate the growing cartilage tissue inside the scaffold pores. Unconfined and confined compression tests were performed to characterize both the water permeability and the mechanical response of scaffolds with varying size of micro-porosity while volume fraction of the macro-pores remains constant. The stress relaxation tests show that the stress response of the scaffold/hydrogel construct is a synergic effect determined by the performance of the both components. This is interesting since it suggests that the in vivo outcome of the scaffold is not only dependent upon the material architecture but also the growing tissue inside the scaffold?s pores. On the other hand, confined compression results show that compliance of the scaffold is mainly controlled by the micro-porosity of the scaffold and less by hydrogel density in the scaffold pores. These conclusions bring together valuable information for customizing the optimal scaffold and to predict the in vivo mechanical behavior. PMID:25913609

  9. Osteogenesis and chondrogenesis of biomimetic integrated porous PVA/gel/V-n-HA/pa6 scaffolds and BMSCs construct in repair of articular osteochondral defect.

    PubMed

    Li, Xiang; Li, Yubao; Zuo, Yi; Qu, Dan; Liu, Yiming; Chen, Tao; Jiang, Nan; Li, Hui; Li, Jihua

    2015-10-01

    A novel bi-layered osteochondral scaffold, including of PVA/Gel/V layer for the cartilage and n-HA/PA6 layer for the subchondral bone, has been proposed to evaluate the potential of the engineered of osteochondral grafts in repairing articular osteochondral defects in rabbits. The two different layers of the scaffolds were seeded with allogenic bone marrow-derived stem cells (BMSCs), which were chondrogenically and osteogenically induced respectively. The critical-size osteochondral defects were created in the knees of adult rabbits. The defects were treated with cell-bi-layered constructs (Group A), bi-layered constructs (Group B) and untreated group C as control group. The adhesion, proliferation and differentiation of BMSCs were demonstrated by immunohistochemical staining and scanning electron microscopy (SEM) in vitro. Cell survival was tracked via fluorescent labeling in vivo. Overall, the porous PVA/Gel/V-n-HA/PA6 scaffold was compatible and had no negative effects on the BMSCs in vitro culture. The cell-bi-layered scaffolds showed superior repair results as compared to the control group using gross examination and histological assessment. With BMSCs implantation, the two different layers of the composite biomimetic scaffolds provided a suitable environment for cells to form respective tissue. Simultaneously, the RT-PCR results confirmed the expression of specific extracellular matrix (ECM) markers for cartilaginous or osteoid tissue. This investigation showed that the porous PVA/Gel/V-n-HA/PA6 scaffold is a potential matrix for treatment of osteochondral defects, and the method of using chondrogenically and osteogenically differentiated BMSCs as seed cells on each layer might be a promising strategy in repair of articular osteochondral defect due to enhanced chondrogenesis and osteogenesis. PMID:25772000

  10. Production and in vitro characterization of 3D porous scaffolds made of magnesium carbonate apatite (MCA)/anionic collagen using a biomimetic approach.

    PubMed

    Sader, Marcia S; Martins, Virginia C A; Gomez, Santiago; LeGeros, Racquel Z; Soares, Gloria A

    2013-10-01

    3D porous scaffolds are relevant biomaterials to bone engineering as they can be used as templates to tissue reconstruction. The aim of the present study was to produce and characterize in vitro 3D magnesium-carbonate apatite/collagen (MCA/col) scaffolds. They were prepared by using biomimetic approach, followed by cross-linking with 0.25% glutaraldehyde solution (GA) and liofilization. Results obtained with Fourier-transform infrared spectroscopy (FT-IR) confirmed the type-B carbonate substitution, while by X-ray diffraction (XRD), a crystallite size of ~10nm was obtained. Optical and electron microscopy showed that the cylindrical samples exhibited an open-porous morphology, with apatite nanocrystals precipitated on collagen fibrils. The cross-linked 3D scaffolds showed integrity when immersed in culture medium up to 14 days. Also, the immersion of such samples into an acid buffer solution, to mimic the osteoclastic resorption environment, promotes the release of important ions for bone repair, such as calcium, phosphorus and magnesium. Bone cells (SaOs2) adhered, and proliferated on the 3D composite scaffolds, showing that synthesis and the cross-linking processes did not induce cytotoxicity. PMID:23910332

  11. Scaffold development using selective laser sintering of polyetheretherketone-hydroxyapatite biocomposite blends.

    PubMed

    Tan, K H; Chua, C K; Leong, K F; Cheah, C M; Cheang, P; Abu Bakar, M S; Cha, S W

    2003-08-01

    In tissue engineering (TE), temporary three-dimensional scaffolds are essential to guide cell proliferation and to maintain native phenotypes in regenerating biologic tissues or organs. To create the scaffolds, rapid prototyping (RP) techniques are emerging as fabrication techniques of choice as they are capable of overcoming many of the limitations encountered with conventional manual-based fabrication processes. In this research, RP fabrication of solvent free porous polymeric and composite scaffolds was investigated. Biomaterials such as polyetheretherketone (PEEK) and hydroxyapatite (HA) were experimentally processed on a commercial selective laser sintering (SLS) RP system. The SLS technique is highly advantageous as it provides good user control over the microstructures of created scaffolds by adjusting the SLS process parameters. Different weight percentage (wt%) compositions of physically mixed PEEK/HA powder blends were sintered to assess their suitability for SLS processing. Microstructural assessments of the scaffolds were conducted using electron microscopy. The results ascertained the potential of SLS-fabricated TE scaffolds. PMID:12895584

  12. Study of the effect of external heating and internal temperature build-up during polymerization on the morphology of porous polymethacrylate adsorbent

    NASA Astrophysics Data System (ADS)

    Wei, Chan Yi; Ongkudon, Clarence M.; Kansil, Tamar

    2015-07-01

    Modern day synthesis protocols of methacrylate monolithic polymer adsorbent are based on existing polymerization blueprint without a thorough understanding of the dynamics of pore structure and formation. This has resulted in unproductiveness of polymer adsorbent consequently affecting purity and recovery of final product, productivity, retention time and cost effectiveness of the whole process. The problems magnified in monolith scaling-up where internal heat buildup resulting from external heating and high exothermic polymerization reaction was reflected in cracking of the adsorbent. We believe that through careful and precise control of the polymerization kinetics and parameters, it is possible to prepare macroporous methacrylate monolithic adsorbents with controlled pore structures despite being carried out in an unstirred mould. This research involved the study of the effect of scaling-up on pore morphology of monolith, in other words, porous polymethacrylate adsorbents that were prepared via bulk free radical polymerization process by imaging the porous morphology of polymethacrylate with scanning electron microscope.

  13. Biohybrid Fibro-Porous Vascular Scaffolds: Effect of Crosslinking on Properties

    PubMed Central

    Nozik, Danna; Patel, Harsh; Singh, Raj K.; Vohra, Yogesh K.

    2015-01-01

    Tubular grafts were fabricated from blends of polycaprolactone (PCL) and poly(glycolide -co-caprolactone) (PGC) polymers and coated with an extracellular matrix containing collagens, laminin, and proteoglycans, but not growth factors (HuBiogel™). Multifunctional scaffolds from polymer blends and membrane proteins provide the necessary biomechanics and biological functions for tissue regeneration. Two crosslinking agents, a natural crosslinker namely genipin (Gp) and a carbodiimide reagent namely 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), were used for further stabilizing the protein matrix and the effect of crosslinking was evaluated for structural, morphological, mechanical properties using SEM, DSC and DMA. SEM images and fiber diameter distribution showed fiber-size between 0.2 µm to 1 µm with the majority of fiber diameters being under 500 nm, indicating upper range of protein fiber-sizes (for example, collagen fibers in extracellular matrix are in 50 to 500 nm diameter range). HB coating did not affect the mechanical properties, but increased its hydrophilicity of the graft. Overall data showed that PCL/PGC blends with 3:1 mass ratio exhibited mechanical properties comparable to those of human native arteries (tensile strength of 1–2 MPa and Young’s modulus of <10 MPa). Additionally, the effect of crosslinking on coating stability was investigated to assure the retention of proteins on scaffold for effective cell-matrix interactions. PMID:26082566

  14. Challenges for Nerve Repair Using Chitosan-Siloxane Hybrid Porous Scaffolds

    PubMed Central

    Shirosaki, Yuki; Hayakawa, Satoshi; Osaka, Akiyoshi; Lopes, Maria A.; Santos, José D.; Geuna, Stefano; Mauricio, Ana C.

    2014-01-01

    The treatment of peripheral nerve injuries remains one of the greatest challenges of neurosurgery, as functional recover is rarely satisfactory in these patients. Recently, biodegradable nerve guides have shown great potential for enhancing nerve regeneration. A major advantage of these nerve guides is that no foreign material remains after the device has fulfilled its task, which spares a second surgical intervention. Recently, we studied peripheral nerve regeneration using chitosan-?-glycidoxypropyltrimethoxysilane (chitosan-GPTMS) porous hybrid membranes. In our studies, these porous membranes significantly improved nerve fiber regeneration and functional recovery in rat models of axonotmetic and neurotmetic sciatic nerve injuries. In particular, the number of regenerated myelinated nerve fibers and myelin thickness were significantly higher in rat treated with chitosan porous hybrid membranes, whether or not they were used in combination with mesenchymal stem cells isolated from the Wharton's jelly of the umbilical cord. In this review, we describe our findings on the use of chitosan-GPTMS hybrids for nerve regeneration. PMID:25054129

  15. A new method for the preparation of polymeric porous layer open tubular columns for GC application

    NASA Technical Reports Server (NTRS)

    Shen, T. C.; Wang, M. L.

    1995-01-01

    A new method to prepare polymeric PLOT columns by using in situ polymerization technology is described. The method involves a straightforward in situ polymerization of the monomer. The polymer produced is directly coated on the metal tubing. This eliminates many of the steps needed in conventional polymeric PLOT column preparation. Our method is easy to operate and produces very reproducible columns, as shown previously (T. C. Shen. J. Chromatogr. Sci. 30, 239, 1992). The effects of solvents, tubing pretreatments, initiators and reaction temperatures in the preparation of PLOT columns are studied. Several columns have been developed to separate (1) highly polar compounds, such as water and ammonia or water and HCN, and (2) hydrocarbons and inert gases. A recent improvement has allowed us to produce bonded polymeric PLOT columns. These were studied, and the results are included also.

  16. Multiple approaches to predicting oxygen and glucose consumptions by HepG2 cells on porous scaffolds in an axial-flow bioreactor.

    PubMed

    Podichetty, Jagdeep T; Bhaskar, Prasana R; Singarapu, Kumar; Madihally, Sundararajan V

    2015-02-01

    In this study, the distribution of oxygen and glucose was evaluated along with consumption by hepatocytes using three different approaches. The methods include (i) Computational Fluid Dynamics (CFD) simulation, (ii) residence time distribution (RTD) analysis using a step-input coupled with segregation model or dispersion model, and (iii) experimentally determined consumption by HepG2 cells in an open-loop. Chitosan-gelatin (CG) scaffolds prepared by freeze-drying and polycaprolactone (PCL) scaffolds prepared by salt leaching technique were utilized for RTD analyses. The scaffold characteristics were used in CFD simulations i.e. Brinkman's equation for flow through porous medium, structural mechanics for fluid induced scaffold deformation, and advection-diffusion equation coupled with Michaelis-Menten rate equations for nutrient consumption. With the assumption that each hepatocyte behaves like a micro-batch reactor within the scaffold, segregation model was combined with RTD to determine exit concentration. A flow rate of 1?mL/min was used in the bioreactor seeded with 0.6?×?10(6) HepG2 cells/cm(3) on CG scaffolds and oxygen consumption was measured using two flow-through electrodes located at the inlet and outlet. Glucose in the spent growth medium was also analyzed. RTD results showed distribution of nutrients to depend on the surface characteristics of scaffolds. Comparisons of outlet oxygen concentrations between the simulation results, and experimental results showed good agreement with the dispersion model. Outlet oxygen concentrations from segregation model predictions were lower. Doubling the cell density showed a need for increasing the flow rate in CFD simulations. This integrated approach provide a useful strategy in designing bioreactors and monitoring tissue regeneration. PMID:25116006

  17. Porous poly(alpha-hydroxyacid)/Bioglass composite scaffolds for bone tissue engineering. I: Preparation and in vitro characterisation.

    PubMed

    Maquet, V; Boccaccini, A R; Pravata, L; Notingher, I; Jérôme, R

    2004-08-01

    Highly porous composites scaffolds of poly-D,L-lactide (PDLLA) and poly(lactide-co-glycolide) (PLGA) containing different amounts (10, 25 and 50 wt%) of bioactive glass (45S5 Bioglass)were prepared by thermally induced solid-liquid phase separation (TIPS) and subsequent solvent sublimation. The addition of increasing amounts of Bioglass into the polymer foams decreased the pore volume. Conversely, the mechanical properties of the polymer materials were improved. The composites were incubated in phosphate buffer saline at 37 degrees C to study the in vitro degradation of the polymer by measurement of water absorption, weight loss as well as changes in the average molecular weight of the polymer and in the pH of the incubation medium as a function of the incubation time. The addition of Bioglass to polymer foams increased the water absorption and weight loss compared to neat polymer foams. However, the polymer molecular weight, determined by size exclusion chromatography, was found to decrease more rapidly and to a larger extent in absence of Bioglass. The presence of the bioactive filler was therefore found to delay the degradation rate of the polymer as compared to the neat polymer foams. Formation of hydroxyapatite on the surface of composites, as an indication of their bioactivity, was recorded by EDXA, X-ray diffractometry and confirmed by Raman spectroscopy. PMID:15046908

  18. Computer-Aided Process Planning for the Layered Fabrication of Porous Scaffold Matrices

    NASA Astrophysics Data System (ADS)

    Starly, Binil

    Rapid Prototyping (RP) technology promises to have a tremendous impact on the design and fabrication of porous tissue replacement structures for applications in tissue engineering and regenerative medicine. The layer-by-layer fabrication technology enables the design of patient-specific medical implants and complex structures for diseased tissue replacement strategies. Combined with advancements in imaging modalities and bio-modeling software, physicians can engage themselves in advanced solutions for craniofacial and mandibular reconstruction. For example, prior to the advancement of RP technologies, solid titanium parts used as implants for mandibular reconstruction were fashioned out of molding or CNC-based machining processes (Fig. 3.1). Titanium implants built using this process are often heavy, leading to increased patient discomfort. In addition, the Young's modulus of titanium is almost five times that of healthy cortical bone resulting in stress shielding effects [1,2]. With the advent of CAD/CAM-based tools, the virtual reconstruction of the implants has resulted in significant design improvements. The new generation of implants can be porous, enabling the in-growth of healthy bone tissue for additional implant fixation and stabilization. Newer implants would conform to the external shape of the defect site that is intended to be filled in. More importantly, the effective elastic modulus of the implant can be designed to match that of surrounding tissue. Ideally, the weight of the implant can be designed to equal the weight of the tissue that is being replaced resulting in increased patient comfort. Currently, such porous structures for reconstruction can only be fabricated using RP-based metal fabrication technologies such as Electron Beam Melting (EBM), Selective Laser Sintering (SLS®), and 3D™ Printing processes.

  19. A mathematical model and computational framework for three-dimensional chondrocyte cell growth in a porous tissue scaffold placed inside a bi-directional flow perfusion bioreactor.

    PubMed

    Shakhawath Hossain, Md; Bergstrom, D J; Chen, X B

    2015-12-01

    The in vitro chondrocyte cell culture for cartilage tissue regeneration in a perfusion bioreactor is a complex process. Mathematical modeling and computational simulation can provide important insights into the culture process, which would be helpful for selecting culture conditions to improve the quality of the developed tissue constructs. However, simulation of the cell culture process is a challenging task due to the complicated interaction between the cells and local fluid flow and nutrient transport inside the complex porous scaffolds. In this study, a mathematical model and computational framework has been developed to simulate the three-dimensional (3D) cell growth in a porous scaffold placed inside a bi-directional flow perfusion bioreactor. The model was developed by taking into account the two-way coupling between the cell growth and local flow field and associated glucose concentration, and then used to perform a resolved-scale simulation based on the lattice Boltzmann method (LBM). The simulation predicts the local shear stress, glucose concentration, and 3D cell growth inside the porous scaffold for a period of 30 days of cell culture. The predicted cell growth rate was in good overall agreement with the experimental results available in the literature. This study demonstrates that the bi-directional flow perfusion culture system can enhance the homogeneity of the cell growth inside the scaffold. The model and computational framework developed is capable of providing significant insight into the culture process, thus providing a powerful tool for the design and optimization of the cell culture process. Biotechnol. Bioeng. 2015;112: 2601-2610. © 2015 Wiley Periodicals, Inc. PMID:26061385

  20. Free-Form-Fabricated Commercially Pure Ti and Ti6Al4V Porous Scaffolds Support the Growth of Human Embryonic Stem Cell-Derived Mesodermal Progenitors

    PubMed Central

    de Peppo, G. M.; Palmquist, A.; Borchardt, P.; Lennerås, M.; Hyllner, J.; Snis, A.; Lausmaa, J.; Thomsen, P.; Karlsson, C.

    2012-01-01

    Commercially-pure titanium (cp-Ti) and the titanium-aluminum-vanadium alloy (Ti6Al4V) are widely used as reconstructive implants for skeletal engineering applications, due to their good mechanical properties, biocompatibility and ability to integrate with the surrounding bone. Electron beam melting technology (EBM) allows the fabrication of customized implants with tailored mechanical properties and high potential in the clinical practice. In order to augment the interaction with the biological tissue, stem cells have recently been combined with metallic scaffolds for skeletal engineering applications. We previously demonstrated that human embryonic stem cell-derived mesodermal progenitors (hES-MPs) hold a great potential to provide a homogeneous and unlimited supply of cells for bone engineering applications. This study demonstrates the effect of EBM-fabricated cp-Ti and Ti6Al4V porous scaffolds on hES-MPs behavior, in terms of cell attachment, growth and osteogenic differentiation. Displaying different chemical composition but similar surface properties, EBM-fabricated cp-Ti and Ti6Al4V scaffolds supported cell attachment and growth, and did not seem to alter the expression of genes involved in osteogenic differentiation and affect the alkaline phosphatase activity. In conclusion, interfacing hES-MPs to EBM-fabricated scaffolds may represent an interesting strategy for design of third-generation biomaterials, with the potential to promote implant integration in clinical conditions characterized by poor bone quality. PMID:22262956

  1. A multistep procedure to prepare pre-vascularized cardiac tissue constructs using adult stem sells, dynamic cell cultures, and porous scaffolds

    PubMed Central

    Pagliari, Stefania; Tirella, Annalisa; Ahluwalia, Arti; Duim, Sjoerd; Goumans, Marie-Josè; Aoyagi, Takao; Forte, Giancarlo

    2014-01-01

    The vascularization of tissue engineered products represents a key issue in regenerative medicine which needs to be addressed before the translation of these protocols to the bedside can be foreseen. Here we propose a multistep procedure to prepare pre-vascularized three-dimensional (3D) cardiac bio-substitutes using dynamic cell cultures and highly porous biocompatible gelatin scaffolds. The strategy adopted exploits the peculiar differentiation potential of two distinct subsets of adult stem cells to obtain human vascularized 3D cardiac tissues. In the first step of the procedure, human mesenchymal stem cells (hMSCs) are seeded onto gelatin scaffolds to provide interconnected vessel-like structures, while human cardiomyocyte progenitor cells (hCMPCs) are stimulated in vitro to obtain their commitment toward the cardiac phenotype. The use of a modular bioreactor allows the perfusion of the whole scaffold, providing superior performance in terms of cardiac tissue maturation and cell survival. Both the cell culture on natural-derived polymers and the continuous medium perfusion of the scaffold led to the formation of a densely packaged proto-tissue composed of vascular-like and cardiac-like cells, which might complete maturation process and interconnect with native tissue upon in vivo implantation. In conclusion, the data obtained through the approach here proposed highlight the importance to provide stem cells with complementary signals in vitro able to resemble the complexity of cardiac microenvironment. PMID:24917827

  2. Free-form-fabricated commercially pure Ti and Ti6Al4V porous scaffolds support the growth of human embryonic stem cell-derived mesodermal progenitors.

    PubMed

    de Peppo, G M; Palmquist, A; Borchardt, P; Lennerås, M; Hyllner, J; Snis, A; Lausmaa, J; Thomsen, P; Karlsson, C

    2012-01-01

    Commercially-pure titanium (cp-Ti) and the titanium-aluminum-vanadium alloy (Ti6Al4V) are widely used as reconstructive implants for skeletal engineering applications, due to their good mechanical properties, biocompatibility and ability to integrate with the surrounding bone. Electron beam melting technology (EBM) allows the fabrication of customized implants with tailored mechanical properties and high potential in the clinical practice. In order to augment the interaction with the biological tissue, stem cells have recently been combined with metallic scaffolds for skeletal engineering applications. We previously demonstrated that human embryonic stem cell-derived mesodermal progenitors (hES-MPs) hold a great potential to provide a homogeneous and unlimited supply of cells for bone engineering applications. This study demonstrates the effect of EBM-fabricated cp-Ti and Ti6Al4V porous scaffolds on hES-MPs behavior, in terms of cell attachment, growth and osteogenic differentiation. Displaying different chemical composition but similar surface properties, EBM-fabricated cp-Ti and Ti6Al4V scaffolds supported cell attachment and growth, and did not seem to alter the expression of genes involved in osteogenic differentiation and affect the alkaline phosphatase activity. In conclusion, interfacing hES-MPs to EBM-fabricated scaffolds may represent an interesting strategy for design of third-generation biomaterials, with the potential to promote implant integration in clinical conditions characterized by poor bone quality. PMID:22262956

  3. In vivo vascularization of anisotropic channeled porous polylactide-based capsules for islet transplantation: the effects of scaffold architecture and implantation site.

    PubMed

    Kasoju, N; Kubies, D; Fábryová, E; K?íž, J; Kumorek, M M; Sticová, E; Rypá?ek, F

    2015-01-01

    The replacement of pancreatic islets for the possible treatment of type 1 diabetes is limited by the extremely high oxygen demand of the islets. To this end, here we hypothesize to create a novel extra-hepatic highly-vascularized bioartificial cavity using a porous scaffold as a template and using the host body as a living bioreactor for subsequent islet transplantation. Polylactide-based capsular-shaped anisotropic channeled porous scaffolds were prepared by following the unidirectional thermally-induced phase separation technique, and were implanted under the skin and in the greater omentum of Brown Norway rats. Polyamide mesh-based isotropic regular porous capsules were used as the controls. After 4weeks, the implants were excised and analyzed by histology. The hematoxylin and eosin, as well as Masson's trichrome staining, revealed a) low or no infiltration of giant inflammatory cells in the implant, b) minor but insignificant fibrosis around the implant, c) guided infiltration of host cells in the test capsule in contrast to random cell infiltration in the control capsule, and d) relatively superior cell infiltration in the capsules implanted in the greater omentum than in the capsules implanted under the skin. Furthermore, the anti-CD31 immunohistochemistry staining revealed numerous vessels at the implant site, but mostly on the external surface of the capsules. Taken together, the current study, the first of its kind, is a significant step-forward towards engineering a bioartificial microenvironment for the transplantation of islets. PMID:26447597

  4. Effect of different hydroxyapatite incorporation methods on the structural and biological properties of porous collagen scaffolds for bone repair.

    PubMed

    Ryan, Alan J; Gleeson, John P; Matsiko, Amos; Thompson, Emmet M; O'Brien, Fergal J

    2014-11-20

    Scaffolds which aim to provide an optimised environment to regenerate bone tissue require a balance between mechanical properties and architecture known to be conducive to enable tissue regeneration, such as a high porosity and a suitable pore size. Using freeze-dried collagen-based scaffolds as an analogue of native ECM, we sought to improve the mechanical properties by incorporating hydroxyapatite (HA) in different ways while maintaining a pore architecture sufficient to allow cell infiltration, vascularisation and effective bone regeneration. Specifically we sought to elucidate the effect of different hydroxyapatite incorporation methods on the mechanical, morphological, and cellular response of the resultant collagen-HA scaffolds. The results demonstrated that incorporating either micron-sized (CHA scaffolds) or nano-sized HA particles (CnHA scaffolds) prior to freeze-drying resulted in moderate increases in stiffness (2.2-fold and 6.2-fold, respectively, vs. collagen-glycosaminoglycan scaffolds, P < 0.05, a scaffold known to support osteogenesis), while enabling good cell attachment, and moderate mesenchymal stem cell (MSC)-mediated calcium production after 28 days' culture (2.1-fold, P < 0.05, and 1.3-fold, respectively, vs. CG scaffolds). However, coating of collagen scaffolds with a hydroxyapatite precipitate after freeze-drying (CpHA scaffolds) has been shown to be a highly effective method to increase the compressive modulus (26-fold vs. CG controls, P < 0.001) of scaffolds while maintaining a high porosity (~ 98%). The coating of the ligand-dense collagen structure results in a lower cell attachment level (P < 0.05), although it supported greater cell-mediated calcium production (P < 0.0001) compared with other scaffold variants after 28 days' culture. The comparatively good mechanical properties of these high porosity scaffolds is obtained partially through highly crosslinking the scaffolds with both a physical (DHT) and chemical (EDAC) crosslinking treatment. Control of scaffold microstructure was examined via alterations in freezing temperature. It was found that the addition of HA prior to freeze-drying generally reduced the pore size and so the CpHA scaffold fabrication method offered increased control over the resulting scaffolds microstructure. These findings will help guide future design considerations for composite biomaterials and demonstrate that the method of HA incorporation can have profound effects on the resulting scaffold structural and biological response. PMID:25409684

  5. Vapor deposition polymerization of aniline on 3D hierarchical porous carbon with enhanced cycling stability as supercapacitor electrode

    NASA Astrophysics Data System (ADS)

    Zhao, Yufeng; Zhang, Zhi; Ren, Yuqin; Ran, Wei; Chen, Xinqi; Wu, Jinsong; Gao, Faming

    2015-07-01

    In this work, a polyaniline coated hierarchical porous carbon (HPC) composite (PANI@HPC) is developed using a vapor deposition polymerization technique. The as synthesized composite is applied as the supercapacitor electrode material, and presents a high specific capacitance of 531 F g-1 at current density of 0.5 A g-1 and superior cycling stability of 96.1% (after 10,000 charge-discharge cycles at current density of 10 A g-1). This can be attributed to the maximized synergistic effect of PANI and HPC. Furthermore, an aqueous symmetric supercapacitor device based on PANI@HPC is fabricated, demonstrating a high specific energy of 17.3 Wh kg-1.

  6. Synthesis of porous acrylonitrile/methyl acrylate copolymer beads by suspended emulsion polymerization and their adsorption properties after amidoximation.

    PubMed

    Liu, Xin; Chen, Hou; Wang, Chunhua; Qu, Rongjun; Ji, Chunnuan; Sun, Changmei; Zhang, Ying

    2010-03-15

    Porous acrylonitrile (AN)/methyl acrylate (MA) copolymer beads were prepared by suspended emulsion polymerization. The cyano groups in AN/MA copolymer beads were converted to amidoxime (AO) groups by reaction with hydroxylamine hydrochloride (NH(2)OH.HCl) to remove metal ions in aqueous solution. The untreated AN/MA and amidoximated AN/MA (AO AN/MA) copolymer beads were characterized by FTIR spectroscopy, SEM, and porous structural analysis. Both mesopores and macropores were presented in AN/MA and AO AN/MA copolymer beads. Qualitative experiments of adsorption were conducted to evaluate modified and unmodified resins on fixing Hg(2+), Ag(+), Cu(2+), Fe(3+) and Pb(2+) from aqueous solution using batch extractions. It was found that AO AN/MA copolymer beads have excellent adsorption capacities for Hg(2+), Ag(+) and Cu(2+), especially for Hg(2+), and it have good selectivity for Hg(2+). The equilibrium was established in 10h through adsorption kinetics study. The Langmuir model was much better than the Freundlich model to describe the isothermal process. PMID:19939561

  7. A one-step method to fabricate PLLA scaffolds with deposition of bioactive hydroxyapatite and collagen using ice-based microporogens

    PubMed Central

    Li, Jiashen; Chen, Yun; Mak, Arthur F.T.; Tuan, Rocky S.; Li, Lin; Li, Yi

    2010-01-01

    Porous poly(L-lactic acid) (PLLA) scaffolds with bioactive coatings were prepared by a novel one-step method. In this process, ice-based microporogens containing bioactive molecules, such as hydroxyapatite (HA) and collagen, served as both porogens to form the porous structure and vehicles to transfer the bioactive molecules to the inside of PLLA scaffolds in a single step. Based on scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis, the bioactive components were found to be transferred successfully from the porogens to PLLA scaffolds evenly. Osteoblast cells were used to evaluate the cellular behaviors of the composite scaffolds. After 8 days culturing, MTT assay and alkaline phosphatase (ALP) activity results suggested that HA/collagen could improve the interactions between osteoblast cells and the polymeric scaffold. PMID:20004261

  8. Extraction of naphthenic acid from kerosene using porous and nonporous polymeric membranes

    SciTech Connect

    Netke, S.A.; Pangarkar, V.G.

    1996-01-01

    A systematic study of membrane-assisted extraction of naphthenic acids from hydrocarbon fractions by aqueous caustic soda using both porous and nonporous membranes is reported. The effects of hydrodynamic factors, concentration of naphthenic acids and caustic soda, and temperature on the transmembrane flux are discerned. The film model is used to determine the intrinsic mass transfer characteristics of the membranes.

  9. Osteogenic differentiation of dura mater stem cells cultured in vitro on three-dimensional porous scaffolds of poly(?-caprolactone) fabricated via co-extrusion and gas foaming

    PubMed Central

    Aronin, C.E. Petrie; Cooper, J.A.; Sefcik, L.S.; Tholpady, S.S.; Ogle, R.C.; Botchwey, E.A.

    2008-01-01

    A novel scaffold fabrication method utilizing both polymer blend extrusion and gas foaming techniques to control pore size distribution is presented. Seventy five per cent of all pores produced using polymer blend extrusion alone were less than 50 ?m. Introducing a gas technique provided better control of pore size distribution, expanding the range from 0-50 to 0-350 ?m. Varying sintering time, annealing temperature and foaming pressure also helped reduced the percentage of pore sizes below 50 ?m. Scaffolds chosen for in vitro cellular studies had a pore size distribution of 0-300 ?m, average pore size 66 ± 17 ?m, 0.54 ± 0.02% porosity and 98% interconnectivity, measured by micro computed tomography (microCT) analysis. The ability of the scaffolds to support osteogenic differentiation and cranial defect repair was evaluated by static and dynamic (0.035 ± 0.006 m s-1 terminal velocity) cultivation with dura mater stem cells (DSCs). In vitro studies showed minimal increases in proliferation over 28 days in culture in osteogenic media. Alkaline phosphatase expression remained constant throughout the study. Moderate increases in matrix deposition, as assessed by histochemical staining and microCT analysis, occurred at later time points, days 21 and 28. Although constructs cultured dynamically showed greater mineralization than static conditions, these trends were not significant. It remains unclear whether bioreactor culture of DSCs is advantageous for bone tissue engineering applications. However, these studies show that polycaprolactone (PCL) scaffolds alone, without the addition of other co-polymers or ceramics, support long-term attachment and mineralization of DSCs throughout the entire porous scaffold. PMID:18434267

  10. Metal filled porous carbon

    SciTech Connect

    Gross, Adam F.; Vajo, John J.; Cumberland, Robert W.; Liu, Ping; Salguero, Tina T.

    2011-03-22

    A porous carbon scaffold with a surface and pores, the porous carbon scaffold containing a primary metal and a secondary metal, where the primary metal is a metal that does not wet the surface of the pores of the carbon scaffold but wets the surface of the secondary metal, and the secondary metal is interspersed between the surface of the pores of the carbon scaffold and the primary metal.

  11. Enhanced angiogenesis and osteogenesis in critical bone defects by the controlled release of BMP-2 and VEGF: implantation of electron beam melting-fabricated porous Ti6Al4V scaffolds incorporating growth factor-doped fibrin glue.

    PubMed

    Lv, Jia; Xiu, Peng; Tan, Jie; Jia, Zhaojun; Cai, Hong; Liu, Zhongjun

    2015-06-01

    Electron beam melting (EBM)-fabricated porous titanium implants possessing low elastic moduli and tailored structures are promising biomaterials for orthopedic applications. However, the bio-inert nature of porous titanium makes reinforcement with growth factors (GFs) a promising method to enhance implant in vivo performance. Bone-morphogenic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) are key factors of angiogenesis and osteogenesis. Therefore, the present study is aimed at evaluating EBM-fabricated porous titanium implants incorporating GF-doped fibrin glue (FG) as composite scaffolds providing GFs for improvement of angiogenesis and osteogenesis in rabbit femoral condyle defects. BMP-2 and VEGF were added into the constituent compounds of FG, and then this GF-doped FG was subsequently injected into the porous scaffolds. In five groups of implants, angiogenesis and osteogenesis were evaluated at 4?weeks post-implantation using Microfil perfusion and histological analysis: eTi (empty scaffolds), cTi (containing undoped FG), BMP/cTi (containing 50??g rhBMP-2), VEGF/cTi (containing 0.5??g VEGF) and Dual/cTi (containing 50??g rhBMP-2 and 0.5??g VEGF). The results demonstrate that these composite implants are biocompatible and provide the desired gradual release of the bioactive growth factors. Incorporation of GF delivery, whether a single factor or dual factors, significantly enhanced both angiogenesis and osteogenesis inside the porous scaffolds. However, the synergistic effect of the dual factors combination was observable on angiogenesis but absent on osteogenesis. In conclusion, fibrin glue is a biocompatible material that could be employed as a delivery vehicle in EBM-fabricated porous titanium for controlled release of BMP-2 and VEGF. Application of this method for loading a porous titanium scaffold to incorporate growth factors is a convenient and promising strategy for improving osteogenesis of critical-sized bone defects. PMID:26107105

  12. Bone Regeneration of Hydroxyapatite/Alumina Bilayered Scaffold with 3?mm Passage-Like Medullary Canal in Canine Tibia Model

    PubMed Central

    Kim, Jong Min; Son, Jun Sik; Kim, Gonhyung; Choi, Seok Hwa

    2015-01-01

    The aim of this study was to evaluate the bone regeneration of hydroxyapatite (HA)/alumina bilayered scaffold with a 3?mm passage-like medullary canal in a beagle tibia model. A porous HA/alumina scaffold was fabricated using a polymeric template-coating technique. HA/alumina scaffold dimensions were 10?mm in outer diameter, 20?mm in length, and with either a 3?mm passage or no passage. A 20?mm segmental defect was induced using an oscillating saw through the diaphysis of the beagle tibia. The defects of six beagles were filled with HA/alumina bilayered scaffolds with a 3?mm passage or without. The segmental defect was fixated using one bone plate and six screws. Bone regeneration within the HA/alumina scaffolds was observed at eight weeks after implantation. The evaluation of bone regeneration within the scaffolds after implantation in a beagle tibia was performed using radiography, computerized tomography (CT), micro-CT, and fluorescence microscopy. New bone successfully formed in the tibia defects treated with 3?mm passage HA/alumina scaffolds compared to without-passage HA/alumina scaffolds. It was concluded that the HA/alumina bilayered scaffold with 3?mm passage-like medullary canal was instrumental in inducing host-scaffold engraftment of the defect as well as distributing the newly formed bone throughout the scaffold at 8 weeks after implantation. PMID:25688353

  13. Bone regeneration of hydroxyapatite/alumina bilayered scaffold with 3?mm passage-like medullary canal in canine tibia model.

    PubMed

    Kim, Jong Min; Son, Jun Sik; Kang, Seong Soo; Kim, Gonhyung; Choi, Seok Hwa

    2015-01-01

    The aim of this study was to evaluate the bone regeneration of hydroxyapatite (HA)/alumina bilayered scaffold with a 3?mm passage-like medullary canal in a beagle tibia model. A porous HA/alumina scaffold was fabricated using a polymeric template-coating technique. HA/alumina scaffold dimensions were 10?mm in outer diameter, 20?mm in length, and with either a 3?mm passage or no passage. A 20?mm segmental defect was induced using an oscillating saw through the diaphysis of the beagle tibia. The defects of six beagles were filled with HA/alumina bilayered scaffolds with a 3?mm passage or without. The segmental defect was fixated using one bone plate and six screws. Bone regeneration within the HA/alumina scaffolds was observed at eight weeks after implantation. The evaluation of bone regeneration within the scaffolds after implantation in a beagle tibia was performed using radiography, computerized tomography (CT), micro-CT, and fluorescence microscopy. New bone successfully formed in the tibia defects treated with 3?mm passage HA/alumina scaffolds compared to without-passage HA/alumina scaffolds. It was concluded that the HA/alumina bilayered scaffold with 3?mm passage-like medullary canal was instrumental in inducing host-scaffold engraftment of the defect as well as distributing the newly formed bone throughout the scaffold at 8 weeks after implantation. PMID:25688353

  14. MicroRNA-26a-modified adipose-derived stem cells incorporated with a porous hydroxyapatite scaffold improve the repair of bone defects

    PubMed Central

    WANG, ZHENLIN; ZHANG, DAWEI; HU, ZHIQIANG; CHENG, JIWEI; ZHUO, CHUANMENG; FANG, XIANCONG; XING, YONGMING

    2015-01-01

    Tissue-engineered bone substitutes are frequently used to repair bone defects. Adipose-derived stem cells (ASCs) are a promising source of cells for repairing bone tissue, however, insufficient osteogenic potency remains the main obstacle for their application. The present study aimed to enhance the osteogenic potency of ASCs by transfection of microRNA (miR)-26a, a novel osteogenic and angiogenic promoting miRNA. An inverted fluorescence microscope was used to observe transfection efficiency, while a scanning electron microscope was used to detect morphological alterations. Cell proliferation was monitored continuously for 7 days using a Cell Counting kit-8 assay. Osteogenic differentiation was determined by reverse transcription quantitative polymerase chain reaction, alkaline phosphatase (ALP) staining, collagen secretion and extracellular matrix (ECM) mineralization. ASCs were incorporated with a porous hydroxyapatite (HA) scaffold to create a novel tissue-engineered bone substitute and inserted into the critical tibia defect of rats. New bone formation was evaluated by hematoxylin and eosin and Masson's trichrome staining. The results demonstrated that miR-26a was successfully delivered into the cytoplasm, while the morphology and proliferation of ASCs were not significantly altered. Osteogenic-associated genes were markedly upregulated and ALP production, collagen secretion and ECM mineralization were all increased following transfection of miR-26a. Histological evaluation demonstrated that the modified cells accompanied with a porous HA scaffold markedly promoted new bone formation within the defective area. In conclusion, miR-26a transfection significantly improved the osteogenic potency of ASCs suggesting that modified ASCs incorporated with a HA scaffold may be used as a potential bone substitute. PMID:25997460

  15. Active scaffolds for on-demand drug and cell delivery

    E-print Network

    Zhao, Xuanhe

    Porous biomaterials have been widely used as scaffolds in tissue engineering and cell-based therapies. The release of biological agents from conventional porous scaffolds is typically governed by molecular diffusion, ...

  16. Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds

    NASA Technical Reports Server (NTRS)

    Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

    2011-01-01

    A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

  17. Research of osteoblastic induced rat bone marrow mesenchymal stem cells cultured on ?-TCP/PLLA porous scaffold

    PubMed Central

    Yang, Yi; Wu, Jiang; Jin, Gele; Li, Liang; Li, Zhongwei; Li, Cao

    2015-01-01

    Background: Ceramic and polymer composite scaffolds are widely used in tissue engineering for bone tissue regeneration. Composite of ?-tricalcium phosphate (?-TCP) and poly L-lactic acid (PLLA), due to its biocompatibility and biodegradability, is widely used in bioengineering. However, optimal ratio, porosity and pore size of this kind of scaffolds were not very clear yet. Materials and methods: We cultured osteoblastic induced rMSCs on ?-TCP/PLLA scaffolds to investigate the optimum construction, which owned better properties for supporting cells growth, proliferation and differentiation. A total of 24 mice were divided into three groups: rMSCs + ?-TCP/PLLA, osteoblastic rMSCs + ?-TCP/PLLA and ?-TCP/PLLA without cells. 8 rude mice were implanted with rMSCs + ?-TCP/PLLA in the left thighs and ?-TCP/PLLA without cells in the right thighs. 8 rude mice were implanted with osteoblastic rMSCs + ?-TCP/PLLA in the left thighs and the same treatments in the right thighs as the above. After 8 and 12 weeks, the mice were sacrificed and implants with the surrounding tissues were harvested together. Paraffin sections were got and HE stain and Masson-Goldner stain were employed to observe the ectopic bone formation. Results: The scaffolds of ?-TCP/PLLA = 2:1 significantly increased osteocalcin production of the cells. In addition, scaffolds with NaCl = 70 wt%, pore size 200~450 ?m showed better compatibility to these seeding cells. A significantly larger area of bone formation in the osteoblastic rMSCs and ?-TCP/PLLA composite than that in rMSCs/scaffold and in the scaffold without cells in vivo. Conclusion: compounds of osteoblastic induced rMSCs and the scaffold with ?-TCP/PLLA = 2:1, NaCl = 70 wt%, pore size = 200-450 ?m had good properties as a kind of bone substitute. PMID:26064209

  18. Scaffold: a novel carrier for cell and drug delivery.

    PubMed

    Garg, Tarun; Singh, Onkar; Arora, Saahil; Murthy, R

    2012-01-01

    Scaffolds are implants or injects, which are used to deliver cells, drugs, and genes into the body. Different forms of polymeric scaffolds for cell/drug delivery are available: (1) a typical three-dimensional porous matrix, (2) a nanofibrous matrix, (3) a thermosensitive sol-gel transition hydrogel, and (4) a porous microsphere. A scaffold provides a suitable substrate for cell attachment, cell proliferation, differentiated function, and cell migration. Scaffold matrices can be used to achieve drug delivery with high loading and efficiency to specific sites. Biomaterials used for fabrication of scaffold may be natural polymers such as alginate, proteins, collagens, gelatin, fibrins, and albumin, or synthetic polymers such as polyvinyl alcohol and polyglycolide. Bioceramics such as hydroxyapatites and tricalcium phosphates also are used. Techniques used for fabrication of a scaffold include particulate leaching, freeze-drying, supercritical fluid technology, thermally induced phase separation, rapid prototyping, powder compaction, sol-gel, and melt moulding. These techniques allow the preparation of porous structures with regular porosity. Scaffold are used successfully in various fields of tissue engineering such as bone formation, periodontal regeneration, repair of nasal and auricular malformations, cartilage development, as artificial corneas, as heart valves, in tendon repair ,in ligament replacement, and in tumors. They also are used in joint pain inflammation, diabetes, heart disease, osteochondrogenesis, and wound dressings. Their application of late has extended to delivery of drugs and genetic materials, including plasmid DNA, at a controlled rate over a long period of time. In addition, the incorporation of drugs (i.e., inflammatory inhibitors and/or antibiotics) into scaffolds may be used to prevent infection after surgery and other disease for longer duration. Scaffold also can be used to provide adequate signals (e.g., through the use of adhesion peptides and growth factors) to the cells, to induce and maintain them in their desired differentiation stage, and to maintain their survival and growth. The present review gives a detailed account of the need for the development of scaffolds along with the materials used and techniques adopted to manufacture scaffolds for tissue engineering and for prolonged drug delivery. PMID:22356721

  19. Biomimetic nanoclay scaffolds for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Ambre, Avinash Harishchandra

    Tissue engineering offers a significant potential alternative to conventional methods for rectifying tissue defects by evoking natural regeneration process via interactions between cells and 3D porous scaffolds. Imparting adequate mechanical properties to biodegradable scaffolds for bone tissue engineering is an important challenge and extends from molecular to macroscale. This work focuses on the use of sodium montmorillonite (Na-MMT) to design polymer composite scaffolds having enhanced mechanical properties along with multiple interdependent properties. Materials design beginning at the molecular level was used in which Na-MMT clay was modified with three different unnatural amino acids and further characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD). Based on improved bicompatibility with human osteoblasts (bone cells) and intermediate increase in d-spacing of MMT clay (shown by XRD), 5-aminovaleric acid modified clay was further used to prepare biopolymer (chitosan-polygalacturonic acid complex) scaffolds. Osteoblast proliferation in biopolymer scaffolds containing 5-aminovaleric acid modified clay was similar to biopolymer scaffolds containing hydroxyapatite (HAP). A novel process based on biomineralization in bone was designed to prepare 5-aminovaleric acid modified clay capable of imparting multiple properties to the scaffolds. Bone-like apatite was mineralized in modified clay and a novel nanoclay-HAP hybrid (in situ HAPclay) was obtained. FTIR spectroscopy indicated a molecular level organic-inorganic association between the intercalated 5-aminovaleric acid and mineralized HAP. Osteoblasts formed clusters on biopolymer composite films prepared with different weight percent compositions of in situ HAPclay. Human MSCs formed mineralized nodules on composite films and mineralized extracellular matrix (ECM) in composite scaffolds without the use of osteogenic supplements. Polycaprolactone (PCL), a synthetic polymer, was used for preparing composites (films and scaffolds) containing in situ HAPclay. Composite films showed significantly improved nanomechanical properties. Human MSCs formed mineralized ECM on films in absence of osteogenic supplements and were able to infiltrate the scaffolds. Atomic force microscopy imaging of mineralized ECM formed on composite films showed similarities in dimensions, arrangement of collagen and apatite with their natural bone counterparts. This work indicates the potential of in situ HAPclay to impart polymeric scaffolds with osteoinductive, osteoconductive abilities and improve their mechanical properties besides emphasizing nanoclays as cell-instructive materials.

  20. Preparation of a porous conductive scaffold from aniline pentamer-modified polyurethane/PCL blend for cardiac tissue engineering.

    PubMed

    Baheiraei, Nafiseh; Yeganeh, Hamid; Ai, Jafar; Gharibi, Reza; Ebrahimi-Barough, Somayeh; Azami, Mahmoud; Vahdat, Sadaf; Baharvand, Hossein

    2015-10-01

    A novel biodegradable electroactive polyurethane containing aniline pentamer (AP) was blended with polycaprolactone (PCL). The prepared blend (PB) and PCL were further fabricated in to scaffolds using a mixture of poly(ethylene glycol) and salt particles in a double porogen particulate leaching and compression molding methodology. Scaffolds held open and interconnected pores having pore size ranging from several ?m to 150 µm. PB scaffolds had compression modulus and strength of 4.1 and 1.3 MPa, respectively. The conductivity of the scaffold was measured as 10(-5) ± 0.09 S .cm(-1) and preserved for at least 100 h post fabrication. Scaffolds supported neonatal cardiomyocytes adhesion and growth with PB showing more extensive effect on the expression of the cardiac genes involved in muscle contraction and relaxation (troponin-T) and cytoskeleton alignment (actinin-4). Our results highlight the potential of incorporation of AP as an electroactive moiety for induction of cardiomyocyte proliferation and repair of damaged heart tissue. PMID:25765879

  1. DBD atmospheric plasma-modified, electrospun, layer-by-layer polymeric scaffolds for L929 fibroblast cell cultivation.

    PubMed

    Surucu, Seda; Turkoglu Sasmazel, Hilal

    2016-02-01

    This paper reported a study related to atmospheric pressure dielectric barrier discharge (DBD) Ar + O2 and Ar + N2 plasma modifications to alter surface properties of 3D PCL/Chitosan/PCL layer-by-layer hybrid scaffolds and to improve mouse fibroblast (L929 ATCC CCL-1) cell attachment, proliferation, and growth. The scaffolds were fabricated using electrospinning technique and each layer was electrospun sequentially on top of the other. The surface modifications were performed with an atmospheric pressure DBD plasma under different gas flow rates (50, 60, 70, 80, 90, and 100 sccm) and for different modification times (0.5-7 min), and then the chemical and topographical characterizations of the modified samples were done by contact angle (CA) measurements, scanning electron microscopy (SEM), atomic force microscopy, and X-ray photoelectron spectroscopy. The samples modified with Ar + O2 plasma for 1 min under 70 cm(3)/min O2 flow rate (71.077° ± 3.578) showed a 18.83% decrease compare to unmodified samples' CA value (84.463° ± 3.864). Comparing with unmodified samples, the average fiber diameter values for plasma-modified samples by Ar + O2 (1 min 70 sccm) and Ar + N2 (40 s 70 sccm) increased 40.756 and 54.295%, respectively. Additionally, the average inter-fiber pore size values exhibited decrease of 37.699 and 48.463% for the same Ar + O2 and Ar + N2 plasma-modified samples, respectively, compare to unmodified samples. Biocompatibility performance was determined with MTT assay, fluorescence, Giemsa, and confocal imaging as well as SEM. The results showed that Ar + O2-based plasma modification increased the hydrophilicity and oxygen functionality of the surface, thus affecting the cell viability and proliferation on/within scaffolds. PMID:26494511

  2. Tailoring the morphology of high molecular weight PLLA scaffolds through bioglass addition.

    PubMed

    Barroca, N; Daniel-da-Silva, A L; Vilarinho, P M; Fernandes, M H V

    2010-09-01

    Thermally induced phase separation (TIPS) has proven to be a suitable method for the preparation of porous structures for tissue engineering applications, and particular attention has been paid to increasing the pore size without the use of possible toxic surfactants. Within this context, an alternative method to control the porosity of polymeric scaffolds via the combination with a bioglass is proposed in this work. The addition of a bioactive glass from the 3CaO x P2O5-MgO-SiO2 system enables the porous structure of high molecular weight poly(l-lactic) acid (PLLA) scaffolds prepared by TIPS to be tailored. Bioglass acts as a nucleating catalyst agent of the PLLA matrix, promoting its crystallization, and the glass solubility controls the pore size. A significant increase in the pore size is observed as the bioglass content increases and scaffolds with large pore size (approximately 150 microm) can be prepared. In addition, the bioactive character of the scaffolds is proved by in vitro tests in synthetic plasma. The importance of this approach resides on the combination of the ability to tailor the porosity of polymeric scaffolds via the tunable solubility of bioglasses, without the use of toxic surfactants, leading to a composite structure with suitable properties for bone tissue engineering applications. PMID:20350622

  3. 3D polylactide-based scaffolds for studying human hepatocarcinoma processes in vitro

    NASA Astrophysics Data System (ADS)

    Scaffaro, Roberto; Lo Re, Giada; Rigogliuso, Salvatrice; Ghersi, Giulio

    2012-08-01

    We evaluated the combination of leaching techniques and melt blending of polymers and particles for the preparation of highly interconnected three-dimensional polymeric porous scaffolds for in vitro studies of human hepatocarcinoma processes. More specifically, sodium chloride and poly(ethylene glycol) (PEG) were used as water-soluble porogens to form porous and solvent-free poly(L,D-lactide) (PLA)-based scaffolds. Several characterization techniques, including porosimetry, image analysis and thermogravimetry, were combined to improve the reliability of measurements and mapping of the size, distribution and microarchitecture of pores. We also investigated the effect of processing, in PLA-based blends, on the simultaneous bulk/surface modifications and pore architectures in the scaffolds, and assessed the effects on human hepatocarcinoma viability and cell adhesion. The influence of PEG molecular weight on the scaffold morphology and cell viability and adhesion were also investigated. Morphological studies indicated that it was possible to obtain scaffolds with well-interconnected pores of assorted sizes. The analysis confirmed that SK-Hep1 cells adhered well to the polymeric support and emitted surface protrusions necessary to grow and differentiate three-dimensional systems. PEGs with higher molecular weight showed the best results in terms of cell adhesion and viability.

