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1

Nano/macro porous bioactive glass scaffold  

NASA Astrophysics Data System (ADS)

Bioactive glass (BG) and ceramics have been widely studied and developed as implants to replace hard tissues of the musculo-skeletal system, such as bones and teeth. Recently, instead of using bulk materials, which usually do not degrade rapidly enough and may remain in the human body for a long time, the idea of bioscaffold for tissue regeneration has generated much interest. An ideal bioscaffold is a porous material that would not only provide a three-dimensional structure for the regeneration of natural tissue, but also degrade gradually and, eventually be replaced by the natural tissue completely. Among various material choices the nano-macro dual porous BG appears as the most promising candidate for bioscaffold applications. Here macropores facilitate tissue growth while nanopores control degradation and enhance cell response. The surface area, which controls the degradation of scaffold can also be tuned by changing the nanopore size. However, fabrication of such 3D structure with desirable nano and macro pores has remained challenging. In this dissertation, sol-gel process combined with spinodal decomposition or polymer sponge replication method has been developed to fabricate the nano-macro porous BG scaffolds. Macropores up to 100microm are created by freezing polymer induced spinodal structure through sol-gel transition, while larger macropores (>200um) of predetermined size are obtained by the polymer sponge replication technique. The size of nanopores, which are inherent to the sol-gel method of glass fabrication, has been tailored using several approaches: Before gel point, small nanopores are generated using acid catalyst that leads to weakly-branched polymer-like network. On the other hand, larger nanopores are created with the base-catalyzed gel with highly-branched cluster-like structure. After the gel point, the nanostructure can be further modified by manipulating the sintering temperature and/or the ammonia concentration used in the solvent exchange process. Although both techniques lower the surface area of BG scaffolds, the temperature-dependent sintering process closes nanopores through densification, while the concentration-dependent solvent exchange process enlarges nanopores through Ostwald-ripening type coarsening. Therefore, nanopore size and surface area of BG scaffold are independently controlled using these methods. In vitro cell and in vivo animal tissue responses have been investigated to evaluate the performance of the nano-macro porous BG scaffold. The cells are found to migrate and penetrate deep into the 3D nano-macro porous structure, while exhibiting excellent adhesion to the bioscaffold surface. Importantly, the new tissue with both blood vessels and collagen fibers is formed deep inside the implanted scaffolds without obvious inflammatory reaction. Furthermore, our observations show biological benefits of the nanopores in the BG scaffold. In comparison to BG scaffold without nanopores, cells migrate and penetrate into nano-macro dual-porous BG scaffold faster and deeper mainly because of the increase of surface area. To study the effect of nanopore topography, we fabricated BG scaffolds with the same surface area but different nanopore sizes. It is found that the initial cell attachment is significantly enhanced on the BG scaffold with the same surface area but smaller nanopores size, indicating that the nanopore topography strongly influences the performance of BG scaffold. In conclusion, the present results demonstrate most clearly the usefulness of our nano-macro dual-porous BG as a novel and superior 3D bioscaffold for regenerative medicine and hard tissue engineering.

Wang, Shaojie

2

Bioactive glass/polymer composite scaffolds mimicking bone tissue.  

PubMed

The aim of this work was the preparation and characterization of scaffolds with mechanical and functional properties able to regenerate bone. Porous scaffolds made of chitosan/gelatin (POL) blends containing different amounts of a bioactive glass (CEL2), as inorganic material stimulating biomineralization, were fabricated by freeze-drying. Foams with different compositions (CEL2/POL 0/100; 40/60; 70/30 wt %/wt) were prepared. Samples were crosslinked using genipin (GP) to improve mechanical strength and thermal stability. The scaffolds were characterized in terms of their stability in water, chemical structure, morphology, bioactivity, and mechanical behavior. Moreover, MG63 osteoblast-like cells and periosteal-derived stem cells were used to assess their biocompatibility. CEL2/POL samples showed interconnected pores having an average diameter ranging from 179 ± 5 ?m for CEL2/POL 0/100 to 136 ± 5 ?m for CEL2/POL 70/30. GP-crosslinking and the increase of CEL2 amount stabilized the composites to water solution (shown by swelling tests). In addition, the SBF soaking experiment showed a good bioactivity of the scaffold with 30 and 70 wt % CEL2. The compressive modulus increased by increasing CEL2 amount up to 2.1 ± 0.1 MPa for CEL2/POL 70/30. Dynamical mechanical analysis has evidenced that composite scaffolds at low frequencies showed an increase of storage and loss modulus with increasing frequency; furthermore, a drop of E' and E? at 1 Hz was observed, and for higher frequencies both moduli increased again. Cells displayed a good ability to interact with the different tested scaffolds which did not modify cell metabolic activity at the analyzed points. MTT test proved only a slight difference between the two cytotypes analyzed. PMID:22615261

Gentile, Piergiorgio; Mattioli-Belmonte, Monica; Chiono, Valeria; Ferretti, Concetta; Baino, Francesco; Tonda-Turo, Chiara; Vitale-Brovarone, Chiara; Pashkuleva, Iva; Reis, Rui L; Ciardelli, Gianluca

2012-05-21

3

Bioactive glass scaffolds for bone tissue engineering: state of the art and future perspectives  

PubMed Central

The repair and regeneration of large bone defects resulting from disease or trauma remains a significant clinical challenge. Bioactive glass has appealing characteristics as a scaffold material for bone tissue engineering, but the application of glass scaffolds for the repair of load-bearing bone defects is often limited by their low mechanical strength and fracture toughness. This paper provides an overview of recent developments in the fabrication and mechanical properties of bioactive glass scaffolds. The review reveals the fact that mechanical strength is not a real limiting factor in the use of bioactive glass scaffolds for bone repair, an observation not often recognized by most researchers and clinicians. Scaffolds with compressive strengths comparable to those of trabecular and cortical bones have been produced by a variety of methods. The current limitations of bioactive glass scaffolds include their low fracture toughness (low resistance to fracture) and limited mechanical reliability, which have so far received little attention. Future research directions should include the development of strong and tough bioactive glass scaffolds, and their evaluation in unloaded and load-bearing bone defects in animal models.

Fu, Qiang; Saiz, Eduardo; Rahaman, Mohamed N.; Tomsia, Antoni P.

2011-01-01

4

Freeze casting of bioactive glass and ceramic scaffolds for bone tissue engineering  

NASA Astrophysics Data System (ADS)

The main objectives of this dissertation were to explore the production of bioactive ceramic and glass scaffolds with oriented pore architectures by unidirectional freezing of suspensions, and to characterize the mechanical and biological performance of the scaffolds. Freezing of aqueous suspensions of hydroxyapatite (HA) or bioactive 13-93 glass particles resulted in the formation of scaffolds with a lamellar-type microstructure (pore width = 5--30 microm). The addition of polar organic solvents (such as 60 wt% dioxane) to the aqueous suspensions markedly changed the morphology and size of the oriented pores, giving scaffolds with a columnar-type microstructure and larger pore width (90--110 microm). The scaffolds showed a unique 'elastic--plastic' mechanical response in compression along the orientation direction, with large strain for failure (>20%) and strain rate sensitivity. For a similar porosity, the bioactive glass scaffolds had a higher strength than the HA scaffolds, presumably because of better sintering characteristics. Columnar bioactive glass scaffolds (porosity = 55--60%) had a compressive strength of 25 +/- 3 MPa. The columnar scaffolds with the larger pore width showed better ability than the lamellar scaffolds to support the proliferation and function of murine osteoblastic cells (MLO-A5 or MC3T3-E1). Subcutaneous implantation in the dorsum of rats showed abundant tissue ingrowth into the pores of the columnar scaffolds and integration of the scaffolds with surrounding tissue. The results indicate that bioactive 13-93 glass scaffolds with the columnar microstructure could be used for the repair of segmental defects in load-bearing bones.

Fu, Qiang

5

Multifunctional magnetic mesoporous bioactive glass scaffolds with a hierarchical pore structure.  

PubMed

Hyperthermia and local drug delivery have been proposed as potential therapeutic approaches for bone defects resulting from malignant bone tumors. The development of bioactive materials with magnetic and drug delivery properties may potentially meet this target. The aim of this study was to develop a multifunctional mesoporous bioactive glass (MBG) scaffold system for both hyperthermic and local drug delivery applications. To this end iron (Fe)-containing MBG (Fe-MBG) scaffolds with a hierarchical large pores structure (300-500 ?m) and fingerprint-like mesopores (4.5 nm) have been prepared. The effects of Fe on the mesopore structure and physiochemical, magnetic, drug delivery and biological properties of MBG scaffolds have been systematically investigated. The results show that the morphology of the mesopores varied from straight channels to curved fingerprint-like channels after incorporation of Fe into MBG scaffolds. The magnetism of MBG scaffolds can be tailored by controlling the Fe content. Furthermore, the incorporation of Fe into mesoporous MBG glass scaffolds enhanced the mitochondrial activity and the expression of bone-related genes (ALP and OCN) in human bone marrow mesenchymal stem cells (BMSC) attached to the scaffolds. The Fe-MBG scaffolds obtained also possessed high specific surface areas and demonstrated sustained drug delivery. Thus Fe-MBG scaffolds are magnetic, degradable and bioactive. The multifunctionality of Fe-MBG scaffolds suggests that there is great potential for their use in the treatment and regeneration of large-bone defects caused by malignant bone tumors through a combination of hyperthermia, local drug delivery and osteoconductivity. PMID:21745610

Wu, Chengtie; Fan, Wei; Zhu, Yufang; Gelinsky, Michael; Chang, Jiang; Cuniberti, Gianaurelio; Albrecht, Victoria; Friis, Thor; Xiao, Yin

2011-06-24

6

Feasibility and tailoring of bioactive glass-ceramic scaffolds with gradient of porosity for bone grafting.  

PubMed

The aim of this research study is the preparation and characterization of graded glass-ceramic scaffolds that are able to mimic the structure of the natural bone tissue, formed by cortical and cancellous bone. The material chosen for the scaffolds preparation is a glass belonging to the system SiO( 2)-P(2)O(5)-CaO-MgO-Na( 2)O-K(2)O (CEL2). The glass was synthesized by a conventional melting-quenching route, ground, and sieved to obtain powders of specific size. The scaffolds were fabricated using different methods: polyethylene burn-off, sponge replication, a glazing-like technique, and combinations of these methods. The scaffolds were characterized through morphological observations, density measurements, volumetric shrinkage, mechanical tests, and in vitro bioactivity tests. The features of the scaffolds prepared using the different methods were compared in terms of morphological structure, pores content, and mechanical strength. The proposed scaffolds effectively mimic the cancellous/cortical bone system in terms of structure, porosity, and mechanical strength, and they exhibit a highly bioactive behavior. Therefore, these graded grafts have a great potential for biomedical applications and can be successfully proposed for the substitution of load-bearing bone portions. PMID:19451181

Vitale-Brovarone, Chiara; Baino, Francesco; Verné, Enrica

2009-05-18

7

Three-dimensional printing of hierarchical and tough mesoporous bioactive glass scaffolds with a controllable pore architecture, excellent mechanical strength and mineralization ability  

Microsoft Academic Search

New generation biomaterials for bone regeneration should be highly bioactive, resorbable and mechanically strong. Mesoporous bioactive glass (MBG), a novel bioactive material, has been used to study bone regeneration due to its excellent bioactivity, degradation and drug delivery ability, however, the construction of three-dimensional (3-D) MBG scaffolds (as for other bioactive inorganic scaffolds) for bone regeneration remains a significant challenge

Chengtie Wu; Yongxiang Luo; Gianaurelio Cuniberti; Yin Xiao; Michael Gelinsky

2011-01-01

8

Fabrication of 13-93 bioactive glass scaffolds for bone tissue engineering using indirect selective laser sintering.  

PubMed

Bioactive glasses are promising materials for bone scaffolds due to their ability to assist in tissue regeneration. When implanted in vivo, bioactive glasses can convert into hydroxyapatite, the main mineral constituent of human bone, and form a strong bond with the surrounding tissues, thus providing an advantage over polymer scaffold materials. Bone scaffold fabrication using additive manufacturing techniques can provide control over pore interconnectivity during fabrication of the scaffold, which helps in mimicking human trabecular bone. 13-93 glass, a third-generation bioactive material designed to accelerate the body's natural ability to heal itself, was used in the research described herein to fabricate bone scaffolds using the selective laser sintering (SLS) process. 13-93 glass mixed with stearic acid (as the polymer binder) by ball milling was used as the powder feedstock for the SLS machine. The fabricated green scaffolds underwent binder burnout to remove the stearic acid binder and were then sintered at temperatures between 675 °C and 695 °C. The sintered scaffolds had pore sizes ranging from 300 to 800 µm with 50% apparent porosity and an average compressive strength of 20.4 MPa, which is excellent for non-load bearing applications and among the highest reported for an interconnected porous scaffold fabricated with bioactive glasses using the SLS process. The MTT labeling experiment and measurements of MTT formazan formation are evidence that the rough surface of SLS scaffolds provides a cell-friendly surface capable of supporting robust cell growth. PMID:21636879

Kolan, Krishna C R; Leu, Ming C; Hilmas, Gregory E; Brown, Roger F; Velez, Mariano

2011-06-02

9

Bioactive glass-based composites for the production of dense sintered bodies and porous scaffolds.  

PubMed

Recently several attempts have been made to combine calcium phosphates, such as ?-tricalcium phosphate (?-TCP) and, most of all, hydroxyapatite (HA), with bioactive glasses of different composition, in order to develop composites with improved biological and mechanical performance. Unfortunately, the production of such systems usually implies a high-temperature treatment (up to 1300 °C), which may result in several drawbacks, including crystallization of the original glass, decomposition of the calcium phosphate phase and/or reactions between the constituent phases, with non-trivial consequences in terms of microstructure, bioactivity and mechanical properties of the final samples. In the present contribution, novel binary composites have been obtained by sintering a bioactive glass, characterized by a low tendency to crystallize, with the addition of HA or ?-TCP as the second phase. In particular, the composites have been treated at a relatively low temperature (818 °C and 830 °C, depending on the sample), thus preserving the amorphous structure of the glass and minimizing the interaction between the constituent phases. The effects of the glass composition, calcium phosphate nature and processing conditions on the composite microstructure, mechanical properties and in vitro bioactivity have been systematically discussed. To conclude, a feasibility study to obtain scaffolds for bone tissue regeneration has been proposed. PMID:23498242

Bellucci, D; Sola, A; Cannillo, V

2013-01-21

10

Proliferation, differentiation and gene expression of osteoblasts in boron-containing associated with dexamethasone deliver from mesoporous bioactive glass scaffolds  

Microsoft Academic Search

Boron is one of the trace elements in the human body which plays an important role in bone growth. Porous mesopore bioactive glass (MBG) scaffolds are proposed as potential bone regeneration materials due to their excellent bioactivity and drug-delivery ability. The aims of the present study were to develop boron-containing MBG (B-MBG) scaffolds by sol–gel method and to evaluate the

Chengtie Wu; Richard Miron; Anton Sculean; Stefan Kaskel; Thomas Doert; Renate Schulze; Yufeng Zhang

2011-01-01

11

Optimization of composition, structure and mechanical strength of bioactive 3-D glass-ceramic scaffolds for bone substitution.  

PubMed

Fabrication of 3-D highly porous, bioactive, and mechanically competent scaffolds represents a significant challenge of bone tissue engineering. In this work, Bioglass®-derived glass-ceramic scaffolds actually fulfilling this complex set of requirements were successfully produced through the sponge replication method. Scaffold processing parameters and sintering treatment were carefully designed in order to obtain final porous bodies with pore content (porosity above 70 %vol), trabecular architecture and mechanical properties (compressive strength up to 3?MPa) analogous to those of the cancellous bone. Influence of the Bioglass® particles size on the structural and mechanical features of the sintered scaffolds was considered and discussed. Relationship between porosity and mechanical strength was investigated and modeled. Three-dimensional architecture, porosity, mechanical strength and in vitro bioactivity of the optimized Bioglass®-derived scaffolds were also compared to those of CEL2-based glass-ceramic scaffolds (CEL2 is an experimental bioactive glass originally developed by the authors at Politecnico di Torino) fabricated by the same processing technique, in an attempt at understanding the role of different bioactive glass composition on the major features of scaffolds prepared by the same method. PMID:22207602

Baino, Francesco; Ferraris, Monica; Bretcanu, Oana; Verné, Enrica; Vitale-Brovarone, Chiara

2011-12-29

12

Bone regeneration in rat calvarial defects implanted with fibrous scaffolds composed of a mixture of silicate and borate bioactive glasses.  

PubMed

Previous studies have evaluated the capacity of porous scaffolds composed of a single bioactive glass to regenerate bone. In the present study, scaffolds composed of a mixture of two different bioactive glasses (silicate 13-93 and borate 13-93B3) were created and evaluated for their response to osteogenic MLO-A5 cells in vitro and their capacity to regenerate bone in rat calvarial defects in vivo. The scaffolds, which have similar microstructures (porosity=58-67%) and contain 0, 25, 50 and 100wt.% 13-93B3 glass, were fabricated by thermally bonding randomly oriented short fibers. The silicate 13-93 scaffolds showed a better capacity to support cell proliferation and alkaline phosphatase activity than the scaffolds containing borate 13-93B3 fibers. The amount of new bone formed in the defects implanted with the 13-93 scaffolds at 12weeks was 31%, compared to values of 25, 17 and 20%, respectively, for the scaffolds containing 25, 50 and 100% 13-93B3 glass. The amount of new bone formed in the 13-93 scaffolds was significantly higher than in the scaffolds containing 50 and 100% 13-93B3 glass. While the 13-93 fibers were only partially converted to hydroxyapatite at 12weeks, the 13-93B3 fibers were fully converted and formed a tubular morphology. Scaffolds composed of an optimized mixture of silicate and borate bioactive glasses could provide the requisite architecture to guide bone regeneration combined with a controllable degradation rate that could be beneficial for bone and tissue healing. PMID:23827095

Gu, Yifei; Huang, Wenhai; Rahaman, Mohamed N; Day, Delbert E

2013-07-01

13

Copper-releasing, boron-containing bioactive glass-based scaffolds coated with alginate for bone tissue engineering.  

PubMed

The aim of this study was to synthesize and characterize new boron-containing bioactive glass-based scaffolds coated with alginate cross-linked with copper ions. A recently developed bioactive glass powder with nominal composition (wt.%) 65 SiO2, 15 CaO, 18.4 Na2O, 0.1 MgO and 1.5 B2O3 was fabricated as porous scaffolds by the foam replica method. Scaffolds were alginate coated by dipping them in alginate solution. Scanning electron microscopy investigations indicated that the alginate effectively attached on the surface of the three-dimensional scaffolds leading to a homogeneous coating. It was confirmed that the scaffold structure remained amorphous after the sintering process and that the alginate coating improved the scaffold bioactivity and mechanical properties. Copper release studies showed that the alginate-coated scaffolds allowed controlled release of copper ions. The novel copper-releasing composite scaffolds represent promising candidates for bone regeneration. PMID:22040685

Erol, M M; Mouri?o, V; Newby, P; Chatzistavrou, X; Roether, J A; Hupa, L; Boccaccini, Aldo R

2011-10-17

14

Mechanical properties of bioactive glass (13-93) scaffolds fabricated by robotic deposition for structural bone repair.  

PubMed

There is a need to develop synthetic scaffolds to repair large defects in load-bearing bones. Bioactive glasses have attractive properties as a scaffold material for bone repair, but data on their mechanical properties are limited. The objective of the present study was to comprehensively evaluate the mechanical properties of strong porous scaffolds of silicate 13-93 bioactive glass fabricated by robocasting. As-fabricated scaffolds with a grid-like microstructure (porosity 47%, filament diameter 330?m, pore width 300?m) were tested in compressive and flexural loading to determine their strength, elastic modulus, Weibull modulus, fatigue resistance, and fracture toughness. Scaffolds were also tested in compression after they were immersed in simulated body fluid (SBF) in vitro or implanted in a rat subcutaneous model in vivo. As fabricated, the scaffolds had a strength of 86±9MPa, elastic modulus of 13±2GPa, and a Weibull modulus of 12 when tested in compression. In flexural loading the strength, elastic modulus, and Weibull modulus were 11±3MPa, 13±2GPa, and 6, respectively. In compression, the as-fabricated scaffolds had a mean fatigue life of ?10(6) cycles when tested in air at room temperature or in phosphate-buffered saline at 37°C under cyclic stresses of 1-10 or 2-20MPa. The compressive strength of the scaffolds decreased markedly during the first 2weeks of immersion in SBF or implantation in vivo, but more slowly thereafter. The brittle mechanical response of the scaffolds in vitro changed to an elasto-plastic response after implantation for longer than 2-4weeks in vivo. In addition to providing critically needed data for designing bioactive glass scaffolds, the results are promising for the application of these strong porous scaffolds in loaded bone repair. PMID:23438862

Liu, Xin; Rahaman, Mohamed N; Hilmas, Gregory E; Bal, B Sonny

2013-02-21

15

Robotic deposition and in vitro characterization of 3D gelatin-bioactive glass hybrid scaffolds for biomedical applications.  

PubMed

The development of inorganic-organic hybrid scaffolds with controllable degradation and bioactive properties is receiving considerable interest for bone and tissue regeneration. The objective of this study was to create hybrid scaffolds of gelatin and bioactive glass (BG) with a controlled, three-dimensional (3D) architecture by a combined sol-gel and robotic deposition (robocasting) method and evaluate their mechanical response, bioactivity, and response to cells in vitro. Inks for robotic deposition of the scaffolds were prepared by dissolving gelatin in a sol-gel precursor solution of the bioactive glass (70SiO2 -25CaO-5P2 O5 ; mol%) and aging the solution to form a gel with the requisite viscosity. After drying and crosslinking, the gelatin-BG scaffolds, with a grid-like architecture (filament diameter ?350 µm; pore width ?550 µm), showed an elasto-plastic response, with a compressive strength of 5.1 ± 0.6 MPa, in the range of values for human trabecular bone (2-12 MPa). When immersed in phosphate-buffered saline, the crosslinked scaffolds rapidly absorbed water (?440% of its dry weight after 2 h) and showed an elastic response at deformations up to ?60%. Immersion of the scaffolds in a simulated body fluid resulted in the formation of a hydroxyapatite-like surface layer within 5 days, indicating their bioactivity in vitro. The scaffolds supported the proliferation, alkaline phosphatase activity, and mineralization of osteogenic MC3T3-E1 cells in vitro, showing their biocompatibility. Altogether, the results indicate that these gelatin-BG hybrid scaffolds with a controlled, 3D architecture of inter-connected pores have potential for use as implants for bone regeneration. PMID:23255226

Gao, Chunxia; Rahaman, Mohamed N; Gao, Qiang; Teramoto, Akira; Abe, Koji

2012-12-18

16

A new potassium-based bioactive glass: Sintering behaviour and possible applications for bioceramic scaffolds  

Microsoft Academic Search

Providing structural support while maintaining bioactivity is one of the most important goals for bioceramic scaffolds, i.e. artificial templates which guide cells to grow in a 3D pattern, facilitating the formation of functional tissues. In the last few years, 45S5 Bioglass® has been widely investigated as scaffolding material, mainly for its ability to bond to both hard and soft tissues.

