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Sample records for biocompatible gecko-inspired tissue

  1. Gecko inspired carbon nanotube based thermal gap pads

    NASA Astrophysics Data System (ADS)

    Sethi, Sunny; Dhinojwala, Ali

    2012-02-01

    Thermal management has become a critical factor in designing the next generation of microprocessors. The bottleneck in design of material for efficient heat transfer from electronic units to heat sinks is to enhance heat flow across interface between two dissimilar, rough surfaces. Carbon nanotubes (CNT) have been shown to be promising candidates for thermal transport. However, the heat transport across the interface continues to be a challenging hurdle. In the current work we designed free standing thermal pads based on gecko-inspired carbon nanotube adhesives. The pads were made of metallic carbon nanotubes and the structure was designed such that it would allow large area of intimate contact. We showed that these adhesive pads can be used as electrical and thermal interconnects.

  2. Gecko-Inspired, Controlled Adhesion and Its Applications

    NASA Astrophysics Data System (ADS)

    Menguc, Yigit

    This thesis work is primarily concerned with taking inspiration from the principles of gecko-adhesion in order to control the attachment of synthetic structured adhesives. We present gecko-inspired angled elastomer micropillars with flat or round tip endings as compliant pick-and-place micromanipulators. The pillars are 35 mum in diameter, 90 mum tall, and angled at an inclination of 20°. By gently pressing the tip of a pillar to a part, the pillar adheres to it through intermolecular forces. Next, by retracting quickly, the part is picked from a given donor substrate. During transferring, the adhesion between the pillar and the part is high enough to withstand disturbances due to external forces or the weight of the part. During release of the part onto a receiver substrate, the contact area of the pillar to the part is drastically reduced by controlled vertical or shear displacement, which results in reduced adhesive forces. The maximum repeatable ratio of pick-to-release adhesive forces was measured as 39 to 1. We find that a flat tip shape and shear displacement control provide a higher pick-to-release adhesion ratio than a round tip and vertical displacement control, respectively. We present a model of forces to serve as a framework for the operation of this micromanipulator. Finally, demonstrations of pick-and-place manipulation of mum-scale silicon microplatelets and a cm-scale glass cover slip serve as proofs of concept. The compliant polymer micropillars are safe for use with fragile parts, and, due to exploiting intermolecular forces, could be effective on most materials and in air, vacuum, and liquid environments. We present a study of the self-cleaning and contamination resistance phenomena of synthetic gecko-inspired adhesives made from elastomeric polyurethane. The phenomenon of self-cleaning makes the adhesive foot of the gecko robust against dirt, and makes it effectively sticky throughout the lifetime of the material (within the molting cycles

  3. Gecko-Inspired, Controlled Adhesion and Its Applications

    NASA Astrophysics Data System (ADS)

    Menguc, Yigit

    This thesis work is primarily concerned with taking inspiration from the principles of gecko-adhesion in order to control the attachment of synthetic structured adhesives. We present gecko-inspired angled elastomer micropillars with flat or round tip endings as compliant pick-and-place micromanipulators. The pillars are 35 mum in diameter, 90 mum tall, and angled at an inclination of 20°. By gently pressing the tip of a pillar to a part, the pillar adheres to it through intermolecular forces. Next, by retracting quickly, the part is picked from a given donor substrate. During transferring, the adhesion between the pillar and the part is high enough to withstand disturbances due to external forces or the weight of the part. During release of the part onto a receiver substrate, the contact area of the pillar to the part is drastically reduced by controlled vertical or shear displacement, which results in reduced adhesive forces. The maximum repeatable ratio of pick-to-release adhesive forces was measured as 39 to 1. We find that a flat tip shape and shear displacement control provide a higher pick-to-release adhesion ratio than a round tip and vertical displacement control, respectively. We present a model of forces to serve as a framework for the operation of this micromanipulator. Finally, demonstrations of pick-and-place manipulation of mum-scale silicon microplatelets and a cm-scale glass cover slip serve as proofs of concept. The compliant polymer micropillars are safe for use with fragile parts, and, due to exploiting intermolecular forces, could be effective on most materials and in air, vacuum, and liquid environments. We present a study of the self-cleaning and contamination resistance phenomena of synthetic gecko-inspired adhesives made from elastomeric polyurethane. The phenomenon of self-cleaning makes the adhesive foot of the gecko robust against dirt, and makes it effectively sticky throughout the lifetime of the material (within the molting cycles

  4. Human climbing with efficiently scaled gecko-inspired dry adhesives

    PubMed Central

    Hawkes, Elliot W.; Eason, Eric V.; Christensen, David L.; Cutkosky, Mark R.

    2015-01-01

    Since the discovery of the mechanism of adhesion in geckos, many synthetic dry adhesives have been developed with desirable gecko-like properties such as reusability, directionality, self-cleaning ability, rough surface adhesion and high adhesive stress. However, fully exploiting these adhesives in practical applications at different length scales requires efficient scaling (i.e. with little loss in adhesion as area grows). Just as natural gecko adhesives have been used as a benchmark for synthetic materials, so can gecko adhesion systems provide a baseline for scaling efficiency. In the tokay gecko (Gekko gecko), a scaling power law has been reported relating the maximum shear stress σmax to the area A: σmax ∝ A−1/4. We present a mechanical concept which improves upon the gecko's non-uniform load-sharing and results in a nearly even load distribution over multiple patches of gecko-inspired adhesive. We created a synthetic adhesion system incorporating this concept which shows efficient scaling across four orders of magnitude of area, yielding an improved scaling power law: σmax ∝ A−1/50. Furthermore, we found that the synthetic adhesion system does not fail catastrophically when a simulated failure is induced on a portion of the adhesive. In a practical demonstration, the synthetic adhesion system enabled a 70 kg human to climb vertical glass with 140 cm2 of adhesive per hand. PMID:25411404

  5. A microfabricated gecko-inspired controllable and reusable dry adhesive

    NASA Astrophysics Data System (ADS)

    Chary, Sathya; Tamelier, John; Turner, Kimberly

    2013-02-01

    Geckos utilize a robust reversible adhesive to repeatedly attach and detach from a variety of vertical and inverted surfaces, using structurally anisotropic micro- and nano-scale fibrillar structures. These fibers, when suitably articulated, are able to control the real area of contact and thereby generate high-to-low van der Waals forces. Key characteristics of the natural system include highly anisotropic adhesion and shear forces for controllable attachment, a high adhesion to initial preload force ratio (μ‧) of 8-16, lack of inter-fiber self-adhesion, and operation over more than 30 000 cycles without loss of adhesion performance. A highly reusable synthetic adhesive has been developed using tilted polydimethylsiloxane (PDMS) half-cylinder micron-scale fibers, retaining up to 77% of the initial value over 10 000 repeated test cycles against a flat glass puck. In comparison with other gecko-inspired adhesives tested over 10 000 cycles or more thus far, this paper reports the highest value of μ‧, along with a large shear force of ˜78 kPa, approaching the 88-226 kPa range of gecko toes. The anisotropic adhesion forces are close to theoretical estimates from the Kendall peel model, quantitatively showing how lateral shearing articulation in a manner similar to the gecko may be used to obtain adhesion anisotropy with synthetic fibers using a combination of tilt angle and anisotropic fiber geometry.

  6. Fabrication and Characterization of Gecko-inspired Fibrillar Adhesive

    NASA Astrophysics Data System (ADS)

    Kim, Yongkwan

    Over the last decade, geckos' remarkable ability to stick to and climb surfaces found in nature has motivated a wide range of scientific interest in engineering gecko-mimetic surface for various adhesive and high friction applications. The high adhesion and friction of its pads have been attributed to a complex array of hairy structures, which maximize surface area for van der Waals interaction between the toes and the counter-surface. While advances in micro- and nanolithography technique have allowed fabrication of increasingly sophisticated gecko mimetic surfaces, it remains a challenge to produce an adhesive as robust as that of the natural gecko pads. In order to rationally design gecko adhesives, understanding the contact behavior of fibrillar interface is critical. The first chapter of the dissertation introduces gecko adhesion and its potential applications, followed by a brief survey of gecko-inspired adhesives. Challenges that limit the performance of the current adhesives are presented. In particular, it is pointed out that almost all testing of gecko adhesives have been on clean, smooth glass, which is ideal for adhesion due to high surface energy and low roughness. Surfaces in application are more difficult to stick to, so the understanding of failure modes in low energy and rough surfaces is important. The second chapter presents a fabrication method for thermoplastic gecko adhesive to be used for a detailed study of fibrillar interfaces. Low-density polyethylene nanofibers are replicated from a silicon nanowire array fabricated by colloidal lithography and metal-catalyzed chemical etching. This process yields a highly ordered array of nanofibers over a large area with control over fiber diameter, length, and number density. The high yield and consistency of the process make it ideal for a systematic study on factors that affect adhesion and friction of gecko adhesives. The following three chapters examine parameters that affect macroscale friction of

  7. Adhesive behaviour of gecko-inspired nanofibrillar arrays: combination of experiments and finite element modelling

    NASA Astrophysics Data System (ADS)

    Wang, Zheng-zhi; Xu, Yun; Gu, Ping

    2012-04-01

    A polypropylene nanofibrillar array was successfully fabricated by template-assisted nanofabrication strategy. Adhesion properties of this gecko-inspired structure were studied through two parallel and independent approaches: experiments and finite element simulations. Experimental results show relatively good normal adhesion, but accompanied by high preloads. The interfacial adhesion was modelled by effective spring elements with piecewise-linear constitution. The effective elasticity of the fibre-array system was originally calculated from our measured elasticity of single nanowire. Comparisons of the experimental and simulative results reveal quantitative agreement except for some explainable deviations, which suggests the potential applicability of the present models and applied theories.

  8. Staying sticky: contact self-cleaning of gecko-inspired adhesives

    PubMed Central

    Mengüç, Yiğit; Röhrig, Michael; Abusomwan, Uyiosa; Hölscher, Hendrik; Sitti, Metin

    2014-01-01

    The exceptionally adhesive foot of the gecko remains clean in dirty environments by shedding contaminants with each step. Synthetic gecko-inspired adhesives have achieved similar attachment strengths to the gecko on smooth surfaces, but the process of contact self-cleaning has yet to be effectively demonstrated. Here, we present the first gecko-inspired adhesive that has matched both the attachment strength and the contact self-cleaning performance of the gecko's foot on a smooth surface. Contact self-cleaning experiments were performed with three different sizes of mushroom-shaped elastomer microfibres and five different sizes of spherical silica contaminants. Using a load–drag–unload dry contact cleaning process similar to the loads acting on the gecko foot during locomotion, our fully contaminated synthetic gecko adhesives could recover lost adhesion at a rate comparable to that of the gecko. We observed that the relative size of contaminants to the characteristic size of the microfibres in the synthetic adhesive strongly determined how and to what degree the adhesive recovered from contamination. Our approximate model and experimental results show that the dominant mechanism of contact self-cleaning is particle rolling during the drag process. Embedding of particles between adjacent fibres was observed for particles with diameter smaller than the fibre tips, and further studied as a temporary cleaning mechanism. By incorporating contact self-cleaning capabilities, real-world applications of synthetic gecko adhesives, such as reusable tapes, clothing closures and medical adhesives, would become feasible. PMID:24554579

  9. Mechanics of load-drag-unload contact cleaning of gecko-inspired fibrillar adhesives.

    PubMed

    Abusomwan, Uyiosa A; Sitti, Metin

    2014-10-14

    Contact self-cleaning of gecko-inspired synthetic adhesives with mushroom-shaped tips has been demonstrated recently using load-drag-unload cleaning procedures similar to that of the natural animal. However, the underlying mechanics of contact cleaning has yet to be fully understood. In this work, we present a detailed experiment of contact self-cleaning that shows that rolling is the dominant mechanism of cleaning for spherical microparticle contaminants, during the load-drag-unload procedure. We also study the effect of dragging rate and normal load on the particle rolling friction. A model of spherical particle rolling on an elastomer fibrillar adhesive interface is developed and agrees well with the experimental results. This study takes us closer to determining design parameters for achieving self-cleaning fibrillar adhesives. PMID:25244526

  10. Shear adhesion strength of thermoplastic gecko-inspired synthetic adhesive exceeds material limits.

    PubMed

    Gillies, Andrew G; Fearing, Ronald S

    2011-09-20

    Natural gecko array wearless dynamic friction has recently been reported for 30,000 cycles on a smooth substrate. Following these findings, stiff polymer gecko-inspired synthetic adhesives have been proposed for high-cycle applications such as robot feet. Here we examine the behavior of high-density polyethylene (HDPE) and polypropylene (PP) microfiber arrays during repeated cycles of engagement on a glass surface, with a normal preload of less than 40 kPa. We find that fiber arrays maintained 54% of the original shear stress of 300 kPa after 10,000 cycles, despite showing a marked plastic deformation of fiber tips. This deformation could be due to shear-induced plastic creep of the fiber tips from high adhesion forces, adhesive wear, or thermal effects. We hypothesize that a fundamental material limit has been reached for these fiber arrays and that future gecko synthetic adhesive designs must take into account the high adhesive forces generated to avoid damage. Although the synthetic material and natural gecko arrays have a similar elastic modulus, the synthetic material does not show the same wear-free dynamic friction as the gecko. PMID:21848321

  11. Importance of loading and unloading procedures for gecko-inspired controllable adhesives.

    PubMed

    Tamelier, John; Chary, Sathya; Turner, Kimberly L

    2013-08-27

    The importance of loading and unloading procedures has been shown in a variety of different methods for biological dry adhesives, such as the fibers on the feet of the Tokay gecko, but biomimetic dry adhesives have yet to be explored in a similar manner. To date, little work has systematically varied multiple parameters to discern the influence of the testing procedure, and the effect of the approach angle remains uncertain. In this study, a synthetic adhesive is moved in 13 individual approach and retraction angles relative to a flat substrate as well as 9 different shear lengths to discern how loading and unloading procedures influence the preload, adhesion, and shear/friction forces supported. The synthetic adhesive, composed of vertical 10 μm diameter semicircular poly(dimethylsiloxane) fibers, is tested against a 4 mm diameter flat glass puck on a home-built microtribometer using both vertical approach and retraction tests and angled approach and retraction tests. The results show that near maximum adhesion and friction can be obtained for most approach and retraction angles, provided that a sufficient shear length is performed. The results also show that the reaction forces during adhesive placement can be significantly reduced by using specific approach angles, resulting for the vertical fibers in a 38-fold increase in the ratio of adhesion force to preload force, μ', when compared to that when using a vertical approach. These results can be of use to those currently researching gecko-inspired adhesives when designing their testing procedures and control algorithms for climbing and perching robots. PMID:23875720

  12. Reverse adhesion of a gecko-inspired synthetic adhesive switched by an ion-exchange polymer-metal composite actuator.

    PubMed

    Guo, Dong-Jie; Liu, Rui; Cheng, Yu; Zhang, Hao; Zhou, Li-Ming; Fang, Shao-Ming; Elliott, Winston Howard; Tan, Wei

    2015-03-11

    Inspired by how geckos abduct, rotate, and adduct their setal foot toes to adhere to different surfaces, we have developed an artificial muscle material called ion-exchange polymer-metal composite (IPMC), which, as a synthetic adhesive, is capable of changing its adhesion properties. The synthetic adhesive was cast from a Si template through a sticky colloid precursor of poly(methylvinylsiloxane) (PMVS). The PMVS array of setal micropillars had a high density of pillars (3.8 × 10(3) pillars/mm(2)) with a mean diameter of 3 μm and a pore thickness of 10 μm. A graphene oxide monolayer containing Ag globular nanoparticles (GO/Ag NPs) with diameters of 5-30 nm was fabricated and doped in an ion-exchanging Nafion membrane to improve its carrier transfer, water-saving, and ion-exchange capabilities, which thus enhanced the electromechanical response of IPMC. After being attached to PMVS micropillars, IPMC was actuated by square wave inputs at 1.0, 1.5, or 2.0 V to bend back and forth, driving the micropillars to actively grip or release the surface. To determine the adhesion of the micropillars, the normal adsorption and desorption forces were measured as the IPMC drives the setal micropillars to grip and release, respectively. Adhesion results demonstrated that the normal adsorption forces were 5.54-, 14.20-, and 23.13-fold higher than the normal desorption forces under 1.0, 1.5, or 2.0 V, respectively. In addition, shear adhesion or friction increased by 98, 219, and 245%, respectively. Our new technique provides advanced design strategies for reversible gecko-inspired synthetic adhesives, which might be used for spiderman-like wall-climbing devices with unprecedented performance. PMID:25676143

  13. Design of gecko-inspired fibrillar surfaces with strong attachment and easy-removal properties: a numerical analysis of peel-zone.

    PubMed

    Zhou, Ming; Pesika, Noshir; Zeng, Hongbo; Wan, Jin; Zhang, Xiangjun; Meng, Yonggang; Wen, Shizhu; Tian, Yu

    2012-10-01

    Despite successful fabrication of gecko-inspired fibrillar surfaces with strong adhesion forces, how to achieve an easy-removal property becomes a major concern that may restrict the wide applications of these bio-inspired surfaces. Research on how geckos detach rapidly has inspired the design of novel adhesive surfaces with strong and reversible adhesion capabilities, which relies on further fundamental understanding of the peeling mechanisms. Recent studies showed that the peel-zone plays an important role in the peeling off of adhesive tapes or fibrillar surfaces. In this study, a numerical method was developed to evaluate peel-zone deformation and the resulting mechanical behaviour due to the deformations of fibrillar surfaces detaching from a smooth rigid substrate. The effect of the geometrical parameters of pillars and the stiffness of backing layer on the peel-zone and peel strength, and the strong attachment and easy-removal properties have been analysed to establish a design map for bio-inspired fibrillar surfaces, which shows that the optimized strong attachment and easy-removal properties can vary by over three orders of magnitude. The adhesion and peeling design map established provides new insights into the design and development of novel gecko-inspired fibrillar surfaces. PMID:22572030

  14. Biocompatible magnetic core-shell nanocomposites for engineered magnetic tissues

    NASA Astrophysics Data System (ADS)

    Rodriguez-Arco, Laura; Rodriguez, Ismael A.; Carriel, Victor; Bonhome-Espinosa, Ana B.; Campos, Fernando; Kuzhir, Pavel; Duran, Juan D. G.; Lopez-Lopez, Modesto T.

    2016-04-01

    The inclusion of magnetic nanoparticles into biopolymer matrixes enables the preparation of magnetic field-responsive engineered tissues. Here we describe a synthetic route to prepare biocompatible core-shell nanostructures consisting of a polymeric core and a magnetic shell, which are used for this purpose. We show that using a core-shell architecture is doubly advantageous. First, gravitational settling for core-shell nanocomposites is slower because of the reduction of the composite average density connected to the light polymer core. Second, the magnetic response of core-shell nanocomposites can be tuned by changing the thickness of the magnetic layer. The incorporation of the composites into biopolymer hydrogels containing cells results in magnetic field-responsive engineered tissues whose mechanical properties can be controlled by external magnetic forces. Indeed, we obtain a significant increase of the viscoelastic moduli of the engineered tissues when exposed to an external magnetic field. Because the composites are functionalized with polyethylene glycol, the prepared bio-artificial tissue-like constructs also display excellent ex vivo cell viability and proliferation. When implanted in vivo, the engineered tissues show good biocompatibility and outstanding interaction with the host tissue. Actually, they only cause a localized transitory inflammatory reaction at the implantation site, without any effect on other organs. Altogether, our results suggest that the inclusion of magnetic core-shell nanocomposites into biomaterials would enable tissue engineering of artificial substitutes whose mechanical properties could be tuned to match those of the potential target tissue. In a wider perspective, the good biocompatibility and magnetic behavior of the composites could be beneficial for many other applications.The inclusion of magnetic nanoparticles into biopolymer matrixes enables the preparation of magnetic field-responsive engineered tissues. Here we

  15. Biocompatible magnetic core-shell nanocomposites for engineered magnetic tissues.

    PubMed

    Rodriguez-Arco, Laura; Rodriguez, Ismael A; Carriel, Victor; Bonhome-Espinosa, Ana B; Campos, Fernando; Kuzhir, Pavel; Duran, Juan D G; Lopez-Lopez, Modesto T

    2016-04-14

    The inclusion of magnetic nanoparticles into biopolymer matrixes enables the preparation of magnetic field-responsive engineered tissues. Here we describe a synthetic route to prepare biocompatible core-shell nanostructures consisting of a polymeric core and a magnetic shell, which are used for this purpose. We show that using a core-shell architecture is doubly advantageous. First, gravitational settling for core-shell nanocomposites is slower because of the reduction of the composite average density connected to the light polymer core. Second, the magnetic response of core-shell nanocomposites can be tuned by changing the thickness of the magnetic layer. The incorporation of the composites into biopolymer hydrogels containing cells results in magnetic field-responsive engineered tissues whose mechanical properties can be controlled by external magnetic forces. Indeed, we obtain a significant increase of the viscoelastic moduli of the engineered tissues when exposed to an external magnetic field. Because the composites are functionalized with polyethylene glycol, the prepared bio-artificial tissue-like constructs also display excellent ex vivo cell viability and proliferation. When implanted in vivo, the engineered tissues show good biocompatibility and outstanding interaction with the host tissue. Actually, they only cause a localized transitory inflammatory reaction at the implantation site, without any effect on other organs. Altogether, our results suggest that the inclusion of magnetic core-shell nanocomposites into biomaterials would enable tissue engineering of artificial substitutes whose mechanical properties could be tuned to match those of the potential target tissue. In a wider perspective, the good biocompatibility and magnetic behavior of the composites could be beneficial for many other applications. PMID:27029891

  16. Instantly switchable adhesion of bridged fibrillar adhesive via gecko-inspired detachment mechanism and its application to a transportation system

    NASA Astrophysics Data System (ADS)

    Bae, Won-Gyu; Kim, Doogon; Suh, Kahp-Yang

    2013-11-01

    climbing behaviour of gecko lizards. The adhesive shows strong normal attachment (~30 N cm-2) as well as easy and fast detachment within 0.5 s without involving complex dynamic mechanisms or specific stimulus-responsive materials. The fabrication of the bridged micropillars consists of replica moulding of polydimethylsiloxane (PDMS) micropillars, transfer of the PDMS precursor to the heads of the micropillars, and inverse placement on an inert Teflon-coated surface. Owing to the spontaneous interconnections of low viscosity PDMS precursor, bridged micropillars with a uniform capping nanomembrane (~800 nm thickness) are formed over a large area. Interestingly, macroscopic adhesion in the normal direction can be immediately switched between on and off states by changing the two detachment modes of pulling and peeling, respectively. To prove the potential of the fibrillar adhesive for practical use, an automated transportation system is demonstrated for lifting and releasing a mass of stacked glass slides over 1000 cycles of attachment and detachment. Electronic supplementary information (ESI) available: Photograph of a custom-built adhesion measurement system, video snapshots showing the switchable adhesion via gecko-inspired detachment mechanism, schematic of fabricating a master mould, and a SEM image showing the thickness of the nanomembrane. See DOI: 10.1039/c3nr02008h

  17. Building Biocompatible Hydrogels for Tissue Engineering of the Brain and Spinal Cord

    PubMed Central

    Aurand, Emily R.; Wagner, Jennifer; Lanning, Craig; Bjugstad, Kimberly B.

    2012-01-01

    Tissue engineering strategies employing biomaterials have made great progress in the last few decades. However, the tissues of the brain and spinal cord pose unique challenges due to a separate immune system and their nature as soft tissue. Because of this, neural tissue engineering for the brain and spinal cord may require re-establishing biocompatibility and functionality of biomaterials that have previously been successful for tissue engineering in the body. The goal of this review is to briefly describe the distinctive properties of the central nervous system, specifically the neuroimmune response, and to describe the factors which contribute to building polymer hydrogels compatible with this tissue. These factors include polymer chemistry, polymerization and degradation, and the physical and mechanical properties of the hydrogel. By understanding the necessities in making hydrogels biocompatible with tissue of the brain and spinal cord, tissue engineers can then functionalize these materials for repairing and replacing tissue in the central nervous system. PMID:24955749

  18. Biocompatibility evaluation of tissue-engineered decellularized scaffolds for biomedical application.

    PubMed

    Hussein, Kamal Hany; Park, Kyung-Mee; Kang, Kyung-Sun; Woo, Heung-Myong

    2016-10-01

    Biomaterials based on seeding of cells on decellularized scaffolds have gained increasing interest in the last few years and suggested to serve as an alternative approach to bioengineer artificial organs and tissues for transplantation. The reaction of the host toward the decellularized scaffold and transplanted cells depends on the biocompatibility of the construct. Before proceeding to the clinical application step of decellularized scaffolds, it is greatly important to apply a number of biocompatibility tests in vitro and in vivo. This review describes the different methodology involved in cytotoxicity, pathogenicity, immunogenicity and biodegradability testing for evaluating the biocompatibility of various decellularized matrices obtained from human or animals. PMID:27287176

  19. [Intravascular biocompatibility of decellularized xenogenic vascular scaffolds/PHBHHx hybrid material for cardiovascular tissue engineering].

    PubMed

    Wu, Song; Liu, Yinglong; Cui, Bin; Tang, Yue; Wang, Qiang; Qu, Xianghua; Chen, Guoqiang

    2008-04-01

    Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate, PHBHHx) has superior mechanical and biocompatibility that may enable it to meet cardiovascular tissue engineering applications. We developed hybrid materials based on decellularized xenogenic vascular scaffolds that were coated with PHBHHx to investigate the intravascular biocompatibility. The hybrid patches were implanted in the rabbit abdominal aorta (hybrid patch, n = 12). Only decellularized xenogenic vascular scaffolds were implanted without coating as control (uncoated patch, n = 12). The patches were explanted and examined histologically, and biochemically at 1, 4 and 12 weeks after the surgery. The hybrid patches maintained original shapes, covered by confluent layer of cells and had less calcification than uncoated control. The results indicated that PHBHHx coating reduced calcification, promoted the repopulation of hybrid patch with recipients cells. In conclusion, PHBHHx showed remarkable intravascular biocompatibility and would benefit endothelization which would be a useful candidate for lumen of cardiovascular tissue engineering. PMID:18616171

  20. Utilizing acid pretreatment and electrospinning to improve biocompatibility of poly(glycolic acid) for tissue engineering.

    PubMed

    Boland, Eugene D; Telemeco, Todd A; Simpson, David G; Wnek, Gary E; Bowlin, Gary L

    2004-10-15

    Poly(glycolic acid) (PGA) has a long history as a bioresorbable polymer. Its biocompatibility is widely accepted, yet PGA is often rejected as a soft-tissue scaffold because of fibrous encapsulation. The goal of this study was to improve the soft-tissue biocompatibility of PGA by producing scaffolds composed of small-diameter fibers through electrospinning and subjecting these scaffolds to a concentrated hydrochloric acid (HCL) pretreatment. The theory is that small-diameter fibers will elicit a reduced immune response and HCl treatment will improve cellular interactions. Scaffolds were characterized in terms of fiber diameter and pore area via image-analysis software. Biocompatibility was assessed through a WST-1 cell-proliferation assay (in vitro) with the use of rat cardiac fibroblasts and rat intramuscular implantations (in vivo). Fibers produced ranged in diameter from 0.22 to 0.88 microm with pore areas from 1.84 to 13.22 microm(2). The untreated scaffold composed of 0.88-microm fibers was encapsulated in vivo and supported the lowest rates of cell proliferation. On the contrary, the acid pretreated scaffold with 0.22-microm fibers was incorporated into the surrounding tissue and exhibited proliferation rates that exceeded the control populations on tissue-culture plastic. In conclusion, this study has shown the ability to improve the biocompatibility of PGA through acid pretreatment of scaffolds comprised of submicron fiber diameters. PMID:15368238

  1. Light-guided localization within tissue using biocompatible surgical suture fiber as an optical waveguide

    NASA Astrophysics Data System (ADS)

    Choi, Woo June; Park, Kwan Seob; Lee, Byeong Ha

    2014-09-01

    In breast-conserving surgery, an optical wire is a useful surgical guiding tool to optically locate small lesions within the breast tissue. However, the use of a long silica glass fiber as the optical wire can be burdensome to patients because of its stiffness and nonbiocompatibility. We investigate the use of a biocompatible fiber for light localization in tissue. A surgical suture with a diameter of 400 μm and a few centimeters long is employed as the biocompatible optical waveguide to transport the visible laser light to the inner tissue site. Optical location is confirmed with glow ball-like red laser illumination at the tip of the suture embedded within a fresh chicken breast tissue. Effective optical power coupling to the suture is made by using a double-cladding fiber coupler. From this preliminary result, we realize practical light localization with biopolymer waveguides.

  2. Light-guided localization within tissue using biocompatible surgical suture fiber as an optical waveguide.

    PubMed

    Choi, Woo June; Park, Kwan Seob; Lee, Byeong Ha

    2014-09-01

    In breast-conserving surgery, an optical wire is a useful surgical guiding tool to optically locate small lesions within the breast tissue. However, the use of a long silica glass fiber as the optical wire can be burdensome to patients because of its stiffness and nonbiocompatibility. We investigate the use of a biocompatible fiber for light localization in tissue. A surgical suture with a diameter of 400 μm and a few centimeters long is employed as the biocompatible optical waveguide to transport the visible laser light to the inner tissue site. Optical location is confirmed with glow ball-like red laser illumination at the tip of the suture embedded within a fresh chicken breast tissue. Effective optical power coupling to the suture is made by using a double-cladding fiber coupler. From this preliminary result, we realize practical light localization with biopolymer waveguides. PMID:25202898

  3. Evaluation of the biocompatibility of resin-based root canal sealers in rat periapical tissue.

    PubMed

    Mutoh, Noriko; Satoh, Takenori; Watabe, Hirotaka; Tani-Ishii, Nobuyuki

    2013-01-01

    We evaluated the biocompatibility of resin-based root canal sealers (RCSs) in the periapical tissues of rats. Wistar rats underwent tooth replantation for reproducing the response of periapical tissue with RCSs. The resin-based Epipany SE, AH Plus Jet, the eugenol-based sealer (Canals) and a control group were employed. The upper right first molar was extracted and applied with RCSs on apices, and then the tooth was repositioned. Histological evaluation demonstrated that mild inflammation occurred in the periapical tissue with Epiphany and AH Plus Jet sealers on day 7, whereas Canals induced severe-to-moderate inflammation. The statistical analyses demonstrated that the significant differences were observed between Canals and the other groups on day 7 regarding inflammatory response. On day 14, the lesions induced by all sealers were healed and replaced predominantly by fibrous connective tissue. Our results suggest that Epiphany SE and AH Plus Jet are good biocompatible materials. PMID:23719002

  4. Biocompatibility of a calcium hydroxide-propolis experimental paste in rat subcutaneous tissue.

    PubMed

    Mori, Graziela Garrido; Rodrigues, Sindineia da Silva; Shibayama, Sheila Tieko; Pomini, Marcelo; do Amaral, Cristhiane Olivia Ferreira

    2014-01-01

    Intracanal medications are fundamental for disinfection of the root canal system and participate in periapical repair, so their biocompatibility is of utmost importance to avoid tissue damage. This study evaluated the biocompatibility of a experimental paste of calcium hydroxide and propolis in the subcutaneous tissue of rats. The study was conducted on 15 male Wistar rats. Two incisions were made on the dorsal region of each animal for introduction of 4 tubes: one tube was empty; one contained zinc oxide-eugenol cement, and the two other tubes were filled with experimental paste. After 7, 14 and 30 days, the animals were euthanized and the specimens were subjected to histotechnical preparation. The hematoxylin and eosin-stained histological sections were analyzed by light microscopy. Scores were established according to the inflammatory process and statistically compared by the Tukey test (α = 5%). The analysis of histological sections showed non-significant or mild inflammatory reaction in the connective tissue in contact with the empty tubes in all study periods while the contact of subcutaneous tissue with zinc oxide-eugenol elicited moderate or severe inflammation similarly without significant difference among the study periods. The connective tissue was moderately inflamed at 7 days when contacting the experimental paste, but the inflammatory process was non-significant or mild at 14 and 30 days. The experimental paste was biocompatible with the tissues after 14 days of subcutaneous implantation. PMID:25140713

  5. Immunologic and tissue biocompatibility of flexible/stretchable electronics and optoelectronics.

    PubMed

    Park, Gayoung; Chung, Hyun-Joong; Kim, Kwanghee; Lim, Seon Ah; Kim, Jiyoung; Kim, Yun-Soung; Liu, Yuhao; Yeo, Woon-Hong; Kim, Rak-Hwan; Kim, Stanley S; Kim, Jong-Seon; Jung, Yei Hwan; Kim, Tae-Il; Yee, Cassian; Rogers, John A; Lee, Kyung-Mi

    2014-04-01

    Recent development of flexible/stretchable integrated electronic sensors and stimulation systems has the potential to establish an important paradigm for implantable electronic devices, where shapes and mechanical properties are matched to those of biological tissues and organs. Demonstrations of tissue and immune biocompatibility are fundamental requirements for application of such kinds of electronics for long-term use in the body. Here, a comprehensive set of experiments studies biocompatibility on four representative flexible/stretchable device platforms, selected on the basis of their versatility and relevance in clinical usage. The devices include flexible silicon field effect transistors (FETs) on polyimide and stretchable silicon FETs, InGaN light-emitting diodes (LEDs), and AlInGaPAs LEDs, each on low modulus silicone substrates. Direct cytotoxicity measured by exposure of a surrogate fibroblast line and leachable toxicity by minimum essential medium extraction testing reveal that all of these devices are non-cytotoxic. In vivo immunologic and tissue biocompatibility testing in mice indicate no local inflammation or systemic immunologic responses after four weeks of subcutaneous implantation. The results show that these new classes of flexible implantable devices are suitable for introduction into clinical studies as long-term implantable electronics. PMID:23996980

  6. Tissue biocompatibility of kevlar aramid fibers and polymethylmethacrylate, composites in rabbits.

    PubMed

    Henderson, J D; Mullarky, R H; Ryan, D E

    1987-01-01

    Two groups of female NZW rabbits were implanted in the paravertebral muscles with aramid (du Pont Kevlar aramid 49) fibers and aramid-polymethylmethacrylate (PMMA) composites for 14 and 28 days. Rabbits were killed at these times periods, necropsies performed, sites scored for gross tissue response, and tissue specimens containing the implants removed for histopathological evaluation. A mild fibrous tissue reaction was observed around all implants containing aramid fiber similar to that observed around the silicone control implant. Some foreign body giant cells were also present adjacent to the fibers. An intense necrotic inflammatory reaction was present around the positive control material (PVC Y-78). The tissue response to implantation of aramid fiber and fiber-PMMA composites indicates that aramid is a biocompatible material. PMID:3558440

  7. Rapid prototyping for tissue-engineered bone scaffold by 3D printing and biocompatibility study

    PubMed Central

    He, Hui-Yu; Zhang, Jia-Yu; Mi, Xue; Hu, Yang; Gu, Xiao-Yu

    2015-01-01

    The prototyping of tissue-engineered bone scaffold (calcined goat spongy bone-biphasic ceramic composite/PVA gel) by 3D printing was performed, and the biocompatibility of the fabricated bone scaffold was studied. Pre-designed STL file was imported into the GXYZ303010-XYLE 3D printing system, and the tissue-engineered bone scaffold was fabricated by 3D printing using gel extrusion. Rabbit bone marrow stromal cells (BMSCs) were cultured in vitro and then inoculated to the sterilized bone scaffold obtained by 3D printing. The growth of rabbit BMSCs on the bone scaffold was observed under the scanning electron microscope (SEM). The effect of the tissue-engineered bone scaffold on the proliferation and differentiation of rabbit BMSCs using MTT assay. Universal testing machine was adopted to test the tensile strength of the bone scaffold. The leachate of the bone scaffold was prepared and injected into the New Zealand rabbits. Cytotoxicity test, acute toxicity test, pyrogenic test and intracutaneous stimulation test were performed to assess the biocompatibility of the bone scaffold. Bone scaffold manufactured by 3D printing had uniform pore size with the porosity of about 68.3%. The pores were well interconnected, and the bone scaffold showed excellent mechanical property. Rabbit BMSCs grew and proliferated on the surface of the bone scaffold after adherence. MTT assay indicated that the proliferation and differentiation of rabbit BMSCs on the bone scaffold did not differ significantly from that of the cells in the control. In vivo experiments proved that the bone scaffold fabricated by 3D printing had no acute toxicity, pyrogenic reaction or stimulation. Bone scaffold manufactured by 3D printing allows the rabbit BMSCs to adhere, grow and proliferate and exhibits excellent biomechanical property and high biocompatibility. 3D printing has a good application prospect in the prototyping of tissue-engineered bone scaffold. PMID:26380018

  8. Rheological, biocompatibility and osteogenesis assessment of fish collagen scaffold for bone tissue engineering.

    PubMed

    Elango, Jeevithan; Zhang, Jingyi; Bao, Bin; Palaniyandi, Krishnamoorthy; Wang, Shujun; Wenhui, Wu; Robinson, Jeya Shakila

    2016-10-01

    In the present investigation, an attempt was made to find an alternative to mammalian collagen with better osteogenesis ability. Three types of collagen scaffolds - collagen, collagen-chitosan (CCH), and collagen-hydroxyapatite (CHA) - were prepared from the cartilage of Blue shark and investigated for their physico-functional and mechanical properties in relation to biocompatibility and osteogenesis. CCH scaffold was superior with pH 4.5-4.9 and viscosity 9.7-10.9cP. Notably, addition of chitosan and HA (hydroxyapatite) improved the stiffness (11-23MPa) and degradation rate but lowered the water binding capacity and porosity of the scaffold. Interestingly, CCH scaffolds remained for 3days before complete in-vitro biodegradation. The decreased amount of viable T-cells and higher level of FAS/APO-1 were substantiated the biocompatibility properties of prepared collagen scaffolds. Osteogenesis study revealed that the addition of CH and HA in both fish and mammalian collagen scaffolds could efficiently promote osteoblast cell formation. The ALP activity was significantly high in CHA scaffold-treated osteoblast cells, which suggests an enhanced bone-healing process. Therefore, the present study concludes that the composite scaffolds prepared from fish collagen with higher stiffness, lower biodegradation rate, better biocompatible, and osteogenesis properties were suitable biomaterial for a bone tissue engineering application as an alternative to mammalian collagen scaffolds. PMID:27211297

  9. Biocompatibility and cytotoxic evaluation of drug-loaded biodegradable guided tissue regeneration membranes

    PubMed Central

    Thomas, Nebu G.; Sanil, George P.; Gopimohan, Rajmohan; Prabhakaran, Jayachandran V.; Thomas, George; Panda, Amulya K.

    2012-01-01

    Background: In periodontology, Guided Tissue Regeneration (GTR) is based on the concept of providing a space for entry of cells with regenerative potential into the wound environment to initiate the regeneration of structures lost due to periodontal disease. First generation GTR membranes were primarily non-absorbable membranes like expanded polytetrafluorethylene which required a second surgery for its removal. This led researchers to explore absorbable materials like collagen and synthetic biodegradable polymers to fabricate GTR membranes. In the present study, biodegradable Polylactic acid (PLA) is used to fabricate membranes with the potential to be used for GTR therapy. Materials and Methods: Biocompatibility of the PLA membranes were evaluated in a subcutaneous guinea pig model. Antimicrobial effect of the drug-loaded PLA membranes were assessed against a drug-resistant Staphylococcus aureus bacterial isolate. The cytocompatibility of the drug-loaded membranes were evaluated using HeLa cell lines. Results: The PLA membranes were shown to be biocompatible. The drug-loaded PLA membranes showed significant activity against the bacterial isolate. Among the drug-loaded membranes, tetracycline-loaded membrane showed minimal cellular toxicity. Conclusion: The results of this study indicate that biodegradable drug-releasing polylactide membranes have the potential to be used for periodontal regeneration. It has the necessary characteristics of a GTR membrane like biocompatibility, space maintaining ability, and tissue integration. Among the various antimicrobial agents loaded in the PLA membranes, tetracycline-loaded membranes exhibited minimal cellular toxicity against HeLa cells; at the same time showing significant activity against a pathogenic bacterium. PMID:23492817

  10. Properties and Biocompatibility of Chitosan and Silk Fibroin Blend Films for Application in Skin Tissue Engineering

    PubMed Central

    Luangbudnark, Witoo; Viyoch, Jarupa; Laupattarakasem, Wiroon; Surakunprapha, Palakorn; Laupattarakasem, Pisamai

    2012-01-01

    Chitosan/silk fibroin (CS/SF) blend films were prepared and evaluated for feasibility of using the films as biomaterial for skin tissue engineering application. Fourier transform infrared spectroscopy and differential scanning calorimetry analysis indicated chemical interaction between chitosan and fibroin. Chitosan enhanced β-sheet conformation of fibroin and resulted in shifting of thermal degradation of the films. Flexibility, swelling index, and enzyme degradation were also increased by the chitosan content of the blend films. Biocompatibility of the blend films was determined by cultivation with fibroblast cells. All films showed no cytotoxicity by XTT assay. Fibroblast cells spread on CS/SF films via dendritic extensions, and cell-cell interactions were noted. Cell proliferation on CS/SF films was also demonstrated, and their phenotype was examined by the expression of collagen type I gene. These results showed possibility of using the CS/SF films as a supporting material for further study on skin tissue engineering. PMID:22701367

  11. Hydroxyapatite-magnetite-MWCNT nanocomposite as a biocompatible multifunctional drug delivery system for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Pistone, Alessandro; Iannazzo, Daniela; Panseri, Silvia; Montesi, Monica; Tampieri, Anna; Galvagno, Signorino

    2014-10-01

    New magnetic hydroxyapatite-based nanomaterials as bone-specific systems for controlled drug delivery have been synthesized. The synthesized hydroxyapatite, HA, decorated with magnetite nanoparticles by a deposition method (HA/Fe3O4) and the nanocomposite system obtained using magnetic multi-walled carbon nanotubes (HA/MWCNT/Fe3O4) as a filler for HA have been characterized by chemical and morphological analyses, and their biological behavior was investigated. The systems have also been doped with clodronate in order to combine the effect of bone biomineralization induced by hydroxyapatite-based composites with the decrease of osteoclast formation induced by the drug. An analysis of the preosteoclastic RAW264.7 cell proliferation by MTT assay confirmed the high biocompatibility of the three systems. TRAP staining of RAW 264.7 conditioned with sRAKL to induce osteoclastogenesis, cultured in the presence of the systems doped and undoped with clodronate, showed the inhibitory effect of clodronate after we counted the MNC TRAP+cells but only in the osteoclast formation; in particular, the system HA/Fe3O4-Clo exerted a high inhibitory effect compared to the drug alone. These results demonstrate that the synthesized nanocomposites are a biocompatible magnetic drug delivery system and can represent a useful multimodal platform for applications in bone tissue engineering.