  4. Smart Porous Silicon Nanoparticles with Polymeric Coatings for Sequential Combination Therapy.

    PubMed

    Xu, Wujun; Thapa, Rinez; Liu, Dongfei; Nissinen, Tuomo; Granroth, Sari; Närvänen, Ale; Suvanto, Mika; Santos, Hélder A; Lehto, Vesa-Pekka

    2015-11-01

    In spite of the advances in drug delivery, the preparation of smart nanocomposites capable of precisely controlled release of multiple drugs for sequential combination therapy is still challenging. Here, a novel drug delivery nanocomposite was prepared by coating porous silicon (PSi) nanoparticles with poly(beta-amino ester) (PAE) and Pluronic F-127, respectively. Two anticancer drugs, doxorubicin (DOX) and paclitaxel (PTX), were separately loaded into the core of PSi and the shell of F127. The nanocomposite displayed enhanced colloidal stability and good cytocompatibility. Moreover, a spatiotemporal drug release was achieved for sequential combination therapy by precisely controlling the release kinetics of the two tested drugs. The release of PTX and DOX occurred in a time-staggered manner; PTX was released much faster and earlier than DOX at pH 7.0. The grafted PAE on the external surface of PSi acted as a pH-responsive nanovalve for the site-specific release of DOX. In vitro cytotoxicity tests demonstrated that the DOX and PTX coloaded nanoparticles exhibited a better synergistic effect than the free drugs in inducing cellular apoptosis. Therefore, the present study demonstrates a promising strategy to enhance the efficiency of combination cancer therapies by precisely controlling the release kinetics of different drugs. PMID:26390039

  5. Fast and continuous preparation of high polymerization degree cellulose nanofibrils and their three-dimensional macroporous scaffold fabrication

    NASA Astrophysics Data System (ADS)

    Song, Jiankang; Tang, Aimin; Liu, Tingting; Wang, Jufang

    2013-02-01

    C6-carboxy-cellulose with a carboxylate content of 0.8 mmol g-1 was obtained by oxidation of once-dried cellulose, using the 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)/NaClO/NaClO2 system at pH 6.8 and 60 °C for 16 h. This method, with the addition of reagents in the order TEMPO, NaClO and NaClO2, was 38 h faster than a previously published method. Individualized cellulose nanofibrils with a width of 3-5 nm and a length of several hundred nanometers were prepared by homogenizing the C6-carboxy-cellulose-water suspension. Macroporous cellulose nanofibril/poly(vinyl alcohol) scaffolds with interconnected large pores of 20-100 ?m diameter and small pores of 2-10 ?m diameter were fabricated. The cellulose nanofilaments formed nanofibrous structures on the surface of the PVA wall, which was similar to that of the collagen skeleton of the extracellular matrix. NIH/3T3 cells were cultured in the scaffolds for 4 weeks, SEM observation showed that the cells were anchored and clustered on the cellulose nanofilaments, forming spherical colonies. The extracellular matrix (ECM) was filled with mineralized particles.

  6. Laser printing of cells into 3D scaffolds.

    PubMed

    Ovsianikov, A; Gruene, M; Pflaum, M; Koch, L; Maiorana, F; Wilhelmi, M; Haverich, A; Chichkov, B

    2010-03-01

    One of the most promising approaches in tissue engineering is the application of 3D scaffolds, which provide cell support and guidance in the initial tissue formation stage. The porosity of the scaffold and internal pore organization influence cell migration and play a major role in its biodegradation dynamics, nutrient diffusion and mechanical stability. In order to control cell migration and cellular interactions within the scaffold, novel technologies capable of producing 3D structures in accordance with predefined design are required. The two-photon polymerization (2PP) technique, used in this report for the fabrication of scaffolds, allows the realization of arbitrary 3D structures with submicron spatial resolution. Highly porous 3D scaffolds, produced by 2PP of acrylated poly(ethylene glycol), are seeded with cells by means of laser-induced forward transfer (LIFT). In this laser printing approach, a propulsive force, resulting from laser-induced shock wave, is used to propel individual cells or cell groups from a donor substrate towards the receiver substrate. We demonstrate that with this technique printing of multiple cell types into 3D scaffolds is possible. Combination of LIFT and 2PP provides a route for the realization of 3D multicellular tissue constructs and artificial ECM engineered on the microscale. PMID:20811119

  7. Scaffolds: A Novel Carrier and Potential Wound Healer.

    PubMed

    Chaudhary, Chetan; Garg, Tarun

    2015-01-01

    A scaffold is comprised of the polymeric central components, which are used to deliver cells, drugs, and genes into the body. Wounds, which lead to a loss of integrity of the skin and skin mortality, are common challenges encountered in plastic and reconstructive surgery. The primary goals of treatment are rapid closure, restoration of function, and aesthetic satisfaction. A paradigm shift is taking place in medicine from using synthetic implants and tissue grafts to a tissue-engineering approach that uses degradable porous material scaffolds integrated with biological cells or molecules to regenerate tissues. Scaffold structure is a novel carrier for cell and drug delivery that enhances wound healing through differentiation of endothelial and epithelial cells and production of angiogenic growth factors in cutaneous wounds. Currently, scaffolds have application in various fields of tissue engineering in repair of nasal and auricular malformations, in bone formation, in cartilage development, in periodontal regeneration, as artificial corneas, as heart valves, in ligament replacement, in tendon repair, and in tumours. In the present review, we emphasize the role of scaffolds in wound healing, and we outline types of scaffolds, properties, techniques adopted, materials used, and their applications in tissue engineering. PMID:26080925

  8. Pore size and LbL chitosan coating influence mesenchymal stem cell in vitro fibrosis and biomineralization in 3D porous poly(epsilon-caprolactone) scaffolds.

    PubMed

    Mehr, Nima Ghavidel; Li, Xian; Chen, Gaoping; Favis, Basil D; Hoemann, Caroline D

    2015-07-01

    Poly(epsilon-caprolactone) (PCL) is a hydrophobic bioplastic under development for bone tissue engineering applications. Limited information is available on the role of internal geometry and cell-surface attachment on osseous integration potential. We tested the hypothesis that human bone marrow mesenchymal stem cells (MSCs) deposit more mineral inside porous 3D PCL scaffolds with fully interconnected 84 or 141 µm pores, when the surfaces are coated with chitosan via Layer-by-Layer (LbL)-deposited polyelectrolytes. Freshly trypsinized MSCs were seeded on PCL 3D cylinders using a novel static cold seeding method in 2% serum to optimally populate all depths of the scaffold discs, followed by 10 days of culture in proliferation medium and 21 additional days in osteogenic medium. MSCs were observed by SEM and histology to spread faster and to proliferate more on chitosan-coated pore surfaces. Most pores, with or without chitosan, became filled by collagen networks sparsely populated with fibroblast-like cells. After 21 days of culture in osteogenic medium, sporadic matrix mineralization was detected histologically and by micro-CT in highly cellular surface layers that enveloped all scaffolds and in cell aggregates in 141 µm pores near the edges. LbL-chitosan promoted punctate mineral deposition on the surfaces of 84 µm pores (p?

  9. Improved cell infiltration of highly porous nanofibrous scaffolds formed by combined fiber-fiber charge repulsions and ultra-sonication

    PubMed Central

    Jeong, Sung Isn; Burns, Nancy A.; Bonino, Christopher A.; Kwon, Il Keun; Khan, Saad A.; Alsberg, Eben

    2014-01-01

    A significant problem affecting electrospun nanofibrous tissue scaffolds is poor infiltration of cells into their three-dimensional (3D) structure. Environmental and physical manipulation, however, can enhance cellular infiltration into electrospun scaffolds. In this work, RGD-modified alginate mats with increased thickness and porosity were achieved by pairing high humidity electrospinning with post-processing ultra-sonication. RGD-modified alginate, polyethylene oxide (PEO), and an FDA-approved, nonionic surfactant blends were electrospun in 20 and 50% relative humidity conditions. Mats electrospun in high humidity conditions resulted in significantly increased mat thickness and decreased fiber diameters. The mats’ alginate content was then isolated via ionic crosslinking and PEO/surfactant extraction. Finally, the alginate-only mat was post-processed by ultra-sonication to further enhance its cross-sectional thickness. Cell morphology, proliferation, and infiltration into the scaffolds were evaluated by seeding fibroblasts onto the alginate mat. Cell spreading, growth and infiltration improved with increased humidity and ultra-sonication. This approach shows great promise for the design of cell-permeable nanofibrous scaffolds for tissue-engineering applications. PMID:25530854

  10. Influence of 3D porous galactose containing PVA/gelatin hydrogel scaffolds on three-dimensional spheroidal morphology of hepatocytes.

    PubMed

    Vasanthan, Kirthanashri S; Subramaniam, Anuradha; Krishnan, Uma Maheswari; Sethuraman, Swaminathan

    2015-01-01

    Three-dimensional liver scaffolds are temporary framework that mimics native ECM architecture and positively influence hepatocyte lodging, proliferation with retention of metabolic activities. The aim of the current study is to develop galactose containing physical cross-linked polyvinyl alcohol/gelatin (P/G 8:2 and 9:1) hydrogel scaffolds via freeze/thaw technique. The 8:2 and 9:1 P/G hydrogels exhibited comparable pore size and porosity (P > 0.05). The tensile strength of the fabricated 8:2 and 9:1 P/G hydrogel scaffolds were found to be in accordance with native human liver. Pore interconnectivity of both the P/G hydrogel scaffolds was confirmed by scanning electron micrographs and liquid displacement method. Further galactose containing hydrogel promoted cell-cell and cell-hydrogel interaction, aiding cellular aggregation leading to spheroids formation compared to void P/G hydrogel by 7 days. Hence, galactose containing P/G hydrogel could be more promising substrate as it showed significantly higher cell proliferation and albumin secretion for 21 days when compared to non-galactose P/G hydrogels (P < 0.05). PMID:25578699

  11. Protein-releasing polymeric scaffolds induce fibrochondrocytic differentiation of endogenous cells for knee meniscus regeneration in sheep

    PubMed Central

    Lee, Chang H.; Rodeo, Scott A.; Fortier, Lisa Ann; Lu, Chuanyong; Erisken, Cevat

    2015-01-01

    Regeneration of complex tissues, such as kidney, liver, and cartilage, continues to be a scientific and translational challenge. Survival of ex vivo cultured, transplanted cells in tissue grafts is among one of the key barriers. Meniscus is a complex tissue consisting of collagen fibers and proteoglycans with gradient phenotypes of fibrocartilage and functions to provide congruence of the knee joint, without which the patient is likely to develop arthritis. Endogenous stem/progenitor cells regenerated the knee meniscus upon spatially released human connective tissue growth factor (CTGF) and transforming growth factor–?3 (TGF?3) from a three-dimensional (3D)–printed biomaterial, enabling functional knee recovery. Sequentially applied CTGF and TGF?3 were necessary and sufficient to propel mesenchymal stem/progenitor cells, as a heterogeneous population or as single-cell progenies, into fibrochondrocytes that concurrently synthesized procollagens I and II?. When released from microchannels of 3D–printed, human meniscus scaffolds, CTGF and TGF?3 induced endogenous stem/progenitor cells to differentiate and synthesize zone-specific type I and II collagens. We then replaced sheep meniscus with anatomically correct, 3D–printed scaffolds that incorporated spatially delivered CTGF and TGF?3. Endogenous cells regenerated the meniscus with zone-specific matrix phenotypes: primarily type I collagen in the outer zone, and type II collagen in the inner zone, reminiscent of the native meniscus. Spatiotemporally delivered CTGF and TGF?3 also restored inhomogeneous mechanical properties in the regenerated sheep meniscus. Survival and directed differentiation of endogenous cells in a tissue defect may have implications in the regeneration of complex (heterogeneous) tissues and organs. PMID:25504882

  12. Enzymatic mineralization of silk scaffolds.

    PubMed

    Samal, Sangram K; Dash, Mamoni; Declercq, Heidi A; Gheysens, Tom; Dendooven, Jolien; Van Der Voort, Pascal; Cornelissen, Ria; Dubruel, Peter; Kaplan, David L

    2014-07-01

    The present study focuses on the alkaline phosphatase (ALP) mediated formation of apatitic minerals on porous silk fibroin protein (SFP) scaffolds. Porous SFP scaffolds impregnated with different concentrations of ALP are homogeneously mineralized under physiological conditions. The mineral structure is apatite while the structures differ as a function of the ALP concentration. Cellular adhesion, proliferation, and colonization of osteogenic MC3T3 cells improve on the mineralized SFP scaffolds. These findings suggest a simple process to generate mineralized scaffolds that can be used to enhanced bone tissue engineering-related utility. PMID:24610728

  13. Fabrication of porous scaffolds by three-dimensional plotting of a pasty calcium phosphate bone cement under mild conditions.

    PubMed

    Lode, Anja; Meissner, Katrin; Luo, Yongxiang; Sonntag, Frank; Glorius, Stefan; Nies, Berthold; Vater, Corina; Despang, Florian; Hanke, Thomas; Gelinsky, Michael

    2014-09-01

    The major advantage of hydroxyapatite (HA)-forming calcium phosphate cements (CPCs) used as bone replacement materials is their setting under physiological conditions without the necessity for thermal treatment that allows the incorporation of biological factors. In the present study, we have combined the biocompatible consolidation of CPCs with the potential of rapid prototyping (RP) techniques to generate calcium phosphate-based scaffolds with defined inner and outer morphology. We demonstrate the application of the RP technique three-dimensional (3D) plotting for the fabrication of HA cement scaffolds. This was realized by utilizing a paste-like CPC (P-CPC) which is stable as a malleable paste and whose setting reaction is initiated only after contact with aqueous solutions. The P-CPC showed good processability in the 3D plotting process and allowed the fabrication of stable?3D structures of different geometries with adequate mechanical stability and compressive strength. The cytocompatibility of the plotted P-CPC scaffolds was demonstrated in a cell culture experiment with human mesenchymal stem cells. The mild conditions during 3D plotting and post-processing and the realization of the whole procedure under sterile conditions make this approach highly attractive for fabrication of individualized implants with respect to patient-specific requirements by simultaneous plotting of biological components. PMID:22933381

  14. Ectopic osteochondral formation of biomimetic porous PVA-n-HA/PA6 bilayered scaffold and BMSCs construct in rabbit.

    PubMed

    Qu, Dan; Li, Jihua; Li, Yubao; Khadka, Ashish; Zuo, Yi; Wang, Hang; Liu, Yiming; Cheng, Lin

    2011-01-01

    In this work, the novel poly vinyl alcohol/gelatin-nano-hydroxyapatite/polyamide6 (PVA-n-HA/PA6) bilayered scaffold with biomimetic properties for articular cartilage and subchondral bone is developed. Furthermore, when these osteochondral scaffolds were seeded with induced bone mesenchymal stem cells (BMSCs) and implanted at ectopic sites, showed the potential for an engineered cartilage tissue and the corresponding subchondral bone. BMSCs were expanded in vitro and induced to chondrogenic or osteogenic potential by culturing in suitable media for 14 days. Subsequently, these induced cells were seeded into PVA-n-HA/PA6 separately, and the constructs were implanted into the rabbit muscle pouch for upto 12 weeks. Ectopic neocartilage formation in the PVA layer and reconstitution of the subchondral bone which remained confined within the n-HA/PA6 layer with the alteration of the cellular phenotype were identified with Masson's trichrome stain. Simultaneously, the RT-PCR results confirmed the expression of specific extracellular matrix (ECM) markers for cartilaginous tissue, such as collagen type II (Col-II), or alternatively, markers for osteoid tissue, such as collagen type I (Col-I) at the corresponding layers. During ectopic implantation, the underlying subchondral bone layer was completely integrated with the cartilage layer. The result from the ectopic osteochondral scaffolds implantation suggests that PVA-n-HA/PA6 with induced BMSCs is a possible substitute with potential in cartilage repair strategies. PMID:20967773

  15. Functionalized ultra-porous titania nanofiber membranes as nuclear waste separation and sequestration scaffolds for nuclear fuels recycle.

    SciTech Connect

    Liu, Haiqing; Bell, Nelson Simmons; Cipiti, Benjamin B.; Lewis, Tom Goslee,; Sava, Dorina Florentina; Nenoff, Tina Maria

    2012-09-01

    Advanced nuclear fuel cycle concept is interested in reducing separations to a simplified, one-step process if possible. This will benefit from the development of a one-step universal getter and sequestration material so as a simplified, universal waste form was proposed in this project. We have developed a technique combining a modified sol-gel chemistry and electrospinning for producing ultra-porous ceramic nanofiber membranes with controllable diameters and porous structures as the separation/sequestration materials. These ceramic nanofiber materials have been determined to have high porosity, permeability, loading capacity, and stability in extreme conditions. These porous fiber membranes were functionalized with silver nanoparticles and nanocrystal metal organic frameworks (MOFs) to introduce specific sites to capture gas species that are released during spent nuclear fuel reprocessing. Encapsulation into a durable waste form of ceramic composition was also demonstrated.

  16. Characterization of highly porous polymeric materials with pore diameters larger than 100 nm by mercury porosimetry and X-ray scattering methods.

    PubMed

    Egger, C C; du Fresne, C; Raman, V I; Schädler, V; Frechen, T; Roth, S V; Müller-Buschbaum, P

    2008-06-01

    Highly porous polymeric materials with pore sizes ranging from 100 nm to 1 microm are a very challenging class of materials not only to prepare synthetically (due to the high capillary pressures generated upon solvent removal) but also to characterize structurally. Through the examples of three different types of porous compounds synthesized in our laboratory (i) high-density melamine-based "MF-hd" with monomodal pore diameters around 500-900 nm, (ii) low-density melamine-based "MF-ld" with bimodal pore size distribution and average diameters around 2.3 microm and 350 nm, (iii) highly porous polyurethane "PU" with monomodal pore sizes around 150 nm, we confirm the limitations of mercury porosimetry as a means to investigate the architecture of materials with very high porosity (>80 vol %) and low compressive strength. Instead, a combination of high-resolution scanning electron microscopy and small-angle and ultrasmall-angle X-ray scattering (SAXS and USAXS, respectively) studies of these three types of materials helps in determining both the network and the pore structures. This work elucidates the need and applicability of the SAXS/USAXS techniques in characterizing such porous materials. For instance, the polyurethane specimens can only be quantitatively characterized by scattering techniques, the results of which are corroborated by high-resolution scanning electron microscopy observations. PMID:18442280

  17. Novel bioactive polyester scaffolds prepared from unsaturated resins based on isosorbide and succinic acid.

    PubMed

    Smiga-Matuszowicz, Monika; Janicki, Bartosz; Jaszcz, Katarzyna; ?ukaszczyk, Jan; Kaczmarek, Marcin; Lesiak, Marta; Siero?, Aleksander L; Simka, Wojciech; Mierzwi?ski, Maciej; Kusz, Damian

    2014-12-01

    In this study new biodegradable materials obtained by crosslinking poly(3-allyloxy-1,2-propylene succinate) (PSAGE) with oligo(isosorbide maleate) (OMIS) and small amount of methyl methacrylate were investigated. The porous scaffolds were obtained in the presence of a foaming system consisted of calcium carbonate/carboxylic acid mixture, creating in situ porous structure during crosslinking of liquid formulations. The maximum crosslinking temperature and setting time, the cured porous materials morphology as well as the effect of their porosity on mechanical properties and hydrolytic degradation process were evaluated. It was found that the kind of carboxylic acid used in the foaming system influenced compressive strength and compressive modulus of porous scaffolds. The MTS cytotoxicity assay was carried out for OMIS using hFOB1.19 cell line. OMIS resin was found to be non-toxic in wide range of concentrations. On the ground of scanning electron microscopy (SEM) observations and energy X-ray dispersive analysis (EDX) it was found that hydroxyapatite (HA) formation at the scaffolds surfaces within short period of soaking in phosphate buffer solution occurs. After 3h immersion a compact layer of HA was observed at the surface of the samples. The obtained results suggest potential applicability of resulted new porous crosslinked polymeric materials as temporary bone void fillers. PMID:25491802

  18. 3D Porous Calcium-Alginate Scaffolds Cell Culture System Improved Human Osteoblast Cell Clusters for Cell Therapy

    PubMed Central

    Chen, Ching-Yun; Ke, Cherng-Jyh; Yen, Ko-Chung; Hsieh, Hui-Chen; Sun, Jui-Sheng; Lin, Feng-Huei

    2015-01-01

    Age-related orthopedic disorders and bone defects have become a critical public health issue, and cell-based therapy is potentially a novel solution for issues surrounding bone tissue engineering and regenerative medicine. Long-term cultures of primary bone cells exhibit phenotypic and functional degeneration; therefore, culturing cells or tissues suitable for clinical use remain a challenge. A platform consisting of human osteoblasts (hOBs), calcium-alginate (Ca-Alginate) scaffolds, and a self-made bioreactor system was established for autologous transplantation of human osteoblast cell clusters. The Ca-Alginate scaffold facilitated the growth and differentiation of human bone cell clusters, and the functionally-closed process bioreactor system supplied the soluble nutrients and osteogenic signals required to maintain the cell viability. This system preserved the proliferative ability of cells and cell viability and up-regulated bone-related gene expression and biological apatite crystals formation. The bone-like tissue generated could be extracted by removal of calcium ions via ethylenediaminetetraacetic acid (EDTA) chelation, and exhibited a size suitable for injection. The described strategy could be used in therapeutic application and opens new avenues for surgical interventions to correct skeletal defects. PMID:25825603

  19. Highly porous Zinc Stannate (Zn2SnO4) nanofibers scaffold photoelectrodes for efficient methyl ammonium halide perovskite solar cells

    PubMed Central

    Mali, Sawanta S.; Su Shim, Chang; Kook Hong, Chang

    2015-01-01

    Development of ternary metal oxide (TMO) based electron transporting layer (ETL) for perovskite solar cell open a new approaches toward efficient a unique strategy for solid state dye-sensitized solar cells (ssDSSCs). In the present investigation, highly porous zinc tin oxide (Zn2SnO4) scaffold nanofibers has been synthesized by electrospinning technique and successfully used for methyl ammonium lead halide (CH3NH3PbI3) perovskite sensitized solid state solar cells. The fabricated optimized perovskite solar cell devices exhibited 7.38% power conversion efficiency (PCE) with open circuit voltage (VOC) 0.986?V, current density (JSC)?=?12.68?mAcm-2 and fill factor (FF) 0.59 under AM 1.5?G sunlight (100?mWcm?2) which is higher than Zn2SnO4 nanoparticle (??=?2.52%) based perovskite solar cells. This improvement is achieved due to high porosity of Zn2SnO4 nanofibers and high crystallinity of the nanofibers synthesized at 700?°C. These results are remarkably higher than reported perovskite solar cells based on such type of ternary metal oxide ETLs. PMID:26094863

  20. Highly porous Zinc Stannate (Zn2SnO4) nanofibers scaffold photoelectrodes for efficient methyl ammonium halide perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Mali, Sawanta S.; Su Shim, Chang; Kook Hong, Chang

    2015-06-01

    Development of ternary metal oxide (TMO) based electron transporting layer (ETL) for perovskite solar cell open a new approaches toward efficient a unique strategy for solid state dye-sensitized solar cells (ssDSSCs). In the present investigation, highly porous zinc tin oxide (Zn2SnO4) scaffold nanofibers has been synthesized by electrospinning technique and successfully used for methyl ammonium lead halide (CH3NH3PbI3) perovskite sensitized solid state solar cells. The fabricated optimized perovskite solar cell devices exhibited 7.38% power conversion efficiency (PCE) with open circuit voltage (VOC) 0.986?V, current density (JSC)?=?12.68?mAcm-2 and fill factor (FF) 0.59 under AM 1.5?G sunlight (100?mWcm-2) which is higher than Zn2SnO4 nanoparticle (??=?2.52%) based perovskite solar cells. This improvement is achieved due to high porosity of Zn2SnO4 nanofibers and high crystallinity of the nanofibers synthesized at 700?°C. These results are remarkably higher than reported perovskite solar cells based on such type of ternary metal oxide ETLs.

  1. An Open Source Image Processing Method to Quantitatively Assess Tissue Growth after Non-Invasive Magnetic Resonance Imaging in Human Bone Marrow Stromal Cell Seeded 3D Polymeric Scaffolds

    PubMed Central

    Leferink, Anne M.; Fratila, Raluca M.; Koenrades, Maaike A.; van Blitterswijk, Clemens A.; Velders, Aldrik; Moroni, Lorenzo

    2014-01-01

    Monitoring extracellular matrix (ECM) components is one of the key methods used to determine tissue quality in three-dimensional (3D) scaffolds for regenerative medicine and clinical purposes. This is even more important when multipotent human bone marrow stromal cells (hMSCs) are used, as it could offer a method to understand in real time the dynamics of stromal cell differentiation and eventually steer it into the desired lineage. Magnetic Resonance Imaging (MRI) is a promising tool to overcome the challenge of a limited transparency in opaque 3D scaffolds. Technical limitations of MRI involve non-uniform background intensity leading to fluctuating background signals and therewith complicating quantifications on the retrieved images. We present a post-imaging processing sequence that is able to correct for this non-uniform background intensity. To test the processing sequence we investigated the use of MRI for in vitro monitoring of tissue growth in three-dimensional poly(ethylene oxide terephthalate)–poly(butylene terephthalate) (PEOT/PBT) scaffolds. Results showed that MRI, without the need to use contrast agents, is a promising non-invasive tool to quantitatively monitor ECM production and cell distribution during in vitro culture in 3D porous tissue engineered constructs. PMID:25502022

  2. High-precision flexible fabrication of tissue engineering scaffolds using distinct polymers

    SciTech Connect

    Wei, Chuang; Cai, Lei; Sonawane, Bhushan; Wang, Shanfeng; Dong, Jingyan

    2012-01-01

    Three-dimensional porous structures using biodegradable materials with excellent biocompatibility are critically important for tissue engineering applications. We present a multi-nozzle-based versatile deposition approach to flexibly construct porous tissue engineering scaffolds using distinct polymeric biomaterials such as thermoplastic and photo-crosslinkable polymers. We first describe the development of the deposition system and fabrication of scaffolds from two types of biodegradable polymers using this system. The thermoplastic sample is semi-crystalline poly({var_epsilon}-caprolactone) (PCL) that can be processed at a temperature higher than its melting point and solidifies at room temperature. The photo-crosslinkable one is polypropylene fumarate (PPF) that has to be dissolved in a reactive solvent as a resin for being cured into solid structures. Besides the direct fabrication of thermoplastic PCL scaffolds, we specifically develop a layer molding approach for the fabrication of crosslinkable polymers, which traditionally can only be fabricated by stereolithography. In this approach, a thermoplastic supporting material (paraffin wax) is first deposited to make a mold for each specific layer, and then PPF is deposited on demand to fill the mold and cured by the UV light. The supporting material can be removed to produce a porous scaffold of crosslinked PPF. Both PCL and crosslinked PPF scaffolds fabricated using the developed system have been characterized in terms of compressive mechanical properties, morphology, pore size and porosity. Mouse MC3T3-E1 pre-osteoblastic cell studies on the fabricated scaffolds have been performed to demonstrate their capability of supporting cell proliferation and ingrowth, aiming for bone tissue engineering applications.

  3. Biomimetic synthesis of hierarchically porous nanostructured metal oxide microparticles--potential scaffolds for drug delivery and catalysis.

    PubMed

    Seisenbaeva, Gulaim A; Moloney, Micheal P; Tekoriute, Renata; Hardy-Dessources, Adeline; Nedelec, Jean-Marie; Gun'ko, Yurii K; Kessler, Vadim G

    2010-06-15

    Hierarchically porous hybrid microparticles, strikingly reminiscent in their structure of the silica skeletons of single-cell algae, diatoms, but composed of titanium dioxide, and the chemically bound amphiphilic amino acids or small proteins can be prepared by a simple one-step biomimetic procedure, using hydrolysis of titanium alkoxides modified by these ligands. The growth of the hierarchical structure results from the conditions mimicking the growth of skeletons in real diatoms--the self-assembly of hydrolysis-generated titanium dioxide nanoparticles, templated by the microemulsion, originating from mixing the hydrocarbon solvent and water on action of amino acids as surfactants. The obtained microsize nanoparticle aggregates possess remarkable chemical and thermal stability and are promising substrates for applications in drug delivery and catalysis. They can be provided with pronounced surface chirality through application of chiral modifying ligands. They display also high selectivity in sorption of phosphorylated biomolecules or medicines as demonstrated by (1)H and (31)P NMR studies and by in vitro modeling using (32)P-marked ATP as a substrate. The release of the adsorbed model compounds in an inert medium is a very slow process directed by desorption kinetics. It is enhanced, however, noticeably in contact with biological fluids modeling those of the tissues suffering inflammation, which makes the produced material highly attractive for application in medical implants. The developed synthetic approach has been applied successfully also for the preparation of analogous hybrid microparticles based on zirconium dioxide or aluminum sesquioxide. PMID:20230060

  4. Enhanced survival and function of islet-like clusters differentiated from adipose stem cells on a three-dimensional natural polymeric scaffold: an in vitro study.

    PubMed

    Aloysious, Neena; Nair, Prabha D

    2014-05-01

    Autologous adipose stem cells owing to its pluripotent nature offer a valuable source for pancreatic beta cell replacement in the treatment of diabetes mellitus. However, maintaining longevity and functionality of stem cell-derived islet-like cells for long-term in vitro culture is challenging. Signaling interaction between islets and surrounding extracellular matrix (ECM) is an important factor for islet survival and function. Tissue engineering strategy to use scaffolds as substitute for ECM is a key to the problem. In the present study, we fabricated a three-dimensional (3D) biodegradable scaffold comprised of natural polymers dextran and gelatin (DEXGEL) for differentiation of adipose stem cells to islet-like clusters (ILCs). Adipose stem cells derived from subcutaneous fat of New Zealand white rabbits were differentiated to ILCs on DEXGEL scaffold and two-dimensional (2D) culture plates via three stage protocol using cocktail of growth factors. The ILCs differentiated on DEXGEL scaffold exhibited characteristic islet morphology, and expressed islet-specific hormones (insulin, glucagon, and somatostatin). The insulin secretion in response to glucose challenge and viability of ILCs on DEXGEL scaffold were significantly higher in comparison to ILCs on 2D culture. Our results demonstrated for the first time that DEXGEL scaffold simulated an extracellular environment for effective differentiation of rabbit adipose stem cells to ILCs. PMID:24359126

  5. A biodegradable polymeric system for peptide–protein delivery assembled with porous microspheres and nanoparticles, using an adsorption/infiltration process

    PubMed Central

    Alcalá-Alcalá, Sergio; Urbán-Morlán, Zaida; Aguilar-Rosas, Irene; Quintanar-Guerrero, David

    2013-01-01

    A biodegradable polymeric system is proposed for formulating peptides and proteins. The systems were assembled through the adsorption of biodegradable polymeric nanoparticles onto porous, biodegradable microspheres by an adsorption/infiltration process with the use of an immersion method. The peptide drug is not involved in the manufacturing of the nanoparticles or in obtaining the microspheres; thus, contact with the organic solvent, interfaces, and shear forces required for the process are prevented during drug loading. Leuprolide acetate was used as the model peptide, and poly(d,l-lactide-co-glycolide) (PLGA) was used as the biodegradable polymer. Leuprolide was adsorbed onto different amounts of PLGA nanoparticles (25 mg/mL, 50 mg/mL, 75 mg/mL, and 100 mg/mL) in a first stage; then, these were infiltrated into porous PLGA microspheres (100 mg) by dipping the structures into a microsphere suspension. In this way, the leuprolide was adsorbed onto both surfaces (ie, nanoparticles and microspheres). Scanning electron microscopy studies revealed the formation of a nanoparticle film on the porous microsphere surface that becomes more continuous as the amount of infiltrated nanoparticles increases. The adsorption efficiency and release rate are dependent on the amount of adsorbed nanoparticles. As expected, a greater adsorption efficiency (~95%) and a slower release rate were seen (~20% of released leuprolide in 12 hours) when a larger amount of nanoparticles was adsorbed (100 mg/mL of nanoparticles). Leuprolide acetate begins to be released immediately when there are no infiltrated nanoparticles, and 90% of the peptide is released in the first 12 hours. In contrast, the systems assembled in this study released less than 44% of the loaded drug during the same period of time. The observed release profiles denoted a Fickian diffusion that fit Higuchi’s model (t1/2). The manufacturing process presented here may be useful as a potential alternative for formulating injectable depots for sensitive hydrophilic drugs such as peptides and proteins, among others. PMID:23788833

  6. Micro-structured polymer scaffolds fabricated by direct laser writing for tissue engineering

    NASA Astrophysics Data System (ADS)

    Danilevicius, Paulius; Rekstyte, Sima; Balciunas, Evaldas; Kraniauskas, Antanas; Jarasiene, Rasa; Sirmenis, Raimondas; Baltriukiene, Daiva; Bukelskiene, Virginija; Gadonas, Roaldas; Malinauskas, Mangirdas

    2012-08-01

    This work presents the latest results on direct laser writing of polymeric materials for tissue engineering applications. A femtosecond Yb:KGW laser (300 fs, 200 kHz, 515 nm) was used as a light source for non-linear lithography. Fabrication was implemented in various photosensitive polymeric materials, such as: hybrid organic-inorganic sol-gel based on silicon-zirconium oxides, commercial ORMOCER class photoresins. These materials were structured via multi-photon polymerization technique with submicron resolution. Porous three-dimensional scaffolds for artificial tissue engineering were fabricated with constructed system and were up to several millimeters in overall size with 10 to 100 ?m internal pores. Biocompatibility of the used materials was tested in primary rabbit muscle-derived stem cell culture in vitro and using laboratory rats in vivo. This interdisciplinary study suggests that proposed technique and materials are suitable for tissue engineering applications.

  7. Osteogenesis and angiogenesis induced by porous ?-CaSiO(3)/PDLGA composite scaffold via activation of AMPK/ERK1/2 and PI3K/Akt pathways.

    PubMed

    Wang, Chen; Lin, Kaili; Chang, Jiang; Sun, Jiao

    2013-01-01

    As a potential bioactive material, ?-calcium silicate (?-CS) has attracted particular attention in the field of bone regeneration. In this study, porous ?-CS/Poly-D,L-Lactide-Glycolide (PDLGA) composite scaffolds were developed with the goals of controlling the degradation rate and improving the mechanical and biological properties. The compressive strength and toughness were significantly enhanced by PDLGA modification of porous ?-CS ceramic scaffolds. The effects of the ionic extract from ?-CS/PDLGA composite scaffolds on osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs), proliferation of human umbilical vein endothelial cells (HUVECs) and the related mechanisms were investigated. It was shown that bioactive ions from ?-CS/PDLGA scaffolds could enhance cell viability, alkaline phosphatase (ALP) activity, calcium mineral deposition, and mRNA expression levels of osteoblast-related genes of rBMSCs without addition of extra osteogenic reagents. The activation in AMP-activated protein kinase (AMPK), extracellular signal-related kinases (ERK) 1/2 and RUNX-2 were observed in rBMSCs cultured in the extract of ?-CS/PDLGA, and these effects could be blocked by AMPK inhibitor Compound C. The extracts of ?-CS/PDLGA composites stimulated HUVECs proliferation that was associated with phosphorylation of protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS) as well as an increase in nitric oxide (NO) production and secretion of vascular endothelial growth factor (VEGF). The inductions were abolished by the addition of phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. The composite scaffolds were implanted in critical sized rabbit femur defects (6 × 10 mm) for 4, 12 and 20 weeks with ?-tricalcium phosphate (?-TCP) as controls. Sequential histological evaluations and radiographs revealed that ?-CS/PDLGA dramatically stimulated new bone formation and angiogenesis. The biodegradation rate of the ?-CS/PDLGA scaffolds was lower than that of ?-TCP at each time point examined, and matched the new bone formation rates. These data suggest that ?-CS/PDLGA could promote bone regeneration in vivo, which might be ascribed to the enhanced osteogenic differentiation of mesenchymal stem cells (MSCs) and increased angiogenic activity of endothelial cells (ECs). PMID:23069715

  8. Differentiation capacity and maintenance of differentiated phenotypes of human mesenchymal stromal cells cultured on two distinct types of 3D polymeric scaffolds.

    PubMed

    Leferink, A M; Santos, D; Karperien, M; Truckenmüller, R K; van Blitterswijk, C A; Moroni, L

    2015-12-30

    Many studies have shown the influence of soluble factors and material properties on the differentiation capacity of mesenchymal stromal cells (MSCs) cultured as monolayers. These types of two-dimensional (2D) studies can be used as simplified models to understand cell processes related to stem cell sensing and mechano-transduction in a three-dimensional (3D) context. For several other mechanisms such as cell-cell signaling, cell proliferation and cell morphology, it is well-known that cells behave differently on a planar surface compared to cells in 3D environments. In classical tissue engineering approaches, a combination of cells, 3D scaffolds and soluble factors are considered as the key ingredients for the generation of mechanically stable 3D tissue constructs. However, when MSCs are used for tissue engineering strategies, little is known about the maintenance of their differentiation potential in 3D scaffolds after the removal of differentiation soluble factors. In this study, the differentiation potential of human MSCs (hMSCs) into the chondrogenic and osteogenic lineages on two distinct 3D scaffolds, additive manufactured electrospun scaffolds, was assessed and compared to conventional 2D culture. Human MSCs cultured in the presence of soluble factors in 3D showed to differentiate to the same extent as hMSCs cultured as 2D monolayers or as scaffold-free pellets, indicating that the two scaffolds do not play a consistent role in the differentiation process. In the case of phenotypic changes, the achieved differentiated phenotype was not maintained after the removal of soluble factors, suggesting that the plasticity of hMSCs is retained in 3D cell culture systems. This finding can have implications for future tissue engineering approaches in which the validation of hMSC differentiation on 3D scaffolds will not be sufficient to ensure the maintenance of the functionality of the cells in the absence of appropriate differentiation signals. PMID:26566169

  9. In situ synthesis of molecularly imprinted nanoparticles in porous support membranes using high-viscosity polymerization solvents.

    PubMed

    Renkecz, Tibor; László, Krisztina; Horváth, Viola

    2012-06-01

    There is a growing need in membrane separations for novel membrane materials providing selective retention. Molecularly imprinted polymers (MIPs) are promising candidates for membrane functionalization. In this work, a novel approach is described to prepare composite membrane adsorbers incorporating molecularly imprinted microparticles or nanoparticles into commercially available macroporous filtration membranes. The polymerization is carried out in highly viscous polymerization solvents, and the particles are formed in situ in the pores of the support membrane. MIP particle composite membranes selective for terbutylazine were prepared and characterized by scanning electron microscopy and N? porosimetry. By varying the polymerization solvent microparticles or nanoparticles with diameters ranging from several hundred nanometers to 1 µm could be embedded into the support. The permeability of the membranes was in the range of 1000 to 20,000 Lm?² ?hr?¹ ?bar?¹. The imprinted composite membranes showed high MIP/NIP (nonimprinted polymer) selectivity for the template in organic media both in equilibrium-rebinding measurements and in filtration experiments. The solid phase extraction of a mixture of the template, its analogs, and a nonrelated compound demonstrated MIP/NIP selectivity and substance selectivity of the new molecularly imprinted membrane. The synthesis technique offers a potential for the cost-effective production of selective membrane adsorbers with high capacity and high throughput. PMID:22641529

  10. Dynamic compression combined with SOX-9 overexpression in rabbit adipose-derived mesenchymal stem cells cultured in a three-dimensional gradual porous PLGA composite scaffold upregulates HIF-1? expression.

    PubMed

    Chen, Xu; Li, Jianjun; Wang, Enbo; Zhao, Qun; Kong, Zhan; Yuan, Xiangnan

    2015-12-01

    There is considerable interest in how the fate of adipose-derived stem cells is determined. Physical stimuli play a crucial role in skeletogenesis and in cartilage repair and regeneration. In the present study, we investigated the comparative and interactive effects of dynamic compression and SRY-related high-mobility group box gene-9 (SOX-9) on chondrogenesis of rabbit adipose-derived stem cells in three-dimensional gradual porous PLGA (polylactic-co-glycolic acid) composite scaffolds. Articular cartilage is stratified into zones delineated by characteristic changes in cellular, matrix, and nutritive components. As a consequence, biochemical and biomechanical properties vary greatly between the different zones, giving the tissue its unique structure and, thus, the ability to cope with extreme loading. The effects on development of the cartilage were examined using a combination of computational modeling to predict alterations in biophysical stimuli, detailed morphometric analysis of 3D digital representations. In addition, early chondrogenic differentiation was assessed via real-time PCR of mRNA expression levels for bone- and cartilage-specific gene markers. Our findings define the important role of dynamic compression combined with SOX-9 overexpression during in vitro generation of tissue-engineering cartilage and suggest that a 3D gradual porous PLGA composite scaffold may benefit articular cartilage tissue engineering in cartilage regeneration for better force distribution. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3886-3895, 2015. PMID:26123537

  11. Hybrid use of combined and sequential delivery of growth factors and ultrasound stimulation in porous multilayer composite scaffolds to promote both vascularization and bone formation in bone tissue engineering.

    PubMed

    Yan, Haoran; Liu, Xia; Zhu, Minghua; Luo, Guilin; Sun, Tao; Peng, Qiang; Zeng, Yi; Chen, Taijun; Wang, Yingying; Liu, Keliang; Feng, Bo; Weng, Jie; Wang, Jianxin

    2016-01-01

    In this study, a multilayer coating technology would be adopted to prepare a porous composite scaffold and the growth factor release and ultrasound techniques were introduced into bone tissue engineering to finally solve the problems of vascularization and bone formation in the scaffold whilst the designed multilayer composite with gradient degradation characteristics in the space was used to match the new bone growth process better. The results of animal experiments showed that the use of low intensity pulsed ultrasound (LIPUS) combined with growth factors demonstrated excellent capabilities and advantages in both vascularization and new bone formation in bone tissue engineering. The degradation of the used scaffold materials could match new bone formation very well. The results also showed that only RGD-promoted cell adhesion was insufficient to satisfy the needs of new bone formation while growth factors and LIPUS stimulation were the key factors in new bone formation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 195-208, 2016. PMID:26282063

  12. Nano/microfibrous polymeric constructs loaded with bioactive agents and designed for tissue engineering applications: a review.

    PubMed

    Puppi, Dario; Zhang, Xuanmiao; Yang, Likai; Chiellini, Federica; Sun, Xun; Chiellini, Emo

    2014-10-01

    Nano/microfibrous polymeric constructs present various inherent advantages, such as highly porous architecture and high surface to volume ratio, making them attractive for tissue engineering purposes. Electrospinning is the most preferred technique for the fabrication of polymeric nanofibrous assemblies that can mimic the physical functions of native extracellular matrix greatly favoring cells attachment and thus influencing their morphology and activities. Different approaches have been developed to apply polymeric microfiber fabrication techniques (e.g. wet-spinning) for the obtainment of scaffolds with a three-dimensional network of micropores suitable for effective cells migration. Progress in additive manufacturing technology has led to the development of complex scaffold's shapes and microfibrous structures with a high degree of automation, good accuracy and reproducibility. Various loading methods, such as direct blending, coaxial electrospinning and microparticles incorporation, are enabling to develop customized strategies for the biofunctionalization of nano/microfibrous scaffolds with a tailored kinetics of release of different bioactive agents, ranging from small molecules, such as antibiotics, to protein drugs, such as growth factors, and even cells. Recent activities on the combination of different processing techniques and loading methods for the obtainment of biofunctionalized polymeric constructs with a complex multiscale structure open new possibilities for the development of biomimetic scaffolds endowed with a hierarchical architecture and a sophisticated release kinetics of different bioactive agents. This review is aimed at summarizing current advances in technologies and methods for manufacturing nano/microfibrous polymeric constructs suitable as tissue engineering scaffolds, and for their combination with different bioactive agents to promote tissue regeneration and therapeutic effects. PMID:24678016

  13. A Bi-Layered Elastomeric Scaffold for Tissue Engineering of Small-Diameter Vascular Grafts

    PubMed Central

    Soletti, Lorenzo; Hong, Yi; Guan, Jianjun; Stankus, John J.; El-Kurdi, Mohammed S.; Wagner, William R.; Vorp, David A.

    2011-01-01

    A major barrier in the development of a clinically-useful small-diameter tissue engineered vascular graft (TEVG) is the scaffold component. Scaffold requirements include matching the mechanical and structural properties with those of native vessels and optimizing the microenvironment to foster cell integration, adhesion, and growth. We have developed a small-diameter, bi-layered, biodegradable, elastomeric scaffold based on a synthetic, biodegradable elastomer. The scaffold incorporates a highly porous inner layer, allowing cell integration and growth, and an external, fibrous reinforcing layer deposited by electrospinning. Scaffold morphology and mechanical properties were assessed, quantified, and compared to those of native vessels. Scaffolds were then seeded with adult stem cells via a rotational vacuum seeding device to obtain a TEVG, cultured in dynamic conditions for 7 days, and evaluated for cellularity. The scaffold showed a firm integration of the two polymeric layers with no delaminations. Mechanical properties were physiologically-consistent showing anisotropy, elastic modulus (1.4±0.4 MPa), and ultimate tensile stress (8.3±1.7 MPa) comparable with native vessels. Compliance and suture retention force were 4.6±0.5×10?4 mmHg?1 and 3.4±0.3 N, respectively. Seeding resulted in a rapid, uniform, bulk integration of cells, with a seeding efficiency of 92±1%. The scaffolds maintained a high level of cellular density throughout dynamic culture. This approach, combining artery-like mechanical properties and a rapid and efficient cellularization, might contribute to the future clinical translation of TEVGs. PMID:19540370

  14. Fabrication of a multi-layer three-dimensional scaffold with controlled porous micro-architecture for application in small intestine tissue engineering

    PubMed Central

    Knight, Toyin; Basu, Joydeep; Rivera, Elias A.; Spencer, Thomas; Jain, Deepak; Payne, Richard

    2013-01-01

    Various methods can be employed to fabricate scaffolds with characteristics that promote cell-to-material interaction. This report examines the use of a novel technique combining compression molding with particulate leaching to create a unique multi-layered scaffold with differential porosities and pore sizes that provides a high level of control to influence cell behavior. These cell behavioral responses were primarily characterized by bridging and penetration of two cell types (epithelial and smooth muscle cells) on the scaffold in vitro. Larger pore sizes corresponded to an increase in pore penetration, and a decrease in pore bridging. In addition, smaller cells (epithelial) penetrated further into the scaffold than larger cells (smooth muscle cells). In vivo evaluation of a multi-layered scaffold was well tolerated for 75 d in a rodent model. This data shows the ability of the components of multi-layered scaffolds to influence cell behavior, and demonstrates the potential for these scaffolds to promote desired tissue outcomes in vivo. PMID:23563499

  15. Assessment of a new biomimetic scaffold and its effects on bone formation by OCT

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Aydin, Halil M.; Piskin, Erhan; El Haj, Alicia J.

    2009-02-01

    The ultimate target of bone tissue engineering is to generate functional load bearing bone. By nature, the porous volume in the trabecular bone is occupied by osseous medulla. The natural bone matrix consists of hydroxyapatite (HA) crystals precipitated along the collagen type I fibres. The mineral phase renders bone strength while collagen provides flexibility. Without mineral component, bone is very flexible and can not bear loads, whereas it is brittle in the case of mineral phase without the collagen presence. In this study, we designed and prepared a new type of scaffold which mimics the features of natural bone. The scaffold consists of three different components, a biphasic polymeric base composed of two different biodegradable polymers prepared by using dual porogen approach and bioactive agents, i.e., collagen and HA particles which are distributed throughout the matrix only in the pore surfaces. Interaction of the bioactive scaffolds possessing very high porosity and interconnected pore structures with cells were investigated in a prolonged culture period by using an osteoblastic cell line. The mineral HA particles have a slight different refractive index from the other elements such as polymeric scaffolds and cell/matrix in a tissue engineering constructs, exhibiting brighter images in OCT. Thus, OCT renders a convenient means to assess the morphology and architecture of the blank biomimetic scaffolds. This study also takes a close observation of OCT images for the cultured cell-scaffold constructs in order to assess neo-formed minerals and matrix. The OCT assessments have been compared with the results from confocal and SEM analysis.