Devis Bellucci; Valeria Cannillo; Antonella Sola

2011-01-01

17

Porous and strong bioactive glass (13-93) scaffolds prepared by unidirectional freezing of camphene-based suspensions.  

PubMed

Scaffolds of 13-93 bioactive glass (6Na(2)O, 12K(2)O, 5MgO, 20CaO, 4P(2)O(5), 53SiO(2); wt.%) with an oriented pore architecture were formed by unidirectional freezing of camphene-based suspensions, followed by thermal annealing of the frozen constructs to grow the camphene crystals. After sublimation of the camphene, the constructs were sintered (1 h at 700°C) to produce a dense glass phase with oriented macropores. The objective of this work was to study how constant freezing rates (1-7°C min(-1)) during the freezing step influenced the pore orientation and mechanical response of the scaffolds. When compared to scaffolds prepared by freezing the suspensions on a substrate kept at a constant temperature of 3°C (time-dependent freezing rate), higher freezing rates resulted in better pore orientation, a more homogeneous microstructure and a marked improvement in the mechanical response of the scaffolds in compression. Scaffolds fabricated using a constant freezing rate of 7°C min(-1) (porosity=50±4%; average pore diameter=100 ?m), had a compressive strength of 47±5 MPa and an elastic modulus of 11±3 GPa (in the orientation direction). In comparison, scaffolds prepared by freezing on the constant-temperature substrate had strength and modulus values of 35±11 MPa and 8±3 GPa, respectively. These oriented bioactive glass scaffolds prepared by the constant freezing rate route could potentially be used for the repair of defects in load-bearing bones, such as segmental defects in the long bones. PMID:21855661

Liu, Xin; Rahaman, Mohamed N; Fu, Qiang; Tomsia, Antoni P

2011-08-05

18

Bioactive glass in tissue engineering  

PubMed Central

This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed.

Rahaman, Mohamed N.; Day, Delbert E.; Bal, B. Sonny; Fu, Qiang; Jung, Steven B.; Bonewald, Lynda F.; Tomsia, Antoni P.

2011-01-01

19

Characterizing the hierarchical structures of bioactive sol-gel silicate glass and hybrid scaffolds for bone regeneration.  

PubMed

Bone is the second most widely transplanted tissue after blood. Synthetic alternatives are needed that can reduce the need for transplants and regenerate bone by acting as active temporary templates for bone growth. Bioactive glasses are one of the most promising bone replacement/regeneration materials because they bond to existing bone, are degradable and stimulate new bone growth by the action of their dissolution products on cells. Sol-gel-derived bioactive glasses can be foamed to produce interconnected macropores suitable for tissue ingrowth, particularly cell migration and vascularization and cell penetration. The scaffolds fulfil many of the criteria of an ideal synthetic bone graft, but are not suitable for all bone defect sites because they are brittle. One strategy for improving toughness of the scaffolds without losing their other beneficial properties is to synthesize inorganic/organic hybrids. These hybrids have polymers introduced into the sol-gel process so that the organic and inorganic components interact at the molecular level, providing control over mechanical properties and degradation rates. However, a full understanding of how each feature or property of the glass and hybrid scaffolds affects cellular response is needed to optimize the materials and ensure long-term success and clinical products. This review focuses on the techniques that have been developed for characterizing the hierarchical structures of sol-gel glasses and hybrids, from atomic-scale amorphous networks, through the covalent bonding between components in hybrids and nanoporosity, to quantifying open macroporous networks of the scaffolds. Methods for non-destructive in situ monitoring of degradation and bioactivity mechanisms of the materials are also included. PMID:22349249

Martin, R A; Yue, S; Hanna, J V; Lee, P D; Newport, R J; Smith, M E; Jones, J R

2012-03-28

20

Delivery of dimethyloxallyl glycine in mesoporous bioactive glass scaffolds to improve angiogenesis and osteogenesis of human bone marrow stromal cells.  

PubMed

Development of hypoxia-mimicking bone tissue engineering scaffolds is of great importance in stimulating angiogenesis for bone regeneration. Dimethyloxallyl glycine (DMOG) is a cell-permeable, competitive inhibitor of hypoxia-inducible factor prolyl hydroxylase (HIF-PH), which can stabilize hypoxia-inducible factor 1? (HIF-1?) expression. The aim of this study was to develop hypoxia-mimicking scaffolds by delivering DMOG in mesoporous bioactive glass (MBG) scaffolds and to investigate whether the delivery of DMOG could induce a hypoxic microenvironment for human bone marrow stromal cells (hBMSC). MBG scaffolds with varied mesoporous structures (e.g. surface area and mesopore volume) were prepared by controlling the contents of mesopore-template agent. The composition, large-pore microstructure and mesoporous properties of MBG scaffolds were characterized. The effect of mesoporous properties on the loading and release of DMOG in MBG scaffolds was investigated. The effects of DMOG delivery on the cell morphology, cell viability, HIF-1? stabilization, vascular endothelial growth factor (VEGF) secretion and bone-related gene expression (alkaline phosphatase, ALP; osteocalcin, OCN; and osteopontin, OPN) of hBMSC in MBG scaffolds were systematically investigated. The results showed that the loading and release of DMOG in MBG scaffolds can be efficiently controlled by regulating their mesoporous properties via the addition of different contents of mesopore-template agent. DMOG delivery in MBG scaffolds had no cytotoxic effect on the viability of hBMSC. DMOG delivery significantly induced HIF-1? stabilization, VEGF secretion and bone-related gene expression of hBMSC in MBG scaffolds in which DMOG counteracted the effect of HIF-PH and stabilized HIF-1? expression under normoxic condition. Furthermore, it was found that MBG scaffolds with slow DMOG release significantly enhanced the expression of bone-related genes more than those with instant DMOG release. The results suggest that the controllable delivery of DMOG in MBG scaffolds can mimic a hypoxic microenvironment, which not only improves the angiogenic capacity of hBMSC, but also enhances their osteogenic differentiation. PMID:23811216

Wu, Chengtie; Zhou, Yinghong; Chang, Jiang; Xiao, Yin

2013-06-26

21

Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. I. Preparation and in vitro degradation.  

PubMed

Bioactive glass scaffolds with a microstructure similar to that of dry human trabecular bone but with three different compositions were evaluated for potential applications in bone repair. The preparation of the scaffolds and the effect of the glass composition on the degradation and conversion of the scaffolds to a hydroxyapatite (HA)-type material in a simulated body fluid (SBF) are reported here (Part I). The in vitro response of osteogenic cells to the scaffolds and the in vivo evaluation of the scaffolds in a rat subcutaneous implantation model are described in Part II. Scaffolds (porosity = 78-82%; pore size = 100-500 microm) were prepared using a polymer foam replication technique. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. The conversion rate of the scaffolds to HA in the SBF increased markedly with the B2O3 content of the glass. Concurrently, the pH of the SBF also increased with the B2O3 content of the scaffolds. The compressive strengths of the as-prepared scaffolds (5-11 MPa) were in the upper range of values reported for trabecular bone, but they decreased markedly with immersion time in the SBF and with increasing B2O3 content of the glass. The results show that scaffolds with a wide range of bioactivity and degradation rate can be achieved by replacing varying amounts of SiO(2) in silicate bioactive glass with B2O3. PMID:20544804

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

2010-10-01

22

Effects of chitosan and bioactive glass modifications of knitted and rolled polylactide-based 96/4?L/D scaffolds on chondrogenic differentiation of adipose stem cells.  

PubMed

The performance of biodegradable knitted and rolled 3-dimensional (3D) polylactide-based 96/4 scaffolds modified with bioactive glass (BaG) 13-93, chitosan and both was compared with regard to the viability, proliferation and chondrogenic differentiation of rabbit adipose stem cells (ASCs). Scaffold porosities were determined by micro-computed tomography (?CT). Water absorption and degradation of scaffolds were studied during 28-day hydrolysis in Tris-buffer. Viability, number and differentiation of ASCs in PLA96/4 scaffolds were examined in vitro. The dimensions of the scaffolds were maintained during hydrolysis and mass loss was detected only in the BaG13-93 containing scaffolds. ASCs adhered and proliferated on each scaffold type. Cell aggregation and expression of chondral matrix components improved in all scaffold types in chondrogenic medium. Signs of hypertrophy were detected in the modified scaffolds but not in the plain PLA96/4 scaffold. Chondrogenic differentiation was most enhanced in the presence of chitosan. These findings indicate that the plain P scaffold provided a good 3D-matrix for ASC proliferation whereas the addition of chitosan to the PLA96/4 scaffold induced chondrogenic differentiation independent of the medium. Accordingly, a PLA96/4 scaffold modified by chitosan could provide a functional and bioactive basis for tissue-engineered chondral implants. Copyright © 2012 John Wiley & Sons, Ltd. PMID:23086809

Ahtiainen, Katja; Sippola, Laura; Nurminen, Manu; Mannerström, Bettina; Haimi, Suvi; Suuronen, Riitta; Hyttinen, Jari; Ylikomi, Timo; Kellomäki, Minna; Miettinen, Susanna

2012-10-22

23

Evaluation of 3D nano–macro porous bioactive glass scaffold for hard tissue engineering  

Microsoft Academic Search

Recently, nano–macro dual-porous, three-dimensional (3D) glass structures were developed for use as bioscaffolds for hard\\u000a tissue regeneration, but there have been concerns regarding the interconnectivity and homogeneity of nanopores in the scaffolds,\\u000a as well as the cytotoxicity of the environment deep inside due to limited fluid access. Therefore, mercury porosimetry, nitrogen\\u000a absorption, and TEM have been used to characterize nanopore

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

2011-01-01

24

Three-dimensional printing of hierarchical and tough mesoporous bioactive glass scaffolds with a controllable pore architecture, excellent mechanical strength and mineralization ability.  

PubMed

New generation biomaterials for bone regeneration should be highly bioactive, resorbable and mechanically strong. Mesoporous bioactive glass (MBG), a novel bioactive material, has been used to study bone regeneration due to its excellent bioactivity, degradation and drug delivery ability, however, the construction of three-dimensional (3-D) MBG scaffolds (as for other bioactive inorganic scaffolds) for bone regeneration remains a significant challenge due to their inherent brittleness and low strength. In this brief communication we report a new facile method to prepare hierarchical and multifunctional MBG scaffolds with a controllable pore architecture, excellent mechanical strength and mineralization ability for application in bone regeneration by a modified 3-D printing technique using polyvinylalcohol (PVA) as a binder. The method provides a new way to solve commonly existing issues for inorganic scaffold materials, for example, uncontrollable pore architectures, low strength, high brittleness and the requirement for a second sintering at high temperature. The 3-D printed MBG scaffolds obtained possess a high mechanical strength about 200 times that of traditional polyurethane foam templated MBG scaffolds. They have a highly controllable pore architecture, excellent apatite mineralization ability and sustained drug delivery properties. Our study indicates that 3-D printed MBG scaffolds may be an excellent candidate for bone regeneration. PMID:21402182

Wu, Chengtie; Luo, Yongxiang; Cuniberti, Gianaurelio; Xiao, Yin; Gelinsky, Michael

2011-03-12

25

Enhanced bone regeneration in rat calvarial defects implanted with surface-modified and BMP-loaded bioactive glass (13-93) scaffolds.  

PubMed

The repair of large bone defects, such as segmental defects in the long bones of the limbs, is a challenging clinical problem. Our recent work has shown the ability to create porous scaffolds of silicate 13-93 bioactive glass by robocasting which have compressive strengths comparable to human cortical bone. The objective of this study was to evaluate the capacity of those strong porous scaffolds with a grid-like microstructure (porosity=50%; filament width=330?m; pore width=300?m) to regenerate bone in a rat calvarial defect model. Six weeks post-implantation, the amount of new bone formed within the implants was evaluated using histomorphometric analysis. The amount of new bone formed in implants composed of the as-fabricated scaffolds was 32% of the available pore space (area). Pretreating the as-fabricated scaffolds in an aqueous phosphate solution for 1, 3 and 6days to convert a surface layer to hydroxyapatite prior to implantation enhanced new bone formation to 46%, 57% and 45%, respectively. New bone formation in scaffolds pretreated for 1, 3 and 6days and loaded with bone morphogenetic protein-2 (BMP-2) (1?g per defect) was 65%, 61% and 64%, respectively. The results show that converting a surface layer of the glass to hydroxyapatite or loading the surface-treated scaffolds with BMP-2 can significantly improve the capacity of 13-93 bioactive glass scaffolds to regenerate bone in an osseous defect. Based on their mechanical properties evaluated previously and their capacity to regenerate bone found in this study, these 13-93 bioactive glass scaffolds, pretreated or loaded with BMP-2, are promising in structural bone repair. PMID:23567939

Liu, Xin; Rahaman, Mohamed N; Liu, Yongxing; Bal, B Sonny; Bonewald, Lynda F

2013-04-06

26

Antibacterial and bioactive alpha- and beta-chitin hydrogel/nanobioactive glass ceramic/nano silver composite scaffolds for periodontal regeneration.  

PubMed

Alveolar bone loss and bone defects are the commonly encountered periodontal problems. Large defects do not heal spontaneously and thus require surgical interventions with bone substitutes. Bone grafts have the disadvantages of eliciting an immunologic response with subsequent graft rejection. The success rate of Guided Tissue Regeneration (GTR) is variable because of high susceptibility to infection. Thus emerged the important role of synthetic biomaterials and hence for this purpose we developed a nanocomposite scaffold, using alpha- and beta-chitin hydrogel with bioactive glass ceramic nanoparticles (nBGC) and silver nanoparticles (nAg) by lyophilization technique (aalpha and beta-chitin hydrogel/nBGC/nAg nanocomposite scaffold). The prepared nanoparticles and nanocomposite scaffolds were characterized. In addition, the porosity, swelling, mechanical properties, antibacterial activity, in vitro degradation and biomineralization, cell viability, cell attachment and cell proliferation ability of the prepared composite scaffolds were also evaluated. The results showed that alpha- and beta-chitin/nBGC/nAg composite scaffolds were porous and have the capacity to absorb fluids and swell. The composite scaffolds also showed enhanced antibacterial activity, bioactivity and controlled degradation in comparison to the control scaffolds. Cell viability studies proved the non-toxic nature of the nanocomposite scaffolds. Cell attachment and cell proliferation studies revealed the attachment and spreading nature of cells. All these studies revealed that, these antibacterial nanocomposite scaffolds could be a promising approach for the management of periodontal defects. PMID:24059080

Srinivasan, Sowmya; Kumar, P T Sudheesh; Nair, Sreeja V; Nair, Shantikumar V; Chennazhi, K P; Jayakumar, R

2013-11-01

27

Strontium-containing mesoporous bioactive glass scaffolds with improved osteogenic/cementogenic differentiation of periodontal ligament cells for periodontal tissue engineering.  

PubMed

To achieve the ultimate goal of periodontal tissue engineering, it is of great importance to develop bioactive scaffolds which can stimulate the osteogenic/cementogenic differentiation of periodontal ligament cells (PDLCs) for the favorable regeneration of alveolar bone, root cementum and periodontal ligament. Strontium (Sr) and Sr-containing biomaterials have been found to induce osteoblast activity. However, there has been no systematic report about the interaction between Sr or Sr-containing biomaterials and PDLCs for periodontal tissue engineering. The aims of this study were to prepare Sr-containing mesoporous bioactive glass (Sr-MBG) scaffolds and investigate whether the addition of Sr could stimulate osteogenic/cementogenic differentiation of PDLCs in a tissue-engineering scaffold system. The composition, microstructure and mesopore properties (specific surface area, nanopore volume and nanopore distribution) of Sr-MBG scaffolds were characterized. The proliferation, alkaline phosphatase (ALP) activity and osteogenesis/cementogenesis-related gene expression (ALP, Runx2, Col I, OPN and CEMP1) of PDLCs on different kinds of Sr-MBG scaffolds were systematically investigated. The results show that Sr plays an important role in influencing the mesoporous structure of MBG scaffolds in which high contents of Sr decreased the well-ordered mesopores as well as their surface area/pore volume. Sr(2+) ions could be released from Sr-MBG scaffolds in a controlled way. The incorporation of Sr into MBG scaffolds has significantly stimulated ALP activity and osteogenesis/cementogenesis-related gene expression of PDLCs. Furthermore, Sr-MBG scaffolds in a simulated body fluid environment still maintained excellent apatite-mineralization ability. The study suggests that the incorporation of Sr into MBG scaffolds is a viable way to stimulate the biological response of PDLCs. Sr-MBG scaffolds are a promising bioactive material for periodontal tissue-engineering applications. PMID:22750735

Wu, Chengtie; Zhou, Yinghong; Lin, Chucheng; Chang, Jiang; Xiao, Yin

2012-06-28

28

Bioactivity of degradable polymer sutures coated with bioactive glass.  

PubMed

Novel bioactive materials have been prepared by coating violet resorbable Vicryl sutures with a bioactive glass powder derived from a co-precipitation method. Two techniques have been chosen for the composite preparation: pressing the sutures in a bed of glass powder and slurry-dipping of sutures in liquid suspensions of bioactive glass powders. The uniformity and thickness of the coatings obtained by the two methods were compared. The bioactivity of the sutures with and without bioactive glass coating was tested by soaking in an inorganic acellular simulated body fluid (SBF). The composite sutures were characterised by XRD, SEM and FTIR analyses before and after soaking in SBF solution to assess the formation of hydroxyapatite on their surfaces, which is a qualitative measure of their bioactivity. The possible use of bioactive sutures to produce tissue engineering scaffolds and as reinforcement of resorbable calcium phosphates is discussed. PMID:15477741

Bretcanu, Oana; Verné, Enrica; Borello, Luisa; Boccaccini, Aldo R

2004-08-01

29

Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation.  

PubMed

In Part I, the in vitro degradation of bioactivAR52115e glass scaffolds with a microstructure similar to that of human trabecular bone, but with three different compositions, was investigated as a function of immersion time in a simulated body fluid. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. This work is an extension of Part I, to investigate the effect of the glass composition on the in vitro response of osteogenic MLO-A5 cells to these scaffolds, and on the ability of the scaffolds to support tissue infiltration in a rat subcutaneous implantation model. The results of assays for cell viability and alkaline phosphatase activity showed that the slower degrading silicate 13-93 and borosilicate 13-93B1 scaffolds were far better than the borate 13-93B3 scaffolds in supporting cell proliferation and function. However, all three groups of scaffolds showed the ability to support tissue infiltration in vivo after implantation for 6 weeks. The results indicate that the required bioactivity and degradation rate may be achieved by substituting an appropriate amount of SiO2 in 13-93 glass with B2O3, and that these trabecular glass scaffolds could serve as substrates for the repair and regeneration of contained bone defects. PMID:20540099

Fu, Qiang; Rahaman, Mohamed N; Bal, B Sonny; Bonewald, Lynda F; Kuroki, Keiichi; Brown, Roger F

2010-10-01

30

Oriented bioactive glass (13-93) scaffolds with controllable pore size by unidirectional freezing of camphene-based suspensions: Microstructure and mechanical response.  

PubMed

Scaffolds of 13-93 bioactive glass (composition 6.0 Na?O, 7.9 K?O, 7.7 MgO, 22.1 CaO, 1.7 P?O?, 54.6 SiO? (mol.%)) containing oriented pores of controllable diameter were prepared by unidirectional freezing of camphene-based suspensions (10 vol.% particles) on a cold substrate (-196 °C or 3 °C). By varying the annealing time (0-72 h) to coarsen the camphene phase, constructs with the same porosity (86 ± 1%) but with controllable pore diameters (15-160 ?m) were obtained after sublimation of the camphene. The pore diameters had a self-similar distribution that could be fitted by a diffusion-controlled coalescence model. Sintering (1 h at 690 °C) was accompanied by a decrease in porosity and pore diameter, the magnitude of which depended on the pore size of the green constructs, giving scaffolds with a porosity of 20-60% and average pore diameter of 6-120 ?m. The compressive stress vs. deformation response of the sintered scaffolds in the orientation direction was linear, followed by failure. The compressive strength and elastic modulus in the orientation direction varied from 180 MPa and 25 GPa (porosity=20%) to 16 MPa and 4 GPa (porosity=60%), respectively, which were 2-3 times larger than the values in the direction perpendicular to the orientation. The potential use of these 13-93 bioactive glass scaffolds for the repair of large defects in load-bearing bones, such as segmental defects in long bones, is discussed. PMID:20807594

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

2010-08-31

31

Nanostructured poly(vinyl alcohol)\\/bioactive glass and poly(vinyl alcohol)\\/chitosan\\/bioactive glass hybrid scaffolds for biomedical applications  

Microsoft Academic Search

Bone tissue engineering is the field of intense research for developing new 3D scaffolds with hierarchical and highly interconnected porous structure, which should match the properties of the tissue that is to be replaced. These materials need to be biocompatible, ideally osteoinductive, osteoconductive and mechanically well-matched. In the present study, we report the development and characterization of novel hybrid macroporous

Herman S. Mansur; Hermes S. Costa

2008-01-01

32

Broad-Spectrum Bactericidal Activity of Ag2O-Doped Bioactive Glass  

Microsoft Academic Search

Bioactive glass has found extensive application as an orthopedic and dental graft material and most recently also as a tissue engineering scaffold. Here we report an initial investigation of the in vitro antibacterial properties of AgBG, a novel bioactive glass composition doped with Ag2O. The bacteriostatic and bactericidal properties of this new material and of two other bioactive glass compositions,

Maria Bellantone; Huw D. Williams; Larry L. Hench

2002-01-01

33

Composite surgical sutures with bioactive glass coating.  