  12. Study on the optical property and biocompatibility of a tissue engineering cornea

    PubMed Central

    Zhang, Xu; Nakahara, Yukiko; Xuan, Dwight; Wu, Di; Zhao, Fang-Kun; Li, Xiao-Yan; Zhang, Jin-Song

    2012-01-01

    AIM To study the optical property and biocompatibility of a tissue engineering cornea. METHODS : The cross-linker of N-(3-Dimethylaminoropyl)-N'ethylcarbodiimide hydrochloride (EDC)/N-Hydroxysuccinimide (NHS) was mixed with Type I collagen at 10% (weight/volume). The final solution was molded to the shape of a corneal contact lens. The collagen concentrations of 10%, 12.5%, 15%, 17.5% and 20% artificial corneas were tested by UV/vis-spectroscopy for their transparency compared with normal rat cornea. 10-0 sutures were knotted on the edges of substitute to measure the corneal buttons's mechanical properties. Normal rat corneal tissue primary culture on the collagen scaffold was observed in 4 weeks. Histopathologic examinations were performed after 4 weeks of in vitro culturing. RESULTS The collagen scaffold appearance was similar to that of soft contact lens. With the increase of collagen concentration, the transparency of artificial corneal buttons was diminished, but the toughness of the scaffold was enhanced. The scaffold transparency in the 10% concentration collagen group resembled normal rat cornea. To knot and embed the scaffold under the microscope, 20% concentration collagen group was more effective during implantation than lower concentrations of collagen group. In the first 3 weeks, corneal cell proliferation was highly active. The shapes of cells that grew on the substitute had no significant difference when compared with the cells before they were moved to the scaffold. However, on the fortieth day, most cells detached from the scaffold and died. Histopathologic examination of the primary culture scaffold revealed well grown corneal cells tightly attached to the scaffold in the former culturing. CONCLUSION Collagen scaffold can be molded to the shape of soft contact corneal lens with NHS/EDC. The biological stability and biocompatibility of collagen from animal species may be used as material in preparing to engineer artificial corneal scaffold. PMID

  13. Tissue Reaction and Biocompatibility of Implanted Mineral Trioxide Aggregate with Silver Nanoparticles in a Rat Model

    PubMed Central

    Zand, Vahid; Lotfi, Mehrdad; Aghbali, Amirala; Mesgariabbasi, Mehran; Janani, Maryam; Mokhtari, Hadi; Tehranchi, Pardis; Pakdel, Seyyed Mahdi Vahid

    2016-01-01

    Introduction: Biocompatibility and antimicrobial activity of endodontic materials are of utmost importance. Considering the extensive applications of mineral trioxide aggregate (MTA) in dentistry and antimicrobial properties of silver nanoparticles, this study aimed to evaluate the subcutaneous inflammatory reaction of rat connective tissues to white MTA with and without nanosilver (NS) particles. Methods and Materials: Polyethylene tubes (1.1×8 mm) containing experimental materials (MTA and MTA+NS and empty control tubes) were implanted in subcutaneous tissues of seventy-five male rats. Animals were divided into five groups (n=15) according to the time of evaluation: group 1; after 7 days, group 2; after 15 days, group 3; after 30 days, group 4; after 60 days and group 5; after 90 days. The inflammatory reaction was graded and data was analyzed using the Kruskal-Wallis and Mann-Whitney U tests. Statistical significance was defined at 0.05. Results: Comparison of cumulative inflammatory reaction at all intervals revealed that the mean grade of inflammatory reaction to MTA, MTA+NS and control samples were 3, 2 and 2, respectively. According to the Mann-Whitney analysis there were no significant differences between MTA+NS and MTA (P=0.42). Conclusion: Incorporation of 1% nanosilver to MTA does not affect the inflammatory reaction of subcutaneous tissue in rat models. PMID:26843871

  14. 1,4-Dioxane enhances properties and biocompatibility of polyanionic collagen for tissue engineering applications.

    PubMed

    Forti, Fabio L; Bet, Marcos R; Goissis, Gilberto; Plepis, Ana M G

    2011-08-01

    Polyanionic collagen obtained from bovine pericardial tissue submitted to alkaline hydrolysis is an acellular matrix with strong potential in tissue engineering. However, increasing the carboxyl content reduces fibril formation and thermal stability compared to the native tissues. In the present work, we propose a chemical protocol based on the association of alkaline hydrolysis with 1,4-dioxane treatment to either attenuate or revert the drastic structural modifications promoted by alkaline treatments. For the characterization of the polyanionic membranes treated with 1,4-dioxane, we found that (1) scanning electron microscopy (SEM) shows a stronger reorientation and aggregation of collagen microfibrils; (2) histological evaluation reveals recovering of the alignment of collagen fibers and reassociation with elastic fibers; (3) differential scanning calorimetry (DSC) shows an increase in thermal stability; and (4) in biocompatibility assays there is a normal attachment, morphology and proliferation associated with high survival of the mouse fibroblast cell line NIH3T3 in reconstituted membranes, which behave as native membranes. Our conclusions reinforce the ability of 1,4-dioxane to enhance the properties of negatively charged polyanionic collagen associated with its potential use as biomaterials for grafting, cationic drug- or cell-delivery systems and for the coating of cardiovascular devices. PMID:21643966

  15. Tautomerizable β-ketonitrile copolymers for bone tissue engineering: Studies of biocompatibility and cytotoxicity.

    PubMed

    Lastra, M Laura; Molinuevo, M Silvina; Giussi, Juan M; Allegretti, Patricia E; Blaszczyk-Lezak, Iwona; Mijangos, Carmen; Cortizo, M Susana

    2015-06-01

    β-Ketonitrile tautomeric copolymers have demonstrated tunable hydrophilicity/hydrophobicity properties according to surrounding environment, and mechanical properties similar to those of human bone tissue. Both characteristic properties make them promising candidates as biomaterials for bone tissue engineering. Based on this knowledge we have designed two scaffolds based on β-ketonitrile tautomeric copolymers which differ in chemical composition and surface morphology. Two of them were nanostructured, using an anodized aluminum oxide (AAO) template, and the other two obtained by solvent casting methodology. They were used to evaluate the effect of the composition and their structural modifications on the biocompatibility, cytotoxicity and degradation properties. Our results showed that the nanostructured scaffolds exhibited higher degradation rate by macrophages than casted scaffolds (6 and 2.5% of degradation for nanostructured and casted scaffolds, respectively), a degradation rate compatible with bone regeneration times. We also demonstrated that the β-ketonitrile tautomeric based scaffolds supported osteoblastic cell proliferation and differentiation without cytotoxic effects, suggesting that these biomaterials could be useful in the bone tissue engineering field. PMID:25842133

  16. Ultrashort pulse laser processing of hard tissue, dental restoration materials, and biocompatibles

    NASA Astrophysics Data System (ADS)

    Yousif, A.; Strassl, M.; Beer, F.; Verhagen, L.; Wittschier, M.; Wintner, E.

    2007-07-01

    During the last few years, ultra-short laser pulses have proven their potential for application in medical tissue treatment in many ways. In hard tissue ablation, their aptitude for material ablation with negligible collateral damage provides many advantages. Especially teeth representing an anatomically and physiologically very special region with less blood circulation and lower healing rates than other tissues require most careful treatment. Hence, overheating of the pulp and induction of microcracks are some of the most problematic issues in dental preparation. Up till now it was shown by many authors that the application of picosecond or femtosecond pulses allows to perform ablation with very low damaging potential also fitting to the physiological requirements indicated. Beside the short interaction time with the irradiated matter, scanning of the ultra-short pulse trains turned out to be crucial for ablating cavities of the required quality. One main reason for this can be seen in the fact that during scanning the time period between two subsequent pulses incident on the same spot is so much extended that no heat accumulation effects occur and each pulse can be treated as a first one with respect to its local impact. Extension of this advantageous technique to biocompatible materials, i.e. in this case dental restoration materials and titanium plasma-sprayed implants, is just a matter of consequence. Recently published results on composites fit well with earlier data on dental hard tissue. In case of plaque which has to be removed from implants, it turns out that removal of at least the calcified version is harder than tissue removal. Therefore, besides ultra-short lasers, also Diode and Neodymium lasers, in cw and pulsed modes, have been studied with respect to plaque removal and sterilization. The temperature increase during laser exposure has been experimentally evaluated in parallel.

  17. Adult stem cells and biocompatible scaffolds as smart drug delivery tools for cardiac tissue repair.

    PubMed

    Pagliari, Stefania; Romanazzo, Sara; Mosqueira, Diogo; Pinto-do-Ó, Perpetua; Aoyagi, Takao; Forte, Giancarlo

    2013-01-01

    The contribution of adult stem cells to cardiac repair is mostly ascribed to an indirect paracrine effect, rather than to their actual engraftment and differentiation into new contractile and vascular cells. This effect consists in a direct reduction of host cell death, promotion of neovascularization, and in a "bystander effect" on local inflammation. A number of cytokines secreted by adult stem/progenitor cells has been proposed to be responsible for the consistent beneficial effect reported in the early attempts to deliver different stem cell subsets to the injured myocardium. Aiming to maximize their beneficial activity on the diseased myocardium, the genetic modification of adult stem cells to enhance and/or control the secretion of specific cytokines would turn them into active drug delivery vectors. On the other hand, engineering biocompatible scaffolds as to release paracrine factors could result in multiple advantages: (1) achieve a local controlled release of the drug of interest, thus minimizing off-target effects, (2) enhance stem cell retention in the injured area and (3) boost the beneficial paracrine effects exerted by adult stem cells on the host tissue. In the present review, a critical overview of the state-of-the-art in the modification of stem cells and the functionalization of biocompatible scaffolds to deliver beneficial soluble factors to the injured myocardium is offered. Besides the number of concerns to be addressed before a clinical application can be foreseen for such concepts, this path could translate into the generation of active scaffolds as smart cell and drug delivery systems for cardiac repair. PMID:23745554

  18. Poly (D,L-lactide)/nano-hydroxyapatite composite scaffolds for bone tissue engineering and biocompatibility evaluation.

    PubMed

    Ren, Jie; Zhao, Peng; Ren, Tianbin; Gu, Shuying; Pan, Kefeng

    2008-03-01

    Biodegradable polymer/bioceramic composite scaffolds can overcome the limitations of conventional ceramic bone substitutes such as brittleness and difficulty in shaping. However, conventional methods for fabricating polymer/bioceramic composite scaffolds often use organic solvents (e.g., the solvent casting and particulate leaching (SC/PL) method), which might be harmful to cells or tissues. In this study, Poly (D,L-lactide)/nano-hydroxyapatite (PDLLA/NHA) composites were prepared by in-situ polymerization, and highly porous scaffolds were fabricated using a novel method, supercritical CO2/salt-leaching method (SC CO2/SL). The materials and scaffolds were investigated by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and gel permeation chromatography (GPC). GPC showed that the molecular weight of composites decreased with increase of NHA content. However, the water absorption and compressive strength increased dramatically. The SEM micrographs showed that the scaffolds with pore size about 250 microm were obtained by controlling parameters of SC CO2/SL. The biocompatibility of PDLLA/NHA porous scaffolds were evaluated in vitro and in vivo. The evaluation on the cytotoxicity were carried out by cell relative growth rate (RGR) method and cell direct contact method. The cytotoxicity of these scaffolds was in grade I according to ISO 10993-1. There was no toxicosis and death cases observed in acute systemic toxicity test. And histological observation of the tissue response (1 and 9 weeks after the implantation) showed that there are still some slight inflammation responses. PMID:17701303

  19. A biocompatible hybrid material with simultaneous calcium and strontium release capability for bone tissue repair.

    PubMed

    Almeida, J Carlos; Wacha, András; Gomes, Pedro S; Alves, Luís C; Fernandes, M Helena Vaz; Salvado, Isabel M Miranda; Fernandes, M Helena R

    2016-05-01

    The increasing interest in the effect of strontium in bone tissue repair has promoted the development of bioactive materials with strontium release capability. According to literature, hybrid materials based on the system PDMS-SiO2 have been considered a plausible alternative as they present a mechanical behavior similar to the one of the human bone. The main purpose of this study was to obtain a biocompatible hybrid material with simultaneous calcium and strontium release capability. A hybrid material, in the system PDMS-SiO2-CaO-SrO, was prepared with the incorporation of 0.05 mol of titanium per mol of SiO2. Calcium and strontium were added using the respective acetates as sources, following a sol-gel technique previously developed by the present authors. The obtained samples were characterized by FT-IR, solid-state NMR, and SAXS, and surface roughness was analyzed by 3D optical profilometry. In vitro studies were performed by immersion of the samples in Kokubo's SBF for different periods of time, in order to determine the bioactive potential of these hybrids. Surfaces of the immersed samples were observed by SEM, EDS and PIXE, showing the formation of calcium phosphate precipitates. Supernatants were analyzed by ICP, revealing the capability of the material to simultaneously fix phosphorus ions and to release calcium and strontium, in a concentration range within the values reported as suitable for the induction of the bone tissue repair. The material demonstrated to be cytocompatible when tested with MG63 osteoblastic cells, exhibiting an inductive effect on cell proliferation and alkaline phosphatase activity. PMID:26952443

  20. Biocompatibility and tissue interactions of a new filler material for medical use.

    PubMed

    Zarini, Elena; Supino, Rosanna; Pratesi, Graziella; Laccabue, Diletta; Tortoreto, Monica; Scanziani, Eugenio; Ghisleni, Gabriele; Paltrinieri, Saverio; Tunesi, Gianfranco; Nava, Maurizio

    2004-09-15

    Filler materials for medical use present limits, such as the induction of chronic inflammation and fibrosis. In the search for synthetic materials with improved biocompatible properties, a new polyacrylamide hydrogel, Aquamid (Contura SA, Montreux, Switzerland), has been investigated in preclinical systems. In cell cultures (endothelial cells and fibroblast), no or only transient biological effects were associated with 10% Aquamid exposure. The Aquamid-host interactions were examined in mice (10 mice per group) implanted subcutaneously or in the mammary fat pad with a very large volume (1.5 ml) of the material. Blood analysis, performed after 15 and 94 days (five mice per time for each group) to detect acute or late manifestations of toxicity, did not reveal relevant abnormalities in either group of Aquamid-bearing mice compared with control mice, except for a transient thrombocytopenia and a mild leukocytosis. Histological analysis of the pellet showed the presence of a thin, poorly vascularized cyst wall in implants. Only mild mesenchymal reparative and inflammatory processes were observed, even at longer observation times (more than 400 days). No alterations in any organ were detected. Despite the large volume implanted (approximately 5 percent of mouse body weight), the Aquamid pellet maintained its original size and shape without spreading or sticking to surrounding tissues. In conclusion, the study indicated a good tolerability of the new biopolymer in preclinical systems. The clinical utility of this new compound, if confirmed by clinical randomized trials showing its atoxic properties, could be in the field of aesthetic plastic surgery as a filler material for body contouring and in reconstructive surgery and above all in cancer patients to restore surgical defects. PMID:15468401

  1. Bio-Corrosion Resistance and Biocompatibility of a ZrTi-BASED Bmgmc as Potential Hard Tissue Implants

    NASA Astrophysics Data System (ADS)

    Huang, Xiaobo; Zou, Jiaojuan; Wang, Chan; Hang, Ruiqiang; Qiao, Junwei; Tang, Bin

    2013-07-01

    In this study, we compared the bio-corrosion resistance and biocompatibility of a ZrTi-based BMGMC (Zr58.5Ti14.3Ni4.9Cu6.1Nb5.2Be11.0). The Ti-6Al-4V alloy was used as a reference material. By utilizing the electrochemical measurements and M3T3 cell culture, the corrosion resistance and biocompatibility of this BMGMC were evaluated. The BMGMC displayed high positive corrosion potentials and low corrosion current densities, which indicated that this material exhibited a highly improved corrosion resistance than the Ti alloy. The cells could adhere on the surface of this BMGMC and exhibited improved cellular behaviors, such as cellular viability and cytoskeketal structure. In summary, the ZrTi-based BMGMC showed great potential for applications in the hard tissue implants.

  2. Biocompatibility and osteogenesis of calcium phosphate composite scaffolds containing simvastatin-loaded PLGA microspheres for bone tissue engineering.

    PubMed

    Zhang, Hao-Xuan; Xiao, Gui-Yong; Wang, Xia; Dong, Zhao-Gang; Ma, Zhi-Yong; Li, Lei; Li, Yu-Hua; Pan, Xin; Nie, Lin

    2015-10-01

    By utilizing a modified solid/oil/water (s/o/w) emulsion solvent evaporation technique, calcium phosphate composite scaffolds containing simvastatin-loaded PLGA microspheres (SIM-PLGA-CPC) were prepared in this study. We characterized the morphology, encapsulation efficiency and in vitro drug release of SIM-loaded PLGA microspheres as well as the macrostructure, pore size, porosity and mechanical strength of the scaffolds. Rabbit bone mesenchymal stem cells (BMSCs) were seeded onto SIM-PLGA-CPC scaffolds, and the proliferation, morphology, cell cycle and differentiation of BMSCs were investigated using the cell counting kit-8 (CCK-8) assay, scanning electron microscopy (SEM), flow cytometry, alkaline phosphatase (ALP) activity and alizarin red S staining, respectively. The results revealed that SIM-PLGA-CPC scaffolds were biocompatible and osteogenic in vitro. To determine the in vivo biocompatibility and osteogenesis of the scaffolds, both pure PLGA-CPC scaffolds and SIM-PLGA-CPC scaffolds were implanted in rabbit femoral condyles and microradiographically and histologically investigated. SIM-PLGA-CPC scaffolds exhibited good biocompatibility and could improve the efficiency of new bone formation. All these results suggested that the SIM-PLGA-CPC scaffolds fulfilled the basic requirements of bone tissue engineering scaffold and possessed application potentials in orthopedic surgery. PMID:25809455

  3. Comparison of biocompatibility and adsorption properties of different plastics for advanced microfluidic cell and tissue culture models.

    PubMed

    van Midwoud, Paul M; Janse, Arnout; Merema, Marjolijn T; Groothuis, Geny M M; Verpoorte, Elisabeth

    2012-05-01

    Microfluidic technology is providing new routes toward advanced cell and tissue culture models to better understand human biology and disease. Many advanced devices have been made from poly(dimethylsiloxane) (PDMS) to enable experiments, for example, to study drug metabolism by use of precision-cut liver slices, that are not possible with conventional systems. However, PDMS, a silicone rubber material, is very hydrophobic and tends to exhibit significant adsorption and absorption of hydrophobic drugs and their metabolites. Although glass could be used as an alternative, thermoplastics are better from a cost and fabrication perspective. Thermoplastic polymers (plastics) allow easy surface treatment and are generally transparent and biocompatible. This study focuses on the fabrication of biocompatible microfluidic devices with low adsorption properties from the thermoplastics poly(methyl methacrylate) (PMMA), polystyrene (PS), polycarbonate (PC), and cyclic olefin copolymer (COC) as alternatives for PDMS devices. Thermoplastic surfaces were oxidized using UV-generated ozone or oxygen plasma to reduce adsorption of hydrophobic compounds. Surface hydrophilicity was assessed over 4 weeks by measuring the contact angle of water on the surface. The adsorption of 7-ethoxycoumarin, testosterone, and their metabolites was also determined after UV-ozone treatment. Biocompatibility was assessed by culturing human hepatoma (HepG2) cells on treated surfaces. Comparison of the adsorption properties and biocompatibility of devices in different plastics revealed that only UV-ozone-treated PC and COC devices satisfied both criteria. This paper lays an important foundation that will help researchers make informed decisions with respect to the materials they select for microfluidic cell-based culture experiments. PMID:22444457

  4. The biocompatibility of carbon hydroxyapatite/β-glucan composite for bone tissue engineering studied with Raman and FTIR spectroscopic imaging.

    PubMed

    Sroka-Bartnicka, Anna; Kimber, James A; Borkowski, Leszek; Pawlowska, Marta; Polkowska, Izabela; Kalisz, Grzegorz; Belcarz, Anna; Jozwiak, Krzysztof; Ginalska, Grazyna; Kazarian, Sergei G

    2015-10-01

    The spectroscopic approaches of FTIR imaging and Raman mapping were applied to the characterisation of a new carbon hydroxyapatite/β-glucan composite developed for bone tissue engineering. The composite is an artificial bone material with an apatite-forming ability for the bone repair process. Rabbit bone samples were tested with an implanted bioactive material for a period of several months. Using spectroscopic and chemometric methods, we were able to determine the presence of amides and phosphates and the distribution of lipid-rich domains in the bone tissue, providing an assessment of the composite's bioactivity. Samples were also imaged in transmission using an infrared microscope combined with a focal plane array detector. CaF2 lenses were also used on the infrared microscope to improve spectral quality by reducing scattering artefacts, improving chemometric analysis. The presence of collagen and lipids at the bone/composite interface confirmed biocompatibility and demonstrate the suitability of FTIR microscopic imaging with lenses in studying these samples. It confirmed that the composite is a very good background for collagen growth and increases collagen maturity with the time of the bone growth process. The results indicate the bioactive and biocompatible properties of this composite and demonstrate how Raman and FTIR spectroscopic imaging have been used as an effective tool for tissue characterisation. PMID:26277184

  5. Alginate/Poly(γ-glutamic Acid) Base Biocompatible Gel for Bone Tissue Engineering

    PubMed Central

    Chan, Wing P.; Kung, Fu-Chen; Kuo, Yu-Lin; Yang, Ming-Chen; Lai, Wen-Fu Thomas

    2015-01-01

    A technique for synthesizing biocompatible hydrogels by cross-linking calcium-form poly(γ-glutamic acid), alginate sodium, and Pluronic F-127 was created, in which alginate can be cross-linked by Ca2+ from Ca–γ-PGA directly and γ-PGA molecules introduced into the alginate matrix to provide pH sensitivity and hemostasis. Mechanical properties, swelling behavior, and blood compatibility were investigated for each hydrogel compared with alginate and for γ-PGA hydrogel with the sodium form only. Adding F-127 improves mechanical properties efficiently and influences the temperature-sensitive swelling of the hydrogels but also has a minor effect on pH-sensitive swelling and promotes anticoagulation. MG-63 cells were used to test biocompatibility. Gelation occurred gradually through change in the elastic modulus as the release of calcium ions increased over time and caused ionic cross-linking, which promotes the elasticity of gel. In addition, the growth of MG-63 cells in the gel reflected nontoxicity. These results showed that this biocompatible scaffold has potential for application in bone materials. PMID:26504784

  6. Alginate/Poly(γ-glutamic Acid) Base Biocompatible Gel for Bone Tissue Engineering.

    PubMed

    Chan, Wing P; Kung, Fu-Chen; Kuo, Yu-Lin; Yang, Ming-Chen; Lai, Wen-Fu Thomas

    2015-01-01

    A technique for synthesizing biocompatible hydrogels by cross-linking calcium-form poly(γ-glutamic acid), alginate sodium, and Pluronic F-127 was created, in which alginate can be cross-linked by Ca(2+) from Ca-γ-PGA directly and γ-PGA molecules introduced into the alginate matrix to provide pH sensitivity and hemostasis. Mechanical properties, swelling behavior, and blood compatibility were investigated for each hydrogel compared with alginate and for γ-PGA hydrogel with the sodium form only. Adding F-127 improves mechanical properties efficiently and influences the temperature-sensitive swelling of the hydrogels but also has a minor effect on pH-sensitive swelling and promotes anticoagulation. MG-63 cells were used to test biocompatibility. Gelation occurred gradually through change in the elastic modulus as the release of calcium ions increased over time and caused ionic cross-linking, which promotes the elasticity of gel. In addition, the growth of MG-63 cells in the gel reflected nontoxicity. These results showed that this biocompatible scaffold has potential for application in bone materials. PMID:26504784

  7. Biocompatible, biodegradable polymer-based, lighter than or light as water scaffolds for tissue engineering and methods for preparation and use thereof

    NASA Technical Reports Server (NTRS)

    Laurencin, Cato T. (Inventor); Pollack, Solomon R. (Inventor); Levine, Elliot (Inventor); Botchwey, Edward (Inventor); Lu, Helen H. (Inventor); Khan, Mohammed Yusuf (Inventor)

    2012-01-01

    Scaffolds for tissue engineering prepared from biocompatible, biodegradable polymer-based, lighter than or light as water microcarriers and designed for cell culturing in vitro in a rotating bioreactor are provided. Methods for preparation and use of these scaffolds as tissue engineering devices are also provided.

  8. Preparation and Reinforcement of Dual‐Porous Biocompatible Cellulose Scaffolds for Tissue Engineering

    PubMed Central

    Pircher, Nicole; Fischhuber, David; Carbajal, Leticia; Strauß, Christine; Nedelec, Jean‐Marie; Kasper, Cornelia; Rosenau, Thomas

    2015-01-01

    1 Biocompatible cellulose‐based aerogels composed of nanoporous struts, which embed interconnected voids of controlled micron‐size, have been prepared employing temporary templates of fused porogens, reinforcement by interpenetrating PMMA networks and supercritical carbon dioxide drying. Different combinations of cellulose solvent (Ca(SCN)2/H2O/LiCl or [EMIm][OAc]/DMSO) and anti‐solvent (EtOH), porogen type (paraffin wax or PMMA spheres) and porogen size (various fractions in the range of 100–500 μm) as well as intensity of PMMA reinforcement have been investigated to tailor the materials for cell scaffolding applications. All aerogels exhibited an open and dual porosity (micronporosity >100 μm and nanoporosity extending to the low micrometer range). Mechanical properties of the dual‐porous aerogels under compressive stress were considerably improved by introduction of interpenetrating PMMA networks. The effect of the reinforcing polymer on attachment, spreading, and proliferation of NIH 3T3 fibroblast cells, cultivated on selected dual‐porous aerogels to pre‐evaluate their biocompatibility was similarly positive. PMID:26941565

  9. Laser-based three-dimensional multiscale micropatterning of biocompatible hydrogels for customized tissue engineering scaffolds

    PubMed Central

    Applegate, Matthew B.; Coburn, Jeannine; Partlow, Benjamin P.; Moreau, Jodie E.; Mondia, Jessica P.; Marelli, Benedetto; Kaplan, David L.; Omenetto, Fiorenzo G.

    2015-01-01

    Light-induced material phase transitions enable the formation of shapes and patterns from the nano- to the macroscale. From lithographic techniques that enable high-density silicon circuit integration, to laser cutting and welding, light–matter interactions are pervasive in everyday materials fabrication and transformation. These noncontact patterning techniques are ideally suited to reshape soft materials of biological relevance. We present here the use of relatively low-energy (< 2 nJ) ultrafast laser pulses to generate 2D and 3D multiscale patterns in soft silk protein hydrogels without exogenous or chemical cross-linkers. We find that high-resolution features can be generated within bulk hydrogels through nearly 1 cm of material, which is 1.5 orders of magnitude deeper than other biocompatible materials. Examples illustrating the materials, results, and the performance of the machined geometries in vitro and in vivo are presented to demonstrate the versatility of the approach. PMID:26374842

  10. A novel crosslinking method for improved tear resistance and biocompatibility of tissue based biomaterials.

    PubMed

    Tam, Hobey; Zhang, Will; Feaver, Kristen R; Parchment, Nathaniel; Sacks, Michael S; Vyavahare, Naren

    2015-10-01

    Over 300,000 heart valve replacements are performed annually to replace stenotic and regurgitant heart valves. Bioprosthetic heart valves (BHVs), derived from glutaraldehyde crosslinked (GLUT) porcine aortic valve leaflets or bovine pericardium are often used. However, valve failure can occur within 12-15 years due to calcification and/or progressive degeneration. In this study, we have developed a novel fabrication method that utilizes carbodiimide, neomycin trisulfate, and pentagalloyl glucose crosslinking chemistry (TRI) to better stabilize the extracellular matrix of porcine aortic valve leaflets. We demonstrate that TRI treated leaflets show similar biomechanics to GLUT crosslinked leaflets. TRI treated leaflets had better resistance to enzymatic degradation in vitro and demonstrated better tearing toughness after challenged with enzymatic degradation. When implanted subcutaneously in rats for up to 90 days, GLUT control leaflets calcified heavily while TRI treated leaflets resisted calcification, retained more ECM components, and showed better biocompatibility. PMID:26196535

  11. Laser-based three-dimensional multiscale micropatterning of biocompatible hydrogels for customized tissue engineering scaffolds.

    PubMed

    Applegate, Matthew B; Coburn, Jeannine; Partlow, Benjamin P; Moreau, Jodie E; Mondia, Jessica P; Marelli, Benedetto; Kaplan, David L; Omenetto, Fiorenzo G

    2015-09-29

    Light-induced material phase transitions enable the formation of shapes and patterns from the nano- to the macroscale. From lithographic techniques that enable high-density silicon circuit integration, to laser cutting and welding, light-matter interactions are pervasive in everyday materials fabrication and transformation. These noncontact patterning techniques are ideally suited to reshape soft materials of biological relevance. We present here the use of relatively low-energy (< 2 nJ) ultrafast laser pulses to generate 2D and 3D multiscale patterns in soft silk protein hydrogels without exogenous or chemical cross-linkers. We find that high-resolution features can be generated within bulk hydrogels through nearly 1 cm of material, which is 1.5 orders of magnitude deeper than other biocompatible materials. Examples illustrating the materials, results, and the performance of the machined geometries in vitro and in vivo are presented to demonstrate the versatility of the approach. PMID:26374842

  12. Tissue Engineering of Ureteral Grafts: Preparation of Biocompatible Crosslinked Ureteral Scaffolds of Porcine Origin

    PubMed Central

    Koch, Holger; Hammer, Niels; Ossmann, Susann; Schierle, Katrin; Sack, Ulrich; Hofmann, Jörg; Wecks, Mike; Boldt, Andreas

    2015-01-01

    The surgical reconstruction of ureteric defects is often associated with post-operative complications and requires additional medical care. Decellularized ureters originating from porcine donors could represent an alternative therapy. Our aim was to investigate the possibility of manufacturing decellularized ureters, the characteristics of the extracellular matrix (ECM) and the biocompatibility of these grafts in vitro/in vivo after treatment with different crosslinking agents. To achieve these goals, native ureters were obtained from pigs and were decellularized. The success of decellularization and the ECM composition were characterized by (immuno)histological staining methods and a DNA-assay. In vitro: scaffolds were crosslinked either with carbodiimide (CDI), genipin (GP), glutaraldehyde, left chemically untreated or were lyophilized. Scaffolds in each group were reseeded with Caco2, LS48, 3T3 cells, or native rat smooth muscle cells (SMC). After 2 weeks, the number of ingrown cells was quantified. In vivo: crosslinked scaffolds were implanted subcutaneously into rats and the type of infiltrating cells were determined after 1, 9, and 30 days. After decellularization, scaffold morphology and composition of ECM were maintained, all cellular components were removed, DNA destroyed and strongly reduced. In vitro: GP and CDI scaffolds revealed a higher number of ingrown 3T3 and SMC cells as compared to untreated scaffolds. In vivo: at day 30, implants were predominantly infiltrated by fibroblasts and M2 anti-inflammatory macrophages. A maximum of MMP3 was observed in the CDI group at day 30. TIMP1 was below the detection limit. In this study, we demonstrated the potential of decellularization to create biocompatible porcine ureteric grafts, whereas a CDI-crosslink may facilitate the remodeling process. The use of decellularized ureteric grafts may represent a novel therapeutic method in reconstruction of ureteric defects. PMID:26157796

  13. Diels-Alder functionalized carbon nanotubes for bone tissue engineering: in vitro/in vivo biocompatibility and biodegradability

    NASA Astrophysics Data System (ADS)

    Mata, D.; Amaral, M.; Fernandes, A. J. S.; Colaço, B.; Gama, A.; Paiva, M. C.; Gomes, P. S.; Silva, R. F.; Fernandes, M. H.

    2015-05-01

    The risk-benefit balance for carbon nanotubes (CNTs) dictates their clinical fate. To take a step forward at this crossroad it is compulsory to modulate the CNT in vivo biocompatibility and biodegradability via e.g. chemical functionalization. CNT membranes were functionalised combining a Diels-Alder cycloaddition reaction to generate cyclohexene (-C6H10) followed by a mild oxidisation to yield carboxylic acid groups (-COOH). In vitro proliferation and osteogenic differentiation of human osteoblastic cells were maximized on functionalized CNT membranes (p,f-CNTs). The in vivo subcutaneously implanted materials showed a higher biological reactivity, thus inducing a slighter intense inflammatory response compared to non-functionalized CNT membranes (p-CNTs), but still showing a reduced cytotoxicity profile. Moreover, the in vivo biodegradation of CNTs was superior for p,f-CNT membranes, likely mediated by the oxidation-induced myeloperoxidase (MPO) in neutrophil and macrophage inflammatory milieus. This proves the biodegradability faculty of functionalized CNTs, which potentially avoids long-term tissue accumulation and triggering of acute toxicity. On the whole, the proposed Diels-Alder functionalization accounts for the improved CNT biological response in terms of the biocompatibility and biodegradability profiles. Therefore, CNTs can be considered for use in bone tissue engineering without notable toxicological threats.The risk-benefit balance for carbon nanotubes (CNTs) dictates their clinical fate. To take a step forward at this crossroad it is compulsory to modulate the CNT in vivo biocompatibility and biodegradability via e.g. chemical functionalization. CNT membranes were functionalised combining a Diels-Alder cycloaddition reaction to generate cyclohexene (-C6H10) followed by a mild oxidisation to yield carboxylic acid groups (-COOH). In vitro proliferation and osteogenic differentiation of human osteoblastic cells were maximized on functionalized CNT

  14. Biocompatibility and biodegradation studies of PCL/β-TCP bone tissue scaffold fabricated by structural porogen method.

    PubMed

    Lu, Lin; Zhang, Qingwei; Wootton, David; Chiou, Richard; Li, Dichen; Lu, Bingheng; Lelkes, Peter; Zhou, Jack

    2012-09-01

    Three-dimensional printer (3DP) (Z-Corp) is a solid freeform fabrication system capable of generating sub-millimeter physical features required for tissue engineering scaffolds. By using plaster composite materials, 3DP can fabricate a universal porogen which can be injected with a wide range of high melting temperature biomaterials. Here we report results toward the manufacture of either pure polycaprolactone (PCL) or homogeneous composites of 90/10 or 80/20 (w/w) PCL/beta-tricalcium phosphate (β-TCP) by injection molding into plaster composite porogens fabricated by 3DP. The resolution of printed plaster porogens and produced scaffolds was studied by scanning electron microscopy. Cytotoxicity test on scaffold extracts and biocompatibility test on the scaffolds as a matrix supporting murine osteoblast (7F2) and endothelial hybridoma (EAhy 926) cells growth for up to 4 days showed that the porogens removal process had only negligible effects on cell proliferation. The biodegradation tests of pure PCL and PCL/β-TCP composites were performed in DMEM with 10 % (v/v) FBS for up to 6 weeks. The PCL/β-TCP composites show faster degradation rate than that of pure PCL due to the addition of β-TCP, and the strength of 80/20 PCL/β-TCP composite is still suitable for human cancellous bone healing support after 6 weeks degradation. Combining precisely controlled porogen fabrication structure, good biocompatibility, and suitable mechanical properties after biodegradation, PCL/β-TCP scaffolds fabricated by 3DP porogen method provide essential capability for bone tissue engineering. PMID:22669285

  15. Biocompatibility of a novel tissue connector for fixation of tracheostoma valves and shunt valves.

    PubMed

    Geertsema, A A; Schutte, H K; van Leeuwen, M B; Rakhorst, G; Schakenraad, J M; van Luyn, M J; Verkerke, G J

    1999-11-01

    Rehabilitation after laryngectomy often includes the use of a shunt valve and a tracheostoma valve to restore voice. To improve the fixation method of these valves, a new tissue connector has been developed, basically consisting of a ring that will be integrated into surrounding tracheal soft tissue. The valves can be placed in the ring. To test the principle of the tissue connector, a prototype consisting of a subcutaneous polypropylene mesh and a percutaneous titanium stylus was implanted into the backskin of 10 rats by a two-stage surgical procedure. We reasoned that if a firm connection can be realized with the skin, a firm connection with the trachea will also be possible. The subcutaneous part was implanted first, followed by the percutaneous part after 6 weeks. The complete tissue connector with surrounding tissue was removed 8 weeks later and examined histologically. The principle of the new tissue connector proved to be effective: hardly any epithelial downgrowth appeared, and adhesion of soft tissue was demonstrated. No infection or severe inflammation reaction was detected. The tissue connector seems appropriate for its intended use. PMID:10535811

  16. Acellular human glans extracellular matrix as a scaffold for tissue engineering: in vitro cell support and biocompatibility

    PubMed Central

    Egydio, Fernanda M.; Freitas, Luiz G.; Sayeg, Kleber; Laks, Marcus; Oliveira, Andréia S.; Almeida, Fernando G.

    2015-01-01

    ABSTRACT Objectives: Diseases of the genitourinary tract can lead to significant damage. Current reconstructive techniques are limited by tissue availability and compatibility. This study aims to assess if the decellularized human glans can be used as a biomaterial for penile reconstruction. Materials and Methods: Samples of the glans matrices were descellularized. We evaluate the presence of collagen type I and III, and elastic fibers. Biocompatibility assays were performed to assess the cytotoxic and non-cytotoxic interactions between the acellular matrix and 3T3 cells. The matrices were seeded with mesenchymal stem cells and were assessed for viability and integration of these cells. Biomechanical tests in native tissue, descellularized matrix and seeded matrix were performed to characterize their biomechanical properties. Results: The tissue architecture of the decellularized matrix of human glans was preserved as well as the maintenance of the biomechanical and biological properties. The analyzes of glans seeded with mesenchymal stem cells revealed the integration of these cells to the matrices, and its viability during two weeks “in vitro”. Conclusion: The decellularization process did not alter the biological and biomechanical characteristics of the human glans. When these matrices were seeded they were able to maintain the cells integrity and vitality. PMID:26689526

  17. Lithographic microfabrication of biocompatible polymers for tissue engineering and lab-on-a-chip applications

    NASA Astrophysics Data System (ADS)

    Balciunas, Evaldas; Jonusauskas, Linas; Valuckas, Vytautas; Baltriukiene, Daiva; Bukelskiene, Virginija; Gadonas, Roaldas; Malinauskas, Mangirdas

    2012-06-01

    In this work, a combination of Direct Laser Writing (DLW), PoliDiMethylSiloxane (PDMS) soft lithography and UV lithography was used to create cm- scale microstructured polymer scaolds for cell culture experiments out of dierent biocompatible materials: novel hybrid organic-inorganic SZ2080, PDMS elastomer, biodegradable PEG- DA-258 and SU-8. Rabbit muscle-derived stem cells were seeded on the fabricated dierent periodicity scaolds to evaluate if the relief surface had any eect on cell proliferation. An array of microlenses was fabricated using DLW out of SZ2080 and replicated in PDMS and PEG-DA-258, showing good potential applicability of the used techniques in many other elds like micro- and nano- uidics, photonics, and MicroElectroMechanical Systems (MEMS). The synergetic employment of three dierent fabrication techniques allowed to produce desired objects with low cost, high throughput and precision as well as use materials that are dicult to process by other means (PDMS and PEG-DA-258). DLW is a relatively slow fabrication method, since the object has to be written point-by-point. By applying PDMS soft lithography, we were enabled to replicate laser-fabricated scaolds for stem cell growth and micro-optical elements for lab-on-a-chip applications with high speed, low cost and good reproducible quality.

  18. Histological Features and Biocompatibility of Bone and Soft Tissue Substitutes in the Atrophic Alveolar Ridge Reconstruction.