  16. Immobilization of an esterase inhibitor on a porous hollow-fiber membrane by radiation-induced graft polymerization for developing a diagnostic tool for feline kidney diseases.

    PubMed

    Matsuno, Shinya; Umeno, Daisuke; Miyazaki, Masao; Suzuta, Yasuyuki; Saito, Kyoichi; Yamashita, Tetsuro

    2013-01-01

    Removal of the major urinary protein, cauxin, a carboxylesterase, from cat urine is essential for distinguishing between physiological and abnormal proteinuria by a urine dipstick. We have previously developed a material for removing cauxin by using lens culinaris agglutinin (LCA) lectin which targets the N-linked oligosaccharides present in cauxin. To improve the affinity and specificity toward cauxin, we immobilized 1,1,1-trifluoro-3-(2-sulfanylethylsulfanyl) propane-2-one, an inhibitor of esterases, to a polymer chain grafted on to a porous hollow-fiber membrane by applying radiation-induced graft polymerization. Normal male urine was forced to permeate through the pores rimmed by the ligand-immobilized polymer chain. Cauxin could not be detected in the effluent from the membrane. The residence time of the urine across a membrane thickness of 1 mm was set at 7 s. The respective dynamic and equilibrium binding capacities of the membrane for cauxin were 2 and 3 mg/g. The developed cauxin-affinity membrane material was more effective for diagnosing cat kidney diseases than the LCA lectin tip. PMID:24096669

  17. Lysis of gram-positive and gram-negative bacteria by antibacterial porous polymeric monolith formed in microfluidic biochips for sample preparation.

    PubMed

    Aly, Mohamed Aly Saad; Gauthier, Mario; Yeow, John

    2014-09-01

    Bacterial cell lysis is demonstrated using polymeric microfluidic biochips operating via a hybrid mechanical shearing/contact killing mechanism. These biochips are fabricated from a cross-linked poly(methyl methacrylate) (X-PMMA) substrate by well-controlled, high-throughput laser micromachining. The unreacted double bonds at the surface of X-PMMA provide covalent bonding for the formation of a porous polymeric monolith (PPM), thus contributing to the mechanical stability of the biochip and eliminating the need for surface treatment. The lysis efficiency of these biochips was tested for gram-positive (Enterococcus saccharolyticus and Bacillus subtilis) and gram-negative bacteria (Escherichia coli and Pseudomonas fluorescens) and confirmed by off-chip PCR without further purification. The influence of the flow rate when pumping the bacterial suspension through the PPM, and of the hydrophobic-hydrophilic balance on the cell lysis efficiency was investigated at a cell concentration of 10(5) CFU/mL. It was shown that the contribution of contact killing to cell lysis was more important than that of mechanical shearing in the PPM. The biochip showed better lysis efficiency than the off-chip chemical, mechanical, and thermal lysis techniques used in this work. The biochip also acts as a filter that isolates cell debris and allows PCR-amplifiable DNA to pass through. The system performs more efficient lysis for gram-negative than for gram-positive bacteria. The biochip does not require chemical/enzymatic reagents, power consumption, or complicated design and fabrication processes, which makes it an attractive on-chip lysis device that can be used in sample preparation for genetics and point-of-care diagnostics. The biochips were reused for 20 lysis cycles without any evidence of physical damage to the PPM, significant performance degradation, or DNA carryover when they were back-flushed between cycles. The biochips efficiently lysed both gram-positive and gram-negative bacteria in about 35 min per lysis and PPM regeneration cycle. PMID:25059724

  18. Novel Scaffolds Fabricated Using Oleuropein for Bone Tissue Engineering

    PubMed Central

    Fan, Hui; Hui, Junfeng; Duan, Zhiguang; Fan, Daidi; Mi, Yu; Deng, Jianjun; Li, Hui

    2014-01-01

    We investigated the feasibility of oleuropein as a cross-linking agent for fabricating three-dimensional (3D) porous composite scaffolds for bone tissue engineering. Human-like collagen (HLC) and nanohydroxyapatite (n-HAp) were used to fabricate the composite scaffold by way of cross-linking. The mechanical tests revealed superior properties for the cross-linked scaffolds compared to the uncross-linked scaffolds. The as-obtained composite scaffold had a 3D porous structure with pores ranging from 120 to 300??m and a porosity of 73.6 ± 2.3%. The cross-linked scaffolds were seeded with MC3T3-E1 Subclone 14 mouse osteoblasts. Fluorescence staining, the Cell Counting Kit-8 (CCK-8) assay, and scanning electron microscopy (SEM) indicated that the scaffolds enhanced cell adhesion and proliferation. Our results indicate the potential of these scaffolds for bone tissue engineering. PMID:24959582

  19. Pre-cultivation of adipose tissue-derived microvascular fragments in porous scaffolds does not improve their in vivo vascularisation potential.

    PubMed

    Laschke, M W; Kleer, S; Scheuer, C; Eglin, D; Alini, M; Menger, M D

    2015-01-01

    Adipose tissue-derived microvascular fragments represent promising vascularisation units for implanted tissue constructs. However, their reassembly into functional microvascular networks takes several days, during which the cells inside the implants are exposed to hypoxia. In the present study, we analysed whether this critical phase may be overcome by pre-cultivation of fragment-seeded scaffolds prior to their implantation. Green fluorescent protein (GFP)-positive microvascular fragments were isolated from epididymal fat pads of male C57BL/6-TgN (ACTB-EGFP) 1Osb/J mice. Nano-size hydroxyapatite particles/poly (ester-urethane) scaffolds were seeded with these fragments and cultivated for 28 days. Subsequently, these scaffolds or control scaffolds, which were freshly seeded with GFP-positive microvascular fragments, were implanted into the dorsal skinfold chamber of C57BL/6 wild-type mice to study their vascularisation and incorporation by means of intravital fluorescence microscopy, histology and immunohistochemistry over 2 weeks. Pre-cultivation of microvascular fragments resulted in the loss of their native vessel morphology. Accordingly, pre-cultivated scaffolds contained a network of individual CD31/GFP-positive endothelial cells with filigrane cell protuberances. After implantation into the dorsal skinfold chamber, these scaffolds exhibited an impaired vascularisation, as indicated by a significantly reduced functional microvessel density and lower fraction of GFP-positive microvessels in their centre when compared to freshly seeded control implants. This was associated with a deteriorated incorporation into the surrounding host tissue. These findings indicate that freshly isolated, non-cultivated microvascular fragments should be preferred as vascularisation units. This would also facilitate their use in clinical practice during intra-operative one-step procedures. PMID:25794528

  20. Development and molecular characterization of polymeric micro-nanofibrous scaffold of a defined 3-D niche for in vitro chemosensitivity analysis against acute myeloid leukemia cells

    PubMed Central

    Nair, Maya S; Mony, Ullas; Menon, Deepthy; Koyakutty, Manzoor; Sidharthan, Neeraj; Pavithran, Keechilat; Nair, Shantikumar V; Menon, Krishnakumar N

    2015-01-01

    Standard in vitro drug testing employs 2-D tissue culture plate systems to test anti-leukemic drugs against cell adhesion-mediated drug-resistant leukemic cells that harbor in 3-D bone marrow microenvironments. This drawback necessitates the fabrication of 3-D scaffolds that have cell adhesion-mediated drug-resistant properties similar to in vivo niches. We therefore aimed at exploiting the known property of polyurethane (PU)/poly-l-lactic acid (PLLA) in forming a micro-nanofibrous structure to fabricate unique, not presented before, as far as we are aware, 3-D micro-nanofibrous scaffold composites using a thermally induced phase separation technique. Among the different combinations of PU/PLLA composites generated, the unique PU/PLLA 60:40 composite displayed micro-nanofibrous morphology similar to decellularized bone marrow with increased protein and fibronectin adsorption. Culturing of acute myeloid leukemia (AML) KG1a cells in FN-coated PU/PLLA 60:40 shows increased cell adhesion and cell adhesion-mediated drug resistance to the drugs cytarabine and daunorubicin without changing the original CD34+/CD38?/CD33? phenotype for 168 hours compared to fibronectin tissue culture plate systems. Molecularly, as seen in vivo, increased chemoresistance is associated with the upregulation of anti-apoptotic Bcl2 and the cell cycle regulatory protein p27Kip1 leading to cell growth arrest. Abrogation of Bcl2 activity by the Bcl2-specific inhibitor ABT 737 led to cell death in the presence of both cytarabine and daunorubicin, demonstrating that the cell adhesion-mediated drug resistance induced by Bcl2 and p27Kip1 in the scaffold was similar to that seen in vivo. These results thus show the utility of a platform technology, wherein drug testing can be performed before administering to patients without the necessity for stromal cells. PMID:26028971

  1. Recent advances in bone tissue engineering scaffolds

    PubMed Central

    Bose, Susmita; Roy, Mangal; Bandyopadhyay, Amit

    2012-01-01

    Bone disorders are of significant concern due to increase in the median age of our population. Traditionally, bone grafts have been used to restore damaged bone. Synthetic biomaterials are now being used as bone graft substitutes. These biomaterials were initially selected for structural restoration based on their biomechanical properties. Later scaffolds were engineered to be bioactive or bioresorbable to enhance tissue growth. Now scaffolds are designed to induce bone formation and vascularization. These scaffolds are often porous, biodegradable materials that harbor different growth factors, drugs, genes or stem cells. In this review, we highlight recent advances in bone scaffolds and discuss aspects that still need to be improved. PMID:22939815

  2. Porous polymer networks and ion-exchange media and metal-polymer composites made therefrom

    SciTech Connect

    Kanatzidis, Mercouri G; Katsoulidis, Alexandros

    2015-03-10

    Porous polymeric networks and composite materials comprising metal nanoparticles distributed in the polymeric networks are provided. Also provided are methods for using the polymeric networks and the composite materials in liquid- and vapor-phase waste remediation applications. The porous polymeric networks, are highly porous, three-dimensional structures characterized by high surface areas. The polymeric networks comprise polymers polymerized from aldehydes and phenolic molecules.

  3. Enhancing Osteoconduction of PLLA-Based Nanocomposite Scaffolds for Bone Regeneration Using Different Biomimetic Signals to MSCs

    PubMed Central

    Ciapetti, Gabriela; Granchi, Donatella; Devescovi, Valentina; Baglio, Serena R.; Leonardi, Elisa; Martini, Desirèe; Jurado, Maria Jesus; Olalde, Beatriz; Armentano, Ilaria; Kenny, Josè M.; Walboomers, Frank X.; Alava, Josè Inaki; Baldini, Nicola

    2012-01-01

    In bone engineering, the adhesion, proliferation and differentiation of mesenchymal stromal cells rely on signaling from chemico-physical structure of the substrate, therefore prompting the design of mimetic “extracellular matrix”-like scaffolds. In this study, three-dimensional porous poly-L-lactic acid (PLLA)-based scaffolds have been mixed with different components, including single walled carbon nanotubes (CNT), micro-hydroxyapatite particles (HA), and BMP2, and treated with plasma (PT), to obtain four different nanocomposites: PLLA + CNT, PLLA + CNTHA, PLLA + CNT + HA + BMP2 and PLLA + CNT + HA + PT. Adult bone marrow mesenchymal stromal cells (MSCs) were derived from the femur of orthopaedic patients, seeded on the scaffolds and cultured under osteogenic induction up to differentiation and mineralization. The release of specific metabolites and temporal gene expression profiles of marrow-derived osteoprogenitors were analyzed at definite time points, relevant to in vitro culture as well as in vivo differentiation. As a result, the role of the different biomimetic components added to the PLLA matrix was deciphered, with BMP2-added scaffolds showing the highest biomimetic activity on cells differentiating to mature osteoblasts. The modification of a polymeric scaffold with reinforcing components which also work as biomimetic cues for cells can effectively direct osteoprogenitor cells differentiation, so as to shorten the time required for mineralization. PMID:22408463

  4. The development of a three-dimensional scaffold for ex vivo biomimicry of human acute myeloid leukaemia.

    PubMed

    Blanco, Teresa Mortera; Mantalaris, Athanasios; Bismarck, Alexander; Panoskaltsis, Nicki

    2010-03-01

    Acute myeloid leukaemia (AML) is a cancer of haematopoietic cells that develops in three-dimensional (3-D) bone marrow niches in vivo. The study of AML has been hampered by lack of appropriate ex vivo models that mimic this microenvironment. We hypothesised that fabrication and optimisation of suitable biomimetic scaffolds for culturing leukaemic cells ex vivo might facilitate the study of AML in its native 3-D niche. We evaluated the growth of three leukaemia subtype-specific cell lines, K-562, HL60 and Kasumi-6, on highly porous scaffolds fabricated from biodegradable and non-biodegradable polymeric materials, such as poly (L-lactic-co-glycolic acid) (PLGA), polyurethane (PU), poly (methyl-methacrylate), poly (D, L-lactade), poly (caprolactone), and polystyrene. Our results show that PLGA and PU supported the best seeding efficiency and leukaemic growth. Furthermore, the PLGA and PU scaffolds were coated with extracellular matrix (ECM) proteins, collagen type I (62.5 or 125 microg/ml) and fibronectin (25 or 50 microg/ml) to provide biorecognition signals. The 3 leukaemia subtype-specific lines grew best on PU scaffolds coated with 62.5 microg/ml collagen type I over 6 weeks in the absence of exogenous growth factors. In conclusion, PU-collagen scaffolds may provide a practical model to study the biology and treatment of primary AML in an ex vivo mimicry. PMID:20015543

  5. Method for making a bio-compatible scaffold

    DOEpatents

    Cesarano, III, Joseph (Albuquerque, NM); Stuecker, John N. (Albuquerque, NM); Dellinger, Jennifer G. (Champaigne, IL); Jamison, Russell D. (Urbana, IL)

    2006-01-31

    A method for forming a three-dimensional, biocompatible, porous scaffold structure using a solid freeform fabrication technique (referred to herein as robocasting) that can be used as a medical implant into a living organism, such as a human or other mammal. Imaging technology and analysis is first used to determine the three-dimensional design required for the medical implant, such as a bone implant or graft, fashioned as a three-dimensional, biocompatible scaffold structure. The robocasting technique is used to either directly produce the three-dimensional, porous scaffold structure or to produce an over-sized three-dimensional, porous scaffold lattice which can be machined to produce the designed three-dimensional, porous scaffold structure for implantation.

  6. Osteoinductive silk fibroin/titanium dioxide/hydroxyapatite hybrid scaffold for bone tissue engineering.

    PubMed

    Kim, Jung-Ho; Kim, Dong-Kyu; Lee, Ok Joo; Ju, Hyung Woo; Lee, Jung Min; Moon, Bo Mi; Park, Hyun Jung; Kim, Dong Wook; Lee, Jun Ho; Park, Chan Hum

    2016-01-01

    The present study demonstrated the fabrication that incorporation of titanium isopropoxide (TiO2) and hydroxyapatite (HA) nanoparticles into the silk fibroin (SF) scaffolds. In this process, we prepared TiO2 nanoparticles using sol-gel synthesis and the porous structure was developed by salt-leaching process. Homogeneous distribution of TiO2 and HA nanoparticles were confirmed by images of VP-FE-SEM and those equipped with energy dispersive X-ray spectrometer. Structural characteristics of the porous SF/TiO2/HA hybrid scaffold were also determined using FTIR analysis and X-ray diffractometer. In this study, the porous SF/TiO2/HA hybrid scaffold showed similar porosity, enhanced mechanical property, but decreased water binding abilities, compared with the porous SF scaffold. For evaluation of the osteogenic differentiation of rat bone marrow mesenchymal stem cells, alkaline phosphatase activity and osteogenic gene expression were employed. Our results revealed that the porous SF/TiO2/HA hybrid scaffold had improved osteoinductivity compared with the porous SF scaffold. These results suggest that the osteogenic property as well as mechanical property of the porous SF/TiO2/HA hybrid scaffold could be better than the porous SF scaffold. Therefore, the porous SF/TiO2/HA hybrid scaffold may be a good promising biomaterial for bone tissue engineering application. PMID:26257379

  7. The Crystallization Behavior of Porous PLA Prepared by Modified Solvent Casting/Particulate Leaching Technique for Potential Use of Tissue Engineering Scaffold

    E-print Network

    Ran Huang; Xiaomin Zhu; Haiyan Tu; Ajun Wan

    2014-04-14

    The porous PLA foams potential for tissue engineering usage are prepared by a modified solvent casting/particulate leaching method with different crystallinity. Since in typical method the porogens are solved in the solution and flow with the polymers during the casting and the crystallinity behavior of PLA chains in the limited space cannot be tracked, in this work the processing is modified by diffusing the PLA solution into a steady salt stack. With a thermal treatment before leaching while maintaining the stable structure of the porogens stack, the crystallinity of porous foams is made possible to control. The characterizations indicate the crystallization of porous foams is in a manner of lower crystallibility than the bulk materials. Pores and caves of around 250{\\mu}m size are obtained in samples with different crystallinity. The macro-structures are not much impaired by the crystallization nevertheless the morphological effect of the heating process is still obvious.

  8. Accelerated tissue integration into porous materials by immobilizing basic fibroblast growth factor using a biologically safe three-step reaction.

    PubMed

    Kakinoki, Sachiro; Sakai, Yusuke; Fujisato, Toshia; Yamaoka, Tetsuji

    2015-12-01

    Soft tissue integration into a porous structure is important to prevent bacterial infection of percutaneous devices and improve tissue regeneration using porous scaffolds. Here, basic fibroblast growth factor (bFGF) was immobilized on porous polymer materials using a mild and biologically safe three-step reaction: (1) modification with a novel surface-modification peptide (penta-lysine-mussel adhesive sequence, which reacts with various matrices), (2) electrostatic binding of heparin with introduced penta-lysine, and (3) biologically specific binding of bFGF to heparin. Porous polyethylene specimens (PPSs) (D = 6.0 mm, H?=?2.0 mm) with a good size for tissue integration were selected as a base material, immobilized with bFGF, and subcutaneously implanted into mice. Half of the unmodified PPSs extruded out of the body on day 112 postimplantation; however, the three-step reaction completely prevented sample rejection. Tissue integration was greatly accelerated by immobilizing bFGF. Direct physical coating of bFGF on PPS resulted in greater immobilization but lesser tissue integration than that after the three-step bFGF immobilization, indicating that heparin binds and enhances bFGF efficacy. This three-step bFGF immobilization reaction will be applicable to various polymeric, metallic, and ceramic materials and is a simple strategy to integrate tissue on porous medical devices or scaffolds for tissue regeneration. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3790-3797, 2015. PMID:26034014

  9. Evaluation of biodegradable elastic scaffolds made of anionic polyurethane for cartilage tissue engineering.

    PubMed

    Tsai, Meng-Chao; Hung, Kun-Che; Hung, Shih-Chieh; Hsu, Shan-hui

    2015-01-01

    Biodegradable polyurethane (PU) was synthesized by a water-based process. The process rendered homogenous PU nanoparticles (NPs). Spongy PU scaffolds in large dimensions were obtained by freeze-drying the PU NP dispersion. The spongy scaffolds were characterized in terms of the porous structure, wettability, mechanical properties, degradation behavior, and degradation products. The capacity as cartilage tissue engineering scaffolds was evaluated by growing chondrocytes and mesenchymal stem cells (MSCs) in the scaffolds. Scaffolds made from the PU dispersion had excellent hydrophilicity, porosity, and water absorption. Examination by micro-computed tomography confirmed that PU scaffolds had good pore interconnectivity. The degradation rate of the scaffolds in phosphate buffered saline was much faster than that in papain solution or in deionized water at 37°C. The biodegradable PU appeared to be degraded via the cleavage of ester linkage The intrinsic elastic property of PU and the gyroid-shape porous structure of the scaffolds may have accounted for the outstanding strain recovery (87%) and elongation behavior (257%) of the PU scaffolds, compared to conventional poly(d,l-lactide) (PLA) scaffolds. Chondrocytes were effectively seeded in PU scaffolds without pre-wetting. They grew better and secreted more glycosaminoglycan in PU scaffolds vs. PLA scaffolds. Human MSCs showed greater chondrogenic gene expression in PU scaffolds than in PLA scaffolds after induction. Based on the favorable hydrophilicity, elasticity, and regeneration capacities, the novel biodegradable PU scaffolds may be superior to the conventional biodegradable scaffolds in cartilage tissue engineering applications. PMID:25460599

  10. Scaffolding and Metacognition

    ERIC Educational Resources Information Center

    Holton, Derek; Clarke, David

    2006-01-01

    This paper proposes an expanded conception of scaffolding with four key elements: (1) scaffolding agency--expert, reciprocal, and self-scaffolding; (2) scaffolding domain--conceptual and heuristic scaffolding; (3) the identification of self-scaffolding with metacognition; and (4) the identification of six zones of scaffolding activity; each zone…

  11. Biocompatibility and biodegradation of polyester and polyfumarate based-scaffolds for bone tissue engineering.

    PubMed

    Cortizo, M Susana; Molinuevo, M Silvina; Cortizo, Ana M

    2008-01-01

    Biodegradable and biocompatible polymeric scaffolds have been recently introduced for tissue regeneration purpose. In the present study we aimed to develop polymeric-based scaffolds for bone regeneration. Two polyesters, poly-beta-propiolactone (PBPL), poly-epsilon-caprolactone (PCPL) and two polyfumarates, polydiisopropyl fumarate (PDIPF), polydicyclohexyl fumarate (PDCF) were chosen to prepare films which can support osteoblastic growth. Scanning electron microscopy and water contact angle were used to characterize the matrices. Biodegradation studies were performed both in PBS buffer and using an in vitro macrophage degradation assay. Mouse calvaria-derived MC3T3E1 cells and UMR106 rat osteosarcoma cell lines were used to perform biocompatibility and cytotoxicity studies. The polyesters, the most hydrophilic polymers studied, showed a rougher and more porous surfaces than the polyfumarates. Under acellular conditions, only PBPL was degraded by hydrolytic mechanisms. However, macrophages performed an active degradation of all polymeric films. Osteoblasts developed well-defined actin fibres without evidence of cytotoxicity when growing on the films. The number of UMR106 osteoblasts that adhered to the PBPL-based film was higher than that of the cells attached to the PECL and polyfumarates (PDIPF and PDCF) matrices. Both UMR106 and MC3T3E1 osteoblastic lines showed protein levels comparable to control conditions, demonstrating that they grew well on all surfaces. However, UMR106 cells showed a significant increase in proliferation on polyester-derived scaffolds (PBPL and PECL). The alkaline phosphatase activity of UMR106, an osteoblastic marker, was significantly higher than that of control plastic dishes. MC3T3E1 cells expressed similar levels of this differentiation marker in all polymeric matrices. We found similar collagen protein content after 48 h culture of UMR106 cells on all surfaces. However, important differences were evident in the MC3T3E1 line. In conclusion, the synthetic polymeric-based scaffold we have developed and studied supports adhesion, growth and differentiation of two osteoblastic cell lines, suggesting that they could be useful in bone tissue regeneration. PMID:18273918

  12. Effect of hydroxyapatite-containing microspheres embedded into three-dimensional magnesium phosphate scaffolds on the controlled release of lysozyme and in vitro biodegradation.

    PubMed

    Lee, Jongman; Yun, Hui-Suk

    2014-01-01

    The functionality of porous three-dimensional (3D) magnesium phosphate (MgP) scaffold was investigated for the development of a novel protein delivery system and biomimetic bone tissue engineering scaffold. This enhancement can be achieved by incorporation of hydroxyapatite (HA)-containing polymeric microspheres (MSs) into a bulk MgP matrix, and a paste-extruding deposition (PED) system. In this work, the amount of MS and HA was precisely controlled when manufacturing MS-embedded MgP (MS/MgP) composite scaffolds. The main influence was researched in terms of in vitro lysozyme-release, in vitro biodegradation, mechanical properties, and in vitro calcification. The controlled release of lysozyme was indicated, while showing graded release patterns according to HA content. The composite scaffolds degraded gradually with MS content and degradation time. Due to the effect of HA inclusion, the higher HA-containing MS/MgP scaffolds could, not only delay the biodegradation process but also, compensate for the possible loss of mechanical properties. In this regard, it is reasonable to confirm the inverse relationship between biodegradation and corresponding compressive properties. In order to encourage bioactivity and osteoconductivity, the MS/MgP composite scaffolds were subjected to simulated body fluid treatment. Calcium deposition was, in turn, improved with increasing MS and HA content over time. This quantitative result was also proved using morphological and elemental analysis. In summary, a significant transformation of a monolithic MgP scaffold was directed toward a multifunctional bone tissue engineering scaffold equipped with controlled protein delivery, biodegradability, and bioactivity. PMID:25214782

  13. Effect of hydroxyapatite-containing microspheres embedded into three-dimensional magnesium phosphate scaffolds on the controlled release of lysozyme and in vitro biodegradation

    PubMed Central

    Lee, Jongman; Yun, Hui-suk

    2014-01-01

    The functionality of porous three-dimensional (3D) magnesium phosphate (MgP) scaffold was investigated for the development of a novel protein delivery system and biomimetic bone tissue engineering scaffold. This enhancement can be achieved by incorporation of hydroxyapatite (HA)-containing polymeric microspheres (MSs) into a bulk MgP matrix, and a paste-extruding deposition (PED) system. In this work, the amount of MS and HA was precisely controlled when manufacturing MS-embedded MgP (MS/MgP) composite scaffolds. The main influence was researched in terms of in vitro lysozyme-release, in vitro biodegradation, mechanical properties, and in vitro calcification. The controlled release of lysozyme was indicated, while showing graded release patterns according to HA content. The composite scaffolds degraded gradually with MS content and degradation time. Due to the effect of HA inclusion, the higher HA-containing MS/MgP scaffolds could, not only delay the biodegradation process but also, compensate for the possible loss of mechanical properties. In this regard, it is reasonable to confirm the inverse relationship between biodegradation and corresponding compressive properties. In order to encourage bioactivity and osteoconductivity, the MS/MgP composite scaffolds were subjected to simulated body fluid treatment. Calcium deposition was, in turn, improved with increasing MS and HA content over time. This quantitative result was also proved using morphological and elemental analysis. In summary, a significant transformation of a monolithic MgP scaffold was directed toward a multifunctional bone tissue engineering scaffold equipped with controlled protein delivery, biodegradability, and bioactivity. PMID:25214782

  14. Composites for delivery of therapeutics: combining melt electrospun scaffolds with loaded electrosprayed microparticles.

    PubMed

    Bock, Nathalie; Woodruff, Maria A; Steck, Roland; Hutmacher, Dietmar W; Farrugia, Brooke L; Dargaville, Tim R

    2014-02-01

    A novel strategy is reported to produce biodegradable microfiber-scaffolds layered with high densities of microparticles encapsulating a model protein. Direct electrospraying on highly porous melt electrospun scaffolds provides a reproducible scaffold coating throughout the entire architecture. The burst release of protein is significantly reduced due to the immobilization of microparticles on the surface of the scaffold and release mechanisms are dependent on protein-polymer interactions. The composite scaffolds have a positive biological effect in contact with precursor osteoblast cells up to 18 days in culture. The scaffold design achieved with the techniques presented here endorses these new composite scaffolds as promising templates for growth factor delivery. PMID:24106032

  15. Development and characterization of a family of shape memory, biocompatible, degradable, porous (co)-polyurethanes via sol-gel chemistry

    NASA Astrophysics Data System (ADS)

    Lippincott, Hugh Walker

    In support of the goal of a tissue engineering scaffold that is moldable, biodegradable and has shape-memory, this work explored the space of polyurethane sol-gel formulations and solvents to create a biocompatible, porous xerogel with potential to be such a porous scaffold. The work has resulted in both a process and a sol-gel formulation to effectively create a family of degradable, biocompatible, shape memory, porous, block copolyurethane xerogels from polycaprolactone and castor oil. Formulations of the sol-gel family of potential scaffolds were characterized for their biocompatibility, hydrolytic degradability, porosity, and shape memory. Of the scaffolds tested in this fashion, the most successful supported the attachment and growth of 3T3 fibroblast cells at 72% of the rate of attachment and growth in the standard tissue culture plastic Petri dishes. A method was developed and explained that selects the solvent for creation of a porous xerogel by controlling the phase separation of the polymerizing polyurethane from the reaction solution. This method uses standard polymer solvent swelling and extraction test data. Solvent solutions plotted in the 3-D space of Hansen solubility parameters were used to select solvents that produced porous xerogels from two different polyurethane sol-gel formulations. The process effectively combines a set of methods that search the sol-gel formulation spaces for both shape-memory and porosity. Easily produced dense xerogels from trial sol-gel formulations are sufficient for DSC and initial DMA shape-memory test data, as well as standard solvent swelling and extraction test data to support the search for shape memory and the computation of rankings to select solvent(s) that is most likely to produce a porous xerogel. Accelerated degradation tests on the dense xerogels also produced results useful to guide further testing of the sol-gel formulations. Standard shape-memory research testing only characterizes the free return to shape or the shape memory force with no return from a tensile test. Characterization of the scaffold's compressive shape memory (percent strain recovery under stress) offers a clinical user design data for interactions with body tissue. Standard tensile shape memory ratios were translated to the compressive stress, strain, and temperature cycles used to characterize the shape-memory abilities of the two sol-gel families tested. The advantage of a thermoset polymer's ability to achieve 100% shape memory repeatability is demonstrated. This scaffold's compressive shape memory actuation energy density was above 6.0 KJ/m 3 over a range of recovery strains from 5% to 12%.

  16. Nanostructured Polymers Prepared Using a Self-Assembled Nanofibrillar Scaffold as a Reverse Template

    E-print Network

    Raghavan, Srinivasa

    Nanostructured Polymers Prepared Using a Self-Assembled Nanofibrillar Scaffold as a Reverse describe the preparation of nanostructured polymeric materials by polymerizing a monomer within a scaffold composed of self-assembled nanofibrils. 1,3:2,4-Dibenzylidene sorbitol (DBS) is an inexpensive sugar

  17. Nanofibrous Scaffolds for Dental and Craniofacial Applications

    PubMed Central

    Gupte, M.J.; Ma, P.X.

    2012-01-01

    Tissue-engineering solutions often harness biomimetic materials to support cells for functional tissue regeneration. Three-dimensional scaffolds can create a multi-scale environment capable of facilitating cell adhesion, proliferation, and differentiation. One such multi-scale scaffold incorporates nanofibrous features to mimic the extracellular matrix along with a porous network for the regeneration of a variety of tissues. This review will discuss nanofibrous scaffold synthesis/fabrication, biological effects of nanofibers, their tissue- engineering applications in bone, cartilage, enamel, dentin, and periodontium, patient-specific scaffolds, and incorporated growth factor delivery systems. Nanofibrous scaffolds cannot only further the field of craniofacial regeneration but also advance technology for tissue-engineered replacements in many physiological systems. PMID:21828356

  18. Fabrication of Mechanically Tunable and Bioactive Metal Scaffolds for Biomedical Applications.

    PubMed

    Jung, Hyun-Do; Lee, Hyun; Kim, Hyoun-Ee; Koh, Young-Hag; Song, Juha

    2015-01-01

    Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness and low bioactivity of metals. In this study, we have developed a new method towards fabricating a new type of bioactive and mechanically reliable porous metal scaffolds-densified porous Ti scaffolds. The method consists of two fabrication processes, 1) the fabrication of porous Ti scaffolds by dynamic freeze casting, and 2) coating and densification of the porous scaffolds. The dynamic freeze casting method to fabricate porous Ti scaffolds allowed the densification of porous scaffolds by minimizing the chemical contamination and structural defects. The densification process is distinctive for three reasons. First, the densification process is simple, because it requires a control of only one parameter (degree of densification). Second, it is effective, as it achieves mechanical enhancement and sustainable release of biomolecules from porous scaffolds. Third, it has broad applications, as it is also applicable to the fabrication of functionally graded porous scaffolds by spatially varied strain during densification. PMID:26709604

  19. Tissue growth into three-dimensional composite scaffolds with controlled micro-features and nanotopographical surfaces.

    PubMed

    Tamjid, Elnaz; Simchi, Arash; Dunlop, John W C; Fratzl, Peter; Bagheri, Reza; Vossoughi, Manouchehr

    2013-10-01

    Controlling topographic features at all length scales is of great importance for the interaction of cells with tissue regenerative materials. We utilized an indirect three-dimensional printing method to fabricate polymeric scaffolds with pre-defined and controlled external and internal architecture that had an interconnected structure with macro- (400-500 ?m) and micro- (?25 ?m) porosity. Polycaprolactone (PCL) was used as model system to study the kinetics of tissue growth within porous scaffolds. The surface of the scaffolds was decorated with TiO2 and bioactive glass (BG) nanoparticles to the better match to nanoarchitecture of extracellular matrix (ECM). Micrometric BG particles were also used to reveal the effect of particle size on the cell behavior. Observation of tissue growth and enzyme activity on two-dimensional (2D) films and three-dimensional (3D) scaffolds showed effects of nanoparticle inclusion and of surface curvature on the cellular adhesion, proliferation, and kinetics of preosteoblastic cells (MC3T3-E1) tissue growth into the pore channels. It was found that the presence of nanoparticles in the substrate impaired cellular adhesion and proliferation in 3D structures. Evaluation of alkaline phosphate activity showed that the presence of the hard particles affects differentiation of the cells on 2D films. Notwithstanding, the effect of particles on cell differentiation was not as strong as that seen by the curvature of the substrate. We observed different effects of nanofeatures on 2D structures with those of 3D scaffolds, which influence the cell proliferation and differentiation for non-load-bearing applications in bone regenerative medicine. PMID:23463703

  20. ECM Inspired Coating of Embroidered 3D Scaffolds Enhances Calvaria Bone Regeneration

    PubMed Central

    Rentsch, C.; Rentsch, B.; Heinemann, S.; Bernhardt, R.; Bischoff, B.; Förster, Y.; Scharnweber, D.; Rammelt, S.

    2014-01-01

    Resorbable polymeric implants and surface coatings are an emerging technology to treat bone defects and increase bone formation. This approach is of special interest in anatomical regions like the calvaria since adults lose the capacity to heal large calvarial defects. The present study assesses the potential of extracellular matrix inspired, embroidered polycaprolactone-co-lactide (PCL) scaffolds for the treatment of 13?mm full thickness calvarial bone defects in rabbits. Moreover the influence of a collagen/chondroitin sulfate (coll I/cs) coating of PCL scaffolds was evaluated. Defect areas filled with autologous bone and empty defects served as reference. The healing process was monitored over 6 months by combining a novel ultrasonographic method, radiographic imaging, biomechanical testing, and histology. The PCL coll I/cs treated group reached 68% new bone volume compared to the autologous group (100%) and the biomechanical stability of the defect area was similar to that of the gold standard. Histological investigations revealed a significantly more homogenous bone distribution over the whole defect area in the PCL coll I/cs group compared to the noncoated group. The bioactive, coll I/cs coated, highly porous, 3-dimensional PCL scaffold acted as a guide rail for new skull bone formation along and into the implant. PMID:25013767

  1. Sol-gel derived bioactive glasses with low tendency to crystallize: synthesis, post-sintering bioactivity and possible application for the production of porous scaffolds.

    PubMed

    Bellucci, Devis; Sola, Antonella; Salvatori, Roberta; Anesi, Alexandre; Chiarini, Luigi; Cannillo, Valeria

    2014-10-01

    A new sol-gel (SG) method is proposed to produce special bioactive glasses (BG_Ca family) characterized by a low tendency to devitrify. These formulations, derived from 45S5 Bioglass®, are characterized by a high content of CaO (45.6 mol%) and by a partial or complete substitution of sodium oxide with potassium oxide (total amount of alkaline oxides: 4.6 mol%), which increases the crystallization temperature up to 900°C. In this way, it is possible to produce them by SG preserving their amorphous nature, in spite of the calcination at 850°C. The sintering behavior of the obtained SG powders is thoroughly investigated and the properties of the sintered bodies are compared to those of the melt-derived (M) counterparts. Furthermore, the SG glass powders are successfully used to produce scaffolds by means of a modified replication technique based on the combined use of polyurethane sponges and polyethylene particles. Finally, in the view of a potential application for bone tissue engineering, the cytotoxicity of the produced materials is evaluated in vitro. PMID:25175252

  2. Preparation and characterization of bionic bone structure chitosan/hydroxyapatite scaffold for bone tissue engineering.

    PubMed

    Zhang, Jiazhen; Nie, Jingyi; Zhang, Qirong; Li, Youliang; Wang, Zhengke; Hu, Qiaoling

    2014-01-01

    Three-dimensional oriented chitosan (CS)/hydroxyapatite (HA) scaffolds were prepared via in situ precipitation method in this research. Scanning electron microscopy (SEM) images indicated that the scaffolds with acicular nano-HA had the spoke-like, multilayer and porous structure. The SEM of osteoblasts which were polygonal or spindle-shaped on the composite scaffolds after seven-day cell culture showed that the cells grew, adhered, and spread well. The results of X-ray powder diffractometer and Fourier transform infrared spectrometer showed that the mineral particles deposited in the scaffold had phase structure similar to natural bone and confirmed that particles were exactly HA. In vitro biocompatibility evaluation indicated the composite scaffolds showed a higher degree of proliferation of MC3T3-E1 cell compared with the pure CS scaffolds and the CS/HA10 scaffold was the highest one. The CS/HA scaffold also had a higher ratio of adhesion and alkaline phosphate activity value of osteoblasts compared with the pure CS scaffold, and the ratio increased with the increase of HA content. The ALP activity value of composite scaffolds was at least six times of the pure CS scaffolds. The results suggested that the composite scaffolds possessed good biocompatibility. The compressive strength of CS/HA15 increased by 33.07% compared with the pure CS scaffold. This novel porous scaffold with three-dimensional oriented structure might have a potential application in bone tissue engineering. PMID:24053536

  3. Bone Tissue Engineering by Using Calcium Phosphate Glass Scaffolds and the Avidin-Biotin Binding System.

    PubMed

    Kim, Min-Chul; Hong, Min-Ho; Lee, Byung-Hyun; Choi, Heon-Jin; Ko, Yeong-Mu; Lee, Yong-Keun

    2015-12-01

    Highly porous and interconnected scaffolds were fabricated using calcium phosphate glass (CPG) for bone tissue engineering. An avidin-biotin binding system was used to improve osteoblast-like cell adhesion to the scaffold. The scaffolds had open macro- and micro-scale pores, and continuous struts without cracks or defects. Scaffolds prepared using a mixture (amorphous and crystalline CPG) were stronger than amorphous group and crystalline group. Cell adhesion assays showed that more cells adhered, with increasing cell seeding efficiency to the avidin-adsorbed scaffolds, and that cell attachment to the highly porous scaffolds significantly differed between avidin-adsorbed scaffolds and other scaffolds. Proliferation was also significantly higher for avidin-adsorbed scaffolds. Osteoblastic differentiation of MG-63 cells was observed at 3 days, and MG-63 cells in direct contact with avidin-adsorbed scaffolds were positive for type I collagen, osteopontin, and alkaline phosphatase gene expression. Osteocalcin expression was observed in the avidin-adsorbed scaffolds at 7 days, indicating that cell differentiation in avidin-adsorbed scaffolds occurred faster than the other scaffolds. Thus, these CPG scaffolds have excellent biological properties suitable for use in bone tissue engineering. PMID:26040755

  4. In Vitro and In Vivo Characterization of Pentaerythritol Triacrylate-co-Trimethylolpropane Nanocomposite Scaffolds as Potential Bone Augments and Grafts

    PubMed Central

    Chen, Cong; Garber, Leah; Smoak, Mollie; Fargason, Carmel; Scherr, Thomas; Blackburn, Caleb; Bacchus, Sasha; Lopez, Mandi J.; Pojman, John A.; Del Piero, Fabio

    2015-01-01

    A thiol-acrylate-based copolymer synthesized via an amine-catalyzed Michael addition was studied in vitro and in vivo to assess its potential as an in situ polymerizing graft or augment in bone defect repair. The blends of hydroxyapatite (HA) with pentaerythritol triacrylate-co-trimethylolpropane (PETA), cast as solids or gas foamed as porous scaffolds, were evaluated in an effort to create a biodegradable osteogenic material for use as a bone-void-filling augment. Osteogenesis experiments were conducted with human adipose-derived mesenchymal stromal cells (hASCs) to determine the ability of the material to serve as an osteoinductive substrate. Poly(?-caprolactone) (PCL) composites PCL:HA (80:20) (wt/wt%) served as the control scaffold, while the experimental scaffolds included PETA:HA (100:0), (85:15), (80:20), and (75:25) composites (wt/wt%). The results indicate that PETA:HA (80:20) foam composites had higher mechanical strength than the corresponding porous PCL:HA (80:20) scaffolds made by thermo-precipitation method, and in the case of foamed composites, increasing HA content directly correlated with increased yield strength. For cytotoxicity and osteogenesis experiments, hASCs cultured for 21 days on PETA:HA scaffolds in stromal medium displayed the greatest number of live cells compared with PCL:HA composites. Moreover, hASCs cultured on foamed PETA:HA (80:20) scaffolds resulted in the greatest mineralization, increased alkaline phosphatase (ALP) expression, and the highest osteocalcin (OCN) expression after 21 days. Overall, the PETA:HA (80:20) and PETA:HA (85:15) scaffolds, with 66.38% and 72.02% porosity, respectively, had higher mechanical strength and cytocompatibility compared with the PCL:HA control. The results of the 6-week in vivo biocompatibility study using a posterior lumbar spinal fusion model demonstrate that PETA:HA can be foamed in vivo without serious adverse effects at the surgical site. Additionally, it was demonstrated that cells migrate into the interconnected pore volume and are found within centers of ossification. PMID:25134965

  5. Variation of flow-induced stresses within scaffolds used in bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Papavassiliou, Dimitrios; Pham, Ngoc; Voronov, Roman; Sikavitsas, Vassilios

    2011-11-01

    Bone tissue engineering is often based on seeding adult stem cells on porous scaffolds and subsequently placing these scaffolds in flow perfusion bioreactors to stimulate cell differentiation and cell growth. In the present study, the distribution of stresses in structured porous scaffolds under flow is investigated by calculating the probability density function of flow-induced stresses in different scaffold geometries with simulations. The physical reason for the development of particular stress distributions is further explored, and it is found that the direction of flow relative to the internal architecture of the porous scaffold is important for stress distributions. When the flow direction is random relative to the configuration of the geometric elements making up the scaffold, it is found that a common distribution, such as the one suggested by Voronov et al. (Appl. Phys. Let., 2010, 97:024101), can be used to describe the stress distribution. NSF CBET-070081.

  6. Fabrication of polylactide nanocomposite scaffolds for bone tissue engineering applications

    SciTech Connect

    Mkhabela, Vuyiswa J.; Ray, Suprakas Sinha

    2015-05-22

    Highly porous three-dimensional polylactide (PLA) scaffolds were obtained from PLA incorporated with different amounts of chitosan-modified montmorillonite (CS-MMT), through solvent casting and particulate leaching method. The processed scaffolds were tested in vitro for their possible application in bone tissue engineering. Scaffolds were characterized by Focused Ion Beam Scanning Electron Microscopy (FIB SEM), Fourier Transform Infra-Red (FTIR), and X-Ray Diffraction (XRD) to study their structure and intermolecular interactions. Bioresorbability tests in simulated body fluid (pH 7.4) were conducted to assess the response of the scaffolds in a simulated physiological condition. The FIB SEM images of the scaffolds showed a porous architecture with gradual change in morphology with increasing CS-MMT concentration. FTIR analysis revealed the presence of both PLA and CS-MMT particles on the surface of the scaffolds. XRD showed that the crystalline unit cell type was the same for all the scaffolds, and crystallinity decreased with an increase in CS-MMT concentration. The scaffolds were found to be bioresorbable, with rapid bioresorbability on the scaffolds with a high CS-MMT concentration.

  7. Fabrication of polylactide nanocomposite scaffolds for bone tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Mkhabela, Vuyiswa J.; Ray, Suprakas Sinha

    2015-05-01

    Highly porous three-dimensional polylactide (PLA) scaffolds were obtained from PLA incorporated with different amounts of chitosan-modified montmorillonite (CS-MMT), through solvent casting and particulate leaching method. The processed scaffolds were tested in vitro for their possible application in bone tissue engineering. Scaffolds were characterized by Focused Ion Beam Scanning Electron Microscopy (FIB SEM), Fourier Transform Infra-Red (FTIR), and X-Ray Diffraction (XRD) to study their structure and intermolecular interactions. Bioresorbability tests in simulated body fluid (pH 7.4) were conducted to assess the response of the scaffolds in a simulated physiological condition. The FIB SEM images of the scaffolds showed a porous architecture with gradual change in morphology with increasing CS-MMT concentration. FTIR analysis revealed the presence of both PLA and CS-MMT particles on the surface of the scaffolds. XRD showed that the crystalline unit cell type was the same for all the scaffolds, and crystallinity decreased with an increase in CS-MMT concentration. The scaffolds were found to be bioresorbable, with rapid bioresorbability on the scaffolds with a high CS-MMT concentration.

  8. Cytocompatibility and osteogenesis evaluation of HA/GCPU composite as scaffolds for bone tissue engineering.

    PubMed

    Du, Jingjing; Zou, Qin; Zuo, Yi; Li, Yubao

    2014-01-01

    Porous scaffolds for bone repair were prepared from newly designed segmented aliphatic polyurethane based on glyceride of castor oil and isophorone diisocyanate. To promote the scaffolds' biological and mechanical properties, hydroxyapatite powder was incorporated into the polymer matrix. The scaffold (named as HA/GCPU) with 40 wt% HA had an average pore size of 500 ?m and a compressive strength of 4.6 MPa. The in vitro cell culture studies demonstrated that the HA/GCPU scaffold owned good cytocompatibility. The scaffold and cell-seeded scaffold were implanted in defects (?3 mm × 3 mm) of femoral condyle of Sprague-Dawley rats, respectively. New bone could extensively form in both the scaffold and cell-seeded scaffold. It indicates that the HA/GCPU composite scaffold has good prospect for bone repair and regeneration. PMID:24657710

  9. Chitosan-based scaffolds for bone tissue engineering

    PubMed Central

    Levengood, Sheeny Lan; Zhang, Miqin

    2014-01-01

    Bone defects requiring grafts to promote healing are frequently occurring and costly problems in health care. Chitosan, a biodegradable, naturally occurring polymer, has drawn considerable attention in recent years as scaffolding material in tissue engineering and regenerative medicine. Chitosan is especially attractive as a bone scaffold material because it supports the attachment and proliferation of osteoblast cells as well as formation of mineralized bone matrix. In this review, we discuss the fundamentals of bone tissue engineering and the unique properties of chitosan as a scaffolding material to treat bone defects for hard tissue regeneration. We present the common methods for fabrication and characterization of chitosan scaffolds, and discuss the influence of material preparation and addition of polymeric or ceramic components or biomolecules on chitosan scaffold properties such as mechanical strength, structural integrity, and functional bone regeneration. Finally, we highlight recent advances in development of chitosan-based scaffolds with enhanced bone regeneration capability. PMID:24999429

  10. Polymeric microspheres

    DOEpatents

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  11. Indirect additive manufacturing as an elegant tool for the production of self-supporting low density gelatin scaffolds.

    PubMed

    Van Hoorick, Jasper; Declercq, Heidi; De Muynck, Amelie; Houben, Annemie; Van Hoorebeke, Luc; Cornelissen, Ria; Van Erps, Jürgen; Thienpont, Hugo; Dubruel, Peter; Van Vlierberghe, Sandra

    2015-10-01

    The present work describes for the first time the production of self-supporting low gelatin density (<10 w/v%) porous scaffolds using methacrylamide-modified gelatin as an extracellular matrix mimicking component. As porous scaffolds starting from low gelatin concentrations cannot be realized with the conventional additive manufacturing techniques in the abscence of additives, we applied an indirect fused deposition modelling approach. To realize this, we have printed a sacrificial polyester scaffold which supported the hydrogel material during UV crosslinking, thereby preventing hydrogel structure collapse. After complete curing, the polyester scaffold was selectively dissolved leaving behind a porous, interconnective low density gelatin scaffold. Scaffold structural analysis indicated the success of the selected indirect additive manufacturing approach. Physico-chemical testing revealed scaffold properties (mechanical, degradation, swelling) to depend on the applied gelatin concentration and methacrylamide content. Preliminary biocompatibility studies revealed the cell-interactive and biocompatible properties of the materials developed. PMID:26411443

  12. Hierarchical Structure and Mechanical Improvement of an n-HA/GCO-PU Composite Scaffold for Bone Regeneration.

    PubMed

    Li, Limei; Zuo, Yi; Zou, Qin; Yang, Boyuan; Lin, Lili; Li, Jidong; Li, Yubao

    2015-10-14

    To improve the mechanical properties of bone tissue and achieve the desired bone tissue regeneration for orthopedic surgery, newly designed hydroxyapatite/polyurethane (HA/PU) porous scaffolds were developed via in situ polymerization. The results showed that the molecular modification of PU soft segments by glyceride of castor oil (GCO) can increase the scaffold compressive strength by 48% and the elastic modulus by 96%. When nano-HA (n-HA) particles were incorporated into the GCO-PU matrix, the compressive strength and elastic modulus further increased by 49 and 74%, from 2.91 to 4.34 MPa and from 95 to 165.36 MPa, respectively. The n-HA particles with fine dispersity not only improved the interface bonding with the GCO-PU matrix but also provided effective bioactivity for bonding with bone tissue. The hierarchical structure and mechanical quality of the n-HA/GCO-PU composite scaffold were determined to be appropriate for the growth of cells and the regeneration of bony tissues, demonstrating promising prospects for bone repair and regeneration. PMID:26406396

  13. Electrospun poly(d/l-lactide-co-l-lactide) hybrid matrix: a novel scaffold material for soft tissue engineering

    PubMed Central

    Kluger, Petra J.; Wyrwa, Ralf; Weisser, Jürgen; Maierle, Julia; Votteler, Miriam; Rode, Claudia; Schnabelrauch, Matthias; Walles, Heike

    2010-01-01

    Electrospinning is a long-known polymer processing technique that has received more interest and attention in recent years due to its versatility and potential use in the field of biomedical research. The fabrication of three-dimensional (3D) electrospun matrices for drug delivery and tissue engineering is of particular interest. In the present study, we identified optimal conditions to generate novel electrospun polymeric scaffolds composed of poly-d/l-lactide and poly-l-lactide in the ratio 50:50. Scanning electron microscopic analyses revealed that the generated poly(d/l-lactide-co-l-lactide) electrospun hybrid microfibers possessed a unique porous high surface area mimicking native extracellular matrix (ECM). To assess cytocompatibility, we isolated dermal fibroblasts from human skin biopsies. After 5 days of in vitro culture, the fibroblasts adhered, migrated and proliferated on the newly created 3D scaffolds. Our data demonstrate the applicability of electrospun poly(d/l-lactide-co-l-lactide) scaffolds to serve as substrates for regenerative medicine applications with special focus on skin tissue engineering. PMID:20640490

  14. Porosity and Cell Preseeding Influence Electrospun Scaffold Maturation and Meniscus Integration In Vitro

    PubMed Central

    Ionescu, Lara C.