PubMed

A processing method was developed to coat polyglactin 910 (Vicryl) sutures with bioactive glass powder (45S5 Bioglass). High reproducibility and homogeneity of the coating in terms of microstructure and thickness along the suture length were achieved. Bioglass-coated sutures exhibited a high level of chemical reactivity in simulated body fluid (SBF), indicating their bioactive behavior. This was evident by the prompt formation of hydroxyapatite (HA) crystals on the surface after only 7 days of immersion in SBF. These crystals grew to form a thick HA layer (15 microm thickness) after 3 weeks in SBF. The tensile strength of the sutures was tested before and after immersion in SBF in order to assess the effect of the bioactive glass coating on suture degradation. The tensile strength of composite sutures was lower than that of as-received Vicryl sutures, 385 and 467 MPa, respectively. However, after 28 days of immersion in SBF the residual tensile strengths of coated and uncoated sutures were similar (83 and 88 MPa, respectively), indicating no negative effect of the HA layer formation on the suture strength. The effect of bioactive glass coating on the polymer degradation is discussed. The developed bioactive sutures represent interesting materials for applications in wound healing, fabrication of fibrous three-dimensional scaffolds for tissue engineering, and reinforcement elements for calcium-phosphate temporary implants. PMID:14528459

Boccaccini, Aldo R; Stamboulis, Artemis G; Rashid, Azrina; Roether, Judith A

2003-10-15

34

Biomimetic component coating on 3D scaffolds using high bioactivity of mesoporous bioactive ceramics  

PubMed Central

Background Mesoporous bioactive glasses (MBGs) are very attractive materials for use in bone tissue regeneration because of their extraordinarily high bone-forming bioactivity in vitro. That is, MBGs may induce the rapid formation of hydroxy apatite (HA) in simulated body fluid (SBF), which is a major inorganic component of bone extracellular matrix (ECM) and comes with both good osteoconductivity and high affinity to adsorb proteins. Meanwhile, the high bioactivity of MBGs may lead to an abrupt initial local pH variation during the initial Ca ion-leaching from MBGs at the initial transplant stage, which may induce unexpected negative effects on using them in in vivo application. In this study we suggest a new way of using MBGs in bone tissue regeneration that can improve the strength and make up for the weakness of MBGs. We applied the outstanding bone-forming bioactivity of MBG to coat the main ECM components HA and collagen on the MBG-polycarplolactone (PCL) composite scaffolds for improving their function as bone scaffolds in tissue regeneration. This precoating process can also expect to reduce initial local pH variation of MBGs. Methods and materials The MBG-PCL scaffolds were immersed in the mixed solution of the collagen and SBF at 37°C for 24 hours. The coating of ECM components on the MBG-PCL scaffolds and the effect of ECM coating on in vitro cell behaviors were confirmed. Results The ECM components were fully coated on MBG-PCL scaffolds after immersing in SBF containing dilute collagen-I solution only for 24 hours due to the high bone-forming bioactivity of MBG. Both cell affinity and osteoconductivity of MBG-PCL scaffolds were dramatically enhanced by this precoating process. Conclusion The precoating process of ECM components on MBG-PCL scaffold using a high bioactivity of MBG was not only effective in enhancing the functionality of scaffolds but also effective in eliminating the unexpected side effect. The MBG-PCL scaffold-coated ECM components ideally satisfied the required conditions of scaffold in tissue engineering, including 3D well-interconnected pore structures with high porosity, good bioactivity, enhanced cell affinity, biocompatibility, osteoconductivity, and sufficient mechanical properties, and promise excellent potential application in the field of biomaterials.

Yun, Hui-suk; Kim, Sang-Hyun; Khang, Dongwoo; Choi, Jungil; Kim, Hui-hoon; Kang, Minji

2011-01-01

35

Factors affecting crystallization of bioactive glasses  

Microsoft Academic Search

The product range of bioactive glasses is restricted by their tendency to crystallize at working processes typically performed with high viscosity melts. In this work high-temperature properties viscosity, devitrification temperature and liquidus temperature of seven bioactive glasses are measured. Further, the parameters used to describe glass stability and crystallization tendency are discussed. The results indicate that bioactive glasses can be

Hanna Arstila; Erik Vedel; Leena Hupa; Mikko Hupa

2007-01-01

36

Review of bioactive glass: from Hench to hybrids.  

PubMed

Bioactive glasses are reported to be able to stimulate more bone regeneration than other bioactive ceramics but they lag behind other bioactive ceramics in terms of commercial success. Bioactive glass has not yet reached its potential but research activity is growing. This paper reviews the current state of the art, starting with current products and moving onto recent developments. Larry Hench's 45S5 Bioglass® was the first artificial material that was found to form a chemical bond with bone, launching the field of bioactive ceramics. In vivo studies have shown that bioactive glasses bond with bone more rapidly than other bioceramics, and in vitro studies indicate that their osteogenic properties are due to their dissolution products stimulating osteoprogenitor cells at the genetic level. However, calcium phosphates such as tricalcium phosphate and synthetic hydroxyapatite are more widely used in the clinic. Some of the reasons are commercial, but others are due to the scientific limitations of the original Bioglass 45S5. An example is that it is difficult to produce porous bioactive glass templates (scaffolds) for bone regeneration from Bioglass 45S5 because it crystallizes during sintering. Recently, this has been overcome by understanding how the glass composition can be tailored to prevent crystallization. The sintering problems can also be avoided by synthesizing sol-gel glass, where the silica network is assembled at room temperature. Process developments in foaming, solid freeform fabrication and nanofibre spinning have now allowed the production of porous bioactive glass scaffolds from both melt- and sol-gel-derived glasses. An ideal scaffold for bone regeneration would share load with bone. Bioceramics cannot do this when the bone defect is subjected to cyclic loads, as they are brittle. To overcome this, bioactive glass polymer hybrids are being synthesized that have the potential to be tough, with congruent degradation of the bioactive inorganic and the polymer components. Key to this is creating nanoscale interpenetrating networks, the organic and inorganic components of which have covalent coupling between them, which involves careful control of the chemistry of the sol-gel process. Bioactive nanoparticles can also now be synthesized and their fate tracked as they are internalized in cells. This paper reviews the main developments in the field of bioactive glass and its variants, covering the importance of control of hierarchical structure, synthesis, processing and cellular response in the quest for new regenerative synthetic bone grafts. The paper takes the reader from Hench's Bioglass 45S5 to new hybrid materials that have tailorable mechanical properties and degradation rates. PMID:22922331

Jones, Julian R

2012-08-21

37

Bioactive scaffolds mimicking natural dentin structure.  

PubMed

Organic scaffolds of poly(ethyl methacrylate-co-hydroxyethyl acrylate) [P(EMA-co-HEA)] 70/30 wt % ratio, with varying proportions of silica SiO(2) from 0 to 20 wt % and aligned tubular pores, were prepared using a fiber-templating fabrication method, with the aim of mimicking structure and properties of the mineralized tissue of natural dentin. Precursors of the copolymer and silica were simultaneously polymerized in a sol-gel process within the fiber template, which was eventually eliminated to generate homogeneously distributed parallel micrometer-sized pores in the material. Scaffolds of PEMA and PHEA were obtained by the same approach. The scaffolds were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and thermogravimetric analysis. The specific volume was determined by Archimedes' method and the porosity calculated from the geometry. The mechanical properties were analyzed in tensile and compressive modes. The bioactivity of the scaffolds with 15 wt % SiO(2) was tested by immersion in simulated body fluid (SBF) for 7 days followed by immersion in 2x SBF for 7 days. These scaffolds were afterwards characterized by SEM, energy dispersive spectroscopy, and compression assays. Percentages of silica above 10 wt % reinforced mechanically the copolymer, evidenced by the hindrance of the long range motions of the organic chains, altered shrinkage and swelling, and meanwhile conferred bioactivity to its surface. These tubular porous structures, which resemble natural dentin with regard to its structure and properties and induce the precipitation of apatite on their surfaces in vitro, are expected to facilitate the integration in the host mineralized tissue, to stimulate cell growth and to be useful as guiding scaffolds for in vivo dentin regeneration. PMID:19072987

Lluch, A Vallés; Fernández, A Campillo; Ferrer, G Gallego; Pradas, M Monleón

2009-07-01

38

[Preparation of porous Ti metal composite scaffold with bioactivity].  

PubMed

In this work, the titanium powder was used for preparing highly interconnected porous scaffolds by impregnating polymer method. Subsequently, the electrochemical method and the biomimetic mineralization method were adopted to deposit calcium phosphate coatings on the sintered scaffold which was supposed to improve the scaffold bioactivity. The experimental results show, with the use of the two methods, the scaffolds are successfully covered by the deposition of the nano-net structure calcium phosphate coating, and they hold their three dimensional interconnected porous structures. Therefore, this kind of bioactive composite scaffold with such mechanical strength as that of woven bone should be a promising bone graft in clinical applications. PMID:19813613

Zhao, Jing; Lu, Xiong; Wang, Jianxin; Weng, Jie

2009-08-01

39

Preparation of bioactive porous HA/PCL composite scaffolds  

NASA Astrophysics Data System (ADS)

Porous hydroxyapatite (HA) bioceramic scaffold has been widely attracted the attention to act as a three-dimensional (3D) template for cell adhesion, proliferation, differentiation and thus promoting bone and cartilage regeneration because of its osteoinduction. However, the porous bioceramic scaffold is fragile so that it is not suitable to be applied in clinic for bone repair or replacement. Therefore, it is significant to improve the mechanical property of porous HA bioceramics while the interconnected structure is maintained for tissue ingrowth in vivo. In the present research, a porous composite scaffold composed of HA scaffold and polycaprolactone (PCL) lining was fabricated by the method of polymer impregnating to produce HA scaffold coated with PCL lining. Subsequently, the composite scaffolds were deposited with biomimetic coating for improving the bioactivity. The HA/PCL composite scaffolds with improved mechanical property and bioactivity is expected to be a promising bone substitute in tissue engineering applications.

Zhao, J.; Guo, L. Y.; Yang, X. B.; Weng, J.

2008-12-01

40

Bioactivity and protein attachment onto bioactive glasses containing silver nanoparticles.  

PubMed

There is much interest in silver containing glasses for use in bone replacement owing to the demonstrated antibacterial effect. In this work, 2 and 8 mol % of silver was added during the sol-gel process to the composition of a bioactive glass belonging to CaO-SiO(2 -P(2)O(5) system. The samples were characterized by means of ultraviolet-visible spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques to demonstrate that the silver is embedded into the glass matrix as nanoparticles. Bioactivity test in simulated body fluid proved that the presence of silver in the bioactive glass composition, even in high amount, preserve or even improve the bioactivity of the starting glass, and consequently, leads to the carbonated apatite formation, which is the prerequisite for bioactive materials to bond with living bones. Complementary information proving these findings were delivered by performing X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, and XPS measurements. The presence of silver also improves protein binding capability to the bioactive glass surface as demonstrated by cw-electron paramagnetic resonance experiments and XPS measurements. PMID:22345075

Vulpoi, A; Gruian, C; Vanea, E; Baia, L; Simon, S; Steinhoff, H-J; Göller, G; Simon, V

2012-02-18

41

Alkaline phosphatase grafting on bioactive glasses and glass ceramics  

Microsoft Academic Search

Bone integration of orthopaedic or dental implants and regeneration of damaged bone at the surgical site are still unresolved problems in prosthetic surgery. For this reason, biomimetic surfaces (i.e. both inorganic and biological bioactive surfaces) represent a challenge for bone implantation. In this research work a hydrolase enzyme (alkaline phosphatase) was covalently grafted to inorganic bioactive glass and glass ceramic

Enrica Verné; Sara Ferraris; Chiara Vitale-Brovarone; Silvia Spriano; Claudia L. Bianchi; Alberto Naldoni; Marco Morra; Clara Cassinelli

2010-01-01

42

Surface modification of bioactive glasses and preparation of PDLLA/bioactive glass composite films.  

PubMed

In order to improve the homogeneous dispersion of particles in the polymeric matrix, 45S5, mesoporous 58S, and 58S bioactive glasses were surface modified by esterification reactions with dodecyl alcohol at reflux temperature of 260 degrees C (named as m-45S5, m-mesoporous 58S, and m-58S, respectively). The modified particles showed better hydrophobicity and longer time of suspension in organic matrix. The PDLLA/bioactive glass composite films were fabricated using surface modified bioactive glass particles through solvent casting-evaporation method. Surface morphology, mechanical property, and bioactivity were investigated. The results revealed that the inorganic particle distribution and tensile strength of the composite films with modified bioactive glass particles were significantly improved while great bioactive properties were maintained. Scanning electron microscopy (SEM) observation illustrated that the modified bioactive glass particles were homogeneously dispersed in the PDLLA matrix. The maximum tensile strengths of composite films with modified bioactive glass particles were higher than that of composite films with unmodified bioactive glass particles. The bioactivity of the composite films were evaluated by being soaked in the simulated body fluid (SBF) and the SEM observation of the films suggested that the modified composite films were still bioactive in that they could induce the formation of HAp on its surface and the distribution of HAp was even more homogeneous on the film. The results mentioned above indicated that the surface modification of bioactive glasses with dodecyl alcohol was an effective method to prepare PDLLA/bioactive glass composites with enhanced properties. By studying the comparisons of modification effects among the three types of bioactive glasses, we could get the conclusion that the size and morphology of the inorganic particles would greatly affect the modification effects and the properties of composites. PMID:18801895

Gao, Yuan; Chang, Jiang

2008-09-18

43

Laser cladding of bioactive glass coatings.  

PubMed

Laser cladding by powder injection has been used to produce bioactive glass coatings on titanium alloy (Ti6Al4V) substrates. Bioactive glass compositions alternative to 45S5 Bioglass were demonstrated to exhibit a gradual wetting angle-temperature evolution and therefore a more homogeneous deposition of the coating over the substrate was achieved. Among the different compositions studied, the S520 bioactive glass showed smoother wetting angle-temperature behavior and was successfully used as precursor material to produce bioactive coatings. Coatings processed using a Nd:YAG laser presented calcium silicate crystallization at the surface, with a uniform composition along the coating cross-section, and no significant dilution of the titanium alloy was observed. These coatings maintain similar bioactivity to that of the precursor material as demonstrated by immersion in simulated body fluid. PMID:19671459

Comesaña, R; Quintero, F; Lusquiños, F; Pascual, M J; Boutinguiza, M; Durán, A; Pou, J

2009-08-09

44

Optimization and characterization of bioactive glass nanofibers and nanocomposites  

NASA Astrophysics Data System (ADS)

Disease affects different areas of the bone and can impact individuals of all pathologies and ethnicities. These bone diseases can result in weakening which leads to trauma during ordinary function, the need for reconstructive surgery, and eventual bone replacement. Tissue engineering can provide a less traumatic and more fundamental solution to the current therapies. Bioactive glasses are promising materials in tissue engineering applications because of their ability to form hydroxycarbonate apatite in the presence of simulated body fluid, support cell adhesion, growth, and differentiation, induce bone formation, and concentrate bone morphogenic proteins in vivo. The research in this dissertation will attempt to improve the quality, yield, and toughness of bioactive glass nanofibrous scaffolds. The three specific aims of this research include, (1) Optimization and Characterization of Surfactant Modified Bioactive Glass (2) Optimization of Direct Synthesis Bioactive glass Nanofibers from Sols (3) Mechanical Properties and In-vitro Biomineralization of Bioglass-loaded Polyglyconate Nanocomposites Created Using the Particulate Leaching Method. The purpose of the first specific aim was to optimize the processing of bioactive glass nanofibers, resulting in greater fiber uniformity with a reduction in beading. The increase in viscosity coupled with the ability of the surfactant to limit polymeric secondary bonding led to improved fiber quality. The focal point of the second specific aim is the production of sol-gel derived glass fibers with high bioactivity prepared by electrospinning without the use of any polymer carrier system. Advantages of this method include decreased processing time, increased production of fibers, and a decrease in the loss of material due to the calcining process. The solvent cast/ particulate leaching method was used to create a nanocomposite of bioglass and the co-polymer polyglyconate (MaxonRTM) for bone tissue scaffolds The biocompatibility of the composite foams was observed and calcium phosphate presence was quantified. The incorporation of bioglass into the polymer matrix improved the strength (modulus - 21.47 MPa) and biocompatibility of the polyglyconate foam. Keywords: Bioactive glass, Electrospinning, Solvent Casting/Particulate Leaching Method, Nanocomposites

Scarber, Reginna E.

45

The in-vitro bioactivity of mesoporous bioactive glasses  

Microsoft Academic Search

Ordered mesoporous bioactive glasses (MBGs) with different compositions were prepared by using nonionic block copolymer surfactants as structure-directing agents through an evaporation-induced self-assembly process. Their in-vitro bioactivities were studied in detail by electron microscopy, Fourier-transform infrared spectroscopy, and inductively coupled plasma (ICP) atomic emission spectroscopy. The ICP element analysis results were further calculated in terms of the total consumption of

Xiaoxia Yan; Xiaohui Huang; Chengzhong Yu; Hexiang Deng; Yi Wang; Zhendong Zhang; Shizhang Qiao; Gaoqing Lu; Dongyuan Zhao

2006-01-01

46

Bioactive glass ceramics: properties and applications.  

PubMed

Heat treatment of an MgO-CaO-SiO2-P2O5 glass gave a glass ceramic containing crystalline apatite (Ca10(PO4)6O,F2] and beta-wollastonite (CaO,SiO2) in an MgO-CaO-SiO2 glassy matrix. It showed bioactivity and a fairly high mechanical strength which decreased only slowly, even under load-bearing conditions in the body. It is used clinically as artificial vertebrae, iliac bones, etc. The bioactivity of this glass ceramic was attributed to apatite formation on its surface in the body. Dissolution of calcium and silicate ions from the glass ceramic was considered to play an important role in forming the surface apatite layer. It was shown that some new kinds of bioactive materials can be developed from CaO,SiO2-based glasses. Ceramics, metals and organic polymers coated with bone-like apatite were obtained when such materials were placed in the vicinity of a CaO,SiO2-based glass in a simulated body fluid. A bioactive bone cement which was hardened within 4 min and bonded to living bone, forming an apatite, was obtained by mixing a CaO,SiO2-based glass powder with a neutral ammonium phosphate solution. Its compressive strength reached 80 MPa comparable to that of poly(methyl methacrylate) within 3 d. A bioactive and ferromagnetic glass ceramic containing crystalline magnetite (Fe3O4) in a matrix of CaO,SiO2-based glassy and crystalline phases was obtained by a heat treatment of a Fe2O3-CaO.SiO2-B2O3-P2O5 glass. This glass ceramic was shown to be useful as thermoseeds for hyperthermia treatment of cancer. PMID:1878450

Kokubo, T

1991-03-01

47

Bioactive nanofibrous scaffolds for regenerative endodontics.  

PubMed

Here we report the synthesis, materials characterization, antimicrobial capacity, and cytocompatibility of novel antibiotic-containing scaffolds. Metronidazole (MET) or Ciprofloxacin/(CIP) was mixed with a polydioxanone (PDS)polymer solution at 5 and 25 wt% and processed into fibers. PDS fibers served as a control. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), tensile testing, and high-performance liquid chromatography (HPLC) were used to assess fiber morphology, chemical structure, mechanical properties, and drug release, respectively. Antimicrobial properties were evaluated against those of Porphyromonas gingivalis/Pg and Enterococcus faecalis/Ef. Cytotoxicity was assessed in human dental pulp stem cells (hDPSCs). Statistics were performed, and significance was set at the 5% level. SEM imaging revealed a submicron fiber diameter. FTIR confirmed antibiotic incorporation. The tensile values of hydrated 25 wt% CIP scaffold were significantly lower than those of all other groups. Analysis of HPLC data confirmed gradual, sustained drug release from the scaffolds over 48 hrs. CIP-containing scaffolds significantly (p < .00001) inhibited biofilm growth of both bacteria. Conversely, MET-containing scaffolds inhibited only Pg growth. Agar diffusion confirmed the antimicrobial properties against specific bacteria for the antibiotic-containing scaffolds. Only the 25 wt% CIP-containing scaffolds were cytotoxic. Collectively, this study suggests that polymer-based antibiotic-containing electrospun scaffolds could function as a biologically safe antimicrobial drug delivery system for regenerative endodontics. PMID:24056225

Bottino, M C; Kamocki, K; Yassen, G H; Platt, J A; Vail, M M; Ehrlich, Y; Spolnik, K J; Gregory, R L

2013-09-20

48

Role of bioactive 3D hybrid fibrous scaffolds on mechanical behavior and spatiotemporal osteoblast gene expression.  

PubMed

Three-dimensional (3D) bioactive organic-inorganic (O/I) hybrid fibrous scaffolds are attractive extracellular matrix (ECM) surrogates for bone tissue engineering. With the aim of regulating osteoblast gene expression in 3D, a new class of hybrid fibrous scaffolds with two distinct fiber diameters (260 and 600 nm) and excellent physico-mechanical properties were fabricated from tertiary (SiO2-CaO-P2O5) bioactive glass (BG) and poly (?-caprolactone) (PCL) by in situ sol-gel and electrospinning process. The PCL/BG hybrid fibrous scaffolds exhibited accelerated wetting properties, enhanced pore sizes and porosity, and superior mechanical properties that were dependent on fiber diameter. Contrary to control PCL fibrous scaffolds that were devoid of bonelike apatite particles, incubating PCL/BG hybrid fibrous scaffolds in simulated body fluid (SBF) revealed bonelike apatite deposition. Osteoblast cells cultured on PCL/BG hybrid fibrous scaffolds spread with multiple attachments and actively proliferated suggesting that the low temperature in situ sol-gel and electrospinning process did not have a detrimental effect. Targeted bone-associated gene expressions by rat calvarial osteoblasts seeded on these hybrid scaffolds demonstrated remarkable spatiotemporal gene activation. Transcriptional-level gene expressions for alkaline phosphatase (ALP), osteopontin (OPN), bone sialoprotein (BSP), and osteocalcin (OCN) were significantly higher on the hybrid fibrous scaffolds (p < 0.001) that were largely dependent on fiber diameter compared. Taken together, our results suggest that PCL/BG fibrous scaffolds may accelerate bone formation by providing a favorable microenvironment. PMID:23826710

Allo, Bedilu A; Lin, Shigang; Mequanint, Kibret; Rizkalla, Amin S

2013-07-18

49

Bioinspired Strong and Highly Porous Glass Scaffolds  

PubMed Central

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

Saiz, Eduardo; Tomsia, Antoni P.