    PubMed

    Maiorana, Carlo; Beretta, Mario; Rancitelli, Davide; Grossi, Giovanni Battista; Cicciù, Marco; Herford, Alan Scott

    2016-01-01

    The reconstruction of the atrophic alveolar ridges for implant placement is today a common procedure in dentistry daily practice. The surgical reconstruction provides for the optimization of the supporting bone for the implants and a restoration of the amount of keratinized gingiva for esthetic and functional reasons. In the past, tissue regeneration has been performed with autogenous bone and free gingival or connective tissue grafts. Nowadays, bone substitutes and specific collagen matrix allow for a complete restoration of the atrophic ridge without invasive harvesting procedures. A maxillary reconstruction of an atrophic ridge by means of tissue substitutes and its histological features are then presented. PMID:27022489

  19. Histological Features and Biocompatibility of Bone and Soft Tissue Substitutes in the Atrophic Alveolar Ridge Reconstruction

    PubMed Central

    Rancitelli, Davide; Grossi, Giovanni Battista; Herford, Alan Scott

    2016-01-01

    The reconstruction of the atrophic alveolar ridges for implant placement is today a common procedure in dentistry daily practice. The surgical reconstruction provides for the optimization of the supporting bone for the implants and a restoration of the amount of keratinized gingiva for esthetic and functional reasons. In the past, tissue regeneration has been performed with autogenous bone and free gingival or connective tissue grafts. Nowadays, bone substitutes and specific collagen matrix allow for a complete restoration of the atrophic ridge without invasive harvesting procedures. A maxillary reconstruction of an atrophic ridge by means of tissue substitutes and its histological features are then presented. PMID:27022489

  20. Tissue-Integratable and Biocompatible Photogelation by the Imine Crosslinking Reaction.

    PubMed

    Yang, Yunlong; Zhang, Jieyuan; Liu, Zhenzhen; Lin, Qiuning; Liu, Xiaolin; Bao, Chunyan; Wang, Yang; Zhu, Linyong

    2016-04-01

    A novel photogelling mechanism by the phototriggered-imine-crosslinking (PIC) reaction is demonstrated. Hyaluronic acid grafted with o-nitrobenzene, a photogenerated aldehyde group, can quickly photo-crosslink with amino-bearing polymers or proteins. Once the in situ photogelling on a wound occurs, the PIC gelling process can well integrate a hydrogel with surrounding tissue by covalent bonding, thus making it a powerful tool for tissue engineering and regenerative medicine. PMID:26840751

  1. In vitro degradation and in vivo biocompatibility of poly(lactic acid) mesh for soft tissue reinforcement in vaginal surgery.

    PubMed

    de Tayrac, Renaud; Chentouf, Samir; Garreau, Henri; Braud, Christian; Guiraud, Isabelle; Boudeville, Philippe; Vert, Michel

    2008-05-01

    This study was aimed at evaluating the in vitro degradation, the in vivo biocompatibility and at comparing the effects of two methods of sterilization on poly(L-lactic acid) (PLA(94)) resorbable mesh. The mesh was manufactured to be used as surgical soft tissue reinforcement in the vaginal area. Samples of 100 mg of PLA(94) mesh (10 x 10 mm(2)) were immersed in isoosmolar 0.13M, pH 7.4 phosphate buffer solution at 37 degrees C, during 12 months. The hydrolytic degradation up to 12 months after immersion was monitored by measuring weight loss, mesh area changes, and by various analytical techniques namely Differential scanning calorimetry (DSC), capillary zone electrophoresis (CZE), size exclusion chromatography (SEC), and environmental scanning electron microscopy (ESEM). Specimens of nonsterilized, ethylene-oxide (ETO) sterilized, and gamma-ray sterilized PLA(94) mesh were compared. Fifteen samples were implanted in an incisional hernia Wistar rat model. Histopathology was performed up to 90 days after implantation to evaluate the inflammatory response and the collagen deposition. Although the decrease of molecular weight due to polymer chain scissions started 6 weeks after in vitro immersion, water-soluble degradation products and decrease of tensile strength appeared after 8 months only. Analyses showed also that ETO sterilization did not affect the degradation of the PLA(94) mesh. In contrast, gamma-ray sterilization increased very much the sensitivity of the mesh to the hydrolytic degradation. In vivo, the PLA(94) mesh exhibited good biocompatibility over the investigated time period. PMID:18161812

  2. Biodegradable, Elastomeric, and Intrinsically Photoluminescent Poly(Silicon-Citrates) with high Photostability and Biocompatibility for Tissue Regeneration and Bioimaging.

    PubMed

    Du, Yuzhang; Xue, Yumeng; Ma, Peter X; Chen, Xiaofeng; Lei, Bo

    2016-02-01

    Biodegradable polymer biomaterials with intrinsical photoluminescent properties have attracted much interest, due to their potential advantages for tissue regeneration and noninvasive bioimaging. However, few of current biodegradable polymers possess tunable intrinsically fluorescent properties, such as high photostability, fluorescent lifetime, and quantum field, and strong mechanical properties for meeting the requirements of biomedical applications. Here, by a facile one-step thermal polymerization, elastomeric poly(silicone-citrate) (PSC) hybrid polymers are developed with controlled biodegradability and mechanical properties, tunable inherent fluorescent emission (up to 600 nm), high photostability (beyond 180 min for UV and six months for natural light), fluorescent lifetime (near 10 ns) and quantum yield (16%-35%), high cellular biocompatibility, and minimal inflammatory response in vivo, which provide advantages over conventional fluorescent dyes, quantum dots, and current fluorescent polymers. The promising applications of PSC hybrids for cell and implants imaging in vitro and in vivo are successfully demonstrated. The development of elastomeric PSC polymer may provide a new strategy in synthesizing new inorganic-organic hybrid photo-luminescent materials for tissue regeneration and bioimaging applications. PMID:26687865

  3. Effect of surface texture by ion beam sputtering on implant biocompatibility and soft tissue attachment

    NASA Technical Reports Server (NTRS)

    Gibbons, D. F.

    1977-01-01

    The objectives in this report were to use the ion beam sputtering technique to produce surface textures on polymers, metals, and ceramics. The morphology of the texture was altered by varying both the width and depth of the square pits which were formed by ion beam erosion. The width of the ribs separating the pits were defined by the mask used to produce the texture. The area of the surface containing pits varies as the width was changed. The biological parameters used to evaluate the biological response to the texture were: (1) fibrous capsule and inflammatory response in subcutaneous soft tissue; (2) strength of the mechanical attachment of the textured surface by the soft tissue; and (3) morphology of the epidermal layer interfacing the textured surface of percutaneous connectors. Because the sputter yield on teflon ribs was approximately an order of magnitude larger than any other material the majority of the measurements presented in the report were obtained with teflon.

  4. Biocompatible, Biodegradable, and Electroactive Polyurethane-Urea Elastomers with Tunable Hydrophilicity for Skeletal Muscle Tissue Engineering.

    PubMed

    Chen, Jing; Dong, Ruonan; Ge, Juan; Guo, Baolin; Ma, Peter X

    2015-12-30

    It remains a challenge to develop electroactive and elastic biomaterials to mimic the elasticity of soft tissue and to regulate the cell behavior during tissue regeneration. We designed and synthesized a series of novel electroactive and biodegradable polyurethane-urea (PUU) copolymers with elastomeric property by combining the properties of polyurethanes and conducting polymers. The electroactive PUU copolymers were synthesized from amine capped aniline trimer (ACAT), dimethylol propionic acid (DMPA), polylactide, and hexamethylene diisocyanate. The electroactivity of the PUU copolymers were studied by UV-vis spectroscopy and cyclic voltammetry. Elasticity and Young's modulus were tailored by the polylactide segment length and ACAT content. Hydrophilicity of the copolymer films was tuned by changing DMPA content and doping of the copolymer. Cytotoxicity of the PUU copolymers was evaluated by mouse C2C12 myoblast cells. The myogenic differentiation of C2C12 myoblasts on copolymer films was also studied by analyzing the morphology of myotubes and relative gene expression during myogenic differentiation. The chemical structure, thermal properties, surface morphology, and processability of the PUU copolymers were characterized by NMR, FT-IR, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and solubility testing, respectively. Those biodegradable electroactive elastic PUU copolymers are promising materials for repair of soft tissues such as skeletal muscle, cardiac muscle, and nerve. PMID:26641320

  5. Cytotoxicity of Cyanoacrylate-Based Tissue Adhesives and Short-Term Preclinical In Vivo Biocompatibility in Abdominal Hernia Repair

    PubMed Central

    Rodríguez, Marta; Pérez-Köhler, Bárbara; Kühnhardt, Andreé; Fernández-Gutiérrez, Mar; San Román, Julio; Bellón, Juan Manuel

    2016-01-01

    Background Cyanoacrylate(CA)-based tissue adhesives, although not widely used, are a feasible option to fix a mesh during abdominal hernia repair, due to its fast action and great bond strength. Their main disadvantage, toxicity, can be mitigated by increasing the length of their alkyl chain. The objective was to assess the in vitro cytotoxicity and in vivo biocompatibility in hernia repair of CAs currently used in clinical practice (Glubran(n-butyl) and Ifabond(n-hexyl)) and a longer-chain CA (OCA(n-octyl)), that has never been used in the medical field. Methods Formaldehyde release and cytotoxicity of unpolymerized(UCAs) and polymerized CAs(PCAs) were evaluated by macroscopic visual assessment, flow cytometry and Alamar Blue assays. In the preclinical evaluation, partial defects were created in the rabbit abdominal wall and repaired by fixing polypropylene prostheses using the CAs. At 14 days post-surgery, animals were euthanized for morphology, macrophage response and cell damage analyses. Results Formaldehyde release was lower as the molecular weight of the monomer increased. The longest side-chain CA(OCA) showed the highest cytotoxicity in the UCA condition. However, after polymerization, was the one that showed better behavior on most occasions. In vivo, all CAs promoted optimal mesh fixation without displacements or detachments. Seroma was evident with the use of Glubran, (four of six animals: 4/6) and Ifabond (2/6), but it was reduced with the use of OCA (1/6). Significantly greater macrophage responses were observed in groups where Glubran and Ifabond were used vs. sutures and OCA. TUNEL-positive cells were significantly higher in the Glubran and OCA groups vs. the suture group. Conclusions Although mild formaldehyde release occurred, OCA was the most cytotoxic during polymerization but the least once cured. The CAs promoted proper mesh fixation and have potential to replace traditional suturing techniques in hernia repair; the CAs exhibited good tissue

  6. Biodegradation, biocompatibility, and osteoconduction evaluation of collagen-nanohydroxyapatite cryogels for bone tissue regeneration.

    PubMed

    Salgado, Christiane Laranjo; Grenho, Liliana; Fernandes, Maria Helena; Colaço, Bruno Jorge; Monteiro, Fernando Jorge

    2016-01-01

    Designing biomimetic biomaterials inspired by the natural complex structure of bone and other hard tissues is still a challenge nowadays. The control of the biomineralization process onto biomaterials should be evaluated before clinical application. Aiming at bone regeneration applications, this work evaluated the in vitro biodegradation and interaction between human bone marrow stromal cells (HBMSC) cultured on different collagen/nanohydroxyapatite cryogels. Cell proliferation, differentiation, morphology, and metabolic activity were assessed through different protocols. All the biocomposite materials allowed physiologic apatite deposition after incubation in simulated body fluid and the cryogel with the highest nanoHA content showed to have the highest mechanical strength (DMA). The study clearly showed that the highest concentration of nanoHA granules on the cryogels were able to support cell type's survival, proliferation, and individual functionality in a monoculture system, for 21 days. In fact, the biocomposites were also able to differentiate HBMSCs into osteoblastic phenotype. The composites behavior was also assessed in vivo through subcutaneous and bone implantation in rats to evaluate its tissue-forming ability and degradation rate. The cryogels Coll/nanoHA (30 : 70) promoted tissue regeneration and adverse reactions were not observed on subcutaneous and bone implants. The results achieved suggest that scaffolds of Coll/nanoHA (30 : 70) should be considered promising implants for bone defects that present a grotto like appearance with a relatively small access but a wider hollow inside. This material could adjust to small dimensions and when entering into the defect, it could expand inside and remain in close contact with the defect walls, thus ensuring adequate osteoconductivity. PMID:26179958

  7. Highly conductive stretchable and biocompatible electrode-hydrogel hybrids for advanced tissue engineering.

    PubMed

    Sasaki, Masato; Karikkineth, Bijoy Chandapillai; Nagamine, Kuniaki; Kaji, Hirokazu; Torimitsu, Keiichi; Nishizawa, Matsuhiko

    2014-11-01

    Hydrogel-based, molecular permeable electronic devices are considered to be promising for electrical stimulation and recording of living tissues, either in vivo or in vitro. This study reports the fabrication of the first hydrogel-based devices that remain highly electrically conductive under substantial stretch and bending. Using a simple technique involving a combination of chemical polymerization and electropolymerization of poly (3,4-ethylenedioxythiophene) (PEDOT), a tight bonding of a conductive composite of PEDOT and polyurethane (PU) to an elastic double-network hydrogel is achieved to make fully organic PEDOT/PU-hydrogel hybrids. Their response to repeated bending, mechanical stretching, hydration-dessication cycles, storage in aqueous condition for up to 6 months, and autoclaving is assessed, demonstrating excellent stability, without any mechanical or electrical damage. The hybrids exhibit a high electrical conductivity of up to 120 S cm(-1) at 100% elongation. The adhesion, proliferation, and differentiation of neural and muscle cells cultured on these hybrids are demonstrated, as well as the fabrication of 3D hybrids, advancing the field of tissue engineering with integrated electronics. PMID:24912988

  8. Fabrication of biocompatible electro-conductive silk films with natural compounds for tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Dimitrakakis, Nikolaos

    In the present study electro conductive natural compounds are incorporated in silk based films, and the effects on film conductivity and dissolution are studied. Natural conducting compounds melanin and riboflavin were blended with silk to increase conductivity. Other compounds such as Fe(0) powder ferrofluid and NaCl solution also improved conductivity. Film properties and dissolution were studied for the different blends, and tuned using addition of glycerol and horseradish peroxidase cross-linking. Techniques such as electrospinning, doctor blade, spin coating, and paper-like film fabrication techniques were also explored to generate films with controlled dimensions and properties. The findings suggest that the incorporation of riboflavin along with NaCl and glycerol in silk films, along with water vapor annealing results in semiconductor films. More specifically, the two compositions of the films that exhibited highest conductivity contain 2 % w/v silk, 20 % w/v glycerol, 2 % w/v polyethylene oxide (PEO), 30 % v/v phosphate buffered saline (PBS) and 5 % w/v silk, 20 % w/v glycerol, 10 % w/v NaCl with conductivities of 5.72*10-2 S/m and 5.96*10-2 S/m at 20 °C. When silk is doped with riboflavin, NaCl, and glycerol, semiconducting behavior similar to drinking water conductivity is observed. Mass loss studies of the films included the immersion of the films for 7 days in 37° C in PBS. Film processing included samples that were heated for 2 hours in 60 °C immediately after casting, as well as those cured at room temperature. The results indicated that the heated samples provided the lowest mass loss of approximately 27 %. In conclusion, the present study demonstrates the correlation between composition and processing of silk films with their conductivity. These semiconductive films have the potential to be applied in tissue engineering applications such as nerve conduits, where conductivity plays an instrumental role in tissue restoration.

  9. Extraction and characterization of biocompatible hydroxyapatite from fresh water fish scales for tissue engineering scaffold.

    PubMed

    Panda, Niladri Nath; Pramanik, Krishna; Sukla, Lala Behari

    2014-03-01

    In bone tissue engineering, porous hydroxyapatite (HAp) is used as filling material for bone defects, augmentation, artificial bone graft and scaffold material. The present paper compares the preparation and characterization of HAp from fish scale (FS) and synthetic body fluid (SBF) solution. Thermo gravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and particle size analysis of the samples have been performed. The analysis indicates that synthesized HAp consists of sub-micron HAp particle with Ca/P ratio corresponding to FS and SBF 1.62 and 1.71, respectively. MTT assay and quantitative DNA analysis show growth and proliferation of cells over the HA scaffold with the increase in time. The shape and size (morphology) of mesenchymal stem cells after 3 days show a transition from rounded shape to elongated and flattened shape expressing its spreading behavior. These results confirm that HAp bio-materials from fish scale are physico-chemically and biologically equivalent to the chemically synthesized HAp from SBF. Biological HAp, thus, possesses a great potential for conversion of industrial by-product into highly valuable compounds using simple effective and novel processes. PMID:23846299

  10. Bimodal fibrous structures for tissue engineering: Fabrication, characterization and in vitro biocompatibility.

    PubMed

    Tiwari, Arjun Prasad; Joshi, Mahesh Kumar; Kim, Jeong In; Unnithan, Afeesh Rajan; Lee, Joshua; Park, Chan Hee; Kim, Cheol Sang

    2016-08-15

    We report for the first time a polycaprolactone-human serum albumin (PCL-HSA) membrane with bimodal structures comprised of spider-web-like nano-nets and conventional fibers via facile electro-spinning/netting (ESN) technique. Such unique controllable morphology was developed by electrospinning the blend solution of PCL (8wt% in HFIP 1,1,1,3,3,3,-Hexafluoro-2-propanol) and HSA (10wt% deionized water). The phase separation during electrospinning caused the formation of bimodal structure. Various processing factors such as applied voltage, feeding rate, and distance between nozzle tip and collector were found responsible for the formation and distribution of the nano-nets throughout the nanofibrous mesh. Field emission electron microscopy (FE-SEM) confirmed that the nano-nets were composed of interlinked nanowires with an ultrathin diameter (10-30nm). When compared with a pure PCL membrane, the membrane containing nano-nets was shown to have better support for cellular activities as determined by cell viability and attachment assays. These results revealed that the blending of albumin, a hydrophilic biomolecule, with PCL, a hydrophobic polymer, proves to be an outstanding approach to developing membranes with controlled spider-web-like nano-nets for tissue engineering. PMID:27179176

  11. Degradation and biocompatibility of porous nano-hydroxyapatite/polyurethane composite scaffold for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Dong, Zhihong; Li, Yubao; Zou, Qin

    2009-04-01

    Porous scaffold containing 30 wt% nano-hydroxyapatite (n-HA) and 70 wt% polyurethane (PU) from castor oil was prepared by a foaming method and investigated by X-ray diffraction (XRD), Fourier transform infrared absorption (FTIR), scanning electron microscopy (SEM) techniques. The results show that n-HA particles disperse homogeneously in the PU matrix. The porous scaffold has not only macropores of 100-800 μm in size but also a lot of micropores on the walls of macropores. The porosity and compressive strength of scaffold are 80% and 271 kPa, respectively. After soaking in simulated body fluid (SBF), hydrolysis and deposition partly occur on the scaffold. The biological evaluation in vitro and in vivo shows that the n-HA/PU scaffold is non-cytotoxic and degradable. The porous structure provides a good microenvironment for cell adherence, growth and proliferation. The n-HA/PU composite scaffold can be satisfied with the basic requirement for tissue engineering, and has the potential to be applied in repair and substitute of human menisci of the knee-joint and articular cartilage.

  12. Micro- and Nanostructured Biomaterials for Sutureless Tissue Repair.

    PubMed

    Frost, Samuel J; Mawad, D; Hook, J; Lauto, Antonio

    2016-02-18

    Sutureless procedures for wound repair and closure have recently integrated nanostructured devices to improve their effectiveness and clinical outcome. This review highlights the major advances in gecko-inspired bioadhesives that relies mostly on van der Waals bonding forces. These are challenged by the moist environment of surgical settings that weaken adherence to tissue. The incorporation of nanoparticles in biomatrices and their role in tissue repair and drug delivery is also reviewed with an emphasis on procedures involving adhesives that are laser-activated. Nanostructured adhesive devices have the advantage of being minimally invasive to tissue, can seal wounds, and deliver drugs in situ. All these tasks are very difficult to accomplish by sutures or staples that are invasive to host organs and often cause scarring. PMID:26725593

  13. In Vivo Neural Tissue Engineering: Cylindrical Biocompatible Hydrogels That Create New Neural Tracts in the Adult Mammalian Brain.

    PubMed

    Clark, Amanda R; Carter, Arrin B; Hager, Lydia E; Price, Elmer M

    2016-08-01

    Individuals with neurodegenerative disorders or brain injury have few treatment options and it has been proposed that endogenous adult neural stem cells can be harnessed to repopulate dysfunctional nonneurogenic regions of the brain. We have accomplished this through the development of rationally designed hydrogel implants that recruit endogenous cells from the adult subventricular zone to create new relatively long tracts of neuroblasts. These implants are biocompatible and biodegradable cylindrical hydrogels consisting of fibrin and immobilized neurotrophic factors. When implanted into rat brain such that the cylinder intersected the migratory path of endogenous neural progenitors (the rostral migratory stream) and led into the nonneurogenic striatum, we observed a robust neurogenic response in the form of migrating neuroblasts with long (>100 μm) complex neurites. The location of these new neural cells in the striatum was directly coincident with the original track of the fibrin implant, which itself had completely degraded, and covered a significant area and distance (>2.5 mm). We also observed a significant number of neuroblasts in the striatal region between the implant track and the lateral ventricle. When these fibrin cylinders were implanted into hemiparkinson rats, correction of parkinsonian behavior was observed. There were no obvious behavioral, inflammatory or tumorigenic sequelae as a consequence of the implants. In conclusion, we have successfully engineered neural tissue in vivo, using neurogenic biomaterials cast into a unique cylindrical architecture. These results represent a novel approach to efficiently induce neurogenesis in a controlled and targeted manner, which may lead toward a new therapeutic modality for neurological disorders. PMID:27295980

  14. Biocompatibility evaluation of dicalcium phosphate/calcium sulfate/poly (amino acid) composite for orthopedic tissue engineering in vitro and in vivo.

    PubMed

    Wang, Peng; Liu, Pengzheng; Peng, Haitao; Luo, Xiaoman; Yuan, Huipin; Zhang, Juncai; Yan, Yonggang

    2016-08-01

    In vitro cytocompatibility of ternary biocomposite of dicalcium phosphate (DCP) and calcium sulfate (CS) containing 40 wt% poly (amino acid) (PAA) was evaluated using L929 fibroblasts and MG-63 osteoblast-like cells. Thereafter, the biocompatibility of biocomposite in vivo was investigated using an implantation in muscle and bone model. In vitro L929 and MG-63 cell culture experiments showed that the composite and PAA polymer were noncytotoxic and allowed cells to adhere and proliferate. The scanning electron microscope (SEM) confirmed that two kinds of cells maintained their phenotype on all of samples surfaces. Moreover, the DCP/CS/PAA composite showed higher cellular viability than that of PAA; meanwhile, the cell proliferation and ALP activity were much higher when DCP/CS had added into PAA. After implanted in muscle of rabbits for 12 weeks, the histological evaluation indicated that the composite exhibited excellent biocompatibility and no inflammatory responses were found. When implanted into bone defects of femoral condyle of rabbits, the composite was combined directly with the host bone tissue without fibrous capsule tissue, which shown good biocompatibility and osteoconductivity. Thus, this novel composite may have potential application in the clinical setting. PMID:27126299

  15. Biocompatibility of plasma-treated poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nanofiber mats modified by silk fibroin for bone tissue regeneration.

    PubMed

    Unalan, Irem; Colpankan, Oylum; Albayrak, Aylin Ziylan; Gorgun, Cansu; Urkmez, Aylin Sendemir

    2016-11-01

    The objective of this study was to produce biocompatible plasma-treated and silk-fibroin (SF) modified poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofiber mats. The mats were plasma-treated using O2 or N2 gas to increase their hydrophilicity followed by SF immobilization for the improvement of biocompatibility. Contact angle measurements and SEM showed increased hydrophilicity and no disturbed morphology, respectively. Cell proliferation assay revealed that SF modification together with N2 plasma (PS/N2) promoted higher osteoblastic (SaOs-2) cell viability. Although, O2 plasma triggered more mineral formation on the mats, it showed poor cell viability. Consequently, the PS/N2 nanofiber mats would be a potential candidate for bone tissue engineering applications. PMID:27524087

  16. Reengineered graft copolymers as a potential alternative for the bone tissue engineering application by inducing osteogenic markers expression and biocompatibility.

    PubMed

    Thangavelu, Muthukumar; R Narasimha, Raghavan; Adithan, Aravinthan; A, Chandrasekaran; Jong-Hoon, Kim; Thotapalli Parvathaleswara, Sastry

    2016-07-01

    Composite scaffolds of nano-hydroxyapatite with demineralized bone matrix were prepared and they were graft copolymerized for better bone regeneration and drug delivery applications. The graft copolymers were characterized for their physiochemical properties using conventional methods like FTIR, TGA, XRD and SEM. The scaffolds were seeded with 3T3 and MG63 cells for studying their biocompatibility and their temporal expression of ALP activity, the rate of calcium deposition and their gene expression of collagen type I (Coll-1), osteopontin (OP), osteonectin (ON), and osteocalcin (OC) were studied. In vivo studies were conducted using sub-cutaneous implantation models in male Wister rats for 6 months. Periodic radiography and post-autopsy histopathology was analysed at 15days, 1, 2, 3, 4, 5, and 6 months. The obtained in vitro results clearly confirm that the bone scaffolds prepared in this study are biocompatible, superior osteoinductivity, capable of supporting growth, maturation of MG 63 osteoblast like cells; the gene expression profile revealed that the material is capable of supporting the in vitro growth and maturation of osteoblast-like cells and maturation. The in vivo results stand a testimony to the in vitro results in proving the biocompatibility and osteoinductivity of the materials. PMID:26998863

  17. A vascular tissue engineering scaffold with core-shell structured nano-fibers formed by coaxial electrospinning and its biocompatibility evaluation.

    PubMed

    Duan, Nannan; Geng, Xue; Ye, Lin; Zhang, Aiying; Feng, Zengguo; Guo, Lianrui; Gu, Yongquan

    2016-01-01

    In this article, a tubular vascular tissue engineering scaffold with core-shell structured fibers was produced by coaxial electrospinning at an appropriate flow rate ratio between the inner and outer solution. PCL was selected as the core to provide the mechanical property and integrity to the scaffold while collagen was used as the shell to improve the attachment and proliferation of vascular cells due to its excellent biocompatibility. The fine core-shell structured fibers were demonstrated by scanning electron microscope and transmission electron microscope observations. Subsequently, the collagen shell was crosslinked by genipin and further bound with heparin. The crosslinking process was confirmed by the increasing of tensile strength, swelling ratio and thermogravimetric analysis measurements while the surface heparin content was characterized by means of a UV-spectrophotometer and activated partial thromboplastin time tests. Furthermore, the mechanical properties such as stitch strength and bursting pressure of the as-prepared scaffold were measured. Moreover, the biocompatibility of the scaffold was evaluated by cytotoxicity investigation with L929 cells via MTT assay. Endothelial cell adhesion assessments were conducted to reveal the possibility of the formation of an endothelial cell layer on the scaffold surface, while the ability of smooth muscle cell penetration into the scaffold wall was also assessed by confocal laser scanning microscopy. The as-prepared core-shell structured scaffold showed promising potential for use in vascular tissue engineering. PMID:27206161

  18. Nb-C nanocomposite films with enhanced biocompatibility and mechanical properties for hard-tissue implant applications.

    PubMed

    Yate, Luis; Coy, L Emerson; Gregurec, Danijela; Aperador, Willian; Moya, Sergio E; Wang, Guocheng

    2015-03-25

    One of the key challenges in engineering of orthopedic implants is to "bioactivate" their surface by using different surface techniques and materials. Carbon, especially amorphous (a-C) and diamond-like carbon down (DLC) films have attracted much attention in biomedical fields due to their biocompatibility and low coefficient of friction. However, they are unsuitable for uses as a "bioactivity enhancer" of orthopedic implants due to their bioinertness. In this work, we use the nonreactive magnetron sputtering technique to produce a-C films including the biocompatible niobium (Nb) element to alter the surface chemistry and nanotopography of the a-C films with the purpose of bioactivating the a-C film coated implants. Results show that the nanocomposite films (Nb-C) formed by the addition of Nb into the a-C films not only have improved corrosion resistance, but also possess enhanced mechanical properties (nanohardness, Young's modulus and superelastic recovery). Preosteoblasts (MC3T3-E1) cultured on the Nb-C films have enhanced adhesion and upregulated alkaline phosphatase (ALP) activity, compared to those cultured on the a-C film and TiO2 films used as a control, which are thought to be ascribed to the combined effects of the changes in surface chemistry and the refinement of the nanotopography caused by the addition of Nb. PMID:25738650

  19. Vertical anisotropic microfibers for a gecko-inspired adhesive.

    PubMed

    Tamelier, John; Chary, Sathya; Turner, Kimberly L

    2012-06-12

    Geckos are able to adhere strongly and release easily from surfaces because the structurally anisotropic fibers on their toes naturally exhibit force anisotropy based on the direction of articulation. Here, semicircular fibers, with varying amounts of contact area on the two faces, are investigated to ascertain whether fiber shape can be used to gain anisotropy in shear and shear adhesion forces. Testing of 10-μm-diameter polydimethylsiloxane (PDMS) fibers against a 4-mm-diameter flat glass puck show that shear and shear adhesion forces were two to five times greater when in-plane movement caused the flat face, rather than the curved face, of the fiber to come in contact with the glass puck. The directional adhesion and shear force anisotropy results are close to theoretical approximations using the Kendall peel model and clearly demonstrate how fiber shape may be used to influence the properties of the adhesive. This result has broad applicability, and by combining the results shown here with other current vertical and angled designs, synthetic adhesives can be further improved to behave more like their natural counterparts. PMID:22568809

  20. Long-term biocompatibility, imaging appearance and tissue effects associated with delivery of a novel radiopaque embolization bead for image-guided therapy.

    PubMed

    Sharma, Karun V; Bascal, Zainab; Kilpatrick, Hugh; Ashrafi, Koorosh; Willis, Sean L; Dreher, Matthew R; Lewis, Andrew L

    2016-10-01

    The objective of this study was to undertake a comprehensive long-term biocompatibility and imaging assessment of a new intrinsically radiopaque bead (LC Bead LUMI™) for use in transarterial embolization. The sterilized device and its extracts were subjected to the raft of ISO10993 biocompatibility tests that demonstrated safety with respect to cytotoxicity, mutagenicity, blood contact, irritation, sensitization, systemic toxicity and tissue reaction. Intra-arterial administration was performed in a swine model of hepatic arterial embolization in which 0.22-1 mL of sedimented bead volume was administered to the targeted lobe(s) of the liver. The beads could be visualized during the embolization procedure with fluoroscopy, DSA and single X-ray snapshot imaging modalities. CT imaging was performed before and 1 h after embolization and then again at 7, 14, 30 and 90 days. LC Bead LUMI™ could be clearly visualized in the hepatic arteries with or without administration of IV contrast and appeared more dense than soluble contrast agent. The CT density of the beads did not deteriorate during the 90 day evaluation period. The beads embolized predictably and effectively, resulting in areas devoid of contrast enhancement on CT imaging suggesting ischaemia-induced necrosis nearby the sites of occlusion. Instances of off target embolization were easily detected on imaging and confirmed pathologically. Histopathology revealed a classic foreign body response at 14 days, which resolved over time leading to fibrosis and eventual integration of the beads into the tissue, demonstrating excellent long-term tissue compatibility. PMID:27419364

  1. Evaluation of the soft tissue biocompatibility of MgCa0.8 and surgical steel 316L in vivo: a comparative study in rabbits

    PubMed Central

    2010-01-01

    Background Recent studies have shown the potential suitability of magnesium alloys as biodegradable implants. The aim of the present study was to compare the soft tissue biocompatibility of MgCa0.8 and commonly used surgical steel in vivo. Methods A biodegradable magnesium calcium alloy (MgCa0.8) and surgical steel (S316L), as a control, were investigated. Screws of identical geometrical conformation were implanted into the tibiae of 40 rabbits for a postoperative follow up of two, four, six and eight weeks. The tibialis cranialis muscle was in direct vicinity of the screw head and thus embedded in paraffin and histologically and immunohistochemically assessed. Haematoxylin and eosin staining was performed to identify macrophages, giant cells and heterophil granulocytes as well as the extent of tissue fibrosis and necrosis. Mouse anti-CD79α and rat anti-CD3 monoclonal primary antibodies were used for B- and T-lymphocyte detection. Evaluation of all sections was performed by applying a semi-quantitative score. Results Clinically, both implant materials were tolerated well. Histology revealed that a layer of fibrous tissue had formed between implant and overlying muscle in MgCa0.8 and S316L, which was demarcated by a layer of synoviocyte-like cells at its interface to the implant. In MgCa0.8 implants cavities were detected within the fibrous tissue, which were surrounded by the same kind of cell type. The thickness of the fibrous layer and the amount of tissue necrosis and cellular infiltrations gradually decreased in S316L. In contrast, a decrease could only be noted in the first weeks of implantation in MgCa0.8, whereas parameters were increasing again at the end of the observation period. B-lymphocytes were found more often in MgCa0.8 indicating humoral immunity and the presence of soluble antigens. Conversely, S316L displayed a higher quantity of T-lymphocytes. Conclusions Moderate inflammation was detected in both implant materials and resolved to a minimum

  2. Suture pullout strength and in vitro fibroblast and RAW 264.7 monocyte biocompatibility of genipin crosslinked nanofibrous chitosan mats for guided tissue regeneration.

    PubMed

    Norowski, P A; Mishra, S; Adatrow, P C; Haggard, W O; Bumgardner, J D

    2012-11-01

    Guided tissue regeneration (GTR) is a surgical technique used to direct the formation of bone in the graft space by protecting it with a barrier membrane used to exclude soft tissues during healing. Chitosan has been advocated for GTR applications because of its biocompatibility, degradability, wound healing, and osteogenic properties. In this study, electrospun chitosan membranes, crosslinked with 5 mM or 10 mM geinipin, a natural crosslinker extracted from the gardenia plant, were evaluated for suture pullout strength, crystallinity, and cytocompatibility with normal human dermal fibroblast and TIB 71™ RAW 264.7 monocyte cells. Ultimate suture pullout strength was significantly lower (51-67%) than that of commercially available collagen membranes. Crystallinity of the electrospun chitosan mats decreased upon crosslinking by 14-17% (p = 0.013). The molecular weight of the chitosan polymer was decreased by 75% during the electrospinning process. Uncrosslinked and genipin-crosslinked chitosan mats were cytocompatible and supported fibroblast cell proliferation for 9 days. Uncrosslinked and genipin-crosslinked membranes did not activate monocytes to produce nitric oxide (NO) in vitro in the absence of lipopolysaccharide (LPS). Finally, chitosan membranes inhibited LPS-induced NO production of RAW 264.7 cells by 59-67% as compared to tissue culture plastic and collagen membrane. Improvements are needed in the tear strength of electrospun chitosan membranes for clinical application. PMID:22696151

  3. Biocompatible Silk Noil-Based Three-Dimensional Carded-Needled Nonwoven Scaffolds Guide the Engineering of Novel Skin Connective Tissue.

    PubMed

    Chiarini, Anna; Freddi, Giuliano; Liu, Daisong; Armato, Ubaldo; Dal Prà, Ilaria

    2016-08-01

    Retracting hypertrophic scars resulting from healed burn wounds heavily impact on the patients' life quality. Biomaterial scaffolds guiding burned-out skin regeneration could suppress or lessen scar retraction. Here we report a novel silk noil-based three-dimensional (3D) nonwoven scaffold produced by carding and needling with no formic acid exposure, which might improve burn healing. Once wetted, it displays human skin-like physical features and a high biocompatibility. Human keratinocyte-like cervical carcinoma C4-I cells seeded onto the carded-needled nonwovens in vitro quickly adhered to them, grew, and actively metabolized glutamine releasing lactate. As on plastic, they released no proinflammatory IL-1β, although secreting tumor necrosis factor-alpha, an inducer of the autocrine mitogen amphiregulin in such cells. Once grafted into interscapular subcutaneous tissue of mice, carded-needled nonwovens guided the afresh assembly of a connective tissue enveloping the fibroin microfibers and filling the interposed voids within 3 months. Fibroblasts and a few poly- or mononucleated macrophages populated the engineered tissue. Besides, its extracellular matrix contained thin sparse collagen fibrils and a newly formed vascular network whose endothelin-1-expressing endothelial cells grew first on the fibroin microfibrils and later expanded into the intervening matrix. Remarkably, no infiltrates of inflammatory leukocytes and no packed collagen fibers bundles among fibroin microfibers, no fibrous capsules at the grafts periphery, and hence no foreign body response was obtained at the end of 3 months of observation. Therefore, we posit that silk noil-based 3D carded-needled nonwoven scaffolds are tools for translational medicine studies as they could guide connective tissue regeneration at deep burn wounds averting scar retraction with good functional results. PMID:27411949

  4. Translating textiles to tissue engineering: Creation and evaluation of microporous, biocompatible, degradable scaffolds using industry relevant manufacturing approaches and human adipose derived stem cells.

    PubMed

    Haslauer, Carla M; Avery, Matthew R; Pourdeyhimi, Behnam; Loboa, Elizabeth G

    2015-07-01

    Polymeric scaffolds have emerged as a means of generating three-dimensional tissues, such as for the treatment of bone injuries and nonunions. In this study, a fibrous scaffold was designed using the biocompatible, degradable polymer poly-lactic acid in combination with a water dispersible sacrificial polymer, EastONE. Fibers were generated via industry relevant, facile scale-up melt-spinning techniques with an islands-in-the-sea geometry. Following removal of EastONE, a highly porous fiber remained possessing 12 longitudinal channels and pores throughout all internal and external fiber walls. Weight loss and surface area characterization confirmed the generation of highly porous fibers as observed via focused ion beam/scanning electron microscopy. Porous fibers were then knit into a three-dimensional scaffold and seeded with human adipose-derived stem cells (hASC). Confocal microscopy images confirmed hASC attachment to the fiber walls and proliferation throughout the knit structure. Quantification of cell-mediated calcium accretion following culture in osteogenic differentiation medium confirmed hASC differentiation throughout the porous constructs. These results suggest incorporation of a sacrificial polymer within islands-in-the-sea fibers generates a highly porous scaffold capable of supporting stem cell viability and differentiation with the potential to generate large three-dimensional constructs for bone regeneration and/or other tissue engineering applications. PMID:25229198

  5. Translating Textiles to Tissue Engineering: Creation and Evaluation of Microporous, Biocompatible, Degradable Scaffolds Using Industry Relevant Manufacturing Approaches and Human Adipose Derived Stem Cells

    PubMed Central

    Haslauer, Carla M.; Avery, Matthew R.; Pourdeyhimi, Behnam; Loboa, Elizabeth G.

    2014-01-01

    Polymeric scaffolds have emerged as a means of generating three-dimensional tissues, such as for the treatment of bone injuries and non-unions. In this study, a fibrous scaffold was designed using the biocompatible, degradable polymer poly-lactic acid in combination with a water dispersible sacrificial polymer, EastONE. Fibers were generated via industry relevant, facile scale-up melt-spinning techniques with an islands-in-the-sea geometry. Following removal of EastONE, a highly porous fiber remained possessing 12 longitudinal channels and pores throughout all internal and external fiber walls. Weight loss and surface area characterization confirmed the generation of highly porous fibers as observed via focused ion beam/scanning electron microscopy. Porous fibers were then knit into a three-dimensional scaffold and seeded with human adipose-derived stem cells (hASC). Confocal microscopy images confirmed hASC attachment to the fiber walls and proliferation throughout the knit structure. Quantification of cell-mediated calcium accretion following culture in osteogenic differentiation medium confirmed hASC differentiation throughout the porous constructs. These results suggest incorporation of a sacrificial polymer within islands-in-the-sea fibers generates a highly porous scaffold capable of supporting stem cell viability and differentiation with the potential to generate large three-dimensional constructs for bone regeneration and/or other tissue engineering applications. PMID:25229198

  6. Electrical stimulation using conductive polymer polypyrrole promotes differentiation of human neural stem cells: a biocompatible platform for translational neural tissue engineering.

    PubMed

    Stewart, Elise; Kobayashi, Nao R; Higgins, Michael J; Quigley, Anita F; Jamali, Sina; Moulton, Simon E; Kapsa, Robert M I; Wallace, Gordon G; Crook, Jeremy M

    2015-04-01

    Conductive polymers (CPs) are organic materials that hold great promise for biomedicine. Potential applications include in vitro or implantable electrodes for excitable cell recording and stimulation and conductive scaffolds for cell support and tissue engineering. In this study, we demonstrate the utility of electroactive CP polypyrrole (PPy) containing the anionic dopant dodecylbenzenesulfonate (DBS) to differentiate novel clinically relevant human neural stem cells (hNSCs). Electrical stimulation of PPy(DBS) induced hNSCs to predominantly β-III Tubulin (Tuj1) expressing neurons, with lower induction of glial fibrillary acidic protein (GFAP) expressing glial cells. In addition, stimulated cultures comprised nodes or clusters of neurons with longer neurites and greater branching than unstimulated cultures. Cell clusters showed a similar spatial distribution to regions of higher conductivity on the film surface. Our findings support the use of electrical stimulation to promote neuronal induction and the biocompatibility of PPy(DBS) with hNSCs and opens up the possibility of identifying novel mechanisms of fate determination of differentiating human stem cells for advanced in vitro modeling, translational drug discovery, and regenerative medicine. PMID:25296166

  7. Chemical Synthesis, Characterization, and Biocompatibility Study of Hydroxyapatite/Chitosan Phosphate Nanocomposite for Bone Tissue Engineering Applications

    PubMed Central

    Pramanik, Nabakumar; Mishra, Debasish; Banerjee, Indranil; Maiti, Tapas Kumar; Bhargava, Parag; Pramanik, Panchanan

    2009-01-01

    A novel bioanalogue hydroxyapatite (HAp)/chitosan phosphate (CSP) nanocomposite has been synthesized by a solution-based chemical methodology with varying HAp contents from 10 to 60% (w/w). The interfacial bonding interaction between HAp and CSP has been investigated through Fourier transform infrared absorption spectra (FTIR) and x-ray diffraction (XRD). The surface morphology of the composite and the homogeneous dispersion of nanoparticles in the polymer matrix have been investigated through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The mechanical properties of the composite are found to be improved significantly with increase in nanoparticle contents. Cytotoxicity test using murine L929 fibroblast confirms that the nanocomposite is cytocompatible. Primary murine osteoblast cell culture study proves that the nanocomposite is osteocompatible and highly in vitro osteogenic. The use of CSP promotes the homogeneous distribution of particles in the polymer matrix through its pendant phosphate groups along with particle-polymer interfacial interactions. The prepared HAp/CSP nanocomposite with uniform microstructure may be used in bone tissue engineering applications. PMID:20130797

  8. In Vitro and In Vivo Evaluation of Self-Mineralization and Biocompatibility of Injectable, Dual-Gelling Hydrogels for Bone Tissue Engineering

    PubMed Central

    Spicer, Patrick P.; Watson, Brendan M.; Tzouanas, Stephanie N.; Roh, Terrence T.; Mikos, Antonios G.