    2013-01-01

    Electrospinning generates fibrous scaffolds ideal for engineering soft orthopedic tissues. By modifying the electrospinning process, scaffolds with different structural organization and content can be generated. For example, fibers can be aligned in a single direction, or the porosity of the scaffold can be modified through the use of multi-jet electrospinning and the removal of sacrificial fibers. In this work, we investigated the role of fiber alignment and scaffold porosity on construct maturation and integration within in vitro meniscus defects. Further, we explored the effect of preseeding expanded meniscus fibrochondrocytes (MFCs) onto the scaffold at a high density before in vitro repair. Our results demonstrate that highly porous electropun scaffolds integrate better with a native tissue and mature to a greater extent than low-porosity scaffolds, while scaffold alignment does not influence integration or maturation. The addition of expanded MFCs to scaffolds before in vitro repair improved integration with the native tissue, but did not influence maturation. In contrast, preculture of these same scaffolds for 1 month before repair decreased integration with the native tissue, but resulted in a more mature scaffold compared to implantation of cellular scaffolds or acellular scaffolds. This work will inform scaffold selection in future in vivo studies by identifying the ideal scaffold and seeding methods for meniscus tissue engineering. PMID:22994398

  15. Mineralization Potential of Electrospun PDO-Hydroxyapatite-Fibrinogen Blended Scaffolds

    PubMed Central

    Rodriguez, Isaac A.; Madurantakam, Parthasarathy A.; McCool, Jennifer M.; Sell, Scott A.; Yang, Hu; Moon, Peter C.; Bowlin, Gary L.

    2012-01-01

    The current bone autograft procedure for cleft palate repair presents several disadvantages such as limited availability, additional invasive surgery, and donor site morbidity. The present preliminary study evaluates the mineralization potential of electrospun polydioxanone:nano-hydroxyapatite?:?fibrinogen (PDO?:?nHA?:?Fg) blended scaffolds in different simulated body fluids (SBF). Scaffolds were fabricated by blending PDO?:?nHA?:?Fg in the following percent by weight ratios: 100?:?0?:?0, 50?:?25?:?25, 50?:?50?:?0, 50?:?0?:?50, 0?:?0?:?100, and 0?:?50?:?50. Samples were immersed in (conventional (c), revised (r), ionic (i), and modified (m)) SBF for 5 and 14 days to induce mineralization. Scaffolds were characterized before and after mineralization via scanning electron microscopy, Alizarin Red-based assay, and modified burnout test. The addition of Fg resulted in scaffolds with smaller fiber diameters. Fg containing scaffolds also induced sheet-like mineralization while individual fiber mineralization was noticed in its absence. Mineralized electrospun Fg scaffolds without PDO were not mechanically stable after 5 days in SBF, but had superior mineralization capabilities which produced a thick bone-like mineral (BLM) layer throughout the scaffolds. 50?:?50?:?0 scaffolds incubated in either r-SBF for 5 days or c-SBF for 14 days produced scaffolds with high mineral content and individual-mineralized fibers. These mineralized scaffolds were still porous and will be further optimized as an effective bone substitute in future studies. PMID:22956956

  16. Mineralization Potential of Electrospun PDO-Hydroxyapatite-Fibrinogen Blended Scaffolds.

    PubMed

    Rodriguez, Isaac A; Madurantakam, Parthasarathy A; McCool, Jennifer M; Sell, Scott A; Yang, Hu; Moon, Peter C; Bowlin, Gary L

    2012-01-01

    The current bone autograft procedure for cleft palate repair presents several disadvantages such as limited availability, additional invasive surgery, and donor site morbidity. The present preliminary study evaluates the mineralization potential of electrospun polydioxanone:nano-hydroxyapatite?:?fibrinogen (PDO?:?nHA?:?Fg) blended scaffolds in different simulated body fluids (SBF). Scaffolds were fabricated by blending PDO?:?nHA?:?Fg in the following percent by weight ratios: 100?:?0?:?0, 50?:?25?:?25, 50?:?50?:?0, 50?:?0?:?50, 0?:?0?:?100, and 0?:?50?:?50. Samples were immersed in (conventional (c), revised (r), ionic (i), and modified (m)) SBF for 5 and 14 days to induce mineralization. Scaffolds were characterized before and after mineralization via scanning electron microscopy, Alizarin Red-based assay, and modified burnout test. The addition of Fg resulted in scaffolds with smaller fiber diameters. Fg containing scaffolds also induced sheet-like mineralization while individual fiber mineralization was noticed in its absence. Mineralized electrospun Fg scaffolds without PDO were not mechanically stable after 5 days in SBF, but had superior mineralization capabilities which produced a thick bone-like mineral (BLM) layer throughout the scaffolds. 50?:?50?:?0 scaffolds incubated in either r-SBF for 5 days or c-SBF for 14 days produced scaffolds with high mineral content and individual-mineralized fibers. These mineralized scaffolds were still porous and will be further optimized as an effective bone substitute in future studies. PMID:22956956

  17. Soy Protein Scaffold Biomaterials for Tissue Engineering and Regenerative Medicine

    NASA Astrophysics Data System (ADS)

    Chien, Karen B.

    Developing functional biomaterials using highly processable materials with tailorable physical and bioactive properties is an ongoing challenge in tissue engineering. Soy protein is an abundant, natural resource with potential use for regenerative medicine applications. Preliminary studies show that soy protein can be physically modified and fabricated into various biocompatible constructs. However, optimized soy protein structures for tissue regeneration (i.e. 3D porous scaffolds) have not yet been designed. Furthermore, little work has established the in vivo biocompatibility of implanted soy protein and the benefit of using soy over other proteins including FDA-approved bovine collagen. In this work, freeze-drying and 3D printing fabrication processes were developed using commercially available soy protein to create porous scaffolds that improve cell growth and infiltration compared to other soy biomaterials previously reported. Characterization of scaffold structure, porosity, and mechanical/degradation properties was performed. In addition, the behavior of human mesenchymal stem cells seeded on various designed soy scaffolds was analyzed. Biological characterization of the cell-seeded scaffolds was performed to assess feasibility for use in liver tissue regeneration. The acute and humoral response of soy scaffolds implanted in an in vivo mouse subcutaneous model was also investigated. All fabricated soy scaffolds were modified using thermal, chemical, and enzymatic crosslinking to change properties and cell growth behavior. 3D printing allowed for control of scaffold pore size and geometry. Scaffold structure, porosity, and degradation rate significantly altered the in vivo response. Freeze-dried soy scaffolds had similar biocompatibility as freeze-dried collagen scaffolds of the same protein content. However, the soy scaffolds degraded at a much faster rate, minimizing immunogenicity. Interestingly, subcutaneously implanted soy scaffolds affected blood glucose and insulin sensitivity levels. Furthermore, soy scaffolds implanted in the intraperitoneal cavity attached to adjacent liver tissue with no abnormalities. In vitro, soy scaffolds supported hMSC viability and transdifferentiation into hepatocyte-like cells. These results support the use of soy scaffolds for liver tissue engineering and for treating metabolic diseases. Based on achievable structural and mechanical properties, as well as systemic effects of ingested and degraded soy proteins, soy protein scaffolds may serve as new multifunctional biomaterials for tissue engineering and regenerative medicine.

  18. Growth Factor Gradients via Microsphere Delivery in Biopolymer Scaffolds for Osteochondral Tissue Engineering

    PubMed Central

    Wang, Xiaoqin; Wenk, Esther; Zhang, Xiaohui; Meinel, Lorenz; Vunjak-Novakovic, Gordana; Kaplan, David L.

    2009-01-01

    Temporally and spatially controlled delivery of growth factors in polymeric scaffolds is crucial for engineering composite tissue structures, such as osteochondral constructs. In the present study, microsphere-mediated growth factor delivery in polymer scaffolds and its impact on osteochondral differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) was evaluated. Two growth factors, bone morphogenetic protein 2 (rhBMP-2) and insulin-like growth factor I (rhIGF-I), were incorporated as a single concentration gradient or reverse gradient combining two factors in the scaffolds. To assess the gradient making system and the delivery efficiency of polylactic-co-glycolic acid (PLGA) and silk fibroin microspheres, initially an alginate gel was fabricated into a cylinder shape with microspheres incorporated as gradients. Compared to PLGA microspheres, silk microspheres were more efficient in delivering rhBMP-2, probably due to sustained release of the growth factor, while less efficient in delivering rhIGF-I, likely due to loading efficiency. The growth factor gradients formed were shallow, inducing non-gradient trends in hMSC osteochondral differentiation. Aqueous-derived silk porous scaffolds were used to incorporate silk microspheres using the same gradient process. Both growth factors formed deep and linear concentration gradients in the scaffold, as shown by enzyme-linked immunosorbent assay (ELISA). After seeding with hMSCs and culturing for 5 weeks in a medium containing osteogenic and chondrogenic components, hMSCs exhibited osteogenic and chondrogenic differentiation along the concentration gradients of rhBMP-2 in the single gradient of rhBMP-2 and reverse gradient of rhBMP-2/rhIGF-I, but not the rhIGF-I gradient system, confirming that silk microspheres were more efficient in delivering rhBMP-2 than rhIGF-I for hMSCs osteochondrogenesis. This novel silk microsphere/scaffold system offers a new option for the delivery of multiple growth factors with spatial control in a 3D culture environment for both understanding natural tissue growth process and in vitro engineering complex tissue constructs. PMID:19071168

  19. Preparation and chemical and biological characterization of a pectin/chitosan polyelectrolyte complex scaffold for possible bone tissue engineering applications.

    PubMed

    Coimbra, P; Ferreira, P; de Sousa, H C; Batista, P; Rodrigues, M A; Correia, I J; Gil, M H

    2011-01-01

    In this work, porous scaffolds obtained from the freeze-drying of pectin/chitosan polyelectrolyte complexes were prepared and characterized by FTIR, SEM and weight loss studies. Additionally, the cytotoxicity of the prepared scaffolds was evaluated in vitro, using human osteoblast cells. The results obtained showed that cells adhered to scaffolds and proliferated. The study also confirmed that the degradation by-products of pectin/chitosan scaffold are noncytotoxic. PMID:20955729

  20. Investigation of potential injectable polymeric biomaterials for bone regeneration

    PubMed Central

    Dreifke, Michael B.; Ebraheim, Nabil A.; Jayasuriya, Ambalangodage C.

    2014-01-01

    This article reviews the potential injectable polymeric biomaterial scaffolds currently being investigated for application in bone tissue regeneration. Two types of injectable biomaterial scaffolds are focused in this review, including injectable microspheres and injectable gels. The injectable microspheres section covers several polymeric materials, including poly(l-lactide-co-glycolide)-PLGA, poly (propylene fumarate), and chitosan. The injectable gel section covers alginate gels, hyaluronan hydrogels, poly(ethylene-glycol)-PEG hydrogels, and PEG-PLGA copolymer hydrogels. This review focuses on the effect of cellular behaviorin vitro andin vivo in terms of material properties of polymers, such as biodegradation, biocompatibility, porosity, microsphere size, and cross-linking nature. Injectable polymeric biomaterials offer a major advantage for orthopedic applications by allowing the ability to use noninvasive or minimally invasive treatment methods. Therefore, combining injectable polymeric biomaterial scaffolds with cells have a significant potential to treat orthopedic bone defects, including spine fusion, and craniofacial and periodontal defects. PMID:23401336

  1. Premixed macroporous calcium phosphate cement scaffold

    PubMed Central

    Carey, Lisa E.; Simon, Carl G.

    2009-01-01

    Calcium phosphate cement (CPC) sets in situ to form resorbable hydroxyapatite and is promising for orthopaedic applications. However, it requires on-site powder-liquid mixing during surgery, which prolongs surgical time and raises concerns of inhomogeneous mixing. The objective of this study was to develop a premixed CPC scaffold with macropores suitable for tissue ingrowth. To avoid the on-site powder-liquid mixing, the CPC paste was mixed in advance and did not set in storage; it set only after placement in a physiological solution. Using 30% and 40% mass fractions of mannitol porogen, the premixed CPC scaffold with fibers had flexural strength (mean ± sd; n = 5) of (3.9 ± 1.4) MPa and (1.8 ± 0.8) MPa, respectively. The scaffold porosity reached (68.6 ± 0.7)% and (74.7 ± 1.2)%, respectively. Osteoblast cells colonized in the surface macropores of the scaffold and attached to the hydroxyapatite crystals. Cell viability values for the premixed CPC scaffold was not significantly different from that of a conventional non-premixed CPC known to be biocompatible (P > 0.1). In conclusion, using fast-dissolving porogen and slow-dissolving fibers, a premixed macroporous CPC scaffold was developed with strength approaching the reported strengths of sintered porous hydroxyapatite implants and cancellous bone, and non-cytotoxicity similar to a biocompatible non-premixed CPC. PMID:17277972

  2. Porous polymer media

    DOEpatents

    Shepodd, Timothy J. (Livermore, CA)

    2002-01-01

    Highly crosslinked monolithic porous polymer materials for chromatographic applications. By using solvent compositions that provide not only for polymerization of acrylate monomers in such a fashion that a porous polymer network is formed prior to phase separation but also for exchanging the polymerization solvent for a running buffer using electroosmotic flow, the need for high pressure purging is eliminated. The polymer materials have been shown to be an effective capillary electrochromatographic separations medium at lower field strengths than conventional polymer media. Further, because of their highly crosslinked nature these polymer materials are structurally stable in a wide range of organic and aqueous solvents and over a pH range of 2-12.

  3. Design, construction and mechanical testing of digital 3D anatomical data-based PCL-HA bone tissue engineering scaffold.

    PubMed

    Yao, Qingqiang; Wei, Bo; Guo, Yang; Jin, Chengzhe; Du, Xiaotao; Yan, Chao; Yan, Junwei; Hu, Wenhao; Xu, Yan; Zhou, Zhi; Wang, Yijin; Wang, Liming

    2015-01-01

    The study aims to investigate the techniques of design and construction of CT 3D reconstructional data-based polycaprolactone (PCL)-hydroxyapatite (HA) scaffold. Femoral and lumbar spinal specimens of eight male New Zealand white rabbits were performed CT and laser scanning data-based 3D printing scaffold processing using PCL-HA powder. Each group was performed eight scaffolds. The CAD-based 3D printed porous cylindrical stents were 16 piece × 3 groups, including the orthogonal scaffold, the Pozi-hole scaffold and the triangular hole scaffold. The gross forms, fiber scaffold diameters and porosities of the scaffolds were measured, and the mechanical testing was performed towards eight pieces of the three kinds of cylindrical scaffolds, respectively. The loading force, deformation, maximum-affordable pressure and deformation value were recorded. The pore-connection rate of each scaffold was 100 % within each group, there was no significant difference in the gross parameters and micro-structural parameters of each scaffold when compared with the design values (P > 0.05). There was no significant difference in the loading force, deformation and deformation value under the maximum-affordable pressure of the three different cylinder scaffolds when the load was above 320 N. The combination of CT and CAD reverse technology could accomplish the design and manufacturing of complex bone tissue engineering scaffolds, with no significant difference in the impacts of the microstructures towards the physical properties of different porous scaffolds under large load. PMID:25596860

  4. Characterization of chitosan-gelatin scaffolds for dermal tissue engineering.

    PubMed

    Tseng, Hsiang-Jung; Tsou, Tai-Li; Wang, Hsian-Jenn; Hsu, Shan-Hui

    2013-01-01

    Porous scaffolds for dermal tissue engineering were fabricated by freeze-drying a mixture of chitosan and gelatin (CG) solutions. Different crosslinking agents including glutaraldehyde, 1-(3-dimethylaminopropyl)-3-ethyl-carbodimide hydrochloride (EDC), and genipin were used to crosslink the scaffolds and improve their biostability. The porous structure and mechanical properties were determined for the scaffolds. The proliferation of human fibroblasts in the scaffolds was analyzed. It was found that EDC crosslinked scaffolds had the greatest amount of cells after four days. EDC crosslinked CG scaffolds had tensile modulus in a dry state and compressive modulus in a wet state similar to commercial collagen wound dressing. They also showed appropriate pore size, high water absorption, and good dimensional stability during cell culture. When human fibroblasts were seeded on acellular porcine dermis (APD), acellular human dermis (AHD), and CG scaffolds for 3D cell culture, they were well-distributed in the centre of the CG scaffolds but stayed only on the superficial layer of APD or AHD after seven days. A gelatin-based bioglue was applied to the CG scaffolds where the keratinocytes were seeded to mimic epidermal structure. After 14 days, the bioglue degraded and keratinocytes grew to form monolayers on the scaffolds. This study showed that CG scaffolds crosslinked by EDC and seeded with human fibroblasts could serve as dermal constructs, while the bioglue coating seeded with keratinocytes could serve as an epidermal construct. Such a combination could help regenerate skin with integrated dermal and epidermal layers and a have potential use in tissue-engineered skin. PMID:22034441

  5. Composite scaffolds of mesoporous bioactive glass and polyamide for bone repair.

    PubMed

    Su, Jiacan; Cao, Liehu; Yu, Baoqing; Song, Shaojun; Liu, Xinwei; Wang, Zhiwei; Li, Ming

    2012-01-01

    A bone-implanted porous scaffold of mesoporous bioglass/polyamide composite (m-BPC) was fabricated, and its biological properties were investigated. The results indicate that the m-BPC scaffold contained open and interconnected macropores ranging 400-500 ?m, and exhibited a porosity of 76%. The attachment ratio of MG-63 cells on m-BPC was higher than polyamide scaffolds at 4 hours, and the cells with normal phenotype extended well when cultured with m-BPC and polyamide scaffolds. When the m-BPC scaffolds were implanted into bone defects of rabbit thighbone, histological evaluation confirmed that the m-BPC scaffolds exhibited excellent biocompatibility and osteoconductivity, and more effective osteogenesis than the polyamide scaffolds in vivo. The results indicate that the m-BPC scaffolds improved the efficiency of new bone regeneration and, thus, have clinical potential for bone repair. PMID:22679367

  6. Bioinspired porous membranes containing polymer nanoparticles for wound healing.

    PubMed

    Ferreira, Ana M; Mattu, Clara; Ranzato, Elia; Ciardelli, Gianluca

    2014-12-01

    Skin damages covering a surface larger than 4 cm(2) require a regenerative strategy based on the use of appropriate wound dressing supports to facilitate the rapid tissue replacement and efficient self-healing of the lost or damaged tissue. In the present work, A novel biomimetic approach is proposed for the design of a therapeutic porous construct made of poly(L-lactic acid) (PLLA) fabricated by thermally induced phase separation (TIPS). Biomimicry of ECM was achieved by immobilization of type I collagen through a two-step plasma treatment for wound healing. Anti-inflammatory (indomethacin)-containing polymeric nanoparticles (nps) were loaded within the porous membranes in order to minimize undesired cell response caused by post-operative inflammation. The biological response to the scaffold was analyzed by using human keratinocytes cell cultures. In this work, a promising biomimetic construct for wound healing and soft tissue regeneration with drug-release properties was fabricated since it shows (i) proper porosity, pore size, and mechanical properties, (ii) biomimicry of ECM, and (iii) therapeutic potential. PMID:24522948

  7. Three-Dimensional Scaffolds Offer New Tool to Study Cancer | Physical Sciences in Oncology

    Cancer.gov

    Porous polymer scaffolds fabricated to support the growth of biological tissue for implantation may hold the potential to greatly accelerate the development of cancer therapeutics, according to research published in the Proceedings of the National Academy of Sciences.

  8. Neural stem cell differentiation in collagen scaffolds for retinal tissue engineering

    E-print Network

    Ueda, Erica (Erica Ann)

    2008-01-01

    Rat neural stem cells (NSCs) were cultured in monolayer or in porous collagen scaffolds and exposed to neurogenic or non-neurogenic medium to determine the effects on neural differentiation and neurite growth. Nestin, ...

  9. Microfluidic devices and methods including porous polymer monoliths

    DOEpatents

    Hatch, Anson V.; Sommer, Gregory j.; Singh, Anup K.; Wang, Ying-Chih; Abhyankar, Vinay

    2015-12-01

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  10. Microfluidic devices and methods including porous polymer monoliths

    DOEpatents

    Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

    2014-04-22

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  11. Electrically conductive chitosan/carbon scaffolds for cardiac tissue engineering.

    PubMed

    Martins, Ana M; Eng, George; Caridade, Sofia G; Mano, João F; Reis, Rui L; Vunjak-Novakovic, Gordana

    2014-02-10

    In this work, carbon nanofibers were used as doping material to develop a highly conductive chitosan-based composite. Scaffolds based on chitosan only and chitosan/carbon composites were prepared by precipitation. Carbon nanofibers were homogeneously dispersed throughout the chitosan matrix, and the composite scaffold was highly porous with fully interconnected pores. Chitosan/carbon scaffolds had an elastic modulus of 28.1 ± 3.3 KPa, similar to that measured for rat myocardium, and excellent electrical properties, with a conductivity of 0.25 ± 0.09 S/m. The scaffolds were seeded with neonatal rat heart cells and cultured for up to 14 days, without electrical stimulation. After 14 days of culture, the scaffold pores throughout the construct volume were filled with cells. The metabolic activity of cells in chitosan/carbon constructs was significantly higher as compared to cells in chitosan scaffolds. The incorporation of carbon nanofibers also led to increased expression of cardiac-specific genes involved in muscle contraction and electrical coupling. This study demonstrates that the incorporation of carbon nanofibers into porous chitosan scaffolds improved the properties of cardiac tissue constructs, presumably through enhanced transmission of electrical signals between the cells. PMID:24417502

  12. Parameters optimization for the fabrication of phosphate glass/hydroxyapatite nanocomposite scaffold

    NASA Astrophysics Data System (ADS)

    Govindan, R.; Girija, E. K.

    2015-06-01

    Three-dimensional, highly porous, bioactive and biodegradable phosphate glass and nanohydroxyapatite (n-HA) composite scaffolds was fabricated by the polymer foam replication technique. Polyurethane foam (PU) and polyvinyl alcohol (PVA) were used as template and binder, respectively. Optimization of composition and sintering temperature is carried out for tissue engineering scaffold fabrication.

  13. Characterization and cytocompatibility of biphasic calcium phosphate/polyamide 6 scaffolds for bone regeneration.

    PubMed

    Shen, Juan; Li, Yubao; Zuo, Yi; Zou, Qin; Cheng, Lin; Zhang, Li; Gong, Mei; Gao, Shibo

    2010-11-01

    Porous scaffolds of biphasic calcium phosphate (BCP)/polyamide 6 (PA6) with weight ratios of 30/70, 45/55, and 55/45 have been fabricated through a modified thermally induced phase separation technique. The chemical structure properties, macrostructure, and mechanical strength of the scaffolds were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and mechanical testing. The results indicated that the BCP/PA6 scaffolds had an interconnected porous structure with a pore size mainly ranging from 100 to 900 ?m and many micropores on the rough pore walls. The mechanical property of the scaffold was significantly enhanced by the addition of BCP inorganic fillers. The 55/45 BCP/PA6 composite scaffold with 76.5% ± 2.1% porosity attained a compressive strength of 1.86 ± 0.14 MPa. Moreover, the BCP/PA6 porous scaffold was cultured with rat calvarial osteoblasts to investigate the cell proliferation, viability, and differentiation function (alkaline phosphatase). The type I collagen expression was also used to characterize the differentiation of rat calvarial osteoblasts on BCP/PA6 composite scaffold by immunocytochemistry. The in vitro cytocompatibility evaluation demonstrated that the BCP/PA6 scaffold acted as a good template for the cells adhesion, spreading, growth, and differentiation. These results suggest that the BCP/PA6 porous composite could be a candidate as an excellent substitute for damaged or defect bone. PMID:20878919

  14. Active scaffolds for on-demand drug and cell delivery Xuanhe Zhaoa,b

    E-print Network

    Suresh, Subra

    Materials Laboratory, Department of Mechanical Engineering and Materials Science, Duke University, Durham as scaffolds in tissue engineering and cell-based therapies. The release of biological agents from conventional for controlled de- livery (19­24). On the other hand, the porous scaffolds currently used in tissue engineering

  15. Three-dimensional polycaprolactone scaffold via needleless electrospinning promotes cell proliferation and infiltration.

    PubMed

    Li, Dawei; Wu, Tong; He, Nanfei; Wang, Jing; Chen, Weiming; He, Liping; Huang, Chen; Ei-Hamshary, Hany A; Al-Deyab, Salem S; Ke, Qinfei; Mo, Xiumei

    2014-09-01

    Electrospinning has been widely used in fabrication of tissue engineering scaffolds. Currently, most of the electrospun nanofibers performed like a conventional two-dimensional (2D) membrane, which hindered their further applications. Moreover, the low production rate of the traditional needle-electrospinning (NE) also limited the commercialization. In this article, disc-electrospinning (DE) was utilized to fabricate a three-dimensional (3D) scaffold consisting of porous macro/nanoscale fibers. The morphology of the porous structure was investigated by scanning electron microscopy images, which showed irregular pores of nanoscale spreading on the surface of DE polycaprolactone (PCL) fibers. Protein adsorption assessment illustrated the porous structure could significantly enhance proteins pickup, which was 55% higher than that of solid fiber scaffolds. Fibroblasts were cultured on the scaffold. The results demonstrated that DE fiber scaffold could enhance initial cell attachment. In the 7 days of culture, fibroblasts grew faster on DE fiber scaffold in comparison with solid fiber, solvent cast (SC) film and TCP. Fibroblasts on DE fibers showed a stretched shape and integrated with the porous surface tightly. Cells were also found to migrate into the DE scaffold up to 800?m. Results supported the use of DE PCL fibers as a 3D tissue engineering scaffold in soft tissue regeneration. PMID:24996758

  16. EFFECT OF SCAFFOLD MICROARCHITECTURE ON OSTEOGENIC DIFFERENTIATION OF HUMAN MESENCHYMAL STEM CELLS

    PubMed Central

    Kim, Su Hee; Kim, Soo Hyun; Yamaguchi, Tomonori; Masuda, Koichi; Varghese, Shyni

    2015-01-01

    Design of macroporous synthetic grafts that can promote infiltration of cells, their differentiation, and synthesis of bone-specific extracellular matrix is a key determinant for in vivo bone tissue regeneration and repair. In this study, we investigated the effect of the microarchitecture of the scaffold on osteogenic differentiation of human mesenchymal stem cells (hMSCs). Poly(ethylene glycol) diacrylate-co-N-acryloyl 6-aminocaproic acid cryogels were fabricated to have either a pore network consisting of cellular, randomly oriented pores (termed ‘spongy’) or a pore network consisting of lamellar columns (termed ‘columnar’), with both cryogel types showing a similar porosity. Both spongy and columnar cryogels supported comparable levels of cell viability and proliferation of hMSCs in vitro. However, spongy cryogels promoted osteogenic differentiation to a greater extent than their columnar counterparts, as evidenced by increased alkaline phosphatase activity and osteoblastic gene expression over 21 days post culture. Leveraging upon our previous work, we further evaluated the ability of these synthetic scaffolds in conjunction with mineralisation to promote ectopic bone formation upon subcutaneous implantation in nude rats. Mineralised spongy and columnar cryogels, both in the presence and absence of exogenous hMSCs, promoted ectopic bone formation in vivo. No such bone formation was observed in acellular cryogels devoid of mineralisation, with extensive host cell infiltration and vascularisation in columnar cryogels, and negligible infiltration into spongy cryogels. Our results thus present a novel method to tune the microarchitecture of porous polymeric scaffolds, in addition to suggesting their efficacy as synthetic bone grafts. PMID:23329467

  17. Enhanced cell colonization of collagen scaffold by ultraviolet/ozone surface processing.

    PubMed

    Liu, Chaozong; McKenna, Fiona-Mairead; Liang, He; Johnstone, Alan; Abel, Eric W

    2010-12-01

    Both physical and chemical crosslinking methods have been shown to be effective in improving the biological stability and mechanical properties of porous collagen scaffolds. However, the wetting of the collagen fibril surface by a culture medium is reduced and it is difficult for the medium to diffuse into the 3D structure of a porous collagen scaffold. This article reports a strategy for the surface processing of crosslinked collagen scaffolds by an integrated ultraviolet/ozone perfuse processing technique. Ultraviolet/ozone perfuse processing improved surface wettability for both the exterior and interior surfaces of the porous 3D collagen scaffold. This leads to a significant improvement in the scaffolds ability to take up water without compromising the bulk biological stability and mechanical properties. In vitro evaluation using mesenchymal stem cell demonstrated that surface processing enhanced cell colonization of the scaffolds, cells could migrate deep into the structure of the scaffolds, and significantly higher levels of cell proliferation were achieved. In contrast, the cells were unable to migrate deep into the scaffolds, and most of the cells that survived were observed only in the top seeding layer resulting in a low level of cell activity in the unprocessed scaffolds. PMID:20218815

  18. In-situ polymerization PLOT columns I: divinylbenzene

    NASA Technical Reports Server (NTRS)

    Shen, T. C.

    1992-01-01

    A novel method for preparation of porous-layer open-tubular (PLOT) columns is described. The method involves a simple and reproducible, straight-forward in-situ polymerization of monomer directly on the metal tube.

  19. Effects of designed PLLA and 50:50PLGA scaffold architectures on bone formation in vivo

    PubMed Central

    Saito, Eiji; Liao, Elly E.; Hu, Wei-Wen; Krebsbach, Paul H.; Hollister, Scott J.

    2015-01-01

    Biodegradable porous scaffolds have been investigated as an alternative approach to current metal, ceramic, and polymer bone graft substitutes for lost or damaged bone tissues. Although there have been many studies investigating the effects of scaffold architecture on bone formation, many of these scaffolds were fabricated using conventional methods, such as salt leaching and phase separation, and were constructed without designed architecture. To study the effects of both designed architecture and material on bone formation, we designed and fabricated three types of porous scaffold architecture from two biodegradable materials, poly (L-lactic acid) (PLLA) and 50:50Poly (lactic-co-glycolic acid) (PLGA) using image based design and indirect solid freeform fabrication techniques, seeded them with bone morphogenic protein-7 transduced human gingival fibroblasts and implanted them subcutaneously into mice for 4 and 8 weeks. Micro-computed tomography data confirmed that the fabricated porous scaffolds replicated the designed architectures. Histological analysis revealed that the 50:50PLGA scaffolds degraded and did not maintain their architecture after 4 weeks. The PLLA scaffolds maintained their architecture at both time points and showed improved bone ingrowth which followed the internal architecture of the scaffolds. Mechanical properties of both PLLA and 50:50PLGA scaffolds decreased, but PLLA scaffolds maintained greater mechanical properties than 50:50PLGA after implantation. The increase of mineralized tissue helped to support mechanical properties of bone tissue and scaffold constructs from 4 to 8 weeks. The results indicated the importance of choice of scaffold materials and computationally designed scaffolds to control tissue formation and mechanical properties for desired bone tissue regeneration. PMID:22162220

  20. Polymeric nitrogen

    SciTech Connect

    Mailhiot, C.; Yang, L.H.; McMahan, A.K. )

    1992-12-01

    The equilibrium phase boundary between single-bonded, threefold-coordinated polymeric forms of nitrogen, and the observed, triple-bonded diatomic phases, is predicted to occur at relatively low (50[plus minus]15 GPa) pressure. This conclusion is based on extensive local-density-functional total-energy calculations for polymeric structures (including that of black phosphorus, and another with all [ital gauche] dihedral angles) and diatomic structures (including that of the observed high-pressure [var epsilon]-N[sub 2] phase). We believe the diatomic phase of nitrogen, observed up to 180 GPa and room temperature, to be metastable at these conditions, and that such hysteresis enhances the prospects for the existence of a metastable polymeric form of nitrogen at ambient conditions. In this regard, we show that the black-phosphorus and cubic [ital gauche] polymeric forms of nitrogen would encounter significant barriers along high-symmetry paths to dimerization at atmospheric pressure.

  1. Porous polymer catalysts with hierarchical structures.

    PubMed

    Sun, Qi; Dai, Zhifeng; Meng, Xiangju; Xiao, Feng-Shou

    2015-10-01

    The emergence of porous organic polymers (POPs) has provided great opportunities for new applications in heterogeneous catalysis owing to their unprecedented intrinsic structural features such as high surface areas, extraordinary framework stabilities and chemically adjustable compositions. In this tutorial review, representative recent developments in the POPs-based catalysts with hierarchically porous structures are presented. Various strategies for the syntheses of hierarchically porous polymers including hard-templating, soft-templating and template-free approaches and the design of catalytically active porous polymers including post-modification, co-polymerization and self-polymerization have been discussed. In addition, their catalytic properties are compared. Finally, we emphasize the importance of the synthesis of hierarchically porous polymer based heterogeneous catalysts using sustainable routes under template-free and metal-free conditions. PMID:26505055

  2. Biologically inspired growth of hydroxyapatite crystals on bio-organics-defined scaffolds

    SciTech Connect

    Yang, Chunrong; Li, Yuli; Nan, Kaihui

    2013-03-15

    Graphical abstract: Petal-like crystals were observed to form on the surface of the BG/COL/ChS scaffolds. Highlights: ? Porous scaffolds were prepared using bioglass, collagen and chondroitin sulfate. ? Highly oriented HA crystals were grown on scaffolds using simulated body fluids ? The microstructure and orientation of HA were explained by molecular configuration. - Abstract: Several bio-organics-defined composite scaffolds were prepared using 58s-bioglass (BG), collagen (Col) and chondroitin sulfate (ChS). These scaffolds possess highly porous structure. X-ray diffraction of these scaffolds strongly indicated that hydroxyapatite (HA) crystals formed on their surfaces in simulated body fluids within 3 d, and similar formation process of crystals could be obtained on BG/Col and BG/Col/ChS scaffolds. The morphology and structure of the crystals were further examined by scanning electron microscopy. The results obtained indicate that an apatite with petal-like structure similar to that found on BG/Col scaffolds can be produced on BG/Col/ChS scaffolds through biomimetic synthesis, while that on BG/ChS scaffolds took place differently. The differences could be explained by self-assembly processes and the different macromolecular configurations of the Col and ChS fibrils which self-assemble spontaneously into their fibers. On the other hand, the bio-organics-defined composites have good cell biocompability. The results may be applicable to develop tailored biomaterials for peculiar bone substitute.

  3. Hydrophilic PCU scaffolds prepared by grafting PEGMA and immobilizing gelatin to enhance cell adhesion and proliferation.

    PubMed

    Shi, Changcan; Yuan, Wenjie; Khan, Musammir; Li, Qian; Feng, Yakai; Yao, Fanglian; Zhang, Wencheng

    2015-05-01

    Gelatin contains many functional motifs which can modulate cell specific adhesion, so we modified polycarbonate urethane (PCU) scaffold surface by immobilization of gelatin. PCU-g-gelatin scaffolds were prepared by direct immobilizing gelatins onto the surface of aminated PCU scaffolds. To increase the immobilization amount of gelatin, poly(ethylene glycol) methacrylate (PEGMA) was grafted onto PCU scaffolds by surface initiated atom transfer radical polymerization. Then, following amination and immobilization, PCU-g-PEGMA-g-gelatin scaffolds were obtained. Both modified scaffolds were characterized by chemical and biological methods. After immobilization of gelatin, the microfiber surface became rough, but the original morphology of scaffolds was maintained successfully. PCU-g-PEGMA-g-gelatin scaffolds were more hydrophilic than PCU-g-gelatin scaffolds. Because hydrophilic PEGMA and gelatin were grafted and immobilized onto the surface, the PCU-g-PEGMA-g-gelatin scaffolds showed low platelet adhesion, perfect anti-hemolytic activity and excellent cell growth and proliferation capacity. It could be envisioned that PCU-g-PEGMA-g-gelatin scaffolds might have potential applications in tissue engineering artificial scaffolds. PMID:25746263

  4. Biomimetic magnetic silk scaffolds.

    PubMed

    Samal, Sangram K; Dash, Mamoni; Shelyakova, Tatiana; Declercq, Heidi A; Uhlarz, Marc; Bañobre-López, Manuel; Dubruel, Peter; Cornelissen, Maria; Herrmannsdörfer, Thomas; Rivas, Jose; Padeletti, Giuseppina; De Smedt, Stefaan; Braeckmans, Kevin; Kaplan, David L; Dediu, V Alek

    2015-03-25

    Magnetic silk fibroin protein (SFP) scaffolds integrating magnetic materials and featuring magnetic gradients were prepared for potential utility in magnetic-field assisted tissue engineering. Magnetic nanoparticles (MNPs) were introduced into SFP scaffolds via dip-coating methods, resulting in magnetic SFP scaffolds with different strengths of magnetization. Magnetic SFP scaffolds showed excellent hyperthermia properties achieving temperature increases up to 8 °C in about 100 s. The scaffolds were not toxic to osteogenic cells and improved cell adhesion and proliferation. These findings suggest that tailored magnetized silk-based biomaterials can be engineered with interesting features for biomaterials and tissue-engineering applications. PMID:25734962

  5. Understanding anisotropy and architecture in ice-templated biopolymer scaffolds.

    PubMed

    Pawelec, K M; Husmann, A; Best, S M; Cameron, R E

    2014-04-01

    Biopolymer scaffolds have great therapeutic potential within tissue engineering due to their large interconnected porosity and biocompatibility. Using an ice-templated technique, where collagen is concentrated into a porous network by ice nucleation and growth, scaffolds with anisotropic pore architecture can be created, mimicking natural tissues like cardiac muscle and bone. This paper describes a systematic set of experiments undertaken to understand the effect of local temperatures on architecture in ice-templated biopolymer scaffolds. The scaffolds within this study were at least 10mm in all dimensions, making them applicable to critical sized defects for biomedical applications. It was found that monitoring the local freezing behavior within the slurry was critical to predicting scaffold structure. Aligned porosity was produced only in parts of the slurry volume which were above the equilibrium freezing temperature (0°C) at the time when nucleation first occurs in the sample as a whole. Thus, to create anisotropic scaffolds, local slurry cooling rates must be sufficiently different to ensure that the equilibrium freezing temperature is not reached throughout the slurry at nucleation. This principal was valid over a range of collagen slurries, demonstrating that by monitoring the temperature within slurry during freezing, scaffold anisotropy with ice-templated scaffolds can be predicted. PMID:24582233

  6. Mesoporous bioactive glass nanolayer-functionalized 3D-printed scaffolds for accelerating osteogenesis and angiogenesis.

    PubMed

    Zhang, Yali; Xia, Lunguo; Zhai, Dong; Shi, Mengchao; Luo, Yongxiang; Feng, Chun; Fang, Bing; Yin, Jingbo; Chang, Jiang; Wu, Chengtie

    2015-12-01

    The hierarchical microstructure, surface and interface of biomaterials are important factors influencing their bioactivity. Porous bioceramic scaffolds have been widely used for bone tissue engineering by optimizing their chemical composition and large-pore structure. However, the surface and interface of struts in bioceramic scaffolds are often ignored. The aim of this study is to incorporate hierarchical pores and bioactive components into the bioceramic scaffolds by constructing nanopores and bioactive elements on the struts of scaffolds and further improve their bone-forming activity. Mesoporous bioactive glass (MBG) modified ?-tricalcium phosphate (MBG-?-TCP) scaffolds with a hierarchical pore structure and a functional strut surface (?100 nm of MBG nanolayer) were successfully prepared via 3D printing and spin coating. The compressive strength and apatite-mineralization ability of MBG-?-TCP scaffolds were significantly enhanced as compared to ?-TCP scaffolds without the MBG nanolayer. The attachment, viability, alkaline phosphatase (ALP) activity, osteogenic gene expression (Runx2, BMP2, OPN and Col I) and protein expression (OPN, Col I, VEGF, HIF-1?) of rabbit bone marrow stromal cells (rBMSCs) as well as the attachment, viability and angiogenic gene expression (VEGF and HIF-1?) of human umbilical vein endothelial cells (HUVECs) in MBG-?-TCP scaffolds were significantly upregulated compared with conventional bioactive glass (BG)-modified ?-TCP (BG-?-TCP) and pure ?-TCP scaffolds. Furthermore, MBG-?-TCP scaffolds significantly enhanced the formation of new bone in vivo as compared to BG-?-TCP and ?-TCP scaffolds. The results suggest that application of the MBG nanolayer to modify 3D-printed bioceramic scaffolds offers a new strategy to construct hierarchically porous scaffolds with significantly improved physicochemical and biological properties, such as mechanical properties, osteogenesis, angiogenesis and protein expression for bone tissue engineering applications, in which the incorporation of nanostructures and bioactive components into the scaffold struts synergistically play a key role in the improved bone formation. PMID:26525451

  7. Mesoporous bioactive glass nanolayer-functionalized 3D-printed scaffolds for accelerating osteogenesis and angiogenesis

    NASA Astrophysics Data System (ADS)

    Zhang, Yali; Xia, Lunguo; Zhai, Dong; Shi, Mengchao; Luo, Yongxiang; Feng, Chun; Fang, Bing; Yin, Jingbo; Chang, Jiang; Wu, Chengtie

    2015-11-01

    The hierarchical microstructure, surface and interface of biomaterials are important factors influencing their bioactivity. Porous bioceramic scaffolds have been widely used for bone tissue engineering by optimizing their chemical composition and large-pore structure. However, the surface and interface of struts in bioceramic scaffolds are often ignored. The aim of this study is to incorporate hierarchical pores and bioactive components into the bioceramic scaffolds by constructing nanopores and bioactive elements on the struts of scaffolds and further improve their bone-forming activity. Mesoporous bioactive glass (MBG) modified ?-tricalcium phosphate (MBG-?-TCP) scaffolds with a hierarchical pore structure and a functional strut surface (~100 nm of MBG nanolayer) were successfully prepared via 3D printing and spin coating. The compressive strength and apatite-mineralization ability of MBG-?-TCP scaffolds were significantly enhanced as compared to ?-TCP scaffolds without the MBG nanolayer. The attachment, viability, alkaline phosphatase (ALP) activity, osteogenic gene expression (Runx2, BMP2, OPN and Col I) and protein expression (OPN, Col I, VEGF, HIF-1?) of rabbit bone marrow stromal cells (rBMSCs) as well as the attachment, viability and angiogenic gene expression (VEGF and HIF-1?) of human umbilical vein endothelial cells (HUVECs) in MBG-?-TCP scaffolds were significantly upregulated compared with conventional bioactive glass (BG)-modified ?-TCP (BG-?-TCP) and pure ?-TCP scaffolds. Furthermore, MBG-?-TCP scaffolds significantly enhanced the formation of new bone in vivo as compared to BG-?-TCP and ?-TCP scaffolds. The results suggest that application of the MBG nanolayer to modify 3D-printed bioceramic scaffolds offers a new strategy to construct hierarchically porous scaffolds with significantly improved physicochemical and biological properties, such as mechanical properties, osteogenesis, angiogenesis and protein expression for bone tissue engineering applications, in which the incorporation of nanostructures and bioactive components into the scaffold struts synergistically play a key role in the improved bone formation.

  8. In vivo Degradation of Three-Dimensional Silk Fibroin Scaffolds

    PubMed Central

    Wang, Yongzhong; Rudym, Darya D.; Walsh, Ashley; Abrahamsen, Lauren; Kim, Hyeon-Joo; Kim, Hyun Suk; Kirker-Head, Carl; Kaplan, David L.

    2011-01-01

    Three-dimensional porous scaffolds prepared from regenerated silk fibroin using either an all aqueous process or a process involving an organic solvent, hexafluoroisopropanol (HFIP) have shown promise in cell culture and tissue engineering applications. However, their biocompatibility and in vivo degradation has not been fully established. The present study was conducted to systematically investigate how processing method (aqueous vs. organic solvent) and processing variables (silk fibroin concentration and pore size) affect the short-term (up to 2 months) and long-term (up to 1 year) in vivo behavior of the protein scaffolds in both nude and Lewis rats. The samples were analyzed by histology for scaffold morphological changes and tissue ingrowth, and by real-time RT-PCR and immunohistochemistry for immune responses. Throughout the period of implantation, all scaffolds were well-tolerated by the host animals and immune responses to the implants were mild. Most scaffolds prepared from the all aqueous process degraded to completion between two and six months, while those prepared from organic solvent (hexafluoroisopropanol (HFIP)) process persisted beyond one year. Due to widespread cellular invasion throughout the scaffold, the degradation of aqueous-derived scaffolds appears to be more homogeneous than that of HFIP-derived scaffolds. In general and especially for the HFIP-derived scaffolds, a higher original silk fibroin concentration (e.g. 17%) and smaller pore size (e.g. 100–200 µm) resulted in lower levels of tissue ingrowth and slower degradation. These results demonstrate that the in vivo behavior of the three-dimensional silk fibroin scaffolds is related to the morphological and structural features that resulted from different scaffold preparation processes. The insights gained in this study can serve as a guide for processing scenarios to match desired morphological and structural features and degradation time with tissue-specific applications. PMID:18502501

  9. Three-dimensional, bioactive, biodegradable, polymerbioactive glass composite scaffolds with

    E-print Network

    Lu, Helen H.

    Three-dimensional, bioactive, biodegradable, polymer­bioactive glass composite scaffolds alternative to biologi- cal and synthetic grafts. The biomaterial component is a critical determinant (3-D), porous composite of polylactide-co-glycolide (PLAGA) and 45S5 bioactive glass (BG

  10. Three-Dimensional Metal Scaffold Supported Bicontinuous Silicon Battery Anodes

    E-print Network

    Braun, Paul

    templated porous nickel metal scaffold, which maintains electrical connectivity during cycling due the silicon volume change and electrically conductive.12 Results obtained by dispersing silicon nanoparticles that of pure silicon.3,13 Rather than dispersing silicon nanoparticles in a second phase, several reports have

  11. Enhancement of neurite outgrowth in neuron cancer stem cells by growth on 3-D collagen scaffolds

    SciTech Connect

    Chen, Chih-Hao; Neurosurgery, Department of Surgery, Kaohsiung Veterans General Hospital, Taiwan, ROC; Department of Biomedical Engineering, I-Shou University, Taiwan, ROC ; Kuo, Shyh Ming; Liu, Guei-Sheung; Chen, Wan-Nan U.; Chuang, Chin-Wen; Liu, Li-Feng

    2012-11-09

    Highlights: Black-Right-Pointing-Pointer Neuron cancer stem cells (NCSCs) behave high multiply of growth on collagen scaffold. Black-Right-Pointing-Pointer Enhancement of NCSCs neurite outgrowth on porous collagen scaffold. Black-Right-Pointing-Pointer 3-D collagen culture of NCSCs shows an advance differentiation than 2-D culture. -- Abstract: Collagen is one component of the extracellular matrix that has been widely used for constructive remodeling to facilitate cell growth and differentiation. The 3-D distribution and growth of cells within the porous scaffold suggest a clinical significance for nerve tissue engineering. In the current study, we investigated proliferation and differentiation of neuron cancer stem cells (NCSCs) on a 3-D porous collagen scaffold that mimics the natural extracellular matrix. We first generated green fluorescence protein (GFP) expressing NCSCs using a lentiviral system to instantly monitor the transitions of morphological changes during growth on the 3-D scaffold. We found that proliferation of GFP-NCSCs increased, and a single cell mass rapidly grew with unrestricted expansion between days 3 and 9 in culture. Moreover, immunostaining with neuronal nuclei (NeuN) revealed that NCSCs grown on the 3-D collagen scaffold significantly enhanced neurite outgrowth. Our findings confirmed that the 80 {mu}m porous collagen scaffold could enhance attachment, viability and differentiation of the cancer neural stem cells. This result could provide a new application for nerve tissue engineering and nerve regeneration.