2011-01-01

50

Bioactive scaffolds for engineering vascularized cardiac tissues  

PubMed Central

Functional vascularization is a key requirement for the development and function of most tissues, and most critically cardiac muscle. Rapid and irreversible loss of cardiomyocytes during cardiac infarction directly results from the lack of blood supply. Contractile cardiac grafts, engineered using cardiovascular cells in conjunction with biomaterial scaffolds, are an actively studied method for cardiac repair. In this article, we focus on biomaterial scaffolds designed to mediate the development and maturation of vascular networks, by immobilized growth factors. The interactive effects of multiple vasculogenic factors are discussed in the context of cardiac tissue engineering.

Chiu, Loraine; Radisic, Milica; Vunjak-Novakovic, Gordana

2013-01-01

51

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

PubMed

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

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

2009-01-22

52

Biodegradable and bioactive porous polymer\\/inorganic composite scaffolds for bone tissue engineering  

Microsoft Academic Search

Biodegradable polymers and bioactive ceramics are being combined in a variety of composite materials for tissue engineering scaffolds. Materials and fabrication routes for three-dimensional (3D) scaffolds with interconnected high porosities suitable for bone tissue engineering are reviewed. Different polymer and ceramic compositions applied and their impact on biodegradability and bioactivity of the scaffolds are discussed, including in vitro and in

K. Rezwan; Q. Z. Chen; J. J. Blaker; Aldo Roberto Boccaccini

2006-01-01

53

Bioactive scaffold for bone tissue engineering: An in vivo study  

NASA Astrophysics Data System (ADS)

Massive bone loss of the proximal femur is a common problem in revision cases of total hip implants. Allograft is typically used to reconstruct the site for insertion of the new prosthesis. However, for long term fixation and function, it is desirable that the allograft becomes fully replaced by bone tissue and aids in the regeneration of bone to that site. However, allograft use is typically associated with delayed incorporation and poor remodeling. Due to these profound limitations, alternative approaches are needed. Tissue engineering is an attractive approach to designing improved graft materials. By combining osteogenic activity with a resorbable scaffold, bone formation can be stimulated while providing structure and stability to the limb during incorporation and remodeling of the scaffold. Porous, surface modified bioactive ceramic scaffolds (pSMC) have been developed which stimulate the expression of the osteoblastic phenotype and production of bone-like tissue in vitro. The scaffold and two tissue-engineered constructs, osteoprogenitor cells seeded onto scaffolds or cells expanded in culture to form bone tissue on the scaffolds prior to implantation, were investigated in a long bone defect model. The rate of incorporation was assessed. Both tissue-engineered constructs stimulated bone formation and comparable repair at 2 weeks. In a rat femoral window defect model, bone formation increased over time for all groups in concert with scaffold resorption, leading to a 40% increase in bone and 40% reduction of the scaffold in the defect by 12 weeks. Both tissue-engineered constructs enhanced the rate of mechanical repair of long bones due to better bony union with the host cortex. Long bones treated with tissue engineered constructs demonstrated a return in normal torsional properties by 4 weeks as compared to 12 weeks for long bones treated with pSMC. Culture expansion of cells to produce bone tissue in vitro did not accelerate incorporation over the treatment with cells seeded at the time of surgery. Porous, surface modified bioactive ceramic is a promising scaffold material for tissue-engineered bone repair. Bone formation and scaffold resorption act in concert for maintenance and improvement of the structural properties of the long bones over time. As determined histomorphometrically and mechanically, the rate of incorporation of the scaffold was enhanced with the tissue-engineered constructs.

Livingston, Treena Lynne

54

Bioactive glass coatings for orthopedic metallic implants  

SciTech Connect

The objective of this work is to develop bioactive glass coatings for metallic orthopedic implants. A new family of glasses in the SiO2-Na2O-K2O-CaO-MgO-P2O5 system has been synthesized and characterized. The glass properties (thermal expansion, softening and transformation temperatures, density and hardness) are in line with the predictions of established empirical models. The optimized firing conditions to fabricate coatings on Ti-based and Co-Cr alloys have been determined and related to the glass properties and the interfacial reactions. Excellent adhesion to alloys has been achieved through the formation of 100-200 nm thick interfacial layers (Ti5Si3 on Ti-based alloys and CrOx on Co-Cr). Finally, glass coatings, approximately 100 mu m thick, have been fabricated onto commercial Ti alloy-based dental implants.

Lopez-Esteban, Sonia; Saiz, Eduardo; Fujino, Sigheru; Oku, Takeo; Suganuma, Katsuaki; Tomsia, Antoni P.

2003-06-30

55

Bioactive borate glass coatings for titanium alloys.  

PubMed

Bioactive borate glass coatings have been developed for titanium and titanium alloys. Glasses from the Na(2)O-CaO-B(2)O(3) system, modified by additions of SiO(2), Al(2)O(3), and P(2)O(5), were characterized and compositions with thermal expansion matches to titanium were identified. Infrared and X-ray diffraction analyses indicate that a hydroxyapatite surface layer forms on the borate glasses after exposure to a simulated body fluid for 2 weeks at 37 degrees C; similar layers form on 45S5 Bioglass((R)) exposed to the same conditions. Assays with MC3T3-E1 pre-osteoblastic cells show the borate glasses exhibit in vitro biocompatibility similar to that of the 45S5 Bioglass((R)). An enameling technique was developed to form adherent borate glass coatings on Ti6Al4V alloy, with adhesive strengths of 36 +/- 2 MPa on polished substrates. The results show these new borate glasses to be promising candidates for forming bioactive coatings on titanium substrates. PMID:18415004

Peddi, Laxmikanth; Brow, Richard K; Brown, Roger F

2008-04-15

56

Interactions of bioactive glass materials in the oral environment  

Microsoft Academic Search

The aim of this research was to investigate bioactive glass materials for their use in dental restorations. Mechanical properties such as strength, toughness and wear resistance were considered initially, but the focus of this thesis was the biological properties such as reactions with saliva and interactions with natural dental tissues. Bioactive composite materials were created by incorporating bioactive glass and

Sarah Elizabeth Efflandt

2001-01-01

57

Bioactivity of tape cast and sintered bioactive glass-ceramic in simulated body fluid  

Microsoft Academic Search

A common ceramic processing technique, tape casting, was used to produce thin, flexible sheets of bioactive glass (Bioglass® 45S5) particulate in an organic matrix. Tape casting offers the possibility of producing three-dimensional shapes, as the final material is built up layer by layer. Bioactive glass tapes were sintered together to form small discs for in vitro bioactivity testing in simulated

Daniel C. Clupper; John J. Mecholsky; Guy P. LaTorre; David C. Greenspan

2002-01-01

58

Differential alkaline phosphatase responses of rat and human bone marrow derived mesenchymal stem cells to 45S5 bioactive glass  

Microsoft Academic Search

Bioactive glass is used as both a bone filler and as a coating on implants, and has been advocated as a potential osteogenic scaffold for tissue engineering. Rat-derived mesenchymal stem cells (MSCs) show elevated levels of alkaline phosphatase activity when grown on 45S5 bioactive glass as compared to standard tissue culture plastic. Similarly, exposure to the dissolution products of 45S5

Gwendolen C. Reilly; Shula Radin; Andrew T. Chen; Paul Ducheyne

2007-01-01

59

Degradation, bioactivity, and osteogenic potential of composites made of PLGA and two different sol-gel bioactive glasses.  

PubMed

We have developed poly(L: -lactide-co-glycolide) (PLGA) based composites using sol-gel derived bioactive glasses (S-BG), previously described by our group, as composite components. Two different composite types were manufactured that contained either S2-high content silica S-BG, or A2-high content lime S-BG. The composites were evaluated in the form of sheets and 3D scaffolds. Sheets containing 12, 21, and 33 vol.% of each bioactive glass were characterized for mechanical properties, wettability, hydrolytic degradation, and surface bioactivity. Sheets containing A2 S-BG rapidly formed a hydroxyapatite surface layer after incubation in simulated body fluid. The incorporation of either S-BG increased the tensile strength and Young's modulus of the composites and tailored their degradation rates compared to starting compounds. Sheets and 3D scaffolds were evaluated for their ability to support growth of human bone marrow cells (BMC) and MG-63 cells, respectively. Cells were grown in non-differentiating, osteogenic or osteoclast-inducing conditions. Osteogenesis was induced with either recombinant human BMP-2 or dexamethasone, and osteoclast formation with M-CSF. BMC viability was lower at higher S-BG content, though specific ALP/cell was significantly higher on PLGA/A2-33 composites. Composites containing S2 S-BG enhanced calcification of extracellular matrix by BMC, whereas incorporation of A2 S-BG in the composites promoted osteoclast formation from BMC. MG-63 osteoblast-like cells seeded in porous scaffolds containing S2 maintained viability and secreted collagen and calcium throughout the scaffolds. Overall, the presented data show functional versatility of the composites studied and indicate their potential to design a wide variety of implant materials differing in physico-chemical properties and biological applications. We propose these sol-gel derived bioactive glass-PLGA composites may prove excellent potential orthopedic and dental biomaterials supporting bone formation and remodeling. PMID:21487840

Pamula, Elzbieta; Kokoszka, Justyna; Cholewa-Kowalska, Katarzyna; Laczka, Maria; Kantor, Lukasz; Niedzwiedzki, Lukasz; Reilly, Gwendolen C; Filipowska, Joanna; Madej, Wojciech; Kolodziejczyk, Malgorzata; Tylko, Grzegorz; Osyczka, Anna M

2011-04-13

60

Effect of bioactive borate glass microstructure on bone regeneration, angiogenesis, and hydroxyapatite conversion in a rat calvarial defect model.  

PubMed

Borate bioactive glasses are biocompatible and enhance new bone formation, but the effect of their microstructure on bone regeneration has received little attention. In this study scaffolds of borate bioactive glass (1393B3) with three different microstructures (trabecular, fibrous, and oriented) were compared for their capacity to regenerate bone in a rat calvarial defect model. 12weeks post-implantation the amount of new bone, mineralization, and blood vessel area in the scaffolds were evaluated using histomorphometric analysis and scanning electron microscopy. The amount of new bone formed was 33%, 23%, and 15%, respectively, of the total defect area for the trabecular, oriented, and fibrous microstructures. In comparison, the percent new bone formed in implants composed of silicate 45S5 bioactive glass particles (250-300?m) was 19%. Doping the borate glass with copper (0.4 wt.% CuO) had little effect on bone regeneration in the trabecular and oriented scaffolds, but significantly enhanced bone regeneration in the fibrous scaffolds (from 15 to 33%). The scaffolds were completely converted to hydroxyapatite within the 12week implantation. The amount of hydroxyapatite formed, 22%, 35%, and 48%, respectively, for the trabecular, oriented, and fibrous scaffolds, increased with increasing volume fraction of glass in the as-fabricated scaffold. Blood vessels infiltrated into all the scaffolds, but the trabecular scaffolds had a higher average blood vessel area compared with the oriented and fibrous scaffolds. While all three scaffold microstructures were effective in supporting bone regeneration, the trabecular scaffolds supported more bone formation and may be more promising in bone repair. PMID:23643606

Bi, Lianxiang; Rahaman, Mohamed N; Day, Delbert E; Brown, Zackary; Samujh, Christopher; Liu, Xin; Mohammadkhah, Ali; Dusevich, Vladimir; Eick, J David; Bonewald, Lynda F

2013-05-02

61

Preconditioned 70S30C bioactive glass foams promote osteogenesis in vivo.  

PubMed

Bioactive glass scaffolds (70S30C; 70% SiO2 and 30% CaO) produced by a sol-gel foaming process are thought to be suitable matrices for bone tissue regeneration. Previous in vitro data showed bone matrix production and active remodelling in the presence of osteogenic cells. Here we report their ability to act as scaffolds for in vivo bone regeneration in a rat tibial defect model, but only when preconditioned. Pretreatment methods (dry, pre-wetted or preconditioned without blood) for the 70S30C scaffolds were compared against commercial synthetic bone grafts (NovaBone® and Actifuse®). Poor bone ingrowth was found for both dry and wetted sol-gel foams, associated with rapid increase in pH within the scaffolds. Bone ingrowth was quantified through histology and novel micro-CT image analysis. The percentage bone ingrowth into dry, wetted and preconditioned 70S30C scaffolds at 11weeks were 10±1%, 21±2% and 39±4%, respectively. Only the preconditioned sample showed above 60% material-bone contact, which was similar to that in NovaBone and Actifuse. Unlike the commercial products, preconditioned 70S30C scaffolds degraded and were replaced with new bone. The results suggest that bioactive glass compositions should be redesigned if sol-gel scaffolds are to be used without preconditioning to avoid excess calcium release. PMID:23891811

Midha, Swati; Kim, Taek Bo; van den Bergh, Wouter; Lee, Peter D; Jones, Julian R; Mitchell, Christopher A

2013-07-25

62

Proangiogenic Potential of a Collagen\\/Bioactive Glass Substrate  

Microsoft Academic Search

Purpose  Previous attempts to stimulate angiogenesis have focused on the delivery of growth factors and cytokines, genes encoding for\\u000a specific angiogenic inductive proteins or transcription factors, or participating cells. While high concentrations of bioactive\\u000a glasses have exhibited osteogenic potential, recent studies have demonstrated that low concentrations of particular bioactive\\u000a glasses are angiogenic. We hypothesized that a well known bioactive glass (Bioglass®

Ann Leu; J. Kent Leach

2008-01-01

63

Surface functionalization of 3D glass-ceramic porous scaffolds for enhanced mineralization in vitro  

NASA Astrophysics Data System (ADS)

Bone reconstruction after tissue loosening due to traumatic, pathological or surgical causes is in increasing demand. 3D scaffolds are a widely studied solution for supporting new bone growth. Bioactive glass-ceramic porous materials can offer a three-dimensional structure that is able to chemically bond to bone. The ability to surface modify these devices by grafting biologically active molecules represents a challenge, with the aim of stimulating physiological bone regeneration with both inorganic and organic signals. In this research work glass ceramic scaffolds with very high mechanical properties and moderate bioactivity have been functionalized with the enzyme alkaline phosphatase (ALP). The material surface was activated in order to expose hydroxyl groups. The activated surface was further grafted with ALP both via silanization and also via direct grafting to the surface active hydroxyl groups.Enzymatic activity of grafted samples were measured by means of UV-vis spectroscopy before and after ultrasonic washing in TRIS-HCl buffer solution. In vitro inorganic bioactivity was investigated by soaking the scaffolds after the different steps of functionalization in a simulated body fluid (SBF). SEM observations allowed the monitoring of the scaffold morphology and surface chemical composition after soaking in SBF. The presence of ALP enhanced the in vitro inorganic bioactivity of the tested material.

Ferraris, Sara; Vitale-Brovarone, Chiara; Bretcanu, Oana; Cassinelli, Clara; Vernè, Enrica

2013-04-01

64

Mesoporous bioactive glasses: structure characteristics, drug/growth factor delivery and bone regeneration application  

PubMed Central

The impact of bone diseases and trauma in the whole world has increased significantly in the past decades. Bioactive glasses are regarded as an important bone regeneration material owing to their generally excellent osteoconductivity and osteostimulativity. A new class of bioactive glass, referred to as mesoporous bioglass (MBG), was developed 7 years ago, which possess a highly ordered mesoporous channel structure and a highly specific surface area. The study of MBG for drug/growth factor delivery and bone tissue engineering has grown significantly in the past several years. In this article, we review the recent advances of MBG materials, including the preparation of different forms of MBG, composition–structure relationship, efficient drug/growth factor delivery and bone tissue engineering application. By summarizing our recent research, the interaction of MBG scaffolds with bone-forming cells, the effect of drug/growth factor delivery on proliferation and differentiation of tissue cells and the in vivo osteogenesis of MBG scaffolds are highlighted. The advantages and limitations of MBG for drug delivery and bone tissue engineering have been compared with microsize bioactive glasses and nanosize bioactive glasses. The future perspective of MBG is discussed for bone regeneration application by combining drug delivery with bone tissue engineering and investigating the in vivo osteogenesis mechanism in large animal models.

Wu, Chengtie; Chang, Jiang

2012-01-01

65

Biomimetic and bioactive nanofibrous scaffolds from electrospun composite nanofibers  

PubMed Central

Electrospinning is an enabling technology that can architecturally (in terms of geometry, morphology or topography) and biochemically fabricate engineered cellular scaffolds that mimic the native extracellular matrix (ECM). This is especially important and forms one of the essential paradigms in the area of tissue engineering. While biomimesis of the physical dimensions of native ECM’s major constituents (eg, collagen) is no longer a fabrication-related challenge in tissue engineering research, conveying bioactivity to electrospun nanofibrous structures will determine the efficiency of utilizing electrospun nanofibers for regenerating biologically functional tissues. This can certainly be achieved through developing composite nanofibers. This article gives a brief overview on the current development and application status of employing electrospun composite nanofibers for constructing biomimetic and bioactive tissue scaffolds. Considering that composites consist of at least two material components and phases, this review details three different configurations of nanofibrous composite structures by using hybridizing basic binary material systems as example. These are components blended composite nanofiber, core-shell structured composite nanofiber, and nanofibrous mingled structure.

Zhang, YZ; Su, B; Venugopal, J; Ramakrishna, S; Lim, CT

2007-01-01

66

Submicron bioactive glass tubes for bone tissue engineering  

Microsoft Academic Search

Herein we describe a method to fabricate submicron bioactive glass tubes using sol–gel and coaxial electrospinning techniques for applications in bone tissue engineering. Heavy mineral oil and gel solution were delivered by two independent syringe pumps during the coaxial electrospinning process. Subsequently, submicron bioactive glass tubes were obtained by removal of poly(vinyl pyrrolidone) and heavy mineral oil via calcination at

Jingwei Xie; Eric R. Blough; Chi-Hwa Wang

67

Alkali-free bioactive glasses for bone tissue engineering: A preliminary investigation  

SciTech Connect

An alkali-free series of bioactive glasses has been designed and developed in the glass system CaO-MgO-SiO2-P2O5-CaF2 along diopside (CaMgSi2O6) – fluorapatite [Ca5(PO4)3F] – tricalcium phosphate (3CaO•P2O5) join. The silicate network in all the investigated glasses is predominantly coordinated in Q2 (Si) units while phosphorus tends to remain in orthophosphate (Q0) environment. The in vitro bioactivity analysis of glasses has been made by immersion of glass powders in simulated body fluid (SBF) while chemical degradation has been studied in Tris-HCl in accordance with ISO-10993-14. Some of the investigated glasses exhibit hydroxyapatite (HA) formation on their surface with in 1-12 h of their immersion in SBF solution. The sintering and crystallization kinetics of glasses has been investigated by differential thermal analysis (DTA) and hot-stage microscopy (HSM), respectively while the crystalline phase evolution in resultant glass-ceramics (GCs) has been studied in the temperature range of 800-900 oC using powder X-ray diffraction (XRD) and scanning electron microscope (SEM). The cell growth and osteogenic differentiation for glasses has been studied in vitro on sintered glass powder compacts using rat bone marrow mesenchymal stem cells. The as designed glasses are ideal candidates for their potential applications in bone tissue engineering in the form of bioactive glasses as well as glass/GC scaffolds.

Goel, Ashutosh; Kapoor, Saurabh; Rajagopal, Raghu R.; Pascual, Maria J.; Kim, Hae-Won; Ferreira, Jose M.

2011-08-25

68

Plasma-sprayed calcium phosphate particles with high bioactivity and their use in bioactive scaffolds.  

PubMed

Highly crystalline feedstock hydroxyapatite (HA) particles with irregular shapes were spheroidized by plasma spraying them onto the surface of ice blocks or into water. The spherical Ca-P particles thus produced contained various amounts of the amorphous phase which were controlled by the stand-off distance between the spray nozzle and the surface of ice blocks or waiter. The smooth surface morphology without cracks of spherical Ca-P particles indicated that there were very low thermal stresses in these particles. Plasma-sprayed Ca-P particles were highly bioactive due to their amorphous component and hence quickly induced the formation of bone-like apatite on their surfaces after they were immersed in an acellular simulated body fluid at 36.5 C. Bone-like apatite nucleated on dissolved surface (due to the amorphous phase) of individual Ca-P particles and grew to coalesce between neighboring Ca-P particles thus forming an integrated apatite plate. Bioactive and biodegradable composite scaffolds were produced by incorporating plasma-spray ed Ca-P particles into a degradable polymer. In vitro experiments showed that plasma-sprayed Ca-P particles enhanced the formation of bone-like apatite on the pore surface of Ca-P/PLLA composite scaffolds. PMID:12059011

Weng, Jie; Wang, Min; Chen, Jiyong

2002-07-01

69

Bioactivated collagen-based scaffolds embedding protein-releasing biodegradable microspheres: tuning of protein release kinetics.  