    2015-01-01

    In this study, we investigated the mineralization capacity and biocompatibility of injectable, dual-gelling hydrogels in a rat cranial defect as a function of hydrogel hydrophobicity from either the copolymerization of a hydrolyzable lactone ring or the hydrogel polymer content. The hydrogel system comprised a poly(N-isopropylacrylamide)-based thermogelling macromer (TGM) and a polyamidoamine crosslinker. The thermogelling macromer was copolymerized with (TGM/DBA) or without (TGM) a dimethyl-γ-butyrolactone acrylate (DBA)-containing lactone ring that modulated the lower critical solution temperature and thus, the hydrogel hydrophobicity, over time. Three hydrogel groups were examined: (1) 15 wt% TGM, (2) 15 wt% TGM/DBA, and (3) 20 wt% TGM/DBA. The hydrogels were implanted within an 8 mm critical size rat cranial defect for 4 and 12 weeks. Implants were harvested at each timepoint and analyzed for bone formation, hydrogel mineralization and tissue response using microcomputed tomography (microCT). Histology and fibrous capsule scoring showed a light inflammatory response at 4 weeks that was mitigated by 12 weeks for all groups. MicroCT scoring and bone volume quantification demonstrated similar bone formation at 4 weeks that was significantly increased for the more hydrophobic hydrogel formulations - 15 wt% TGM and 20 wt% TGM/DBA - from 4 weeks to 12 weeks. A complementary in vitro acellular mineralization study revealed that the hydrogels exhibited calcium binding properties in the presence of serum-containing media, which was modulated by the hydrogel hydrophobicity. The tailored mineralization capacity of these injectable, dual-gelling hydrogels with hydrolysis-dependent hydrophobicity presents an exciting property for their use in bone tissue engineering applications. PMID:25483428

  9. Pegylation of Antimicrobial Peptides Maintains the Active Peptide Conformation, Model Membrane Interactions, and Antimicrobial Activity while Improving Lung Tissue Biocompatibility following Airway Delivery

    PubMed Central

    Morris, Christopher J.; Beck, Konrad; Fox, Marc A.; Ulaeto, David; Clark, Graeme C.

    2012-01-01

    Antimicrobial peptides (AMPs) have therapeutic potential, particularly for localized infections such as those of the lung. Here we show that airway administration of a pegylated AMP minimizes lung tissue toxicity while nevertheless maintaining antimicrobial activity. CaLL, a potent synthetic AMP (KWKLFKKIFKRIVQRIKDFLR) comprising fragments of LL-37 and cecropin A peptides, was N-terminally pegylated (PEG-CaLL). PEG-CaLL derivatives retained significant antimicrobial activity (50% inhibitory concentrations [IC50s] 2- to 3-fold higher than those of CaLL) against bacterial lung pathogens even in the presence of lung lining fluid. Circular dichroism and fluorescence spectroscopy confirmed that conformational changes associated with the binding of CaLL to model microbial membranes were not disrupted by pegylation. Pegylation of CaLL reduced AMP-elicited cell toxicity as measured using in vitro lung epithelial primary cell cultures. Further, in a fully intact ex vivo isolated perfused rat lung (IPRL) model, airway-administered PEG-CaLL did not result in disruption of the pulmonary epithelial barrier, whereas CaLL caused an immediate loss of membrane integrity leading to pulmonary edema. All AMPs (CaLL, PEG-CaLL, LL-37, cecropin A) delivered to the lung by airway administration showed limited (<3%) pulmonary absorption in the IPRL with extensive AMP accumulation in lung tissue itself, a characteristic anticipated to be beneficial for the treatment of pulmonary infections. We conclude that pegylation may present a means of improving the lung biocompatibility of AMPs designed for the treatment of pulmonary infections. PMID:22430978

  10. Biocompatibility of composite resins

    PubMed Central

    Mousavinasab, Sayed Mostafa

    2011-01-01

    Dental materials that are used in dentistry should be harmless to oral tissues, so they should not contain any leachable toxic and diffusible substances that can cause some side effects. Reports about probable biologic hazards, in relation to dental resins, have increased interest to this topic in dentists. The present paper reviews the articles published about biocompatibility of resin-restorative materials specially resin composites and monomers which are mainly based on Bis-GMA and concerns about their degradation and substances which may be segregated into oral cavity. PMID:23372592

  11. Method of making biocompatible electrodes

    DOEpatents

    Wollam, John S.

    1992-01-01

    A process of improving the sensing function of biocompatible electrodes and the product so made are disclosed. The process is designed to alter the surfaces of the electrodes at their tips to provide increased surface area and therefore decreased contact resistance at the electrode-tissue interface for increased sensitivity and essentially includes rendering the tips atomically clean by exposing them to bombardment by ions of an inert gas, depositing an adhesion layer on the cleaned tips, forming a hillocked layer on the adhesion layer by increasing the temperature of the tips, and applying a biocompatible coating on the hillocked layer. The resultant biocompatible electrode is characterized by improved sensitivity, minimum voltage requirement for organ stimulation and a longer battery life for the device in which it is employed.

  12. Electrospinning of Biocompatible Nanofibers

    NASA Astrophysics Data System (ADS)

    Coughlin, Andrew J.; Queen, Hailey A.; McCullen, Seth D.; Krause, Wendy E.

    2006-03-01

    Artificial scaffolds for growing cells can have a wide range of applications including wound coverings, supports in tissue cultures, drug delivery, and organ and tissue transplantation. Tissue engineering is a promising field which may resolve current problems with transplantation, such as rejection by the immune system and scarcity of donors. One approach to tissue engineering utilizes a biodegradable scaffold onto which cells are seeded and cultured, and ideally develop into functional tissue. The scaffold acts as an artificial extracellular matrix (ECM). Because a typical ECM contains collagen fibers with diameters of 50-500 nm, electrostatic spinning (electrospinning) was used to mimic the size and structure of these fibers. Electrospinning is a novel way of spinning a nonwoven web of fibers on the order of 100 nm, much like the web of collagen in an ECM. We are investigating the ability of several biocompatible polymers (e.g., chitosan and polyvinyl alcohol) to form defect-free nanofiber webs and are studying the influence of the zero shear rate viscosity, molecular weight, entanglement concentration, relaxation time, and solvent on the resulting fiber size and morphology.

  13. Biocompatibility of surgical implants

    NASA Technical Reports Server (NTRS)

    Kaelble, D. H.

    1979-01-01

    Method of selecting biocompatible materials for surgical implants uses fracture mechanic relationships and surface energies of candidate materials in presence of blood plasma. Technique has been used to characterize 190 materials by parameters that reflect their biocompatibility.

  14. THE BIOCOMPATIBILITY OF MESOPOROUS SILICATES

    PubMed Central

    Hudson, Sarah; Padera, Robert F.; Langer, Robert; Kohane, Daniel S.

    2008-01-01

    Micro- and nano- mesoporous silicate particles are considered potential drug delivery systems because of their ordered pore structures, large surface areas and the ease with which they can be chemically modified. However, few cytotoxicity or biocompatibility studies have been reported, especially when silicates are administered in the quantities necessary to deliver low-potency drugs. The biocompatibility of mesoporous silicates of particle sizes ~ 150 nm, ~ 800 nm and ~ 4 µm and pore sizes of 3 nm, 7 nm and 16 nm respectively are examined here. In vitro, mesoporous silicates showed a significant degree of toxicity at high concentrations with mesothelial cells. Following subcutaneous injection of silicates in rats, the amount of residual material decreased progressively over three months, with good biocompatibility on histology at all time points. In contrast, intra peritoneal and intra venous injections in mice resulted in death or euthanasia. No toxicity was seen with subcutaneous injection of the same particles in mice. Microscopic analysis of the lung tissue of the mice indicates that death may be due to thrombosis. Although local tissue reaction to mesoporous silicates was benign, they caused severe systemic toxicity. This toxicity could be mitigated by modification of the materials. PMID:18675454

  15. Taking a deep look: modern microscopy technologies to optimize the design and functionality of biocompatible scaffolds for tissue engineering in regenerative medicine

    PubMed Central

    Vielreicher, M.; Schürmann, S.; Detsch, R.; Schmidt, M. A.; Buttgereit, A.; Boccaccini, A.; Friedrich, O.

    2013-01-01

    This review focuses on modern nonlinear optical microscopy (NLOM) methods that are increasingly being used in the field of tissue engineering (TE) to image tissue non-invasively and without labelling in depths unreached by conventional microscopy techniques. With NLOM techniques, biomaterial matrices, cultured cells and their produced extracellular matrix may be visualized with high resolution. After introducing classical imaging methodologies such as µCT, MRI, optical coherence tomography, electron microscopy and conventional microscopy two-photon fluorescence (2-PF) and second harmonic generation (SHG) imaging are described in detail (principle, power, limitations) together with their most widely used TE applications. Besides our own cell encapsulation, cell printing and collagen scaffolding systems and their NLOM imaging the most current research articles will be reviewed. These cover imaging of autofluorescence and fluorescence-labelled tissue and biomaterial structures, SHG-based quantitative morphometry of collagen I and other proteins, imaging of vascularization and online monitoring techniques in TE. Finally, some insight is given into state-of-the-art three-photon-based imaging methods (e.g. coherent anti-Stokes Raman scattering, third harmonic generation). This review provides an overview of the powerful and constantly evolving field of multiphoton microscopy, which is a powerful and indispensable tool for the development of artificial tissues in regenerative medicine and which is likely to gain importance also as a means for general diagnostic medical imaging. PMID:23864499

  16. Biocompatible silk step-index optical waveguides

    PubMed Central

    Applegate, Matthew B.; Perotto, Giovanni; Kaplan, David L.; Omenetto, Fiorenzo G.

    2015-01-01

    Biocompatible optical waveguides were constructed entirely of silk fibroin. A silk film (n=1.54) was encapsulated within a silk hydrogel (n=1.34) to form a robust and biocompatible waveguide. Such waveguides were made using only biologically and environmentally friendly materials without the use of harsh solvents. Light was coupled into the silk waveguides by direct incorporation of a glass optical fiber. These waveguides are extremely flexible, and strong enough to survive handling and manipulation. Cutback measurements showed propagation losses of approximately 2 dB/cm. The silk waveguides were found to be capable of guiding light through biological tissue. PMID:26600988

  17. Biocompatibility of Titanium

    NASA Astrophysics Data System (ADS)

    Namavar, Fereydoon; Sabirianov, Renat; Marton, Denes; Rubinstein, Alexander; Garvin, Kevin

    2012-02-01

    Titanium is the material of choice for orthopaedic applications because of its known biocompatibility. In order to enhance osteogenic properties of the Ti implants, it is necessary to understand the origin of its biocompatibility. We addresses the origin of Ti biocompatibility through (1) theoretical modeling, (2) the precise determination of Ti surface chemistry by X-ray photoelectron spectroscopy (XPS), (3) and the study of fibronectin adsorption as a function of Ti (near) surface chemistry by Enzyme-linked immunosorbent assay (ELISA). We compare the protein adsorption on Ti with the native oxide layer and the one coated by TiO2 in anatase phase using ion beam assisted deposition (IBAD). We show that the thin native sub-stoichiometric titanium oxide layer is crucial for biocompatibility of Ti surface. This is due to the enhancement of the non-specific adsorption of proteins which mediate cell adhesion. Improving the surface oxide quality, i.e. fabricating stoichiometric TiO2 (using IBAD) as well as nanoengineering the surface topology that matches its dimensions to that of adhesive proteins, is crucial for increased protein adsorption and, as a result, further increases biocompatibility of Ti implant materials.

  18. Application of the lithium and magnesium initiators for the synthesis of glycolide, lactide, and epsilon-caprolactone copolymers biocompatible with brain tissue.

    PubMed

    Dobrzyński, Piotr; Kasperczyk, Janusz; Jelonek, Katarzyna; Ryba, Mirosław; Walski, Michał; Bero, Maciej

    2006-12-15

    The subject of this work is new method of the synthesis of biodegradable copolymers compatible with brain tissue. Copolymerization of glycolide with lactide was conducted in solution or in bulk in the presence of LiBu, LiAcac, MgBu(2), Mg(acac)(2) as initiators. In all cases, copolymers with molecular weight of 20000-40000 were obtained, which enables to use them as drug carriers. During the reactions of copolymer chain growth, the intermolecular transesterification occurs, changing the distribution of comonomeric units in copolymer chain. Magnesium initiators showed a lower contribution to transesterification in comparison with lithium and calcium compounds. The copolymerization of glycolide with epsilon-caprolactone using magnesium compounds as initiators was also described. The random glycolide/epsilon-caprolactone copolymer (10/90) obtained with MgBu(2) was used in in vivo study in the forms of microspheres and foils. Complete degradation of microspheres during 6 weeks was observed after the implantation to brain tissue. All implanted copolymers are compatible with brain tissue. PMID:16886217

  19. Biocompatibility of plasma nanostructured biopolymers

    NASA Astrophysics Data System (ADS)

    Slepičková Kasálková, N.; Slepička, P.; Bačáková, L.; Sajdl, P.; Švorčík, V.

    2013-07-01

    Many areas of medicine such as tissue engineering requires not only mastery of modification techniques but also thorough knowledge of the interaction of cells with solid state substrates. Plasma treatment can be used to effective modification, nanostructuring and therefore can significantly change properties of materials. In this work the biocompatibility of the plasma nanostructured biopolymers substrates was studied. Changes in surface chemical structure were studied by X-ray photoelectron spectroscopy (XPS). The morphology pristine and modified samples were determined using atomic force microscopy (AFM). The surface wettability was determined by goniometry from contact angle. Biocompatibility was determined by in vitro tests, the rat vascular smooth muscle cells (VSMCs) were cultivated on the pristine and plasma modified biopolymer substrates. Their adhesion, proliferation, spreading and homogeneous distribution on polymers was monitored. It was found that the plasma treatment leads to rapid decrease of contact angle for all samples. Contact angle decreased with increasing time of modification. XPS measurements showed that plasma treatment leads to changes in ratio of polar and non-polar groups. Plasma modification was accompanied by a change of surface morphology. Biological tests found that plasma treatment have positive effect on cells adhesion and proliferation cells and affects the size of cell's adhesion area. Changes in plasma power or in exposure time influences the number of adhered and proliferated cells and their distribution on biopolymer surface.

  20. Bioglass: A novel biocompatible innovation

    PubMed Central

    Krishnan, Vidya; Lakshmi, T.

    2013-01-01

    Advancement of materials technology has been immense, especially in the past 30 years. Ceramics has not been new to dentistry. Porcelain crowns, silica fillers in composite resins, and glass ionomer cements have already been proved to be successful. Materials used in the replacement of tissues have come a long way from being inert, to compatible, and now regenerative. When hydroxyapatite was believed to be the best biocompatible replacement material, Larry Hench developed a material using silica (glass) as the host material, incorporated with calcium and phosphorous to fuse broken bones. This material mimics bone material and stimulates the regrowth of new bone material. Thus, due to its biocompatibility and osteogenic capacity it came to be known as “bioactive glass-bioglass.” It is now encompassed, along with synthetic hydroxyapatite, in the field of biomaterials science known as “bioactive ceramics.” The aim of this article is to give a bird's-eye view, of the various uses in dentistry, of this novel, miracle material which can bond, induce osteogenesis, and also regenerate bone. PMID:23833747

  1. Biomimetic scaffolds based on hydroxyapatite nanorod/poly(D,L) lactic acid with their corresponding apatite-forming capability and biocompatibility for bone-tissue engineering.

    PubMed

    Nga, Nguyen Kim; Hoai, Tran Thanh; Viet, Pham Hung

    2015-04-01

    This study presents a facile synthesis of biomimetic hydroxyapatite nanorod/poly(D,L) lactic acid (HAp/PDLLA) scaffolds with the use of solvent casting combined with a salt-leaching technique for bone-tissue engineering. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy were used to observe the morphologies, pore structures of synthesized scaffolds, interactions between hydroxyapatite nanorods and poly(D,L) lactic acid, as well as the compositions of the scaffolds, respectively. Porosity of the scaffolds was determined using the liquid substitution method. Moreover, the apatite-forming capability of the scaffolds was evaluated through simulated body fluid (SBF) incubation tests, whereas the viability, attachment, and distribution of human osteoblast cells (MG 63 cell line) on the scaffolds were determined through alamarBlue assay and confocal laser microscopy after nuclear staining with 4',6-diamidino-2-phenylindole and actin filaments of a cytoskeleton with Oregon Green 488 phalloidin. Results showed that hydroxyapatite nanorod/poly(D,L) lactic acid scaffolds that mimic the structure of natural bone were successfully produced. These scaffolds possessed macropore networks with high porosity (80-84%) and mean pore sizes ranging 117-183 μm. These scaffolds demonstrated excellent apatite-forming capabilities. The rapid formation of bone-like apatites with flower-like morphology was observed after 7 days of incubation in SBFs. The scaffolds that had a high percentage (30 wt.%) of hydroxyapatite demonstrated better cell adhesion, proliferation, and distribution than those with low percentages of hydroxyapatite as the days of culture increased. This work presented an efficient route for developing biomimetic composite scaffolds, which have potential applications in bone-tissue engineering. PMID:25791418

  2. Sticking to the story: outstanding challenges in gecko-inspired adhesives.

    PubMed

    Niewiarowski, Peter H; Stark, Alyssa Y; Dhinojwala, Ali

    2016-04-01

    The natural clinging ability of geckos has inspired hundreds of studies seeking design principles that could be applied to creating synthetic adhesives with the same performance capabilities as the gecko: adhesives that use no glue, are self-cleaning and reusable, and are insensitive to a wide range of surface chemistries and roughness. Important progress has been made, and the basic mechanics of how 'hairy' adhesives work have been faithfully reproduced, advancing theory in surface science and portending diverse practical applications. However, after 15 years, no synthetic mimic can yet perform as well as a gecko and simultaneously meet of all the criteria listed above. Moreover, processes for the production of inexpensive and scalable products are still not clearly in view. Here, we discuss our perspective on some of the gaps in understanding that still remain; these gaps in our knowledge should stimulate us to turn to deeper study of the way in which free-ranging geckos stick to the variety of surfaces found in their natural environments and to a more complete analysis of the materials composing the gecko toe pads. PMID:27030772

  3. Monitoring the Contact Stress Distribution of Gecko-Inspired Adhesives Using Mechano-Sensitive Surface Coatings.

    PubMed

    Neubauer, Jens W; Xue, Longjian; Erath, Johann; Drotlef, Dirk-M; Campo, Aránzazu Del; Fery, Andreas

    2016-07-20

    The contact geometry of microstructured adhesive surfaces is of high relevance for adhesion enhancement. Theoretical considerations indicate that the stress distribution in the contact zone is crucial for the detachment mechanism, but direct experimental evidence is missing so far. In this work, we propose a method that allows, for the first time, the detection of local stresses at the contact area of biomimetic adhesive microstructures during contact formation, compression and detachment. We use a mechano-sensitive polymeric layer, which turns mechanical stresses into changes of fluorescence intensity. The biomimetic surface is brought into contact with this layer in a well-defined fashion using a microcontact printer, while the contact area is monitored with fluorescence microscopy in situ. Thus, changes in stress distribution across the contact area during compression and pull-off can be visualized with a lateral resolution of 1 μm. We apply this method to study the enhanced adhesive performance of T-shaped micropillars, compared to flat punch microstructures. We find significant differences in the stress distribution of the both differing contact geometries during pull-off. In particular, we find direct evidence for the suppression of crack nucleation at the edge of T-shaped pillars, which confirms theoretical models for the superior adhesive properties of these structures. PMID:27327111

  4. Adhesion mechanism of a gecko-inspired oblique structure with an adhesive tip for asymmetric detachment

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Yu; Takahashi, Kunio; Sato, Chiaki

    2015-12-01

    An adhesion model of an oblique structure with an adhesive tip is proposed by considering a limiting stress for adhesion to describe the detachment mechanism of gecko foot hairs. When a force is applied to the root of the oblique structure, normal and shear stresses are generated at contact and the adhesive tip is detached from the surface when reaching the limiting stress. An adhesion criterion that considers both the normal and shear stresses is introduced, and the asymmetric detachment of the oblique structure is theoretically investigated. In addition, oblique beam array structures are manufactured, and an inclination effect of the structure on the asymmetric detachment is experimentally verified.

  5. Effect of leaning angle of gecko-inspired slanted polymer nanohairs on dry adhesion

    NASA Astrophysics Data System (ADS)

    Jeong, Hoon Eui; Lee, Jin-Kwan; Kwak, Moon Kyu; Moon, Sang Heup; Suh, Kahp Yang

    2010-01-01

    We present analysis of adhesion properties of angled polymer nanohairs with a wide range of leaning angles from 0° to 45° and ultraviolet (UV)-curable polyurethane acrylate (PUA) materials of two different elastic moduli (19.8 and 320 MPa). It is demonstrated that shear adhesion and adhesion hysteresis can be greatly enhanced by increasing the leaning angle of nanohairs both for soft and hard materials due to increased contact area and reduced structural stiffness.

  6. Friction and adhesion of gecko-inspired PDMS flaps on rough surfaces.

    PubMed

    Yu, Jing; Chary, Sathya; Das, Saurabh; Tamelier, John; Turner, Kimberly L; Israelachvili, Jacob N

    2012-08-01

    Geckos have developed a unique hierarchical structure to maintain climbing ability on surfaces with different roughness, one of the extremely important parameters that affect the friction and adhesion forces between two surfaces. Although much attention has been paid on fabricating various structures that mimic the hierarchical structure of a gecko foot, yet no systematic effort, in experiment or theory, has been made to quantify the effect of surface roughness on the performance of the fabricated structures that mimic the hierarchical structure of geckos. Using a modified surface forces apparatus (SFA), we measured the adhesion and friction forces between microfabricated tilted PDMS flaps and optically smooth SiO(2) and rough SiO(2) surfaces created by plasma etching. Anisotropic adhesion and friction forces were measured when sliding the top glass surface along (+y) and against (-y) the tilted direction of the flaps. Increasing the surface roughness first increased the adhesion and friction forces measured between the flaps and the rough surface due to topological matching of the two surfaces but then led to a rapid decrease in both of these forces. Our results demonstrate that the surface roughness significantly affects the performance of gecko mimetic adhesives and that different surface textures can either increase or decrease the adhesion and friction forces of the fabricated adhesives. PMID:22779923

  7. Gecko-inspired surfaces: a path to strong and reversible dry adhesives.

    PubMed

    Boesel, Luciano F; Greiner, Christian; Arzt, Eduard; del Campo, Aránzazu

    2010-05-18

    The amazing adhesion of gecko pads to almost any kind of surfaces has inspired a very active research direction over the last decade: the investigation of how geckos achieve this feat and how this knowledge can be turned into new strategies to reversibly join surfaces. This article reviews the fabrication approaches used so far for the creation of micro- and nanostructured fibrillar surfaces with adhesive properties. In the light of the pertinent contact mechanics, the adhesive properties are presented and discussed. The decisive design parameters are fiber radius and aspect ratio, tilt angle, hierarchical arrangement and the effect of the backing layer. Also first responsive systems that allow thermal switching between nonadhesive and adhesive states are described. These structures show a high potential of application, providing the remaining issues of robustness, reliability, and large-area manufacture can be solved. PMID:20349430

  8. Biocompatibility and osteogenic properties of porous tantalum

    PubMed Central

    WANG, QIAN; ZHANG, HUI; LI, QIJIA; YE, LEI; GAN, HONGQUAN; LIU, YINGJIE; WANG, HUI; WANG, ZHIQIANG

    2015-01-01

    Porous tantalum has been reported to be a promising material for use in bone tissue engineering. In the present study, the biocompatibility and osteogenic properties of porous tantalum were studied in vitro and in vivo. The morphology of porous tantalum was observed using scanning electron microscopy (SEM). Osteoblasts were cultured with porous tantalum, and cell morphology, adhesion and proliferation were investigated using optical microscopy and SEM. In addition, porous tantalum rods were implanted in rabbits, and osteogenesis was observed using laser scanning confocal microscopy and hard tissue slice examination. The osteoblasts were observed to proliferate over time and adhere to the tantalum surface and pore walls, exhibiting a variety of shapes and intercellular connections. The porous tantalum rod connected tightly with the host bone. At weeks 2 and 4 following implantation, new bone and small blood vessels were observed at the tantalum-host bone interface and pores. At week 10 after the porous tantalum implantation, new bone tissue was observed at the tantalum-host bone interface and pores. By week 12, the tantalum-host bone interface and pores were covered with new bone tissue and the bone trabeculae had matured and connected directly with the materials. Therefore, the results of the present study indicate that porous tantalum is non-toxic, biocompatible and a promising material for use in bone tissue engineering applications. PMID:25667628

  9. There is no such thing as a biocompatible material.

    PubMed

    Williams, David F

    2014-12-01

    This Leading Opinion Paper discusses a very important matter concerning the use of a single word in biomaterials science. This might be considered as being solely concerned with semantics, but it has implications for the scientific rationale for biomaterials selection and the understanding of their performance. That word is the adjective 'biocompatible', which is often used to characterize a material property. It is argued here that biocompatibility is a perfectly acceptable term, but that it subsumes a variety of mechanisms of interaction between biomaterials and tissues or tissue components and can only be considered in the context of the characteristics of both the material and the biological host within which it placed. De facto it is a property of a system and not of a material. It follows that there can be no such thing as a biocompatible material. It is further argued that in those situations where it is considered important, or necessary, to use a descriptor of biocompatibility, as in a scientific paper, a regulatory submission or in a legal argument, the phrase 'intrinsically biocompatible system' would be the most appropriate. The rationale for this linguistic restraint is that far too often it has been assumed that some materials are 'universally biocompatible' on the basis of acceptable clinical performance in one situation, only for entirely unacceptable performance to ensue in quite different clinical circumstances. PMID:25263686

  10. [Biocompatibility of dental amalgam].

    PubMed

    Missias, P

    1990-10-01

    The purpose of the present review was to present a detailed description of those current scientific results and opinions relative to the biocompatibility of dental amalgam. The first section of the percent review to the pulpar reactions caused by amalgam fillings, especially when no protective base has been used, while the second part concerns itself with the biocompatibility of the dental amalgam per se. Specifically, reference is made to: a) the adverse reactions due to amalgam fillings both on the patient's physiological system and on the dentist's employing the material under consideration. b) those investigation results bearing a relation on the amount of mercury liberated during the amalgam filling procedures, i.e., mixing, condensation, finishing and polishing and/or removal of old amalgam fillings. c) Liberation of mercury, as well as metallic ions in the patients mouth cavity during chewing and/or during the process of intrabuccal galvanization and corrosion, and d) on the amount of mercury traced in the blood and urine of the patient following amalgam fillings. No conclusive evidence on any adverse reactions on the patient's health, attributable to the liberation of mercury from amalgam fillings, could be presented by the scientific investigations under consideration. Moreover, the number of cases reported on toxic reactions due to dental amalgam is negligible compared to the immense number of amalgam fillings performed in practice. It merits mentioning in this connection, however, the fact that the total amount of mercury attained by the patient from any other source, in conjunction with that liberated from amalgam fillings, could by all means contribute to a number of toxic reactions on the patient's health in general. Conclusively, one could state without reservations, that dental amalgam fillings per se are by and large free of toxic reactions on the patient, based on current scientific observations. Mentioning is finally made on several simple but

  11. Synthetic cornea: biocompatibility and optics

    NASA Astrophysics Data System (ADS)

    Parel, Jean-Marie A.; Kaminski, Stefan; Fernandez, Viviana; Alfonso, E.; Lamar, Peggy; Lacombe, Emmanuel; Duchesne, Bernard; Dubovy, Sander; Manns, Fabrice; Rol, Pascal O.

    2002-06-01

    Purpose. Experimentally find a method to provide a safe surgical technique and an inexpensive and long lasting mesoplant for the restoration of vision in patients with bilateral corneal blindness due to ocular surface and stromal diseases. Methods. Identify the least invasive and the safest surgical technique for synthetic cornea implantation. Identify the most compatible biomaterials and the optimal shape a synthetic cornea must have to last a long time when implanted in vivo. Results. Penetrating procedures were deemed too invasive, time consuming, difficult and prone to long term complications. Therefore a non-penetrating delamination technique with central trephination was developed to preserve the integrity of Descemet's membrane and the anterior segment. Even though this approach limits the number of indications, it is acceptable since the majority of patients only have opacities in the stroma. The prosthesis was designed to fit in the removed tissue plane with its skirt fitted under the delaminated stroma. To improve retention, the trephination wall was made conical with the smallest opening on the anterior surface and a hat-shaped mesoplant was made to fit. The skirt was perforated in its perimeter to allow passage of nutrients and tissues ingrowths. To simplify the fabrication procedure, the haptic and optic were made of the same polymer. The intrastromal biocompatibility of several hydrogels was found superior to current clinically used PMMA and PTFE materials. Monobloc mesoplants made of 4 different materials were implanted in rabbits and followed weekly until extrusion occurred. Some remained optically clear allowing for fundus photography. Conclusions. Hydrogel synthetic corneas can be made to survive for periods longer than 1 year. ArF excimer laser photoablation studies are needed to determine the refractive correction potential of these mesoplants. A pilot FDA clinical trial is needed to assess the mesoplant efficacy and very long-term stability.

  12. Biocompatible nanoparticles and biopolyelectrolytes

    NASA Astrophysics Data System (ADS)

    Zribi, Olena

    The research presented in this manuscript encompasses a merger of two research directions: a study of aqueous nanoparticle colloids and a study of biological polyelectrolytes. The majority of biomedical applications of nanoparticles require stable aqueous colloids of nanoparticles as a starting point. A new one-step method of preparation of aqueous solutions of ultra-fine ferroelectric barium titanate nanoparticles was developed and generalized to the preparation of stable aqueous colloids of semiconductor nanoparticles. This high-energy ball milling technique is low cost, environmentally friendly, and allows for control of nanoparticle size by changing milling time. Aqueous colloids of BaTiO3 nanoparticles are stable over time, maintain ferroelectricity and can be used as second harmonic generating nanoprobes for biomedical imaging. Biopolyelectrolytes exhibit a variety of novel liquid-crystalline phases in aqueous solutions where their electrolytic nature is a driving force behind phase formation. We study medically relevant mixtures of F-actin, DNA and oppositely charged ions (such as multivalent salts and antibiotic drugs) and map out phase diagrams and laws that govern phase transitions. We combine these research directions in studies of the condensation behavior in aqueous solutions of biocompatible nanoparticles and biopolyelectrolytes.

  13. [Biocompatibility of peritoneal dialysis fluids].

    PubMed

    Boulanger, Eric; Moranne, Olivier; Wautier, Marie-Paule; Rougier, Jean-Phillipe; Ronco, Pierre; Pagniez, Dominique; Wautier, Jean-Luc

    2005-03-01

    Repeated and long-term exposure to conventional glucose-based peritoneal dialysis fluids (PDFs) with poor biocompatibility plays a central role in the pathogenesis of the functional and structural changes of the peritoneal membrane. We have used immortalized human peritoneal mesothelial cells in culture to assess in vitro the biocompatibility of PDFs. Low pH, high glucose concentration and heat sterilization represent major factors of low biocompatibility. Two recent groups of glucose derivatives have been described. Glucose degradation products (GDPs) are formed during heat sterilization (glycoxidation) and storage. GDPs can bind protein and form AGEs (Advanced Glycation End-products), which can also result from the binding of glucose to free NH2 residues of proteins (glycation). The physiological pH, and the separation of glucose during heat sterilization (low GDP content) in the most recent PDFs dramatically increase the biocompatibility. The choice of PD programs with high biocompatibility PDFs allows preserving the function of the peritoneal membrane. Improvement of PDF biocompatibility may limit the occurrence of chronic chemical peritonitis and may allow long-term PD treatment. PMID:16895663

  14. Biocompatibility of Textile Titanium Nickel Implants with Fibroblast Culture.

    PubMed

    Kokorev, O V; Khodorenko, V N; Anikeev, S G; Gunther, V E

    2015-05-01

    The parameters of biocompatibility of titanium nickel implants of different design with fibroblast culture are studied. Colonization of textile and mesh implants with fibroblasts and tissue development depend on the size of mesh cells and thread diameter. Titanium nickel implants of different constructions do not inhibit the growth of fibroblast culture. PMID:26028231

  15. Carbon Fiber Biocompatibility for Implants

    PubMed Central

    Petersen, Richard

    2016-01-01

    Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-reinforced composite stimulated osseointegration inside the tibia bone marrow measured as percent bone area (PBA) to a great extent when compared to the titanium-6-4 alloy at statistically significant levels. PBA increased significantly with the carbon-fiber composite over the titanium-6-4 alloy for distances from the implant surfaces of 0.1 mm at 77.7% vs. 19.3% (p < 10−8) and 0.8 mm at 41.6% vs. 19.5% (p < 10−4), respectively. The review focuses on carbon fiber properties that increased PBA for enhanced implant osseointegration. Carbon fibers acting as polymer coated electrically conducting micro-biocircuits appear to provide a biocompatible semi-antioxidant property to remove damaging electron free radicals from the surrounding implant surface. Further, carbon fibers by removing excess electrons produced from the cellular mitochondrial electron transport chain during periods of hypoxia perhaps stimulate bone cell recruitment by free-radical chemotactic influences. In addition, well-studied bioorganic cell actin carbon fiber growth would appear to interface in close contact with the carbon-fiber-reinforced composite implant. Resulting subsequent actin carbon fiber/implant carbon fiber contacts then could help in discharging the electron biological overloads through electrochemical gradients to lower negative charges and lower concentration. PMID:26966555

  16. Biocompatibility of Bacterial Cellulose Based Biomaterials

    PubMed Central

    Torres, Fernando G.; Commeaux, Solene; Troncoso, Omar P.

    2012-01-01

    Some bacteria can synthesize cellulose when they are cultivated under adequate conditions. These bacteria produce a mat of cellulose on the top of the culture medium, which is formed by a three-dimensional coherent network of pure cellulose nanofibers. Bacterial cellulose (BC) has been widely used in different fields, such as the paper industry, electronics and tissue engineering due to its remarkable mechanical properties, conformability and porosity. Nanocomposites based on BC have received much attention, because of the possibility of combining the good properties of BC with other materials for specific applications. BC nanocomposites can be processed either in a static or an agitated medium. The fabrication of BC nanocomposites in static media can be carried out while keeping the original mat structure obtained after the synthesis to form the final nanocomposite or by altering the culture media with other components. The present article reviews the issue of biocompatibility of BC and BC nanocomposites. Biomedical aspects, such as surface modification for improving cell adhesion, in vitro and in vivo studies are given along with details concerning the physics of network formation and the changes that occur in the cellulose networks due to the presence of a second phase. The relevance of biocompatibility studies for the development of BC-based materials in bone, skin and cardiovascular tissue engineering is also discussed. PMID:24955750

  17. Biocompatibility of polymethylmethacrylate resins used in dentistry.

    PubMed

    Gautam, Rupali; Singh, Raghuwar D; Sharma, Vinod P; Siddhartha, Ramashanker; Chand, Pooran; Kumar, Rakesh

    2012-07-01

    Biocompatibility or tissue compatibility describes the ability of a material to perform with an appropriate host response when applied as intended. Poly-methylmethacrylate (PMMA) based resins are most widely used resins in dentistry, especially in fabrication of dentures and orthodontic appliances. They are considered cytotoxic on account of leaching of various potential toxic substances, most common being residual monomer. Various in vitro and in vivo experiments and cell based studies conducted on acrylic based resins or their leached components have shown them to have cytotoxic effects. They can cause mucosal irritation and tissue sensitization. These studies are not only important to evaluate the long term clinical effect of these materials, but also help in further development of alternate resins. This article reviews information from scientific full articles, reviews, or abstracts published in dental literature, associated with biocompatibility of PMMA resins and it is leached out components. Published materials were searched in dental literature using general and specialist databases, like the PubMED database. PMID:22454327

  18. Ultraflexible organic amplifier with biocompatible gel electrodes.

    PubMed

    Sekitani, Tsuyoshi; Yokota, Tomoyuki; Kuribara, Kazunori; Kaltenbrunner, Martin; Fukushima, Takanori; Inoue, Yusuke; Sekino, Masaki; Isoyama, Takashi; Abe, Yusuke; Onodera, Hiroshi; Someya, Takao

    2016-01-01

    In vivo electronic monitoring systems are promising technology to obtain biosignals with high spatiotemporal resolution and sensitivity. Here we demonstrate the fabrication of a biocompatible highly conductive gel composite comprising multi-walled carbon nanotube-dispersed sheet with an aqueous hydrogel. This gel composite exhibits admittance of 100 mS cm(-2) and maintains high admittance even in a low-frequency range. On implantation into a living hypodermal tissue for 4 weeks, it showed a small foreign-body reaction compared with widely used metal electrodes. Capitalizing on the multi-functional gel composite, we fabricated an ultrathin and mechanically flexible organic active matrix amplifier on a 1.2-μm-thick polyethylene-naphthalate film to amplify (amplification factor: ∼200) weak biosignals. The composite was integrated to the amplifier to realize a direct lead epicardial electrocardiography that is easily spread over an uneven heart tissue. PMID:27125910

  19. Ultraflexible organic amplifier with biocompatible gel electrodes

    NASA Astrophysics Data System (ADS)

    Sekitani, Tsuyoshi; Yokota, Tomoyuki; Kuribara, Kazunori; Kaltenbrunner, Martin; Fukushima, Takanori; Inoue, Yusuke; Sekino, Masaki; Isoyama, Takashi; Abe, Yusuke; Onodera, Hiroshi; Someya, Takao

    2016-04-01

    In vivo electronic monitoring systems are promising technology to obtain biosignals with high spatiotemporal resolution and sensitivity. Here we demonstrate the fabrication of a biocompatible highly conductive gel composite comprising multi-walled carbon nanotube-dispersed sheet with an aqueous hydrogel. This gel composite exhibits admittance of 100 mS cm-2 and maintains high admittance even in a low-frequency range. On implantation into a living hypodermal tissue for 4 weeks, it showed a small foreign-body reaction compared with widely used metal electrodes. Capitalizing on the multi-functional gel composite, we fabricated an ultrathin and mechanically flexible organic active matrix amplifier on a 1.2-μm-thick polyethylene-naphthalate film to amplify (amplification factor: ~200) weak biosignals. The composite was integrated to the amplifier to realize a direct lead epicardial electrocardiography that is easily spread over an uneven heart tissue.

  20. Biocompatibility of root-end filling materials: recent update

    PubMed Central

    Gupta, Saurabh Kumar; Newaskar, Vilas

    2013-01-01

    The purpose of a root-end filling is to establish a seal between the root canal space and the periradicular tissues. As root-end filling materials come into contact with periradicular tissues, knowledge of the tissue response is crucial. Almost every available dental restorative material has been suggested as the root-end material of choice at a certain point in the past. This literature review on root-end filling materials will evaluate and comparatively analyse the biocompatibility and tissue response to these products, with primary focus on newly introduced materials. PMID:24010077

  1. Biocompatibility of root-end filling materials: recent update.

    PubMed

    Saxena, Payal; Gupta, Saurabh Kumar; Newaskar, Vilas

    2013-08-01

    The purpose of a root-end filling is to establish a seal between the root canal space and the periradicular tissues. As root-end filling materials come into contact with periradicular tissues, knowledge of the tissue response is crucial. Almost every available dental restorative material has been suggested as the root-end material of choice at a certain point in the past. This literature review on root-end filling materials will evaluate and comparatively analyse the biocompatibility and tissue response to these products, with primary focus on newly introduced materials. PMID:24010077

  2. The quantification of biocompatibility: toward a new definition

    NASA Astrophysics Data System (ADS)

    Ratner, Buddy

    2008-03-01

    Implantable medical devices, and the biomaterials that comprise them, form a 100B business worldwide. Medical devices save lives and/or improve the quality of life for millions. Tissue engineering also makes extensive use of biomaterials -- biomaterials are an enabling technology for tissue engineering. A central word to understanding the effectiveness of such materials and devices is biocompatibility. The word ``biocompatible'' is widely used in reference to biomaterials and medical devices and most everyone has some value understanding of its meaning. Many formal definitions have been proposed for this word, but it is still largely used in an imprecise manner. Four descriptions or definitions of biocompatibility will be reviewed: a widely adopted definition from a consensus conference, a surgeon's perspective on this word, the regulatory agency view and the factors that clearly influence biocompatibility. In this talk, the classical definition of biocompatibility will be contrasted to a newer definition embracing molecular concepts and the understanding of normal wound healing. The biological data on the in vivo healing responses of mammals to implants will be described. A strategy to improve the healing of biomaterials will be presented. It is based upon surface molecular engineering. First, non-specific protein adsorption must be inhibited. Strategies to achieve this design parameter will be presented. Then methods to deliver the specific protein signals will be addressed. Matricellular proteins such as osteopontin, thrombospondin 2 and SPARC will be introduced with an emphasis on exploiting the special reactivity of such proteins. A discussion of the influence of surface textures and porosities will also be presented. Finally a new scheme based upon macrophage phenotypic pathways will be proposed that may allow a quantitative measure of extent of biocompatibility.