  12. Bio-mimetic hollow scaffolds for long bone replacement

    NASA Astrophysics Data System (ADS)

    Müller, Bert; Deyhle, Hans; Fierz, Fabienne C.; Irsen, Stephan H.; Yoon, Jin Y.; Mushkolaj, Shpend; Boss, Oliver; Vorndran, Elke; Gburek, Uwe; Degistirici, Özer; Thie, Michael; Leukers, Barbara; Beckmann, Felix; Witte, Frank

    2009-08-01

    The tissue engineering focuses on synthesis or regeneration of tissues and organs. The hierarchical structure of nearly all porous scaffolds on the macro, micro- and nanometer scales resembles that of engineering foams dedicated for technical applications, but differ from the complex architecture of long bone. A major obstacle of scaffold architecture in tissue regeneration is the limited cell infiltration as the result of the engineering approaches. The biological cells seeded on the three-dimensional constructs are finally only located on the scaffold's periphery. This paper reports on the successful realization of calcium phosphate scaffolds with an anatomical architecture similar to long bones. Two base materials, namely nano-porous spray-dried hydroxyapatite hollow spheres and tri-calcium phosphate powder, were used to manufacture cylindrically shaped, 3D-printed scaffolds with micro-passages and one central macro-canal following the general architecture of long bones. The macro-canal is built for the surgical placement of nerves or larger blood vessels. The micro-passages allow for cell migration and capillary formation through the entire scaffold. Finally, the nanoporosity is essential for the molecule transport crucial for signaling, any cell nutrition and waste removal.

  13. Fabrication and characterization of layered chitosan/silk fibroin/nano-hydroxyapatite scaffolds with designed composition and mechanical properties.

    PubMed

    Zhou, Ting; Wu, Jingjing; Liu, Jiaoyan; Luo, Ying; Wan, Ying

    2015-08-01

    Chitosan/nano-hydroxyapatite (HA) composites were first prepared and then used together with chitosan and silk fibroin (SF) to produce a type of four-layer porous scaffold that is potentially applicable for articular cartilage repair. The bottom layer of the scaffold was built with the chitosan/HA composite and the other three layers of the scaffold were fabricated using chitosan/SF composites in which the content of the chitosan and SF was altered in a mutually reversed trend. The so-produced chitosan/SF/HA scaffolds were further crosslinked using tripolyphosphate to achieve enhanced mechanical properties. Interconnected porous microstructures throughout the scaffolds were constructed using a temperature gradient processing technique, and the resultant scaffolds were endowed with graded pore-sizes and porosities as well as porous interface zones between contiguous layers without visual clefts. The compressive modulus and stress at 10% strain of the scaffolds in wet state showed a gradient-changed trend which partially mimics the compressive mechanical properties of an articular cartilage matrix. Cell culture on some chitosan/SF/HA scaffolds for a period of time of up to 14?d showed that the scaffolds were able to well support the growth and infiltration of cells, suggesting that the presently developed chitosan/SF/HA scaffolds have promising potential for articular cartilage repair. PMID:26225911

  14. Fabrication of poly (?-caprolactone) microfiber scaffolds with varying topography and mechanical properties for stem cell-based tissue engineering applications.

    PubMed

    Ko, Junghyuk; Mohtaram, Nima Khadem; Ahmed, Farid; Montgomery, Amy; Carlson, Michael; Lee, Patrick C D; Willerth, Stephanie M; Jun, Martin B G

    2014-01-01

    Highly porous poly (?-caprolactone) microfiber scaffolds can be fabricated using electrospinning for tissue engineering applications. Melt electrospinning produces such scaffolds by direct deposition of a polymer melt instead of dissolving the polymer in a solvent as performed during solution electrospinning. The objective of this study was to investigate the significant parameters associated with the melt electrospinning process that influence fiber diameter and scaffold morphology, including processing temperature, collection distance, applied, voltage and nozzle size. The mechanical properties of these microfiber scaffolds varied with microfiber diameter. Additionally, the porosity of scaffolds was determined by combining experimental data with mathematical modeling. To test the cytocompatability of these fibrous scaffolds, we seeded neural progenitors derived from murine R1 embryonic stem cell lines onto these scaffolds, where they could survive, migrate, and differentiate into neurons; demonstrating the potential of these melt electrospun scaffolds for tissue engineering applications. PMID:23998440

  15. Conductive Polymeric Binder for Lithium-Ion Battery Anode

    NASA Astrophysics Data System (ADS)

    Gao, Tianxiang

    Tin (Sn) has a high-specific capacity (993 mAhg-1) as an anode material for Li-ion batteries. To overcome the poor cycling performance issue caused by its large volume expansion and pulverization during the charging and discharging process, many researchers put efforts into it. Most of the strategies are through nanostructured material design and introducing conductive polymer binders that serve as matrix of the active material in anode. This thesis aims for developing a novel method for preparing the anode to improve the capacity retention rate. This would require the anode to have high electrical conductivity, high ionic conductivity, and good mechanical properties, especially elasticity. Here the incorporation of a conducting polymer and a conductive hydrogel in Sn-based anodes using a one-step electrochemical deposition via a 3-electrode cell method is reported: the Sn particles and conductive component can be electrochemically synthesized and simultaneously deposited into a hybrid thin film onto the working electrode directly forming the anode. A well-defined three dimensional network structure consisting of Sn nanoparticles coated by conducting polymers is achieved. Such a conductive polymer-hydrogel network has multiple advantageous features: meshporous polymeric structure can offer the pathway for lithium ion transfer between the anode and electrolyte; the continuous electrically conductive polypyrrole network, with the electrostatic interaction with elastic, porous hydrogel, poly (2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylonitrile) (PAMPS) as both the crosslinker and doping anion for polypyrrole (PPy) can decrease the volume expansion by creating porous scaffold and softening the system itself. Furthermore, by increasing the amount of PAMPS and creating an interval can improve the cycling performance, resulting in improved capacity retention about 80% after 20 cycles, compared with only 54% of that of the control sample without PAMPS. The cycle is performed under current of 0.1 C.

  16. Scaffold characterization using NLO multimodal microscopy in metrology for regenerative medicine

    NASA Astrophysics Data System (ADS)

    Mortati, Leonardo; Divieto, Carla; Boffitto, Monica; Sartori, Susanna; Ciardelli, Gianluca; Sassi, Maria Paola

    2013-09-01

    Metrology in regenerative medicine aims to develop traceable measurement technologies for characterizing cellular and macromolecule behaviour in regenerative medicine products and processes. One key component in regenerative medicine is using three-dimensional porous scaffolds to guide cells during the regeneration process. The regeneration of specific tissues guided by tissue analogous substrates is dependent on diverse scaffold architectural properties that can be derived quantitatively from scaffolds images. This paper discuss the results obtained with the multimodal NLO microscope recently realized in our laboratory in characterizing 3D tissue engineered (TE) scaffolds colonized from human Mesenchimal stem cells (hMSC), focusing on the study of the three-dimensional metrological parameters.

  17. Encapsulated boron as an osteoinductive agent for bone scaffolds.

    PubMed

    Gümü?derelio?lu, Menem?e; Tunçay, Ekin Ö; Kaynak, Gökçe; Demirta?, Tolga T; Ayd?n, Seda T??l?; Hakk?, Sema S

    2015-07-01

    The aim of this study was to develop boron (B)-releasing polymeric scaffold to promote regeneration of bone tissue. Boric acid-doped chitosan nanoparticles with a diameter of approx. 175 nm were produced by tripolyphosphate (TPP)-initiated ionic gelation process. The nanoparticles strongly attached via electrostatic interactions into chitosan scaffolds produced by freeze-drying with approx. 100 ?m pore diameter. According to the ICP-OES results, following first 5h initial burst release, fast release of B from scaffolds was observed for 24h incubation period in conditioned medium. Then, slow release of B was performed over 120 h. The results of the cell culture studies proved that the encapsulated boron within the scaffolds can be used as an osteoinductive agent by showing its positive effects on the proliferation and differentiation of MC3T3-E1 preosteoblastic cells. PMID:26004902

  18. Polymeric nanoparticles

    PubMed Central

    Bolhassani, Azam; Javanzad, Shabnam; Saleh, Tayebeh; Hashemi, Mehrdad; Aghasadeghi, Mohammad Reza; Sadat, Seyed Mehdi

    2014-01-01

    Nanocarriers with various compositions and biological properties have been extensively applied for in vitro/in vivo drug and gene delivery. The family of nanocarriers includes polymeric nanoparticles, lipid-based carriers (liposomes/micelles), dendrimers, carbon nanotubes, and gold nanoparticles (nanoshells/nanocages). Among different delivery systems, polymeric carriers have several properties such as: easy to synthesize, inexpensive, biocompatible, biodegradable, non-immunogenic, non-toxic, and water soluble. In addition, cationic polymers seem to produce more stable complexes led to a more protection during cellular trafficking than cationic lipids. Nanoparticles often show significant adjuvant effects in vaccine delivery since they may be easily taken up by antigen presenting cells (APCs). Natural polymers such as polysaccharides and synthetic polymers have demonstrated great potential to form vaccine nanoparticles. The development of new adjuvants or delivery systems for DNA and protein immunization is an expanding research field. This review describes polymeric carriers especially PLGA, chitosan, and PEI as vaccine delivery systems. PMID:24128651

  19. Development of channeled nanofibrous scaffolds for oriented tissue engineering

    PubMed Central

    Sun, Chenghui; Jin, Xiaobing; Holzwarth, Jeremy M.; Liu, Xiaohua; Hu, Jiang; Gupte, Melanie J.; Zhao, Yaoming; Ma, Peter X

    2013-01-01

    A tissue-engineering scaffold resembling the characteristic structure of the natural extracellular matrix can often facilitate tissue regeneration. Nerve and tendon are oriented micro-scale sheathed tissue bundles. In this study, a method combining injection molding and thermally induced phase separation techniques was developed to create single- and multiple-channeled nanofibrous (NF) poly(L-lactic acid) scaffolds. The overall shape, the number and arrangement of channels, and the channel wall matrix architecture of the scaffolds were tailored by altering the configuration of the mold assembly and the phase separation conditions. The porosity and mechanical properties of the scaffolds were tailored by varying the concentration of the polymer solution used. The porous NF channel wall matrix provided a beneficial luminal microenvironment that increased protein adsorption and promoted the attachment of PC12 rat neuronal cells and rabbit patellar tendon fibroblast cells, showing potential for neural and tendon tissue regeneration. PMID:22508530

  20. Micropatterning electrospun scaffolds to create intrinsic vascular networks.

    PubMed

    Jeffries, Eric M; Nakamura, Shintaro; Lee, Kee-Won; Clampffer, Jimmy; Ijima, Hiroyuki; Wang, Yadong

    2014-11-01

    Sufficient vascularization is critical to sustaining viable tissue-engineered (TE) constructs after implantation. Despite significant progress, current approaches lack suturability, porosity, and biodegradability, which hinders rapid perfusion and remodeling in vivo. Consequently, TE vascular networks capable of direct anastomosis to host vasculature and immediate perfusion upon implantation still remain elusive. Here, a hybrid fabrication method is presented for micropatterning fibrous scaffolds that are suturable, porous, and biodegradable. Fused deposition modeling offers an inexpensive and automated approach to creating sacrificial templates with vascular-like branching. By electrospinning around these poly(vinyl alcohol) templates and dissolving them in water, microvascular patterns were transferred to fibrous scaffolds. Results indicated that these scaffolds have sufficient suture retention strength to permit direct anastomosis in future studies. Vascularization of these scaffolds is demonstrated by in vitro endothelialization and perfusion. PMID:25142314

  1. Synthesis and characterization of nanocrystalline forsterite coated poly(L-lactide-co-?-malic acid) scaffolds for bone tissue engineering applications.

    PubMed

    Mozafari, M; Gholipourmalekabadi, M; Chauhan, N P S; Jalali, N; Asgari, S; Caicedoa, J C; Hamlekhan, A; Urbanska, A M

    2015-05-01

    In this research, after synthesizing poly(L-lactide-co-?-malic acid) (PLMA) copolymer, hybrid particles of ice and nanocrystalline forsterite (NF) as coating carriers were used to prepare NF-coated PLMA scaffolds. The porous NF-coated scaffolds were directly fabricated by a combined technique using porogen leaching and freeze-drying methods. The obtained results indicate that the scaffolds were structurally porous with NF particles on their surfaces. When compared to the uncoated scaffolds, the NF coating improved both mechanical properties as well as enhanced bioactivity of the scaffolds. In addition, in vitro biological response of the rat bone marrow stromal cells indicated that NF significantly increased the biocompatibility of NF-coated scaffolds compared with PLMA. PMID:25746252

  2. Osteogenic cell response to 3-D hydroxyapatite scaffolds developed via replication of natural marine sponges.

    PubMed

    Clarke, S A; Choi, S Y; McKechnie, Melanie; Burke, G; Dunne, N; Walker, G; Cunningham, E; Buchanan, F

    2016-02-01

    Bone tissue engineering may provide an alternative to autograft, however scaffold optimisation is required to maximize bone ingrowth. In designing scaffolds, pore architecture is important and there is evidence that cells prefer a degree of non-uniformity. The aim of this study was to compare scaffolds derived from a natural porous marine sponge (Spongia agaricina) with unique architecture to those derived from a synthetic polyurethane foam. Hydroxyapatite scaffolds of 1 cm(3) were prepared via ceramic infiltration of a marine sponge and a polyurethane (PU) foam. Human foetal osteoblasts (hFOB) were seeded at 1 × 10(5) cells/scaffold for up to 14 days. Cytotoxicity, cell number, morphology and differentiation were investigated. PU-derived scaffolds had 84-91 % porosity and 99.99 % pore interconnectivity. In comparison marine sponge-derived scaffolds had 56-61 % porosity and 99.9 % pore interconnectivity. hFOB studies showed that a greater number of cells were found on marine sponge-derived scaffolds at than on the PU scaffold but there was no significant difference in cell differentiation. X-ray diffraction and inductively coupled plasma mass spectrometry showed that Si ions were released from the marine-derived scaffold. In summary, three dimensional porous constructs have been manufactured that support cell attachment, proliferation and differentiation but significantly more cells were seen on marine-derived scaffolds. This could be due both to the chemistry and pore architecture of the scaffolds with an additional biological stimulus from presence of Si ions. Further in vivo tests in orthotopic models are required but this marine-derived scaffold shows promise for applications in bone tissue engineering. PMID:26704539

  3. Sol–gel method to fabricate CaP scaffolds by robocasting for tissue engineering

    PubMed Central

    Fu, Qiang; Saiz, Eduardo; Tomsia, Antoni P.

    2012-01-01

    Highly porous calcium phosphate (CaP) scaffolds for bone-tissue engineering were fabricated by combining a robocasting process with a sol–gel synthesis that mixed Calcium Nitrate Tetrahydrate and Triethyl Phosphite precursors in an aqueous medium. The resulting gels were used to print scaffolds by robocasting without the use of binder to increase the viscosity of the paste. X-ray diffraction analysis confirmed that the process yielded hydroxyapatite and ?-tricalcium phosphate biphasic composite powders. Thus, the scaffold composition after crystallization of the amorphous structure could be easily modified by varying the initial Ca/P ratio during synthesis. The compressive strengths of the scaffolds are ~6 MPa, which is in the range of human cancellous bone (2–12 MPa). These highly porous scaffolds (~73 vol% porosity) are composed of macro-pores of ~260 ?m in size; such porosity is expected to enable bone ingrowth into the scaffold for bone repair applications. The chemistry, porosity, and surface topography of such scaffolds can also be modified by the process parameters to favor bone formation. The studied sol–gel process can be used to coat these scaffolds by dip-coating, which induces a significant enhancement of mechanical properties. This can adjust scaffold properties such as composition and surface morphology, which consequently may improve their performances. PMID:22311079

  4. Small, porous polyacrylate beads

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping Siao (Inventor); Dreyer, William J. (Inventor)

    1976-01-01

    Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

  5. Polycaprolactone nanofiber interspersed collagen type-I scaffold for bone regeneration: a unique injectable osteogenic scaffold.

    PubMed

    Baylan, Nuray; Bhat, Samerna; Ditto, Maggie; Lawrence, Joseph G; Lecka-Czernik, Beata; Yildirim-Ayan, Eda

    2013-08-01

    There is an increasing demand for an injectable cell coupled three-dimensional (3D) scaffold to be used as bone fracture augmentation material. To address this demand, a novel injectable osteogenic scaffold called PN-COL was developed using cells, a natural polymer (collagen type-I), and a synthetic polymer (polycaprolactone (PCL)). The injectable nanofibrous PN-COL is created by interspersing PCL nanofibers within pre-osteoblast cell embedded collagen type-I. This simple yet novel and powerful approach provides a great benefit as an injectable bone scaffold over other non-living bone fracture stabilization polymers, such as polymethylmethacrylate and calcium content resin-based materials. The advantages of injectability and the biomimicry of collagen was coupled with the structural support of PCL nanofibers, to create cell encapsulated injectable 3D bone scaffolds with intricate porous internal architecture and high osteoconductivity. The effects of PCL nanofiber inclusion within the cell encapsulated collagen matrix has been evaluated for scaffold size retention and osteocompatibility, as well as for MC3T3-E1 cells osteogenic activity. The structural analysis of novel bioactive material proved that the material is chemically stable enough in an aqueous solution for an extended period of time without using crosslinking reagents, but it is also viscous enough to be injected through a syringe needle. Data from long-term in vitro proliferation and differentiation data suggests that novel PN-COL scaffolds promote the osteoblast proliferation, phenotype expression, and formation of mineralized matrix. This study demonstrates for the first time the feasibility of creating a structurally competent, injectable, cell embedded bone tissue scaffold. Furthermore, the results demonstrate the advantages of mimicking the hierarchical architecture of native bone with nano- and micro-size formation through introducing PCL nanofibers within macron-size collagen fibers and in promoting osteoblast phenotype progression for bone regeneration. PMID:23804651

  6. The effect of autologous bone marrow stromal cells differentiated on scaffolds for canine tibial bone reconstruction.

    PubMed

    Özdal-Kurt, F; Tu?lu, I; Vatansever, H S; Tong, S; Delilo?lu-Gürhan, S I

    2015-10-01

    Bone marrow contains mesenchymal stem cells that form many tissues. Various scaffolds are available for bone reconstruction by tissue engineering. Osteoblastic differentiated bone marrow stromal cells (BMSC) promote osteogenesis on scaffolds and stimulate bone regeneration. We investigated the use of cultured autologous BMSC on different scaffolds for healing defects in tibias of adult male canines. BMSC were isolated from canine humerus bone marrow, differentiated into osteoblasts in culture and loaded onto porous ceramic scaffolds including hydroxyapatite 1, hydroxyapatite gel and calcium phosphate. Osteoblast differentiation was verified by osteonectine and osteocalcine immunocytochemistry. The scaffolds with stromal cells were implanted in the tibial defect. Scaffolds without stromal cells were used as controls. Sections from the defects were processed for histological, ultrastructural, immunohistochemical and histomorphometric analyses to analyze the healing of the defects. BMSC were spread, allowed to proliferate and differentiate to osteoblasts as shown by alizarin red histochemistry, and osteocalcine and osteonectine immunostaining. Scanning electron microscopy showed that BMSC on the scaffolds were more active and adhesive to the calcium phosphate scaffold compared to the others. Macroscopic bone formation was observed in all groups, but scaffolds with stromal cells produced significantly better results. Bone healing occurred earlier and faster with stromal cells on the calcium phosphate scaffold and produced more callus compared to other scaffolds. Tissue healing and osteoblastic marker expression also were better with stromal cells on the scaffolds. Increased trabecula formation, cell density and decreased fibrosis were observed in the calcium phosphate scaffold with stromal cells. Autologous cultured stromal cells on the scaffolds were useful for healing of canine tibial bone defects. The calcium phosphate scaffold was the best for both cell differentiation in vitro and bone regeneration in vivo. It may be possible to improve healing of bone defects in humans using stem cells from bone marrow. PMID:25994048

  7. Biocompatibility and osteogenesis of biomimetic Bioglass-Collagen-Phosphatidylserine composite scaffolds for bone tissue engineering.

    PubMed

    Xu, Caixia; Su, Peiqiang; Chen, Xiaofeng; Meng, Yongchun; Yu, Weihua; Xiang, Andy Peng; Wang, Yingjun

    2011-02-01

    A novel biomimetic composite scaffold Bioglass-Collagen-Phosphatidylserine (BG-COL-PS) was fabricated with a freeze-drying technique. The macrostructure and morphology as well as mechanical strength of the scaffolds were characterized. Scanning electronic microscopy (SEM) showed that the BG-COL-PS scaffolds exhibited interconnected porous structures with pore sizes of several microns up to about 300 ?m. The scaffolds have a porosity of 75.40% and the corresponding compressive strength of 1.5469 Mpa. Rat mesenchymal stem cells (rMSCs) were seeded on BG-COL-PS or BG-COL scaffolds and cultured for 21 days in vitro. Based on the results of SEM, dsDNA content, alkaline phosphatase (ALP) activity, osteogenic gene expression analysis and alizarin red staining, the responses of MSCs to the scaffold exhibited a higher degree of attachment, growth as well as osteogenic differentiation than those on BG-COL scaffolds in vitro. To investigate the in vivo biocompatibility and osteogenesis of the composite scaffolds, both pure BG-COL-PS scaffolds and MSC/scaffold constructs were implanted in rat femurs defects for 6 weeks and studied histologically and radiographically. The in vivo results showed that BG-COL-PS composite scaffolds exhibited good biocompatibility and extensive osteoconductivity with host bone. Moreover, the BG-COL-PS/MSC constructs dramatically enhanced the efficiency of new bone formation than pure BG-COL-PS scaffolds or BG-COL/MSC constructs. All these results demonstrate the usefulness of PS composited BG-COL-PS scaffolds for inducing enhanced bone formation. The BG-COL-PS scaffolds fulfill the basic requirements of bone tissue engineering scaffold and have the potential to be applied in orthopedic and reconstructive surgery. PMID:20980051

  8. [Influencing Factors on the Properties of Bone Scaffolds and Their Manufacturing Techniques].

    PubMed

    Zhang, Yingying; Gong, He

    2015-04-01

    To serve as carriers of cells and bioactive molecules, three-dimensional scaffolds play a key role in bone defect repair. The chemical component and microstructure of the scaffold can affect the mechanical properties and seed cells. A variety of fabrication techniques have been used in producing scaffolds, some made random porous structure, some created well-designed structure using rapid prototyping methods, and others prepared bio-derived materials as scaffolds. However, scaffolds may vary in their inner structure, mechanical properties and repairing efficiency as well because of different manufacturing methods. In this review, we overview the main achievements concerning the effects of material and microstructure on the mechanical performance, seed cells and defect repair of bone scaffolds. PMID:26211276

  9. Chitosan scaffolds containing chicken feather keratin nanoparticles for bone tissue engineering.

    PubMed

    Saravanan, S; Sameera, D K; Moorthi, A; Selvamurugan, N

    2013-11-01

    Chicken feathers are considered as major waste from poultry industry. They are mostly constituted by a protein called keratin. In this study, keratin was prepared from chicken feathers and from where keratin nanoparticles (nKer) were synthesized. Since chitosan has excellent properties like controlled biodegradation and biocompatibility, we used keratin nanoparticles along with chitosan matrix as scaffolds (CS/nKer) and they were characterized by SEM, FT-IR and XRD analyses. There was a porous architecture in the scaffolds in the range to support cell infiltration and tissue ingrowth. The keratin nanoparticles had interaction with chitosan matrix and did not alter the semi crystalline nature of chitosan scaffolds. The biodegradation and protein adsorption of the scaffolds were significantly increased upon addition of keratin nanoparticles. The scaffolds were also found to be non-cytotoxic to human osteoblastic cells. Thus, CS/nKer scaffolds could serve as a potential biomimetic substrate for bone tissue engineering applications. PMID:24095711

  10. Nano-Fibrous Tissue Engineering Scaffolds Capable of Growth Factor Delivery

    PubMed Central

    Hu, Jiang

    2011-01-01

    Tissue engineering aims at constructing biological substitutes to repair damaged tissues. Three-dimensional (3D) porous scaffolds are commonly utilized to define the 3D geometry of tissue engineering constructs and provide adequate pore space and surface to support cell attachment, migration, proliferation, differentiation and neo tissue genesis. Biomimetic 3D scaffolds provide synthetic microenvironments that mimic the natural regeneration microenvironments and promote tissue regeneration process. While nano-fibrous (NF) scaffolds are constructed to mimic the architecture of NF extracellular matrix, controlled-release growth factors are incorporated to modulate the regeneration process. The present article summarizes current advances in methods to fabricate NF polymer scaffolds and the technologies to incorporate controlled growth factor delivery systems into 3D scaffolds, followed by examples of accelerated regeneration when the scaffolds with growth factor releasing capacity are applied in animal models. PMID:21234657

  11. Synthesis of Macroporous Poly(dimethylsiloxane) Scaffolds for Tissue Engineering Applications

    PubMed Central

    Pedraza, Eileen; Brady, Ann-Christina; Fraker, Christopher A.

    2015-01-01

    Macroporous, biostable scaffolds with controlled porous architecture were prepared from poly(dimethylsiloxane) (PDMS) using sodium chloride particles (NaCl) and a solvent casting and particulate leaching (SCPL) technique. The effect of particulate size range and overall porosity on the resulting structure was evaluated. Results found 90% v/v scaffolds and particulate ranges above 100 µm to have the most optimal open framework and porosity. Resulting hydrophobic PDMS scaffolds were coated with fibronectin and evaluated as a platform for adherent cell culture using human mesenchymal stem cells. Biocompatibility of PDMS scaffolds was also evaluated in a rodent model, where implants were found to be highly biocompatibile and biostable, with positive extracellular matrix deposition throughout the scaffold. These results demonstrate the suitability of macroporous PDMS scaffolds for tissue engineering applications where strong integration with the host is desired. PMID:23683037

  12. Imaging studies of peripheral nerve regeneration induced by porous collagen biomaterials

    E-print Network

    Tzeranis, Dimitrios Spyridon

    2013-01-01

    There is urgent need to develop treatments for inducing regeneration in injured organs. Porous collagen-based scaffolds have been utilized clinically to induce regeneration in skin and peripheral nerves, however still there ...

  13. Solvent-free polymer/bioceramic scaffolds for bone tissue engineering: fabrication, analysis, and cell growth.

    PubMed

    Minton, Joshua; Janney, Cara; Akbarzadeh, Rosa; Focke, Carlie; Subramanian, Aswati; Smith, Tyler; McKinney, Joseph; Liu, Junyi; Schmitz, James; James, Paul F; Yousefi, Azizeh-Mitra

    2014-01-01

    This study examines the potential use of porous polycaprolactone (PCL) and polycaprolocatone/hydroxyapatite (PCL/HA) scaffolds fabricated through melt molding and porogen leaching for bone tissue engineering. While eliminating organic solvents is desirable, the process steps proposed in this study for uniformly dispersing HA particles (~5??m in size) within the scaffold can also contribute to homogeneous properties for these porous composites. Poly(ethylene oxide) (PEO) was chosen as a porogen due to its similar density and melting point as PCL. Pore size of the scaffold was controlled by limiting the size of PCL and PEO particles used in fabrication. The percent of HA in the fabricated scaffolds was quantified by thermogravimetric analysis (TGA). Mechanical testing was used to compare the modulus of the scaffolds to that of bone, and the pore size distribution was examined with microcomputed tomography (?CT). Scanning electron microscopy (SEM) was used to examine the effect on scaffold morphology caused by the addition of HA particles. Both ?CT and SEM results showed that HA could be incorporated into PCL scaffolds without negatively affecting scaffold morphology or pore formation. Energy-dispersive X-ray spectroscopy (EDS) and elemental mapping demonstrated a uniform distribution of HA within PCL/HA scaffolds. Murine calvaria-derived MC3T3-E1 cells were used to determine whether cells could attach on scaffolds and grow for up to 21 days. SEM images revealed an increase in cell attachment with the incorporation of HA into the scaffolds. Similarly, DNA content analysis showed a higher cell adhesion to PCL/HA scaffolds. PMID:25178801

  14. Biomimetic materials and scaffolds for myocardial tissue regeneration.

    PubMed

    Silvestri, Antonella; Boffito, Monica; Sartori, Susanna; Ciardelli, Gianluca

    2013-08-01

    One of the main challenges in tissue engineering/regenerative medicine (TERM) is the repair of damaged heart tissue, avoiding or minimizing ventricular remodeling which leads to ventricular dilatation and hypertrophy, sphericity increase, and functionality loss. Several approaches have been described to restore or enhance the contractility of the failing heart. One of them is based on the fabrication of 3D substrates that can be implanted in the infarcted area to provide an efficient support to the regenerative process. This review focuses on the strategies adopted to design and realize polymeric scaffolds for heart TERM. The implementation of different polymers and the design of scaffold architecture are described. PMID:23836778

  15. Scaffold-based Drug Delivery for Cartilage Tissue Regeneration.

    PubMed

    Shalumon, K T; Chen, Jyh-Ping

    2015-01-01

    Regenerative engineering is an advanced field comprising the collective benefit of biodegradable polymers with cells and tissue inducing factors. Current method of replacing the defective organ is through transplantation, but is limited due to immune rejection and availability. As a solution, new polymeric biomaterial-based three-dimensional (3D) scaffolds in combination with cells and inducing factors were aroused to fulfil the existing demands. These scaffolds apply material science, biomedical technology and translational medicine to develop functional tissue engineering constructs. Presence of small molecules and growth factors guides the cell phenotypes to specific organ development. The 3D scaffold thus could also be favorably used as carriers for various types of drugs and genes, with the release profile fine-tuned by modulation of the scaffold's morphology, porosity, and composition. An increasing trend was observed in recent years toward the combination of scaffolds and growth factors to fabricate a bioactive system, which not only provide a biomimetic biodegradable physical support for tissue growth but also explores biological signals to modulate tissue regeneration. In this review, along with general aspects of tissue engineering, we also discuss the importance of various scaffold architectures like nanofibers, hydrogels, beads, meshes, microspheres etc. in combination with specific drugs, growth factors and small molecules for cartilage regeneration. Growth factors may be incorporated into scaffolds by direct blending, physical adsorption, drop casting, surface grafting, covalent bonding, chemical immobilization, coaxial electrospinning, microparticle incorporation etc. This offers new possibilities for the development of biomimetic scaffolds that are endowed with a hierarchical architecture and sophisticated release kinetics of the growth factors. This review portrait the fundamentals of tissue engineering with emphasis on the role of inducing factors in scaffold based cartilage tissue regeneration. PMID:25732662

  16. Novel Polypyrrole-Coated Polylactide Scaffolds Enhance Adipose Stem Cell Proliferation and Early Osteogenic Differentiation

    PubMed Central

    Pelto, Jani; Björninen, Miina; Pälli, Aliisa; Talvitie, Elina; Hyttinen, Jari; Mannerström, Bettina; Suuronen Seppanen, Riitta; Kellomäki, Minna; Miettinen, Susanna; Haimi, Suvi

    2013-01-01

    An electrically conductive polypyrrole (PPy) doped with a bioactive agent is an emerging functional biomaterial for tissue engineering. We therefore used chondroitin sulfate (CS)-doped PPy coating to modify initially electrically insulating polylactide resulting in novel osteogenic scaffolds. In situ chemical oxidative polymerization was used to obtain electrically conductive PPy coating on poly-96L/4D-lactide (PLA) nonwoven scaffolds. The coated scaffolds were characterized and their electrical conductivity was evaluated in hydrolysis. The ability of the coated and conductive scaffolds to enhance proliferation and osteogenic differentiation of human adipose stem cells (hASCs) under electrical stimulation (ES) in three-dimensional (3D) geometry was compared to the noncoated PLA scaffolds. Electrical conductivity of PPy-coated PLA scaffolds (PLA-PPy) was evident at the beginning of hydrolysis, but decreased during the first week of incubation due to de-doping. PLA-PPy scaffolds enhanced hASC proliferation significantly compared to the plain PLA scaffolds at 7 and 14 days. Furthermore, the alkaline phosphatase (ALP) activity of the hASCs was generally higher in PLA-PPy seeded scaffolds, but due to patient variation, no statistical significance could be determined. ES did not have a significant effect on hASCs. This study highlights the potential of novel PPy-coated PLA scaffolds in bone tissue engineering. PMID:23126228

  17. Bioactive scaffold for bone tissue engineering: An in vivo study

    NASA Astrophysics Data System (ADS)

    Livingston, Treena Lynne

    Massive bone loss of the proximal femur is a common problem in revision cases of total hip implants. Allograft is typically used to reconstruct the site for insertion of the new prosthesis. However, for long term fixation and function, it is desirable that the allograft becomes fully replaced by bone tissue and aids in the regeneration of bone to that site. However, allograft use is typically associated with delayed incorporation and poor remodeling. Due to these profound limitations, alternative approaches are needed. Tissue engineering is an attractive approach to designing improved graft materials. By combining osteogenic activity with a resorbable scaffold, bone formation can be stimulated while providing structure and stability to the limb during incorporation and remodeling of the scaffold. Porous, surface modified bioactive ceramic scaffolds (pSMC) have been developed which stimulate the expression of the osteoblastic phenotype and production of bone-like tissue in vitro. The scaffold and two tissue-engineered constructs, osteoprogenitor cells seeded onto scaffolds or cells expanded in culture to form bone tissue on the scaffolds prior to implantation, were investigated in a long bone defect model. The rate of incorporation was assessed. Both tissue-engineered constructs stimulated bone formation and comparable repair at 2 weeks. In a rat femoral window defect model, bone formation increased over time for all groups in concert with scaffold resorption, leading to a 40% increase in bone and 40% reduction of the scaffold in the defect by 12 weeks. Both tissue-engineered constructs enhanced the rate of mechanical repair of long bones due to better bony union with the host cortex. Long bones treated with tissue engineered constructs demonstrated a return in normal torsional properties by 4 weeks as compared to 12 weeks for long bones treated with pSMC. Culture expansion of cells to produce bone tissue in vitro did not accelerate incorporation over the treatment with cells seeded at the time of surgery. Porous, surface modified bioactive ceramic is a promising scaffold material for tissue-engineered bone repair. Bone formation and scaffold resorption act in concert for maintenance and improvement of the structural properties of the long bones over time. As determined histomorphometrically and mechanically, the rate of incorporation of the scaffold was enhanced with the tissue-engineered constructs.

  18. Evaluating changes in structure and cytotoxicity during in vitro degradation of three-dimensional printed scaffolds.

    PubMed

    Wang, Martha O; Piard, Charlotte M; Melchiorri, Anthony; Dreher, Maureen L; Fisher, John P

    2015-05-01

    This study evaluated the structural, mechanical, and cytocompatibility changes of three-dimensional (3D) printed porous polymer scaffolds during degradation. Three porous scaffold designs were fabricated from a poly(propylene fumarate) (PPF) resin. PPF is a hydrolytically degradable polymer that has been well characterized for applications in bone tissue engineering. Over a 224 day period, scaffolds were hydrolytically degraded and changes in scaffold parameters, such as porosity and pore size, were measured nondestructively using micro-computed tomography. In addition, changes in scaffold mechanical properties were also measured during degradation. Scaffold degradation was verified through decreasing pH and increasing mass loss as well as the formation of micropores and surface channels. Current methods to evaluate polymer cytotoxicity have been well established; however, the ability to evaluate toxicity of an absorbable polymer as it degrades has not been well explored. This study, therefore, also proposes a novel method to evaluate the cytotoxicity of the absorbable scaffolds using a combination of degradation extract, phosphate-buffered saline, and cell culture media. Fibroblasts were incubated with this combination media, and cytotoxicity was evaluated using XTT assay and fluorescence imaging. Cell culture testing demonstrated that the 3D-printed scaffold extracts did not induce significant cell death. In addition, results showed that over a 224 day time period, porous PPF scaffolds provided mechanical stability while degrading. Overall, these results show that degradable, 3D-printed PPF scaffolds are suitable for bone tissue engineering through the use of a novel toxicity during degradation assay. PMID:25627168

  19. Fabrication and in vitro biocompatibility of biomorphic PLGA/nHA composite scaffolds for bone tissue engineering.

    PubMed

    Qian, Junmin; Xu, Weijun; Yong, Xueqing; Jin, Xinxia; Zhang, Wei

    2014-03-01

    In this study, biomorphic poly(dl-lactic-co-glycolic acid)/nano-hydroxyapatite (PLGA/nHA) composite scaffolds were successfully prepared using cane as a template. The porous morphology, phase, compression characteristics and in vitro biocompatibility of the PLGA/nHA composite scaffolds and biomorphic PLGA scaffolds as control were investigated. The results showed that the biomorphic scaffolds preserved the original honeycomb-like architecture of cane and exhibited a bimodal porous structure. The average channel diameter and micropore size of the PLGA/nHA composite scaffolds were 164 ± 52 ?m and 13 ± 8 ?m, respectively, with a porosity of 89.3 ± 1.4%. The incorporation of nHA into PLGA decreased the degree of crystallinity of PLGA, and significantly improved the compressive modulus of biomorphic scaffolds. The in vitro biocompatibility evaluation with MC3T3-E1 cells demonstrated that the biomorphic PLGA/nHA composite scaffolds could better support cell attachment, proliferation and differentiation than the biomorphic PLGA scaffolds. The localization depth of MC3T3-E1 cells within the channels of the biomorphic PLGA/nHA composite scaffolds could reach approximately 400 ?m. The results suggested that the biomorphic PLGA/nHA composite scaffolds were promising candidates for bone tissue engineering. PMID:24433891

  20. Three-Dimensional Printing of Hollow-Struts-Packed Bioceramic Scaffolds for Bone Regeneration.

    PubMed

    Luo, Yongxiang; Zhai, Dong; Huan, Zhiguang; Zhu, Haibo; Xia, Lunguo; Chang, Jiang; Wu, Chengtie

    2015-11-01

    Three-dimensional printing technologies have shown distinct advantages to create porous scaffolds with designed macropores for application in bone tissue engineering. However, until now, 3D-printed bioceramic scaffolds only possessing a single type of macropore have been reported. Generally, those scaffolds with a single type of macropore have relatively low porosity and pore surfaces, limited delivery of oxygen and nutrition to surviving cells, and new bone tissue formation in the center of the scaffolds. Therefore, in this work, we present a useful and facile method for preparing hollow-struts-packed (HSP) bioceramic scaffolds with designed macropores and multioriented hollow channels via a modified coaxial 3D printing strategy. The prepared HSP scaffolds combined high porosity and surface area with impressive mechanical strength. The unique hollow-struts structures of bioceramic scaffolds significantly improved cell attachment and proliferation and further promoted formation of new bone tissue in the center of the scaffolds, indicating that HSP ceramic scaffolds can be used for regeneration of large bone defects. In addition, the strategy can be used to prepare other HSP ceramic scaffolds, indicating a universal application for tissue engineering, mechanical engineering, catalysis, and environmental materials. PMID:26479454

  1. A Novel Albumin-Based Tissue Scaffold for Autogenic Tissue Engineering Applications

    NASA Astrophysics Data System (ADS)

    Li, Pei-Shan; -Liang Lee, I.; Yu, Wei-Lin; Sun, Jui-Sheng; Jane, Wann-Neng; Shen, Hsin-Hsin

    2014-07-01

    Tissue scaffolds provide a framework for living tissue regeneration. However, traditional tissue scaffolds are exogenous, composed of metals, ceramics, polymers, and animal tissues, and have a defined biocompatibility and application. This study presents a new method for obtaining a tissue scaffold from blood albumin, the major protein in mammalian blood. Human, bovine, and porcine albumin was polymerised into albumin polymers by microbial transglutaminase and was then cast by freeze-drying-based moulding to form albumin tissue scaffolds. Scanning electron microscopy and material testing analyses revealed that the albumin tissue scaffold possesses an extremely porous structure, moderate mechanical strength, and resilience. Using a culture of human mesenchymal stem cells (MSCs) as a model, we showed that MSCs can be seeded and grown in the albumin tissue scaffold. Furthermore, the albumin tissue scaffold can support the long-term osteogenic differentiation of MSCs. These results show that the albumin tissue scaffold exhibits favourable material properties and good compatibility with cells. We propose that this novel tissue scaffold can satisfy essential needs in tissue engineering as a general-purpose substrate. The use of this scaffold could lead to the development of new methods of artificial fabrication of autogenic tissue substitutes.

  2. Three-Dimensional Scaffolds for Tissue Engineering Applications: Role of Porosity and Pore Size

    PubMed Central

    Loh, Qiu Li

    2013-01-01

    Tissue engineering applications commonly encompass the use of three-dimensional (3D) scaffolds to provide a suitable microenvironment for the incorporation of cells or growth factors to regenerate damaged tissues or organs. These scaffolds serve to mimic the actual in vivo microenvironment where cells interact and behave according to the mechanical cues obtained from the surrounding 3D environment. Hence, the material properties of the scaffolds are vital in determining cellular response and fate. These 3D scaffolds are generally highly porous with interconnected pore networks to facilitate nutrient and oxygen diffusion and waste removal. This review focuses on the various fabrication techniques (e.g., conventional and rapid prototyping methods) that have been employed to fabricate 3D scaffolds of different pore sizes and porosity. The different pore size and porosity measurement methods will also be discussed. Scaffolds with graded porosity have also been studied for their ability to better represent the actual in vivo situation where cells are exposed to layers of different tissues with varying properties. In addition, the ability of pore size and porosity of scaffolds to direct cellular responses and alter the mechanical properties of scaffolds will be reviewed, followed by a look at nature's own scaffold, the extracellular matrix. Overall, the limitations of current scaffold fabrication approaches for tissue engineering applications and some novel and promising alternatives will be highlighted. PMID:23672709

  3. Three-dimensional scaffolds for tissue engineering applications: role of porosity and pore size.

    PubMed

    Loh, Qiu Li; Choong, Cleo

    2013-12-01

    Tissue engineering applications commonly encompass the use of three-dimensional (3D) scaffolds to provide a suitable microenvironment for the incorporation of cells or growth factors to regenerate damaged tissues or organs. These scaffolds serve to mimic the actual in vivo microenvironment where cells interact and behave according to the mechanical cues obtained from the surrounding 3D environment. Hence, the material properties of the scaffolds are vital in determining cellular response and fate. These 3D scaffolds are generally highly porous with interconnected pore networks to facilitate nutrient and oxygen diffusion and waste removal. This review focuses on the various fabrication techniques (e.g., conventional and rapid prototyping methods) that have been employed to fabricate 3D scaffolds of different pore sizes and porosity. The different pore size and porosity measurement methods will also be discussed. Scaffolds with graded porosity have also been studied for their ability to better represent the actual in vivo situation where cells are exposed to layers of different tissues with varying properties. In addition, the ability of pore size and porosity of scaffolds to direct cellular responses and alter the mechanical properties of scaffolds will be reviewed, followed by a look at nature's own scaffold, the extracellular matrix. Overall, the limitations of current scaffold fabrication approaches for tissue engineering applications and some novel and promising alternatives will be highlighted. PMID:23672709

  4. Polymeric Nanofibers in Tissue Engineering

    PubMed Central

    Dahlin, Rebecca L.; Kasper, F. Kurtis

    2011-01-01

    Polymeric nanofibers can be produced using methods such as electrospinning, phase separation, and self-assembly, and the fiber composition, diameter, alignment, degradation, and mechanical properties can be tailored to the intended application. Nanofibers possess unique advantages for tissue engineering. The small diameter closely matches that of extracellular matrix fibers, and the relatively large surface area is beneficial for cell attachment and bioactive factor loading. This review will update the reader on the aspects of nanofiber fabrication and characterization important to tissue engineering, including control of porous structure, cell infiltration, and fiber degradation. Bioactive factor loading will be discussed with specific relevance to tissue engineering. Finally, applications of polymeric nanofibers in the fields of bone, cartilage, ligament and tendon, cardiovascular, and neural tissue engineering will be reviewed. PMID:21699434

  5. Woven silk fabric-reinforced silk nanofibrous scaffolds for regenerating load-bearing soft tissues.

    PubMed

    Han, F; Liu, S; Liu, X; Pei, Y; Bai, S; Zhao, H; Lu, Q; Ma, F; Kaplan, D L; Zhu, H

    2014-02-01

    Although three-dimensional (3-D) porous regenerated silk scaffolds with outstanding biocompatibility, biodegradability and low inflammatory reactions have promising application in different tissue regeneration, the mechanical properties of regenerated scaffolds, especially suture retention strength, must be further improved to satisfy the requirements of clinical applications. This study presents woven silk fabric-reinforced silk nanofibrous scaffolds aimed at dermal tissue engineering. To improve the mechanical properties, silk scaffolds prepared by lyophilization were reinforced with degummed woven silk fabrics. The ultimate tensile strength, elongation at break and suture retention strength of the scaffolds were significantly improved, providing suitable mechanical properties strong enough for clinical applications. The stiffness and degradation behaviors were then further regulated by different after-treatment processes, making the scaffolds more suitable for dermal tissue regeneration. The in vitro cell culture results indicated that these scaffolds maintained their excellent biocompatibility after being reinforced with woven silk fabrics. Without sacrifice of porous structure and biocompatibility, the fabric-reinforced scaffolds with better mechanical properties could facilitate future clinical applications of silk as matrices in skin repair. PMID:24090985

  6. 3D Tissue Scaffolds BIOMATERIALS

    E-print Network

    properties. The platform encompasses several major classes of scaffolds including salt-leached scaffolds for assessing the impact of the physical and chemical properties of 3D tissue scaffolds on cellular response) that will enable companies to reliably characterize physical properties of their scaffold-based products. · We have

  7. Ionene modified small polymeric beads

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1977-01-01

    Linear ionene polyquaternary cationic polymeric segments are bonded by means of the Menshutkin reaction (quaternization) to biocompatible, extremely small, porous particles containing halide or tertiary amine sites which are centers for attachment of the segments. The modified beads in the form of emulsions or suspensions offer a large, positively-charged surface area capable of irreversibly binding polyanions such as heparin, DNA, RNA or bile acids to remove them from solution or of reversibly binding monoanions such as penicillin, pesticides, sex attractants and the like for slow release from the suspension.

  8. Chain Reaction Polymerization.

    ERIC Educational Resources Information Center

    McGrath, James E.

    1981-01-01

    The salient features and importance of chain-reaction polymerization are discussed, including such topics as the thermodynamics of polymerization, free-radical polymerization kinetics, radical polymerization processes, copolymers, and free-radical chain, anionic, cationic, coordination, and ring-opening polymerizations. (JN)

  9. Chitosan/bioactive glass nanoparticles scaffolds with shape memory properties.

    PubMed

    Correia, Cristina O; Leite, Álvaro J; Mano, João F

    2015-06-01

    We propose a combination of chitosan (CHT) with bioactive glass nanoparticles (BG-NPs) in order to produce CHT/BG-NPs scaffolds that combine the shape memory properties of chitosan and the biomineralization ability of BG-NPs for applications in bone regeneration. The addition of BG-NPs prepared by a sol-gel route to the CHT polymeric matrix improved the bioactivity of the nanocomposite scaffold, as seen by the precipitation of bone-like apatite layer upon immersion in simulated body fluid (SBF). Shape memory tests were carried out while the samples were immersed in varying compositions of water/ethanol mixtures. Dehydration with ethanol enables to fix a temporary shape of a deformed scaffold that recovers the initial geometry upon water uptake. The scaffolds present good shape memory properties characterized by a recovery ratio of 87.5% for CHT and 89.9% for CHT/BG-NPs and a fixity ratio of 97.2% for CHT and 98.2% for CHT/BG-NPs (for 30% compressive deformation). The applicability of such structures was demonstrated by a good geometrical accommodation of a previously compressed scaffold in a bone defect. The results indicate that the developed CHT/BG-NPs nanocomposite scaffolds have potential for being applied in bone tissue engineering. PMID:25843832

  10. Fabrication and Characterization of Three-Dimensional Macroscopic All-Carbon Scaffolds

    PubMed Central

    Lalwani, Gaurav; Kwaczala, Andrea Trinward; Kanakia, Shruti; Patel, Sunny C.; Judex, Stefan; Sitharaman, Balaji

    2012-01-01

    We report a simple method to fabricate macroscopic, 3-D, free standing, all-carbon scaffolds (porous structures) using multiwalled carbon nanotubes (MWCNTs) as the starting materials. The scaffolds prepared by radical initiated thermal crosslinking, and annealing of MWCNTs possess macroscale interconnected pores, robust structural integrity, stability, and conductivity. The porosity of the three-dimensional structure can be controlled by varying the amount of radical initiator, thereby allowing the design of porous scaffolds tailored towards specific potential applications. This method also allows the fabrication of 3-D scaffolds using other carbon nanomaterials such as single-walled carbon nanotubes, fullerenes, and graphene indicating that it could be used as a versatile method for 3-D assembly of carbon nanostructures with pi bond networks. PMID:23436939

  11. A design protocol for tailoring ice-templated scaffold structure

    PubMed Central

    Pawelec, K. M.; Husmann, A.; Best, S. M.; Cameron, R. E.

    2014-01-01

    In this paper, we show, for the first time, the key link between scaffold architecture and latent heat evolution during the production of porous biomedical collagen structures using freeze-drying. Collagen scaffolds are used widely in the biomedical industry for the repair and reconstruction of skeletal tissues and organs. Freeze-drying of collagen slurries is a standard industrial process, and, until now, the literature has sought to characterize the influence of set processing parameters including the freezing protocol and weight percentage of collagen. However, we are able to demonstrate, by monitoring the local thermal events within the slurry during solidification, that nucleation, growth and annealing processes can be controlled, and therefore we are able to control the resulting scaffold architecture. Based on our correlation of thermal profile measurements with scaffold architecture, we hypothesize that there is a link between the fundamental freezing of ice and the structure of scaffolds, which suggests that this concept is applicable not only for collagen but also for ceramics and pharmaceuticals. We present a design protocol of strategies for tailoring the ice-templated scaffold structure. PMID:24402916

  12. Heparinized collagen scaffolds with and without growth factors for the repair of diaphragmatic hernia

    PubMed Central

    Brouwer, Katrien M; Wijnen, René M; Reijnen, Daphne; Hafmans, Theo G; Daamen, Willeke F; van Kuppevelt, Toin H

    2013-01-01

    A regenerative medicine approach to restore the morphology and function of the diaphragm in congenital diaphragmatic hernia is especially challenging because of the position and flat nature of this organ, allowing cell ingrowth primarily from the perimeter. Use of porous collagen scaffolds for the closure of surgically created diaphragmatic defects in rats has been shown feasible, but better ingrowth of cells, specifically blood vessels and muscle cells, is warranted. To stimulate this process, heparin, a glycosaminoglycan involved in growth factor binding, was covalently bound to porous collagenous scaffolds (14%), with or without vascular endothelial growth factor (VEGF; 0.4 µg/mg scaffold), hepatocyte growth factor (HGF; 0.5 µg/mg scaffold) or a combination of VEGF + HGF (0.2 + 0.5 µg/mg scaffold). All components were located primarily at the outside of scaffolds. Scaffolds were implanted in the diaphragm of rats and evaluated after 2 and 12 weeks. No herniations or eventrations were observed, and in several cases, growth factor-substituted scaffolds showed macroscopically visible blood vessels at the lung site. The addition of heparin led to an accelerated ingrowth of blood vessels at 2 weeks. In all scaffold types, giant cells and immune cells were present primarily at the liver side of the scaffold, and immune cells and individual macrophages at the lung side; these cell types decreased in number from week 2 to week 12. The addition of growth factors did not influence cellular response to the scaffolds, indicating that further optimization with respect to dosage and release profile is needed. PMID:23867845

  13. Improved biocompatibility of novel poly(L-lactic acid)/?-tricalcium phosphate scaffolds prepared by an organic solvent-free method.