PubMed

In tissue engineering, the recapitulation of natural sequences of signaling molecules, such as growth factors, as occurring in the native extracellular matrix (ECM), is fundamental to support the stepwise process of tissue regeneration. Among the manifold of tissue engineering strategies, a promising one is based on the creation of the chrono-programmed presentation of different signaling proteins. This approach is based upon the integration of biodegradable microspheres, loaded with suitable protein molecules, within scaffolds made of collagen and, in case, hyaluronic acid, which are two of the fundamental ECM constituents. However, for the design of bioactivated gel-like scaffolds the determination of release kinetics must be performed directly within the tissue engineering template. In this work, biodegradable poly(lactic-co-glycolic)acid (PLGA) microspheres were produced by the multiple emulsion-solvent evaporation technique and loaded with rhodamine-labelled bovine serum albumin (BSA-Rhod), a fluorescent model protein. The microdevices were dispersed in collagen gels and collagen-hyaluronic acid (HA) semi-interpenetrating networks (semi-IPNs). BSA-Rhod release kinetics were studied directly on single microspheres through confocal laser scanning microscopy (CLSM). To thoroughly investigate the mechanisms governing protein release from PLGA microspheres in gels, BSA-Rhod diffusion in gels was determined by fluorescence correlation spectroscopy (FCS), and water transport through the microsphere bulk was determined by dynamic vapor sorption (DVS). Moreover, the decrease of PLGA molecular weight and glass transition temperature (T(g)) were determined by gel permeation chromatography (GPC) and differential scanning calorimetry (DSC), respectively. Results indicate that protein release kinetics and delivery onset strongly depend on the complex interplay between protein transport through the PLGA matrix and in the collagen-based release media, and water sequestration within the scaffolds, related to the scaffold hydrophilicity, which is dictated by HA content. The proper manipulation of all these features may thus allow the obtainment of a fine control over protein sequential delivery and release kinetics within tissue-engineering scaffolds. PMID:19449203

Biondi, Marco; Indolfi, Laura; Ungaro, Francesca; Quaglia, Fabiana; La Rotonda, Maria Immacolata; Netti, Paolo A

2009-05-18

70

The Preparation and Properties of Bioactive Composites Based on Modification Bioactive Glass and Poly(Lactide-Co-Glycolide)  

Microsoft Academic Search

PLGA\\/bioactive glass composites were prepared as promising bone-repairing materials. The bioactive glass was fabricated by Sol-gel method. Surface Modification was done to improve the phase compatibility between polymer and the inorganic phase. PLGA\\/bioactive glass composites were successfully prepared via solution dispersion method. Composites films with different content of bioactive glass were obtained. The mechanical properties of composites were characterized by

Jian Chen; Xin Fan; Zhongcheng Zhou; Jianpeng Zou; Jianming Ruan

2010-01-01

71

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

PubMed

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

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

2012-12-20

72

Antimicrobial Effect of Nanometric Bioactive Glass 45S5  

Microsoft Academic Search

Most recent advances in nanomaterials fabrication have given access to complex materials such as SiO2-Na2O-CaO-P2O5 bioactive glasses in the form of amorphous nanoparticles of 20-to 60-nm size. The clinically interesting antimicrobial properties of commercially available, micron-sized bioactive glass 45S5 have been attributed to the continuous liberation of alkaline species during application. Here, we tested the hypothesis that, based on its

T. Waltimo; T. J. Brunner; M. Vollenweider; W. J. Stark; M. Zehnder

2007-01-01

73

Bioactive porous scaffolds for tissue engineering applications: investigation on the degradation process by Raman spectroscopy and scanning electron microscopy.  

PubMed

Bioactive glasses in the Na2 O-K2 O-MgO-CaO-B2 O3 -P2 O5 -SiO2 system characterized by an unusually large working range were used for the production of fiber porous scaffolds. In vitro tests were carried out by immersing the scaffolds in simulated body fluid (SBF) solution; soaking time and glass composition effects on the degradation of the material are the principal subject of this investigation. Raman spectroscopy and scanning electron microscopy (SEM) were used as the main investigative methods. The study demonstrates the importance of the network modifiers and, in particular, of the amount of alkaline and al-kaline earths in the different stages of the material degradation and in the development of the hydroxyl-carbonate-apatite (HCA) layer. PMID:20799209

Moimas, L; De Rosa, G; Sergo, V; Schmid, C

74

Cytotoxicity assessment of modified bioactive glasses with MLO-A5 osteogenic cells in vitro.  

PubMed

The primary objective of this study was to evaluate in vitro responses of MLO-A5 osteogenic cells to two modifications of the bioactive glass 13-93. The modified glasses, which were designed for use as cell support scaffolds and contained added boron to form the glasses 13-93 B1 and 13-93 B3, were made to accelerate formation of a bioactive hydroxyapatite surface layer and possibly enhance tissue growth. Quantitative MTT cytotoxicity tests revealed no inhibition of growth of MLO-A5 cells incubated with 13-93 glass extracts up to 10 mg/ml, moderate inhibition of growth with 13-93 B1 glass extracts, and noticeable inhibition of growth with 13-93 B3 glass extracts. A morphology-based biocompatibility test was also performed and yielded qualitative assessments of the relative biocompatibilities of glass extracts that agree with those obtained by the quantitative MTT test. However, as a proof of concept experiment, when MLO-A5 cells were seeded onto 13-93 B3 scaffolds in a dynamic in vitro environment, cell proliferation occurred as evidenced by qualitative and quantitative MTT labeling of scaffolds. Together these results demonstrate the in vitro toxicity of released borate ion in static experiments; however borate ion release can be mitigated in a dynamic environment similar to the human body where microvasculature is present. Here we argue that despite toxicity in static environments, boron-containing 13-93 compositions may warrant further study for use in tissue engineering applications. PMID:23392968

Modglin, Vernon C; Brown, Roger F; Jung, Steven B; Day, Delbert E

2013-02-08

75

Bioactive glass sol-gel foam scaffolds: Evolution of nanoporosity during processing and in situ monitoring of apatite layer formation using small- and wide-angle X-ray scattering.  

PubMed

Recent work has highlighted the potential of sol-gel-derived calcium silicate glasses for the regeneration or replacement of damaged bone tissue. The work presented herein provides new insight into the processing of bioactive calcia-silica sol-gel foams, and the reaction mechanisms associated with them when immersed in vitro in a simulated body fluid (SBF). Small-angle X-ray scattering and wide-angle X-ray scattering (diffraction) have been used to study the stabilization of these foams via heat treatment, with analogous in situ time-resolved data being gathered for a foam immersed in SBF. During thermal processing, pore sizes have been identified in the range of 16.5-62.0 nm and are only present once foams have been heated to 400 degrees C and above. Calcium nitrate crystallites were present until foams were heated to 600 degrees C; the crystallite size varied from 75 to 145 nm and increased in size with heat treatment up to 300 degrees C, then decreased in size down to 95 nm at 400 degrees C. The in situ time-resolved data show that the average pore diameter decreases as a function of immersion time in SBF, as calcium phosphates grow on the glass surfaces. Over the same time, Bragg peaks indicative of tricalcium phosphate were evident after only 1-h immersion time, and later, hydroxycarbonate apatite was also seen. The hydroxycarbonate apatite appears to have preferred orientation in the (h,k,0) direction. PMID:18767060

FitzGerald, V; Martin, R A; Jones, J R; Qiu, D; Wetherall, K M; Moss, R M; Newport, R J

2009-10-01

76

A composite fibrin-based scaffold for controlled delivery of bioactive pro-angiogenetic growth factors  

Microsoft Academic Search

The aim of this study was to fabricate and characterize in vitro a novel composite scaffold that, combining good mechanical properties with a controlled and sustained release of bioactive pro-angiogenetic growth factors, should be useful for angiogenesis induction in organs\\/tissues in which is also necessary to give resistance and mechanical strength. Composite scaffolds, constituted by a synthetic biocompatible material, a

Enrica Briganti; Dario Spiller; Chiara Mirtelli; Silvia Kull; Claudio Counoupas; Paola Losi; Sonia Senesi; Rossella Di Stefano; Giorgio Soldani

2010-01-01

77

Self-reinforced composites of bioabsorbable polymer and bioactive glass with different bioactive glass contents. Part I: Initial mechanical properties and bioactivity.  

PubMed

Spherical bioactive glass 13-93 particles, with a particle size distribution of 50-125 microm, were combined with bioabsorbable poly-L,DL-lactide 70/30 using twin-screw extrusion. The composite rods containing 0, 20, 30, 40 and 50 wt% of bioactive glass were further self-reinforced by drawing to a diameter of approximately 3 mm. The bioactive glass spheres were well dispersed and the open pores were formed on the composite surface during drawing. The initial mechanical properties were studied. The addition of bioactive glass reduced the bending strength, bending modulus, shear strength, compression strength and torsion strength of poly-L,DL-lactide. However, the strain at maximum bending load increased in self-reinforced composites. Initially brittle composites became ductile in self-reinforcing. The bioactivity was studied in phosphate buffered saline for up to 12 days. The formation of calcium phosphate precipitation was followed using scanning electron microscopy and energy dispersive X-ray analysis. Results showed that the bioactive glass addition affected the initial mechanical properties and bioactivity of the composites. It was concluded that the optimal bioactive glass content depends on the applications of the composites. PMID:16701800

Niemelä, T; Niiranen, H; Kellomäki, M; Törmälä, P

2004-12-25

78

Foam-like scaffolds for bone tissue engineering based on a novel couple of silicate-phosphate specular glasses: synthesis and properties.  

PubMed

Glass-ceramic scaffolds mimicking the structure of cancellous bone were produced via sponge replication technique by using a polyurethane foam as template and glass powder below 30 lm as inorganic phase. Specifically, a SiO?-based glass of complex composition and its corresponding P?O?-based "specular" glass were used as materials for scaffolding. The polymeric sponge was thermally removed and the glass powders were sintered to obtain a replica of the template structure. The scaffolds were investigated and compared from a structural, morphological and mechanical viewpoint by assessing their crystalline phases, volumetric shrinkage, pores content and interconnection, mechanical strength. In addition, the scaffolds were soaked in acellular simulated body fluid to investigate their in vitro behaviour. The produced scaffolds have a great potential for bone reconstructive surgery because their features, such as shape, strength, bioactivity and bioresorption, can be easily tailored according to the end use. PMID:19475339

Vitale-Brovarone, Chiara; Baino, Francesco; Bretcanu, Oana; Verne, Enrica

2009-05-28

79

Bioactive Electrospun Scaffolds Delivering Growth Factors and Genes for Tissue Engineering Applications  

Microsoft Academic Search

A biomaterial scaffold is one of the key factors for successful tissue engineering. In recent years, an increasing tendency\\u000a has been observed toward the combination of scaffolds and biomolecules, e.g. growth factors and therapeutic genes, to achieve\\u000a bioactive scaffolds, which not only provide physical support but also express biological signals to modulate tissue regeneration.\\u000a Huge efforts have been made on

Wei Ji; Yan Sun; Fang Yang; Jeroen J. J. P. van den Beucken; Mingwen Fan; Zhi Chen; John A. Jansen

2011-01-01

80

Analysis of bioactive fluoride-containing calcium aluminosilicate glasses  

Microsoft Academic Search

Different decomposition methods in aqueous solutions were evaluated on their accuracy and reproducibility for the quantitative determination of the constituents of bioactive fluoride-containing glasses used in dental glass ionomer cements. The concentrations of metals can be determined rapidly and accurately by atomic absorption spectrophotometry after degrading the sample in hydrochloric or hydrofluoric acid. The latter degradation method is also suited

E. A. P De Maeyer; R. M. H Verbeeck

1998-01-01

81

Bioactive glass fiber/polymeric composites bond to bone tissue.  

PubMed

Bioactive glass fibers were investigated for use as a fixation vehicle between a low modulus, polymeric composite and bone tissue. In an initial pilot study, bioactive glass fiber/polysulfone composites and all-polysulfone control rods were implanted into the rabbit tibia; the study was subsequently expanded with implantation into the rabbit femur. Bone tissue exhibited direct contact with the glass fibers and adjacent polymer matrix and displayed a mechanical bond between the composite and bone tissue after six weeks implantation. Interfacial bond strengths after six weeks implantation averaged 12.4 MPa, significantly higher than those of the all-polymer controls. Failure sites for the composite at six weeks generally occurred in the bone tissue or composite, whereas the failure site for the polymer implants occurred exclusively at the implant/tissue interface. The bioactive glass fiber/polysulfone composite achieved fixation to bone tissue through a triple mechanism: a bond to the bioactive glass fiber, mechanical interlocking between the tissue and glass fibers, and close apposition and possible chemical bond between the portions of the polymer and bone tissue. This last mechanism resulted from an overspill of bioactivity reactions from the fibers onto the surface of the surrounding polymer which we call the "halo" effect. PMID:9429107

Marcolongo, M; Ducheyne, P; Garino, J; Schepers, E

1998-01-01

82

Broad-Spectrum Bactericidal Activity of Ag2O-Doped Bioactive Glass  

PubMed Central

Bioactive glass has found extensive application as an orthopedic and dental graft material and most recently also as a tissue engineering scaffold. Here we report an initial investigation of the in vitro antibacterial properties of AgBG, a novel bioactive glass composition doped with Ag2O. The bacteriostatic and bactericidal properties of this new material and of two other bioactive glass compositions, 45S5 Bioglass and BG, have been studied by using Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus as test microorganisms. Concentrations of AgBG in the range of 0.05 to 0.20 mg of AgBG per ml of culture medium were found to inhibit the growth of these bacteria. Not only was AgBG bacteriostatic, but it also elicited a rapid bactericidal action. A complete bactericidal effect was elicited within the first hours of incubation at AgBG concentrations of 10 mg ml?1. 45S5 Bioglass and BG had no effect on bacterial growth or viability. The antibacterial action of AgBG is attributed exclusively to the leaching of Ag+ ions from the glass matrix. Analytical measurements rule out any contribution to AgBG-mediated bacterial killing by changes in pH or ionic strength or the dissolution of other ionic species from the biomaterials. Our observations of the dissolution profiles of Ag+ from AgBG in the presence and absence of bacteria are consistent with silver accumulation by the bacteria.

Bellantone, Maria; Williams, Huw D.; Hench, Larry L.

2002-01-01

83

Effect of nitrogen and fluorine on mechanical properties and bioactivity in two series of bioactive glasses.  

PubMed

Bioactive glasses are able to bond to bone through formation of carbonated hydroxyapatite in body fluids, and fluoride-releasing bioactive glasses are of interest for both orthopaedic and, in particular, dental applications for caries inhibition. However, because of their poor strength their use is restricted to non-load-bearing applications. In order to increase their mechanical properties, doping with nitrogen has been performed on two series of bioactive glasses: series (I) was a "bioglass" composition (without P2O5) within the quaternary system SiO2-Na2O-CaO-Si3N4 and series (II) was a simple substitution of CaF2 for CaO in series (I) glasses keeping the Na:Ca ratio constant. The objective of this work was to evaluate the effect of the variation in nitrogen and fluorine content on the properties of these glasses. The density, glass transition temperature, hardness and elastic modulus all increased linearly with nitrogen content which indicates that the incorporation of nitrogen stiffens the glass network because N is mainly in 3-fold coordination with Si atoms. Fluorine addition significantly decreases the thermal property values but the mechanical properties of these glasses remain unchanged with fluorine. The combination of both nitrogen and fluorine in oxyfluoronitride glasses gives better mechanical properties at much lower melting temperatures since fluorine reduces the melting point, allows higher solubility of nitrogen and does not affect the higher mechanical properties arising from incorporation of nitrogen. The characterization of these N and F substituted bioactive glasses using (29)Si MAS NMR has shown that the increase in rigidity of the glass network can be explained by the formation of SiO3N, SiO2N2 tetrahedra and Q(4) units with extra bridging anions at the expense of Q(3) units. Bioactivity of the glasses was investigated in vitro by examining apatite formation on the surface of glasses treated in acellular simulated body fluid (SBF) with ion concentrations similar to those in human blood plasma. Formation of a bioactive apatite layer on the samples treated in SBF was confirmed by grazing incidence X-ray diffraction and scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDS). The crystallinity of this layer decreases with increasing N content suggesting that N may decrease bioactivity slightly. PMID:23676624

Bachar, Ahmed; Mercier, Cyrille; Tricoteaux, Arnaud; Hampshire, Stuart; Leriche, Anne; Follet, Claudine

2013-04-10

84

The cementogenic differentiation of periodontal ligament cells via the activation of Wnt/?-catenin signalling pathway by Li+ ions released from bioactive scaffolds.  

PubMed

Lithium (Li) has been widely used as a long-term mood stabilizer in the treatment of bipolar and depressive disorders. Li(+) ions are thought to enhance the remyelination of peripheral nerves and also stimulate the proliferation of neural progenitor cells and retinoblastoma cells via activation of the Wnt/?-catenin signalling pathway. Until now there have been no studies reporting the biological effects of released Li(+) in bioactive scaffolds on cemetogenesis in periodontal tissue engineering applications. In this study, we incorporated parts of Li(+) ions into the mesoporous bioactive glass (MBG) scaffolds and showed that this approach yielded scaffolds with a favourable composition, microstructure and mesopore properties for cell attachment, proliferation, and cementogenic differentiation of human periodontal ligament-derived cells (hPDLCs). We went on to investigate the biological effects of Li(+) ions themselves on cell proliferation and cementogenic differentiation. The results showed that 5% Li(+) ions incorporated into MBG scaffolds enhanced the proliferation and cementogenic differentiation of hPDLCs on scaffolds, most likely via activation of Wnt/?-catenin signalling pathway. Further study demonstrated that Li(+) ions by themselves significantly enhanced the proliferation, differentiation and cementogenic gene expression of PDLCs. Our results indicate that incorporation of Li(+) ions into bioactive scaffolds is a viable means of enhancing the Wnt canonical signalling pathway to stimulate cementogenic differentiation of PDLCs. PMID:22732362

Han, Pingping; Wu, Chengtie; Chang, Jiang; Xiao, Yin

2012-06-23

85

Synthesis and electrospinning of ?-polycaprolactone-bioactive glass hybrid biomaterials via a sol-gel process.  

PubMed

Strategies of bone tissue engineering and regeneration rely on bioactive scaffolds to mimic the natural extracellular matrix (ECM) as templates onto which cells attach, multiply, migrate, and function. For this purpose, hybrid biomaterials based on smart combinations of biodegradable polymers and bioactive glasses (BGs) are of particular interest, since they exhibit tailored physical, biological, and mechanical properties, as well as predictable degradation behavior. In this study, hybrid biomaterials with different organic-inorganic ratios were successfully synthesized via a sol-gel process. Poly(?-caprolactone) (PCL) and tertiary bioactive glass (BG) with a glass composition of 70 mol % SiO(2), 26 mol % CaO, and 4 mol % of P(2)O(5) were used as the polymer and inorganic phases, respectively. The polymer chains were successfully introduced into the inorganic sol while the networks were formed. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analyses (TGA), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) were used to investigate the presence of different chemical groups, structural crystallinity, thermal property, elemental composition, and homogeneity of the synthesized hybrid biomaterials. Identification of chemical groups and the presence of molecular interaction by hydrogen bonding between the organic and inorganic phases was confirmed by FTIR. The XRD patterns showed that all PCL/BG hybrids (up to 60% polymer content) were amorphous. The TGA study revealed that the PCL/BG hybrid biomaterials were thermally stable, and good agreement was observed between the experimental and theoretical organic-inorganic ratios. The SEM/EDX results also revealed a homogeneous elemental distribution and demonstrated the successful incorporation of all the elements in the hybrid system. Finally, these synthesized hybrid biomaterials were successfully electrospun into 3D scaffolds. The resultant fibers have potential use as scaffolds for bone regeneration. PMID:21050002

Allo, Bedilu A; Rizkalla, Amin S; Mequanint, Kibret

2010-11-04

86

Thermal analysis and in vitro bioactivity of bioactive glass-alumina composites  

SciTech Connect

Bioactive glass-alumina composite (BA) pellets were fabricated in the range 95/5-60/40 wt.% respectively and were heat-treated under a specific thermal treatment up to 950 {sup o}C. Control (unheated) and heat-treated pellets were immersed in Simulated Body Fluid (SBF) for bioactivity testing. All pellets before and after immersion in SBF were studied by Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM-EDS) and X-ray Diffraction (XRD) analysis. All composite pellets presented bioactive response. On the surface of the heat-treated pellets the development of a rich biological hydroxyapatite (HAp) layer was delayed for one day, compared to the respective control pellets. Independent of the proportion of the two components, all composites of each group (control and heat-treated) presented the same bioactive response as a function of immersion time in SBF. It was found that by the applied methodology, Al{sub 2}O{sub 3} can be successfully applied in bioactive glass composites without obstructing their bioactive response. - Research Highlights: {yields} Isostatically pressed glass-alumina composites presented apatite-forming ability. {yields} The interaction with SBF resulted in an aluminium phosphate phase formation. {yields} The formation of an aluminium phosphate phase enhanced the in vitro apatite growth.

Chatzistavrou, Xanthippi, E-mail: x.chatzistavrou@imperial.ac.uk [Solid State Physics Section, Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Kantiranis, Nikolaos, E-mail: kantira@geo.auth.gr [School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Kontonasaki, Eleana, E-mail: kont@dent.auth.gr [School of Dentistry, Department of Fixed Prosthesis and Implant Prosthodontics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Chrissafis, Konstantinos, E-mail: hrisafis@physics.auth.gr [Solid State Physics Section, Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Papadopoulou, Labrini, E-mail: lambrini@geo.auth.gr [School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Koidis, Petros, E-mail: pkoidis@dent.auth.gr [School of Dentistry, Department of Fixed Prosthesis and Implant Prosthodontics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Boccaccini, Aldo R., E-mail: a.boccaccini@imperial.ac.uk [Department of Materials, Faculty of Engineering, Imperial College, SW7 2AZ London (United Kingdom); Paraskevopoulos, Konstantinos M., E-mail: kpar@auth.gr [Solid State Physics Section, Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

2011-01-15

87

Incorporation of bioactive glass in calcium phosphate cement: An evaluation.  

PubMed

Bioactive glasses (BGs) are known for their unique ability to bond to living bone. Consequently, the incorporation of BGs into calcium phosphate cement (CPC) was hypothesized to be a feasible approach to improve the biological performance of CPC. Previously, it has been demonstrated that BGs can successfully be introduced into CPC, with or without poly(d,l-lactic-co-glycolic) acid (PLGA) microparticles. Although an in vitro physicochemical study on the introduction of BG into CPC was encouraging, the biocompatibility and in vivo bone response to these formulations are still unknown. Therefore, the present study aimed to evaluate the in vivo performance of BG supplemented CPC, either pure or supplemented with PLGA microparticles, via both ectopic and orthotopic implantation models in rats. Pre-set scaffolds in four different formulations (1: CPC; 2: CPC/BG; 3: CPC/PLGA; and 4: CPC/PLGA/BG) were implanted subcutaneously and into femoral condyle defects of rats for 2 and 6 weeks. Upon ectopic implantation, incorporation of BG into CPC improved the soft tissue response by improving capsule and interface quality. Additionally, the incorporation of BG into CPC and CPC/PLGA showed 1.8- and 4.7-fold higher degradation and 2.2- and 1.3-fold higher bone formation in a femoral condyle defect in rats compared to pure CPC and CPC/PLGA, respectively. Consequently, these results highlight the potential of BG to be used as an additive to CPC to improve the biological performance for bone regeneration applications. Nevertheless, further confirmation is necessary regarding long-term in vivo studies, which also have to be performed under compromised wound-healing conditions. PMID:23159565

Renno, A C M; van de Watering, F C J; Nejadnik, M R; Crovace, M C; Zanotto, E D; Wolke, J G C; Jansen, J A; van den Beucken, J J J P

2012-11-14

88

Preparation and bioactive properties of novel bone-repair bionanocomposites based on hydroxyapatite and bioactive glass nanoparticles.  