  3. Biocompatible electrospun polymer blends for biomedical applications.

    PubMed

    Munj, Hrishikesh Ramesh; Nelson, M Tyler; Karandikar, Prathamesh Sadanand; Lannutti, John Joseph; Tomasko, David Lane

    2014-10-01

    Blends of natural and synthetic polymers have received considerable attention as biomaterials due to the potential to optimize both mechanical and bioactive properties. Electrospinning of biocompatible polymers is an efficient method producing biomimetic topographies suited to various applications. In the ultimate application, electrospun scaffolds must also incorporate drug/protein delivery for effective cell growth and tissue repair. This study explored the suitability of a ternary Polymethylmethacrylate-Polycaprolactone-gelatin blend in the preparation of electrospun scaffolds for biomedical applications. Tuning the blend composition allows control over scaffold mechanical properties and degradation rate. Significant improvements were observed in the mechanical properties of the blend compared with the individual components. In order to study drug delivery potential, triblends were impregnated with the model compound Rhodamine-B using sub/supercritical CO₂ infusion under benign conditions. Results show significantly distinct release profiles of the impregnated dye from the triblends. Specific factors such as porosity, degradation rate, stress relaxation, dye-polymer interactions, play key roles in impregnation and release. Each polymer component of the triblends shows distinct behavior during impregnation and release process. This affects the aforementioned factors and the release profiles of the dye. Careful control over blend composition and infusion conditions creates the flexibility needed to produce biocompatible electrospun scaffolds for a variety of biomedical applications. PMID:24604876

  4. BOP: biocompatible osteoconductive polymer: an experimental approach.

    PubMed

    Buron, F; Bourgois, R; Burny, F; Chaboteaux, C; d'Hemricourt, J; el Banna, S; Pasteels, J L; Sintzoff, S; Vienne, A

    1994-01-01

    BOP (biocompatible osteoconductive polymer) is a material proposed for osteosyntheses and for filling of bone defects in orthopaedics, neurosurgery and stomatology. It is a composite made of a copolymer of N-vinylpyrrolidone and methylmethacrylate, of polyamide-6 fibers and of calcium gluconate. The histological investigation includes the study of 30 intact rabbit femurs instrumented with a BOP rod, as well as the study of organs of the reticuloendothelial system. The currently available results show the absence of toxicity on hematopoietic tissue. Zones of osteoblastic activity surround the rods, coupled with an osteoclastic reaction which may result in the partial fragmentation of the polyamide fibers and its incorporation in the newly formed bone. We also observed the encapsulation of the material. The biomechanical approach investigated the mechanical properties of the material in bending and in shear. The radiological aspects of the investigation consisted of computerized axial tomography of the implanted femurs to measure density at the bone-implant interface. PMID:10150170

  5. Biocompatible 3D Matrix with Antimicrobial Properties.

    PubMed

    Ion, Alberto; Andronescu, Ecaterina; Rădulescu, Dragoș; Rădulescu, Marius; Iordache, Florin; Vasile, Bogdan Ștefan; Surdu, Adrian Vasile; Albu, Madalina Georgiana; Maniu, Horia; Chifiriuc, Mariana Carmen; Grumezescu, Alexandru Mihai; Holban, Alina Maria

    2016-01-01

    The aim of this study was to develop, characterize and assess the biological activity of a new regenerative 3D matrix with antimicrobial properties, based on collagen (COLL), hydroxyapatite (HAp), β-cyclodextrin (β-CD) and usnic acid (UA). The prepared 3D matrix was characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Microscopy (FT-IRM), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). In vitro qualitative and quantitative analyses performed on cultured diploid cells demonstrated that the 3D matrix is biocompatible, allowing the normal development and growth of MG-63 osteoblast-like cells and exhibited an antimicrobial effect, especially on the Staphylococcus aureus strain, explained by the particular higher inhibitory activity of usnic acid (UA) against Gram positive bacterial strains. Our data strongly recommend the obtained 3D matrix to be used as a successful alternative for the fabrication of three dimensional (3D) anti-infective regeneration matrix for bone tissue engineering. PMID:26805790

  6. CYTOTOXICITY AND BIOCOMPATIBILITY OF DIRECT AND INDIRECT PULP CAPPING MATERIALS

    PubMed Central

    Modena, Karin Cristina da Silva; Casas-Apayco, Leslie Caroll; Atta, Maria Teresa; Costa, Carlos Alberto de Souza; Hebling, Josimeri; Sipert, Carla Renata; Navarro, Maria Fidela de Lima; Santos, Carlos Ferreira

    2009-01-01

    There are several studies about the cytotoxic effects of dental materials in contact with the pulp tissue, such as calcium hydroxide (CH), adhesive systems, resin composite and glass ionomer cements. The aim of this review article was to summarize and discuss the cytotoxicity and biocompatibility of materials used for protection of the dentin-pulp complex, some components of resin composites and adhesive systems when placed in direct or indirect contact with the pulp tissue. A large number of dental materials present cytotoxic effects when applied close or directly to the pulp, and the only material that seems to stimulate early pulp repair and dentin hard tissue barrier formation is CH. PMID:20027424

  7. Biocompatibility of Ti-alloys for long-term implantation.

    PubMed

    Abdel-Hady Gepreel, Mohamed; Niinomi, Mitsuo

    2013-04-01

    The design of new low-cost Ti-alloys with high biocompatibility for implant applications, using ubiquitous alloying elements in order to establish the strategic method for suppressing utilization of rare metals, is a challenge. To meet the demands of longer human life and implantation in younger patients, the development of novel metallic alloys for biomedical applications is aiming at providing structural materials with excellent chemical, mechanical and biological biocompatibility. It is, therefore, likely that the next generation of structural materials for replacing hard human tissue would be of those Ti-alloys that do not contain any of the cytotoxic elements, elements suspected of causing neurological disorders or elements that have allergic effect. Among the other mechanical properties, the low Young's modulus alloys have been given a special attention recently, in order to avoid the occurrence of stress shielding after implantation. Therefore, many Ti-alloys were developed consisting of biocompatible elements such as Ti, Zr, Nb, Mo, and Ta, and showed excellent mechanical properties including low Young's modulus. However, a recent attention was directed towards the development of low cost-alloys that have a minimum amount of the high melting point and high cost rare-earth elements such as Ta, Nb, Mo, and W. This comes with substituting these metals with the common low cost, low melting point and biocompatible metals such as Fe, Mn, Sn, and Si, while keeping excellent mechanical properties without deterioration. Therefore, the investigation of mechanical and biological biocompatibility of those low-cost Ti-alloys is highly recommended now lead towards commercial alloys with excellent biocompatibility for long-term implantation. PMID:23507261

  8. Controlling optical properties of biotissue by the use of biocompatible hyperosmotic agents

    NASA Astrophysics Data System (ADS)

    Jiang, Jingying; Wang, Ruikang K.; Xu, Kexin

    2007-02-01

    Previous results of tissue optical clearing have qualitatively indicated that optical properties of bio-tissue can be changed by the use of biocompatible hyperosmotic agents. In this talk, it is our aim to try to quantitatively evaluate how relative between changes of optical properties and hyperosmotic agents. Tissue-like turbid media, i.e. intralipid-10% suspension and porcine skin tissues, medicated without and with biocompatible hyperosmotic agents, have been investigated within NIR range. Optical parameters (absorption coefficient, scattering coefficient and anisotropy factor) of samples have been calculated by Inverse Adding-Doubling (IAD) modelling method. The results have demonstrated that optical property parameters (absorption coefficient, scattering coefficient and anisotropy factor) of tissue samples have changed with the course of the administration of biocompatible hyperosmotic agents into intralipid-10% suspension and porcine skin tissues respectively. This reveals better refractive index matching environment has been gradually created within tissue. Further, the results have showed the potential capabilities to quantitatively control optical properties of bio-tissue in this way. Therefore, this would facilitate explanation of the mechanism of tissue optical clearing by the use of biocompatible hyperosmotic agents.

  9. Bioinspired, Ultrastrong, Highly Biocompatible, and Bioactive Natural Polymer/Graphene Oxide Nanocomposite Films.

    PubMed

    Zhu, Wen-Kun; Cong, Huai-Ping; Yao, Hong-Bin; Mao, Li-Bo; Asiri, Abdullah M; Alamry, Khalid A; Marwani, Hadi M; Yu, Shu-Hong

    2015-09-01

    Tough and biocompatible nanocomposite films: A new type of bioinspired ultrastrong, highly biocompatible, and bioactive konjac glucomannan (KGM)/graphene oxide (GO) nanocomposite film is fabricated on a large scale by a simple solution-casting method. Such KGM-GO composite films exhibit much enhanced mechanical properties under the strong hydrogen-bonding interactions, showing great potential in the fields of tissue engineering and food package. PMID:26097134

  10. Antimicrobial biocompatible bioscaffolds for orthopaedic implants.

    PubMed

    Qureshi, Ammar T; Terrell, Lekeith; Monroe, W Todd; Dasa, Vinod; Janes, Marlene E; Gimble, Jeffrey M; Hayes, Daniel J

    2014-05-01

    Nationally, nearly 1.5 million patients in the USA suffer from ailments requiring bone grafts and hip and other joint replacements. Infections following internal fixation in orthopaedic trauma can cause osteomyelitis in 22-66% of cases and, if uncontrolled, the mortality rate can be as high as 2%. We characterize a procedure for the synthesis of antimicrobial and biocompatible poly-l-lactic acid (PLLA) and poly-ethyleneglycol (PEG) bioscaffolds designed to degrade and absorb at a controlled rate. The bioscaffold architecture aims to provide a suitable substrate for the controlled release of silver nanoparticles (SNPs) to reduce bacterial growth and to aid the proliferation of human adipose-derived stem cells (hASCs) for tissue-engineering applications. The fabricated bioscaffolds were characterized by scanning transmission microscope (SEM) and it showed that the addition of tncreasing concentrations of SNPs results in the formation of dendritic porous channels perpendicular to the axis of precipitation. The antimicrobial properties of these porous bioscaffolds were tested according to a modified ISO 22196 standard across varying concentrations of biomass-mediated SNPs to determine an efficacious antimicrobial concentration. The bioscaffolds reduced the Staphylococcus aureus and Escherichia coli viable colony-forming units by 98.85% and 99.9%, respectively, at an antimicrobial SNPs concentration of 2000 ppm. Human ASCs were seeded on bioscaffolds and cultured in vitro for 20 days to study the effect of SNPs concentration on the viability of cells. SEM analysis and the metabolic activity-based fluorescent dye, AlamarBlue®, demonstrated the growth of cells on the efficacious antimicrobial bioscaffolds. The biocompatibility of in vitro leached silver, quantified by inductively coupled plasma optical emission spectroscopy (ICP-OES), proved non-cytotoxic when tested against hASCs, as evaluated by MTT assay. PMID:22700366

  11. Cysteine modified polyaniline films improve biocompatibility for two cell lines.

    PubMed

    Yslas, Edith I; Cavallo, Pablo; Acevedo, Diego F; Barbero, César A; Rivarola, Viviana A

    2015-06-01

    This work focuses on one of the most exciting application areas of conjugated conducting polymers, which is cell culture and tissue engineering. To improve the biocompatibility of conducting polymers we present an easy method that involves the modification of the polymer backbone using l-cysteine. In this publication, we show the synthesis of polyaniline (PANI) films supported onto Polyethylene terephthalate (PET) films, and modified using cysteine (PANI-Cys) in order to generate a biocompatible substrate for cell culture. The PANI-Cys films are characterized by Fourier Transform infrared and UV-visible spectroscopy. The changes in the hydrophilicity of the polymer films after and before the modification were tested using contact angle measurements. After modification the contact angle changes from 86°±1 to 90°±1, suggesting a more hydrophylic surface. The adhesion properties of LM2 and HaCaT cell lines on the surface of PANI-Cys films in comparison with tissue culture plastic (TCP) are studied. The PANI-Cys film shows better biocompatibility than PANI film for both cell lines. The cell morphologies on the TCP and PANI-Cys film were examined by florescence and Atomic Force Microscopy (AFM). Microscopic observations show normal cellular behavior when PANI-Cys is used as a substrate of both cell lines (HaCaT and LM2) as when they are cultured on TCP. The ability of these PANI-Cys films to support cell attachment and growth indicates their potential use as biocompatible surfaces and in tissue engineering. PMID:25842107

  12. The effect of temperature and humidity on adhesion of a gecko-inspired adhesive: implications for the natural system

    PubMed Central

    Stark, Alyssa Y.; Klittich, Mena R.; Sitti, Metin; Niewiarowski, Peter H.; Dhinojwala, Ali

    2016-01-01

    The adhesive system of geckos has inspired hundreds of synthetic adhesives. While this system has been used relentlessly as a source of inspiration, less work has been done in reverse, where synthetics are used to test questions and hypotheses about the natural system. Here we take such an approach. We tested shear adhesion of a mushroom-tipped synthetic gecko adhesive under conditions that produced perplexing results in the natural adhesive system. Synthetic samples were tested at two temperatures (12 °C and 32 °C) and four different humidity levels (30%, 55%, 70%, and 80% RH). Surprisingly, adhesive performance of the synthetic samples matched that of living geckos, suggesting that uncontrolled parameters in the natural system, such as surface chemistry and material changes, may not be as influential in whole-animal performance as previously thought. There was one difference, however, when comparing natural and synthetic adhesive performance. At 12 °C and 80% RH, adhesion of the synthetic structures was lower than expected based on the natural system’s performance. Our approach highlights a unique opportunity for both biologists and material scientists, where new questions and hypotheses can be fueled by joint comparisons of the natural and synthetic systems, ultimately improving knowledge of both. PMID:27480603

  13. The effect of temperature and humidity on adhesion of a gecko-inspired adhesive: implications for the natural system.

    PubMed

    Stark, Alyssa Y; Klittich, Mena R; Sitti, Metin; Niewiarowski, Peter H; Dhinojwala, Ali

    2016-01-01

    The adhesive system of geckos has inspired hundreds of synthetic adhesives. While this system has been used relentlessly as a source of inspiration, less work has been done in reverse, where synthetics are used to test questions and hypotheses about the natural system. Here we take such an approach. We tested shear adhesion of a mushroom-tipped synthetic gecko adhesive under conditions that produced perplexing results in the natural adhesive system. Synthetic samples were tested at two temperatures (12 °C and 32 °C) and four different humidity levels (30%, 55%, 70%, and 80% RH). Surprisingly, adhesive performance of the synthetic samples matched that of living geckos, suggesting that uncontrolled parameters in the natural system, such as surface chemistry and material changes, may not be as influential in whole-animal performance as previously thought. There was one difference, however, when comparing natural and synthetic adhesive performance. At 12 °C and 80% RH, adhesion of the synthetic structures was lower than expected based on the natural system's performance. Our approach highlights a unique opportunity for both biologists and material scientists, where new questions and hypotheses can be fueled by joint comparisons of the natural and synthetic systems, ultimately improving knowledge of both. PMID:27480603

  14. In vitro and in vivo ocular biocompatibility of electrospun poly(ɛ-caprolactone) nanofibers.

    PubMed

    Da Silva, Gisele Rodrigues; Lima, Tadeu Henrique; Oréfice, Rodrigo Lambert; Fernandes-Cunha, Gabriella Maria; Silva-Cunha, Armando; Zhao, Min; Behar-Cohen, Francine

    2015-06-20

    Biocompatibility is a requirement for the development of nanofibers for ophthalmic applications. In this study, nanofibers were elaborated using poly(ε-caprolactone) via electrospinning. The ocular biocompatibility of this material was investigated. MIO-M1 and ARPE-19 cell cultures were incubated with nanofibers and cellular responses were monitored by viability and morphology. The in vitro biocompatibility revealed that the nanofibers were not cytotoxic to the ocular cells. These cells exposed to the nanofibers proliferated and formed an organized monolayer. ARPE-19 and MIO-M1 cells were capable of expressing GFAP, respectively, demonstrating their functionality. Nanofibers were inserted into the vitreous cavity of the rat's eye for 10days and the in vivo biocompatibility was investigated using Optical Coherence Tomography (OCT), histology and measuring the expression of pro-inflammatory genes (IL-1β, TNF-α, VEGF and iNOS) (real-time PCR). The OCT and the histological analyzes exhibited the preserved architecture of the tissues of the eye. The biomaterial did not elicit an inflammatory reaction and pro-inflammatory cytokines were not expressed by the retinal cells, and the other posterior tissues of the eye. Results from the biocompatibility studies indicated that the nanofibers exhibited a high degree of cellular biocompatibility and short-term intraocular tolerance, indicating that they might be applied as drug carrier for ophthalmic use. PMID:25797289

  15. Enhanced Biocompatibility of Porous Nitinol

    PubMed Central

    Munroe, Norman; Pulletikurthi, Chandan; Haider, Waseem

    2009-01-01

    Porous Nitinol (PNT) has found vast applications in the medical industry as interbody fusion devices, synthetic bone grafts, etc. However, the tendency of the PNT to corrode is anticipated to be greater as compared to solid nitinol since there is a larger surface area in contact with body fluids. In such cases, surface preparation is known to play a major role in a material’s biocompatibility. In an effort to check the effect of surface treatments on the in vitro corrosion properties of PNT, in this investigation, they were subjected to different surface treatments such as boiling in water, dry heating, and passivation. The localized corrosion resistance of alloys before and after each treatment was evaluated in phosphate buffer saline solution (PBS) using cyclic polarization tests in accordance with ASTM F 2129-08. PMID:19956797

  16. Polycrystalline Silicon: a Biocompatibility Assay

    SciTech Connect

    Pecheva, E.; Fingarova, D.; Pramatarova, L.; Hikov, T.; Laquerriere, P.; Bouthors, Sylvie; Dimova-Malinovska, D.; Montgomery, P.

    2010-01-21

    Polycrystalline silicon (poly-Si) layers were functionalized through the growth of biomimetic hydroxyapatite (HA) on their surface. HA is the mineral component of bones and teeth and thus possesses excellent bioactivity and biocompatibility. MG-63 osteoblast-like cells were cultured on both HA-coated and un-coated poly-Si surfaces for 1, 3, 5 and 7 days and toxicity, proliferation and cell morphology were investigated. The results revealed that the poly-Si layers were bioactive and compatible with the osteoblast-like cells. Nevertheless, the HA coating improved the cell interactions with the poly-Si surfaces based on the cell affinity to the specific chemical composition of the bone-like HA and/or to the higher HA roughness.

  17. Tribological study of lubricious DLC biocompatible coatings.

    PubMed

    Brizuela, M; Garcia-Luis, A; Viviente, J L; Braceras, I; Oñate, J I

    2002-12-01

    DLC (diamond-like carbon) coatings have remarkable tribological properties due mainly to their good frictional behavior. These coatings can be applied in many industrial and biomedical applications, where sliding can generate wear and frictional forces on the components, such as orthopaedic metal implants. This work reports on the development and tribological characterization of functionally gradient titanium alloyed DLC coatings. A PVD-magnetron sputtering technique has been used as the deposition method. The aim of this work was to study the tribological performance of the DLC coating when metal to metal contact (cobalt chromium or titanium alloys) takes place under dry and lubricated test conditions. Prior work by the authors demonstrates that the DLC coating reduced considerably the wear of the ultra-high-molecular-weight polyethylene (UHMWPE). The DLC coating during mechanical testing exhibited a high elastic recovery (65%) compared to the values obtained from Co-Cr-Mo (15%) and Ti-6Al-4V (23%). The coating exhibited an excellent tribo-performance against the Ti-6Al-4V and Co-Cr-Mo alloys, especially under dry conditions presenting a friction value of 0.12 and almost negligible wear. This coating has passed biocompatibility tests for implant devices on tissue/bone contact according to international standards (ISO 10993). PMID:15348654

  18. Biocompatibility of polysebacic anhydride microparticles with chondrocytes in engineered cartilage.

    PubMed

    Ponnurangam, Sathish; O'Connell, Grace D; Hung, Clark T; Somasundaran, Ponisseril

    2015-12-01

    One of main challenges in developing clinically relevant engineered cartilage is overcoming limited nutrient diffusion due to progressive elaboration of extracellular matrix at the periphery of the construct. Macro-channels have been used to decrease the nutrient path-length; however, the channels become occluded with matrix within weeks in culture, reducing nutrient diffusion. Alternatively, microparticles can be imbedded throughout the scaffold to provide localized nutrient delivery. In this study, we evaluated biocompatibility of polysebacic anhydride (PSA) polymers and the effectiveness of PSA-based microparticles for short-term delivery of nutrients in engineered cartilage. PSA-based microparticles were biocompatible with juvenile bovine chondrocytes for concentrations up to 2mg/mL; however, cytotoxicity was observed at 20mg/mL. Cytotoxicity at high concentrations is likely due to intracellular accumulation of PSA degradation products and resulting lipotoxicity. Cytotoxicity of PSA was partially reversed in the presence of bovine serum albumin. In conclusion, the findings from this study demonstrate concentration-dependent biocompatibility of PSA-based microparticles and potential application as a nutrient delivery vehicle that can be imbedded in scaffolds for tissue engineering. PMID:26398146

  19. Polymeric barrier membranes for device packaging, diffusive control and biocompatibility

    NASA Astrophysics Data System (ADS)

    Wasikiewicz, J. M.; Roohpour, N.; Paul, D.; Grahn, M.; Ateh, D.; Rehman, I.; Vadgama, P.

    2008-11-01

    Current state-of-the-art implantable micron feature electronic devices are capable of monitoring and stimulating functions in vivo. Within an EU Framework VI project a further step was taken in developing key microsystem technologies and communication methods that could bring intelligence directly to the human interface, in the form of reactive medical implants and ambulatory measurement systems. Information from these devices is planned to be transmitted out into the wider environment for remote processing. However, the packaging of such state-of-the-art devices to enhance tissue biocompatibility, and to protect conducting elements from in vivo corrosion during extended use, along with protecting the body from toxins leaching from implant components, remains a concern. Candidate polymeric barriers as hydration resistant and solute impermeable interfaces to mitigate such major problems of chronic implantation were investigated. Materials studied included silicone rubber, PVC, polyurethane, and diamond-like carbon (DLC). Polymer permeability to water solutes was marginally improved through incorporation of lipid into these structures. Surface biocompatibility was assessed on the basis of protein film deposition in vitro and by cell viability studies in tissue culture. Short-term toxicity was not observed for any of the tested materials, though there were substantial differences in hydration. Additionally, polypyrrole over active electrodes shows feasibility for controlled tissue interfacing whilst retaining electrical conductivity.

  20. Biocompatible implants and methods of making and attaching the same

    DOEpatents

    Rowley, Adrian P; Laude, Lucien D; Humayun, Mark S; Weiland, James D; Lotfi, Atoosa; Markland, Jr., Francis S

    2014-10-07

    The invention provides a biocompatible silicone implant that can be securely affixed to living tissue through interaction with integral membrane proteins (integrins). A silicone article containing a laser-activated surface is utilized to make the implant. One example is an implantable prosthesis to treat blindness caused by outer retinal degenerative diseases. The device bypasses damaged photoreceptors and electrically stimulates the undamaged neurons of the retina. Electrical stimulation is achieved using a silicone microelectrode array (MEA). A safe, protein adhesive is used in attaching the MEA to the retinal surface and assist in alleviating focal pressure effects. Methods of making and attaching such implants are also provided.

  1. Biocompatibility of chemical-vapour-deposited diamond.

    PubMed

    Tang, L; Tsai, C; Gerberich, W W; Kruckeberg, L; Kania, D R

    1995-04-01

    The biocompatibility of chemical-vapour-deposited (CVD) diamond surfaces has been assessed. Our results indicate that CVD diamond is as biocompatible as titanium (Ti) and 316 stainless steel (SS). First, the amount of adsorbed and 'denatured' fibrinogen on CVD diamond was very close to that of Ti and SS. Second, both in vitro and in vivo there appears to be less cellular adhesion and activation on the surface of CVD diamond surfaces compared to Ti and SS. This evident biocompatibility, coupled with the corrosion resistance and notable mechanical integrity of CVD diamond, suggests that diamond-coated surfaces may be highly desirable in a number of biomedical applications. PMID:7654876

  2. In Vitro Models in Biocompatibility Assessment for Biomedical-Grade Chitosan Derivatives in Wound Management

    PubMed Central

    Keong, Lim Chin; Halim, Ahmad Sukari

    2009-01-01

    One of the ultimate goals of wound healing research is to find effective healing techniques that utilize the regeneration of similar tissues. This involves the modification of various wound dressing biomaterials for proper wound management. The biopolymer chitosan (β-1,4-D-glucosamine) has natural biocompatibility and biodegradability that render it suitable for wound management. By definition, a biocompatible biomaterial does not have toxic or injurious effects on biological systems. Chemical and physical modifications of chitosan influence its biocompatibility and biodegradability to an uncertain degree. Hence, the modified biomedical-grade of chitosan derivatives should be pre-examined in vitro in order to produce high-quality, biocompatible dressings. In vitro toxicity examinations are more favorable than those performed in vivo, as the results are more reproducible and predictive. In this paper, basic in vitro tools were used to evaluate cellular and molecular responses with regard to the biocompatibility of biomedical-grade chitosan. Three paramount experimental parameters of biocompatibility in vitro namely cytocompatibility, genotoxicity and skin pro-inflammatory cytokine expression, were generally reviewed for biomedical-grade chitosan as wound dressing. PMID:19399250

  3. Biocompatibility of crystalline opal nanoparticles

    PubMed Central

    2012-01-01

    Background Silica nanoparticles are being developed as a host of biomedical and biotechnological applications. For this reason, there are more studies about biocompatibility of silica with amorphous and crystalline structure. Except hydrated silica (opal), despite is presents directly and indirectly in humans. Two sizes of crystalline opal nanoparticles were investigated in this work under criteria of toxicology. Methods In particular, cytotoxic and genotoxic effects caused by opal nanoparticles (80 and 120 nm) were evaluated in cultured mouse cells via a set of bioassays, methylthiazolyldiphenyl-tetrazolium-bromide (MTT) and 5-bromo-2′-deoxyuridine (BrdU). Results 3T3-NIH cells were incubated for 24 and 72 h in contact with nanocrystalline opal particles, not presented significant statistically difference in the results of cytotoxicity. Genotoxicity tests of crystalline opal nanoparticles were performed by the BrdU assay on the same cultured cells for 24 h incubation. The reduction of BrdU-incorporated cells indicates that nanocrystalline opal exposure did not caused unrepairable damage DNA. Conclusions There is no relationship between that particles size and MTT reduction, as well as BrdU incorporation, such that the opal particles did not induce cytotoxic effect and genotoxicity in cultured mouse cells. PMID:23088559

  4. Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 1. Intracanal drugs and substances.

    PubMed

    Hauman, C H J; Love, R M

    2003-02-01

    Irrigation solutions and intracanal medicaments are used within the root canal to clean and aid in disinfecting the dentinal walls. Although these materials are intended to be contained within the root canal, they invariably contact the periapical tissues, either through inadvertent extrusion through the apex or leaching. This paper is a review on the methodology involved in biocompatibility testing followed by a discussion on biocompatibility of contemporary intracanal drugs and substances used in endodontics. PMID:12657150

  5. In vivo biocompatibility of radiation crosslinked acrylamide copolymers

    NASA Astrophysics Data System (ADS)

    Saraydın, Dursun; Ünver-Saraydın, Serpil; Karadağ, Erdener; Koptagel, Emel; Güven, Olgun

    2004-04-01

    In vitro swelling and in vivo biocompatibility of radiation crosslinked acrylamide copolymers such as acrylamide/crotonic acid (AAm/CA) and acrylamide/itaconic acid (AAm/IA) were studied. The swelling kinetics of acrylamide copolymers were performed in distilled water, human serum and some simulated physiological fluids such as phosphate buffer, pH 7.4, glycine-HCl buffer, pH 1.1, physiological saline solution, and some swelling and diffusion parameters have been calculated. AAm/CA and AAm/IA hydrogels were subcutaneously implanted in rats for up to 10 weeks and the immediate short- and long-term tissue response to these implants were investigated. Histological analysis indicated that tissue reaction at the implant site progressed from an initial acute inflammatory response. No necrosis, tumorigenesis or infection was observed at the implant site up to 10 weeks. The radiation crosslinked AAm/CA and AAm/IA copolymers were found well tolerated, non-toxic and highly biocompatible. However, AAm/IA copolymer was not found to be compatible biomaterials, because one of the AAm/IA samples was disintegrated into small pieces in the rat.

  6. Biocompatible xanthan/polypyrrole scaffolds for tissue engineering.

    PubMed

    Bueno, Vania Blasques; Takahashi, Suelen Harumi; Catalani, Luiz Henrique; de Torresi, Susana Ines Cordoba; Petri, Denise Freitas Siqueira

    2015-01-01

    Polypyrrole (PPy) was electropolymerized in xanthan hydrogels (XCA), resulting in electroactive XCAPPy scaffolds with (15 ± 3) wt.% PPy and (40 ± 10) μm thick. The physicochemical characterization of hybrid XCAPPy scaffolds was performed by means of cyclic voltammetry, swelling tests, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analyses (TGA), scanning electron microscopy (SEM), atomic force microscopy (AFM) and tensile tests. XCAPPy swelled~80% less than XCA. FTIR spectra and thermal analyses did not evidence strong interaction between PPy and XCA matrix. XCAPPy presented a porous stratified structure resulting from the arrangement of PPy chains parallel to XCA surface. Under stress XCAPPy presented larger strain than neat XCA probably due to the sliding of planar PPy chains. The adhesion and proliferation of fibroblasts onto XCA and XCAPPy were evaluated in the absence and in the presence of external magnetic field (EMF) of 0.4T, after one day, 7 days, 14 days and 21 days. Fibroblast proliferation was more pronounced onto XCAPPy than onto XCA, due to its higher hydrophobicity and surface roughness. EMF stimulated cell proliferation onto both scaffolds. PMID:25953548

  7. Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 2. Root-canal-filling materials.

    PubMed

    Hauman, C H J; Love, R M

    2003-03-01

    Root-canal-filling materials are either placed directly onto vital periapical tissues or may leach through dentine. The tissue response to these materials therefore becomes important and may influence the outcome of endodontic treatment. This paper is a review of the biocompatibility of contemporary orthograde and retrograde root-canal-filling materials. PMID:12657140

  8. Mechanical Strength and Biocompatibility of Ultrafine-Grained Commercial Purity Titanium

    PubMed Central

    Estrin, Yuri; Kim, Hyoun-Ee; Lapovok, Rimma; Ng, Hoi Pang; Jo, Ji-Hoon

    2013-01-01

    The effect of grain refinement of commercial purity titanium by equal channel angular pressing (ECAP) on its mechanical performance and bone tissue regeneration is reported. In vivo studies conducted on New Zealand white rabbits did not show an enhancement of biocompatibility of ECAP-modified titanium found earlier by in vitro testing. However, the observed combination of outstanding mechanical properties achieved by ECAP without a loss of biocompatibility suggests that this is a very promising processing route to bioimplant manufacturing. The study thus supports the expectation that commercial purity titanium modified by ECAP can be seen as an excellent candidate material for bone implants suitable for replacing conventional titanium alloy implants. PMID:23936857

  9. Biocompatibility of Subcutaneously Implanted Plant-Derived Cellulose Biomaterials

    PubMed Central

    Pelling, Andrew E.

    2016-01-01

    There is intense interest in developing novel biomaterials which support the invasion and proliferation of living cells for potential applications in tissue engineering and regenerative medicine. Decellularization of existing tissues have formed the basis of one major approach to producing 3D scaffolds for such purposes. In this study, we utilize the native hypanthium tissue of apples and a simple preparation methodology to create implantable cellulose scaffolds. To examine biocompatibility, scaffolds were subcutaneously implanted in wild-type, immunocompetent mice (males and females; 6–9 weeks old). Following the implantation, the scaffolds were resected at 1, 4 and 8 weeks and processed for histological analysis (H&E, Masson’s Trichrome, anti-CD31 and anti-CD45 antibodies). Histological analysis revealed a characteristic foreign body response to the scaffold 1 week post-implantation. However, the immune response was observed to gradually disappear by 8 weeks post-implantation. By 8 weeks, there was no immune response in the surrounding dermis tissue and active fibroblast migration within the cellulose scaffold was observed. This was concomitant with the deposition of a new collagen extracellular matrix. Furthermore, active blood vessel formation within the scaffold was observed throughout the period of study indicating the pro-angiogenic properties of the native scaffolds. Finally, while the scaffolds retain much of their original shape they do undergo a slow deformation over the 8-week length of the study. Taken together, our results demonstrate that native cellulose scaffolds are biocompatible and exhibit promising potential as a surgical biomaterial. PMID:27328066

  10. Biocompatibility of Subcutaneously Implanted Plant-Derived Cellulose Biomaterials.

    PubMed

    Modulevsky, Daniel J; Cuerrier, Charles M; Pelling, Andrew E

    2016-01-01

    There is intense interest in developing novel biomaterials which support the invasion and proliferation of living cells for potential applications in tissue engineering and regenerative medicine. Decellularization of existing tissues have formed the basis of one major approach to producing 3D scaffolds for such purposes. In this study, we utilize the native hypanthium tissue of apples and a simple preparation methodology to create implantable cellulose scaffolds. To examine biocompatibility, scaffolds were subcutaneously implanted in wild-type, immunocompetent mice (males and females; 6-9 weeks old). Following the implantation, the scaffolds were resected at 1, 4 and 8 weeks and processed for histological analysis (H&E, Masson's Trichrome, anti-CD31 and anti-CD45 antibodies). Histological analysis revealed a characteristic foreign body response to the scaffold 1 week post-implantation. However, the immune response was observed to gradually disappear by 8 weeks post-implantation. By 8 weeks, there was no immune response in the surrounding dermis tissue and active fibroblast migration within the cellulose scaffold was observed. This was concomitant with the deposition of a new collagen extracellular matrix. Furthermore, active blood vessel formation within the scaffold was observed throughout the period of study indicating the pro-angiogenic properties of the native scaffolds. Finally, while the scaffolds retain much of their original shape they do undergo a slow deformation over the 8-week length of the study. Taken together, our results demonstrate that native cellulose scaffolds are biocompatible and exhibit promising potential as a surgical biomaterial. PMID:27328066

  11. Biocompatibility of reduced graphene oxide nanoscaffolds following acute spinal cord injury in rats

    PubMed Central

    Palejwala, Ali H.; Fridley, Jared S.; Mata, Javier A.; Samuel, Errol L. G.; Luerssen, Thomas G.; Perlaky, Laszlo; Kent, Thomas A.; Tour, James M.; Jea, Andrew

    2016-01-01

    Background: Graphene has unique electrical, physical, and chemical properties that may have great potential as a bioscaffold for neuronal regeneration after spinal cord injury. These nanoscaffolds have previously been shown to be biocompatible in vitro; in the present study, we wished to evaluate its biocompatibility in an in vivo spinal cord injury model. Methods: Graphene nanoscaffolds were prepared by the mild chemical reduction of graphene oxide. Twenty Wistar rats (19 male and 1 female) underwent hemispinal cord transection at approximately the T2 level. To bridge the lesion, graphene nanoscaffolds with a hydrogel were implanted immediately after spinal cord transection. Control animals were treated with hydrogel matrix alone. Histologic evaluation was performed 3 months after the spinal cord transection to assess in vivo biocompatibility of graphene and to measure the ingrowth of tissue elements adjacent to the graphene nanoscaffold. Results: The graphene nanoscaffolds adhered well to the spinal cord tissue. There was no area of pseudocyst around the scaffolds suggestive of cytotoxicity. Instead, histological evaluation showed an ingrowth of connective tissue elements, blood vessels, neurofilaments, and Schwann cells around the graphene nanoscaffolds. Conclusions: Graphene is a nanomaterial that is biocompatible with neurons and may have significant biomedical application. It may provide a scaffold for the ingrowth of regenerating axons after spinal cord injury. PMID:27625885

  12. Recent advances in synthesis, characterization of hydroxyapatite/polyurethane composites and study of their biocompatible properties.

    PubMed

    Popescu, L M; Piticescu, R M; Antonelli, A; Rusti, C F; Carboni, E; Sfara, C; Magnani, M; Badilita, V; Vasile, E; Trusca, R; Buruiana, T

    2013-11-01

    The development of engineered biomaterials that mimic bone tissues is a promising research area that benefits from a growing interest. Polymers and polymer-ceramic composites are the principle materials investigated for the development of synthetic bone scaffolds thanks to their proven biocompatibility and biostability. Several polymers have been combined with calcium phosphates (mainly hydroxyapatite) to prepare nanocomposites with improved biocompatible and mechanical properties. Here, we report the hydrothermal synthesis in high pressure conditions of nanostructured composites based on hydroxyapatite and polyurethane functionalized with carboxyl and thiol groups. Cell-material interactions were investigated for potential applications of these new types of composites as coating for orthopedic implants. Physical-chemical and morphological characteristics of hydroxyapatite/polyurethane composites were evaluated for different compositions, showing their dependence on synthesis parameters (pressure, temperature). In vitro experiments, performed to verify if these composites are biocompatible cell culture substrates, showed that they are not toxic and do not affect cell viability. PMID:23877879

  13. Biocompatibility of glass ionomer cements with and without chlorhexidine

    PubMed Central

    Iz, Sultan Gulce; Ertugrul, Fahinur; Eden, Ece; Gurhan, S. Ismet Deliloglu

    2013-01-01

    Objective: The aim of the present study is to evaluate the biocompatibility of glass ionomer cements (GICs) with and without chlorhexidine (CHX) as well as coated with varnish or not using in vitro cytotoxicity test. Materials and Methods: Biocompatibility of Fuji IX, Fuji IX with varnish, Fuji IX with 1% CHX diacetate and Fuji IX with 1% CHX diacetate with varnish was determined with in vitro cytotoxicity assay by using L929 mouse connective tissue fibroblasts. After 72 h, cell viabilities were evaluated by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay to determine the effects of the cements on the mitochondrial function and microscopic images were taken by scanning electron microscopy. Results: Statistical analysis was performed by one-way analysis of variance followed by the Bonferroni post-hoc test at a significance level of P < 0.05. 72 h after treatment, there were statistically significant differences between Fuji IX and Fuji IX-CHX (P < 0.001). In addition, the reduction of the cytotoxicity by coating the GICs with varnish was indicative and increased the cell viability ratio (P < 0.001). Conclusions: Fuji IX coated with varnish was found to be the most biocompatible one among others. Thus adding CHX significantly reduced the cell viability, it is assumed that, due to the leakage of CHX and the other components of the GICs to the cell culture medium, the cell viabilities were decreased, so it is highly recommended to use varnish not only to reduce the water loss from the GICs, but also to reduce the cytotoxicity of the GICs. PMID:24966735

  14. A pore way to heal and regenerate: 21st century thinking on biocompatibility

    PubMed Central

    Ratner, Buddy D.

    2016-01-01

    This article raises central questions about the definition of biocompatibility, and also about how we assess biocompatibility. We start with the observation that a porous polymer where every pore is spherical, ∼40 microns in diameter and interconnected, can heal into vascularized tissues with little or no fibrosis and good restoration of vascularity (i.e., little or no foreign body reaction). The same polymer in solid form will trigger the classic foreign body reaction characterized by a dense, collagenous foreign body capsule and low vascularity. A widely used definition of biocompatibility is ‘the ability of a material to perform with an appropriate host response in a specific application’. With precision-porous polymers, in direct comparison with the same polymer in solid form, we have the same material, in the same application, with two entirely different biological reactions. Can both reactions be ‘biocompatible?’ This conundrum will be elaborated upon and proposals will be made for future considerations and measurement of biocompatibility. PMID:27047676

  15. A pore way to heal and regenerate: 21st century thinking on biocompatibility.

    PubMed

    Ratner, Buddy D

    2016-06-01

    This article raises central questions about the definition of biocompatibility, and also about how we assess biocompatibility. We start with the observation that a porous polymer where every pore is spherical, ∼40 microns in diameter and interconnected, can heal into vascularized tissues with little or no fibrosis and good restoration of vascularity (i.e., little or no foreign body reaction). The same polymer in solid form will trigger the classic foreign body reaction characterized by a dense, collagenous foreign body capsule and low vascularity. A widely used definition of biocompatibility is 'the ability of a material to perform with an appropriate host response in a specific application'. With precision-porous polymers, in direct comparison with the same polymer in solid form, we have the same material, in the same application, with two entirely different biological reactions. Can both reactions be 'biocompatible?' This conundrum will be elaborated upon and proposals will be made for future considerations and measurement of biocompatibility. PMID:27047676

  16. Biocompatible composites of ultrahigh molecular weight polyethylene

    NASA Astrophysics Data System (ADS)

    Panin, S. V.; Kornienko, L. A.; Suan, T. Nguen; Ivanova, L. P.; Korchagin, M. A.; Chaikina, M. V.; Shilko, S. V.; Pleskachevskiy, Yu. M.

    2015-10-01

    Mechanical and tribotechnical characteristics of biocompatible, antifriction and extrudable composites based on ultrahigh molecular weight polyethylene (UHMWPE) as well as hybrid matrix "UHMWPE + PTFE" with biocompatible hydroxyapatite filler under the dry friction and boundary lubrication were investigated. A comparative analysis of effectiveness of adding the hydroxyapatite to improve the wear resistance of composites based on these two matrices was performed. It is shown that the wear intensity of nanocomposites based on the hybrid matrix is lower than that for the composites based on pure UHMWPE. Possibilities of using the composites of the polymer "UHMWPE-PTFE" mixture as a material for artificial joints implants are discussed.