    PubMed

    Zhao, Xue-feng; Li, Xiao-dong; Kang, Yun-qing; Yuan, Quan

    2011-01-01

    A porous poly(L-lactic acid)/?-tricalcium phosphate (PLLA/?-TCP) composite scaffold was fabricated using a novel technique comprising powder mixing, compression molding, low-temperature treatment, and particulate leaching without any organic solvent. The effect of this scaffold on osteoblast proliferation and differentiation was evaluated in vitro. The fabricated scaffold had a homogeneously interconnected porous structure with a porosity of 70% and compressive strength of 1.35 MPa. The methylthiazol tetrazolium values and alkaline phosphatase (ALP) activity of osteoblasts seeded on the solvent-free scaffold were significant higher than those of the control. Using real-time PCR, gene expressions of ALP, osteocalcin, and type 1 collagen were shown to be upregulated. As the method does not use any organic solvent, it eliminates problems associated with organic solvent residue and therefore improves the cell compatibility. It has a promising potential for the preparation of porous scaffold for bone tissue engineering. PMID:21760732

  14. Towards the Development of Smart 3D "gated scaffolds" for on-command delivery.

    PubMed

    Mas, Núria; Arcos, Daniel; Polo, Lorena; Aznar, Elena; Sánchez-Salcedo, Sandra; Sancenón, Félix; García, Ana; Marcos, M Dolores; Baeza, Alejandro; Vallet-Regí, María; Martínez-Máñez, Ramón

    2014-12-10

    A new approach towards the design of "gated scaffolds" based on the combination of capped mesoporous silica nanoparticles (MSNs) with porous biomaterials is reported. Using this approach, a 3D gelatin-based scaffold able to selectively deliver cargo in the presence of an APase enzyme is prepared and tested. This new design opens up the possibility of developing new smart biomaterials with advanced drug-delivery features. PMID:25079146

  15. Formulation and characterization of silk sericin-PVA scaffold crosslinked with genipin.

    PubMed

    Aramwit, Pornanong; Siritientong, Tippawan; Kanokpanont, Sorada; Srichana, Teerapol

    2010-12-01

    A porous-three-dimensional scaffold shows several advantages in terms of tissue engineering since it can provide a framework for cells to attach, proliferate and form an extracellular matrix. Sericin, a by-product from the silk industry, can form a three-dimensional scaffold with PVA after freeze-drying but has a fragile structure. Glycerin (as a plasticizer) and genipin (a crosslinking agent) are necessary to make a strong and stable matrix. Our objective was to investigate the properties of a three-dimensional silk sericin and PVA scaffold with and without glycerin and genipin at various concentrations. SEM showed that adding glycerin into scaffold gave better uniformity and porosity. Smaller pore sizes and better uniformity were found as the concentration of genipin in the scaffold increased. The results of FTIR indicated that glycerin retained a high moisture content and had a major effect at 3286 cm(-1), indicating the presence of water molecule in the matrix structure. Adding genipin into the scaffold resulted in a higher degree of crosslinking or fewer free ?-amino groups, as shown by the decrease in the stretching (=C-H) peak and absorption peaks around 1370-1650 cm(-1), respectively. The sericin/PVA scaffold had a low water sorption capacity, but adding glycerin significantly increased this property. Genipin further enhanced the moisture absorption capacity of the scaffold and extended the time taken to reach equilibrium. After immersing the sericin/PVA scaffold into purified water, the scaffold completely dissolved within an hour, whereas the scaffolds containing glycerin or glycerin with 0.1% genipin swelled 8 and 11 times, respectively, compared with the initial stage after 6h of immersion. In terms of mechanical properties, the sericin/PVA/glycerin scaffold exhibited a similar compressive strength to the scaffold with a high genipin concentration, whereas a low concentration of genipin softened and reduced the compressive strength of the scaffold. A small amount of sericin was released from the scaffold and a higher concentration of genipin, resulting in less protein leaching compared to non-crosslinked sericin/PVA. The fraction of protein released from the sericin/PVA/glycerin scaffold was about 4%, with values of about 1 and 0.04% in the case of scaffolds with 0.01 and 0.1% genipin, respectively. All results indicated that the composition of the scaffolds had a significant effect on their physical properties, and that can easily be tuned to obtain scaffolds suitable for biological applications. PMID:20804781

  16. Evaluation of osteoconductive scaffolds in the canine femoral multi-defect model.

    PubMed

    Luangphakdy, Viviane; Walker, Esteban; Shinohara, Kentaro; Pan, Hui; Hefferan, Theresa; Bauer, Thomas W; Stockdale, Linda; Saini, Sunil; Dadsetan, Mahrokh; Runge, M Brett; Vasanji, Amit; Griffith, Linda; Yaszemski, Michael; Muschler, George F

    2013-03-01

    Treatment of large segmental bone defects remains an unsolved clinical challenge, despite a wide array of existing bone graft materials. This project was designed to rapidly assess and compare promising biodegradable osteoconductive scaffolds for use in the systematic development of new bone regeneration methodologies that combine scaffolds, sources of osteogenic cells, and bioactive scaffold modifications. Promising biomaterials and scaffold fabrication methods were identified in laboratories at Rutgers, MIT, Integra Life Sciences, and Mayo Clinic. Scaffolds were fabricated from various materials, including poly(L-lactide-co-glycolide) (PLGA), poly(L-lactide-co-?-caprolactone) (PLCL), tyrosine-derived polycarbonate (TyrPC), and poly(propylene fumarate) (PPF). Highly porous three-dimensional (3D) scaffolds were fabricated by 3D printing, laser stereolithography, or solvent casting followed by porogen leaching. The canine femoral multi-defect model was used to systematically compare scaffold performance and enable selection of the most promising substrate(s) on which to add cell sourcing options and bioactive surface modifications. Mineralized cancellous allograft (MCA) was used to provide a comparative reference to the current clinical standard for osteoconductive scaffolds. Percent bone volume within the defect was assessed 4 weeks after implantation using both MicroCT and limited histomorphometry. Bone formed at the periphery of all scaffolds with varying levels of radial ingrowth. MCA produced a rapid and advanced stage of bone formation and remodeling throughout the defect in 4 weeks, greatly exceeding the performance of all polymer scaffolds. Two scaffold constructs, TyrPC(PL)/TCP and PPF4(SLA)/HA(PLGA) (Dip), proved to be significantly better than alternative PLGA and PLCL scaffolds, justifying further development. MCA remains the current standard for osteoconductive scaffolds. PMID:23215980

  17. Evaluation of Osteoconductive Scaffolds in the Canine Femoral Multi-Defect Model

    PubMed Central

    Luangphakdy, Viviane; Walker, Esteban; Shinohara, Kentaro; Pan, Hui; Hefferan, Theresa; Bauer, Thomas W.; Stockdale, Linda; Saini, Sunil; Dadsetan, Mahrokh; Runge, M. Brett; Vasanji, Amit; Griffith, Linda; Yaszemski, Michael

    2013-01-01

    Treatment of large segmental bone defects remains an unsolved clinical challenge, despite a wide array of existing bone graft materials. This project was designed to rapidly assess and compare promising biodegradable osteoconductive scaffolds for use in the systematic development of new bone regeneration methodologies that combine scaffolds, sources of osteogenic cells, and bioactive scaffold modifications. Promising biomaterials and scaffold fabrication methods were identified in laboratories at Rutgers, MIT, Integra Life Sciences, and Mayo Clinic. Scaffolds were fabricated from various materials, including poly(L-lactide-co-glycolide) (PLGA), poly(L-lactide-co-?-caprolactone) (PLCL), tyrosine-derived polycarbonate (TyrPC), and poly(propylene fumarate) (PPF). Highly porous three-dimensional (3D) scaffolds were fabricated by 3D printing, laser stereolithography, or solvent casting followed by porogen leaching. The canine femoral multi-defect model was used to systematically compare scaffold performance and enable selection of the most promising substrate(s) on which to add cell sourcing options and bioactive surface modifications. Mineralized cancellous allograft (MCA) was used to provide a comparative reference to the current clinical standard for osteoconductive scaffolds. Percent bone volume within the defect was assessed 4 weeks after implantation using both MicroCT and limited histomorphometry. Bone formed at the periphery of all scaffolds with varying levels of radial ingrowth. MCA produced a rapid and advanced stage of bone formation and remodeling throughout the defect in 4 weeks, greatly exceeding the performance of all polymer scaffolds. Two scaffold constructs, TyrPCPL/TCP and PPF4SLA/HAPLGA Dip, proved to be significantly better than alternative PLGA and PLCL scaffolds, justifying further development. MCA remains the current standard for osteoconductive scaffolds. PMID:23215980

  18. Exact approaches for scaffolding

    PubMed Central

    2015-01-01

    This paper presents new structural and algorithmic results around the scaffolding problem, which occurs prominently in next generation sequencing. The problem can be formalized as an optimization problem on a special graph, the "scaffold graph". We prove that the problem is polynomial if this graph is a tree by providing a dynamic programming algorithm for this case. This algorithm serves as a basis to deduce an exact algorithm for general graphs using a tree decomposition of the input. We explore other structural parameters, proving a linear-size problem kernel with respect to the size of a feedback-edge set on a restricted version of Scaffolding. Finally, we examine some parameters of scaffold graphs, which are based on real-world genomes, revealing that the feedback edge set is significantly smaller than the input size. PMID:26451725

  19. Chemical Sintering Generates Uniform Porous Hyaluronic Acid Hydrogels

    PubMed Central

    Cam, Cynthia; Segura, Tatiana

    2014-01-01

    Implantation of scaffolds for tissue repair has been met with limited success primarily due to the inability to achieve vascularization within the construct. Many strategies have shifted to incorporate pores into these scaffolds to encourage rapid cellular infiltration and subsequent vascular ingrowth. We utilized an efficient chemical sintering technique to create a uniform network of polymethyl methacrylate (PMMA) microspheres for porous hyaluronic acid hydrogel formation. The porous hydrogels generated from chemical sintering possessed comparable pore uniformity and interconnectivity as the commonly used non- and heat sintering techniques. Moreover, similar cell response to the porous hydrogels generated from each sintering approach was observed in cell viability, spreading, proliferation in vitro, as well as, cellular invasion in vivo. We propose chemical sintering of PMMA microspheres using a dilute acetone solution as an alternative method to generating porous hyaluronic acid hydrogels since it requires equal or ten-fold less processing time as the currently used non-sintering or heat sintering technique, respectively. PMID:24120847

  20. Biomimetic gradient scaffold from ice-templating for self-seeding of cells with capillary effect.

    PubMed

    Bai, Hao; Wang, Dong; Delattre, Benjamin; Gao, Weiwei; De Coninck, Joël; Li, Song; Tomsia, Antoni P

    2015-07-01

    One of the most important issues in bone tissue engineering is the search for new materials and processing techniques to create novel scaffolds with 3-D porous structures. Although many properties such as biodegradability and porosity have been considered in designing bone scaffolds, very limited attention is paid to their capillary effect. In nature, capillary effect is ubiquitously used by plants and animals to constantly transport water and nutrients based on morphological and/or chemical gradient structures at multiple length-scales. In this work, we developed a modified freeze-casting technique to prepare ceramic scaffolds with gradient channel structures. The results show that our hydroxyapatite (HA) scaffolds have interconnected gradient channels that mimic the porous network of natural bone. More importantly, we demonstrate that such a scaffold has a very unique capillary behavior that promotes the self-seeding of cells when in contact with a cell solution due to spontaneous capillary flow generated from gradient channel structures. The strategy developed here provides a new avenue for designing "smart" scaffolds with complex porous structures and biological functions that mimic natural tissues. PMID:25871536

  1. Scaffolds in Tendon Tissue Engineering

    PubMed Central

    Longo, Umile Giuseppe; Lamberti, Alfredo; Petrillo, Stefano; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair. PMID:22190961

  2. Engineering Pre-vascularized Scaffolds for Bone Regeneration.

    PubMed

    Barabaschi, Giada D G; Manoharan, Vijayan; Li, Qing; Bertassoni, Luiz E

    2015-01-01

    Survival of functional tissue constructs of clinically relevant size depends on the formation of an organized and uniformly distributed network of blood vessels and capillaries. The lack of such vasculature leads to spatio-temporal gradients in oxygen, nutrients and accumulation of waste products inside engineered tissue constructs resulting in negative biological events at the core of the scaffold. Unavailability of a well-defined vasculature also results in ineffective integration of scaffolds to the host vasculature upon implantation. Arguably, one of the greatest challenges in engineering clinically relevant bone substitutes, therefore, has been the development of vascularized bone scaffolds. Various approaches ranging from peptide and growth factor functionalized biomaterials to hyper-porous scaffolds have been proposed to address this problem with reasonable success. An emerging alternative to address this challenge has been the fabrication of pre-vascularized scaffolds by taking advantage of biomanufacturing techniques, such as soft- and photo-lithography or 3D bioprinting, and cell-based approaches, where functional capillaries are engineered in cell-laden scaffolds prior to implantation. These strategies seek to engineer pre-vascularized tissues in vitro, allowing for improved anastomosis with the host vasculature upon implantation, while also improving cell viability and tissue development in vitro. This book chapter provides an overview of recent methods to engineer pre-vascularized scaffolds for bone regeneration. We first review the development of functional blood capillaries in bony structures and discuss controlled delivery of growth factors, co-culture systems, and on-chip studies to engineer vascularized cell-laden biomaterials. Lastly, we review recent studies using microfabrication techniques and 3D printing to engineer pre-vascularized scaffolds for bone tissue engineering. PMID:26545745

  3. Honeycomb-structured films by multifunctional amphiphilic biodegradable copolymers: surface morphology control and biomedical application as scaffolds for cell growth.

    PubMed

    Zhu, Yingdan; Sheng, Ruilong; Luo, Ting; Li, Hui; Sun, Jingjing; Chen, Shengdian; Sun, Wenyan; Cao, Amin

    2011-07-01

    Recently, fabrication of functional porous polymer films with patterned surface structures at the scale from nanometer to micrometer has been attracting increasing interests in material science and nanobiotechnology. In this work, we present new preparation of two series of multifunctional amphiphilic copolymers and preparation of their microporous thin films on solid substrates. First, diblock dendritic poly(l-lysine)-b-poly(l-lactide)s and triblock dendritic poly(l-lysine)-b-poly(l-lactide)-b-dendritic poly(l-lysine)s (C1-C6) were synthesized through 4-dimethylaminopyridine (DMAP)-catalyzed living ring-opening polymerization of (l-)-lactide with (l-)-lysine dendron initiators, and their structures were characterized by nuclear magnetic resonance spectrometer (NMR), gel permeation chromatography (GPC) and matrix-assisted laser desorption/ionization Fourier-transformed mass spectra (MALDI-FTMS). Employing the breath-figure (BF) fabrication strategy, thin films of the synthesized amphiphiles (C1-C6) were drop-cast, and their surface topologies were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the effects of new amphiphile structure and drop-casting parameters of amphiphile concentration, humidity and temperature on self-assembly of ordered porous surface were studied. Furthermore, the influence of surface energy of drop-casting substrates was additionally investigated. With a human cervical epithelial carcinoma cell line (HeLa), cytotoxicity of the prepared honeycomb-structured films by new amphiphile C6 was evaluated by thiazoyl-blue-tetrazolium-bromide (MTT) assay, and HeLa cell growth behavior with microporous amphiphile films as the scaffolds was also examined. It was found that tunable micropore diameter sizes and well ordered surface topologies of BF films could be achieved for the new prepared amphiphiles, and utilization of the honeycomb-like microporous films as scaffolds indicated favorable enhancement in cell proliferation. Therefore, the honeycomb-structured films by these biocompatible multifunctional amphiphiles may provide new materials as 3D-scaffold materials for potential application in tissue engineering and regeneration. PMID:21699231

  4. Synthesis, Characterization, and Biological Evaluation of Gelatin-based Scaffolds

    E-print Network

    Tronci, G

    2011-01-01

    This thesis presents the development of entropy-elastic gelatin based networks in the form of films or scaffolds. The materials have good prospects for biomedical applications, especially in the context of bone regeneration. Entropy-elastic gelatin based hydrogel films with varying crosslinking densities were prepared with tailored mechanical properties. Gelatin was covalently crosslinked in water above its sol gel transition, which suppressed the gelatin chain helicity. Amorphous films were prepared with tailorable degrees of swelling and wet state Young's modulus. The knowledge gained with this bulk material was transferred to the integrated process of foaming and crosslinking to obtain porous gelatin-based scaffolds. A gelatin solution was foamed in the presence of saponin and the resulting foam was fixed by chemical crosslinking with a diisocyanate. The scaffolds were analyzed in the dry state by micro computed tomography (\\mu CT, porosity: 65\\pm 11-73\\pm 14 vol.-%), and scanning electron microscopy (SEM,...

  5. Biocompatible Collagen Paramagnetic Scaffold for Controlled Drug Release.

    PubMed

    Bettini, Simona; Bonfrate, Valentina; Syrgiannis, Zois; Sannino, Alessandro; Salvatore, Luca; Madaghiele, Marta; Valli, Ludovico; Giancane, Gabriele

    2015-09-14

    A porous collagen-based hydrogel scaffold was prepared in the presence of iron oxide nanoparticles (NPs) and was characterized by means of infrared spectroscopy and scanning electron microscopy. The hybrid scaffold was then loaded with fluorescein sodium salt as a model compound. The release of the hydrosoluble species was triggered and accurately controlled by the application of an external magnetic field, as monitored by fluorescence spectroscopy. The biocompatibility of the proposed matrix was also tested by the MTT assay performed on 3T3 cells. Cell viability was only slightly reduced when the cells were incubated in the presence of the collagen-NP hydrogel, compared to controls. The economicity of the chemical protocol used to obtain the paramagnetic scaffolds as well as their biocompatibility and the safety of the external trigger needed to induce the drug release suggest the proposed collagen paramagnetic matrices for a number of applications including tissue engeneering and drug delivery. PMID:26270197

  6. Design and fabrication of biomimetic multiphased scaffolds for ligament-to-bone fixation.

    PubMed

    He, Jiankang; Zhang, Wenyou; Liu, Yaxiong; Li, Xiang; Li, Dichen; Jin, Zhongmin

    2015-05-01

    Conventional ligament grafts with single material composition cannot effectively integrate with the host bones due to mismatched properties and eventually affect their long-term function in vivo. Here we presented a multi-material strategy to design and fabricate composite scaffolds including ligament, interface and bone multiphased regions. The interface region consists of triphasic layers with varying material composition and porous structure to mimic native ligament-to-bone interface while the bone region contains polycaprolactone (PCL) anchor and microchanneled ceramic scaffolds to potentially provide combined mechanical and biological implant-bone fixation. Finite element analysis (FEA) demonstrated that the multiphased scaffolds with interference value smaller than 0.5 mm could avoid the fracture of ceramic scaffold during the implantation process, which was validated by in-vitro implanting the multiphased scaffolds into porcine joint bones. Pull-out experiment showed that the initial fixation between the multiphased scaffolds with 0.47 mm interference and the host bones could withstand the maximum force of 360.31±97.51 N, which can be improved by reinforcing the ceramic scaffolds with biopolymers. It is envisioned that the multiphased scaffold could potentially induce the regeneration of a new bone as well as interfacial tissue with the gradual degradation of the scaffold and subsequently realize long-term biological fixation of the implant with the host bone. PMID:25746239

  7. Biotemplated syntheses of macroporous materials for bone tissue engineering scaffolds and experiments in vitro and vivo.

    PubMed

    Li, Xing; Zhao, Yayun; Bing, Yue; Li, Yaping; Gan, Ning; Guo, Zhiyong; Peng, Zhaoxiang; Zhu, Yabin

    2013-06-26

    The macroporous materials were prepared from the transformation of cuttlebone as biotemplates under hydrothermal reactions and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric/differential thermal analyses (TG-DTA), and scanning electron microscopy (SEM). Cell experimental results showed that the prepared materials as bone tissue engineering scaffolds or fillers had fine biocompatibility suitable for adhesion and proliferation of the hMSCs (human marrow mesenchymal stem cells). Histological analyses were carried out by implanting the scaffolds into a rabbit femur, where the bioresorption, degradation, and biological activity of the scaffolds were observed in the animal body. The prepared scaffolds kept the original three-dimensional frameworks with the ordered porous structures, which made for blood circulation, nutrition supply, and the cells implantation. The biotemplated syntheses could provide a new effective approach to prepare the bone tissue engineering scaffold materials. PMID:23742223

  8. Impact of silk fibroin-based scaffold structures on human osteoblast MG63 cell attachment and proliferation.

    PubMed

    Varkey, Aneesia; Venugopal, Elakkiya; Sugumaran, Ponjanani; Janarthanan, Gopinathan; Pillai, Mamatha M; Rajendran, Selvakumar; Bhattacharyya, Amitava

    2015-01-01

    The present study was carried out to investigate the impact of various types of silk fibroin (SF) scaffolds on human osteoblast-like cell (MG63) attachment and proliferation. SF was isolated from Bombyx mori silk worm cocoons after degumming. Protein concentration in the degummed SF solution was estimated using Bradford method. Aqueous SF solution was used to fabricate three different types of scaffolds, viz, electrospun nanofiber mat, sponge, and porous film. The structures of the prepared scaffolds were characterized using optical microscopy and field emission scanning electron microscopy. The changes in the secondary structure of the proteins and the thermal behavior of the scaffolds were determined by Fourier transform infrared spectroscopy and thermo-gravimetric analysis, respectively. The biodegradation rate of scaffolds was determined by incubating the scaffolds in simulated body fluid for 4 weeks. MG63 cells were seeded on the scaffolds and their attachment and proliferation onto the scaffolds were studied. The MTT assay was carried out to deduce the toxicity of the developed scaffolds. All the scaffolds were found to be biocompatible. The amount of collagen produced by the osteoblast-like cells growing on different scaffolds was estimated. PMID:26491306

  9. Impact of silk fibroin-based scaffold structures on human osteoblast MG63 cell attachment and proliferation

    PubMed Central

    Varkey, Aneesia; Venugopal, Elakkiya; Sugumaran, Ponjanani; Janarthanan, Gopinathan; Pillai, Mamatha M; Rajendran, Selvakumar; Bhattacharyya, Amitava

    2015-01-01

    The present study was carried out to investigate the impact of various types of silk fibroin (SF) scaffolds on human osteoblast-like cell (MG63) attachment and proliferation. SF was isolated from Bombyx mori silk worm cocoons after degumming. Protein concentration in the degummed SF solution was estimated using Bradford method. Aqueous SF solution was used to fabricate three different types of scaffolds, viz, electrospun nanofiber mat, sponge, and porous film. The structures of the prepared scaffolds were characterized using optical microscopy and field emission scanning electron microscopy. The changes in the secondary structure of the proteins and the thermal behavior of the scaffolds were determined by Fourier transform infrared spectroscopy and thermo-gravimetric analysis, respectively. The biodegradation rate of scaffolds was determined by incubating the scaffolds in simulated body fluid for 4 weeks. MG63 cells were seeded on the scaffolds and their attachment and proliferation onto the scaffolds were studied. The MTT assay was carried out to deduce the toxicity of the developed scaffolds. All the scaffolds were found to be biocompatible. The amount of collagen produced by the osteoblast-like cells growing on different scaffolds was estimated. PMID:26491306

  10. Biofabrication of a PLGA-TCP-based porous bioactive bone substitute with sustained release of icaritin.

    PubMed

    Xie, Xin-Hui; Wang, Xin-Luan; Zhang, Ge; He, Yi-Xin; Leng, Yang; Tang, Ting-Ting; Pan, Xiaohua; Qin, Ling

    2015-08-01

    A phytomolecule, icaritin, has been identified and shown to be osteopromotive for the prevention of osteoporosis and osteonecrosis. This study aimed to produce a bioactive poly (l-lactide-co-glycolide)-tricalcium phosphate (PLGA-TCP)-based porous scaffold incorporating the osteopromotive phytomolecule icaritin, using a fine spinning technology. Both the structure and the composition of icaritin-releasing PLGA-TCP-based scaffolds were evaluated by scanning electron microscopy (SEM). The porosity was quantified by both water absorption and micro-computed tomography (micro-CT). The mechanical properties were evaluated using a compression test. In vitro release of icaritin from the PLGA-TCP scaffold was quantified by high-performance liquid chromatography (HPLC). The attachment, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the composite scaffold were evaluated. Both an in vitro cytotoxicity test and an in vivo test via muscular implantation were conducted to confirm the scaffold's biocompatibility. The results showed that the PLGA-TCP-icaritin composite scaffold was porous, with interconnected macro- (about 480?µm) and micropores (2-15?µm). The mechanical properties of the PLGA-TCP-icaritin scaffold were comparable with those of the pure PLGA-TCP scaffold, yet was spinning direction-dependent. Icaritin content was detected in the medium and increased with time. The PLGA-TCP-icaritin scaffold facilitated the attachment, proliferation and osteogenic differentiation of BMSCs. In vitro cytotoxicity test and in vivo intramuscular implantation showed that the composite scaffold had no toxicity with good biocompatibility. In conclusion, an osteopromotive phytomolecule, icaritin, was successfully incorporated into PLGA-TCP to form an innovative porous composite scaffold with sustained release of osteopromotive icaritin, and this scaffold had good biocompatibility and osteopromotion, suggesting its potential for orthopaedic applications. PMID:23255530

  11. Bioceramics and Scaffolds: A Winning Combination for Tissue Engineering

    PubMed Central

    Baino, Francesco; Novajra, Giorgia; Vitale-Brovarone, Chiara

    2015-01-01

    In the last few decades, we have assisted to a general increase of elder population worldwide associated with age-related pathologies. Therefore, there is the need for new biomaterials that can substitute damaged tissues, stimulate the body’s own regenerative mechanisms, and promote tissue healing. Porous templates referred to as “scaffolds” are thought to be required for three-dimensional tissue growth. Bioceramics, a special set of fully, partially, or non-crystalline ceramics (e.g., calcium phosphates, bioactive glasses, and glass–ceramics) that are designed for the repair and reconstruction of diseased parts of the body, have high potential as scaffold materials. Traditionally, bioceramics have been used to fill and restore bone and dental defects (repair of hard tissues). More recently, this category of biomaterials has also revealed promising applications in the field of soft-tissue engineering. Starting with an overview of the fundamental requirements for tissue engineering scaffolds, this article provides a detailed picture on recent developments of porous bioceramics and composites, including a summary of common fabrication technologies and a critical analysis of structure–property and structure–function relationships. Areas of future research are highlighted at the end of this review, with special attention to the development of multifunctional scaffolds exploiting therapeutic ion/drug release and emerging applications beyond hard tissue repair.

  12. Cardiomyocyte behavior on biodegradable polyurethane/gold nanocomposite scaffolds under electrical stimulation.

    PubMed

    Ganji, Yasaman; Li, Qian; Quabius, Elgar Susanne; Böttner, Martina; Selhuber-Unkel, Christine; Kasra, Mehran

    2016-02-01

    Following a myocardial infarction (MI), cardiomyocytes are replaced by scar tissue, which decreases ventricular contractile function. Tissue engineering is a promising approach to regenerate such damaged cardiomyocyte tissue. Engineered cardiac patches can be fabricated by seeding a high density of cardiac cells onto a synthetic or natural porous polymer. In this study, nanocomposite scaffolds made of gold nanotubes/nanowires incorporated into biodegradable castor oil-based polyurethane were employed to make micro-porous scaffolds. H9C2 cardiomyocyte cells were cultured on the scaffolds for one day, and electrical stimulation was applied to improve cell communication and interaction in neighboring pores. Cells on scaffolds were examined by fluorescence microscopy and scanning electron microscopy, revealing that the combination of scaffold design and electrical stimulation significantly increased cell confluency of H9C2 cells on the scaffolds. Furthermore, we showed that the gene expression levels of Nkx2.5, atrial natriuretic peptide (ANF) and natriuretic peptide precursor B (NPPB), which are functional genes of the myocardium, were up-regulated by the incorporation of gold nanotubes/nanowires into the polyurethane scaffolds, in particular after electrical stimulation. PMID:26652343

  13. Nano-composite scaffolds for bone tissue engineering containing silver nanoparticles: preparation, characterization and biological properties.

    PubMed

    Marsich, Eleonora; Bellomo, Francesca; Turco, Gianluca; Travan, Andrea; Donati, Ivan; Paoletti, Sergio

    2013-07-01

    In this study nano-composite scaffolds to be used as bone grafts have been endowed with antibacterial properties owing to the presence of silver nanoparticles. The alginate/hydroxyapatite composite scaffolds were prepared by internal gelation followed by a freeze-drying procedure to obtain a porous structure. The nanoparticles were prepared in presence of a lactose modified-chitosan and this colloidal solution was adsorbed on the scaffolds by exploiting electrostatic interactions. The adsorption and release of the silver from the composite scaffold was measured by ICP-AES and spectrofluorimetry measurements. Micro-computed tomography analysis of the scaffolds showed a homogeneous porous structure with average pore sizes of 341.5 ?m and porosity of 80 %. In vitro biological tests (MTS and killing kinetics assays) demonstrated that silver does not affect the ability of the scaffolds to promote osteoblasts proliferation and that at the same time it exerts a strong bactericidal effect against both Gram+ and Gram- bacterial strains. Overall, the combined results indicate that these biocompatible antimicrobial scaffolds possess ideal characteristics for tissue engineering applications. PMID:23553569

  14. The effects of different crossing-linking conditions of genipin on type I collagen scaffolds: an in vitro evaluation.

    PubMed

    Zhang, Xiujie; Chen, Xueying; Yang, Ting; Zhang, Naili; Dong, Li; Ma, Shaoying; Liu, Xiaoming; Zhou, Mo; Li, Baoxing

    2014-12-01

    The purpose of this paper is to analyze the properties of fabricating rat tail type I collagen scaffolds cross-linked with genipin under different conditions. The porous genipin cross-linked scaffolds are obtained through a two step freeze-drying process. To find out the optimal cross-link condition, we used different genipin concentrations and various cross-linked temperatures to prepare the scaffolds in this study. The morphologies of the scaffolds were characterized by scanning electron microscope, and the mechanical properties of the scaffolds were evaluated under dynamic compression. Additionally, the cross-linking degree was assessed by ninhydrin assay. To investigate the swelling ratio and the in vitro degradation of the collagen scaffold, the tests were also carried out by immersion of the scaffolds in a PBS solution or digestion in a type I collagenase respectively. The morphologies of the non-cross-linked scaffolds presented a lattice-like structure while the cross-linked ones displayed a sheet-like framework. The morphology of the genipin cross-linked scaffolds could be significantly changed by either increasing genipin concentration or the temperature. The swelling ratio of each cross-linked scaffold was much lower than that of the control (non-cross-linked).The ninhydrin assay demonstrated that the higher temperature and genipin concentration could obviously increase the cross-linking efficiency. The in vitro degradation studies indicated that genipin cross-linking can effectively elevate the biostability of the scaffolds. The biocompatibility and cytotoxicity of the scaffolds was evaluated by culturing rat chondrocytes on the scaffold in vitro and by MTT. The results of MTT and the fact that the chondrocytes adhered well to the scaffolds demonstrated that genipin cross-linked scaffolds possessed an excellent biocompatibility and low cytotoxicity. Based on these results, 0.3 % genipin concentrations and 37 °C cross-linked temperatures are recommended. PMID:24442821

  15. The interplay between tissue growth and scaffold degradation in engineered tissue constructs.

    PubMed

    O'Dea, R D; Osborne, J M; El Haj, A J; Byrne, H M; Waters, S L

    2013-11-01

    In vitro tissue engineering is emerging as a potential tool to meet the high demand for replacement tissue, caused by the increased incidence of tissue degeneration and damage. A key challenge in this field is ensuring that the mechanical properties of the engineered tissue are appropriate for the in vivo environment. Achieving this goal will require detailed understanding of the interplay between cell proliferation, extracellular matrix (ECM) deposition and scaffold degradation. In this paper, we use a mathematical model (based upon a multiphase continuum framework) to investigate the interplay between tissue growth and scaffold degradation during tissue construct evolution in vitro. Our model accommodates a cell population and culture medium, modelled as viscous fluids, together with a porous scaffold and ECM deposited by the cells, represented as rigid porous materials. We focus on tissue growth within a perfusion bioreactor system, and investigate how the predicted tissue composition is altered under the influence of (1) differential interactions between cells and the supporting scaffold and their associated ECM, (2) scaffold degradation, and (3) mechanotransduction-regulated cell proliferation and ECM deposition. Numerical simulation of the model equations reveals that scaffold heterogeneity typical of that obtained from [Formula: see text]CT scans of tissue engineering scaffolds can lead to significant variation in the flow-induced mechanical stimuli experienced by cells seeded in the scaffold. This leads to strong heterogeneity in the deposition of ECM. Furthermore, preferential adherence of cells to the ECM in favour of the artificial scaffold appears to have no significant influence on the eventual construct composition; adherence of cells to these supporting structures does, however, lead to cell and ECM distributions which mimic and exaggerate the heterogeneity of the underlying scaffold. Such phenomena have important ramifications for the mechanical integrity of engineered tissue constructs and their suitability for implantation in vivo. PMID:22986893

  16. bFGF-containing electrospun gelatin scaffolds with controlled nano-architectural features for directed angiogenesis

    PubMed Central

    Montero, Ramon B.; Vial, Ximena; Nguyen, Dat Tat; Farhand, Sepehr; Reardon, Mark; Pham, Si M.; Tsechpenakis, Gavriil; Andreopoulos, Fotios M.

    2011-01-01

    Current therapeutic angiogenesis strategies are focused on the development of biologically responsive scaffolds that can deliver multiple angiogenic cytokines and/or cells in ischemic regions. Herein, we report on a novel electrospinning approach to fabricate cytokine-containing nanofibrous scaffolds with tunable architecture to promote angiogenesis. Fiber diameter and uniformity were controlled by varying the concentration of the polymeric (i.e. gelatin) solution, the feed rate, needle to collector distance, and electric field potential between the collector plate and injection needle. Scaffold fiber orientation (random vs. aligned) was achieved by alternating the polarity of two parallel electrodes placed on the collector plate thus dictating fiber deposition patterns. Basic fibroblast growth factor (bFGF) was physically immobilized within the gelatin scaffolds at variable concentrations and human umbilical vein endothelial cells (HUVEC) were seeded on the top of the scaffolds. Cell proliferation and migration was assessed as a function of growth factor loading and scaffold architecture. HUVECs successfully adhered onto gelatin B scaffolds and cell proliferation was directly proportional to the loading concentrations of the growth factor (0–100 bFGF ng/mL). Fiber orientation had a pronounced effect on cell morphology and orientation. Cells were spread along the fibers of the electrospun scaffolds with the aligned orientation and developed a spindle-like morphology parallel to the scaffold's fibers. In contrast, cells seeded onto the scaffolds with random fiber orientation, did not demonstrate any directionality and appeared to have a rounder shape. Capillary formation (i.e. sprouts length and number of sprouts per bead), assessed in a 3-D in vitro angiogenesis assay, was a function of bFGF loading concentration (0 ng, 50 ng and 100 ng per scaffold) for both types of electrospun scaffolds (i.e. with aligned or random fiber orientation). PMID:22200610

  17. Microfluidic Generation of Porous Microcarriers for Three-Dimensional Cell Culture.

    PubMed

    Wang, Jie; Cheng, Yao; Yu, Yunru; Fu, Fanfan; Chen, Zhuoyue; Zhao, Yuanjin; Gu, Zhongze

    2015-12-16

    Inspired by the microstructure of the stem cell niche, which is generally composed of adjacent cell protection layers and an extracellular matrix (ECM), we present novel microfluidic porous microcarriers for cell culture that consist of external-internal connected scaffold structures and biopolymer matrix fillers. The biomimetic scaffold structure of the porous microcarriers not only avoids the imposition of shear forces on the encapsulated cells but also provides a confined microenvironment for cell self-assembly, whereas the biopolymers in the porous cores of the microcarriers can act as an ECM microenvironment to promote the formation of multicellular spheroid aggregates for biomedical applications. PMID:26634625

  18. Enhancing the bioactivity of Poly(lactic-co-glycolic acid) scaffold with a nano-hydroxyapatite coating for the treatment of segmental bone defect in a rabbit model

    PubMed Central

    Wang, De-Xin; He, Yao; Bi, Long; Qu, Ze-Hua; Zou, Ji-Wei; Pan, Zhen; Fan, Jun-Jun; Chen, Liang; Dong, Xin; Liu, Xiang-Nan; Pei, Guo-Xian; Ding, Jian-Dong

    2013-01-01

    Purpose Poly(lactic-co-glycolic acid) (PLGA) is excellent as a scaffolding matrix due to feasibility of processing and tunable biodegradability, yet the virgin scaffolds lack osteoconduction and osteoinduction. In this study, nano-hydroxyapatite (nHA) was coated on the interior surfaces of PLGA scaffolds in order to facilitate in vivo bone defect restoration using biomimetic ceramics while keeping the polyester skeleton of the scaffolds. Methods PLGA porous scaffolds were prepared and surface modification was carried out by incubation in modified simulated body fluids. The nHA coated PLGA scaffolds were compared to the virgin PLGA scaffolds both in vitro and in vivo. Viability and proliferation rate of bone marrow stromal cells of rabbits were examined. The constructs of scaffolds and autogenous bone marrow stromal cells were implanted into the segmental bone defect in the rabbit model, and the bone regeneration effects were observed. Results In contrast to the relative smooth pore surface of the virgin PLGA scaffold, a biomimetic hierarchical nanostructure was found on the surface of the interior pores of the nHA coated PLGA scaffolds by scanning electron microscopy. Both the viability and proliferation rate of the cells seeded in nHA coated PLGA scaffolds were higher than those in PLGA scaffolds. For bone defect repairing, the radius defects had, after 12 weeks implantation of nHA coated PLGA scaffolds, completely recuperated with significantly better bone formation than in the group of virgin PLGA scaffolds, as shown by X-ray, Micro-computerized tomography and histological examinations. Conclusion nHA coating on the interior pore surfaces can significantly improve the bioactivity of PLGA porous scaffolds. PMID:23690683

  19. 3D printed tricalcium phosphate scaffolds: Effect of SrO and MgO doping on in vivo osteogenesis in a rat distal femoral defect model.

    PubMed

    Tarafder, Solaiman; Davies, Neal M; Bandyopadhyay, Amit; Bose, Susmita

    2013-12-01

    The presence of interconnected macro pores is important in tissue engineering scaffolds for guided tissue regeneration. This study reports in vivo biological performance of interconnected macro porous tricalcium phosphate (TCP) scaffolds due to the addition of SrO and MgO as dopants in TCP. We have used direct three dimensional printing (3DP) technology for scaffold fabrication followed by microwave sintering. Mechanical strength was evaluated by scaffolds with 500 µm, 750 µm, and 1000 µm interconnected designed pore sizes. Maximum compressive strength of 12.01 ± 1.56 MPa was achieved for 500 µm interconnected designed pore size Sr-Mg doped scaffold. In vivo biological performance of the microwave sintered pure TCP and Sr-Mg doped TCP scaffolds was assessed by implanting 350 µm designed interconnected macro porous scaffolds in rat distal femoral defect. Sintered pore size of these 3D printed scaffolds were 311 ± 5.9 µm and 245 ± 7.5 µm for pure and SrO-MgO doped TCP scaffolds, respectively. These 3D printed scaffolds possessed multiscale porosity, i.e., 3D interconnected designed macro pores along with intrinsic micro pores. Histomorphology and histomorphometric analysis revealed a significant increase in osteoid like new bone formation, and accelerated mineralization inside SrO and MgO doped 3D printed TCP scaffolds as compared to pure TCP scaffolds. An increase in osteocalcin and type I collagen level was also observed in rat blood serum with SrO and MgO doped TCP scaffolds compared to pure TCP scaffolds. Our results show that these 3D printed SrO and MgO doped TCP scaffolds with multiscale porosity contributed to early healing through accelerated osteogenesis. PMID:24729867

  20. Fabrication of porous beta-tricalcium phosphate with microchannel and customized geometry based on gel-casting and rapid prototyping.

    PubMed

    Li, X; Bian, W; Li, D; Lian, Q; Jin, Z

    2011-03-01

    The tissue engineering scaffolds with three-dimensional porous structure are regarded to be beneficial to facilitate a sufficient supply of nutrients and enable cell ingrowth in bone reconstruction. However, the pores in scaffolds tend to be blocked by the cell ingrowth and result in a restraint of nutrient supply in the further side of the scaffold. An indirect approach of combining the rapid prototyping and gel-casting technique is introduced in this study to fabricate beta-tricalcium phosphate (beta-TCP) scaffolds which not only have interconnected porous structure, but also have a microchannel network inside. The scaffold was designed with customized geometry that matches the defect area, and a double-scale (micropores-microchannel) porous structure inside that is beneficial for cell ingrowth. The scaffolds fabricated have an open, uniform, and interconnected porous architecture with a pore size of 200-400 microm, and posses an internal channel network with a diameter of 600 microm. The porosity was controllable. The compressive yield strength was 4.5 MPa with a porosity of 70 per cent. X-ray diffraction analysis shows that these fabrication processes do not change the crystal structure and chemical composition of beta-TCP. With this technique, it was also possible to fabricate porous scaffolds with desired pore size, porosity, and microchannel, as well as customized geometries by other bioceramics. PMID:21485332

  1. Low temperature fabrication of high strength porous calcium phosphate and the evaluation of the osteoconductivity.

    PubMed

    Yu, Xianzhu; Cai, Shu; Xu, Guohua; Zhou, Wei; Wang, Dongmei

    2009-10-01

    Porous NaO(2)-MgO-CaO-P(2)O(5) bioglass doped beta-tri-calcium phosphate (beta-TCP) bioceramic possessing high mechanical properties and well pore structure with high porosity and high pore connectivity has been prepared through dipping method with the porous polyurethane as the pore forming template. The sintering mechanism and the mechanical properties of the bioglass doped beta-TCP scaffold have been investigated by the X-ray diffraction (XRD) analysis, Scanning electron microscope (SEM) and thermal differential analysis (DTA). The scaffold's in vivo osteoconductivity has been evaluated by implantation of scaffolds into the femurs of New Zealand rabbits. The results show that the porous structure can achieve the densification process at a low temperature about 950 degrees C by a solid solution sintering mechanism and hence dense macropore scaffold with a compressive strength of 4.32 MPa when the porosity is 75% has been obtained. The in vivo test shows that the Na(2)O-MgO-CaO-P(2)O(5) bioglass doped porous beta-TCP bioceramic has a relatively fast bone formation after implantation; after 1 month implantation new deposited bone tissue has been detected on the strut of the porous scaffold and degraded particles also has been found on the surface of the new formed bone. After 6 months implantation the porous scaffold has been thoroughly covered with new formed bone. Results show that the Na(2)O-MgO-CaO-P(2)O(5) bioglass doped porous beta-TCP bioceramic is potential bone tissue engineering scaffold for orthopedic use. PMID:19424778

  2. Dermal fibroblast infiltration of poly(?-caprolactone) scaffolds fabricated by melt electrospinning in a direct writing mode.

    PubMed

    Farrugia, Brooke L; Brown, Toby D; Upton, Zee; Hutmacher, Dietmar W; Dalton, Paul D; Dargaville, Tim R

    2013-06-01

    Melt electrospinning in a direct writing mode is a recent additive manufacturing approach to fabricate porous scaffolds for tissue engineering applications. In this study, we describe porous and cell-invasive poly (?-caprolactone) scaffolds fabricated by combining melt electrospinning and a programmable x-y stage. Fibers were 7.5 ± 1.6 µm in diameter and separated by interfiber distances ranging from 8 to 133 µm, with an average of 46 ± 22 µm. Micro-computed tomography revealed that the resulting scaffolds had a highly porous (87%), three-dimensional structure. Due to the high porosity and interconnectivity of the scaffolds, a top-seeding method was adequate to achieve fibroblast penetration, with cells present throughout and underneath the scaffold. This was confirmed histologically, whereby a 3D fibroblast-scaffold construct with full cellular penetration was produced after 14 days in vitro. Immunohistochemistry was used to confirm the presence and even distribution of the key dermal extracellular matrix proteins, collagen type I and fibronectin. These results show that melt electrospinning in a direct writing mode can produce cell invasive scaffolds, using simple top-seeding approaches. PMID:23443534

  3. A simultaneous process of 3D magnesium phosphate scaffold fabrication and bioactive substance loading for hard tissue regeneration.

    PubMed

    Lee, Jongman; Farag, Mohammad Mahmoud; Park, Eui Kyun; Lim, Jiwon; Yun, Hui-Suk

    2014-03-01

    A novel room temperature process was developed to produce a 3D porous magnesium phosphate (MgP) scaffold with high drug load/release efficiency for use in hard tissue regeneration through a combination of a paste extruding deposition (PED) system and cement chemistry. MgP scaffolds were prepared using a two-step process. The first step was fabrication of the 3D porous scaffold green body to control both the morphology and pore structure using a PED system without hardening. The second step was cementation, which was carried out by immersing the scaffold green body in the binder solution for hardening instead of the typical sintering process in ceramic scaffold fabrication. Separation of the manufacturing process and cement reaction was important to secure enough time to fabricate a 3D scaffold with various sizes and architectures under homogeneous extruding conditions. Because the whole process is carried out at room temperature, the bioactive molecules, which are easily denatured by heat, may apply to scaffolds during the process. Lysozyme was selected as a model bioactive substance to demonstrate the efficiency of this process; this was directly mixed into MgP powder to introduce homogeneous distribution in the scaffold. The extruding paste for the PED system was prepared using the MgP-lysozyme blended powder as starting materials. That is, both 3D scaffold fabrication and functionalization of the scaffold with bioactive substances could be carried out simultaneously. This process significantly enhanced both drug loading efficiency and release performance compared to the typical sintering process, where the drug is generally loaded by adsorption after heat treatment. The MgP scaffold developed in this study satisfied the required conditions for scaffolding in hard tissue regeneration in an ideal manner, including 3 dimensionally well-interconnected pore structures, favorable mechanical properties, biodegradability, good cell affinity and in vitro biocompatibility; thus, it has excellent potential for application in the field of biomaterials. PMID:24433911

  4. Fabrication of Bioceramic Bone Scaffolds for Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Liu, Fwu-Hsing

    2014-10-01

    In this study, microhydroxyapatite and nanosilica sol were used as the raw materials for fabrication of bioceramic bone scaffold using selective laser sintering technology in a self-developed 3D Printing apparatus. When the fluidity of ceramic slurry is matched with suitable laser processing parameters, a controlled pore size of porous bone scaffold can be fabricated under a lower laser energy. Results shown that the fabricated scaffolds have a bending strength of 14.1 MPa, a compressive strength of 24 MPa, a surface roughness of 725 nm, a pore size of 750 ?m, an apparent porosity of 32%, and a optical density of 1.8. Results indicate that the mechanical strength of the scaffold can be improved after heat treatment at 1200 °C for 2 h, while simultaneously increasing surface roughness conducive to osteoprogenitor cell adhesion. MTT method and SEM observations confirmed that bone scaffolds fabricated under the optimal manufacturing process possess suitable biocompatibility and mechanical properties, allowing smooth adhesion and proliferation of osteoblast-like cells. Therefore, they have great potential for development in the field of tissue engineering.

  5. Nanoparticle scaffolds for syngas-fed solid oxide fuel cells

    SciTech Connect

    Boldrin, Paul; Ruiz-Trejo, Enrique; Yu, Jingwen; Gruar, Robert I.; Tighe, Christopher J.; Chang, Kee-Chul; Ilavsky, Jan; Darr, Jawwad A.; Brandon, Nigel

    2014-12-17

    Incorporation of nanoparticles into devices such as solid oxide fuel cells (SOFCs) may provide benefits such as higher surface areas or finer control over microstructure. However, their use with traditional fabrication techniques such as screen-printing is problematic. Here, we show that mixing larger commercial particles with nanoparticles allows traditional ink formulation and screen-printing to be used while still providing benefits of nanoparticles such as increased porosity and lower sintering temperatures. SOFC anodes were produced by impregnating ceria–gadolinia (CGO) scaffolds with nickel nitrate solution. The scaffolds were produced from inks containing a mixture of hydrothermally-synthesised nanoparticle CGO, commercial CGO and polymeric pore formers. The scaffolds were heat-treated at either 1000 or 1300 °C, and were mechanically stable. In situ ultra-small X-ray scattering (USAXS) shows that the nanoparticles begin sintering around 900–1000 °C. Analysis by USAXS and scanning electron microscopy (SEM) revealed that the low temperature heat-treated scaffolds possessed higher porosity. Impregnated scaffolds were used to produce symmetrical cells, with the lower temperature heat-treated scaffolds showing improved gas diffusion, but poorer charge transfer. Using these scaffolds, lower temperature heat-treated cells of Ni–CGO/200 ?m YSZ/CGO-LSCF performed better at 700 °C (and below) in hydrogen, and performed better at all temperatures using syngas, with power densities of up to 0.15 W cm-2 at 800 °C. This approach has the potential to allow the use of a wider range of materials and finer control over microstructure.