PubMed

Bionanocomposites based on ceramic nanoparticles and a biodegradable porous matrix represent a promising strategy for bone repair applications. The preparation and bioactive properties of bionanocomposites based on hydroxyapatite (nHA) and bioactive glass (nBG) nanoparticles were presented. nHA and nBG were synthesized with nanometric particle size using sol-gel/precipitation methods. Composite scaffolds were prepared by incorporating nHA and nBG into a porous alginate (ALG) matrix at different particle loads. The ability of the bionanocomposites to induce the crystallization of the apatite phase from simulated body fluid (SBF) was systematically evaluated using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray analysis, and Fourier transform infrared spectroscopy. Both nHA/ALG and nBG/ALG composites were shown to notably accelerate the process of crystallization and growth of the apatite phase on the scaffold surfaces. For short immersion times in SBF, nBG (25%)-based nanocomposites induced a higher degree of apatite crystallization than nHA (25%)-based nanocomposites, probably due to the more reactive nature of the BG particles. Through a reinforcement effect, the nanoparticles also improve the mechanical properties and stability in SBF of the polymer scaffold matrix. In addition, in vitro biocompatibility tests demonstrated that osteoblast cells are viable and adhere well on the surface of the bionanocomposites. These results indicate that nHA- and nBG-based bionanocomposites present potential properties for bone repair applications, particularly oriented to accelerate the bone mineralization process. PMID:22707209

Valenzuela, Francisco; Covarrubias, Cristian; Martínez, Constanza; Smith, Patricio; Díaz-Dosque, Mario; Yazdani-Pedram, Mehrdad

2012-06-15

89

Tissue response to bioactive glass and autogenous bone in the rabbit spine  

Microsoft Academic Search

Bioactive glass S53P4 and autogenous bone were used as bone graft materials in an experimental rabbit model for spinal fusion.\\u000a The study focused on differences in bone formation using bioactive glass and autogenous bone as bone graft materials. Bioactive\\u000a glass, a mixture of bioactive glass and autogenous bone or autogenous bone was implanted for 4 and 12 weeks at the

N. C. Lindfors; A. J. Aho

2000-01-01

90

A review of glass-ionomers: From conventional glass-ionomer to bioactive glass-ionomer  

PubMed Central

Materials used in the body, especially the materials used in various oral cavity regions should be stable and passive without any interactions with the body tissues or fluids. Dental amalgam, composite resins and dental cements are the materials of choice with such properties. The first attempts to produce active materials, which could interact with the human body tissues and fluids were prompted by the concept that fluoride-releasing materials exert useful effects in the body. The concept of using the “smart” materials in dentistry has attracted a lot of attention in recent years. Conventional glass-ionomer (GI) cements have a large number of applications in dentistry. They are biocompatible with the dental pulp to some extent. GI is predominantly used as cements in dentistry; however, they have some disadvantages, the most important of which is lack of adequate strength and toughness. In an attempt to improve the mechanical properties of the conventional GI, resin-modified glass-ionomers have been marketed, with hydrophilic monomers, such as hydroxyethyl methacrylated (HEMA). Some recent studies have evaluated GI with bioactive glass in its structure to validate the claims that such a combination will improve tooth bioactivity, regeneration capacity and restoration. There is ever-increasing interest in the application of bioactive materials in the dental field in an attempt to remineralize affected dentin. The aim of this review article is to evaluate these materials and their characteristics and applications.

Khoroushi, Maryam; Keshani, Fateme

2013-01-01

91

Bioactivity of tape cast and sintered bioactive glass-ceramic in simulated body fluid.  

PubMed

A common ceramic processing technique, tape casting, was used to produce thin, flexible sheets of bioactive glass (Bioglass 45S5) particulate in an organic matrix. Tape casting offers the possibility of producing three-dimensional shapes, as the final material is built up layer by layer. Bioactive glass tapes were sintered together to form small discs for in vitro bioactivity testing in simulated body fluid (SBF). Four different sintering schedules were investigated: 800, 900, and 1000 degrees C for 3 h; and 1000 degrees C for 6 h. Each schedule produced a crystalline material of major phase Na2Ca2Si3O9. Tape cast and sintered bioactive glass-ceramic processed at 1000 degrees C formed crystalline hydroxyapatite layers after 20-24 h in SBF as indicated by Fourier transform infrared spectroscopy, Scanning electron microscopy, and EDS data. FTIR revealed that the greatest amount of hydroxyapatite formation after 2 h was observed for samples sintered at 900 degrees C. The differences in bioactive response were likely caused by the variation in the extent of sintering and, consequently, the amount of surface area available for reaction with SBF. PMID:12033609

Clupper, Daniel C; Mecholsky, John J; LaTorre, Guy P; Greenspan, David C

2002-06-01

92

Investigation of the bioactivity and biocompatibility of different glass interfaces with hydroxyapatite, fluorohydroxyapatite and 58S bioactive glass.  

PubMed

The current review investigates the bioactivity of different glass interfaces created on thin glass cover slips as substrates. The interfaces studied are plain glass, functionalized glass using 0.5 M and 5 M of sodium hydroxide (NaOH) for 24 hrs, and glass coated with bioactive 58S Bioglass (58S). A biomimetic method, involving the exposure of the three interfaces to 1.5 times simulated body fluid (SBF) tests the bioactivity of the interfaces via creation of layer of Hydroxyapatite (HA). Fluorinated SBF will precipitate fluorine doped HA (FHA) on a bioactive interface. Higher concentration of 1.5 times of SBF used in this study intended to accelerate the formation of HA and FHA layer over the substrate. HA and FHA is found to be precipitated on the thinly coated 58S. This paper, study also the thin film coatings of three forms of bioceramics - bioactive 58S, HA and FHA. The study, also proposes to draw a relation between the morphology of HA particles with duration of exposure to SBF, the effects of fluorine on the morphology and the cell interaction with bioactive 58S, HA and FHA interfaces using pre-differentiated osteoblastic MC3T3 cells. The analysis of cells in this study is confined to three parameters that include the attachment, proliferation and viability of cells. Tests employed for the analysis of the thin film coating of HA and FHA is restricted to qualitative X-Ray Diffraction and quantitative Field Emission Scanning Electron Microscope. Other mechanical tests such as shear test are not used to test the mechanical properties of this thin layer, due to the fact that the thin film is too thin for such analysis. PMID:18607070

Han, Yuling Jamie; Loo, Say Chye Joachim; Lee, Joel; Ma, Jan

2007-01-01

93

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

PubMed

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

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

94

Silver-containing mesoporous bioactive glass with improved antibacterial properties.  

PubMed

The aim of the present work is the study of the bacteriostatic/bactericidal effect of a silver-containing mesoporous bioactive glass obtained by evaporation-induced self-assembly and successive thermal stabilization. Samples of the manufactured mesophase were characterized by means of transmission electron microscopy and N2 adsorption/desorption at 77 K, revealing structural and textural properties similar to SBA-15 mesoporous silica. Glass samples used for bioactivity experiments were put in contact with a standardized, commercially available cell culture medium instead of lab-produced simulated body fluid, and were then characterized by means of X-ray diffraction, field emission scanning electron microscopy and Fourier transform infrared spectroscopy. All these analyses confirmed the development of a hydroxyl carbonate apatite layer on glass particles. Moreover, the investigated mesostructure showed a very good antibacterial effect against S. aureus strain, with a strong evidence of bactericidal activity already registered at 0.5 mg/mL of glass concentration. A hypothesis about the mechanism by which Ag affects the bacterial viability, based on the intermediate formation of crystalline AgCl, was also taken into account. With respect to what already reported in the literature, these findings claim a deeper insight into the possible use of silver-containing bioactive glasses as multifunctional ceramic coatings for orthopedic devices. PMID:23712538

Gargiulo, Nicola; Cusano, Angela Maria; Causa, Filippo; Caputo, Domenico; Netti, Paolo Antonio

2013-05-28

95

Bioactive calcium pyrophosphate glasses and glass-ceramics.  

PubMed

Calcium phosphate glass-based materials in the pyrophosphate region are briefly reviewed. Calcium pyrophosphate glasses can be prepared by including a small amount of TiO(2) (glasses in simulated body fluid. By heating powder-compacts of the glasses, they are crystallized and subsequently are sintered, resulting in fabrication of high-strength glass-ceramics with machinability; they are easier to be machined using conventional tools in comparison with conventional calcium phosphate ceramics. beta-Ca(2)P(2)O(7) crystal formed in the glass-ceramics plays an important role in the machinability. Their apatite-forming ability in simulated body fluid is drastically enhanced after autoclaving in distilled water. The glass-ceramics can be easily coated on a new beta-type titanium alloy using a conventional glazing technique. PMID:16701780

Kasuga, Toshihiro

2005-01-01

96

A hierarchically graded bioactive scaffold bonded to titanium substrates for attachment to bone.  

PubMed

In this paper we report a Ti-based, hierarchical porous scaffold anchored to Ti substrates, prepared by synthesizing hydroxyapatite--calcium carbonate-Ti three--layer spheres and combining a modified plasma spraying process and an anodic oxidation treatment. The hierarchical porous scaffolds were composed of 100-350 ?m interconnecting macropores, 0.2-90 ?m pores and ~100 nm nanopores with >70% porosity. At the same time, the scaffolds also had the graded structures constructed by bioactive TiO(x) in surface transforming to metallurgy-bondable Ti in bottom. Mechanical property tests demonstrated that the porous scaffolds had similar Young's modulus with natural bone and strong bonding strength with the Ti substrates. The simulate body fluid immersion showed that bone-like apatite layer could form rapidly at scaffold surface. The in vitro cell incubation demonstrated that the porous scaffolds had good cellular compatibility and could correctly regulate cascade gene expression of primary osteoblasts. The intramuscular implantations indicated the porous scaffolds had high osteoinductivity and the bone implantations demonstrated that the scaffolds could facilitate new bone growth and have strong bonding strength with surrounding bone. PMID:21764439

Fu, Qingshan; Hong, Youliang; Liu, Xiaoguang; Fan, Hongsong; Zhang, Xingdong

2011-07-18

97

Imaging physicochemical reactions occurring at the pore surface in binary bioactive glass foams by micro ion beam analysis.  

PubMed

In this work, the physicochemical reactions occurring at the surface of bioactive sol-gel derived 3D glass scaffolds via a complete PIXE characterization were studied. 3D glass foams in the SiO(2)-CaO system were prepared by sol-gel route. Samples of glass scaffolds were soaked in biological fluids for periods up to 2 days. The surface changes were characterized using particle induced X-ray emission (PIXE) associated to Rutherford backscattering spectroscopy (RBS), which are efficient methods to perform quantitative chemical maps. Elemental maps of major and trace elements at the glass/biological fluids interface were obtained at the micrometer scale for every interaction time. Results revealed interconnected macropores and physicochemical reactions occurring at the surface of pores. The micro-PIXE-RBS characterization of the pores/biological fluids interface shows the glass dissolution and the rapid formation of a Ca rich layer with the presence of phosphorus that came from biological fluids. After 2 days, a calcium phosphate-rich layer containing magnesium is formed at the surface of the glass scaffolds. We demonstrate that quantities of phosphorus provided only by the biological medium have a significant impact on the development and the formation of the phosphocalcic layer. PMID:20527821

Jallot, E; Lao, J; John, L; Soulié, J; Moretto, Ph; Nedelec, J M

2010-06-01

98

Differential alkaline phosphatase responses of rat and human bone marrow derived mesenchymal stem cells to 45S5 bioactive glass  

PubMed Central

Bioactive glass is used as both a bone filler and as a coating on implants, and has been advocated as a potential osteogenic scaffold for tissue engineering. Rat derived mesenchymal stem cells (MSCs) show elevated levels of levels of alkaline phosphatase activity when grown on 45S5 bioactive glass as compared to standard tissue culture plastic. Similarly, exposure to the dissolution products of 45S5 elevates alkaline phosphatase activity and other osteogenic markers in these cells. We investigated whether human MSCs grown under the same laboratory conditions as rat MSCs would exhibit similar responses. In general, human MSCs produce markedly less alkaline phosphatase activity than rat MSCs, regardless of cell culture conditions, and do not respond to the growth factor BMP-2 in the same way as rat MSCs. In our experiments there was no difference in alkaline phosphatase activity between human MSCs grown on 45S5 bioactive glass or tissue culture plastic, in samples from five different orthopaedic patients, regardless of culture media composition. Neither was there any consistent effect of 45S5 dissolution products on human MSCs from three different donors. These results suggest that the positive effects of bioactive glass on bone growth in human patients are not mediated by accelerated differentiation of mesenchymal stem cells.

Reilly, Gwendolen C.; Radin, Shula; Chen, Andrew T.; Ducheyne, Paul

2009-01-01

99

Bioactive glass-polymer materials for controlled release of ibuprofen  

Microsoft Academic Search

The ibuprofen (IB) release from samples composed by SiO2–CaO–P2O5 bioactive glass, poly-L-lactic acid (PLA), and polymethylmethacrylate (PMMA) has been studied. Data showed a fast anti-inflammatory drug release during the first 8h when these polyphasic materials are soaked in simulated body fluid (SBF). The analysis of the samples before and after different soaking periods in SBF demonstrates the growth of an

S. Ladrón de Guevara-Fernández; C. V. Ragel; M. Vallet-Reg??

2003-01-01

100

Repair of orbital floor fractures with bioactive glass implants  

Microsoft Academic Search

Purpose: The ideal management of orbital floor fractures has been highly controversial. Many implants, both autogenous and alloplastic, have been used to span the defects. This study evaluated the use of bioactive glass implants (BAG-implant, S53P4; Abmin Technologies Ltd, Turku, Finland) for the repair of orbital floor defects caused by blunt facial trauma. Patients and Methods: This retrospective review of

Kalle Aitasalo; Ilpo Kinnunen; Jarkko Palmgren; Matti Varpula

2001-01-01

101

Crystallization kinetics of tape cast bioactive glass 45S5  

Microsoft Academic Search

The crystallization kinetics of tape cast bioactive glass 45S5 was studied using non-isothermal methods. XRD confirmed that Na2Ca2Si3O9 was formed during heating up to 1000 °C. The modified Kissinger equation was used to determine that the activation energy for crystallization was 350 kJ\\/mol. The Avrami exponent, n, was determined to be 0.96 (Ozawa method) and 0.94 (Augis–Bennett method). Such results

D. C. Clupper; L. L. Hench

2003-01-01

102

Processing, properties, and in vitro bioactivity of polysulfone-bioactive glass composites.  

PubMed

The mismatch between the mechanical properties of bioceramics and natural tissue has restricted in several cases a wider application of ceramics in medical and dental fields. To overcome this problem, polymer matrix composites can be designed to combine bioactive properties of some bioceramics with the superior mechanical properties of some engineering plastics. In this work, polymer particulate composites composed of a high mechanical-property polymer and bioactive glass particles were produced and both the in vitro bioactivity and properties of the system were investigated. Composites with different volume fraction and particle size were prepared. In vitro tests showed that hydroxy-carbonate-apatite can be deposited on the surface of a composite as early as 20 h in a simulated body fluid. Ionic evolution from a composite with 40% volume fraction of particles was demonstrated to be similar to bulk bioactive glasses. The mechanical properties of some of the obtained composites had values comparable with the ones reported for bone. Moreover, a physical model based on dynamical mechanical tests showed evidences that the interface of the composite was aiding in the stress transfer process. PMID:17031819

Oréfice, Rodrigo; Clark, Arthur; West, Jon; Brennan, Anthony; Hench, Larry

2007-03-01

103

Sintered porous DP-bioactive glass and hydroxyapatite as bone substitute.  

PubMed

There is extensive experimental and surgical experience with the use of bone tissue to fill defects in the skeleton, to bridge non-union sites, and to pack defects in bone created from cyst curettage. DP-bioactive glass with a chemical composition of Na2O 8.4%, SiO2 39.6%, P2O5 12% and CaO 40% has been reported as an alternative bone substitute of high mechanical strength, good biocompatibility. and which has a tight bond with living tissue. The bonding layer between DP-bioactive glass and bone tissue was considered to be formed by dissolution of calcium and phosphate ions from the DP-bioactive glass into the surrounding body fluids. The biological hydroxyapatite was suspected to deposit directly onto the bonding layer. In order to confirm the interaction between the DP-bioactive glass and bone tissue, the developed bioactive glass was implanted into rabbit femur condyle for 2-32 weeks. The histological evaluation of DP-bioactive glass as a bone substitute was also investigated in the study. Porous hydroxyapatite bioceramic was used in the control group and the results were compared with those of DP-bioactive glass. The interface between the DP-bioactive glass and bone tissue examined with SEM-EPMA showed that the bioactive glass formed a reaction layer on the surface within 2 weeks after operation and formed a direct bond with natural bone. The elements contained in the bioactive glass apparently interdiffuse with the living bone and biological hydroxyapatite deposited onto the diffusion area, which was proved by EPMA and TEM. After implantation for over 8 weeks, the DP-bioactive glass was gradually biodegraded and absorbed by the living bone. Histological examination using the optical microscope showed that osteocytes grow into the inside of the DP-bioactive glass and the bioactive glass would be expected to be a part of bone. PMID:7888580

Lin, F H; Lin, C C; Liu, H C; Huang, Y Y; Wang, C Y; Lu, C M

1994-10-01

104

A solanesol-derived scaffold for multimerization of bioactive peptides.  

PubMed

A flexible molecular scaffold bearing varying numbers of terminal alkyne groups was synthesized in five steps from solanesol. R(CO)-MSH(4)-NH(2) ligands, which have a relatively low affinity for binding at the human melanocortin 4 receptor (hMC4R), were prepared by solid phase synthesis and were N-terminally acylated with 6-azidohexanoic acid. Multiple copies of the azide N(3)(CH(2))(5)(CO)-MSH(4)-NH(2) were attached to the alkyne-bearing, solanesol-derived molecular scaffold via the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Control studies showed that the binding affinity of the triazole-containing ligand, CH(3)(CH(2))(3)(C(2)N(3))(CH(2))(5)(CO)-MSH(4)-NH(2), was not significantly diminished relative to the corresponding parental ligand, CH(3)(CO)-MSH(4)-NH(2). In a competitive binding assay with a Eu-labeled probe based on the superpotent ligand NDP-alpha-MSH, the monovalent and multivalent constructs appear to bind to hMC4R as monovalent species. In a similar assay with a Eu-labeled probe based on MSH(4), modest increases in binding potency with increased MSH(4) content per scaffold were observed. PMID:20701315

Alleti, Ramesh; Rao, Venkataramanarao; Xu, Liping; Gillies, Robert J; Mash, Eugene A

2010-09-01

105

A Solanesol-derived Scaffold for Multimerization of Bioactive Peptides  

PubMed Central

A flexible molecular scaffold bearing varying numbers of terminal alkyne groups was synthesized in five steps from solanesol. R(CO)-MSH(4)-NH2 ligands, which have a relatively low affinity for binding at the human melanocortin 4 receptor (hMC4R), were prepared by solid phase synthesis and were N-terminally acylated using 6-azidohexanoic acid. Multiple copies of the azide N3(CH2)5(CO)-MSH(4)-NH2 were attached to the alkyne-bearing, solanesol-derived molecular scaffold via the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Control studies showed that the binding affinity of the triazole-containing ligand, CH3(CH2)3(C2N3)(CH2)5(CO)-MSH(4)-NH2, was not significantly diminished relative to the corresponding parental ligand, CH3(CO)-MSH(4)-NH2. In a competitive binding assay using a Eu-labeled probe based on the superpotent ligand NDP-?-MSH, the monovalent and multivalent constructs appear to bind to hMC4R as monovalent species. In a similar assay using a Eu-labeled probe based on MSH(4), modest increases in binding potency with increased MSH(4) content per scaffold were observed.

Alleti, Ramesh; Rao, Venkataramanarao; Xu, Liping; Gillies, Robert J.; Mash, Eugene A.

2010-01-01

106

Strength and toughness of tape cast bioactive glass 45S5 following heat treatment  

Microsoft Academic Search

Tape cast and sintered (TCS) bioactive glass 45S5 has been shown to exhibit in vitro bioactivity in SBF and Tris, despite the formation of a crystalline phase (Na2Ca2Si3O9) during heat treatment. In this work, the effective porosity, hardness and flexural strength of TCS bioactive ceramic (composed of bioactive glass 45S5 prior to heat treatment) was determined as a function of

D. C Clupper; L. L Hench; J. J Mecholsky

2004-01-01

107

Porous bioactive glass and glass-ceramics made by reaction sintering under pressure.  

PubMed

A glass and a rhenanite-wollastonite glass-ceramic were synthesized with the qualitative composition Na2O-CaO-SiO2-P2O5. Both materials were prepared by reaction sintering under isostatic pressure (RSIP) using powder mixtures. Solid state reactions were complete within a few hours at 950 degrees C under modest pressure. Formation of the glass and crystalline phases was driven by an intermediate, reactive, low viscosity Na2O-SiO2 phase. A reaction mechanism is suggested. Porous materials were obtained with two ranges of pore sizes: 100-200 microm and < or =5 microm in diameter. The glass and the glass-ceramic were corroded in simulated body fluid at 37 degrees C. The evolution of surface features was studied. Gel layers formed on both materials. Corrosion was fastest inside the pores. Microcrystals of apatite were identified by crystal structure analysis and by chemical analysis. During corrosion of the glass-ceramic, rhenanite most likely was converted into apatite. Comparison of these results with published information suggests that the glass and glass-ceramic are bioactive. We suggest that RSIP can be used (a) to control the surface porosity and pore size of bioactive implants, thereby increasing the stability of tissue/implant interfaces; (b) to make glasses and glass-ceramics with new properties; and (c) to make near net-shape materials. PMID:11189036

Gong, W; Abdelouas, A; Lutze, W

2001-03-01

108

Bone cell responses of titanium blasted with bioactive glass particles.  