  17. Biocompatibility of supercritical CO2-treated titanium implants in a rat model.

    PubMed

    Hill, C M; Kang, Q K; Wahl, C; Jimenez, A; Laberge, M; Drews, M; Matthews, M A; An, Y H

    2006-04-01

    Supercritical phase CO2 is a promising method for sterilizing implantable devices and tissue grafts. The goal of this study is to evaluate the biocompatibility of titanium implants sterilized by supercritical phase CO2 in a rat subcutaneous implantation model. At 5 weeks post implantation titanium implants sterilized by supercritical phase CO2 produce a soft tissue reaction that is comparable to other methods of sterilization (steam autoclave, ultraviolet light radiation, ethylene oxide gas, and radio-frequency glow-discharge), as indicated by the thickness and density of the foreign body capsule, although there were some differences on the capillary density. Overall the soft tissue response to the implants was similar among all methods of sterilization, indicating supercritical phase CO2 treatment did not compromise the biocompatibility of the titanium implant. PMID:16705612

  18. Biocompatibility of metal injection molded versus wrought ASTM F562 (MP35N) and ASTM F1537 (CCM) cobalt alloys.

    PubMed

    Chen, Hao; Sago, Alan; West, Shari; Farina, Jeff; Eckert, John; Broadley, Mark

    2011-01-01

    We present a comparative analysis between biocompatibility test results of wrought and Metal Injection Molded (MIM) ASTM F562-02 UNS R30035 (MP35N) and F1537 UNS R31538 (CCM) alloy samples that have undergone the same generic orthopedic implant's mechanical, chemical surface pre-treatment, and a designed pre-testing sample preparation method. Because the biocompatibility properties resulting from this new MIM cobalt alloy process are not well understood, we conducted tests to evaluate cytotoxicity (in vitro), hemolysis (in vitro), toxicity effects (in vivo), tissue irritation level (in vivo), and pyrogenicity count (in vitro) on such samples. We show that our developed MIM MP35N and CCM materials and treatment processes are biocompatible, and that both the MIM and wrought samples, although somewhat different in microstructure and surface, do not show significant differences in biocompatibility. PMID:21537059

  19. Sutureless closure of scleral wounds in animal models by the use of laser welded biocompatible patches

    NASA Astrophysics Data System (ADS)

    Rossi, Francesca; Matteini, Paolo; Menabuoni, Luca; Lenzetti, Ivo; Pini, Roberto

    2011-03-01

    The common procedures used to seal the scleral or conjunctival injuries are based on the traditional suturing techniques, that may induce foreign body reaction during the follow up, with subsequent inflammation and distress for the patient. In this work we present an experimental study on the laser welding of biocompatible patches onto ocular tissues, for the closure of surgical or trauma wounds. The study was performed ex vivo in animal models (porcine eyes). A penetrating perforation of the ocular tissue was performed with a surgical knife. The wound walls were approximated, and a biocompatible patch was put onto the outer surface of the tissue, in order to completely cover the wound as a plaster. The patches were prepared with a biocompatible and biodegradable polymer, showing high mechanical strength, good elasticity, high permeability for vapour and gases and rather low biodegradation. During preparation, Indocyanine Green (ICG) was included in the biopolymeric matrix, so that the films presented high absorption at 810 nm. Effective adhesion of the membranes to the ocular tissues was obtained by using diode laser light emitted from an 810 nm diode laser and delivered by means of a 300 μm core diameter optical fiber, to produce spots of local film/tissue adhesion, due to the photothermal effect at the interface. The result is an immediate closure of the wound, thus reducing post-operative complications due to inflammation.

  20. Biocompatible Silk-Poly(Pyrrole) Composite Trilayer Electromechanical Actuators

    NASA Astrophysics Data System (ADS)

    Klemke, Carly; Bradshaw, Nathan; Larson, Jesse; Severt, Sean; Ostrovsky-Snider, Nicholas; Murphy, Amanda; Leger, Janelle

    2015-03-01

    Biocompatible materials capable of controlled actuation are in high demand for use in biomedical applications such as dynamic tissue scaffolding, valves, and steerable surgical tools. Conducting polymers (CPs) have some desirable traits for use as an actuator, such as the ability to operate in biologically relevant fluids and responsiveness to low voltages. However CPs alone are limited due to their brittle nature and poor solubility. Recently we have shown that a composite material of silk and the CP poly(pyrrole) (PPy) shows promising characteristics as an actuator; it is mechanically robust as well as fully biocompatible. Initial proof-of-concept experiments demonstrated that these composites bend under an applied voltage (or current) using a simple bilayer device. Here we present the development of a trilayer device, composed of two conductive layers separated by an insulating silk layer. This configuration has twice the active surface area as a bilayer, potentially increasing the amount of mechanical motion per volt applied. We will discuss the fabrication and characterization of these devices, as well as their performance and future applications of this technology.

  1. Biocompatible Silk-Poly(Pyrrole) Composite Trilayer Actuators

    NASA Astrophysics Data System (ADS)

    Fengel, Carly; Bradshaw, Nathan; Severt, Sean; Murphy, Amanda; Leger, Janelle

    Biocompatible materials capable of controlled actuation are in high demand for use in biomedical applications such as dynamic tissue scaffolding, valves, and steerable surgical tools. Conducting polymers (CPs) have some desirable traits for use as an actuator, such as the ability to operate in biologically relevant fluids and responsiveness to low voltages. However CPs alone are limited due to their brittle nature and poor solubility. Recently we have shown that a composite material of silk and the CP poly(pyrrole) (PPy) shows promising characteristics as an actuator; it is mechanically robust as well as fully biocompatible. Initial proof-of-concept experiments demonstrated that these composites bend under an applied voltage (or current) using a simple bilayer device. Here we present trilayer devices composed of two silk-PPy composite layers separated by an insulating silk layer. This configuration results in more charge is passed in comparison to the analogous bilayer system, as well as a more sustainable current response through cycling, resulting in a larger angle of deflection per volt applied. In addition, the motion of the trilayer devices is more symmetric than that of the bilayer analogs, resulting in a more repeatable movement. We will discuss the fabrication and characterization of these devices, as well as their performance and future applications of this technology.

  2. Biocompatibility of beta-stabilizing elements of titanium alloys.

    PubMed

    Eisenbarth, E; Velten, D; Müller, M; Thull, R; Breme, J

    2004-11-01

    In comparison to the presently used alpha + beta titanium alloys for biomedical applications, beta-titanium alloys have many advantageous mechanical properties, such as an improved wear resistance, a high elasticity and an excellent cold and hot formability. This will promote their future increased application as materials for orthopaedic joint replacements. Not all elements with beta-stabilizing properties in titanium alloys are suitable for biomaterial applications-corrosion and wear processes cause a release of these alloying elements to the surrounding tissue. In this investigation, the biocompability of alloying elements for beta- and near beta-titanium alloys was tested in order to estimate their suitability for biomaterial components. Titanium (grade 2) and the implant steel X2CrNiMo18153 (AISI 316 L) were tested as reference materials. The investigation included the corrosion properties of the elements, proliferation, mitochondrial activity, cell morphology and the size of MC3T3-E1 cells and GM7373 cells after 7 days incubation in direct contact with polished slices of the metals. The statistical significance was considered by Weir-test and Lord-test (alpha = 0.05). The biocompatibility range of the investigated metals is (decreasing biocompatibility): niobium-tantalum, titanium, zirconium-aluminium-316 L-molybdenum. PMID:15147816

  3. Biocompatibility of Experimental Polymeric Tracheal Matrices.

    PubMed

    Kiselevskii, M V; Chikileva, I O; Vlasenko, R Ya; Sitdikova, S M; Tenchurin, T Kh; Mamagulashvili, V G; Shepelev, A D; Grigoriev, T A; Chvalun, S N

    2016-08-01

    Biocompatibility of a new tracheal matrix is studied. The new matrix is based on polymeric ultra-fiber material colonized by mesenchymal multipotent stromal cells. The experiments demonstrate cytoconductivity of the synthetic matrices and no signs of their degradation within 2 months after their implantation to recipient mice. These data suggest further studies of the synthetic tracheal matrices on large laboratory animals. PMID:27591876

  4. Preparation of small bio-compatible microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor)

    1979-01-01

    Small, round, bio-compatible microspheres capable of covalently bonding proteins and having a uniform diameter below about 3500 A are prepared by substantially instantaneously initiating polymerization of an aqueous emulsion containing no more than 35% total monomer including an acrylic monomer substituted with a covalently bondable group such a hydroxyl, amino or carboxyl and a minor amount of a cross-linking agent.

  5. Thin film of biocompatible polysaccharides

    NASA Astrophysics Data System (ADS)

    Richert, Ludovic; Lavalle, Philippe; Schaaf, Pierre; Voegel, Jean-Claude; Picart, Catherine

    2003-03-01

    The layer-by-layer deposition method proposed by Decher et al. (1991) is a very simple and versatile method used to build thin films. These films are of interest for bioengineering because of their unique properties and of the possible insertion of bioactive molecules. We present here the peculiar properties of a new kind of film formed with natural biopolymers, namely hyaluronan (HA)and chitosan (CHI). The films may be used as biomimetic substrates to control bacterial and cell adhesion. These polysaccharides are of particular interest because they are biodegradable, non toxic, and can be found in various tissues. Hyaluronan is also a natural ligand for a numerous type of cells through the CD44 receptor. Chitosan has already largely been used for its biological and anti-microbial properties. (CHI/HA) films were built in acidic pH at different ionic strength. The buildup was followed in situ by optical waveguide lightmode spectroscopy (OWLS), quartz crystal microbalance, streaming potential measurements and atomic force microscopy. The kinetics of adsorption and desorption of the polyelectrolytes depended on the ionic strength. Small islands were initially present on the surface which grew by mutual coalescence until becoming a flat film. The films were around 200 nm in thickness. These results suggest that different types of thin films constituted of polysaccharides can be built on any type of surface. These films are currently investigated toward their cell adhesion and bacterial adhesion properties.

  6. Physicochemical characterization and biocompatibility of alginate-polycation microcapsules designed for islet transplantation

    NASA Astrophysics Data System (ADS)

    Tam, Susan Kimberly

    Microencapsulation represents a method for immunoprotecting transplanted therapeutic cells or tissues from graft rejection using a physical barrier. This approach is advantageous in that it eliminates the need to induce long-term immunosuppression and allows the option of transplanting non-cadaveric cell sources, such as animal cells and stem cell-derived tissues. The microcapsules that we have investigated are designed to immunoprotect islets of Langerhans (i.e. clusters of insulin-secreting cells), with the goal of treating insulin-dependent diabetes. With the aid of techniques for physicochemical analysis, this research focused on understanding which properties of the microcapsule are the most important for determining its biocompatibility. The objective of this work was to elucidate correlations between the chemical make-up, physicochemical properties, and in vivo biocompatibility of alginate-based microcapsules. Our approach was based on the hypothesis that the immune response to the microcapsules is governed by, and can therefore be controlled by, specific physicochemical properties of the microcapsule and its material components. The experimental work was divided into five phases, each associated with a specific aim : (1) To prove that immunoglobulins adsorb to the surface of alginate-polycation microcapsules, and to correlate this adsorption with the microcapsule chemistry. (2) To test interlaboratory reproducibility in making biocompatible microcapsules, and evaluate the suitability of our materials and fabrication protocols for subsequent studies. (3) To determine which physicochemical properties of alginates affect the in vivo biocompatibility of their gels. (4) To determine which physiochemical properties of alginate-polycation microcapsules are most important for determining their in vivo biocompatibility (5) To determine whether a modestly immunogenic membrane hinders or helps the ability of the microcapsule to immunoprotect islet xenografts in

  7. Vertically, interconnected carbon nanowalls as biocompatible scaffolds for osteoblast cells

    NASA Astrophysics Data System (ADS)

    Ion, Raluca; Vizireanu, Sorin; Luculescu, Catalin; Cimpean, Anisoara; Dinescu, Gheorghe

    2016-07-01

    The response of MC3T3-E1 pre-osteoblasts to vertically aligned, interconnected carbon nanowalls prepared by plasma enhanced chemical vapor deposition on silicon substrate has been evaluated in terms of cell adhesion, viability and cell proliferation. The behavior of osteoblasts seeded on carbon nanowalls was analyzed in parallel and compared with the behavior of the cells maintained in contact with tissue culture polystyrene (TCPS). The results demonstrate that osteoblasts adhere and remain viable in the long term on carbon nanowalls. Moreover, on the investigated scaffold cell proliferation was significantly promoted, although to a lower extent than on TCPS. Overall, the successful culture of osteoblasts on carbon nanowalls coated substrate confirms the biocompatibility of this scaffold, which could have potential applications in the development of orthopedic biomaterials.

  8. Biocompatible surgical meshes based on decellularized human amniotic membrane.

    PubMed

    Shi, Peina; Gao, Mengna; Shen, Qiuxia; Hou, Lei; Zhu, Yabin; Wang, Jun

    2015-09-01

    Meshes play important roles to repair human tissue defect. In this work, human amniotic membrane (HAM) was decellularized and explored the efficacy as an implantable biological mesh. Surfactant, hypertonic saline, lipase and DNAase were used individually or collectively to remove all cell components and remain the extracellular matrix. Results of H&E and DAPI staining demonstrated that the method of surfactant and lipase combining with DNAase is the most effective treatment for HAM decellularization. Primary smooth muscle cells were seeded to evaluate the decellularized HAM's (dHAM) in vitro cytocompatibility. The in vivo test was performed via implantation at rabbits' uterus with clinic polypropylene mesh (PP) as the control. The results indicated that dHAM possessed good biocompatibility and will be a potential candidate for biological mesh. PMID:26046274

  9. Biodegradation and biocompatibility of a degradable chitosan vascular prosthesis

    PubMed Central

    Kong, Xiaoying; Xu, Wenhua

    2015-01-01

    An instrument made by ourselves was used to fabricate biodegradable chitosan-heparin artificial vascular prosthesis with small internal diameter (2 mm) and different crosslinking degree from biodegradable chitosan, chitosan derivates and heparin. In vivo and in vitro degradation studies, inflammatory analysis and electron microscope scanning of this artificial vascular prosthesis were performed. It was observed that 50% of the prosthesis decomposed in vivo and was replaced by natural tissues. The degradation process of the chitosan-heparin artificial vascular prosthesis of small diameter could be controlled by changing the crosslinking degree. This kind of artificial vascular prosthesis shows good biocompatibility that can be controllability designed to achieve desirable in vascular replacement application. PMID:26064241

  10. An effective and biocompatible antibiofilm coating for central venous catheter.

    PubMed

    Silva Paes Leme, Annelisa Farah; Ferreira, Aline Siqueira; Alves, Fernanda Aparecida Oliveira; de Azevedo, Bruna Martinho; de Bretas, Liza Porcaro; Farias, Rogerio Estevam; Oliveira, Murilo Gomes; Raposo, Nádia Rezende Barbosa

    2015-05-01

    The aim of this study was to investigate the in vitro and in vivo efficacy and the tissue reaction of an antibiofilm coating composed of xylitol, triclosan, and polyhexamethylene biguanide. The antimicrobial activity was analyzed by a turbidimetric method. Scanning electron microscopy was used to evaluate the antiadherent property of central venous catheter (CVC) fragments impregnated with an antibiofilm coating (I-CVC) in comparison with noncoated CVC (NC-CVC) fragments. Two in vivo assays using subcutaneous implantation of NC-CVC and I-CVC fragments in the dorsal area of rats were performed. The first assay comprised hematological and microbiological analysis. The second assay evaluated tissue response by examining the inflammatory reactions after 7 and 21 days. The formulation displayed antimicrobial activity against all tested strains. A biofilm disaggregation with significant reduction of microorganism's adherence in I-CVC fragments was observed. In vivo antiadherence results demonstrated a reduction of early biofilm formation of Staphylococcus aureus ATCC 25923, mainly in an external surface of the I-CVC, in comparison with the NC-CVC. All animals displayed negative hemoculture. No significant tissue reaction was observed, indicating that the antibiofilm formulation could be considered biocompatible. The use of I-CVC could decrease the probability of development of localized or systemic infections. PMID:25826042

  11. Biocompatibility and degradation of tendon-derived scaffolds

    PubMed Central

    Alberti, Kyle A.; Xu, Qiaobing

    2016-01-01

    Decellularized extracellular matrix has often been used as a biomaterial for tissue engineering applications. Its function, once implanted can be crucial to determining whether a tissue engineered construct will be successful, both in terms of how the material breaks down, and how the body reacts to the material’s presence in the first place. Collagen is one of the primary components of extracellular matrix and has been used for a number of biomedical applications. Scaffolds comprised of highly aligned collagen fibrils can be fabricated directly from decellularized tendon using a slicing, stacking, and rolling technique, to create two- and three-dimensional constructs. Here, the degradation characteristics of the material are evaluated in vitro, showing that chemical crosslinking can reduce degradation while maintaining fiber structure. In vivo, non-crosslinked and crosslinked samples are implanted, and their biological response and degradation evaluated through histological sectioning, trichrome staining, and immunohistochemical staining for macrophages. Non-crosslinked samples are rapidly degraded and lose fiber morphology while crosslinked samples retain both macroscopic structure as well as fiber orientation. The cellular response of both materials is also investigated. The in vivo response demonstrates that the decellularized tendon material is biocompatible, biodegradable and can be crosslinked to maintain surface features for extended periods of time in vivo. This study provides material characteristics for the use of decellularized tendon as biomaterial for tissue engineering. PMID:26816651

  12. A biocompatible magnetic film: synthesis and characterization

    PubMed Central

    Chatterjee, Jhunu; Haik, Yousef; Chen, Ching Jen

    2004-01-01

    Background Biotechnology applications of magnetic gels include biosensors, targeted drug delivery, artificial muscles and magnetic buckles. These gels are produced by incorporating magnetic materials in the polymer composites. Methods A biocompatible magnetic gel film has been synthesized using polyvinyl alcohol. The magnetic gel was dried to generate a biocompatible magnetic film. Nanosized iron oxide particles (γ-Fe2O3, ~7 nm) have been used to produce the magnetic gel. Results The surface morphology and magnetic properties of the gel films were studied. The iron oxide particles are superparamagnetic and the gel film also showed superparamagnetic behavior. Conclusion Magnetic gel made out of crosslinked magnetic nanoparticles in the polymer network was found to be stable and possess the magnetic properties of the nanoparticles. PMID:14761251

  13. Electroactive biocompatible materials for nerve cell stimulation

    NASA Astrophysics Data System (ADS)

    Yang, Mei; Liang, Youlong; Gui, Qingyuan; Chen, Jun; Liu, Yong

    2015-04-01

    In the past decades, great efforts have been developed for neurobiologists and neurologists to restore nervous system functions. Recently much attention has been paid to electrical stimulation (ES) of the nervous system as a potential way to repair it. Various conductive biocompatible materials with good electrical conductivity, biocompatibility, and long-term ES or electrical stability have been developed as the substrates for ES. In this review, we summarized different types of materials developed in the purpose for ES of nervous system, including conducting polymers, carbon nanomaterials and composites from conducting polymer/carbon nanomaterials. The present review will give our perspective on the future research directions for further investigation on development of ES particularly on the nerve system.

  14. Biocompatibility of a new pulp capping cement

    PubMed Central

    Poggio, Claudio; Ceci, Matteo; Beltrami, Riccardo; Dagna, Alberto; Colombo, Marco; Chiesa, Marco

    2014-01-01

    Summary Aim The aim of the present study was to evaluate the biocompatibility of a new pulp capping material (Biodentine, Septodont) compared with reference pulp capping materials: Dycal (Dentsply), ProRoot MTA (Dentsply) and MTA-Angelus (Angelus) by using murine odontoblast cell line and Alamar blue and MTT cytotoxicity tests. Methods The citocompatibility of murine odontoblasts cells (MDPC-23) were evaluated at different times using a 24 Transwell culture plate by Alamar blue test and MTT assay. Results The results were significantly different among the pulp capping materials tested. Biocompatibility was significant different among materials with different composition. Conclusions Biodentine and MTA-based products show lower cytotoxicity varying from calcium hydroxide-based material which present higher citotoxicity. PMID:25002921

  15. Physicochemical characterization and biocompatibility of alginate-polycation microcapsules designed for islet transplantation

    NASA Astrophysics Data System (ADS)

    Tam, Susan Kimberly

    Microencapsulation represents a method for immunoprotecting transplanted therapeutic cells or tissues from graft rejection using a physical barrier. This approach is advantageous in that it eliminates the need to induce long-term immunosuppression and allows the option of transplanting non-cadaveric cell sources, such as animal cells and stem cell-derived tissues. The microcapsules that we have investigated are designed to immunoprotect islets of Langerhans (i.e. clusters of insulin-secreting cells), with the goal of treating insulin-dependent diabetes. With the aid of techniques for physicochemical analysis, this research focused on understanding which properties of the microcapsule are the most important for determining its biocompatibility. The objective of this work was to elucidate correlations between the chemical make-up, physicochemical properties, and in vivo biocompatibility of alginate-based microcapsules. Our approach was based on the hypothesis that the immune response to the microcapsules is governed by, and can therefore be controlled by, specific physicochemical properties of the microcapsule and its material components. The experimental work was divided into five phases, each associated with a specific aim : (1) To prove that immunoglobulins adsorb to the surface of alginate-polycation microcapsules, and to correlate this adsorption with the microcapsule chemistry. (2) To test interlaboratory reproducibility in making biocompatible microcapsules, and evaluate the suitability of our materials and fabrication protocols for subsequent studies. (3) To determine which physicochemical properties of alginates affect the in vivo biocompatibility of their gels. (4) To determine which physiochemical properties of alginate-polycation microcapsules are most important for determining their in vivo biocompatibility (5) To determine whether a modestly immunogenic membrane hinders or helps the ability of the microcapsule to immunoprotect islet xenografts in

  16. Biocompatible Ferromagnetic Cr-Trihalide Monolayers

    NASA Astrophysics Data System (ADS)

    Sun, Qiang

    Cr with an electronic configuration of 3d54s1 possesses the largest atomic magnetic moment (6µB) of all elements in the 3d transition metal series. Furthermore, the trivalent chromium (Cr3+) is biocompatible and is widely found in food and supplements. Here using first principles calculations combined with Monte Carlo simulations based on Ising model, we systematically study a class of 2D ferromagnetic monolayers CrX3 (X = Cl, Br, I). The feasibility of exfoliation from their layered bulk phase is confirmed by the small cleavage energy and high in-plane stiffness. Spin-polarized calculations, combined with self consistently determined Hubbard U that accounts for strong correlation energy, demonstrate that CrX3 (X =Cl, Br, I) monolayers are ferromagnetic and Cr is trivalent and carries a magnetic moment of 3µB, the resulting Cr3+ ions are biocompatible. The corresponding Curie temperatures for CrCl3 CrBr3 CrI3 are are found to 66, 86, and 107 K, respectively, which can be increased to 323, 314, 293 K by hole doping. The biocompatibility and ferromagnetism render these Cr-containing trichalcogenide monolayers unique for applications.

  17. Synthesis of microbial elastomers based on soybean oily acids. Biocompatibility studies.

    PubMed

    Hazer, Derya Burcu; Hazer, Baki; Kaymaz, Figen

    2009-06-01

    Biocompatibility studies of the autoxidized and unoxidized unsaturated medium-long chain length (m-lcl) co-poly-3-hydroxyalkanoates (m-lclPHAs) derived from soya oily acids have been reported. Pseudomonas oleovorans was grown on a series of mixtures of octanoic acid (OA) and soya oily acids (Sy) with weight ratios of 20:80, 28:72 and 50:50 in order to obtain unsaturated m-lcl copolyesters coded PHO-Sy-2080, PHO-Sy-2872 and PHO-Sy-5050, respectively. The PHA films were obtained by solvent cast from CHCl(3). They were all originally sticky and waxy except PHO-Sy-5050. Autoxidation of the unsaturated copolyester films was carried out on exposure to air at room temperature in order to obtain crosslinked polymers. They became a highly flexible elastomer after being autoxidized (about 40 days of autoxidation). The in vivo tissue reactions of the autoxidized PHAs were evaluated by subcutaneous implantation in rats. The rats appeared to be healthy throughout the implantation period. No symptom such as necrosis, abscess or tumorigenesis was observed in the vicinity of the implants. Retrieved materials varied in their physical appearance after 6 weeks of implantation. In vivo biocompatibility studies of the medical applications indicated that the microbial copolyesters obtained were all biocompatible and especially the PHOSy series of copolyesters had the highest biocompatibility among them. PMID:19498224

  18. The Biocompatibility of Porous vs Non-Porous Bone Cements: A New Methodological Approach

    PubMed Central

    Dall’Oca, C.; Maluta, T.; Cavani, F.; Morbioli, G.P.; Bernardi, P.; Sbarbati, A.; Degl’Innocenti, D.; Magnan, B.

    2014-01-01

    Composite cements have been shown to be biocompatible, bioactive, with good mechanical properties and capability to bind to the bone. Despite these interesting characteristic, in vivo studies on animal models are still incomplete and ultrastructural data are lacking. The acquisition of new ultrastructural data is hampered by uncertainties in the methods of preparation of histological samples due to the use of resins that melt methacrylate present in bone cement composition. A new porous acrylic cement composed of polymethyl-metacrylate (PMMA) and β-tricalcium-phosphate (p-TCP) was developed and tested on an animal model. The cement was implanted in femurs of 8 New Zealand White rabbits, which were observed for 8 weeks before their sacrifice. Histological samples were prepared with an infiltration process of LR white resin and then the specimens were studied by X-rays, histology and scanning electron microscopy (SEM). As a control, an acrylic standard cement, commonly used in clinical procedures, was chosen. Radiographic ultrastructural and histological exams have allowed finding an excellent biocompatibility of the new porous cement. The high degree of osteointegration was demonstrated by growth of neo-created bone tissue inside the cement sample. Local or systemic toxicity signs were not detected. The present work shows that the proposed procedure for the evaluation of biocompatibility, based on the use of LR white resin allows to make a thorough and objective assessment of the biocompatibility of porous and non-porous bone cements. PMID:24998920

  19. Readability and histological biocompatibility of microchip transponders in horses.

    PubMed

    Wulf, M; Wohlsein, P; Aurich, J E; Nees, M; Baumgärtner, W; Aurich, C

    2013-10-01

    Identification of horses by microchip transponder is mandatory within the European Union with only a few exceptions. In this study, the readability of such microchips in 428 horses with three different scanners (A, B and C) and the histological changes at the implantation site in 16 animals were assessed. Identification of microchips differed between scanners (P<0.001), and with 'side of neck' (P<0.001). Scanners A, B and C identified 93.5%, 89.7% and 100% of microchips, respectively, on the 'chip-bearing' side of the neck. From the contralateral side, scanners A, B and C identified 21.5%, 26.9% and 89.5% of transponders, respectively. Microchip readability was affected by age (P<0.001), but not by breed of horse. At necropsy, transponders were found in the subcutaneous fat (n=3), inter- or peri-muscular connective tissue (n=8), or musculature (n=5), where they were surrounded by a fibrous capsule ranging in thickness from 12.7 to 289.5 μm in 15 animals. In two animals, immature granulation tissue with attendant granulomatous inflammation, and a granulomatous myositis, surrounding the microchip were identified, respectively. Severe (n=1), moderate (n=1), and mild (n=3) lymphohistiocytic inflammation was noted within the fibrous capsule. Microchip transponders were found to be a highly reliable and biocompatible method of horse identification. PMID:23769456

  20. Biocompatibility of Intracanal Medications Based on Calcium Hydroxide

    PubMed Central

    Andolfatto, Carolina; da Silva, Guilherme Ferreira; Cornélio, Ana Livia Gomes; Guerreiro-Tanomaru, Juliane Maria; Tanomaru-Filho, Mario; Faria, Gisele; Bonetti-Filho, Idomeo; Cerri, Paulo Sérgio

    2012-01-01

    Objective. The aim of this study was to evaluate the rat subcutaneous tissue reaction to calcium hydroxide-based intracanal medicaments, UltraCal XS (calcium hydroxide, barium sulphate, aqueous matrix), Hydropast (calcium hydroxide, barium sulphate, and propyleneglycol), and Calen (Calcium hydroxide, zinc oxide, colophony, and polyethyleneglycol), used as a control. Methods. Forty-eight rats (Rattus Norvegicus Holtzman) were distributed in three groups: Calen, UltraCal XS, and Hydropast. Polyethylene tubes filled with one of the medicaments were implanted in the dorsal subcutaneous. After 7 and 30 days, the implants were removed and the specimens were fixed and embedded in paraffin. Morphological and quantitative analyses were carried out in the HE-stained sections. The numerical density of inflammatory cells in the capsule was evaluated and statistical analyses were performed (P ≤ 0.05). Results. At 7 days, all materials induced an inflammatory reaction in the subcutaneous tissue adjacent to the implants. In all groups, a significant reduction in the number of inflammatory cells and giant cells was verified in the period of 30 days. Conclusion. These results indicate that the calcium hydroxide-based medicaments evaluated present biocompatibility similar to Calen. PMID:23320187

  1. In vivo biocompatibility of the PLGA microparticles in parotid gland

    PubMed Central

    Cantín, Mario; Miranda, Patricio; Suazo Galdames, Iván; Zavando, Daniela; Arenas, Patricia; Velásquez, Luis; Vilos, Cristian

    2013-01-01

    Poly(lactic-co-glycolic acid) (PLGA) microparticles are used in various disorders for the controlled or sustained release of drugs, with the management of salivary gland pathologies possible using this technology. There is no record of the response to such microparticles in the glandular parenchyma. The purpose of this study was to assess the morphological changes in the parotid gland when injected with a single dose of PLGA microparticles. We used 12 adult female Sprague Dawley rats (Rattus norvegicus) that were injected into their right parotid gland with sterile vehicle solution (G1, n=4), 0.5 mg PLGA microparticles (G2, n=4), and 0.75 mg PLGA microparticles (G3, n=4); the microparticles were dissolved in a sterile vehicle solution. The intercalar and striated ducts lumen, the thickness of the acini and the histology aspect in terms of the parenchyma organization, cell morphology of acini and duct system, the presence of polymeric residues, and inflammatory response were determined at 14 days post-injection. The administration of the compound in a single dose modified some of the morphometric parameters of parenchyma (intercalar duct lumen and thickness of the glandular acini) but did not induce tissue inflammatory response, despite the visible presence of polymer waste. This suggests that PLGA microparticles are biocompatible with the parotid tissue, making it possible to use intraglandular controlled drug administration. PMID:24228103

  2. To evaluate the biocompatibility of the Indian Portland cement with potential for use in dentistry: An animal study

    PubMed Central

    Mangala, M G; Chandra, S M Sharath; Bhavle, Radhika M.

    2015-01-01

    Aims: This study evaluated the biocompatibility of the Indian Portland cement with potential for use in dentistry. Materials and Methods: This study was performed in Swiss albino mice, by implanting the Indian Portland cement pellets subcutaneously. After 1, 3, and 6 weeks the tissue specimens were prepared for histological examination. Results: The histological analysis showed moderate to severe inflammation at 1 week. The inflammation gradually decreased by 6 weeks, with most of the specimens showing the absence of inflammatory reaction. Conclusions: According to these experimental conditions, the tested Indian Portland cement was biocompatible. PMID:26752835

  3. Doped biocompatible layers prepared by laser

    NASA Astrophysics Data System (ADS)

    Jelínek, M.; Weiserová, M.; Kocourek, T.; Jurek, K.; Strnad, J.

    2010-03-01

    The contribution deals with KrF laser synthesis and study of doped biocompatible materials with focus on diamond-like carbon (DLC) and hydroxyapatite (HA). Overview of materials used for dopation is given. Experimental results of study of HA layers doped with silver are presented. Films properties were characterized using profilometer, SEM, WDX, XRD and optical transmission. Content of silver in layers moved from 0.06 to 13.7 at %. The antibacterial properties of HA, silver and doped HA layers were studied in vivo using Escherichia coli cells.

  4. Multifunctional biocompatible coatings on magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Bychkova, A. V.; Sorokina, O. N.; Rosenfeld, M. A.; Kovarski, A. L.

    2012-11-01

    Methods for coating formation on magnetic nanoparticles used in biology and medicine are considered. Key requirements to the coatings are formulated, namely, biocompatibility, stability, the possibility of attachment of pharmaceutical agents, and the absence of toxicity. The behaviour of nanoparticle/coating nanosystems in the body including penetration through cellular membranes and the excretion rates and routes is analyzed. Parameters characterizing the magnetic properties of these systems and their magnetic controllability are described. Factors limiting the applications of magnetically controlled nanosystems for targeted drug delivery are discussed. The bibliography includes 405 references.

  5. Surface properties and biocompatibility of nitrided titanium for abrasion resistant implant materials.

    PubMed

    Tamura, Yutaka; Yokoyama, Atsuro; Watari, Fumio; Kawasaki, Takao

    2002-12-01

    Corrosion, other related properties and biocompatibility of surface nitrided titanium were investigated to examine its possible use as an abrasion resistant implant material. The nitrided layer about 2 microm thick composed of TiN and Ti2N was formed on titanium by a gas nitriding method. The dissolved amount of titanium ion in SBF was as low as the detection limit of ICP, and that in the 1% lactic acid showed no significant difference from titanium. The tissue reaction of the cylindrical implant in soft tissue of rats showed no inflammation, and fine particles of 1 microm induced phagocytosis, which was similar to titanium. The implantation in the femor showed the new bone formed in direct contact with implants. All the results suggested that the wettability, corrosion resistance, S. mutans adhesion and biocompatibility were nearly equivalent to those of titanium. The surface of nitrided titanium was promising, with biocompatibility comparable with titanium, as an implant material such as for an abutment part of a dental implant, which requires high abrasion resistance. PMID:12608425

  6. Research on the preparation, biocompatibility and bioactivity of magnesium matrix hydroxyapatite composite material.

    PubMed

    Linsheng, Li; Guoxiang, Lin; Lihui, Li

    2016-08-12

    In this paper, magnesium matrix hydroxyapatite composite material was prepared by electrophoretic deposition method. The optimal process parameters of electrophoretic deposition were HA suspension concentration of 0.02 kg/L, aging time of 10 days and voltage of 60 V. Animal experiment and SBF immersion experiment were used to test the biocompatibility and bioactivity of this material respectively. The SD rats were divided into control group and implant group. The implant surrounding tissue was taken to do tissue biopsy, HE dyed and organizational analysis after a certain amount of time in the SD rat body. The biological composite material was soaked in SBF solution under homeothermic condition. After 40 days, the bioactivity of the biological composite material was evaluated by testing the growth ability of apatite on composite material. The experiment results showed that magnesium matrix hydroxyapatite biological composite material was successfully prepared by electrophoretic deposition method. Tissue hyperplasia, connective tissue and new blood vessels appeared in the implant surrounding soft tissue. No infiltration of inflammatory cells of lymphocytes and megakaryocytes around the implant was found. After soaked in SBF solution, a layer bone-like apatite was found on the surface of magnesium matrix hydroxyapatite biological composite material. The magnesium matrix hydroxyapatite biological composite material could promot calcium deposition and induce bone-like apatite formation with no cytotoxicity and good biocompatibility and bioactivity. PMID:27567779

  7. Biocompatibility of high-flux membranes.

    PubMed

    Putz, D; Barnas, U; Luger, A; Mayer, G; Woloszczuk, W; Graf, H

    1992-08-01

    Standard dialysis with cuprophane membranes is known to stimulate the immune system. As a result of activation of macrophages various interleukins and tumor necrosis factor (TNF) are secreted, presenting further evidence of the poor biocompatibility of cuprophane. We investigated the immunogenic properties of three modern high-flux membranes. Seven patients were studied during hemodiafiltration sessions using either a polysulfone (F60, Fresenius), a polymethylmetacrylate (BK 2.1, Toray) or a cellulose triacetate (FB-210 U, Nipro) dialyzer in a hemodiafiltration procedure. Serial measurements were made during each treatment of interleukin-1 beta (II-1 beta), TNF, soluble IL-2 receptor (sII-2r), soluble CD4 (sCD4), soluble CD8 (sCD8), interferon gamma (IFNg) and neopterin. In contrast to the known increase of IL-1 beta, IL-2r and TNF with cuprophane membranes, none of the modern high-flux dialyzers stimulated the production of these factors. Significant decreases of neopterin and sCD4 were observed. IFNg and sCD8 did not change significantly. Our results suggest that the modern high-flux dialyzers are non-immunogenic, and thus provide further evidence of the superior biocompatibility of synthetic or semisynthetic membranes over the conventional cuprophane. PMID:1399092

  8. Biocompatibility of platinum-metallized silicone rubber: in vivo and in vitro evaluation.

    PubMed

    Vince, V; Thil, M A; Veraart, C; Colin, I M; Delbeke, J

    2004-01-01

    Silicone rubber is commonly used for biomedical applications, including implanted cuff electrodes for both recording and stimulation of peripheral nerves. This study was undertaken to evaluate the consequences of a new platinum metallization method on the biocompatibility of silicone rubber cuff electrodes. This method was introduced in order to allow the manufacture of spiral nerve cuff electrodes with a large number of contacts. The metallization process, implying silicone coating with poly(methyl methacrylate) (PMMA), its activation by an excimer laser and subsequent electroless metal deposition, led to a new surface microtexture. The neutral red cytotoxicity assay procedure was first applied in vitro on BALB/c 3T3 fibroblasts in order to analyze the cellular response elicited by the studied material. An in vivo assay was then performed to investigate the tissue reaction after chronic subcutaneous implantation of the metallized material. Results demonstrate that silicone rubber biocompatibility is not altered by the new platinum metallization method. PMID:15109096

  9. Boron-Doped Nanocrystalline Diamond Electrodes for Neural Interfaces: In vivo Biocompatibility Evaluation.

    PubMed

    Alcaide, María; Taylor, Andrew; Fjorback, Morten; Zachar, Vladimir; Pennisi, Cristian P

    2016-01-01

    Boron-doped nanocrystalline diamond (BDD) electrodes have recently attracted attention as materials for neural electrodes due to their superior physical and electrochemical properties, however their biocompatibility remains largely unexplored. In this work, we aim to investigate the in vivo biocompatibility of BDD electrodes in relation to conventional titanium nitride (TiN) electrodes using a rat subcutaneous implantation model. High quality BDD films were synthesized on electrodes intended for use as an implantable neurostimulation device. After implantation for 2 and 4 weeks, tissue sections adjacent to the electrodes were obtained for histological analysis. Both types of implants were contained in a thin fibrous encapsulation layer, the thickness of which decreased with time. Although the level of neovascularization around the implants was similar, BDD electrodes elicited significantly thinner fibrous capsules and a milder inflammatory reaction at both time points. These results suggest that BDD films may constitute an appropriate material to support stable performance of implantable neural electrodes over time. PMID:27013949

  10. Development of a hydrophobic polymer composition with improved biocompatibility for making foldable intraocular lenses

    NASA Astrophysics Data System (ADS)

    Haldar, R. S.; Chauhan, R.; Kapoor, K.; Niyogi, U. K.

    2014-05-01

    A hydrophobic composition for foldable intraocular lenses was developed by copolymerizing phenyl ethyl acrylate, phenyl ethyl methacrylate and butanediol diacrylate by gamma irradiation. Aqueous solution of heparin, a biocompatibilizer absorbed in hydroxyethyl methacrylate was added to the monomer mixture before irradiation to impart desired level of hydrophilicity and improved biocompatibility to the hydrophobic composition. Ketorolac tromethamine, an anti-inflammatory agent and L-glutathione, an antioxidant were added to the composition as functional additive for exhibiting improved performance while in use. Concentrations of monomers, biocompatibilizer and functional additives were optimized to develop an advanced material for foldable intraocular lenses. Transmittance, refractive index, Abbe number, hardness, tensile strength, flexibility and foldability were studied on the final composition. Scanning electron microscopic study, differential scanning calorimetric analysis, leachability and viscometry confirmed the permanent incorporation of additives into the polymer. Results of haemocompatibility, tissue implantation and cytotoxicity confirm that the biocompatibility of the base polymer was improved by incorporation of heparin.

  11. Boron-Doped Nanocrystalline Diamond Electrodes for Neural Interfaces: In vivo Biocompatibility Evaluation

    PubMed Central

    Alcaide, María; Taylor, Andrew; Fjorback, Morten; Zachar, Vladimir; Pennisi, Cristian P.

    2016-01-01

    Boron-doped nanocrystalline diamond (BDD) electrodes have recently attracted attention as materials for neural electrodes due to their superior physical and electrochemical properties, however their biocompatibility remains largely unexplored. In this work, we aim to investigate the in vivo biocompatibility of BDD electrodes in relation to conventional titanium nitride (TiN) electrodes using a rat subcutaneous implantation model. High quality BDD films were synthesized on electrodes intended for use as an implantable neurostimulation device. After implantation for 2 and 4 weeks, tissue sections adjacent to the electrodes were obtained for histological analysis. Both types of implants were contained in a thin fibrous encapsulation layer, the thickness of which decreased with time. Although the level of neovascularization around the implants was similar, BDD electrodes elicited significantly thinner fibrous capsules and a milder inflammatory reaction at both time points. These results suggest that BDD films may constitute an appropriate material to support stable performance of implantable neural electrodes over time. PMID:27013949

  12. A Review of the Biocompatibility of Implantable Devices: Current Challenges to Overcome Foreign Body Response

    PubMed Central

    Onuki, Yoshinori; Bhardwaj, Upkar; Papadimitrakopoulos, Fotios; Burgess, Diane J.