  6. Biomimetic Scaffolds for Osteogenesis

    PubMed Central

    Yuan, Nance; Rezzadeh, Kameron S.; Lee, Justine C.

    2015-01-01

    Skeletal regenerative medicine emerged as a field of investigation to address large osseous deficiencies secondary to congenital, traumatic, and post-oncologic conditions. Although autologous bone grafts have been the gold standard for reconstruction of skeletal defects, donor site morbidity remains a significant limitation. To address these limitations, contemporary bone tissue engineering research aims to target delivery of osteogenic cells and growth factors in a defined three dimensional space using scaffolding material. Using bone as a template, biomimetic strategies in scaffold engineering unite organic and inorganic components in an optimal configuration to both support osteoinduction as well as osteoconduction. This article reviews the various structural and functional considerations behind the development of effective biomimetic scaffolds for osteogenesis and highlights strategies for enhancing osteogenesis. PMID:26413557

  7. Vascularization of wide pore agarose-gelatin cryogel scaffolds implanted subcutaneously in diabetic and non-diabetic mice.

    PubMed

    Bloch, K; Vanichkin, A; Damshkaln, L G; Lozinsky, V I; Vardi, P

    2010-03-01

    Polymeric scaffolds have been reported to promote angiogenesis, facilitating oxygen delivery; however, little is known about the effect of diabetes on the neo-vascularization of implanted polymeric scaffolds at subcutaneous (SC) sites. In this study we compare the effect of diabetes on scaffold vascularization following SC implantation into diabetic and non-diabetic mice. Wide pore agarose cryogel scaffolds with grafted gelatin were prepared by a two-step freezing procedure and subsequent thawing. The scaffolds were implanted subcutaneously into streptozoticin-induced diabetic mice and control, non-diabetic mice. The vascularization process was estimated using histological sections, in which endothelial cells were identified by Von Willebrand factor (vWF) and CD31 antigen staining and the pericyte layer was confirmed by alpha-smooth muscle actin (alpha-SMA) visualization. Comparative analysis showed a similar thickness of fibrous capsules around the vascularized scaffolds in both diabetic and non-diabetic animals. Intensive staining for alpha-SMA indicated the formation of mature blood vessels in the surrounding fibrous capsule and tissue invading the scaffold area. No statistically significant differences in capillary density and area occupied by blood vessels were found between diabetic and non-diabetic mice. In conclusion, the present study shows no adverse effects of diabetes on new blood vessel formation in SC implanted agarose cryogel scaffolds with grafted gelatin. PMID:19703598

  8. Plasma Surface Modification for Immobilization of Bone Morphogenic Protein-2 on Polycaprolactone Scaffolds

    NASA Astrophysics Data System (ADS)

    Kim, Byung Hoon; Myung, Sung Woon; Jung, Sang Chul; Ko, Yeong Mu

    2013-11-01

    The immobilization of recombinant human bone formation protein-2 (rhBMP-2) on polycaprolactone (PCL) scaffolds was performed by plasma polymerization. RhBMP-2, which induces osteoblast differentiation in various cell types, is a growth factor that plays an important role in bone formation and repair. The surface of the PCL scaffold was functionalized with the carboxyl groups of plasma-polymerized acrylic acid (PPAA) thin films. Plasma polymerization was carried out at a discharge power of 60 W at an acrylic acid flow rate of 7 sccm for 5 min. The PPAA thin film exhibited moderate hydrophilic properties and possessed a high density of carboxyl groups. Carboxyl groups and rhBMP-2 on the PCL scaffolds surface were identified by attenuated total reflection Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The alkaline phosphatase activity assay showed that the rhBMP-2 immobilized PCL scaffold increased the level of MG-63 cell differentiation. Plasma surface modification for the preparation of biomaterials, such as biofunctionalized polymer scaffolds, can be used for the binding of bioactive molecules in tissue engineering.

  9. Mesoporous bioactive glass doped-poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) composite scaffolds with 3-dimensionally hierarchical pore networks for bone regeneration.

    PubMed

    Yang, Shengbing; Wang, Jing; Tang, Liangji; Ao, Haiyong; Tan, Honglue; Tang, Tingting; Liu, Changsheng

    2014-04-01

    Scaffolds play a critical role in bone tissue engineering. Composite scaffolds made of biodegradable polymers and bioactive inorganic compounds have demonstrated superior properties in bone defect repair. In this study, highly bioactive, resorbable poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx)-based scaffolds were prepared using combinational 3-dimensional (3D) printing and surface-doping protocol. Structural and morphological characterization of the composite scaffolds demonstrated the homogenous surface-coating of mesoporous bioactive glass (MBG) throughout their porous framework. These hierarchical scaffolds showed bioactivity superior to that of scaffolds made of pure PHBHHx. MBG coating appeared to provide a better environment for human mesenchymal stem cells (hMSCs) attachment, activity, and osteogenic differentiation. Our study indicates that MBG-coated PHBHHx (PHBM) scaffolds may be excellent candidates for use in bone tissue engineering. PMID:24441182

  10. Development of Composite Scaffolds for Load-Bearing Segmental Bone Defects

    PubMed Central

    2013-01-01

    The need for a suitable tissue-engineered scaffold that can be used to heal load-bearing segmental bone defects (SBDs) is both immediate and increasing. During the past 30 years, various ceramic and polymer scaffolds have been investigated for this application. More recently, while composite scaffolds built using a combination of ceramics and polymeric materials are being investigated in a greater number, very few products have progressed from laboratory benchtop studies to preclinical testing in animals. This review is based on an exhaustive literature search of various composite scaffolds designed to serve as bone regenerative therapies. We analyzed the benefits and drawbacks of different composite scaffold manufacturing techniques, the properties of commonly used ceramics and polymers, and the properties of currently investigated synthetic composite grafts. To follow, a comprehensive review of in vivo models used to test composite scaffolds in SBDs is detailed to serve as a guide to design appropriate translational studies and to identify the challenges that need to be overcome in scaffold design for successful translation. This includes selecting the animal type, determining the anatomical location within the animals, choosing the correct study duration, and finally, an overview of scaffold performance assessment. PMID:23984363

  11. Novel chitosan/collagen scaffold containing transforming growth factor-{beta}1 DNA for periodontal tissue engineering

    SciTech Connect

    Zhang Yufeng; Cheng Xiangrong . E-mail: Xiangrongcheng@hotmail.com; Wang Jiawei; Wang Yining; Shi Bin; Huang Cui; Yang Xuechao; Liu Tongjun

    2006-05-26

    The current rapid progression in tissue engineering and local gene delivery system has enhanced our applications to periodontal tissue engineering. In this study, porous chitosan/collagen scaffolds were prepared through a freeze-drying process, and loaded with plasmid and adenoviral vector encoding human transforming growth factor-{beta}1 (TGF-{beta}1). These scaffolds were evaluated in vitro by analysis of microscopic structure, porosity, and cytocompatibility. Human periodontal ligament cells (HPLCs) were seeded in this scaffold, and gene transfection could be traced by green fluorescent protein (GFP). The expression of type I and type III collagen was detected with RT-PCR, and then these scaffolds were implanted subcutaneously into athymic mice. Results indicated that the pore diameter of the gene-combined scaffolds was lower than that of pure chitosan/collagen scaffold. The scaffold containing Ad-TGF-{beta}1 exhibited the highest proliferation rate, and the expression of type I and type III collagen up-regulated in Ad-TGF-{beta}1 scaffold. After implanted in vivo, EGFP-transfected HPLCs not only proliferated but also recruited surrounding tissue to grow in the scaffold. This study demonstrated the potential of chitosan/collagen scaffold combined Ad-TGF-{beta}1 as a good substrate candidate in periodontal tissue engineering.

  12. Preparation of foam-like carbon nanotubes/hydroxyapatite composite scaffolds with superparamagnetic properties

    NASA Astrophysics Data System (ADS)

    Lu, X. Y.; Qiu, T.; Wang, X. F.; Zhang, M.; Gao, X. L.; Li, R. X.; Lu, X.; Weng, J.

    2012-12-01

    In this paper, the foam-like composite scaffolds composed of hydroxyapatite (HA) and carbon nanotubes (CNTs) were prepared by a new method, where a polymer impregnating method was used for porous HA-based scaffold and a chemical vapor deposition (CVD) method was used for the growth of CNTs from the HA-based scaffold. The process produces the CNTs/HA scaffolds that have a foam-like structure with better mechanical property, better microstructure and a high degree of interconnection. A favorable pore size with big pores of 1-2 mm and small pores of 20-300 ?m for osteoconduction and bone ingrowth is presented in these scaffolds. About 2 wt% multi-walled CNTs with the diameter of 60-100 nm are observed to be in situ grown from deficient nano-HA crystallites. Magnetic measurement exhibits these scaffolds are superparamagnetic with a saturation magnetization of 1.14 emu g-1 at a room temperature, benefiting the scaffolds to take up growth factors in vivo, stem cell or other bioactive molecules easily. This new type of CNTs/HA scaffolds is expected to have a promising applications in bone tissue engineering, targeted drug delivery system and other biomedical fields.

  13. Enhancing Human Islet Transplantation by Localized Release of Trophic Factors From PLG Scaffolds

    PubMed Central

    Hlavaty, K. A.; Gibly, R. F.; Zhang, X.; Rives, C. B.; Graham, J. G.; Lowe, W. L.; Luo, X.; Shea, L. D.

    2014-01-01

    Islet transplantation represents a potential cure for type 1 diabetes, yet the clinical approach of intrahepatic delivery is limited by the microenvironment. Microporous scaffolds enable extrahepatic transplantation, and the microenvironment can be designed to enhance islet engraftment and function. We investigated localized trophic factor delivery in a xenogeneic human islet to mouse model of islet transplantation. Double emulsion microspheres containing exendin-4 (Ex4) or insulin-like growth factor-1 (IGF-1) were incorporated into a layered scaffold design consisting of porous outer layers for islet transplantation and a center layer for sustained factor release. Protein encapsulation and release were dependent on both the polymer concentration and the identity of the protein. Proteins retained bioactivity upon release from scaffolds in vitro. A minimal human islet mass transplanted on Ex4-releasing scaffolds demonstrated significant improvement and prolongation of graft function relative to blank scaffolds carrying no protein, and the release profile significantly impacted the duration over which the graft functioned. Ex4-releasing scaffolds enabled better glycemic control in animals subjected to an intraperitoneal glucose tolerance test. Scaffolds releasing IGF-1 lowered blood glucose levels, yet the reduction was insufficient to achieve euglycemia. Ex4-delivering scaffolds provide an extrahepatic transplantation site for modulating the islet microenvironment to enhance islet function posttransplant. PMID:24909237

  14. The influence of prefreezing temperature on pore structure in freeze-dried beta-TCP scaffolds.

    PubMed

    Lin, Liulan; Wang, Zhikun; Zhou, Liping; Hu, Qingxi; Fang, Minglun

    2013-01-01

    A combined method of tricalcium phosphate (TCP) scaffold production, which comprised negative mold and scaffold fabrication, was reported in this study. The negative mold structure was designed by computer and fabricated by fused deposition modeling (FDM) technology, while the TCP scaffold was produced by freeze-drying technology under different prefreezing temperatures of -10 degrees C, -30 degrees C, and -86 degrees C and thermal treatment to get beta-TCP. The scaffold structure was evaluated with X-ray, scanning electron microscopy (SEM), compressive mechanical testing, and micro-computerized tomography (micro-CT). The cell-scaffold interaction was studied by culturing dog bone marrow stromal cells (BMSCs) on the scaffolds and assessing differentiated BMSC function by measuring cellular alkaline phosphatase (ALP) activity. The results showed good interconnectivity and good pore distribution with the pore size ranging from 50 to 250 microm and compressive modulus of 1.18 MPa at a prefreezing temperatures of -10 degrees C. In vitro cell culture results indicated that the porous scaffolds were not toxic to bone cells. These results demonstrate that rapid prototyping and freeze-drying technologies for creating beta-TCP scaffolds are promising for bone tissue engineering. PMID:23516955

  15. Study of the electrospun PLA/silk fibroin-gelatin composite nanofibrous scaffold for tissue engineering.

    PubMed

    Gui-Bo, Yin; You-Zhu, Zhang; Shu-Dong, Wang; De-Bing, Shi; Zhi-Hui, Dong; Wei-Guo, Fu

    2010-04-01

    In this article, a nanofibrous composite scaffold of poly L-lactic acid(PLA)/silk fibroin(SF)-gelatin was fabricated by multilayer electrospinning. To investigate the feasibility of PLA/SF-gelatin use as scaffolds, the porosity and mechanical properties were examined; in particular, the biocompatibilities were evaluated in vivo and in vitro by the means of cell adhesion and cytotoxicity testing, short-term subcutaneous implantation testing, and acute hemolysis testing according to the requirements of ISO 10993. The results showed the scaffold achieved the desirable levels of pliability (elastic up to 7.3% strain) and the appropriate breaking strength (2.22 MPa). The porosity of the SF-gelatin layer was 87% and the pore diameter was 142 nm. After 12 days of cultivation, SEM observation demonstrated the scaffold was nontoxic, biocompatible, and capable of supporting 3T3 mouse fibroblasts attachment, spreading, and growth. The hemolysis test proved the scaffolds with hemolytic rates from 3.1 to 4.5%. The subcutaneous implantation test indicated minor inflammatory reactions surrounding the scaffolds and biodegradation were initially observed in about 3 months. The desired porous structure, strong and pliable properties, combined with the ability of PLA/SF-gelatin scaffold to support cell growth in vitro, especially excellent biocompatibility in vivo, suggested potential application for tissue engineering scaffolds. PMID:19536837

  16. Biocompatibility of hydroxyapatite scaffolds processed by lithography-based additive manufacturing.

    PubMed

    Tesavibul, Passakorn; Chantaweroad, Surapol; Laohaprapanon, Apinya; Channasanon, Somruethai; Uppanan, Paweena; Tanodekaew, Siriporn; Chalermkarnnon, Prasert; Sitthiseripratip, Kriskrai

    2015-10-16

    The fabrication of hydroxyapatite scaffolds for bone tissue engineering applications by using lithography-based additive manufacturing techniques has been introduced due to the abilities to control porous structures with suitable resolutions. In this research, the use of hydroxyapatite cellular structures, which are processed by lithography-based additive manufacturing machine, as a bone tissue engineering scaffold was investigated. The utilization of digital light processing system for additive manufacturing machine in laboratory scale was performed in order to fabricate the hydroxyapatite scaffold, of which biocompatibilities were eventually evaluated by direct contact and cell-culturing tests. In addition, the density and compressive strength of the scaffolds were also characterized. The results show that the hydroxyapatite scaffold at 77% of porosity with 91% of theoretical density and 0.36 MPa of the compressive strength are able to be processed. In comparison with a conventionally sintered hydroxyapatite, the scaffold did not present any cytotoxic signs while the viability of cells at 95.1% was reported. After 14 days of cell-culturing tests, the scaffold was able to be attached by pre-osteoblasts (MC3T3-E1) leading to cell proliferation and differentiation. The hydroxyapatite scaffold for bone tissue engineering was able to be processed by the lithography-based additive manufacturing machine while the biocompatibilities were also confirmed. PMID:26484553

  17. Preparation and characterization of (PCL-crosslinked-PEG)/hydroxyapatite as bone tissue engineering scaffolds.

    PubMed

    Koupaei, Narjes; Karkhaneh, Akbar; Daliri Joupari, Morteza

    2015-12-01

    In this study, interconnected porous bioactive scaffolds were synthesized for bone tissue engineering. At the first step, poly( ?-caprolactone) (PCL) diols were diacrylated with acryloyl chloride. Then, the scaffolds were synthesized by radical crosslinking reaction of PCL and poly(ethyleneglycol) (PEG) diacrylates in the presence of hydroxyapatite (HA) particles. Morphological, swelling, thermal, and mechanical characteristics as well as degradability of the scaffolds were investigated. Results showed that increasing the ratio of PEG to PCL led to significant increase of swelling ratio and degradation rate, and decrease of crystallinity and compressive modulus of the networks, respectively. It was found that the incorporation of HA particles with the polymer matrices resulted in an augmented crystallinity, a decreased swelling ratio, and also a significantly increased compressive modulus of the networks. Cytocompatability and osteoconductivity of the scaffolds were assessed by MTT and alkaline phosphatase (ALP) assays, respectively. The results confirmed the cytocompatible nature of PCL/PEG/HA scaffolds with no toxicity. MG-63 cells attached and spread on the pore walls offered by the scaffolds. PCL/PEG/HA scaffolds compared with PCL/PEG ones showed higher ALP activity. Thus, the results indicated that the PCL/PEG/HA scaffolds have the potential of being used as promising substrates in bone tissue engineering. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3919-3926, 2015. PMID:26015080

  18. Polycaprolactone scaffolds fabricated with an advanced electrohydrodynamic direct-printing method for bone tissue regeneration.

    PubMed

    Ahn, Seung Hyun; Lee, Hyeong Jin; Kim, Geun Hyung

    2011-12-12

    Electrohydrodynamic (EHD) direct writing has been used in diverse microelectromechanical systems and various supplemental methods for biotechnology and electronics. In this work, we expanded the use of EHD-induced direct writing to fabricate 3D biomedical scaffolds designed as porous structures for bone tissue engineering. To prepare the scaffolds, we modified a grounded target used in conventional EHD direct printing using a poly(ethylene oxide) solution bath, elastically cushioning the plotted struts to prevent crumbling. The fabricated scaffolds were assessed for not only physical properties including surface roughness and water uptake ability but also biological capabilities by culturing osteoblast-like cells (MG63) for the EHD-plotted polycaprolactone (PCL) scaffold. The EHD-scaffolds showed significantly roughened surface and enhanced water-absorption ability (400% increase) compared with the pure rapid-prototyped PCL. The results of cell viability, alkaline phosphatase activity, and mineralization analyses showed significantly enhanced biological properties of the scaffold (20 times the cell viability and 6 times the mineralization) compared with the scaffolds fabricated using RP technology. Because of the results, the modified EHD direct-writing process can be a promising method for fabricating 3D biomedical scaffolds in tissue engineering. PMID:22070169

  19. Minimally invasive approach to the repair of injured skeletal muscle with a shape-memory scaffold.

    PubMed

    Wang, Lin; Cao, Lan; Shansky, Janet; Wang, Zheng; Mooney, David; Vandenburgh, Herman

    2014-08-01

    Repair of injured skeletal muscle by cell therapies has been limited by poor survival of injected cells. Use of a carrier scaffold delivering cells locally, may enhance in vivo cell survival, and promote skeletal muscle regeneration. Biomaterial scaffolds are often implanted into muscle tissue through invasive surgeries, which can result in trauma that delays healing. Minimally invasive approaches to scaffold implantation are thought to minimize these adverse effects. This hypothesis was addressed in the context of a severe mouse skeletal muscle injury model. A degradable, shape-memory alginate scaffold that was highly porous and compressible was delivered by minimally invasive surgical techniques to injured tibialis anterior muscle. The scaffold controlled was quickly rehydrated in situ with autologous myoblasts and growth factors (either insulin-like growth factor-1 (IGF-1) alone or IGF-1 with vascular endothelial growth factor (VEGF)). The implanted scaffolds delivering myoblasts and IGF-1 significantly reduced scar formation, enhanced cell engraftment, and improved muscle contractile function. The addition of VEGF to the scaffold further improved functional recovery likely through increased angiogenesis. Thus, the delivery of myoblasts and dual local release of VEGF and IGF-1 from degradable scaffolds implanted through a minimally invasive procedure effectively promoted the functional regeneration of injured skeletal muscle. PMID:24769909

  20. Enhancement of neurite outgrowth in neuron cancer stem cells by growth on 3-D collagen scaffolds.

    PubMed

    Chen, Chih-Hao; Kuo, Shyh Ming; Liu, Guei-Sheung; Chen, Wan-Nan U; Chuang, Chin-Wen; Liu, Li-Feng

    2012-11-01

    Collagen is one component of the extracellular matrix that has been widely used for constructive remodeling to facilitate cell growth and differentiation. The 3-D distribution and growth of cells within the porous scaffold suggest a clinical significance for nerve tissue engineering. In the current study, we investigated proliferation and differentiation of neuron cancer stem cells (NCSCs) on a 3-D porous collagen scaffold that mimics the natural extracellular matrix. We first generated green fluorescence protein (GFP) expressing NCSCs using a lentiviral system to instantly monitor the transitions of morphological changes during growth on the 3-D scaffold. We found that proliferation of GFP-NCSCs increased, and a single cell mass rapidly grew with unrestricted expansion between days 3 and 9 in culture. Moreover, immunostaining with neuronal nuclei (NeuN) revealed that NCSCs grown on the 3-D collagen scaffold significantly enhanced neurite outgrowth. Our findings confirmed that the 80 ?m porous collagen scaffold could enhance attachment, viability and differentiation of the cancer neural stem cells. This result could provide a new application for nerve tissue engineering and nerve regeneration. PMID:23047009

  1. Precision Extruding Deposition for Freeform Fabrication of PCL and PCL-HA Tissue Scaffolds

    NASA Astrophysics Data System (ADS)

    Shor, L.; Yildirim, E. D.; Güçeri, S.; Sun, W.

    Computer-aided tissue engineering approach was used to develop a novel Precision Extrusion Deposition (PED) process to directly fabricate Polycaprolactone (PCL) and composite PCL/Hydroxyapatite (PCL-HA) tissue scaffolds. The process optimization was carried out to fabricate both PCL and PCL-HA (25% concentration by weight of HA) with a controlled pore size and internal pore structure of the 0°/90° pattern. Two groups of scaffolds having 60 and 70% porosity and with pore sizes of 450 and 750 microns, respectively, were evaluated for their morphology and compressive properties using Scanning Electron Microscopy (SEM) and mechanical testing. The surface modification with plasma was conducted on PCL scaffold to increase the cellular attachment and proliferation. Our results suggested that inclusion of HA significantly increased the compressive modulus from 59 to 84 MPa for 60% porous scaffolds and from 30 to 76 MPa for 70% porous scaffolds. In vitro cell-scaffolds interaction study was carried out using primary fetal bovine osteoblasts to assess the feasibility of scaffolds for bone tissue engineering application. In addition, the results in surface hydrophilicity and roughness show that plasma surface modification can increase the hydrophilicity while introducing the nano-scale surface roughness on PCL surface. The cell proliferation and differentiation were calculated by Alamar Blue assay and by determining alkaline phosphatase activity. The osteoblasts were able to migrate and proliferate over the cultured time for both PCL as well as PCL-HA scaffolds. Our study demonstrated the viability of the PED process to the fabricate PCL and PCL-HA composite scaffolds having necessary mechanical property, structural integrity, controlled pore size and pore interconnectivity desired for bone tissue engineering.

  2. Rapid fabrication of rigid biodegradable scaffolds by excimer laser mask projection technique: a comparison between 248 and 308 nm

    NASA Astrophysics Data System (ADS)

    Beke, S.; Anjum, F.; Ceseracciu, L.; Romano, I.; Athanassiou, A.; Diaspro, A.; Brandi, F.

    2013-03-01

    High-resolution photocrosslinking of the biodegradable poly(propylene fumarate) (PPF) and diethyl fumarate (DEF), using pulsed laser light at 248 and 308 nm is presented. The curing depth can be modulated between a few hundreds of nm and a few ?m when using 248 nm and ten to a hundred ?m when using 308 nm. By adjusting the total fluence (pulse numbers×laser fluence) dose and the weight ratios of PPF, DEF, and the photoinitiator in the photocrosslinkable mixtures, the height of polymerized structures can be precisely tuned. The lateral resolution is evaluated by projecting a pattern of a grid with a specified line width and line spacing. Young’s modulus of the cured parts is measured and found to be several GPa for both wavelengths, high enough to support bone formation. Several 2D and 2.5D microstructures, as well as porous 3D scaffolds fabricated by a layer-by-layer method, are presented. The results demonstrate that excimer laser-based photocuring is suitable for the fabrication of stiff and biocompatible structures with defined patterns of micrometer resolution in all three spatial dimensions.

  3. Periodontal regeneration with nano-hyroxyapatite-coated silk scaffolds in dogs

    PubMed Central

    Yang, Cheryl; Lee, Jung-Seok; Jung, Ui-Won; Seo, Young-Kwon; Park, Jung-Keug

    2013-01-01

    Purpose In this study, we investigated the effect of silk scaffolds on one-wall periodontal intrabony defects. We conjugated nano-hydroxyapatite (nHA) onto a silk scaffold and then seeded periodontal ligament cells (PDLCs) or dental pulp cells (DPCs) onto the scaffold. Methods Five dogs were used in this study. Bilateral 4 mm×2 mm (depth×mesiodistal width), one-wall intrabony periodontal defects were surgically created on the distal side of the mandibular second premolar and the mesial side of the mandibular fourth premolar. In each dog, four of the defects were separately and randomly assigned to the following groups: the PDLC-cultured scaffold transplantation group (PDLC group), the DPC-cultured scaffold transplantation group (DPC group), the normal saline-soaked scaffold transplantation group, and the control group. The animals were euthanized following an 8-week healing interval for clinical, scanning electron microscopy (SEM), and histologic evaluations. Results There was no sign of inflammation or other clinical signs of postoperative complications. The examination of cell-seeded constructs by SEM provided visual confirmation of the favorable characteristics of nHA-coated silk scaffolds for tissue engineering. The scaffolds exhibited a firm connective porous structure in cross section, and after PDLCs and DPCs were seeded onto the scaffolds and cultured for 3 weeks, the attachment of well-spread cells and the formation of extracellular matrix (ECM) were observed. The histologic analysis revealed that a well-maintained grafted volume was present at all experimental sites for 8 weeks. Small amounts of inflammatory cells were seen within the scaffolds. The PDLC and DPC groups did not have remarkably different histologic appearances. Conclusions These observations indicate that nHA-coated silk scaffolds can be considered to be potentially useful biomaterials for periodontal regeneration. PMID:24455445

  4. Preparation of poly(ethylene glycol)/polylactide hybrid fibrous scaffolds for bone tissue engineering

    PubMed Central

    Ni, PeiYan; Fu, ShaoZhi; Fan, Min; Guo, Gang; Shi, Shuai; Peng, JinRong; Luo, Feng; Qian, ZhiYong

    2011-01-01

    Polylactide (PLA) electrospun fibers have been reported as a scaffold for bone tissue engineering application, however, the great hydrophobicity limits its broad application. In this study, the hybrid amphiphilic poly(ethylene glycol) (PEG)/hydrophobic PLA fibrous scaffolds exhibited improved morphology with regular and continuous fibers compared to corresponding blank PLA fiber mats. The prepared PEG/PLA fibrous scaffolds favored mesenchymal stem cell (MSC) attachment and proliferation by providing an interconnected porous extracellular environment. Meanwhile, MSCs can penetrate into the fibrous scaffold through the interstitial pores and integrate well with the surrounding fibers, which is very important for favorable application in tissue engineering. More importantly, the electrospun hybrid PEG/PLA fibrous scaffolds can enhance MSCs to differentiate into bone-associated cells by comprehensively evaluating the representative markers of the osteogenic procedure with messenger ribonucleic acid quantitation and protein analysis. MSCs on the PEG/PLA fibrous scaffolds presented better differentiation potential with higher messenger ribonucleic acid expression of the earliest osteogenic marker Cbfa-1 and mid-stage osteogenic marker Col I. The significantly higher alkaline phosphatase activity of the PEG/PLA fibrous scaffolds indicated that these can enhance the differentiation of MSCs into osteoblast-like cells. Furthermore, the higher messenger ribonucleic acid level of the late osteogenic differentiation markers OCN (osteocalcin) and OPN (osteopontin), accompanied by the positive Alizarin red S staining, showed better maturation of osteogenic induction on the PEG/PLA fibrous scaffolds at the mineralization stage of differentiation. After transplantation into the thigh muscle pouches of rats, and evaluating the inflammatory cells surrounding the scaffolds and the physiological characteristics of the surrounding tissues, the PEG/PLA scaffolds presented good biocompatibility. Based on the good cellular response and excellent osteogenic potential in vitro, as well as the biocompatibility with the surrounding tissues in vivo, the electrospun PEG/PLA fibrous scaffolds could be one of the most promising candidates in bone tissue engineering. PMID:22163160

  5. Three-dimensional printing of soy protein scaffolds for tissue regeneration.

    PubMed

    Chien, Karen B; Makridakis, Emmanuella; Shah, Ramille N

    2013-06-01

    Fabricating three-dimensional (3D) porous scaffolds with controlled structure and geometry is crucial for tissue regeneration. To date, exploration in printing 3D natural protein scaffolds is limited. In this study, soy protein slurry was successfully printed using the 3D Bioplotter to form scaffolds. A method to verify the structural integrity of resulting scaffolds during printing was developed. This process involved measuring the mass extrusion flow rate of the slurry from the instrument, which was directly affected by the extrusion pressure and the soy protein slurry properties. The optimal mass flow rate for printing soy slurry at 27°C was 0.0072±0.0002?g/s. The addition of dithiothreitol to soy slurries demonstrated the importance of disulfide bonds in forming solid structures upon printing. Resulting Bioplotted soy protein scaffolds were cured using 95% ethanol and post-treated using dehydrothermal treatment (DHT), a combination of freeze-drying and DHT, and chemical crosslinking using 1-ethyl-3-(3 dimethylaminopropyl)carbodiimide (EDC) chemistry. Surface morphologies of the different treatment groups were characterized using scanning electron microscopy. Scaffold properties, including relative crosslink density, mass loss upon rinsing, and compressive modulus revealed that EDC crosslinked scaffolds were the most robust with moduli of approximately 4?kPa. Scaffold geometry (45° and 90° layer rotations) affected the mechanical properties for DHT and EDC crosslinked scaffolds. Seeding efficiency of human mesenchymal stem cells (hMSC) was highest for nontreated and thermally treated scaffolds, and all scaffolds supported hMSC viability over time. PMID:23102234

  6. Mathematical Abstraction through Scaffolding

    ERIC Educational Resources Information Center

    Ozmantar, Mehmet Fatih; Roper, Tom

    2004-01-01

    This paper examines the role of scaffolding in the process of abstraction. An activity-theoretic approach to abstraction in context is taken. This examination is carried out with reference to verbal protocols of two 17 year-old students working together on a task connected to sketching the graph of |f|x|)|. Examination of the data suggests that…

  7. Scaffold Assisted Chromosome Condensation

    E-print Network

    Poonen, Bjorn

    resembling the X-shape of the chromosome #12;Great Thanks to: PRIMES Prof. Leonid Mirny Geoffrey FudenbergScaffold Assisted Chromosome Condensation: Molecular Dynamics Simulations Dong-Gil Shin MIT PRIMES May 21, 2011 #12;Mitosis and Chromosome Condensation Interphase Prophase Metaphase Anaphase Telophase

  8. Scaffold pore space modulation through intelligent design of dissolvable microparticles.

    PubMed

    Liebschner, Michael A K; Wettergreen, Matthew

    2012-01-01

    The goal of this area of research is to manipulate the pore space of scaffolds through the application of an intelligent design concept on dissolvable microparticles. To accomplish this goal, we developed an efficient and repeatable process for fabrication of microparticles from multiple materials using a combination of rapid prototyping (RP) and soft lithography. Phase changed 3D printing was used to create masters for PDMS molds. A photocrosslinkable polymer was then delivered into these molds to make geometrically complex 3D microparticles. This repeatable process has demonstrated to generate the objects with greater than 95% repeatability with complete pattern transfer. This process was illustrated for three different shapes of various complexities. The shapes were based on the extrusion of 2D shapes. This may allow simplification of the fabrication process in the future combined with a direct transfer of the findings. Altering the shapes of particles used for porous scaffold fabrication will allow for tailoring of the pore shapes, and therefore their biological function within a porous tissue engineering scaffold. Through permeation experiments, we have shown that the pore geometry may alter the permeability coefficient of scaffolds while influencing mechanical properties to a lesser extent. By selecting different porogen shapes, the nutrition transport and scaffold degradation can be significantly influenced with minimal effect on the mechanical integrity of the construct. In addition, the different shapes may allow a control of drug release by modifying their surface-to-volume ratio, which could modulate drug delivery over time. While soft lithography is currently used with photolithography, its high precision is offset by high cost of production. The employment of RP to a specific resolution offers a much less expensive alternative with increased throughput due to the speed of current RP systems. PMID:22692605

  9. Relevance of fiber integrated gelatin-nanohydroxyapatite composite scaffold for bone tissue regeneration

    NASA Astrophysics Data System (ADS)

    Halima Shamaz, Bibi; Anitha, A.; Vijayamohan, Manju; Kuttappan, Shruthy; Nair, Shantikumar; Nair, Manitha B.

    2015-10-01

    Porous nanohydroxyapatite (nanoHA) is a promising bone substitute, but it is brittle, which limits its utility for load bearing applications. To address this issue, herein, biodegradable electrospun microfibrous sheets of poly(L-lactic acid)-(PLLA)-polyvinyl alcohol (PVA) were incorporated into a gelatin-nanoHA matrix which was investigated for its mechanical properties, the physical integration of the fibers with the matrix, cell infiltration, osteogenic differentiation and bone regeneration. The inclusion of sacrificial fibers like PVA along with PLLA and leaching resulted in improved cellular infiltration towards the center of the scaffold. Furthermore, the treatment of PLLA fibers with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide enhanced their hydrophilicity, ensuring firm anchorage between the fibers and the gelatin-HA matrix. The incorporation of PLLA microfibers within the gelatin-nanoHA matrix reduced the brittleness of the scaffolds, the effect being proportional to the number of layers of fibrous sheets in the matrix. The proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells was augmented on the fibrous scaffolds in comparison to those scaffolds devoid of fibers. Finally, the scaffold could promote cell infiltration, together with bone regeneration, upon implantation in a rabbit femoral cortical defect within 4 weeks. The bone regeneration potential was significantly higher when compared to commercially available HA (Surgiwear™). Thus, this biomimetic, porous, 3D composite scaffold could be offered as a promising candidate for bone regeneration in orthopedics.

  10. Carbon nanotubes reinforced poly(L-lactide) scaffolds fabricated by thermally induced phase separation.

    PubMed

    Ma, Haiyun; Xue, Li

    2015-01-16

    In tissue engineering, porous nanocomposite scaffolds can potentially mimic aspects of the nanoscale architecture of the extra-cellular matrix, as well as enhance the mechanical properties required for successful weight-bearing implants. In this paper, we demonstrate that highly porous thermoplastic poly(L-lactide) nanocomposite scaffolds containing different types of functionalized multi-walled carbon nanotubes (CNTs). The nanocomposite scaffolds were manufactured by a thermally induced phase separation method. This experiment produced an uniform distribution of CNTs throughout the scaffold without obvious aggregations for funtionalized CNTs filled scaffolds by scanning electron microscope observation. The CNTs were frequently located on the pore surface, forming rough, hairy nano-textures. The pore size was reduced with the increasing of CNT loading. Parts of PLLA matrix was induced into nanofibrous structures from solid-walled state, which reduced the crystallinity of the PLLA characterized by DSC measurement. The CNT incorporation significantly improved the compression modulus of the nanocomposite scaffolds, especially the functionalized CNTs. The capacity of protein adsorption is significantly improved when the concentration of the CNTs was higher than 1.0 wt.% and the cell attachment was also enhanced by the addition of CNTs, especially N-CNT. PMID:25525708

  11. Carbon nanotubes reinforced poly(L-lactide) scaffolds fabricated by thermally induced phase separation

    NASA Astrophysics Data System (ADS)

    Ma, Haiyun; Xue, Li

    2015-01-01

    In tissue engineering, porous nanocomposite scaffolds can potentially mimic aspects of the nanoscale architecture of the extra-cellular matrix, as well as enhance the mechanical properties required for successful weight-bearing implants. In this paper, we demonstrate that highly porous thermoplastic poly(L-lactide) nanocomposite scaffolds containing different types of functionalized multi-walled carbon nanotubes (CNTs). The nanocomposite scaffolds were manufactured by a thermally induced phase separation method. This experiment produced an uniform distribution of CNTs throughout the scaffold without obvious aggregations for funtionalized CNTs filled scaffolds by scanning electron microscope observation. The CNTs were frequently located on the pore surface, forming rough, hairy nano-textures. The pore size was reduced with the increasing of CNT loading. Parts of PLLA matrix was induced into nanofibrous structures from solid-walled state, which reduced the crystallinity of the PLLA characterized by DSC measurement. The CNT incorporation significantly improved the compression modulus of the nanocomposite scaffolds, especially the functionalized CNTs. The capacity of protein adsorption is significantly improved when the concentration of the CNTs was higher than 1.0 wt.% and the cell attachment was also enhanced by the addition of CNTs, especially N-CNT.

  12. Bi-layered calcium phosphate cement-based composite scaffold mimicking natural bone structure

    NASA Astrophysics Data System (ADS)

    He, Fupo; Ye, Jiandong

    2013-08-01

    In this study, a core/shell bi-layered calcium phosphate cement (CPC)-based composite scaffold with adjustable compressive strength, which mimicked the structure of natural cortical/cancellous bone, was fabricated. The dense tubular CPC shell was prepared by isostatic pressing CPC powder with a specially designed mould. A porous CPC core with unidirectional lamellar pore structure was fabricated inside the cavity of dense tubular CPC shell by unidirectional freeze casting, followed by infiltration of poly(lactic-co-glycolic acid) and immobilization of collagen. The compressive strength of bi-layered CPC-based composite scaffold can be controlled by varying thickness ratio of dense layer to porous layer. Compared to the scaffold without dense shell, the pore interconnection of bi-layered scaffold was not obviously compromised because of its high unidirectional interconnectivity but poor three dimensional interconnectivity. The in vitro results showed that the rat bone marrow stromal cells attached and proliferated well on the bi-layered CPC-based composite scaffold. This novel bi-layered CPC-based composite scaffold is promising for bone repair.

  13. Relevance of fiber integrated gelatin-nanohydroxyapatite composite scaffold for bone tissue regeneration.

    PubMed

    Shamaz, Bibi Halima; Anitha, A; Vijayamohan, Manju; Kuttappan, Shruthy; Nair, Shantikumar; Nair, Manitha B

    2015-10-01

    Porous nanohydroxyapatite (nanoHA) is a promising bone substitute, but it is brittle, which limits its utility for load bearing applications. To address this issue, herein, biodegradable electrospun microfibrous sheets of poly(L-lactic acid)-(PLLA)-polyvinyl alcohol (PVA) were incorporated into a gelatin-nanoHA matrix which was investigated for its mechanical properties, the physical integration of the fibers with the matrix, cell infiltration, osteogenic differentiation and bone regeneration. The inclusion of sacrificial fibers like PVA along with PLLA and leaching resulted in improved cellular infiltration towards the center of the scaffold. Furthermore, the treatment of PLLA fibers with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide enhanced their hydrophilicity, ensuring firm anchorage between the fibers and the gelatin-HA matrix. The incorporation of PLLA microfibers within the gelatin-nanoHA matrix reduced the brittleness of the scaffolds, the effect being proportional to the number of layers of fibrous sheets in the matrix. The proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells was augmented on the fibrous scaffolds in comparison to those scaffolds devoid of fibers. Finally, the scaffold could promote cell infiltration, together with bone regeneration, upon implantation in a rabbit femoral cortical defect within 4 weeks. The bone regeneration potential was significantly higher when compared to commercially available HA (Surgiwear™). Thus, this biomimetic, porous, 3D composite scaffold could be offered as a promising candidate for bone regeneration in orthopedics. PMID:26373968

  14. Fabrication of hierarchically porous materials and nanowires through coffee ring effect.

    PubMed

    Khapli, Sachin; Rianasari, Ina; Blanton, Thomas; Weston, James; Gilardetti, Rachael; Neiva, Rodrigo; Tovar, Nick; Coelho, Paulo G; Jagannathan, Ramesh

    2014-12-10

    We report a versatile method for the fabrication of nanowires and hierarchical porous materials from a wide variety of ceramic materials such as CaCO3, ZnO, CuO, Co3O4, Co-doped ZnO, and Ag2O. The method consists of evaporation of CO2-enriched water microdroplets (diameter ?3 ?m) deposited from an aerosol onto heated substrates (T = 120 °C). A variety of porous scaffolds with 1-3 ?m sized pores can be generated by tuning the process conditions. Subsequent sintering of the scaffolds is shown to generate nanosized pores in the walls of the porous scaffold creating a dual hierarchy of pore sizes (?50 nm and 1-3 ?m). We propose a mechanism for the formation of scaffolds based on the coffee-ring effect during the evaporation of microdroplets. Ostwald-ripening of CaCO3 scaffolds prepared without sintering yields scaffold structures consisting of two-dimensional crystals of CaCO3 that are one unit cell thick. The favorable application of CaCO3 scaffolds for the enhancement of bone healing around titanium implants with improved biocompatibility is also demonstrated. PMID:25376596

  15. Enhanced in vitro osteoblast differentiation on TiO2 scaffold coated with alginate hydrogel containing simvastatin

    PubMed Central

    Pullisaar, Helen; Tiainen, Hanna; Landin, Maria A; Lyngstadaas, Ståle P; Reseland, Janne E; Østrup, Esben

    2013-01-01

    The aim of this study was to develop a three-dimensional porous bone graft material as vehicle for simvastatin delivery and to investigate its effect on primary human osteoblasts from three donors. Highly porous titanium dioxide (TiO2) scaffolds were submerged into simvastatin containing alginate solution. Microstructure of scaffolds, visualized by scanning electron microscopy and micro-computed tomography, revealed an evenly distributed alginate layer covering the surface of TiO2 scaffold struts. Progressive and sustained simvastatin release was observed for up to 19 days. No cytotoxic effects on osteoblasts were observed by scaffolds with simvastatin when compared to scaffolds without simvastatin. Expression of osteoblast markers (collagen type I alpha 1, alkaline phosphatase, bone morphogenetic protein 2, osteoprotegerin, vascular endothelial growth factor A and osteocalcin) was quantified using real-time reverse transcriptase–polymerase chain reaction. Secretion of osteoprotegerin, vascular endothelial growth factor A and osteocalcin was analysed by multiplex immunoassay (Luminex). The relative expression and secretion of osteocalcin was significantly increased by cells cultured on scaffolds with 10 µM simvastatin when compared to scaffolds without simvastatin after 21 days. In addition, secretion of vascular endothelial growth factor A was significantly enhanced from cells cultured on scaffolds with both 10 nM and 10 µM simvastatin when compared to scaffolds without simvastatin at day 21. In conclusion, the results indicate that simvastatin-coated TiO2 scaffolds can support a sustained release of simvastatin and induce osteoblast differentiation. The combination of the physical properties of TiO2 scaffolds with the osteogenic effect of simvastatin may represent a new strategy for bone regeneration in defects where immediate load is wanted or unavailable. PMID:24555011

  16. Mechanical properties of bioactive glass (13-93) scaffolds fabricated by robotic deposition for structural bone repair

    PubMed Central

    Liu, Xin; Rahaman, Mohamed N.; Hilmas, Gregory E.; Bal, B. Sonny

    2013-01-01

    There is a need to develop synthetic scaffolds for repairing large defects in load-bearing bones. Bioactive glasses have attractive properties as a scaffold material for bone repair, but data on their mechanical properties are limited. The objective of the present study was to comprehensively evaluate the mechanical properties of strong porous scaffolds of silicate 13-93 bioactive glass fabricated by robocasting. As-fabricated scaffolds with a grid-like microstructure (porosity = 47%; filament diameter = 330 ?m; pore width = 300) were tested in compressive and flexural loading to determine their strength, elastic modulus, Weibull modulus, fatigue resistance, and fracture toughness. Scaffolds were also tested in compression after they were immersed in simulated body fluid (SBF) in vitro or implanted in a rat subcutaneous model in vivo. As fabricated, the scaffolds had a strength = 86 ± 9 MPa, elastic modulus = 13 ± 2 GPa, and a Weibull modulus = 12 when tested in compression. In flexural loading, the strength, elastic modulus, and Weibull modulus were 11 ± 3 MPa, 13 ± 2 GPa, and 6, respectively. In compression, the as-fabricated scaffolds had a mean fatigue life of ~106 cycles when tested in air at room temperature or in phosphate-buffered saline at 37 °C under cyclic stresses of 1–10 MPa or 2–20 MPa. The compressive strength of the scaffolds decreased markedly during the first 2 weeks of immersion in SBF or implantation in vivo, but more slowly thereafter. The brittle mechanical response of the scaffolds in vitro changed to an elasto-plastic response after implantation for longer than 2–4 weeks in vivo. In addition to providing critically needed data for designing bioactive glass scaffolds, the results are promising for the application of these strong porous scaffolds in loaded bone repair. PMID:23438862

  17. Liquid-liquid two phase systems for the production of porous hydrogels and hydrogel microspheres for biomedical applications: A tutorial review

    PubMed Central

    Elbert, Donald L.

    2010-01-01

    Macroporous hydrogels may have direct applications in regenerative medicine as scaffolds to support tissue formation. Hydrogel microspheres may be used as drug delivery vehicles or as building blocks to assemble modular scaffolds. A variety of techniques exist to produce macroporous hydrogels and hydrogel microspheres. A subset of these relies on liquid-liquid two phase systems. Within this subset, vastly different types of polymerization processes are found. In this review, the history, terminology and classification of liquid-liquid two phase polymerization and crosslinking are described. Instructive examples of hydrogel microsphere and macroporous scaffold formation by precipitation/dispersion, emulsion and suspension polymerizations are used to illustrate the nature of these processes. The role of the kinetics of phase separation in determining the morphology of scaffolds and microspheres is also delineated. Brief descriptions of miniemulsion, microemulsion polymerization and ionotropic gelation are also included. PMID:20659596

  18. Polymerization of perfluorobutadiene

    NASA Technical Reports Server (NTRS)

    Newman, J.; Toy, M. S.

    1970-01-01

    Diisopropyl peroxydicarbonate dissolved in liquid perfluorobutadiene is conducted in a sealed vessel at the autogenous pressure of polymerization. Reaction temperature, ratio of catalyst to monomer, and amount of agitation determine degree of polymerization and product yield.

  19. Skeletal Muscle Regeneration on Protein-Grafted and Microchannel-Patterned Scaffold for Hypopharyngeal Tissue Engineering

    PubMed Central

    Shen, Zhisen; Guo, Shanshan; Ye, Dong; Chen, Jingjing; Kang, Cheng; Qiu, Shejie; Lu, Dakai; Li, Qun; Xu, Kunjie; Lv, Jingjing

    2013-01-01

    In the field of tissue engineering, polymeric materials with high biocompatibility like polylactic acid and polyglycolic acid have been widely used for fabricating living constructs. For hypopharynx tissue engineering, skeletal muscle is one important functional part of the whole organ, which assembles the unidirectionally aligned myotubes. In this study, a polyurethane (PU) scaffold with microchannel patterns was used to provide aligning guidance for the seeded human myoblasts. Due to the low hydrophilicity of PU, the scaffold was grafted with silk fibroin (PU-SF) or gelatin (PU-Gel) to improve its cell adhesion properties. Scaffolds were observed to degrade slowly over time, and their mechanical properties and hydrophilicities were improved through the surface grafting. Also, the myoblasts seeded on PU-SF had the higher proliferative rate and better differentiation compared with those on the control or PU-Gel. Our results demonstrate that polyurethane scaffolds seeded with myoblasts hold promise to guide hypopharynx muscle regeneration. PMID:24175281

  20. Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation.

    PubMed

    Bergemann, Claudia; Cornelsen, Matthias; Quade, Antje; Laube, Thorsten; Schnabelrauch, Matthias; Rebl, Henrike; Weißmann, Volker; Seitz, Hermann; Nebe, Barbara

    2016-02-01

    The generation of hybrid materials based on ?-tricalcium phosphate (TCP) and various biodegradable polymers like poly(l-lactide-co-d,l-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA - improvement of compressive strength of calcium phosphate scaffolds - is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10mm hybrid scaffold were dynamically cultivated for 14days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. PMID:26652403

  1. ?-Tricalcium phosphate/poly(glycerol sebacate) scaffolds with robust mechanical property for bone tissue engineering.

    PubMed

    Yang, Kai; Zhang, Jing; Ma, Xiaoyu; Ma, Yifan; Kan, Chao; Ma, Haiyan; Li, Yulin; Yuan, Yuan; Liu, Changsheng

    2015-11-01

    Despite good biocompatibility and osteoconductivity, porous ?-TCP scaffolds still lack the structural stability and mechanical robustness, which greatly limit their application in the field of bone regeneration. The hybridization of ?-TCP with conventional synthetic biodegradable PLA and PCL only produced a limited toughening effect due to the plasticity of the polymers in nature. In this study, a ?-TCP/poly(glycerol sebacate) scaffold (?-TCP/PGS) with well interconnected porous structure and robust mechanical property was prepared. Porous ?-TCP scaffold was first prepared with polyurethane sponge as template and then impregnated into PGS pre-polymer solution with moderate viscosity, followed by in situ heat crosslinking and freezing-drying process. The results indicated that the freezing-drying under vacuum process could further facilitate crosslinking of PGS and formation of Ca(2+)-COO(-) ionic complexing and thus synergistically improved the mechanical strength of the ?-TCP/PGS with in situ heat crosslinking. Particularly, the ?-TCP/PGS with 15% PGS content after heat crosslinking at 130°C and freezing-drying at -50°C under vacuum exhibited an elongation at break of 375±25% and a compressive strength of 1.73MPa, 3.7-fold and 200-fold enhancement compared to the ?-TCP, respectively. After the abrupt drop of compressive load, the ?-TCP/PGS scaffolds exhibited a full recovery of their original shape. More importantly, the PGS polymer in the ?-TCP/PGS scaffolds could direct the biomineralization of Ca/P from particulate shape into a nanofiber-interweaved structure. Furthermore, the ?-TCP/PGS scaffolds allowed for cell penetration and proliferation, indicating a good cytobiocompatibility. It is believed that ?-TCP/PGS scaffolds have great potential application in rigid tissue regeneration. PMID:26249563

  2. Fabrication using a rapid prototyping system and in vitro characterization of PEG-PCL-PLA scaffolds for tissue engineering.