PubMed

Surface modification of Ti-based metals is an important issue in improving the bone cell responses and bone-implant integration. Blasting Ti with granules (mostly alumina) is commonly used to prepare a clean surface and provide a level of roughness. In this study, glass granules with a bioactive composition were used as the blasting source to improve the surface bioactivity and biocompatibility of a Ti substrate. Bioactive glass particles with a composition of 70SiO(2) * 25CaO * 5P(2)O(5) were prepared using a sol-gel method. A Ti disc was blasted with glass particles using a dental blasting unit (BG-Ti). A Ti disc blasted with commercial spherical-shaped glass (G-Ti) and a disc without blasting (Ti) were also prepared for comparison. The blasted Ti contained a large number of glass particles after the blasting process. The surface roughness of the samples in ascending order was G-Ti>BG-Ti>Ti. Murine-derived preosteoblasts (MC3T3-E1) were seeded on the samples, and the cell growth, differentiation, and mineralization behaviors were observed. The osteoblastic cells attached well and spread actively over all the sample groups with extensive cytoskeletal processes. The level of cell growth on the BG-Ti showed a continual increase with culturing up to 7 days, showing good cell viability. However, there was no significant difference (ANOVA, p<0.05) with respect to the G-Ti and Ti groups. In particular, the alkaline phosphatase (AP) activity of the cells was significantly higher on the BG-Ti than on the other groups after culturing for 14 days. Moreover, the mineralization behavior of the cells, as assessed by Alizarin S Red, was superior on the BG-Ti to that observed on the other groups after culturing for 14 and 28 days. Overall, the blasting of Ti with a bioactive glass composition is considered beneficial for producing substrates with enhanced osteogenic potential. PMID:19737811

Choi, Chang-Rak; Yu, Hye-Sun; Kim, Chul-Hwan; Lee, Jae-Hoon; Oh, Chung-Hun; Kim, Hae-Won; Lee, Hae-Hyoung

2009-09-08

109

Degradable polyester scaffolds with controlled surface chemistry combining minimal protein adsorption with specific bioactivation.  

PubMed

Advanced biomaterials and scaffolds for tissue engineering place high demands on materials and exceed the passive biocompatibility requirements previously considered acceptable for biomedical implants. Together with degradability, the activation of specific cell–material interactions and a three-dimensional environment that mimics the extracellular matrix are core challenges and prerequisites for the organization of living cells to functional tissue. Moreover, although bioactive signalling combined with minimization of non-specific protein adsorption is an advanced modification technique for flat surfaces, it is usually not accomplished for three-dimensional fibrous scaffolds used in tissue engineering. Here, we present a one-step preparation of fully synthetic, bioactive and degradable extracellular matrix-mimetic scaffolds by electrospinning, using poly(D,L-lactide-co-glycolide) as the matrix polymer. Addition of a functional, amphiphilic macromolecule based on star-shaped poly(ethylene oxide) transforms current biomedically used degradable polyesters into hydrophilic fibres, which causes the suppression of non-specific protein adsorption on the fibres’ surface. The subsequent covalent attachment of cell-adhesion-mediating peptides to the hydrophilic fibres promotes specific bioactivation and enables adhesion of cells through exclusive recognition of the immobilized binding motifs. This approach permits synthetic materials to directly control cell behaviour, for example, resembling the binding of cells to fibronectin immobilized on collagen fibres in the extracellular matrix of connective tissue. PMID:21151163

Grafahrend, Dirk; Heffels, Karl-Heinz; Beer, Meike V; Gasteier, Peter; Möller, Martin; Boehm, Gabriele; Dalton, Paul D; Groll, Jürgen

2011-01-01

110

Release of bioactive adeno-associated virus from fibrin scaffolds: effects of fibrin glue concentrations.  

PubMed

Fibrin glue (FG) is used in a variety of clinical applications and in the laboratory for localized and sustained release of factors potentially important for tissue engineering. However, the effect of different fibrinogen concentrations on FG scaffold delivery of bioactive adeno-associated viruses (AAVs) has not been established. This study was performed to test the hypothesis that FG concentration alters AAV release profiles, which affect AAV bioavailability. Gene transfer efficiency of AAV-GFP released from FG was measured using HEK-293 cells. Bioactivity of AAV transforming growth factor-beta1 (TGF-?(1)) released from FG was assessed using the mink lung cell assay, and by measuring induction of cartilage-specific gene expression in human mesenchymal stem cells (hMSCs). Nondiluted FG had longer clotting times, smaller pore sizes, thicker fibers, and slower dissolution rate, resulting in reduced release of AAV. AAV release and gene transfer efficiency was higher with 25% and 50% FG than with the 75% and 100% FG. AAV-TGF-?(1) released from dilute-FG transduced hMSCs, resulting in higher concentrations of bioactive TGF-?(1) and greater upregulation of cartilage-specific gene expression compared with hMSC from undiluted FG. This study, showing improved release, transduction efficiency, and chondrogenic effect on hMSC of bioactive AAV-TGF-?(1) released from diluted FG, provides information important to optimization of this clinically available scaffold for therapeutic gene delivery, both in cartilage regeneration and for other tissue engineering applications. PMID:21449684

Lee, Hannah H; Haleem, Amgad M; Yao, Veronica; Li, Juan; Xiao, Xiao; Chu, Constance R

2011-05-11

111

Flame Spray Deposition of Titanium Alloy-Bioactive Glass Composite Coatings  

NASA Astrophysics Data System (ADS)

Powders of titanium alloy (Ti-6Al-4V) and bioactive glass (45S5) were deposited by flame spraying to fabricate composite porous coatings for potential use in bone fixation implants. Bioactive glass and titanium alloy powder were blended and deposited in various weight fractions under two sets of spray conditions, which produced different levels of porosity. Coatings were characterized with cross-sectional optical microscopy, x-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Immersion testing in simulated body fluid (SBF) was conducted for 0, 1, 7, and 14 days. Hydroxyapatite (HA) was found on the bioactive glass-alloy composite coatings after 7 days of immersion; no HA was observed after 14 days on the pure titanium alloy control coating. The HA formation on the alloy-bioactive glass composite coating suggests that the addition of bioactive glass to the blend may greatly increase the bioactivity of the coating through enhanced surface mineralization.

Nelson, G. M.; Nychka, J. A.; McDonald, A. G.

2011-12-01

112

Indigenous hydroxyapatite coated and bioactive glass coated titanium dental implant system - Fabrication and application in humans  

PubMed Central

Background: The use of different bioactive materials as coating on dental implant to restore tooth function is a growing trend in modern Dentistry. In the present study, hydroxyapatite and the bioactive glass-coated implants were evaluated for their behavior in osseous tissue following implantation in 14 patients. Materials and Methods: Bioactive glass and hydroxyapatite formulated and prepared for coating on Ti-6Al-4V alloy. Hydroxyapatite coating was applied on the implant surface by air plasma spray technique and bioactive glass coating was applied by vitreous enameling technique. Their outcome was assessed after 6 months in vivo study in human. Results: Hydroxyapatite and bioactive glass coating materials were nontoxic and biocompatible. Uneventful healing was observed with both types of implants. Conclusion: The results showed bioactive glass is a good alternative coating material for dental implant.

Mistry, Surajit; Kundu, Debabrata; Datta, Someswar; Basu, Debabrata; Soundrapandian, Chidambaram

2011-01-01

113

Fluoride release and bioactivity evaluation of glass ionomer: Forsterite nanocomposite  

PubMed Central

Background: The most important limitation of glass ionomer cements (GICs) is the weak mechanical properties. Our previous research showed that higher mechanical properties could be achieved by addition of forsterite (Mg2SiO4) nanoparticles to ceramic part of GIC. The objective of the present study was to fabricate a glass ionomer- Mg2SiO4 nanocomposite and to evaluate the effect of addition of Mg2SiO4 nanoparticles on bioactivity and fluoride release behavior of prepared nanocomposite. Materials and Methods: Forsterite nanoparticles were made by sol-gel process. X-ray diffraction (XRD) technique was used in order to phase structure characterization and determination of grain size of Mg2SiO4 nanopowder. Nanocomposite was fabricated via adding 3wt.% of Mg2SiO4 nanoparticles to ceramic part of commercial GIC (Fuji II GC). Fluoride ion release and bioactivity of nanocomposite were measured using the artificial saliva and simulated body fluid (SBF), respectively. Bioactivity of specimens was investigated by Fourier transitioned-infrared spectroscopy (FTIR), scanning electronmicroscopy (SEM), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and registration of the changes in pH of soaking solution at the soaking period. Statistical analysis was carried out by one Way analysis of variance and differences were considered significant if P < 0.05. Results: The results of XRD analysis confirmed that nanocrystalline and pure Mg2SiO4 powder was obtained. Fluoride ion release evaluation showed that the values of released fluoride ions from nanocomposite are somewhat less than Fuji II GC. SEM images, pH changes of the SBF and results of the ICP-OES and FTIR tests confirmed the bioactivity of the nanocomposite. Statistical analysis showed that the differences between the results of all groups were significant (P < 0.05). Conclusion: Glass ionomer- Mg2SiO4 nanocomposite could be a good candidate for dentistry and orthopedic applications, through of desirable fluoride ion release and bioactivity.

Sayyedan, Fatemeh Sadat; Fathi, Mohammadhossein; Edris, Hossein; Doostmohammadi, Ali; Mortazavi, Vajihesadat; Shirani, Farzaneh

2013-01-01

114

A Sucrose-derived Scaffold for Multimerization of Bioactive Peptides  

PubMed Central

A spherical molecular scaffold bearing eight terminal alkyne groups was synthesized in one step from sucrose. One or more copies of a tetrapeptide azide, either N3(CH2)5(C=O)-His-dPhe-Arg-Trp-NH2 (MSH4) or N3(CH2)5(C=O)-Trp-Met-Asp-Phe-NH2 (CCK4), were attached to the scaffold via the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Competitive binding assays using Eu-labeled probes based on the superpotent ligands Ser-Tyr-Ser-Nle-Glu-His-dPhe-Arg-Trp-Gly-Lys-Pro-Val-NH2 (NDP-?-MSH) and Asp-Tyr-Met-Gly-Trp-Met-Asp-Phe-NH2 (CCK8) were used to study the interactions of monovalent and multivalent MSH4 and CCK4 constructs with Hek293 cells engineered to overexpress MC4R and CCK2R. All of the monovalent and multivalent MSH4 constructs exhibited binding comparable to that of the parental ligand, suggesting that either the ligand spacing was inappropriate for multivalent binding, or MSH4 is too weak a binder for a second “anchoring” binding event to occur before the monovalently-bound construct is released from the cell surface. In contrast with this behavior, monovalent CCK4 constructs were significantly less potent than the parental ligand, while multivalent CCK4 constructs were as or more potent than the parental ligand. These results are suggestive of multivalent binding, which may be due to increased residence times for monovalently bound CCK4 constructs on the cell surface relative to MSH4 constructs, the greater residence time being necessary for the establishment of multivalent binding.

Rao, Venkataramanarao; Alleti, Ramesh; Xu, Liping; Tafreshi, Narges K.; Morse, David L.; Gillies, Robert J.; Mash, Eugene A.

2011-01-01

115

Protein interactions with nanoporous sol-gel derived bioactive glasses.  

PubMed

Sol-gel derived bioactive glasses are excellent candidates for bone regenerative implant materials as they bond with bone, stimulate bone growth and degrade in the body. Their interactions with proteins are critical to understanding their performance after implantation. This study focuses on the interactions between fibrinogen and sol-gel glass particles of the 70S30C (70 mol.% SiO(2), 30 mol.% CaO composition). Sol-gel silica and melt-derived Bioglass® were also used for comparison. Fibrinogen penetration into the nanoporous glasses was observed by live tracking the fluorescent-labelled fibrinogen with confocal microscopy. The effect of pore size on protein penetration was investigated. Nanoporous networks with modal pore diameters larger than 6 nm were accessible to fibrinogen. When the modal nanopore diameter was decreased to 2 nm or less, the penetration of fibrinogen was inhibited. The surface properties of the glasses, which can be modulated by media pH, glass composition and final stabilisation temperature in the sol-gel process, have effects on fibrinogen adsorption via long-range Coulombic forces before the adsorption and via short-range interactions such as hydrogen bonding after the adsorption. PMID:21757036

Lin, Sen; Van den Bergh, Wouter; Baker, Simon; Jones, Julian R

2011-06-30

116

Bioactive glass-polymer materials for controlled release of ibuprofen.  

PubMed

The ibuprofen (IB) release from samples composed by SiO2-CaO-P2O5 bioactive glass, poly-L-lactic acid (PLA), and polymethylmethacrylate (PMMA) has been studied. Data showed a fast anti-inflammatory drug release during the first 8h when these polyphasic materials are soaked in simulated body fluid (SBF). The analysis of the samples before and after different soaking periods in SBF demonstrates the growth of an apatite-like layer on the materials surface. The IB release rate is related with the growth kinetics of this layer, that is slower when the materials do not contain the biodegradable polymer PLA. On the other hand, different IB and/or glass contents do not affect the in vitro behavior of these materials. PMID:12834599

Ladrón de Guevara-Fernández, S; Ragel, C V; Vallet-Regí, M

2003-10-01

117

A modular and supramolecular approach to bioactive scaffolds for tissue engineering  

NASA Astrophysics Data System (ADS)

Bioactive polymeric scaffolds are a prerequisite for the ultimate formation of functional tissues. Here, we show that supramolecular polymers based on quadruple hydrogen bonding ureido-pyrimidinone (UPy) moieties are eminently suitable for producing such bioactive materials owing to their low-temperature processability, favourable degradation and biocompatible behaviour. Particularly, the reversible nature of the hydrogen bonds allows for a modular approach to gaining control over cellular behaviour and activity both in vitro and in vivo. Bioactive materials are obtained by simply mixing UPy-functionalized polymers with UPy-modified biomolecules. Low-molecular-weight bis-UPy-oligocaprolactones with cell adhesion promoting UPy-Gly-Arg-Gly-Asp-Ser (UPy-GRGDS) and the synergistic UPy-Pro-His-Ser-Arg-Asn (UPy-PHSRN) peptide sequences are synthesized and studied. The in vitro results indicate strong and specific cell binding of fibroblasts to the UPy-functionalized bioactive materials containing both UPy-peptides. An even more striking effect is seen in vivo where the formation of single giant cells at the interface between bioactive material and tissue is triggered.

Dankers, Patricia Y. W.; Harmsen, Martin C.; Brouwer, Linda A.; van Luyn, Marja J. A.; Meijer, E. W.

2005-07-01

118

Resorbable glass-ceramic phosphate-based scaffolds for bone tissue engineering: synthesis, properties, and in vitro effects on human marrow stromal cells.  

PubMed

Highly porous bioresorbable glass-ceramic scaffolds were prepared via sponge replication method by using an open-cell polyurethane foam as a template and phosphate-based glass powders. The glass, belonging to the P2O5-SiO2-CaO-MgO-Na2O-K2O system, was synthesized by a melting-quenching route, ground, and sieved to obtain powders with a grain size of less than 30??m. A slurry containing glass powders, polyvinyl alcohol, and water was prepared to coat the polymeric template. The removal of the polymer and the sintering of the glass powders were performed by a thermal treatment, in order to obtain an inorganic replica of the template structure. The structure and properties of the scaffold were investigated from structural, morphological, and mechanical viewpoints by means of X-ray diffraction, scanning electron microscopy, density measurements, image analysis, and compressive tests. The scaffolds exhibited a trabecular architecture that closely mimics the structure of a natural spongy bone. The solubility of the porous structures was assessed by soaking the samples in acellular simulated body fluid (SBF) and Tris-HCl for different time frames and then by assessing the scaffold weight loss. As far as the test in SBF is concerned, the nucleation of hydroxyapatite on the scaffold trabeculae demonstrates the bioactivity of the material. Biological tests were carried out using human bone marrow stromal cells to test the osteoconductivity of the material. The cells adhered to the scaffold struts and were metabolically active; it was found that cell differentiation over proliferation occurred. Therefore, the produced scaffolds, being biocompatible, bioactive, resorbable, and structurally similar to a spongy bone, can be proposed as interesting candidates for bone grafting. PMID:20566654

Vitale-Brovarone, Chiara; Ciapetti, Gabriela; Leonardi, Elisa; Baldini, Nicola; Bretcanu, Oana; Verné, Enrica; Baino, Francesco

2010-06-21

119

Chitosan/bioactive glass nanoparticle composite membranes for periodontal regeneration.  

PubMed

Barrier membranes are used in periodontal applications with the aim of supporting periodontal regeneration by physically blocking migration of epithelial cells. The present work proposes a combination of chitosan (CHT) with bioactive glass nanoparticles (BG-NPs) in order to produce a novel guided tissue and bone regeneration membrane, fabricated by solvent casting. The CHT/BG-NP nanocomposite membranes are characterized in terms of water uptake, in mechanical tests, under simulated physiological conditions and in in vitro bioactivity tests. The addition of BG-NPs to CHT membranes decreased the mechanical potential of these membranes, but on the other hand the bioactivity improved. The membranes containing the BG-NPs induced the precipitation of bone-like apatite in simulated body fluid (SBF). Biological tests were carried out using human periodontal ligament cells and human bone marrow stromal cells. CHT/BG-NP composite membranes promoted cell metabolic activity and mineralization. The results indicate that the CHT/BG-NP composite membrane could potentially be used as a temporary guided tissue regeneration membrane in periodontal regeneration, with the possibility to induce bone regeneration. PMID:22771458

Mota, Joana; Yu, Na; Caridade, Sofia G; Luz, Gisela M; Gomes, Manuela E; Reis, Rui L; Jansen, John A; Walboomers, X Frank; Mano, João F

2012-07-05

120

Local protective effects of oral 45S5 bioactive glass on gastric ulcers in experimental animals.  

PubMed

Bioactive glass has been shown to stimulate bone regeneration and soft tissue healing. In this study, we evaluated the local protective effects of bioactive glass on experimental gastric ulcers, in comparison with omeprazole and hydrotalcite. Single and multiple gavage of 45S5 bioactive glass dose-dependently protected stress ulcers in mice and chronic ulcers in rats. Multi-daily gavage of bioactive glass for 7 days prevented chronic ulcer recurrence by 50 %. Bioactive glass ionic dissolution produced marked proliferation of ethanol-injured GES-1 human gastric mucosa epithelial cells 48 and 72 h after exposure. Bioactive glass was shown to be hardly absorbed after single or multi-daily gavage. This study, for the first time, demonstrates that bioactive glass is effective in protecting against gastric ulcers, with its high efficacy comparable to omeprazole and superior to hydrotalcite. The lack of oral absorption makes bioactive glass a potential for treatment of peptic ulcers omitting systemic toxicity or side-effects. PMID:23329370

Ma, Ai-niu; Gong, Nian; Lu, Jin-miao; Huang, Jin-lu; Hao, Bin; Guo, Yang; Zhong, Jipin; Xu, Yuhong; Chang, Jiang; Wang, Yong-xiang

2013-01-18

121

Predicting the bioactivity of glasses using the network connectivity or split network models  

Microsoft Academic Search

Bioactive glasses (BG) are used as bone substitutes and re-mineralising additives in toothpastes. They work by precipitating apatite on their surface, and the network connectivity (NC) and split network models can be used to predict their bioactivity, i.e. their ability to form apatite.While NC predicts glass degradation and has been used successfully to predict the bioactivity of BG, it does

Robert G. Hill; Delia S. Brauer

2011-01-01

122

Nano-Hydroxyapatite/Fluoridated and Unfluoridated Bioactive Glass Composites: Structural Analysis and Bioactivity Evaluation  

NASA Astrophysics Data System (ADS)

Biphasic bioceramic composites containing nano-hydroxyapatite (HAP) and nanosized bioactive glasses have been prepared in the form of pellets and have been examined for the effects of bioglass concentrations and sintering temperature on the structural transformations and bioactivity behavior. Pure stoichiometric nano-HAP was synthesized using sol-gel technique. Two bioglasses synthesized in this work--fluoridated bioglass (Cao-P2O5-Na2O3-CaF2) and unfluoridated bioglass (Cao-P2O5-Na2O3) designated as FBG and UFBG respectively, were added to nano-HAP with concentrations of 5, 10, 12 and 15%. The average particle sizes of synthesized HAP and bioglasses were 23 nm and 35 nm, respectively. The pellets were sintered at four different temperatures i.e. 1000 °C, 1150 °C, 1250 °C and 1350 °C. The investigations involved study of structural and bioactivity behavior of green and sintered pellets and their deviations from original materials i.e. HAP, FBG and UFBG, using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The phase composition of the sintered pellets was found to be non-stoichiometric HAP with ?-TCP (tricalcium phosphate) and ?-TCP. It was revealed from SEM images that bonding mechanism was mainly solid state sintering for all pellets sintered at 1000 °C and 1150 °C and also for pellets with lower concentrations of bioglass i.e. 5% and 10% sintered at 1250 °C. Partly liquid phase sintering was observed for pellets with higher bioglass concentrations of 12% and 15% sintered at 1250 °C and same behaviour was noted for pellets at all concentrations of bioglasses at 1350 °C. The sintered density, hardness and compression strength of pellets have been influenced both by the concentration of the bioglasses and sintering temperature. It was observed that the biological HAP layer formation was faster on the green pellets surface than on pure HAP and sintered pellets, showing higher bioactivity in the green pellets.

Batra, Uma; Kapoor, Seema; Sharma, J. D.

2011-12-01

123

In vitro bioactivity, cytocompatibility, and antibiotic release profile of gentamicin sulfate-loaded borate bioactive glass/chitosan composites.  