    2008-01-01

    In recent years, a variety of devices (drug-eluting stents, artificial organs, biosensors, catheters, scaffolds for tissue engineering, heart valves, etc.) have been developed for implantation into patients. However, when such devices are implanted into the body, the body can react to these in a number of different ways. These reactions can result in an unexpected risk for patients. Therefore, it is important to assess and optimize the biocompatibility of implantable devices. To date, numerous strategies have been investigated to overcome body reactions induced by the implantation of devices. This review focuses on the foreign body response and the approaches that have been taken to overcome this. The biological response following device implantation and the methods for biocompatibility evaluation are summarized. Then the risks of implantable devices and the challenges to overcome these problems are introduced. Specifically, the challenges used to overcome the functional loss of glucose sensors, restenosis after stent implantation, and calcification induced by implantable devices are discussed. PMID:19885290

  13. [Electrochemical properties of biocompatible material hardness modifications on titanium and steel under mechanical loads].

    PubMed

    Braun, W; Walter, U; Holbein, R; Thull, R

    2005-04-01

    Friction corrosion may appear between different implant components or between implant and hard tissue. The sliding micro movements induce fretting wear corrosion and have been recently reported as a cause of joint prostheses failure. A surface coating is desirable, that retains the mechanical properties of the substrate, offers good biocompatibility and improves the fretting corrosion resistance. In this study it could be demonstrated that tantalum and niobium coatings fulfill the requirements. On titanium substrates the coating decreases the abrasion against PMMA, an orthopedic relevant material. Furthermore, in the case of medical steel substrates the biocompatibility and the corrosion properties are improved. The better abrasion-resistance is minimizing the release of allergological critical particles like nickel and chromium. PMID:15884706

  14. Chitin and carbon nanotube composites as biocompatible scaffolds for neuron growth

    NASA Astrophysics Data System (ADS)

    Singh, Nandita; Chen, Jinhu; Koziol, Krzysztof K.; Hallam, Keith R.; Janas, Dawid; Patil, Avinash J.; Strachan, Ally; G. Hanley, Jonathan; Rahatekar, Sameer S.

    2016-04-01

    The design of biocompatible implants for neuron repair/regeneration ideally requires high cell adhesion as well as good electrical conductivity. Here, we have shown that plasma-treated chitin carbon nanotube composite scaffolds show very good neuron adhesion as well as support of synaptic function of neurons. The addition of carbon nanotubes to a chitin biopolymer improved the electrical conductivity and the assisted oxygen plasma treatment introduced more oxygen species onto the chitin nanotube scaffold surface. Neuron viability experiments showed excellent neuron attachment onto plasma-treated chitin nanotube composite scaffolds. The support of synaptic function was evident on chitin/nanotube composites, as confirmed by PSD-95 staining. The biocompatible and electrically-conducting chitin nanotube composite scaffold prepared in this study can be used for in vitro tissue engineering of neurons and, potentially, as an implantable electrode for stimulation and repair of neurons.

  15. Biocompatibility evaluation of a thermoplastic rubber for wireless telemetric intracranial pressure sensor coating

    PubMed Central

    Yang, Jun; Charif, Andrea C.; Puskas, Judit E.; Phillips, Hannah; Shanahan, Kaitlyn J.; Garsed, Jessica; Fleischman, Aaron; Goldman, Ken; Luebbers, Matthew T.; Dombrowski, Stephen M.; Luciano, Mark G.

    2015-01-01

    This study investigated the biocompatibility of the experimental thermoplastic rubber Arbomatrix™ that will be used as the protective coating on a novel intracranial pressure (ICP) sensor silicon chip. Arbomatrix™ was benchmarked against biocompatible commercial silicone rubber shunt tubing in the brain via a rat model with 60-day implant duration. A bare silicon chip was also implanted. The results showed similar cellular distribution in the brain-implant boundary and surrounding tissues. Quantitative analysis of neuron and glia density did not show significant difference between implants. Through histological and immunohistochemical evaluation we conclude that Arbomatrix™ is well tolerated by the brain. Due to its exceptional barrier properties Arbomatrix™ has already been shown to be an excellent protective coating for new ICP monitoring chip. PMID:25688030

  16. Biocompatibility evaluation of a thermoplastic rubber for wireless telemetric intracranial pressure sensor coating.

    PubMed

    Yang, Jun; Charif, Andrea C; Puskas, Judit E; Phillips, Hannah; Shanahan, Kaitlyn J; Garsed, Jessica; Fleischman, Aaron; Goldman, Ken; Roy, Shuvo; Luebbers, Matthew T; Dombrowski, Stephen M; Luciano, Mark G

    2015-05-01

    This study investigated the biocompatibility of the experimental thermoplastic rubber Arbomatrix(™) that will be used as the protective coating on a novel intracranial pressure (ICP) sensor silicon chip. Arbomatrix(™) was benchmarked against biocompatible commercial silicone rubber shunt tubing in the brain via a rat model with 60-day implant duration. A bare silicon chip was also implanted. The results showed similar cellular distribution in the brain-implant boundary and surrounding tissues. Quantitative analysis of neuron and glia density did not show significant difference between implants. Through histological and immunohistochemical evaluation we conclude that Arbomatrix(™) is well tolerated by the brain. Due to its exceptional barrier properties Arbomatrix(™) has already been shown to be an excellent protective coating for new ICP monitoring chip. PMID:25688030

  17. BSA-directed synthesis of CuS nanoparticles as a biocompatible photothermal agent for tumor ablation in vivo.

    PubMed

    Zhang, Cai; Fu, Yan-Yan; Zhang, Xuejun; Yu, Chunshui; Zhao, Yan; Sun, Shao-Kai

    2015-08-01

    Photothermal therapy as a physical therapeutic approach has greatly attracted research interest due to its negligible systemic effects. Among the various photothermal agents, CuS nanoparticles have been widely used due to their easy preparation, low cost, high stability and strong absorption in the NIR region. However, the ambiguous biotoxicity of CuS nanoparticles limited their bio-application. So it is highly desirable to develop biocompatible CuS photothermal agents with the potential of clinical translation. Herein, we report a novel method to synthesize biocompatible CuS nanoparticles for photothermal therapy using bovine serum albumin (BSA) as a template via mimicking biomaterialization processes. Owing to the inherent biocompatibility of BSA, the toxicity assays in vitro and in vivo showed that BSA-CuS nanoparticles possessed good biocompatibility. In vitro and in vivo photothermal therapies were performed and good results were obtained. The bulk of the HeLa cells treated with BSA-CuS nanoparticles under laser irradiation (808 nm) were killed, and the tumor tissues of mice were also successfully eliminated without causing any obvious systemic damage. In summary, a novel strategy for the synthesis of CuS nanoparticles was developed using BSA as the template, and the excellent biocompatibility and efficient photothermal therapy effects of BSA-CuS nanoparticles show great potential as an ideal photothermal agent for cancer treatment. PMID:26106950

  18. A novel biocompatible conducting polyvinyl alcohol (PVA)-polyvinylpyrrolidone (PVP)-hydroxyapatite (HAP) composite scaffolds for probable biological application.

    PubMed

    Chaudhuri, B; Mondal, B; Ray, S K; Sarkar, S C

    2016-07-01

    We have prepared biocompatible composites of 80wt% polyvinyl alcohol (PVA)-(20wt%) polyvinylpyrrolidone (PVP) blend with different concentrations of bioactive nanohydroxyapatite, Ca10(PO4)6(HO)2 (HAP). The composite films demonstrated maximum effective conductivity (σ∼1.64×10(-4)S/m) and effective dielectric constant (ε∼290) at percolation threshold concentration (∼10wt% HAP) at room temperature. These values of σ and ε are much higher than those of PVA, PVP or HAP. Our preliminary observation indicated excellent biocompatibility of the electrospun fibrous meshes of two of these composites with different HAP contents (8.5 and 5wt% within percolation threshold concentration) using NIH 3T3 fibroblast cell line. Cells viability on the well characterized composite fibrous scaffolds was determined by MTT [3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay analysis. Enhancement of σ, due to HAP addition, was found to show increased biocompatibility of the fibrous scaffold. Enhanced σ value of the PVA/PVP-HAP composite provided supporting cues for the increased cell viability and biocompatibility of the composite fibrous meshes. Excellent biocompatibility these electrospun composite scaffolds made them to plausible potential candidates for tissue engineering or other biomedical applications. PMID:26998868

  19. Tuning the Friction Characteristics of Gecko-Inspired Polydimethylsiloxane Micropillar Arrays by Embedding Fe₃O₄ and SiO₂ Particles.

    PubMed

    Tian, Ye; Zhao, Zizhou; Zaghi, Gina; Kim, Yongkwan; Zhang, Dongxing; Maboudian, Roya

    2015-06-24

    In order to improve stiffness of polydimethylsiloxane (PDMS) pillars while maintaining high friction, the effects of embedding Fe3O4 and SiO2 particles on the friction behavior of PDMS micropillars are studied. Both types of added particles increase the stiffness of the PDMS composite, but affect the friction behavior differently. The frictional force of the fibrillar array fabricated with Fe3O4/PDMS composite decreases initially, then increases as the particle content increases. For silica/PDMS composite pillars, the frictional force is independent of the particle density. Characterization by scanning electron microscopy shows that Fe3O4 particles are distributed uniformly in the PDMS matrix at low concentration, but heterogeneous distribution is observed at high particle loading, with particles being hindered from penetrating into the pillars. For silica/PDMS composite pillars, the particles distribute homogeneously inside the pillars, which is attributed to the formation of hydrogen bonding between silica particles and PDMS. The difference in particle distribution behavior is used to explain the observed difference in the friction response of these two composite systems. PMID:26042962

  20. Titanium nanostructural surface processing for improved biocompatibility

    SciTech Connect

    Cheng, H.-C.; Lee, S.-Y.; Chen, C.-C.; Shyng, Y.-C.; Ou, K.-L.

    2006-10-23

    X-ray photoelectron spectroscopy, grazing incident x-ray diffraction, transmission electron microscopy, and scanning electron microscopy were conducted to evaluate the effect of titanium hydride on the formation of nanoporous TiO{sub 2} on Ti during anodization. Nano-titanium-hydride was formed cathodically before anodizing and served as a sacrificial nanoprecipitate during anodization. Surface oxidation occurred and a multinanoporous structure formed after cathodic pretreatments followed by anodization treatment. The sacrificial nanoprecipitate is directly dissolved and the Ti transformed to nanoporous TiO{sub 2} by anodization. The formation of sacrificial nanoprecipitates by cathodic pretreatment and of the multinanostructure by anodization is believed to improve biocompatibility, thereby promoting osseointegration.

  1. Biostability and biocompatibility of modified polyurethane elastomers

    NASA Astrophysics Data System (ADS)

    Christenson, Elizabeth Marie

    Several strategies have been employed to increase the biostability of medical grade polyurethanes while maintaining the desirable properties of current poly(ether urethanes). It was hypothesized that polyurethane surface chemistry controls biodegradation/biostability that can lead to ultimate failure/success of these materials in clinical applications. Chemical modification or replacement of the susceptible soft segment was evaluated as a design strategy to increase the biostability of medical grade polyurethanes. The effect of soft segment chemistry on the phase morphology, mechanical properties and in vivo response of commercial polyurethanes were compared. Poly(ether urethane) (PEU), silicone-modified poly(ether urethane) (PEU-S), poly(carbonate urethane) (PCU) and silicone-modified poly(carbonate urethane) (PCU-S) elastomers were investigated. AFM phase imaging indicated that the overall two-phase morphology of poly(ether urethanes), necessary for its thermoplastic elastomeric properties, was not disrupted by changing the soft segment chemistry. All of the polyurethanes exhibited thermoplastic elastomeric behavior similar to that of the poly(ether urethane). Following material characterization, the biocompatibility of the polyurethane elastomers was evaluated using a subcutaneous cage implant protocol. All of the polyurethanes tested retained the excellent biocompatibility typical of poly(ether urethane) elastomers. Overall, the candidate polyurethanes were concluded to be suitable replacements of current poly(ether urethane) elastomers in medical applications. The results from the cage implant study and cell culture experiments indicated that monocytes adhere, differentiate and fuse to form foreign body giant cells (FBGCs) on all of the polyurethane specimens. It is now generally accepted that the reactive oxygen species released by these adherent macrophages and FBGCs initiate PEU biodegradation. ATR-FTIR analysis of explanted samples provided evidence of

  2. Conversion of bulk seashells to biocompatible hydroxyapatite for bone implants.

    PubMed

    Vecchio, Kenneth S; Zhang, Xing; Massie, Jennifer B; Wang, Mark; Kim, Choll W

    2007-11-01

    Strombus gigas (conch) shells and Tridacna gigas (Giant clam) shells have dense, tailored structures that impart excellent mechanical properties to these shells. In this investigation, conch and clam seashells were converted to hydroxyapatite (HAP) by a hydrothermal method at different temperatures and for different conversion durations. Dense HAP structures were created from these shells throughout the majority of the samples at the relative low temperature of approximately 200 degrees C. The average fracture stress was found to be approximately 137-218MPa for partially converted conch shell samples and approximately 70-150MPa for original and converted clamshell samples, which is close to the mechanical strength of compact human bone. This indicates that the converted shell samples can be used as implants in load-bearing cases. In vivo tests of converted shell samples were performed in rat femoral defects for 6 weeks. The microtomography images at 6 weeks show that the implants did not move, and untreated control defects remain empty with no evidence of a spontaneous fusion. Histological study reveals that there is newly formed bone growing up to and around the implants. There is no evidence of a fibrosis tissue ring around the implants, also indicating that there is no loosening of the implants. In contrast, the untreated controls remain empty with some evidence of a fibrosis ring around the defect hole. These results indicate good biocompatibility and bioactivity of the converted shell implants. PMID:17684000

  3. Biocompatibility of natural latex implanted into dental alveolus of rats.

    PubMed

    Balabanian, Cláudia A C A; Coutinho-Netto, Joaquim; Lamano-Carvalho, Teresa L; Lacerda, Suzie A; Brentegani, Luiz G

    2006-12-01

    The present study investigated the biocompatibility of a biopolymer based on vegetable latex extracted from the Hevea brasiliensis rubber tree, implanted into the bony alveolar cavity after dental extraction in rats. A granule of latex (area = 0.25 +/- 0.04 mm(2)) was implanted inside the alveolus immediately after extraction of the upper right incisor, and the animals were sacrificed 7, 21 and 42 days after the procedure. The hemi-maxillas were decalcified and processed for embedding in paraffin to obtain semi-serial longitudinal sections 5 mum thick, and then stained with hematoxylin-eosin. The latex granule was observed in the cervical third of the alveolus without any foreign body reaction, or persistence of the initial acute inflammatory reaction. Bone repair in the areas adjacent to the material was quantified, and a decrease was noted in the thickness of the fibrous capsule surrounding the implants from 92.8 +/- 9.3 microm on day 7 to 9.4 +/- 1.8 microm on day 42 (ANOVA, P = 0.01). The quantitative data confirmed acceleration of bone formation (statistically significant at 5%) in parallel with a decrease of connective tissue in the areas around the implants. These results show that the tested material is biologically compatible, and progressively integrated into the alveolar bone, simultaneously accelerating bone formation and playing an important role in the healing process. PMID:17220617

  4. Solution behavior of PEO : the ultimate biocompatible polymer.

    SciTech Connect

    Curro, John G.; Frischknecht, Amalie Lucile

    2004-11-01

    Poly(ethylene oxide) (PEO) is the quintessential biocompatible polymer. Due to its ability to form hydrogen bonds, it is soluble in water, and yet is uncharged and relatively inert. It is being investigated for use in a wide range of biomedical and biotechnical applications, including the prevention of protein adhesion (biofouling), controlled drug delivery, and tissue scaffolds. PEO has also been proposed for use in novel polymer hydrogel nanocomposites with superior mechanical properties. However, the phase behavior of PEO in water is highly anomalous and is not addressed by current theories of polymer solutions. The effective interactions between PEO and water are very concentration dependent, unlike other polymer/solvent systems, due to water-water and water-PEO hydrogen bonds. An understanding of this anomalous behavior requires a careful examination of PEO liquids and solutions on the molecular level. We performed massively parallel molecular dynamics simulations and self-consistent Polymer Reference Interaction Site Model (PRISM) calculations on PEO liquids. We also initiated MD studies on PEO/water solutions with and without an applied electric field. This work is summarized in three parts devoted to: (1) A comparison of MD simulations, theory and experiment on PEO liquids; (2) The implementation of water potentials into the LAMMPS MD code; and (3) A theoretical analysis of the effect of an applied electric field on the phase diagram of polymer solutions.

  5. Biocompatible Mesoporous Nanotubular Structured Surface to Control Cell Behaviors and Deliver Bioactive Molecules.

    PubMed

    Patel, Kapil D; Mahapatra, Chinmaya; Jin, Guang-Zhen; Singh, Rajendra K; Kim, Hae-Won

    2015-12-01

    Biocompatible nanostructured surfaces control the cell behaviors and tissue integration process of medical devices and implants. Here we develop a novel biocompatible nanostructured surface based on mesoporous silica nanotube (MSNT) by means of an electrodeposition. MSNTs, replicated from carbon nanotubes of 25 nm × 1200 nm size, were interfaced in combination with fugitive biopolymers (chitosan or collagen) onto a Ti metallic substrate. The MSNT-biopolymer deposits uniformly covered the substrate with weight gains controllable by the electrodeposition conditions. Random nanotubular networks were generated successfully, which alongside the high mesoporosity provided unique nanotopological properties for the cell responses and the loading/delivery of biomolecules. Of note, the adhesion and spreading behaviors of mesenchymal stem cells (MSCs) were significantly altered, revealing more rapid cell anchorage and extensive nanofilopodia development along the nanotubular networks. Furthermore, the nanotubular surface improved the loading capacity of biomolecules (dexamethasone and bovine serum albumin) up to 5-7 times. The release of the biomolecules was highly sustained, exhibiting a diffusion-controlled pattern over 15 days. The therapeutic efficacy of the delivered biomolecules was also confirmed in the osteogenic differentiation of MSCs. While in vivo performance and applicability studies are needed further, the current biocompatible nanostructured surface may be considered as a novel biointerfacing platform to control cellular behaviors and biomolecular delivery. PMID:26561865

  6. Well-defined and biocompatible hydrogels with toughening and reversible photoresponsive properties.

    PubMed

    Sun, Zhiqiang; Liu, Shunli; Li, Kewen; Tan, Linhua; Cen, Lian; Fu, Guodong

    2016-02-21

    In the present study, novel hydrogels with extremely high strength, reversible photoresponsive and excellent biocompatible properties were prepared. The functional hydrogels were synthesized from a well-defined poly (ethylene glycol) polymer with spiropyran groups at a given position (PEG-SP) via a Cu(i)-catalyst Azide-Alkyne Cycloaddition (CuAAC) reaction. The molecular structures of the sequential intermediates for PEG-SP hydrogel preparation were verified by (1)HNMR and FT-IR. The mechanical property, swelling ratio, compression strength, surface hydrophilicity, and biocompatibility of the resulting hydrogel were characterized. Since spiropyran is pivotal to the switch in hydrophilicity on the hydrogel surface, the swelling ratio of PEG-SP hydrogel under Vis irradiation has a major decrease (155%). Before and after UV light irradiation, the contact angle of the hydrogel has a change of 13.8°. The photoresponsive property of this hydrogel was thus demonstrated, and such a property was also shown to be reversible. The well-defined PEG-SP hydrogel can also sustain a compressive stress of 49.8 MPa without any macro- or micro-damage, indicating its outstanding mechanical performance. Furthermore, it possessed excellent biocompatibility as demonstrated by its performance in an in vivo porcine subcutaneous implantation environment. No inflammation was observed and it got along well with the adjacent tissue. The above features indicate that PEG-SP hydrogels are promising as an implantable matrix for potential applications in biomaterial. PMID:26744299

  7. Ocular biocompatibility of carbodiimide cross-linked hyaluronic acid hydrogels for cell sheet delivery carriers.

    PubMed

    Lai, Jui-Yang; Ma, David Hui-Kang; Cheng, Hsiao-Yun; Sun, Chi-Chin; Huang, Shu-Jung; Li, Ya-Ting; Hsiue, Ging-Ho

    2010-01-01

    Due to its innocuous nature, hyaluronic acid (HA) is one of the most commonly used biopolymers for ophthalmic applications. We recently developed a cell sheet delivery system using carbodiimide cross-linked HA carriers. Chemical cross-linking provides an improvement in stability of polymer gels, but probably causes toxic side-effects. The aim of this study was to investigate the ocular biocompatibility of HA hydrogels cross-linked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC). HA discs without cross-linking and glutaraldehyde (GTA) cross-linked HA samples were used for comparison. The disc implants were inserted in the anterior chamber of rabbit eyes for 24 weeks and characterized by slit-lamp biomicroscopy, histology and scanning electron microscopy. The ophthalmic parameters obtained from biomicroscopic examinations were also scored to provide a quantitative grading system. Results of this study showed that the HA discs cross-linked with EDC had better ocular biocompatibility than those with GTA. The continued residence of GTA cross-linked HA implants in the intraocular cavity elicited severe tissue responses and significant foreign body reactions, whereas no adverse inflammatory reaction was observed after contact with non-cross-linked HA or EDC cross-linked HA samples. It is concluded that the cross-linking agent type gives influence on ocular biocompatibility of cell carriers and the EDC-HA hydrogel is an ideal candidate for use as an implantable material in cell sheet delivery applications. PMID:20178691

  8. In Vivo Skeletal Muscle Biocompatibility of Composite, Coaxial Electrospun, and Microfibrous Scaffolds

    PubMed Central

    McKeon-Fischer, Kristin D.; Rossmeisl, John H.; Whittington, Abby R.

    2014-01-01

    One weakness with currently researched skeletal muscle tissue replacement is the lack of contraction and relaxation during the regenerative process. A biocompatible scaffold that can act similar to the muscle would be a pivotal innovation. Coaxial electrospun scaffolds, capable of movement with electrical stimulation, were created using poly(ɛ-caprolactone) (PCL), multiwalled carbon nanotubes (MWCNT), and a (83/17 or 40/60) poly(acrylic acid)/poly(vinyl alcohol) (PAA/PVA) hydrogel. The two scaffolds were implanted into Sprague-Dawley rat vastus lateralis muscle and compared with a phosphate-buffered saline injection sham surgery and an unoperated control. No complications or adverse effects were observed. Rats were sacrificed on days 7, 14, 21, and 28 postimplantation and biocompatibility assessed using enzymatic activity, fibrosis formation, inflammation, scaffold cellular infiltration, and neovascularization. Serum creatine kinase and lactate dehydrogenase levels were significantly higher in scaffold-implanted rats compared with the control on day 7, but returned to baseline by day 14. Day 7 scaffolds showed significant inflammation and fibrosis that decreased over time. Fibroblasts infiltrated the scaffolds early, but decreased with time, while myogenic cell numbers increased. Neovascularization of both scaffolds occurred as early as day 7. We conclude that the PCL-MWCNT-PAA/PVA scaffolds are biocompatible and suitable for muscle regeneration as myogenic cell growth was supported. PMID:24471815

  9. In vivo skeletal muscle biocompatibility of composite, coaxial electrospun, and microfibrous scaffolds.

    PubMed

    McKeon-Fischer, Kristin D; Rossmeisl, John H; Whittington, Abby R; Freeman, Joseph W

    2014-07-01

    One weakness with currently researched skeletal muscle tissue replacement is the lack of contraction and relaxation during the regenerative process. A biocompatible scaffold that can act similar to the muscle would be a pivotal innovation. Coaxial electrospun scaffolds, capable of movement with electrical stimulation, were created using poly(ɛ-caprolactone) (PCL), multiwalled carbon nanotubes (MWCNT), and a (83/17 or 40/60) poly(acrylic acid)/poly(vinyl alcohol) (PAA/PVA) hydrogel. The two scaffolds were implanted into Sprague-Dawley rat vastus lateralis muscle and compared with a phosphate-buffered saline injection sham surgery and an unoperated control. No complications or adverse effects were observed. Rats were sacrificed on days 7, 14, 21, and 28 postimplantation and biocompatibility assessed using enzymatic activity, fibrosis formation, inflammation, scaffold cellular infiltration, and neovascularization. Serum creatine kinase and lactate dehydrogenase levels were significantly higher in scaffold-implanted rats compared with the control on day 7, but returned to baseline by day 14. Day 7 scaffolds showed significant inflammation and fibrosis that decreased over time. Fibroblasts infiltrated the scaffolds early, but decreased with time, while myogenic cell numbers increased. Neovascularization of both scaffolds occurred as early as day 7. We conclude that the PCL-MWCNT-PAA/PVA scaffolds are biocompatible and suitable for muscle regeneration as myogenic cell growth was supported. PMID:24471815

  10. Influence of surface modification on corrosion and biocompatibility of titanium alloys

    NASA Astrophysics Data System (ADS)

    Rahman, Zia Ur

    Titanium alloys are playing a vital role in the field of biomaterials due to their excellent corrosion resistance and biocompatibility. These alloys enhance the quality and longevity of human life by replacing or treating various parts of the body. However, as these materials are in constant contact with the aggressive body fluids, corrosion leads to metal ions dissolution. These ions leach to the adjacent tissues and causes adverse reactions. Surface modifications are used to improve corrosion resistance and biological activity without changing their bulk properties. In this investigation, electropolishing, magnetoelectropolishing, titanium coating and hydroxiapatitecoating were carried out on commercially pure titanium (CPTi), Ti6Al4V and Ti6Al4V-ELI (Extra Low Interstitials). These surface modifications are known to effect surface charge, chemistry, morphology; wettability, corrosion resistance and biocompatibility of these materials. In vitro cyclic potentiodynamic polarization tests were conducted in phosphate buffer saline in compliance with ASTM standard. The surface morphology, roughness and wettability of these alloys were studied using scanning electron microscope, atomic force microscope and contact angle meter, respectively. Moreover, biocompatibility of titanium alloys was assessed by growing MC3T3 pre-osteoblast cells on their surfaces

  11. Influence of Electropolishing and Magnetoelectropolishing on Corrosion and Biocompatibility of Titanium Implants

    NASA Astrophysics Data System (ADS)

    Rahman, Zia ur; Pompa, Luis; Haider, Waseem

    2014-11-01

    Titanium alloys are playing a vital role in the field of biomaterials due to their excellent corrosion resistance and biocompatibility. These alloys enhance the quality and longevity of human life by replacing or treating various parts of the body. However, as these materials are in constant contact with the aggressive body fluids, corrosion of these alloys leads to metal ions release. These ions leach to the adjacent tissues and result in adverse biological reactions and mechanical failure of implant. Surface modifications are used to improve corrosion resistance and biological activity without changing their bulk properties. In this investigation, electropolishing and magnetoelectropolishing were carried out on commercially pure titanium, Ti6Al4V, and Ti6Al4V-ELI. These surface modifications are known to effect surface charge, chemistry, morphology; wettability, corrosion resistance, and biocompatibility of these materials. In vitro cyclic potentiodynamic polarization tests were conducted in phosphate buffer saline in compliance with ASTM standard F-2129-12. The surface morphology, roughness, and wettability of these alloys were studied using scanning electron microscope, atomic force microscope, and contact angle meter, respectively. Moreover, biocompatibility of titanium alloys was assessed by growing MC3T3 pre-osteoblast cells on them.

  12. Hancornia speciosa latex for biomedical applications: physical and chemical properties, biocompatibility assessment and angiogenic activity.

    PubMed

    Almeida, Luciane Madureira; Floriano, Juliana Ferreira; Ribeiro, Thuanne Pires; Magno, Lais Nogueira; da Mota, Lígia Souza Lima Silveira; Peixoto, Nei; Mrué, Fátima; Melo-Reis, Paulo; Lino Junior, Ruy de Souza; Graeff, Carlos Frederico de Oliveira; Gonçalves, Pablo José

    2014-09-01

    The latex obtained from Hancornia speciosa is used in folk medicine for treatment of several diseases, such as acne, warts, diabetes, gastritis and inflammation. In this work, we describe the biocompatibility assessment and angiogenic properties of H. speciosa latex and its potential application in medicine. The physical-chemical characterization was carried out following different methodologies (CHN elemental analyses; thermogravimetric analyses and Fourier transform infrared spectroscopy). The biocompatibility was evaluated through cytotoxicity and genotoxicity tests in fibroblast mouse cells and the angiogenic properties were evaluated using the chick chorioallantoic membrane (CAM) assay model. The physical-chemical results showed that the structure of Hancornia speciosa latex biomembrane is very similar to that of Hevea brasiliensis (commercially available product). Moreover, the cytotoxicity and genotoxicity assays showed that H. speciosa latex is biocompatible with life systems and can be a good biomaterial for medical applications. The CAM test showed the efficient ability of H. speciosa latex in neovascularization of tissues. The histological analysis was in accordance with the results obtained in the CAM assay. Our data indicate that the latex obtained from H. speciosa and eluted in water showed significant angiogenic activity without any cytotoxic or genotoxic effects on life systems. The same did not occur with H. speciosa latex stabilized with ammonia. Addition of ammonia does not have significant effects on the structure of biomembranes, but showed a smaller cell survival and a significant genotoxicity effect. This study contributes to the understanding of the potentialities of H. speciosa latex as a source of new phytomedicines. PMID:24973907

  13. An in vivo study of the biocompatibility of classic and novel device materials on the central nervous system

    NASA Astrophysics Data System (ADS)

    Jaboro, Claudine

    2007-12-01

    Investigation of novel biomaterials is an essential part of the development of electrical stimulation and chemical drug delivery for biomedical applications. In evaluating biocompatibility, the material's surface and the tissue should both be analyzed to determine their interaction during neural exposure. This includes a material investigation of bulk sapphire substrate, platinum (Pt) deposited on sapphire substrate using magnetron sputtering and aluminum nitride (AlN) which was deposited on sapphire substrate using plasma source molecular beam epitaxy (PSMBE). Zinc titania coverslip glass and borosilicate glass were used as control materials. The materials were implanted for periods of 10, 28 and 90 days on the cortical surface of the brain in a rat animal model. The chronic implants were analyzed both pre- and post- implantation for device structure/tissue interactions down to the atomic level. The characterization techniques used to explore structural and chemical changes on or within the material included optical microscopy, atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). Magnetic Resonance Imaging (MRI) and histology were used to determine the effects of the implants in vivo. Biocompatibility is the ability of a material or device to be exposed to the dynamic environment of the body and elicit little or no adverse effects. The data suggests that the biocompatibility of a material may be directly associated with structure and topology. The sapphire, zinc titania coverslip glass and platinum all had signs of bio-incompatibility. The aluminum nitride and borosilicate glass materials were both biocompatible based on our studies. The borosilicate glass elicited no response from the tissue while the aluminum nitride had a positive affect on the tissue encouraging the attachment of proteins and tissue without glial scars instigation. The material characterization, MR imaging and histological data show that surface features such as roughness

  14. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)-based scaffolds for tissue engineering

    PubMed Central

    Chang, H.M.; Wang, Z.H.; Luo, H.N.; Xu, M.; Ren, X.Y.; Zheng, G.X.; Wu, B.J.; Zhang, X.H.; Lu, X.Y.; Chen, F.; Jing, X.H.; Wang, L.

    2014-01-01

    Development and selection of an ideal scaffold is of importance for tissue engineering. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a biocompatible bioresorbable copolymer that belongs to the polyhydroxyalkanoate family. Because of its good biocompatibility, PHBHHx has been widely used as a cell scaffold for tissue engineering. This review focuses on the utilization of PHBHHx-based scaffolds in tissue engineering. Advances in the preparation, modification, and application of PHBHHx scaffolds are discussed. PMID:25003631

  15. A new strategy for the decellularisation of large equine tendons as biocompatible tendon substitutes.

    PubMed

    Bottagisio, M; Pellegata, A F; Boschetti, F; Ferroni, M; Moretti, M; Lovati, A B

    2016-01-01

    Tendon ruptures and/or large losses remain to be a great clinical challenge and often require full replacement of the damaged tissue. The use of auto- and allografts or engineered scaffolds is an established approach to restore severe tendon injuries. However, these grafts are commonly related to scarce biocompatibility, site morbidity, chronic inflammation and poor biomechanical properties. Recently, the decellularisation techniques of allo- or xenografts using specific detergents have been studied and have been found to generate biocompatible substitutes that resemble the native tissue. This study aims to identify a novel decellularisation protocol for large equine tendons that would produce an extracellular matrix scaffold suitable for the regeneration of injured tendons in humans. Specifically, equine tendons were treated either with tri (n-butyl) phosphate alone, or associated to multiple concentrations of peracetic acid (1, 3 and 5 %), which has never before been tested in vitro.Samples were then analysed by histology and with biochemical, biomechanical, and cytotoxicity tests. The best decellularisation protocol, resulting from these examinations, was selected and the chosen scaffold was re-seeded with murine fibroblasts. Resulting grafts were tested for cell viability, histologic analysis, DNA and collagen content. The results identified 1 % tri (n-butyl) phosphate combined with 3 % peracetic acid as the most suitable decellularised matrix in terms of biochemical and biomechanical properties. Moreover, the non-cytotoxic nature of the decellularised matrix allowed for good fibroblast reseeding, thus demonstrating a biocompatible matrix that will be suitable for tendon tissue engineering and hopefully as substitutes in severe tendon damages. PMID:27386840

  16. Biocompatibility of single-walled carbon nanotube composites for bone regeneration

    PubMed Central

    Gupta, A.; Liberati, T. A.; Verhulst, S. J.; Main, B. J.; Roberts, M. H.; Potty, A. G. R.; Pylawka, T. K.; El-Amin III, S. F.

    2015-01-01

    Objectives The purpose of this study was to evaluate in vivo biocompatibility of novel single-walled carbon nanotubes (SWCNT)/poly(lactic-co-glycolic acid) (PLAGA) composites for applications in bone and tissue regeneration. Methods A total of 60 Sprague-Dawley rats (125 g to 149 g) were implanted subcutaneously with SWCNT/PLAGA composites (10 mg SWCNT and 1gm PLAGA 12 mm diameter two-dimensional disks), and at two, four, eight and 12 weeks post-implantation were compared with control (Sham) and PLAGA (five rats per group/point in time). Rats were observed for signs of morbidity, overt toxicity, weight gain and food consumption, while haematology, urinalysis and histopathology were completed when the animals were killed. Results No mortality and clinical signs were observed. All groups showed consistent weight gain, and the rate of gain for each group was similar. All groups exhibited a similar pattern for food consumption. No difference in urinalysis, haematology, and absolute and relative organ weight was observed. A mild to moderate increase in the summary toxicity (sumtox) score was observed for PLAGA and SWCNT/PLAGA implanted animals, whereas the control animals did not show any response. Both PLAGA and SWCNT/PLAGA showed a significantly higher sumtox score compared with the control group at all time intervals. However, there was no significant difference between PLAGA and SWCNT/PLAGA groups. Conclusions Our results demonstrate that SWCNT/PLAGA composites exhibited in vivo biocompatibility similar to the Food and Drug Administration approved biocompatible polymer, PLAGA, over a period of 12 weeks. These results showed potential of SWCNT/PLAGA composites for bone regeneration as the low percentage of SWCNT did not elicit a localised or general overt toxicity. Following the 12-week exposure, the material was considered to have an acceptable biocompatibility to warrant further long-term and more invasive in vivo studies. Cite this article: Bone Joint Res 2015

  17. In Vitro Study of Biocompatibility and Toxicity of Magnesium Nanomaterials for Biodegradable Implants

    NASA Astrophysics Data System (ADS)

    Pallavi, Manishi

    Biodegradable magnesium (Mg) has a great potential to be used as a next generation implant material for orthopedic applications due to its mechanical and osseointegration properties. However, surface characteristics, biocompatibility and toxicity of the released corrosion products, in the form of magnesium oxide (MgO) and magnesium hydroxide (Mg (OH)2) nanoparticles (NPs), at the junction of implants, and their surrounding tissues is not completely understood. Therefore, our goal was to identify in vitro biocompatibility, and toxicity of magnesium nanomaterials in osteoblast cells to mimic the in vivo environment for biodegradable implants. We hypothesized that the release of hydroxide ion (OH-) from MgO/ Mg(OH) 2 NPs will increase the corrosion behavior of these particles in osteoblast cells, and will introduce cytotoxicity. Therefore, the objective of this study was to characterize MgO/ Mg(OH)2 NPs in osteoblast cells, and to develop an electric cell-substrate impedance sensing (ECIS) system to measure the biocompatibility and toxicity of these particles in osteoblast cells. The corrosion behavior of the samples was analyzed through immersion test. The morphological characterization and element distribution of the surface corrosion products of the samples was performed using scanning electron microscopy (SEM) and electron dispersive X-ray spectroscopy (EDX), respectively. Cell viability and cytotoxicity of the samples was studied by live-dead assay. With ECIS system, biocompatibility and cytotoxicity of the samples was analyzed. Results shows that less than or equal to 1 mM concentrations of MgO/ Mg(OH) 2 NPs has negligible toxic effects on osteoblast cells. Therefore, this study provides a foundational knowledge for an acceptable range of these corrosion products that might release from the magnesium-based implants in the physiological environment, in order to understand the implant degradation for future in vivo study.

  18. In vivo biocompatibility of Resilon compared with gutta-percha in a pre-clinical model

    PubMed Central

    Cardoso, Miguel; Marques, Rodrigo F; Lopes, Maria Francelina; Cabrita, António S; Santos, João Miguel

    2013-01-01

    Background: The aim of this study was to investigate in vivo biocompatibility of Resilon, compared with gutta-percha, at short and long-term following implantation in a rat subcutaneous implantation model. Materials and Methods: Male Wistar rats were implanted subcutaneously with either Resilon or gutta-percha or were sham controls. Tissues were harvested at 8 days or 60 days after implantation and were evaluated histologically for inflammation and fibrous encapsulation. The severity of histologic injury, scored on a scale of 0-4 and quantitative analysis of the capsule wall thickness were determined for statistical analysis. Data were analyzed by Student t-test, one-way analysis of variance, Kruskal-Wallis or Mann-Whitney's tests as appropriate. A value of P ≤ 0.05 was considered statistically significant. Results: No behavioral changes or visible signs of physical impairment were observed at 8 days or 60 days post-implantation. Histopathologic observation of the implanted sites at each time-point showed that both Resilon and gutta-percha implants induced foreign body reaction, showing minimal to mild inflammatory reactions in most cases, which diminished significantly with time. Compared with gutta-percha, the capsule wall was thinner (P < 0.05) after Resilon implantation at day 8 and significantly (P = 0.01) thicker at day 60. In addition, capsule wall thickness showed a trend to increase with time after implantation in the Resilon groups (P < 0.05), opposed to the significant decrease (P = 0.016) observed after implantation in the gutta-percha groups, suggesting lesser long-term biocompatibility of Resilon. Conclusion: Our findings validate Resilon as an in vivo biocompatible material. However, our data suggest that long-term biocompatibility of Resilon, despite validated, is inferior to that of gutta-percha control. PMID:24348625

  19. In vitro and in vivo biocompatibility study on laser 3D microstructurable polymers

    NASA Astrophysics Data System (ADS)

    Malinauskas, Mangirdas; Baltriukiene, Daiva; Kraniauskas, Antanas; Danilevicius, Paulius; Jarasiene, Rasa; Sirmenis, Raimondas; Zukauskas, Albertas; Balciunas, Evaldas; Purlys, Vytautas; Gadonas, Roaldas; Bukelskiene, Virginija; Sirvydis, Vytautas; Piskarskas, Algis

    2012-09-01

    Films and microstructured scaffolds have been fabricated using direct laser writing out of different polymers: hybrid organic-inorganic ORMOCORE b59, acrylate-based AKRE23, novel organic-inorganic Zr containing hybrid SZ2080, and biodegradable PEG-DA-258. Adult myogenic stem cells were grown on these surfaces in vitro. Their adhesion, growth, and viability test results suggest good potential applicability of the materials in biomedical practice. Pieces of these polymers were implanted in rat's paravertebral back tissue. Histological examination of the implants and surrounding tissue ex vivo after 3 weeks of implantation was conducted and results show the materials to be at least as biocompatible as surgical clips or sutures. The applied direct laser writing technique seems to offer good future prospects in a polymeric 3D scaffold design for artificial tissue engineering with autologous stem cells.