    PubMed

    Hoque, M E; Hutmacher, D W; Feng, W; Li, S; Huang, M-H; Vert, M; Wong, Y S

    2005-01-01

    In the field of tissue engineering new polymers are needed to fabricate scaffolds with specific properties depending on the targeted tissue. This work aimed at designing and developing a 3D scaffold with variable mechanical strength, fully interconnected porous network, controllable hydrophilicity and degradability. For this, a desktop-robot-based melt-extrusion rapid prototyping technique was applied to a novel tri-block co-polymer, namely poly(ethylene glycol)-block-poly(epsilon-caprolactone)-block-poly(DL-lactide), PEG-PCL-P(DL)LA. This co-polymer was melted by electrical heating and directly extruded out using computer-controlled rapid prototyping by means of compressed purified air to build porous scaffolds. Various lay-down patterns (0/30/60/90/120/150 degrees, 0/45/90/135 degrees, 0/60/120 degrees and 0/90 degrees) were produced by using appropriate positioning of the robotic control system. Scanning electron microscopy and micro-computed tomography were used to show that 3D scaffold architectures were honeycomb-like with completely interconnected and controlled channel characteristics. Compression tests were performed and the data obtained agreed well with the typical behavior of a porous material undergoing deformation. Preliminary cell response to the as-fabricated scaffolds has been studied with primary human fibroblasts. The results demonstrated the suitability of the process and the cell biocompatibility of the polymer, two important properties among the many required for effective clinical use and efficient tissue-engineering scaffolding. PMID:16366339

  3. Fabrication of Cell Patches Using Biodegradable Scaffolds with a Hexagonal Array of Interconnected Pores (SHAIPs)

    PubMed Central

    Zhang, Yu Shrike; Yao, Junjie; Wang, Lihong V.; Xia, Younan

    2013-01-01

    Cell patches are widely used for healing injuries on the surfaces or interfaces of tissues such as those of epidermis and myocardium. Here we report a novel type of porous scaffolds made of poly(D,L-lactic-co-glycolic acid) for fabricating cell patches. The scaffolds have a single layer of spherical pores arranged in a unique hexagonal pattern and are therefore referred to as “scaffolds with a hexagonal array of interconnected pores (SHAIPs)”. SHAIPs contain both uniform pores and interconnecting windows that can facilitate the exchange of biomacromolecules, ensure homogeneous cell seeding, and promote cell migration. As a proof-of-concept demonstration, we have created skeletal muscle patches with a thickness of approximately 150 ?m using SHAIPs. The myoblasts seeded in the scaffolds maintained high viability and were able to differentiate into multi-nucleated myotubes. Moreover, neovasculature could efficiently develop into the patches upon subcutaneous implantation in vivo. PMID:24443593

  4. Synthesis, characterization, and biological evaluation of gelatin-based scaffolds

    E-print Network

    Giuseppe Tronci

    2011-01-11

    This thesis presents the development of entropy-elastic gelatin based networks in the form of films or scaffolds. The materials have good prospects for biomedical applications, especially in the context of bone regeneration. Entropy-elastic gelatin based hydrogel films with varying crosslinking densities were prepared with tailored mechanical properties. Gelatin was covalently crosslinked in water above its sol gel transition, which suppressed the gelatin chain helicity. Amorphous films were prepared with tailorable degrees of swelling and wet state Young's modulus. The knowledge gained with this bulk material was transferred to the integrated process of foaming and crosslinking to obtain porous gelatin-based scaffolds. A gelatin solution was foamed in the presence of saponin and the resulting foam was fixed by chemical crosslinking with a diisocyanate. The scaffolds were analyzed in the dry state by micro computed tomography (\\mu CT, porosity: 65\\pm 11-73\\pm 14 vol.-%), and scanning electron microscopy (SEM, pore size: 117\\pm 28-166 \\pm 32 \\mu m). After equilibration with water, the scaffolds were form-stable and displayed shape recovery after removal of mechanical loads. The composition dependent compression moduli (Ec: 10 50 kPa) were comparable to the bulk micromechanical Young's moduli, which were measured by atomic force microscopy (AFM). The hydrolytic degradation profile could be adjusted, and a controlled decrease of mechanical properties was observed. The scaffold cytotoxicity and immunologic responses were analyzed in vitro. Indirect eluate tests were carried out with L929 cells so that fully cytocompatible scaffolds were obtained. Furthermore, the material immune response was investigated in vitro. Minimal material endotoxin contamination was successfully achieved (<0.5 EU/mL) by using low-endotoxin gelatin and performing all synthetic steps in cleanroom.

  5. Development of dual scale scaffolds via direct polymer melt deposition and electrospinning for applications in tissue regeneration.

    PubMed

    Park, Suk Hee; Kim, Taek Gyoung; Kim, Hyo Chan; Yang, Dong-Yol; Park, Tae Gwan

    2008-09-01

    The objective of this study was the fabrication of highly functionalized polymeric three-dimensional (3D) structures characterized by nano and microfibers for use as an extracellular matrix-like tissue engineering scaffold. A hybrid process utilizing direct polymer melt deposition (DPMD) and an electrospinning method were employed to obtain the structure. Each microfibrous layer of the scaffold was built using the DPMD process in accordance with computer-aided design modeling data considering some structural points such as pore size, pore interconnectivity and fiber diameter. Between the layers of the three-dimensional structure, polycaprolactone/collagen nanofiber matrices were deposited via an electrospinning process. To evaluate the fabricated scaffolds, chondrocytes were seeded and cultured within the developed scaffolds for 10 days, and the levels of cell adhesion and proliferation were monitored. The results showed that the polymeric scaffolds with nanofiber matrices fabricated using the proposed hybrid process provided favorable conditions for cell adhesion and proliferation. These conditions can be attributed to enhanced cytocompatibility of the scaffold due to surficial nanotopography in the scaffold, chemical composition by use of a functional biocomposite, and an enlarged inner surface of the structure for cell attachment and growth. PMID:18458008

  6. The Effect of Alendronate Loaded Biphasic Calcium Phosphate Scaffolds on Bone Regeneration in a Rat Tibial Defect Model.

    PubMed

    Park, Kwang-Won; Yun, Young-Pil; Kim, Sung Eun; Song, Hae-Ryong

    2015-01-01

    This study investigated the effect of alendronate (Aln) released from biphasic calcium phosphate (BCP) scaffolds. We evaluated the in vitro osteogenic differentiation of Aln/BCP scaffolds using MG-63 cells and the in vivo bone regenerative capability of Aln/BCP scaffolds using a rat tibial defect model with radiography, micro-computed tomography (CT), and histological examination. In vitro studies included the surface morphology of BCP and Aln-loaded BCP scaffolds visualized using field-emission scanning electron microscope, release kinetics of Aln from BCP scaffolds, alkaline phosphatase (ALP) activity, calcium deposition, and gene expression. The in vitro studies showed that sustained release of Aln from the BCP scaffolds consisted of porous microstructures, and revealed that MG-63 cells cultured on Aln-loaded BCP scaffolds showed significantly increased ALP activity, calcium deposition, and gene expression compared to cells cultured on BCP scaffolds. The in vivo studies using radiograph and histology examination revealed abundant callus formation and bone maturation at the site in the Aln/BCP groups compared to the control group. However, solid bony bridge formation was not observed at plain radiographs until 8 weeks. Micro-CT analysis revealed that bone mineral density and bone formation volume were increased over time in an Aln concentration-dependent manner. These results suggested that Aln/BCP scaffolds have the potential for controlling the release of Aln and enhance bone formation and mineralization. PMID:26561810

  7. The Effect of Alendronate Loaded Biphasic Calcium Phosphate Scaffolds on Bone Regeneration in a Rat Tibial Defect Model

    PubMed Central

    Park, Kwang-Won; Yun, Young-Pil; Kim, Sung Eun; Song, Hae-Ryong

    2015-01-01

    This study investigated the effect of alendronate (Aln) released from biphasic calcium phosphate (BCP) scaffolds. We evaluated the in vitro osteogenic differentiation of Aln/BCP scaffolds using MG-63 cells and the in vivo bone regenerative capability of Aln/BCP scaffolds using a rat tibial defect model with radiography, micro-computed tomography (CT), and histological examination. In vitro studies included the surface morphology of BCP and Aln-loaded BCP scaffolds visualized using field-emission scanning electron microscope, release kinetics of Aln from BCP scaffolds, alkaline phosphatase (ALP) activity, calcium deposition, and gene expression. The in vitro studies showed that sustained release of Aln from the BCP scaffolds consisted of porous microstructures, and revealed that MG-63 cells cultured on Aln-loaded BCP scaffolds showed significantly increased ALP activity, calcium deposition, and gene expression compared to cells cultured on BCP scaffolds. The in vivo studies using radiograph and histology examination revealed abundant callus formation and bone maturation at the site in the Aln/BCP groups compared to the control group. However, solid bony bridge formation was not observed at plain radiographs until 8 weeks. Micro-CT analysis revealed that bone mineral density and bone formation volume were increased over time in an Aln concentration-dependent manner. These results suggested that Aln/BCP scaffolds have the potential for controlling the release of Aln and enhance bone formation and mineralization. PMID:26561810

  8. A novel biomimetic composite scaffold hybridized with mesenchymal stem cells in repair of rat bone defects models.

    PubMed

    Xu, Caixia; Su, Peiqiang; Wang, Yingjun; Chen, Xiaofeng; Meng, Yongchun; Liu, Chang; Yu, Xinbing; Yang, Xuhui; Yu, Weihua; Zhang, Xiuming; Xiang, Andy Peng

    2010-11-01

    In this study, the in vivo bone-regenerative potential of a novel bioactive glass-collagen-hyaluronic acid-Phosphatidylserine (BG-COL-HYA-PS) composite scaffold hybridized with mesenchymal stem cells (MSCs) was investigated in a rat bone defect model. HrGFP-labeled MSCs were cultured for 2 weeks on the BG-COL-HYA-PS scaffold before implantation into the defect. A cell-free scaffold and an untreated defect were used as controls. The regeneration process was evaluated by histology, X-ray, and mechanical rigidity experiments at different time points post-implantation. The results revealed that BG-COL-HYA-PS scaffold exhibited a low inflammatory response and foreign body response within 3 weeks. At week 6, those responses disappeared following the resorption of scaffolds and the formation of new bone. Compared with the pure scaffold or empty group, the introduction of MSCs into the porous scaffold dramatically enhanced the efficiency of the new bone formation and biomechanical property of the femur. In addition, the transplanted MSCs could survive for up to 3 weeks or longer. The results demonstrated that the BG-COL-HYA-PS scaffold was biocompatible and osteoconductive and the transplanted MSCs with the scaffold enhanced the healing of the bone defect. PMID:20665678

  9. [Research on the mechanical properties of bone scaffold reinforced by magnesium alloy/bioceramics composite with stereolithography double channels].

    PubMed

    Li, Changhai; Lian, Qin; Zhuang, Pei; Wang, Junzhong; Li, Dichen

    2015-02-01

    Focusing on the poor mechanical strength of porous bioceramics bone scaffold, and taking into account of the good mechanical properties of biodegradable magnesium alloy, we proposed a novel method to fabricate magnesium alloy/bioceramics composite bone scaffold with stereolithography double channels. Firstly, a scaffold structure without mutually connected double channels was designed. Then, an optimized bioceramics scaffold was fabricated according to stereolithography and gel-casing. Molten AZ31 magnesium alloy was perfused into the secondary channel of scaffold by low-pressure casting, and magnesium alloy/bioceramics composite bone scaffold was obtained when magnesium alloy was solidified. The compression test showed that the strength of bioceramics scaffold with only one channel and without magnesium alloy was (9.76 ± 0.64) MPa, while the strength of magnesium alloy/bioceramics composite scaffold with double channels was (17.25 ± 0.88) MPa. It can be concluded that the magnesium alloy/bioceramics composite is obviously able to improve the scaffold strength. PMID:25997270

  10. A preliminary study of acoustic propagation in thick foam tissue scaffolds composed of poly(lactic-co-glycolic acid)

    E-print Network

    N. G. Parker; M. L. Mather; S. P. Morgan; M. J. W. Povey

    2010-02-26

    The exclusive ability of acoustic waves to probe the structural, mechanical and fluidic properties of foams may offer novel approaches to characterise the porous scaffolds employed in tissue engineering. Motivated by this we conduct a preliminary investigation into the acoustic properties of a typical biopolymer and the feasibility of acoustic propagation within a foam scaffold thereof. Focussing on poly(lactic-co-glycolic acid), we use a pulse-echo method to determine the longitudinal speed of sound, whose temperature-dependence reveals the glass transition of the polymer. Finally, we demonstrate the first topographic and tomographic acoustic images of polymer foam tissue scaffolds.

  11. Arrayed Hollow Channels in Silk-based Scaffolds Provide Functional Outcomes for Engineering Critically-sized Tissue Constructs

    PubMed Central

    Rnjak-Kovacina, Jelena; Wray, Lindsay S.; Golinski, Julianne M.; Kaplan, David L.

    2014-01-01

    In the field of regenerative medicine there is a need for scaffolds that support large, critically-sized tissue formation. Major limitations in reaching this goal are the delivery of oxygen and nutrients throughout the bulk of the engineered tissue as well as host tissue integration and vascularization upon implantation. To address these limitations we previously reported the development of a porous scaffold platform made from biodegradable silk protein that contains an array of vascular-like structures that extend through the bulk of the scaffold. Here we report that the hollow channels play a pivotal role in enhancing cell infiltration, delivering oxygen and nutrients to the scaffold bulk, and promoting in vivo host tissue integration and vascularization. The unique features of this protein biomaterial system, including the vascular structures and tunable material properties, render this scaffold a robust and versatile tool for implementation in a variety of tissue engineering, regenerative medicine and disease modeling applications. PMID:25395920

  12. Scaffolding in Technology-Enhanced Science Education 

    E-print Network

    Wu, Hui-Ling

    2011-08-08

    This dissertation focuses on the effectiveness of scaffolding in technology-enhanced science learning environments, and specifically the relative merits of computer- and teacher-based scaffolding in science inquiry. Scaffolding is an instructional...

  13. 49 CFR 214.109 - Scaffolding.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.109...Scaffolding used in connection with railroad bridge maintenance, inspection, testing...scaffold and scaffold component, except suspension ropes and guardrail systems,...

  14. 49 CFR 214.109 - Scaffolding.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.109...Scaffolding used in connection with railroad bridge maintenance, inspection, testing...scaffold and scaffold component, except suspension ropes and guardrail systems,...

  15. 49 CFR 214.109 - Scaffolding.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.109 Scaffolding. (a) Scaffolding used in connection with railroad bridge maintenance, inspection, testing, and... hazard. (e) All scaffold design, construction, and repair shall be completed by competent...

  16. 49 CFR 214.109 - Scaffolding.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.109 Scaffolding. (a) Scaffolding used in connection with railroad bridge maintenance, inspection, testing, and... hazard. (e) All scaffold design, construction, and repair shall be completed by competent...

  17. 49 CFR 214.109 - Scaffolding.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY Bridge Worker Safety Standards § 214.109 Scaffolding. (a) Scaffolding used in connection with railroad bridge maintenance, inspection, testing, and... hazard. (e) All scaffold design, construction, and repair shall be completed by competent...

  18. Bioactive glass-reinforced bioceramic ink writing scaffolds: sintering, microstructure and mechanical behavior.

    PubMed

    Shao, Huifeng; Yang, Xianyan; He, Yong; Fu, Jianzhong; Liu, Limin; Ma, Liang; Zhang, Lei; Yang, Guojing; Gao, Changyou; Gou, Zhongru

    2015-01-01

    The densification of pore struts in bioceramic scaffolds is important for structure stability and strength reliability. An advantage of ceramic ink writing is the precise control over the microstructure and macroarchitecture. However, the use of organic binder in such ink writing process would heavily affect the densification of ceramic struts and sacrifice the mechanical strength of porous scaffolds after sintering. This study presents a low-melt-point bioactive glass (BG)-assisted sintering strategy to overcome the main limitations of direct ink writing (extrusion-based three-dimensional printing) and to produce high-strength calcium silicate (CSi) bioceramic scaffolds. The 1% BG-added CSi (CSi-BG1) scaffolds with rectangular pore morphology sintered at 1080 °C have a very small BG content, readily induce apatite formation, and show appreciable linear shrinkage (?21%), which is consistent with the composite scaffolds with less or more BG contents sintered at either the same or a higher temperature. These CSi-BG1 scaffolds also possess a high elastic modulus (?350 MPa) and appreciable compressive strength (?48 MPa), and show significant strength enhancement after exposure to simulated body fluid-a performance markedly superior to those of pure CSi scaffolds. Particularly, the honeycomb-pore CSi-BG1 scaffolds show markedly higher compressive strength (?88 MPa) than the scaffolds with rectangular, parallelogram, and Archimedean chord pore structures. It is suggested that this approach can potentially facilitate the translation of ceramic ink writing and BG-assisted sintering of bioceramic scaffold technologies to the in situ bone repair. PMID:26355654

  19. Intervertebral Disc Tissue Engineering with Natural Extracellular Matrix-Derived Biphasic Composite Scaffolds

    PubMed Central

    Xu, Baoshan; Xu, Haiwei; Wu, Yaohong; Li, Xiulan; Zhang, Yang; Ma, Xinlong; Yang, Qiang

    2015-01-01

    Tissue engineering has provided an alternative therapeutic possibility for degenerative disc diseases. However, we lack an ideal scaffold for IVD tissue engineering. The goal of this study is to fabricate a novel biomimetic biphasic scaffold for IVD tissue engineering and evaluate the feasibility of developing tissue-engineered IVD in vitro and in vivo. In present study we developed a novel integrated biphasic IVD scaffold using a simple freeze-drying and cross-linking technique of pig bone matrix gelatin (BMG) for the outer annulus fibrosus (AF) phase and pig acellular cartilage ECM (ACECM) for the inner nucleus pulposus (NP) phase. Histology and SEM results indicated no residual cells remaining in the scaffold that featured an interconnected porous microstructure (pore size of AF and NP phase 401.4±13.1 ?m and 231.6±57.2 ?m, respectively). PKH26-labeled AF and NP cells were seeded into the scaffold and cultured in vitro. SEM confirmed that seeded cells could anchor onto the scaffold. Live/dead staining showed that live cells (green fluorescence) were distributed in the scaffold, with no dead cells (red fluorescence) being found. The cell—scaffold constructs were implanted subcutaneously into nude mice and cultured for 6 weeks in vivo. IVD-like tissue formed in nude mice as confirmed by histology. Cells in hybrid constructs originated from PKH26-labeled cells, as confirmed by in vivo fluorescence imaging system. In conclusion, the study demonstrates the feasibility of developing a tissue-engineered IVD in vivo with a BMG- and ACECM-derived integrated AF-NP biphasic scaffold. As well, PKH26 fluorescent labeling with in vivo fluorescent imaging can be used to track cells and analyse cell—scaffold constructs in vivo. PMID:25894203

  20. A novel bone scaffold design approach based on shape function and all-hexahedral mesh refinement.

    PubMed

    Cai, Shengyong; Xi, Juntong; Chua, Chee Kai

    2012-01-01

    Tissue engineering is the application of interdisciplinary knowledge in the building and repairing of tissues. Generally, an engineered tissue is a combination of living cells and a support structure called a scaffold. The scaffold provides support for bone-producing cells and can be used to heal or replace a defective bone. In this chapter, a novel bone scaffold design approach based on shape function and an all-hexahedral mesh refinement method is presented. Based on the shape function in the finite element method, an all-hexahedral mesh is used to design a porous bone scaffold. First, the individual pore based on the subdivided individual element is modeled; then, the Boolean operation union among the pores is used to generate the whole pore model of TE bone scaffold; finally, the bone scaffold which contains various irregular pores can be modeled by the Boolean operation difference between the solid model and the whole pore model. From the SEM images, the pore size distribution in the native bone is not randomly distributed and there are gradients for pore size distribution. Therefore, a control approach for pore size distribution in the bone scaffold based on the hexahedral mesh refinement is also proposed in this chapter. A well-defined pore size distribution can be achieved based on the fact that a hexahedral element size distribution can be obtained through an all-hexahedral mesh refinement and the pore morphology and size are under the control of the hexahedral element. The designed bone scaffold can be converted to a universal 3D file format (such as STL or STEP) which could be used for rapid prototyping (RP). Finally, 3D printing (Spectrum Z510), a type of RP system, is adopted to fabricate these bone scaffolds. The successfully fabricated scaffolds validate the novel computer-aided design approach in this research. PMID:22692603

  1. Interfacial Formation of Porous Membranes with Poly(ethylene glycol) in a Microfluidic Environment

    E-print Network

    Beebe, David J.

    . This liquid wall can be used to conduct an interfacial polymerization, which then fabricates a thin membrane.8­17 In conventional, bulk interfacial polymerization, a microporous support membrane is typically used to provideInterfacial Formation of Porous Membranes with Poly(ethylene glycol) in a Microfluidic Environment

  2. Poly(3-hydroxybutyrate) multifunctional composite scaffolds for tissue engineering applications.

    PubMed

    Misra, Superb K; Ansari, Tahera I; Valappil, Sabeel P; Mohn, Dirk; Philip, Sheryl E; Stark, Wendelin J; Roy, Ipsita; Knowles, Jonathan C; Salih, Vehid; Boccaccini, Aldo R

    2010-04-01

    Poly(3-hydroxybutyrate) (P(3HB)) foams exhibiting highly interconnected porosity (85% porosity) were prepared using a unique combination of solvent casting and particulate leaching techniques by employing commercially available sugar cubes as porogen. Bioactive glass (BG) particles of 45S5 Bioglass grade were introduced in the scaffold microstructure, both in micrometer ((m-BG), <5 microm) and nanometer ((n-BG), 30 nm) sizes. The in vitro bioactivity of the P(3HB)/BG foams was confirmed within 10 days of immersion in simulated body fluid and the foams showed high level of protein adsorption. The foams interconnected porous microstructure proved to be suitable for MG-63 osteoblast cell attachment and proliferation. The foams implanted in rats as subcutaneous implants resulted in a non-toxic and foreign body response after one week of implantation. In addition to showing bioactivity and biocompatibility, the P(3HB)/BG composite foams also exhibited bactericidal properties, which was tested on the growth of Staphylococcus aureus. An attempt was made at developing multifunctional scaffolds by incorporating, in addition to BG, selected concentrations of Vitamin E or/and carbon nanotubes. P(3HB) scaffolds with multifunctionalities (viz. bactericidal, bioactive, electrically conductive, antioxidative behaviour) were thus produced, which paves the way for next generation of advanced scaffolds for bone tissue engineering. PMID:20045554

  3. Carbohydrate scaffolds as glycosyltransferase inhibitors with in vivo antibacterial activity.

    PubMed

    Zuegg, Johannes; Muldoon, Craig; Adamson, George; McKeveney, Declan; Le Thanh, Giang; Premraj, Rajaratnam; Becker, Bernd; Cheng, Mu; Elliott, Alysha G; Huang, Johnny X; Butler, Mark S; Bajaj, Megha; Seifert, Joachim; Singh, Latika; Galley, Nicola F; Roper, David I; Lloyd, Adrian J; Dowson, Christopher G; Cheng, Ting-Jen; Cheng, Wei-Chieh; Demon, Dieter; Meyer, Evelyne; Meutermans, Wim; Cooper, Matthew A

    2015-01-01

    The rapid rise of multi-drug-resistant bacteria is a global healthcare crisis, and new antibiotics are urgently required, especially those with modes of action that have low-resistance potential. One promising lead is the liposaccharide antibiotic moenomycin that inhibits bacterial glycosyltransferases, which are essential for peptidoglycan polymerization, while displaying a low rate of resistance. Unfortunately, the lipophilicity of moenomycin leads to unfavourable pharmacokinetic properties that render it unsuitable for systemic administration. In this study, we show that using moenomycin and other glycosyltransferase inhibitors as templates, we were able to synthesize compound libraries based on novel pyranose scaffold chemistry, with moenomycin-like activity, but with improved drug-like properties. The novel compounds exhibit in vitro inhibition comparable to moenomycin, with low toxicity and good efficacy in several in vivo models of infection. This approach based on non-planar carbohydrate scaffolds provides a new opportunity to develop new antibiotics with low propensity for resistance induction. PMID:26194781

  4. Carbohydrate scaffolds as glycosyltransferase inhibitors with in vivo antibacterial activity

    PubMed Central

    Zuegg, Johannes; Muldoon, Craig; Adamson, George; McKeveney, Declan; Le Thanh, Giang; Premraj, Rajaratnam; Becker, Bernd; Cheng, Mu; Elliott, Alysha G.; Huang, Johnny X.; Butler, Mark S.; Bajaj, Megha; Seifert, Joachim; Singh, Latika; Galley, Nicola F.; Roper, David I.; Lloyd, Adrian J.; Dowson, Christopher G.; Cheng, Ting-Jen; Cheng, Wei-Chieh; Demon, Dieter; Meyer, Evelyne; Meutermans, Wim; Cooper, Matthew A.

    2015-01-01

    The rapid rise of multi-drug-resistant bacteria is a global healthcare crisis, and new antibiotics are urgently required, especially those with modes of action that have low-resistance potential. One promising lead is the liposaccharide antibiotic moenomycin that inhibits bacterial glycosyltransferases, which are essential for peptidoglycan polymerization, while displaying a low rate of resistance. Unfortunately, the lipophilicity of moenomycin leads to unfavourable pharmacokinetic properties that render it unsuitable for systemic administration. In this study, we show that using moenomycin and other glycosyltransferase inhibitors as templates, we were able to synthesize compound libraries based on novel pyranose scaffold chemistry, with moenomycin-like activity, but with improved drug-like properties. The novel compounds exhibit in vitro inhibition comparable to moenomycin, with low toxicity and good efficacy in several in vivo models of infection. This approach based on non-planar carbohydrate scaffolds provides a new opportunity to develop new antibiotics with low propensity for resistance induction. PMID:26194781

  5. Graphene oxide nanoflakes incorporated gelatin-hydroxyapatite scaffolds enhance osteogenic differentiation of human mesenchymal stem cells

    NASA Astrophysics Data System (ADS)

    Nair, Manitha; Nancy, D.; Krishnan, Amit G.; Anjusree, G. S.; Vadukumpully, Sajini; Nair, Shantikumar V.

    2015-04-01

    In this study, graphene oxide (GO) nanoflakes (0.5 and 1 wt%) were incorporated into a gelatin-hydroxyapatite (GHA) matrix through a freeze drying technique and its effect to enhance mechanical strength and osteogenic differentiation was studied. The GHA matrix with GO demonstrated less brittleness in comparison to GHA scaffolds. There was no significant difference in mechanical strength between GOGHA0.5 and GOGHA1.0 scaffolds. When the scaffolds were immersed in phosphate buffered saline (to mimic physiologic condition) for 60 days, around 50-60% of GO was released in sustained and linear manner and the concentration was within the toxicity limit as reported earlier. Further, GOGHA0.5 scaffolds were continued for cell culture experiments, wherein the scaffold induced osteogenic differentiation of human adipose derived mesenchymal stem cells without providing supplements like dexamethasone, L-ascorbic acid and ? glycerophosphate in the medium. The level of osteogenic differentiation of stem cells was comparable to those cultured on GHA scaffolds with osteogenic supplements. Thus biocompatible, biodegradable and porous GO reinforced gelatin-HA 3D scaffolds may serve as a suitable candidate in promoting bone regeneration in orthopaedics.

  6. Silk as a biocohesive sacrificial binder in the fabrication of hydroxyapatite load bearing scaffolds

    PubMed Central

    McNamara, Stephanie L.; Rnjak-Kovacina, Jelena; Schmidt, Daniel; Lo, Tim J.; Kaplan, David L.

    2014-01-01

    Limitations of current clinical methods for bone repair continue to fuel the demand for a high strength, bioactive bone replacement material. Recent attempts to produce porous scaffolds for bone regeneration have been limited by the intrinsic weakness associated with high porosity materials. In this study, ceramic scaffold fabrication techniques for potential use in load-bearing bone repairs have been developed using naturally derived silk from Bombyx mori. Silk was first employed for ceramic grain consolidation during green body formation, and later as a sacrificial polymer to impart porosity during sintering. These techniques allowed preparation of hydroxyapatite (HA) scaffolds that exhibited a wide range of mechanical and porosity profiles, with some displaying unusually high compressive strength up to 152.4 ± 9.1 MPa. Results showed that the scaffolds exhibited a wide range of compressive strengths and moduli (8.7 ± 2.7 MPa to 152.4 ± 9.1 MPa and 0.3 ± 0.1 GPa to 8.6 ± 0.3 GPa) with total porosities of up to 62.9 ± 2.7% depending on the parameters used for fabrication. Moreover, HA-silk scaffolds could be molded into large, complex shapes, and further machined post-sinter to generate specific three-dimensional geometries. Scaffolds supported bone marrow-derived mesenchymal stem cell attachment and proliferation, with no signs of cytotoxicity. Therefore, silk-fabricated HA scaffolds show promise for load bearing bone repair and regeneration needs. PMID:24881027

  7. Melt-electrospun polycaprolactone strontium-substituted bioactive glass scaffolds for bone regeneration.

    PubMed

    Ren, Jiongyu; Blackwood, Keith A; Doustgani, Amir; Poh, Patrina P; Steck, Roland; Stevens, Molly M; Woodruff, Maria A

    2014-09-01

    Polycaprolactone (PCL) is a resorbable polymer used extensively in bone tissue engineering owing to good structural properties and processability. Strontium-substituted bioactive glass (SrBG) has the ability to promote osteogenesis and may be incorporated into scaffolds intended for bone repair. Here, we describe for the first time, the development of a PCL-SrBG composite scaffold incorporating 10% (weight) of SrBG particles into PCL bulk, produced by the technique of melt electrospinning. We show that we are able to reproducibly manufacture composite scaffolds with an interconnected porous structure and, furthermore, these scaffolds were demonstrated to be noncytotoxic in vitro. Ions present in the SrBG component were shown to dissolve into cell culture media and promoted precipitation of a calcium phosphate layer on the scaffold surface which in turn led to noticeably enhanced alkaline phosphatase activity in MC3T3-E1 cells compared to PLC-only scaffolds. These results suggest that melt-electrospun PCL-SrBG composite scaffolds show potential to become effective bone graft substitutes. PMID:24133006

  8. Graphene oxide nanoflakes incorporated gelatin-hydroxyapatite scaffolds enhance osteogenic differentiation of human mesenchymal stem cells.

    PubMed

    Nair, Manitha; Nancy, D; Krishnan, Amit G; Anjusree, G S; Vadukumpully, Sajini; Nair, Shantikumar V

    2015-04-24

    In this study, graphene oxide (GO) nanoflakes (0.5 and 1 wt%) were incorporated into a gelatin-hydroxyapatite (GHA) matrix through a freeze drying technique and its effect to enhance mechanical strength and osteogenic differentiation was studied. The GHA matrix with GO demonstrated less brittleness in comparison to GHA scaffolds. There was no significant difference in mechanical strength between GOGHA0.5 and GOGHA1.0 scaffolds. When the scaffolds were immersed in phosphate buffered saline (to mimic physiologic condition) for 60 days, around 50-60% of GO was released in sustained and linear manner and the concentration was within the toxicity limit as reported earlier. Further, GOGHA0.5 scaffolds were continued for cell culture experiments, wherein the scaffold induced osteogenic differentiation of human adipose derived mesenchymal stem cells without providing supplements like dexamethasone, L-ascorbic acid and ? glycerophosphate in the medium. The level of osteogenic differentiation of stem cells was comparable to those cultured on GHA scaffolds with osteogenic supplements. Thus biocompatible, biodegradable and porous GO reinforced gelatin-HA 3D scaffolds may serve as a suitable candidate in promoting bone regeneration in orthopaedics. PMID:25824014

  9. Melt-electrospun polycaprolactone-strontium substituted bioactive glass scaffolds for bone regeneration.

    PubMed

    Ren, Jiongyu; Blackwood, Keith A; Doustgani, Amir; Poh, Patrina P; Steck, Roland; Stevens, Molly M; Woodruff, Maria A

    2013-10-01

    Polycaprolactone (PCL) is a resorbable polymer used extensively in bone tissue engineering owing to good structural properties and processability. Strontium substituted bioactive glass (SrBG) has the ability to promote osteogenesis and may be incorporated into scaffolds intended for bone repair. Here we describe for the first time, the development of a PCL-SrBG composite scaffold incorporating 10% (weight) of SrBG particles into PCL bulk, produced by the technique of melt-electrospinning. We show that we are able to reproducibly manufacture composite scaffolds with an interconnected porous structure and, furthermore, these scaffolds were demonstrated to be non-cytotoxic in vitro. Ions present in the SrBG component were shown to dissolve into cell culture media and promoted precipitation of a calcium phosphate layer on the scaffold surface which in turn led to noticeably enhanced alkaline phosphatase activity in MC3T3-E1 cells compared to PLC-only scaffolds. These results suggest that melt-electrospun PCL-SrBG composite scaffolds show potential to become effective bone graft substitutes. PMID:24123950

  10. Macroscale Properties of Porous Media from a Network Model of Bio lm Processes

    E-print Network

    Macroscale Properties of Porous Media from a Network Model of Bio#12;lm Processes Brian J. Suchomel porosity and permeability changes in a porous medium as a result of bio#12;lm buildup in the pore spaces. A bio#12;lm consists of bacteria and extracellular polymeric substances (EPS) bonded together

  11. Regenerated cellulose scaffolds: Preparation, characterization and toxicological evaluation.

    PubMed

    de Araújo Júnior, Adalberto M; Braido, Guilherme; Saska, Sybele; Barud, Hernane S; Franchi, Leonardo P; Assunção, Rosana M N; Scarel-Caminaga, Raquel M; Capote, Ticiana S O; Messaddeq, Younès; Ribeiro, Sidney J L

    2016-01-20

    Regenerated cellulose scaffolds (RCS) may be used as alloplastic materials for tissue repair. In this work, the RCS were obtained by viscose process and characterized by scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry analysis (TG). In vitro enzymatic degradation assay and toxicological assays were also evaluated. The physicochemical characterizations revealed the formation of a porous material with distinct thermal profile and crystallinity compared to pristine cellulose pulp. Enzymatic degradation assay revealed that lysozyme showed a mildest catalytic action when compared to cellulase, Tricoderma reesei (Tr). Nevertheless, both enzymes were efficient for degrading the RCS. RCS did not show cytotoxicity, mutagenic or genotoxic effects. The systematically characterization of this work suggests that RCS presented distinct features that make it a viable material for future studies related to the development of scaffolds for biological applications. PMID:26572426

  12. Variably porous structures

    DOEpatents

    Braun, Paul V. (Savoy, IL); Yu, Xindi (Urbana, IL)

    2011-01-18

    A method of making a monolithic porous structure, comprises electrodepositing a material on a template; removing the template from the material to form a monolithic porous structure comprising the material; and electropolishing the monolithic porous structure.

  13. Control of crosslinking for tailoring collagen-based scaffolds stability and mechanics

    PubMed Central

    Davidenko, N.; Schuster, C.F.; Bax, D.V.; Raynal, N.; Farndale, R.W.; Best, S.M.; Cameron, R.E.

    2015-01-01

    We provide evidence to show that the standard reactant concentrations used in tissue engineering to cross-link collagen-based scaffolds are up to 100 times higher than required for mechanical integrity in service, and stability against degradation in an aqueous environment. We demonstrate this with a detailed and systematic study by comparing scaffolds made from (a) collagen from two different suppliers, (b) gelatin (a partially denatured collagen) and (c) 50% collagen–50% gelatin mixtures. The materials were processed, using lyophilisation, to produce homogeneous, highly porous scaffolds with isotropic architectures and pore diameters ranging from 130 to 260 ?m. Scaffolds were cross-linked using a carbodiimide treatment, to establish the effect of the variations in crosslinking conditions (down to very low concentrations) on the morphology, swelling, degradation and mechanical properties of the scaffolds. Carbodiimide concentration of 11.5 mg/ml was defined as the standard (100%) and was progressively diluted down to 0.1%. It was found that 10-fold reduction in the carbodiimide content led to the significant increase (almost 4-fold) in the amount of free amine groups (primarily on collagen lysine residues) without compromising mechanics and stability in water of all resultant scaffolds. The importance of this finding is that, by reducing cross-linking, the corresponding cell-reactive carboxylate anions (collagen glutamate or aspartate residues) that are essential for integrin-mediated binding remain intact. Indeed, a 10-fold reduction in carbodiimide crosslinking resulted in near native-like cell attachment to collagen scaffolds. We have demonstrated that controlling the degree of cross-linking, and hence retaining native scaffold chemistry, offers a major step forward in the biological performance of collagen- and gelatin-based tissue engineering scaffolds. Statement of Significance This work developed collagen and gelatine-based scaffolds with structural, material and biological properties suitable for use in myocardial tissue regeneration. The novelty and significance of this research consist in elucidating the effect of the composition, origin of collagen and crosslinking concentration on the scaffold physical and cell-binding characteristics. We demonstrate that the standard carbodiimide concentrations used to crosslink collagenous scaffolds are up to 100 times higher than required for mechanical integrity in service, and stability against dissolution. The importance of this finding is that, by reducing crosslinking, the corresponding cell-reactive carboxylate anions (essential for integrin-mediated binding) remain intact and the native scaffold chemistry is retained. This offers a major step forward in the biological performance of tissue engineered scaffolds. PMID:26213371

  14. Evaluation of mechanical property and bioactivity of nano-bioglass 45S5 scaffold coated with poly-3-hydroxybutyrate.

    PubMed

    Montazeri, Mahbobeh; Karbasi, Saeed; Foroughi, Mohammad Reza; Monshi, Ahmad; Ebrahimi-Kahrizsangi, Reza

    2015-02-01

    One of the major challenges facing researchers of tissue engineering is scaffold design with desirable physical and mechanical properties for growth and proliferation of cells and tissue formation. In this research, firstly, nano-bioglass powder with grain sizes of 55-56 nm was prepared by melting method of industrial raw materials at 1,400 °C. Then the porous ceramic scaffold of bioglass with 30, 40 and 50 wt% was prepared by using the polyurethane sponge replication method. The scaffolds were coated with poly-3-hydroxybutyrate (P3HB) for 30 s and 1 min in order to increase the scaffold's mechanical properties. XRD, XRF, SEM, FE-SEM and FT-IR were used for phase and component studies, morphology, particle size and determination of functional groups, respectively. XRD and XRF results showed that the type of the produced bioglass was 45S5. The results of XRD and FT-IR showed that the best temperature to produce bioglass scaffold was 600 °C, in which Na2Ca2Si3O9 crystal is obtained. By coating the scaffolds with P3HB, a composite scaffold with optimal porosity of 80-87% in 200-600 ?m and compression strength of 0.1-0.53 MPa was obtained. According to the results of compressive strength and porosity tests, the best kind of scaffold was produced with 30 wt% of bioglass immersed for 1 min in P3HB. To evaluate the bioactivity of the scaffold, the SBF solution was used. The selected scaffold (30 wt% bioglass/6 wt% P3HB) was maintained for up to 4 weeks in this solution at an incubation temperature of 37 °C. The XRD, SEM EDXA and AAS tests were indicative of hydroxyapatite formation on the surface of bioactive scaffold. This scaffold has some potential to use in bone tissue engineering. PMID:25631260

  15. Artificial neural network for modeling the elastic modulus of electrospun polycaprolactone/gelatin scaffolds.

    PubMed

    Vatankhah, Elham; Semnani, Dariush; Prabhakaran, Molamma P; Tadayon, Mahdi; Razavi, Shahnaz; Ramakrishna, Seeram

    2014-02-01

    Scaffolds for tissue engineering (TE) require the consideration of multiple aspects, including polymeric composition and the structure and mechanical properties of the scaffolds, in order to mimic the native extracellular matrix of the tissue. Electrospun fibers are frequently utilized in TE due to their tunable physical, chemical, and mechanical properties and porosity. The mechanical properties of electrospun scaffolds made from specific polymers are highly dependent on the processing parameters, which can therefore be tuned for particular applications. Fiber diameter and orientation along with polymeric composition are the major factors that determine the elastic modulus of electrospun nano- and microfibers. Here we have developed a neural network model to investigate the simultaneous effects of composition, fiber diameter and fiber orientation of electrospun polycaprolactone/gelatin mats on the elastic modulus of the scaffolds under ambient and simulated physiological conditions. The model generated might assist bioengineers to fabricate electrospun scaffolds with defined fiber diameters, orientations and constituents, thereby replicating the mechanical properties of the native target tissue. PMID:24075888

  16. Cell colonization in degradable 3D porous matrices

    PubMed Central

    Lawrence, Benjamin J

    2008-01-01

    Cell colonization is an important in a wide variety of biological processes and applications including vascularization, wound healing, tissue engineering, stem cell differentiation and biosensors. During colonization porous 3D structures are used to support and guide the ingrowth of cells into the matrix. In this review, we summarize our understanding of various factors affecting cell colonization in three-dimensional environment. The structural, biological and degradation properties of the matrix all play key roles during colonization. Further, specific scaffold properties such as porosity, pore size, fiber thickness, topography and scaffold stiffness as well as important cell material interactions such as cell adhesion and mechanotransduction also influence colonization. PMID:19262124

  17. Integrin expression by human osteoblasts cultured on degradable polymeric materials applicable for tissue engineered bone

    E-print Network

    Lu, Helen H.

    Integrin expression by human osteoblasts cultured on degradable polymeric materials applicable was to evaluate human osteoblastic cell adherence and growth on PLAGA and PLA scaffolds by examining integrin composites. Interestingly, the integrin subunits, a2; a3; a4; a5; a6 and b1 were all expressed at higher

  18. Polymeric membrane studied using slow positron beam

    NASA Astrophysics Data System (ADS)

    Hung, Wei-Song; Lo, Chia-Hao; Cheng, Mei-Ling; Chen, Hongmin; Liu, Guang; Chakka, Lakshmi; Nanda, D.; Tung, Kuo-Lun; Huang, Shu-Hsien; Lee, Kueir-Rarn; Lai, Juin-Yih; Sun, Yi-Ming; Yu, Chang-Cheng; Zhang, Renwu; Jean, Y. C.

    2008-10-01

    A radioisotope slow positron beam has been built at the Chung Yuan Christian University in Taiwan for the research and development in membrane science and technology. Doppler broadening energy spectra and positron annihilation lifetime have been measured as a function of positron energy up to 30 keV in a polyamide membrane prepared by the interfacial polymerization between triethylenetetraamine (TETA) and trimesoyl chloride (TMC) on modified porous polyacrylonitrile (PAN) asymmetric membrane. The multilayer structures and free-volume depth profile for this asymmetric membrane system are obtained. Positron annihilation spectroscopy coupled with a slow beam could provide new information about size selectivity of transporting molecules and guidance for molecular designs in polymeric membranes.

  19. Conducting polyheterocycle composites based on porous hosts

    NASA Astrophysics Data System (ADS)

    Park, J. S.; Ruckenstein, E.

    1992-02-01

    Conducting composites based on porous substrates (cotton fiber, non-woven polypropylene mat and porous crosslinked polystyrene) have been prepared by a two step imbibition technique. First, the substrate was imbibed with a solution of monomer (pyrrole or bithiophene) in acetonitrile, followed by partial drying. Subsequently, the substrate was again imbibed, this time with an oxidant dissolved in a suitable solvent. The polymerization of the monomer inside the host in the presence of the oxidant and the doping of the polymer with the oxidant leads to the conducting composite. The highly hydrophobic and porous crosslinked polystyrene, prepared by the concentrated emulsion polymerization method, is the most efficient. The solvent employed for the oxidant plays a major role. A FeCl3-methanol system and porous crosslinked polystyrene lead to conductivities of polythiophene and polypyrrole based composites of 3.63 and 0.65 S/cm, respectively. Copper perchlorate and iron perchlorate are also suitable oxidants. The environmental and thermal stabilities of polypyrrole based composites are lower than those of polythiophene based composites. The thermal stability of polypyrrole based composites can be enhanced by including a small amount of an organic antioxidant, such as amides or substituted phenols, in the composite.

  20. Scaffolding Students' Comprehension of Text

    ERIC Educational Resources Information Center

    Clark, Kathleen F.; Graves, Michael F.

    2005-01-01

    In this article, the authors explore the concept of instructional scaffolding as it applies to facilitating students' reading comprehension. They argue that scaffolding is a highly flexible and adaptable model of instruction that supports students as they acquire both basic skills and higher order thinking processes, allows for explicit…

  1. Supercritical CO2 foamed polycaprolactone scaffolds for controlled delivery of 5-fluorouracil, nicotinamide and triflusal.

    PubMed

    Salerno, Aurelio; Saurina, Javier; Domingo, Concepción

    2015-12-30

    The manufacture of porous polycaprolactone (PCL) scaffolds containing three different drugs, namely 5-fluorouracil, nicotinamide and triflusal, was investigated in this work with the aim of obtaining bioactive systems with controlled drug delivery capabilities. The scaffolds were prepared by means of a supercritical CO2 (scCO2) foaming technique by optimizing the drug loading process. This was achieved by dissolving the drugs in organic solvents miscible with scCO2 and by mixing these drug/solvent solutions with PCL powder. The as prepared mixtures were further compressed to eliminate air bubbles and finally processed by the scCO2 foaming technique. ScCO2 saturation and foaming conditions were optimized to create the porosity within the samples and to allow for the concomitant removal of the organic solvents. Physical and chemical properties of porous scaffolds, as well as drug content and delivery profiles, were studied by HPLC. The results of this study demonstrated that the composition of the starting PCL/drug/solvent mixtures affected polymer crystallization, scaffold morphology and pore structure features. Furthermore, it was found that drug loading efficiency depended on both initial solution composition and drug solubility in scCO2. Nevertheless, in the case of highly scCO2-soluble drugs, such as triflusal, loading efficiency was improved by adding a proper amount of free drug inside of the pressure vessel. The drug delivery study indicated that release profiles depended mainly upon scaffolds composition and pore structure features. PMID:26570986

  2. Biocompatibility and compressive properties of Ti-6Al-4V scaffolds having Mg element.

    PubMed

    Kalantari, Seyed Mohammad; Arabi, Hossein; Mirdamadi, Shamsodin; Mirsalehi, Seyed Ali

    2015-08-01

    Porous scaffolds of Ti-6Al-4V were produced by mixing of this alloy with different amount of magnesium (Mg) powders. The mixtures were compacted in steel die by applying uniaxial pressure of 500 MPa before sintering the compacts in sealed quartz tubes at 900 °C for 2 h. Employing Archimedes? principle and Image Tool software, the total and open volume percentages of porosities within the scaffolds were found to be in the range of 47-64% and 41-47%, respectively. XRD results of titanium before and after sintering showed that no contamination, neither oxides nor nitrides formed during processes. Compressive properties of the scaffolds were studied using an Instron machine. The observed compressive strength and Young?s module of the scaffolds were in the range of 72-132 MPa, and 37-47 GPa, respectively. Cell attachment and proliferation rate of MG-63 on porous samples were investigated. The results showed that proliferation rate increased with increasing Mg content. However no clear differences were observed between samples regarding cell attachment, so that bridges were observed in all cell gaps within the scaffolds. PMID:25955560

  3. Emulsion templated scaffolds with tunable mechanical properties for bone tissue engineering.

    PubMed

    Owen, Robert; Sherborne, Colin; Paterson, Thomas; Green, Nicola H; Reilly, Gwendolen C; Claeyssens, Frederik

    2016-02-01

    Polymerised High Internal Phase Emulsions (PolyHIPEs) are manufactured via emulsion templating and exhibit a highly interconnected microporosity. These materials are commonly used as thin membranes for 3D cell culture. This study uses emulsion templating in combination with microstereolithography to fabricate PolyHIPE scaffolds with a tightly controlled and reproducible architecture. This combination of methods produces hierarchical structures, where the microstructural properties can be independently controlled from the scaffold macrostructure. PolyHIPEs were fabricated with varying ratios of two acrylate monomers (2-ethylhexyl acrylate (EHA) and isobornyl acrylate (IBOA)) and varying nominal porosity to tune mechanical properties. Young's modulus, ultimate tensile stress (UTS) and elongation at failure were determined for twenty EHA/IBOA compositions. Moduli ranged from 63.01±9.13 to 0.36±0.04MPa, UTS from 2.03±0.33 to 0.11±0.01MPa and failure strain from 21.86±2.87% to 2.60±0.61%. Selected compositions were fabricated into macro-porous woodpile structures, plasma treated with air or acrylic acid and seeded with human embryonic stem-cell derived mesenchymal progenitor cells (hES-MPs). Confocal and two-photon microscopy confirmed cell proliferation and penetration into the micro- and macro-porous architecture. The scaffolds supported osteogenic differentiation of mesenchymal cells and interestingly, the stiffest IBOA-based scaffolds that were plasma treated with acrylic acid promoted osteogenesis more strongly than the other scaffolds. PMID:26458114

  4. Polymeric Materials for Tissue Engineering of Arterial Substitutes