  20. Boronate Affinity-Molecularly Imprinted Biocompatible Probe: An Alternative for Specific Glucose Monitoring.

    PubMed

    Chen, Guosheng; Qiu, Junlang; Fang, Xu'an; Xu, Jianqiao; Cai, Siying; Chen, Qing; Liu, Yan; Zhu, Fang; Ouyang, Gangfeng

    2016-08-19

    A biocompatible probe for specific glucose recognition is based on photoinitiated boronate affinity-molecular imprinted polymers (BA-MIPs). The unique pre-self-assembly between glucose and boronic acids creates glucose-specific memory cavities in the BA-MIPs coating. As a result, the binding constant toward glucose was enhanced by three orders of magnitude. The BA-MIPs probe was applied to glucose determination in serum and urine and implanted into plant tissues for low-destructive and long-term in vivo continuous glucose monitoring. PMID:27411946

  1. Overview of Stabilizing Ligands for Biocompatible Quantum Dot Nanocrystals

    PubMed Central

    Zhang, Yanjie; Clapp, Aaron

    2011-01-01

    Luminescent colloidal quantum dots (QDs) possess numerous advantages as fluorophores in biological applications. However, a principal challenge is how to retain the desirable optical properties of quantum dots in aqueous media while maintaining biocompatibility. Because QD photophysical properties are directly related to surface states, it is critical to control the surface chemistry that renders QDs biocompatible while maintaining electronic passivation. For more than a decade, investigators have used diverse strategies for altering the QD surface. This review summarizes the most successful approaches for preparing biocompatible QDs using various chemical ligands. PMID:22247651

  2. Biocompatibility of a Coacervate-Based Controlled Release System for Protein Delivery to the Injured Spinal Cord

    PubMed Central

    Rauck, Britta M.; Novosat, Tabitha L.; Oudega, Martin; Wang, Yadong

    2014-01-01

    The efficacy of protein-based therapies for treating injured nervous tissue is limited by the short half-life of free proteins in the body. Affinity-based biomaterial delivery systems provide sustained release of proteins, thereby extending the efficacy of such therapies. Here, we investigated the biocompatibility of a novel coacervate delivery system based on poly(ethylene argininylaspartate diglyceride) (PEAD) and heparin in the damaged spinal cord. We found that the presence of the [PEAD:heparin] coacervate did not affect the macrophage response, glial scarring, or nervous tissue loss, which are hallmarks of spinal cord injury. Moreover, the density of axons, including serotonergic axons, at the injury site and the recovery of motor and sensorimotor function were comparable in rats with and without the coacervate. These results revealed the biocompatibility of our delivery system and supported its potential to deliver therapeutic proteins to the injured nervous system. PMID:25266504

  3. Nanoscale contact mechanics of biocompatible polyzwitterionic brushes.

    PubMed

    Zhang, Zhenyu; Morse, Andrew J; Armes, Steven P; Lewis, Andrew L; Geoghegan, Mark; Leggett, Graham J

    2013-08-27

    Friction force microscopy has been used to demonstrate that biocompatible, lubricious poly(2-(methacryloyloxy)ethylphosphorylcholine) (PMPC) brushes exhibit different frictional properties depending on the medium (methanol, ethanol, 2-propanol, and water; the latter also with different quantities of added salt). The chemical functionalization of the probe (amine-, carboxylic acid-, and methyl-terminated probes were used) is not as important as the medium in determining the contact mechanics. For solvents such as methanol, where the adhesion between AFM probe and PMPC brushes is negligible, a linear friction-load relationship is observed. In contrast, the friction-load plot is nonlinear in ethanol or water, media in which stronger adhesion is measured. For ethanol, the data indicate Johnson-Kendall-Roberts (JKR) mechanics, whereas the Derjaguin-Muller-Toporov (DMT) model provided a good fit for the data acquired in water. Contact mechanics on zwitterionic PMPC brushes immersed in aqueous solutions of varying ionic strength followed the same trend, with high adhesion energies being correlated with a nonlinear friction-load relationship. These results can be rationalized by treating the friction force as the sum of a load-dependent term, attributed to molecular plowing, and an area-dependent shear term. In a good solvent for PMPC such as methanol, the shear term is negligible and the sliding interaction is dominated by molecular plowing. However, the adhesion energy is significantly larger in water and ethanol and the shear term is no longer negligible. PMID:23855771

  4. Evaluation of iron oxide nanoparticle biocompatibility

    PubMed Central

    Hanini, Amel; Schmitt, Alain; Kacem, Kamel; Chau, François; Ammar, Souad; Gavard, Julie

    2011-01-01

    Nanotechnology is an exciting field of investigation for the development of new treatments for many human diseases. However, it is necessary to assess the biocompatibility of nanoparticles in vitro and in vivo before considering clinical applications. Our characterization of polyol-produced maghemite γ-Fe2O3 nanoparticles showed high structural quality. The particles showed a homogeneous spherical size around 10 nm and could form aggregates depending on the dispersion conditions. Such nanoparticles were efficiently taken up in vitro by human endothelial cells, which represent the first biological barrier to nanoparticles in vivo. However, γ-Fe2O3 can cause cell death within 24 hours of exposure, most likely through oxidative stress. Further in vivo exploration suggests that although γ-Fe2O3 nanoparticles are rapidly cleared through the urine, they can lead to toxicity in the liver, kidneys and lungs, while the brain and heart remain unaffected. In conclusion, γ-Fe2O3 could exhibit harmful properties and therefore surface coating, cellular targeting, and local exposure should be considered before developing clinical applications. PMID:21589646

  5. Evaluation of iron oxide nanoparticle biocompatibility.

    PubMed

    Hanini, Amel; Schmitt, Alain; Kacem, Kamel; Chau, François; Ammar, Souad; Gavard, Julie

    2011-01-01

    Nanotechnology is an exciting field of investigation for the development of new treatments for many human diseases. However, it is necessary to assess the biocompatibility of nanoparticles in vitro and in vivo before considering clinical applications. Our characterization of polyol-produced maghemite γ-Fe(2)O(3) nanoparticles showed high structural quality. The particles showed a homogeneous spherical size around 10 nm and could form aggregates depending on the dispersion conditions. Such nanoparticles were efficiently taken up in vitro by human endothelial cells, which represent the first biological barrier to nanoparticles in vivo. However, γ-Fe(2)O(3) can cause cell death within 24 hours of exposure, most likely through oxidative stress. Further in vivo exploration suggests that although γ-Fe(2)O(3) nanoparticles are rapidly cleared through the urine, they can lead to toxicity in the liver, kidneys and lungs, while the brain and heart remain unaffected. In conclusion, γ-Fe(2)O(3) could exhibit harmful properties and therefore surface coating, cellular targeting, and local exposure should be considered before developing clinical applications. PMID:21589646

  6. Ocular Biocompatibility of Nitinol Intraocular Clips

    PubMed Central

    Velez-Montoya, Raul; Erlanger, Michael

    2012-01-01

    Purpose. To evaluate the tolerance and biocompatibility of a preformed nitinol intraocular clip in an animal model after anterior segment surgery. Methods. Yucatan mini-pigs were used. A 30-gauge prototype injector was used to attach a shape memory nitinol clip to the iris of five pigs. Another five eyes received conventional polypropylene suture with a modified Seipser slip knot. The authors compared the surgical time of each technique. All eyes underwent standard full-field electroretinogram at baseline and 8 weeks after surgery. The animals were euthanized and eyes collected for histologic analysis after 70 days (10 weeks) postsurgery. The corneal thickness, corneal endothelial cell counts, specular microscopy parameters, retina cell counts, and electroretinogram parameters were compared between the groups. A two sample t-test for means and a P value of 0.05 were use for assessing statistical differences between measurements. Results. The injection of the nitinol clip was 15 times faster than conventional suturing. There were no statistical differences between the groups for corneal thickness, endothelial cell counts, specular microscopy parameters, retina cell counts, and electroretinogram measurements. Conclusions. The nitinol clip prototype is well tolerated and showed no evidence of toxicity in the short-term. The injectable delivery system was faster and technically less challenging than conventional suture techniques. PMID:22064995

  7. Biocompatibility and hemocompatibility of polyvinyl alcohol hydrogel used for vascular grafting--In vitro and in vivo studies.

    PubMed

    Alexandre, Nuno; Ribeiro, Jorge; Gärtner, Andrea; Pereira, Tiago; Amorim, Irina; Fragoso, João; Lopes, Ascensão; Fernandes, João; Costa, Elísio; Santos-Silva, Alice; Rodrigues, Miguel; Santos, José Domingos; Maurício, Ana Colette; Luís, Ana Lúcia

    2014-12-01

    Polyvinyl alcohol hydrogel (PVA) is a synthetic polymer with an increasing application in the biomedical field that can potentially be used for vascular grafting. However, the tissue and blood-material interactions of such gels and membranes are unknown in detail. The objectives of this study were to: (a) assess the biocompatibility and (b) hemocompatibility of PVA-based membranes in order to get some insight into its potential use as a vascular graft. PVA was evaluated isolated or in copolymerization with dextran (DX), a biopolymer with known effects in blood coagulation homeostasis. The effects of the mesenchymal stem cells (MSCs) isolated from the umbilical cord Wharton's jelly in the improvement of PVA biocompatibility and in the vascular regeneration were also assessed. The biocompatibility of PVA was evaluated by the implantation of membranes in subcutaneous tissue using an animal model (sheep). Histological samples were assessed and the biological response parameters such as polymorphonuclear neutrophilic leucocytes and macrophage scoring evaluated in the implant/tissue interface by International Standards Office (ISO) Standard 10993-6 (annex E). According to the scoring system based on those parameters, a total value was obtained for each animal and for each experimental group. The in vitro hemocompatibility studies included the classic hemolysis assay and both human and sheep bloods were used. Relatively to biocompatibility results, PVA was slightly irritant to the surrounding tissues; PVA-DX or PVA plus MSCs groups presented the lowest score according to ISO Standard 10993-6. Also, PVA was considered a nonhemolytic biomaterial, presenting the lowest values for hemolysis when associated to DX. PMID:24488670

  8. Biocompatibility and setting time of CPM-MTA and white Portland cement clinker with or without calcium sulfate

    PubMed Central

    BRAMANTE, Clovis Monteiro; KATO, Marcia Magro; de ASSIS, Gerson Francisco; DUARTE, Marco Antonio Hungaro; BERNARDINELI, Norberti; de MORAES, Ivaldo Gomes; GARCIA, Roberto Brandão; ORDINOLA-ZAPATA, Ronald; BRAMANTE, Alexandre Silva

    2013-01-01

    Objective: To evaluate the biocompatibility and the setting time of Portland cement clinker with or without 2% or 5% calcium sulfate and MTA-CPM. Material and Methods: Twenty-four mice (Rattus norvegicus) received subcutaneously polyethylene tubes filled with Portland cement clinker with or without 2% or 5% calcium sulfate and MTA. After 15, 30 and 60 days of implantation, the animals were killed and specimens were prepared for microscopic analysis. For evaluation of the setting time, each material was analyzed using Gilmore needles weighing 113.5 g and 456.5 g, according to the ASTM specification Number C266-08 guideline. Data were analyzed by ANOVA and Tukey's test for setting time and Kruskal-Wallis and Dunn test for biocompatibility at 5% significance level. Results: Histologic observation showed no statistically significant difference of biocompatibility (p>0.05) among the materials in the subcutaneous tissues. For the setting time, clinker without calcium sulfate showed the shortest initial and final setting times (6.18 s/21.48 s), followed by clinker with 2% calcium sulfate (9.22 s/25.33 s), clinker with 5% calcium sulfate (10.06 s/42.46 s) and MTA (15.01 s/42.46 s). Conclusions: All the tested materials showed biocompatibility and the calcium sulfate absence shortened the initial and final setting times of the white Portland cement clinker. PMID:23559109

  9. A novel method to in vitro evaluate biocompatibility of nanoscaled scaffolds.

    PubMed

    Li, Xiaoming; Wang, Zheng; Zhao, Tianxiao; Yu, Bo; Fan, Yubo; Feng, Qingling; Cui, Fu-Zhai; Watari, Fumio

    2016-09-01

    This study provided a new method to in vitro evaluate the biocompatibility of nanoscaled scaffolds for tissue engineering with neutrophils other than ordinary cell culture. The neutrophils were separated from human peripheral blood of healthy subjects. In vitro degradation product of nanohydroxyapatite/collagen (nHAC), nanohydroxyapatite/collagen/poly (L-lactic acid) (nHACP), and nHACP reinforced by chitin fibers (nHACP/CF) in the D-Hank's Balanced Salt Solution (D-HBSS) was used as the testing solution, which was thereafter mixed with the neutrophils. It was shown that the cell survival rate in the testing solutions had no significant difference from that in the D-HBSS (control). However, from both gene and protein expression levels, the lactate dehydrogenase and tumor necrosis factor-alpha of the neutrophils in the nHACP/CF testing solution were found lowest during the whole testing period; the main reasons of which might be that the calcium release rate of the scaffold was slowest and that the pH value of its degradation solution was nearest to that of human body. Moreover, in vivo experiments showed that most inflammation reactions happened for nHAC and poly (L-lactic acid) groups, while the least inflammation reactions happened for nHACP/CF group in the subcutaneous dorsum of mice at 2 weeks after the surgery, which confirmed the in vitro findings. These results indicated that the pH value and the certain metal iron concentration of the nanoscaled scaffold degradation solution should be two important factors that significantly affect its biocompatibility. This study provides a simple and effective biocompatibility test method for biodegradable nanoscaled tissue engineering scaffolds. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2117-2125, 2016. PMID:27087116

  10. Size-engineered biocompatible polymeric nanophotosensitizer for locoregional photodynamic therapy of cancer.

    PubMed

    Jeong, Keunsoo; Park, Solji; Lee, Yong-Deok; Kang, Chi Soo; Kim, Hyun Jun; Park, Hyeonjong; Kwon, Ick Chan; Kim, Jungahn; Park, Chong Rae; Kim, Sehoon

    2016-08-01

    Current approaches in use of water-insoluble photosensitizers for photodynamic therapy (PDT) of cancer often demand a nano-delivery system. Here, we report a photosensitizer-loaded biocompatible nano-delivery formulation (PPaN-20) whose size was engineered to ca. 20nm to offer improved cell/tissue penetration and efficient generation of cytotoxic singlet oxygen. PPaN-20 was fabricated through the physical assembly of all biocompatible constituents: pyropheophorbide-a (PPa, water-insoluble photosensitizer), polycaprolactone (PCL, hydrophobic/biodegradable polymer), and Pluronic F-68 (clinically approved polymeric surfactant). Repeated microemulsification/evaporation method resulted in a fine colloidal dispersion of PPaN-20 in water, where the particulate PCL matrix containing well-dispersed PPa molecules inside was stabilized by the Pluronic corona. Compared to a control sample of large-sized nanoparticles (PPaN-200) prepared by a conventional solvent displacement method, PPaN-20 revealed optimal singlet oxygen generation and efficient cellular uptake by virtue of the suitably engineered size and constitution, leading to high in vitro phototoxicity against cancer cells. Upon administration to tumor-bearing mice by peritumoral route, PPaN-20 showed efficient tumor accumulation by the enhanced cell/tissue penetration evidenced by in vivo near-infrared fluorescence imaging. The in vivo PDT treatment with peritumorally administrated PPaN-20 showed significantly enhanced suppression of tumor growth compared to the control group, demonstrating great potential as a biocompatible photosensitizing agent for locoregional PDT treatment of cancer. PMID:27107384

  11. Biocompatibility and biomineralization assessment of bioceramic-, epoxy-, and calcium hydroxide-based sealers.

    PubMed

    Bueno, Carlos Roberto Emerenciano; Valentim, Diego; Marques, Vanessa Abreu Sanches; Gomes-Filho, João Eduardo; Cintra, Luciano Tavares Angelo; Jacinto, Rogério Castilho; Dezan-Junior, Eloi

    2016-06-14

    Obturation of the root canal system aims to fill empty spaces, promoting hermetic sealing and preventing bacterial activity in periapical tissues. This should provide optimal conditions for repair, stimulating the process of biomineralization. An endodontic sealer should be biocompatible once it is in direct contact with periapical tissues. The aim of this study was to evaluate the rat subcutaneous tissue response to implanted polyethylene tubes filled with Smartpaste Bio, Acroseal, and Sealapex and investigate mineralization ability of these endodontic sealers. Forty Wistar rats were assigned to the three sealers groups and control group, (n = 10 animals/group) and received subcutaneous implants containing the test sealers, and the control group were implanted with empty tubes. After days 7, 15, 30, and 60, animals were euthanized and polyethylene tubes were removed with the surrounding tissues. Inflammatory infiltrate and thickness of the fibrous capsule were histologically evaluated. Mineralization was analyzed by Von Kossa staining and polarized light. Data were tabulated and analyzed via Kruskal-Wallis and Dunn's test. All tested materials induced a moderate inflammatory reaction in the initial periods. Smartpaste Bio induced the mildest inflammatory reactions after day 15. No difference was observed among groups after days 30 or 60. Von Kossa-positive staining and birefringent structures observed under polarized light revealed a larger mineralization area in Sealapex-treated animals followed by Smartpaste Bio-treated animals. At the end of the experiment, all tested sealers were found to be biocompatible. All sealers induced biomineralization, except Acroseal, which induced a mild tissue reaction. PMID:27305513

  12. Synthesis, Biodegradability, and Biocompatibility of Lysine Diisocyanate–Glucose Polymers

    PubMed Central

    ZHANG, JIAN-YING; BECKMAN, ERIC J.; HU, JING; YANG, GUO-GUANG; AGARWAL, SUDHA; HOLLINGER, JEFFREY O.

    2016-01-01

    The success of a tissue-engineering application depends on the use of suitable biomaterials that degrade in a timely manner and induce the least immunogenicity in the host. With this purpose in mind, we have attempted to synthesize a novel nontoxic biodegradable lysine diisocyanate (LDI)-and glucose-based polymer via polymerization of highly purified LDI with glucose and its subsequent hydration to form a spongy matrix. The LDI–glucose polymer was degradable in aqueous solutions at 37, 22, and 4°C, and yielded lysine and glucose as breakdown products. The degradation products of the LDI–glucose polymer did not significantly affect the pH of the solution. The physical properties of the polymer were found to be adequate for supporting cell growth in vitro, as evidenced by the fact that rabbit bone marrow stromal cells (BMSCs) attached to the polymer matrix, remained viable on its surface, and formed multilayered confluent cultures with retention of their phenotype over a period of 2 to 4 weeks. These observations suggest that the LDI–glucose polymer and its degradation products were nontoxic in vitro. Further examination in vivo over 8 weeks revealed that subcutaneous implantation of hydrated matrix degraded in vivo three times faster than in vitro. The implanted polymer was not immunogenic and did not induce antibody responses in the host. Histological analysis of the implanted polymer showed that LDI–glucose polymer induced a minimal foreign body reaction, with formation of a capsule around the degrading polymer. The results suggest that biodegradable peptide-based polymers can be synthesized, and may potentially find their way into biomedical applications because of their biodegradability and biocompatibility. PMID:12459056

  13. In vitro biocompatibility and bioactivity of microencapsulated heparan sulfate.

    PubMed

    Luong-Van, Emma; Grøndahl, Lisbeth; Nurcombe, Victor; Cool, Simon

    2007-04-01

    The glycosaminoglycan sugar heparan sulfate (HS) is an attractive agent for the repair of bone defects due to its ability to regulate endogenous growth factors. The sustained delivery of HS to the localized wound site over the period of healing which can last for over 1 month may prove advantageous for its therapeutic use. In this study we investigated the encapsulation of HS by the water-in oil-in water (W(1)/O/W(2)) technique in polycaprolactone (PCL) microcapsules as a prolonged delivery device. Encapsulation efficiencies of 70% could be achieved by using a 1:1 mixture of dichloromethane (DCM) and acetone as the solvent in the organic phase, while DCM alone gave poor encapsulation. Although addition of polyvinyl alcohol (PVA) to the drug phase did not affect the size or drug loading of the microcapsules, it did however produce a large change in the morphology and drug distribution, which resulted in different release rates. Release from capsules made with PVA in the drug phase reached 60% after 40 days, while those made with water in the drug phase completed release after 20 days. In vitro biocompatibility studies were performed and detected no increase in cell death in human mesenchymal stem cells (hMSC) or induction of an inflammatory response in macrophages after exposure to release products from HS-loaded microcapsules. The released HS retained its ability to increase the proliferation of hMSC after the encapsulation process. These results indicate that encapsulation of HS by the W(1)/O/W(2) method creates a promising device for the repair of bone tissue. PMID:17257666

  14. Pegylation increases platelet biocompatibility of gold nanoparticles.

    PubMed

    Santos-Martinez, Maria Jose; Rahme, Kamil; Corbalan, J Jose; Faulkner, Colm; Holmes, Justin D; Tajber, Lidia; Medina, Carlos; Radomski, Marek Witold

    2014-06-01

    The increasing use of gold nanoparticles in medical diagnosis and treatment has raised the concern over their blood compatibility. The interactions of nanoparticles with blood components may lead to platelet aggregation and endothelial dysfunction. Therefore, medical applications of gold nanoparticles call for increased nanoparticle stability and biocompatibility. Functionalisation of nanoparticles with polythelene glycol (PEGylation) is known to modulate cell-particle interactions. Therefore, the aim of the current study was to investigate the effects of PEGylated-gold nanoparticles on human platelet function and endothelial cells in vitro. Gold nanoparticles, 15 nm in diameter, were synthesised in water using sodium citrate as a reducing and stabilising agent. Functionalised polyethylene glycol-based thiol polymers were used to coat and stabilise pre-synthesised gold nanoparticles. The interaction of gold nanoparticles-citrate and PEGylated-gold nanoparticles with human platelets was measured by Quartz Crystal Microbalance with Dissipation. Platelet-nanoparticles interaction was imaged using phase-contrast, scanning and transmission electron microscopy. The inflammatory effects of gold nanoparticles-citrate and PEGylated-gold nanoparticles in endothelial cells were measured by quantitative real time polymerase chain reaction. PEGylated-gold nanoparticles were stable under physiological conditions and PEGylated-gold nanoparticles-5400 and PEGylated-gold nanoparticles-10800 did not affect platelet aggregation as measured by Quartz Crystal Microbalance with Dissipation. In addition, PEGylated-gold nanoparticles did not induce an inflammatory response when incubated with endothelial cells. Therefore, this study shows that PEGylated-gold nanoparticles with a higher molecular weight of the polymer chain are both platelet- and endothelium-compatible making them attractive candidates for biomedical applications. PMID:24749395

  15. Enhancement of biocompatibility of nickel-titanium by laser surface modification technology

    NASA Astrophysics Data System (ADS)

    Ng, Ka Wai

    Nickel Titanium is a relatively new biomaterial that has attracted research interest for biomedical application. The good biocompatibility with specific functional properties of shape memory effect and superelasticity creates a smart material for medical applications. However, there are still concerns on nickel ion release of this alloy if it is going to be implanted for a long time. Nickel ion is carcinogenic and also causes allergic response and degeneration of muscle tissue. The subsequent release of Ni+ ions into the body system is fatal for the long term application of this alloy in the human body. To improve the long term biocompatibility and corrosion properties of NiTi, different surface treatment techniques have been investigated but no optimum technique has been established yet. This project will investigate the feasibility of applying laser surface alloying technique to improve the corrosion resistance and biocompatibility of NiTi in simulated body fluid condition. This thesis summarizes the result of laser surface modification of NiTi with Mo, Nb and Co using CO2 laser. The modified layer, which is free of microcracks and pores, acts as physical barrier to reduce nickel release and enhance the surface properties. The hardness values of the Mo-alloyed NiTi, Nb-alloyed NiTi and Co-alloyed NiTi surface were found to be three to four times harder than the NiTi substrate. Corrosion polarization tests also showed that the alloyed NiTi are significantly more resistant than the NiTi alloy. The release of Ni ions can be greatly reduced after laser surface alloying NiTi with Mo, Nb and Co. The improvement in wettability characteristics, the growth of the apatite on the specimen's surface and the adhesion of cell confirm the good biocompatibility after laser surface alloying. It is concluded that laser surface alloying is one of the potential technique not only to improve the corrosion resistance with low nickel release rate, but also retain the good

  16. Sterilization, toxicity, biocompatibility and clinical applications of polylactic acid/polyglycolic acid copolymers.

    PubMed

    Athanasiou, K A; Niederauer, G G; Agrawal, C M

    1996-01-01

    This is a review of salient studies of sterilization, toxicity, biocompatibility, clinical applications and current work in the field of orthopaedics, using implants made of polylactic acid (PLA), polyglycolic acid (PGA) and their copolymers. The intrinsic nature of these biomaterials renders them suitable for applications where temporally slow releases of bioactive agents in situ may be required. They are also desirable as fixation devices of bone, because they can virtually eliminate osteopenia associated with stress shielding or additional surgery. The majority of currently available sterilization techniques are not suitable for these thermoplastic materials and it may be desirable to develop new sterilization standards, which can account for the special character of PLA-PGA materials. Biocompatibility and toxicity studies suggest that, overall, PLA-PGA biomaterials may be suitable for orthopaedic applications, although certain problems, especially pertaining to reduction in cell proliferation, have been reported. Clinical applications are also promising, albeit not without problems usually associated with transient tissue inflammation. The future of these materials appears bright, especially in soft tissues. They may be used to address the exceedingly complex problem of osteochondral repair, but also as a means to enhance fixation and repair processes in tendons and ligaments. PMID:8624401

  17. Biocompatibility of corrosion-resistant zeolite coatings for titanium alloy biomedical implants.

    PubMed

    Bedi, Rajwant S; Beving, Derek E; Zanello, Laura P; Yan, Yushan

    2009-10-01

    Titanium alloy, Ti6Al4V, is widely used in dental and orthopedic implants. Despite its excellent biocompatibility, Ti6Al4V releases toxic Al and V ions into the surrounding tissue after implantation. In addition, the elastic modulus of Ti6Al4V ( approximately 110GPa) is significantly higher than that of bone (10-40GPa), leading to a modulus mismatch and consequently implant loosening and deosteointegration. Zeolite coatings are proposed to prevent the release of the toxic ions into human tissue and enhance osteointegration by matching the mechanical properties of bone. Zeolite MFI coatings are successfully synthesized on commercially pure titanium and Ti6Al4V for the first time. The coating shows excellent adhesion by incorporating titanium from the substrate within the zeolite framework. Higher corrosion resistance than the bare titanium alloy is observed in 0.856M NaCl solution at pHs of 7.0 and 1.0. Zeolite coatings eliminate the release of cytotoxic Al and V ions over a 7 day period. Pluripotent mouse embryonic stem cells show higher adhesion and cell proliferation on the three-dimensional zeolite microstructure surface compared with a two-dimensional glass surface, indicating that the zeolite coatings are highly biocompatible. PMID:19433139

  18. Nanospearing - Biomolecule Delivery and Its Biocompatibility

    NASA Astrophysics Data System (ADS)

    Cai, Dong; Kempa, Krzysztof; Ren, Zhifeng; Carnahan, David; Chiles, Thomas C.

    stimulation in as robust a manner as cells left untreated. Our study suggests the biocompatibility of the nanospearing procedure and PECVD nanotubes under the proposed spearing conditions with regard to the humoral component of the immune system, therefore, reducing concerns that surround in vivo applications of CNTs.

  19. Biocompatible multilayer capsules engineered with a graphene oxide derivative: synthesis, characterization and cellular uptake

    NASA Astrophysics Data System (ADS)

    Del Mercato, Loretta L.; Guerra, Flora; Lazzari, Gianpiero; Nobile, Concetta; Bucci, Cecilia; Rinaldi, Rosaria

    2016-03-01

    Graphene-based capsules have strong potential for a number of applications, including drug/gene delivery, tissue engineering, sensors, catalysis and reactors. The ability to integrate graphene into carrier systems with three-dimensional (3D) geometry may open new perspectives both for fundamental tests of graphene mechanics and for novel (bio)technological applications. However, the assembly of 3D complexes from graphene or its derivatives is challenging because of its poor stability under biological conditions. In this work, we attempted to integrate a layer of graphene oxide derivative into the shell of biodegradable capsules by exploiting a facile layer-by-layer (LbL) protocol. As a first step we optimized the LbL protocol to obtain colloidal suspensions of isolated capsules embedding the graphene oxide derivative. As a following step, we investigated in detail the morphological properties of the hybrid capsules, and how the graphene oxide derivative layer influences the porosity and the robustness of the multilayer composite shells. Finally, we verified the uptake of the capsules modified with the GO derivative by two cell lines and studied their intracellular localization and biocompatibility. As compared to pristine capsules, the graphene-modified capsules possess reduced porosity, reduced shell thickness and a higher stability against osmotic pressure. They show remarkable biocompatibility towards the tested cells and long-term colloidal stability and dispersion. By combining the excellent mechanical properties of a graphene oxide derivative with the high versatility of the LbL method, robust and flexible biocompatible polymeric capsules with novel characteristics have been fabricated.Graphene-based capsules have strong potential for a number of applications, including drug/gene delivery, tissue engineering, sensors, catalysis and reactors. The ability to integrate graphene into carrier systems with three-dimensional (3D) geometry may open new perspectives

  20. Amplifying the Red-Emission of Upconverting Nanoparticles for Biocompatible Clinically Used Prodrug-Induced Photodynamic Therapy

    DOE PAGESBeta

    Punjabi, Amol; Wu, Xiang; Tokatli-Apollon, Amira; El-Rifai, Mahmoud; Lee, Hyungseok; Zhang, Yuanwei; Wang, Chao; Liu, Zhuang; Chan, Emory M.; Duan, Chunying; et al

    2014-09-25

    A class of biocompatible upconverting nanoparticles (UCNPs) with largely amplified red-emissions was developed. The optimal UCNP shows a high absolute upconversion quantum yield of 3.2% in red-emission, which is 15-fold stronger than the known optimal β-phase core/shell UCNPs. When conjugated to aminolevulinic acid, a clinically used photodynamic therapy (PDT) prodrug, significant PDT effect in tumor was demonstrated in a deep-tissue (>1.2 cm) setting in vivo at a biocompatible laser power density. Furthermore, we show that our UCNP–PDT system with NIR irradiation outperforms clinically used red light irradiation in a deep tumor setting in vivo. This study marks a major stepmore » forward in photodynamic therapy utilizing UCNPs to effectively access deep-set tumors.Lastly, it also provides an opportunity for the wide application of upconverting red radiation in photonics and biophotonics.« less

  1. Amplifying the Red-Emission of Upconverting Nanoparticles for Biocompatible Clinically Used Prodrug-Induced Photodynamic Therapy

    SciTech Connect

    Punjabi, Amol; Wu, Xiang; Tokatli-Apollon, Amira; El-Rifai, Mahmoud; Lee, Hyungseok; Zhang, Yuanwei; Wang, Chao; Liu, Zhuang; Chan, Emory M.; Duan, Chunying; Han, Gang

    2014-09-25

    A class of biocompatible upconverting nanoparticles (UCNPs) with largely amplified red-emissions was developed. The optimal UCNP shows a high absolute upconversion quantum yield of 3.2% in red-emission, which is 15-fold stronger than the known optimal β-phase core/shell UCNPs. When conjugated to aminolevulinic acid, a clinically used photodynamic therapy (PDT) prodrug, significant PDT effect in tumor was demonstrated in a deep-tissue (>1.2 cm) setting in vivo at a biocompatible laser power density. Furthermore, we show that our UCNP–PDT system with NIR irradiation outperforms clinically used red light irradiation in a deep tumor setting in vivo. This study marks a major step forward in photodynamic therapy utilizing UCNPs to effectively access deep-set tumors.Lastly, it also provides an opportunity for the wide application of upconverting red radiation in photonics and biophotonics.

  2. Amplifying the Red-Emission of Upconverting Nanoparticles for Biocompatible Clinically Used Prodrug-Induced Photodynamic Therapy

    PubMed Central

    2015-01-01

    A class of biocompatible upconverting nanoparticles (UCNPs) with largely amplified red-emissions was developed. The optimal UCNP shows a high absolute upconversion quantum yield of 3.2% in red-emission, which is 15-fold stronger than the known optimal β-phase core/shell UCNPs. When conjugated to aminolevulinic acid, a clinically used photodynamic therapy (PDT) prodrug, significant PDT effect in tumor was demonstrated in a deep-tissue (>1.2 cm) setting in vivo at a biocompatible laser power density. Furthermore, we show that our UCNP–PDT system with NIR irradiation outperforms clinically used red light irradiation in a deep tumor setting in vivo. This study marks a major step forward in photodynamic therapy utilizing UCNPs to effectively access deep-set tumors. It also provides an opportunity for the wide application of upconverting red radiation in photonics and biophotonics. PMID:25291544

  3. Biocompatibility correlation of polymeric materials using human osteosarcoma cells

    NASA Astrophysics Data System (ADS)

    Geckeler, K. E.; Wacker, Roland; Aicher, Wilhelm K.

    Metal implants are the preferred materials to generate articular prostheses, plates, or bone pegs in orthopedic surgery. Although titanium and titanium alloys show a relatively good biocompatibility, clinical experience revealed that coating of the metallic implant surface may increase the biocompatibility. In a search for optimum bone implant surfaces, we determined polarity and contact angle parameters of a variety of polymers and substances and correlated the findings in a biocompatibility assay using an in vitro bone cell model. We report that an optimum adherence of SAOS-2 cells to such surfaces and a good vitality for polymers are characterized by water-based contact angles of 80° and 20° for advancing and receding probes, respectively.

  4. Preparation of a biocompatible magnetic film from an aqueous ferrofluid

    NASA Astrophysics Data System (ADS)

    Albornoz, Cecilia; Jacobo, Silvia E.

    2006-10-01

    Very promising nanoparticles for biomedical applications or in medical drug targeting are superparamagnetic nanoparticles based on a core consisting of iron oxides (SPION) that can be targeted through external magnets. Polyvinyl alcohol (PVA) is a unique synthetic biocompatible polymer that can be chemically cross-linked to form a gel. Biotechnology applications of magnetic gels include biosensors, targeted drug delivery, artificial muscles and magnetic buckles. These gels are produced by incorporating magnetic materials in the polymer composites. In this paper we report the synthesis of an aqueous ferrofluid and the preparation of a biocompatible magnetic gel with polyvinyl alcohol and glutharaldehyde (GTA). HClO 4 was used to induce the peptization since this kind of ferrofluid does not have surfactant. The magnetic gel was dried to generate a biocompatible film.

  5. Rapid isothermal substrate microfabrication of a biocompatible thermoplastic elastomer for cellular contact guidance.

    PubMed

    Guillemette, Maxime D; Roy, Emmanuel; Auger, François A; Veres, Teodor

    2011-06-01

    The use of microstructured substrates to study and influence cell orientation, which plays an important role in tissue functionality, has been of great interest lately. Silicon and poly(dimethylsiloxane) substrates have typically been used, but long processing times and exogenous protein surface coating, required to enhance cell viability, limit their use as large-scale platforms. There is thus a need for a non-biodegradable biocompatible substrate that allows rapid and low cost microfabrication. In this paper a styrene-(ethylene/butylene)-styrene block co-polymer (SEBS) microstructured by a rapid replication technique using low pressure an isothermal hot embossing approach has been demonstrated. SEBS substrates were treated with oxygen plasma to enhance cell adhesion and sterilized using ethylene oxide gas. While cell adhesion to and proliferation on these substrates was as good as on tissue culture polystyrene, cellular alignment on microstructured SEBS was also very high (97.7±0.5%) when calculated within a 10° angle variation from the longitudinal axis. Furthermore, tissue sheets on microstructured SEBS have been produced and exhibited cellular alignment within the engineered tissue. In addition, these results were obtained without coating the material with exogenous proteins. Such substrates should be helpful in the culture of tissue engineered substitutes with an intrinsic orientation and to elucidate questions in cell biology. PMID:21329768

  6. Evaluation of biocompatibility and toxicity of biodegradable poly (DL-lactic acid) films.

    PubMed

    Li, Rui-Yun; Liu, Zhi-Gang; Liu, Huan-Qiu; Chen, Lei; Liu, Jian-Feng; Pan, Yue-Hai

    2015-01-01

    Regeneration and functional recovery of nerves after peripheral nerve injury is the key to peripheral nerve repair. One of the putative therapeutic strategies is to use anti-adhesion polymer films, made of polymeric biomaterials. Recently, a novel biodegradable poly (DL-lactic acid) (PDLLA) film has been prepared using a method of phase transformation with biodegradable polylactic acid polymer as the substrate. This novel, anti-adhesion film has a porous structure, which provides better mechanical properties, better flexibility, more complete diffusion through the polymer of tissue biologic factors like growth factors, and more controllable degradation compared to traditional non-porous films. Little is known, however, about the in vitro and in vivo biocompatibility and cytotoxicity of this type of PDLLA film. Therefore, our aim was to evaluate the biocompatibility and cytotoxicity of this novel PDLLA film using various experimental methods, including a skin irritation test, MTT analysis, and the mouse bone marrow cell micronucleus test, as well as hematology or clinical chemistry measurements in rats after receiving sciatic nerve transection and anastomosis with wrapping of the anastomosis with DLLA films. We demonstrated that exposure to PDLLA film extracts did not generate apparent erythema or edema in rabbit skin and had no effect on the proliferation of Vero cells. Additionally, treatment with PDLLA film extracts did not alter the incidence of micronucleated polychromatic erythrocytes as compared with saline Treated group. Furthermore, implantation of PDLLA film did not alter liver or renal function as measured by serum levels of ALT, AST, TP, A/G, Cr, and BUN, and pathologic examinations showed that implantation of PDLLA film did not cause pathologic changes to the rat liver, kidney, pancreas, or spleen. Taken together, these results suggest that PDLLA films have excellent biocompatibility and no obvious toxicity in vivo, and may be used to prevent nerve

  7. Evaluation of biocompatibility and toxicity of biodegradable poly (DL-lactic acid) films

    PubMed Central

    Li, Rui-Yun; Liu, Zhi-Gang; Liu, Huan-Qiu; Chen, Lei; Liu, Jian-Feng; Pan, Yue-Hai

    2015-01-01

    Regeneration and functional recovery of nerves after peripheral nerve injury is the key to peripheral nerve repair. One of the putative therapeutic strategies is to use anti-adhesion polymer films, made of polymeric biomaterials. Recently, a novel biodegradable poly (DL-lactic acid) (PDLLA) film has been prepared using a method of phase transformation with biodegradable polylactic acid polymer as the substrate. This novel, anti-adhesion film has a porous structure, which provides better mechanical properties, better flexibility, more complete diffusion through the polymer of tissue biologic factors like growth factors, and more controllable degradation compared to traditional non-porous films. Little is known, however, about the in vitro and in vivo biocompatibility and cytotoxicity of this type of PDLLA film. Therefore, our aim was to evaluate the biocompatibility and cytotoxicity of this novel PDLLA film using various experimental methods, including a skin irritation test, MTT analysis, and the mouse bone marrow cell micronucleus test, as well as hematology or clinical chemistry measurements in rats after receiving sciatic nerve transection and anastomosis with wrapping of the anastomosis with DLLA films. We demonstrated that exposure to PDLLA film extracts did not generate apparent erythema or edema in rabbit skin and had no effect on the proliferation of Vero cells. Additionally, treatment with PDLLA film extracts did not alter the incidence of micronucleated polychromatic erythrocytes as compared with saline Treated group. Furthermore, implantation of PDLLA film did not alter liver or renal function as measured by serum levels of ALT, AST, TP, A/G, Cr, and BUN, and pathologic examinations showed that implantation of PDLLA film did not cause pathologic changes to the rat liver, kidney, pancreas, or spleen. Taken together, these results suggest that PDLLA films have excellent biocompatibility and no obvious toxicity in vivo, and may be used to prevent nerve

  8. Biocompatible multilayer capsules engineered with a graphene oxide derivative: synthesis, characterization and cellular uptake.

    PubMed

    del Mercato, Loretta L; Guerra, Flora; Lazzari, Gianpiero; Nobile, Concetta; Bucci, Cecilia; Rinaldi, Rosaria

    2016-04-14

    Graphene-based capsules have strong potential for a number of applications, including drug/gene delivery, tissue engineering, sensors, catalysis and reactors. The ability to integrate graphene into carrier systems with three-dimensional (3D) geometry may open new perspectives both for fundamental tests of graphene mechanics and for novel (bio)technological applications. However, the assembly of 3D complexes from graphene or its derivatives is challenging because of its poor stability under biological conditions. In this work, we attempted to integrate a layer of graphene oxide derivative into the shell of biodegradable capsules by exploiting a facile layer-by-layer (LbL) protocol. As a first step we optimized the LbL protocol to obtain colloidal suspensions of isolated capsules embedding the graphene oxide derivative. As a following step, we investigated in detail the morphological properties of the hybrid capsules, and how the graphene oxide derivative layer influences the porosity and the robustness of the multilayer composite shells. Finally, we verified the uptake of the capsules modified with the GO derivative by two cell lines and studied their intracellular localization and biocompatibility. As compared to pristine capsules, the graphene-modified capsules possess reduced porosity, reduced shell thickness and a higher stability against osmotic pressure. They show remarkable biocompatibility towards the tested cells and long-term colloidal stability and dispersion. By combining the excellent mechanical properties of a graphene oxide derivative with the high versatility of the LbL method, robust and flexible biocompatible polymeric capsules with novel characteristics have been fabricated. PMID:26892453

  9. Biocompatibility of diamond-like nanocomposite thin films.

    PubMed

    Das, T; Ghosh, D; Bhattacharyya, T K; Maiti, T K

    2007-03-01

    Diamond-like nanocomposite (DLN) films consist of network structure of amorphous carbon and quartz like silicon. In the present work, DLN films have been synthesized on pyrex glass and subsequently, their biocompatibility have been investigated through primary and secondary cell adhesion, cytotoxicity, protein adsorption and murine peritoneal macrophage activation experiments. Variable degree of cell and protein response have been found based on variable film synthesis parameters but in overall, required biocompatibility has been established for all types of film-coating. PMID:17334700

  10. In vivo biocompatibility studies of poly( n-vinyl 2-pyrrolidone/itaconic acid) hydrogels synthesized by γ-rays

    NASA Astrophysics Data System (ADS)

    Özdemir, S.; Özdemir, E.; Tunca, R.; Hazıroǧlu, R.; Şen, M.; Kantoǧlu, Ö.; Güven, O.

    2003-08-01

    In this study, poly( n-vinyl 2-pyrrolidone/itaconic acid) hydrogels have been synthesized by γ-rays in different compositions and their biocompatibility have been investigated as in vivo and some biochemical parameters of mice serum and histology of their tissues have been examined. By these purposes, poly( n-vinyl 2-pyrrolidone/itaconic acid) (P(VP/IA)) hydrogels were implanted to hypersensitive mice (BALB/c). One and a half months after implantation, hydrogel implanted animals were sacrificed by ether anesthesia and the area hydrogel contacted with tissue was investigated by light microscope for histopathological identification of the tissue. Then the total immunoglobulin E (IgE) level was determined by ELISA. Differential white cell count was also made to better understanding of reaction between hydrogel and tissue. These poly( n-vinyl 2-pyrrolidone/itaconic acid) hydrogels can be directly used as biomedical materials.