PubMed

Borate bioactive glass-based composites have been attracting interest recently as an osteoconductive carrier material for local antibiotic delivery. In the present study, composites composed of borate bioactive glass particles bonded with a chitosan matrix were prepared and evaluated in vitro as a carrier for gentamicin sulfate. The bioactivity, degradation, drug release profile, and compressive strength of the composite carrier system were studied as a function of immersion time in phosphate-buffered saline at 37 °C. The cytocompatibility of the gentamicin sulfate-loaded composite carrier was evaluated using assays of cell proliferation and alkaline phosphatase activity of osteogenic MC3T3-E1 cells. Sustained release of gentamicin sulfate occurred over ~28 days in PBS, while the bioactive glass converted continuously to hydroxyapatite. The compressive strength of the composite loaded with gentamicin sulfate decreased from the as-fabricated value of 24 ± 3 MPa to ~8 MPa after immersion for 14 days in PBS. Extracts of the soluble ionic products of the borate glass/chitosan composites enhanced the proliferation and alkaline phosphatase activity of MC3T3-E1 cells. These results indicate that the gentamicin sulfate-loaded composite composed of chitosan-bonded borate bioactive glass particles could be useful clinically as an osteoconductive carrier material for treating bone infection. PMID:23820937

Cui, Xu; Gu, Yifei; Li, Le; Wang, Hui; Xie, Zhongping; Luo, Shihua; Zhou, Nai; Huang, Wenhai; Rahaman, Mohamed N

2013-07-03

124

A new synthesis route to high surface area sol gel bioactive glass through alcohol washing  

PubMed Central

Bioactive glass is one of the widely used bone repair material due to its unique properties like osteoconductivity, osteoinductivity and biodegradability. In this study bioactive glass is prepared by the sol gel process and stabilized by a novel method that involves a solvent instead of the conventional calcinations process. This study represents the first attempt to use this method for the stabilization of bioactive glass. The bioactive glass stabilized by this ethanol washing process was characterized for its physicochemical and biomimetic property in comparison with similar composition of calcined bioactive glass. The compositional similarity of the two stabilized glass powders was confirmed by spectroscopic and thermogravimetric analysis. Other physicochemical characterizations together with the cell culture studies with L929 fibroblast cells and bone marrow mesenchymal stem cells proved that the stabilization was achieved with the retention of its inherent bioactive potential. However an increase in the surface area of the glass powder was obtained as a result of this ethanol washing process and this add up to the success of the study. Hence the present study exhibits a promising route for high surface area bioactive glass for increasing biomimicity.

M. Mukundan, Lakshmi; Nirmal, Remya; Vaikkath, Dhanesh; Nair, Prabha D.

2013-01-01

125

Functionally graded bioactive glass coating on magnesia partially stabilized zirconia (Mg-PSZ) for enhanced biocompatibility.  

PubMed

The coating of magnesia partially stabilized zirconia (Mg-PSZ) with a bioactive glass was investigated for enhancing the bioactivity and bone-bonding ability of Mg-PSZ orthopedic implants. Individual coatings of three different bioactive glasses were prepared by depositing a concentrated suspension of the glass particles on Mg-PSZ substrates, followed by sintering at temperatures between 750 degrees C and 850 degrees C. Two silicate-based glass compositions (designated 13-93 and 6P68), and a borosilicate glass composition (H12) were investigated. The microstructure and adhesive strength of the coatings were characterized, and the in vitro bioactivity of the glasses was compared by measuring their conversion kinetics to hydroxyapatite in an aqueous phosphate solution at 37 degrees C. The 6P68 glass provided the highest adhesive strength (40 +/- 2 MPa) but showed very limited bioactivity, whereas the H12 glass had lower adhesive strength (18 +/- 2 MPa) but the highest bioactivity. A functionally graded coating, consisting of a 6P68 interfacial layer and an H12 surface layer, was developed to provide a coating with high adhesive strength coupled with rapid in vitro bioactivity. PMID:18157512

Rahaman, Mohamed N; Li, Yadong; Bal, B Sonny; Huang, Wenhai

2007-12-23

126

Bioabsorbable scaffolds for guided bone regeneration and generation  

Microsoft Academic Search

Several different bioabsorbable scaffolds designed and manufactured for guided bone regeneration and generation have been developed. In order to enhance the bioactivity and potential osteoconductivity of the scaffolds, different bioabsorbable polymers, composites of polymer and bioactive glass, and textured surface structures of the manufactured devices and composites were investigated in in vitro studies and experimental animal models. Solid, self-reinforced polyglycolide

Minna Kellomäki; Henna Niiranen; Katja Puumanen; Nureddin Ashammakhi; Timo Waris; Pertti Törmälä

2000-01-01

127

Development of nano-macroporous soda-lime phosphofluorosilicate bioactive glass and glass-ceramics.  

PubMed

We have extended the usefulness of bioactive glass-ceramics for the repair and reconstruction of hard tissues by introducing F ions that are known to be beneficial, especially in dentistry. Nano-macro multimodal porosity in soda-lime phosphofluorosilicate bulk samples was introduced by the recently developed melt-quench-heat-etch method. The choice of starting glass composition is based on 48SiO2-2.7P2O5-xCaF2-yCaO-zNa2O where x = 0, 1, 4, 8, 10, 12, and (y + z) = 49.3-x (mol%). The effect of thermal and chemical treatment on the microstructure of samples is characterized by SEM, XRD and EDX. We find the formation of many crystalline phases, but mainly sodium calcium silicate, calcium phosphate, fluorapatite and calcium silicate. The bioactivity of soda-lime phosphofluorosilicate glass-ceramics is assessed by monitoring the formation of hydroxyl apatite (HA) layer: fluorapatite phase accelerates the rate of HA layer formation; the initial composition and multi-modal porosity are other key parameters that impact the formation of HA. The present porous glass-ceramics should be superior candidates for use in dental bone regeneration. PMID:19252969

Moawad, H M M; Jain, H

2009-02-28

128

Nano-Hydroxyapatite/Fluoridated and Unfluoridated Bioactive Glass Composites: Structural Analysis and Bioactivity Evaluation  

SciTech Connect

Biphasic bioceramic composites containing nano-hydroxyapatite (HAP) and nanosized bioactive glasses have been prepared in the form of pellets and have been examined for the effects of bioglass concentrations and sintering temperature on the structural transformations and bioactivity behavior. Pure stoichiometric nano-HAP was synthesized using sol-gel technique. Two bioglasses synthesized in this work--fluoridated bioglass (Cao-P{sub 2}O{sub 5}-Na{sub 2}O{sub 3}-CaF{sub 2}) and unfluoridated bioglass (Cao-P{sub 2}O{sub 5}-Na{sub 2}O{sub 3}) designated as FBG and UFBG respectively, were added to nano-HAP with concentrations of 5, 10, 12 and 15%. The average particle sizes of synthesized HAP and bioglasses were 23 nm and 35 nm, respectively. The pellets were sintered at four different temperatures i.e. 1000 deg. C, 1150 deg. C, 1250 deg. C and 1350 deg. C. The investigations involved study of structural and bioactivity behavior of green and sintered pellets and their deviations from original materials i.e. HAP, FBG and UFBG, using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The phase composition of the sintered pellets was found to be non-stoichiometric HAP with {alpha}-TCP (tricalcium phosphate) and {beta}-TCP. It was revealed from SEM images that bonding mechanism was mainly solid state sintering for all pellets sintered at 1000 deg. C and 1150 deg. C and also for pellets with lower concentrations of bioglass i.e. 5% and 10% sintered at 1250 deg. C. Partly liquid phase sintering was observed for pellets with higher bioglass concentrations of 12% and 15% sintered at 1250 deg. C and same behaviour was noted for pellets at all concentrations of bioglasses at 1350 deg. C. The sintered density, hardness and compression strength of pellets have been influenced both by the concentration of the bioglasses and sintering temperature. It was observed that the biological HAP layer formation was faster on the green pellets surface than on pure HAP and sintered pellets, showing higher bioactivity in the green pellets.

Batra, Uma [Department of Materials and Metallurgical Engineering, PEC University of Technology, Chandigarh-160012 (India); Kapoor, Seema [University Institute of Chemical Engineering and Technology, Panjab University, Chandigarh-160014 (India); Sharma, J. D. [Department of Materials and Metallurgical Engineering, PEC University of Technology, Chandigarh (India)

2011-12-12

129

Fluorine environment in bioactive glasses: ab initio molecular dynamics simulations.  

PubMed

Fluorinated bioactive glasses (FBGs) combine the antibacterial properties of fluorine with the biological activity of phosphosilicate glasses. Because their biomedical application depends on the release of fluorine, the detailed characterization of the fluorine environment in FBGs is the key to understand their properties. Car-Parrinello molecular dynamics (CPMD) simulations have been performed on a 45S5 Bioglass composition in which 10 mol % of the CaO has been replaced with CaF(2), and have allowed us to resolve some longstanding issues about the atomic structure of fluorinated bioglasses, with particular regard to the structural role of fluorine. F is coordinated almost entirely to the modifier ions Na and Ca, with a very small amount of residual Si-F bonds, whose fraction only becomes significant in the melt precursor. High temperature leads to Si-F bonds in both tetra- (SiO(3)F) and, less frequently, penta-coordinated (SiO(4)F and SiO(3)F(2)) complexes, showing that formation of these bonds through the expansion of the SiO(4) coordination shell is generally less favored. There is no evidence for preferential bonding of F to either modifier ion: almost all F atoms are coordinated to both calcium and sodium in a "mixed state", rather than exclusively to either, as had been conjectured. We discuss the consequences of these findings on the properties of fluorine-containing bioglasses. PMID:21322627

Christie, Jamieson K; Pedone, Alfonso; Menziani, Maria Cristina; Tilocca, Antonio

2011-02-15

130

Synthesis and characterization of chitosan-polyvinyl alcohol-bioactive glass hybrid membranes  

PubMed Central

The tissue engineering strategy is a new approach for the regeneration of cementum, which is essential for the regeneration of the periodontal tissue. This strategy involves the cell cultures present in this tissue, called cementoblasts, and located on an appropriate substrate for posterior implantation in the regeneration site. Prior studies from our research group have shown that the proliferation and viability of cementoblasts increase in the presence of the ionic dissolution products of bioactive glass particles. Therefore, one possible approach to obtaining adequate substrates for cementoblast cultures is the development of composite membranes containing bioactive glass. In the present study, composite films of chitosan-polyvinyl alcohol-bioactive glass containing different glass contents were developed. Glutaraldehyde was also added to allow for the formation of cross-links and changes in the degradation rate. The glass phase was introduced in the material by a sol-gel route, leading to an organic-inorganic hybrid. The films were characterized by Fourier-transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with electron dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis. Bioactivity tests were also conducted by immersion of the films in simulated body fluid (SBF). Films containing up to 30% glass phase could be obtained. The formation of calcium phosphate was observed after the immersion of the films. A calcium phosphate layer formed more quickly on materials containing higher bioactive glass contents. In the hybrid containing 23% bioactive glass, a complete layer was formed after 24 h immersion, showing the high bioactivity of this material. However, despite the higher in vitro bioactivity, the film with 23% glass showed lower mechanical properties compared with films containing up to 17% glass.

Dias, Luisa L.S.; Mansur, Herman S.; Donnici, Claudio Luis; Pereira, Marivalda M.

2011-01-01

131

Synthesis and characterization of chitosan-polyvinyl alcohol-bioactive glass hybrid membranes.  

PubMed

The tissue engineering strategy is a new approach for the regeneration of cementum, which is essential for the regeneration of the periodontal tissue. This strategy involves the cell cultures present in this tissue, called cementoblasts, and located on an appropriate substrate for posterior implantation in the regeneration site. Prior studies from our research group have shown that the proliferation and viability of cementoblasts increase in the presence of the ionic dissolution products of bioactive glass particles. Therefore, one possible approach to obtaining adequate substrates for cementoblast cultures is the development of composite membranes containing bioactive glass. In the present study, composite films of chitosan-polyvinyl alcohol-bioactive glass containing different glass contents were developed. Glutaraldehyde was also added to allow for the formation of cross-links and changes in the degradation rate. The glass phase was introduced in the material by a sol-gel route, leading to an organic-inorganic hybrid. The films were characterized by Fourier-transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with electron dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis. Bioactivity tests were also conducted by immersion of the films in simulated body fluid (SBF). Films containing up to 30% glass phase could be obtained. The formation of calcium phosphate was observed after the immersion of the films. A calcium phosphate layer formed more quickly on materials containing higher bioactive glass contents. In the hybrid containing 23% bioactive glass, a complete layer was formed after 24 h immersion, showing the high bioactivity of this material. However, despite the higher in vitro bioactivity, the film with 23% glass showed lower mechanical properties compared with films containing up to 17% glass. PMID:23507733

Dias, Luisa L S; Mansur, Herman S; Donnici, Claudio Luis; Pereira, Marivalda M

132

Healing effect of bioactive glass ointment on full-thickness skin wounds.  

PubMed

This study aimed to investigate the effect of bioactive glasses on cutaneous wound healing in both normal rats and streptozotocin-induced diabetic rats. Bioactive glass ointments, prepared by mixing the sol-gel bioactive glass 58S (SGBG-58S), nanobioactive glass (NBG-58S) and the melt-derived 45S5 bioactive glass (45S5) powder with Vaseline (V) at 18% weight percentage, were used to heal full thickness excision wounds. Pure V was used as control in this study. Compared to SGBG-58S, NBG-58S consists of relatively dispersible nanoparticles with smaller size. The analysis of wound healing rate and wound healing time showed that bioactive glasses promoted wound healing. The ointments containing SGBG-58S and NBG-58S healed the wounds more quickly and efficiently than the ointment containing 45S5. Histological examination indicated that bioactive glasses promoted the proliferation of fibroblasts and growth of granulation tissue. Immunohistochemical staining showed that the production of two growth factors, VEGF and FGF2, which are beneficial to wound healing, was also stimulated during the healing process. Transmission electron microscope observations showed that fibroblasts in wounds treated with bioactive glasses contained more rough endoplasmic reticula and had formed new capillary microvessels by the seventh day. The effects of SGBG-58S and NBG-58S were better than those of 45S5. All results suggest that bioactive glasses, especially SGBG-58S and NBG-58S, can accelerate the recovery of skin wounds in both normal and diabetes-impaired healing models and have a great potential for use in wound repair in the future. PMID:22736113

Lin, Cai; Mao, Cong; Zhang, Juanjuan; Li, Yuli; Chen, Xiaofeng

2012-06-27

133

Bioactivity in glass\\/PMMA composites used as drug delivery system  

Microsoft Academic Search

Gentamicin sulfate has been incorporated in composites prepared from a SiO2–CaO–P2O5 bioactive glass and polymethylmethacrylate. Data showed that these materials could be used as drug delivery system, keeping the bioactive behavior of the glass. The composites supply high doses of the antibiotic during the first hours when they are soaked in simulated body fluid (SBF). Thereafter, a slower drug release

D. Arcos; C. V. Ragel; M. Vallet-Reg??

2001-01-01

134

High phosphate content significantly increases apatite formation of fluoride-containing bioactive glasses  

Microsoft Academic Search

Bioactive glass-containing toothpastes for treating dentine hypersensitivity work by precipitating hydroxycarbonate apatite (HCA) onto the tooth surface, but concerns exist over the long-term durability of HCA in the mouth. Fluoride-containing bioactive glasses form fluorapatite (FAp) in physiological solutions, which is more chemically stable against acid attack. The influence of phosphate content on apatite formation was investigated by producing a low-phosphate

Mohammed Mneimne; Robert G. Hill; Andrew J. Bushby; Delia S. Brauer

2011-01-01

135

The effect of the topical administration of bioactive glass on inflammatory markers of human experimental gingivitis  

Microsoft Academic Search

Recent studies demonstrated that bioactive glass attenuated inflammatory reactions and bacterial growth in vitro. The aim of the present clinical study was to evaluate the effects of local bioactive glass-administration in vivo in subjects with experimental gingivitis. In each individual, contralateral teeth served as test and control over a 21-day non-hygiene (preventive phase) and a 7-day therapeutic phase. A 45S5

Jörg Eberhard; Nikolaus Reimers; Hendrik Dommisch; Johanna Hacker; Sandra Freitag; Yahya Acil; Hans-Karl Albers; Sören Jepsen

2005-01-01

136

Synthesis of novel tricalcium phosphate-bioactive glass composite and functionalization with rhBMP-2  

Microsoft Academic Search

A functionalization is required for calcium phosphate-based bone substitute materials to achieve an entire bone remodeling.\\u000a In this study it was hypothesized that a tailored composite of tricalcium phosphate and a bioactive glass can be loaded sufficiently\\u000a with rhBMP-2 for functionalization. A composite of 40 wt% tricalcium phosphate and 60 wt% bioactive glass resulted in two\\u000a crystalline phases, wollastonite and rhenanite after

Karolina Schickle; Kristin Zurlinden; Christian Bergmann; Markus Lindner; Armin Kirsten; Markus Laub; Rainer Telle; Herbert Jennissen; Horst Fischer

2011-01-01

137

Flame Spray Deposition of Titanium Alloy-Bioactive Glass Composite Coatings  

Microsoft Academic Search

Powders of titanium alloy (Ti-6Al-4V) and bioactive glass (45S5) were deposited by flame spraying to fabricate composite porous\\u000a coatings for potential use in bone fixation implants. Bioactive glass and titanium alloy powder were blended and deposited\\u000a in various weight fractions under two sets of spray conditions, which produced different levels of porosity. Coatings were\\u000a characterized with cross-sectional optical microscopy, x-ray

G. M. Nelson; J. A. Nychka; A. G. McDonald

138

Structural characterization of the metal/glass interface in bioactive glass coatings on Ti-6Al-4V  

SciTech Connect

Coating Ti-based implants with bioactive materials promotes joining between the prostheses and the bone as well as increasing long-term implant stability. In the present work, the interface between Ti-6Al-4V and bioactive silicate glass coatings, prepared using a simple enameling technique, is analyzed. High-resolution transmission electron microscopy of the glass/alloy interface shows the formation of a reaction layer ({approx}150 nm thick) composed of Ti5Si3 nanoparticles with a size of {approx}20 nm. This nanostructured interface facilitates the formation of a stable joint between the glass coating and the alloy.

Oku, T.; Suganuma, K.; Wallemberg, L.R.; Tomsia, A.P.; Gomez-Vega, J.M.; Saiz, E.

1999-12-01

139

Preparation and in vitro bioactivity of hydroxyapatite/solgel glass biphasic material.  

PubMed

Hydroxyapatite/solgel glass biphasic material has been obtained in order to improve the bioactivity of the hydroxyapatite (OHAp). A mixture of stoichiometric OHAp and the precursor gel of a solgel glass, with nominal composition in mol% CaO-26, SiO2-70, P205-4, has been prepared. The amounts of components used have been selected to obtain a final relationship for OHAp/solgel glass of 60/40 on heating. Two different thermal treatments have been used: (i) 700 degrees C, temperature of solgel glass stabilisation and (ii) 1000 degrees C, lower temperature of hydroxyapatite sintering. The bioactivity of the resulting materials has been examined in vitro by immersion in simulated body fluid at 37 degrees C. The results obtained show that both materials are bioactive. The apatite-like layer grown is greater for the new materials than for the OHAp and the solgel glass themselves. PMID:11950057

Ragel, C V; Vallet-Regí, M; Rodríguez-Lorenzo, L M

2002-04-01

140

Influence of strontium for calcium substitution in bioactive glasses on degradation, ion release and apatite formation  

PubMed Central

Bioactive glasses are able to bond to bone through the formation of hydroxy-carbonate apatite in body fluids while strontium (Sr)-releasing bioactive glasses are of interest for patients suffering from osteoporosis, as Sr was shown to increase bone formation both in vitro and in vivo. A melt-derived glass series (SiO2–P2O5–CaO–Na2O) with 0–100% of calcium (Ca) replaced by Sr on a molar base was prepared. pH change, ion release and apatite formation during immersion of glass powder in simulated body fluid and Tris buffer at 37°C over up to 8 h were investigated and showed that substituting Sr for Ca increased glass dissolution and ion release, an effect owing to an expansion of the glass network caused by the larger ionic radius of Sr ions compared with Ca. Sr release increased linearly with Sr substitution, and apatite formation was enhanced significantly in the fully Sr-substituted glass, which allowed for enhanced osteoblast attachment as well as proliferation and control of osteoblast and osteoclast activity as shown previously. Studying the composition–structure–property relationship in bioactive glasses enables us to successfully design next-generation biomaterials that combine the bone regenerative properties of bioactive glasses with the release of therapeutically active Sr ions.

Fredholm, Yann C.; Karpukhina, Natalia; Brauer, Delia S.; Jones, Julian R.; Law, Robert V.; Hill, Robert G.

2012-01-01

141

Capacity of mesoporous bioactive glass nanoparticles to deliver therapeutic molecules  

NASA Astrophysics Data System (ADS)

Inorganic bioactive nanomaterials are attractive for hard tissue regeneration, including nanocomponents for bone replacement composites and nanovehicles for delivering therapeutics. Bioactive glass nanoparticles (BGn) have recently gained potential usefulness as bone and tooth regeneratives. Here we demonstrate the capacity of the BGn with mesopores to load and deliver therapeutic molecules (drugs and particularly genes). Spherical BGn with sizes of 80-90 nm were produced to obtain 3-5 nm sized mesopores through a sono-reacted sol-gel process. A simulated body fluid test of the mesoporous BGn confirmed their excellent apatite forming ability and the cellular toxicity study demonstrated their good cell viability up to 100 ?g ml-1. Small molecules like chemical drug (Na-ampicillin) and gene (small interfering RNA; siRNA) were introduced as model drugs considering the mesopore size of the nanoparticles. Moreover, amine-functionalization allowed switchable surface charge property of the BGn (from -20-30 mV to +20-30 mV). Loading of ampicillin or siRNA saturated within a few hours (~2 h) and reflected the mesopore structure. While the ampicillin released relatively rapidly (~12 h), the siRNA continued to release up to 3 days with almost zero-order kinetics. The siRNA-nanoparticles were easily taken up by the cells, with a transfection efficiency as high as ~80%. The silencing effect of siRNA delivered from the BGn, as examined by using bcl-2 model gene, showed dramatic down-regulation (~15% of control), suggesting the potential use of BGn as a new class of nanovehicles for genes. This, in conjunction with other attractive properties, including size- and mesopore-related high surface area and pore volume, tunable surface chemistry, apatite-forming ability, good cell viability and the possible ion-related stimulatory effects, will potentiate the usefulness of the BGn in hard tissue regeneration.Inorganic bioactive nanomaterials are attractive for hard tissue regeneration, including nanocomponents for bone replacement composites and nanovehicles for delivering therapeutics. Bioactive glass nanoparticles (BGn) have recently gained potential usefulness as bone and tooth regeneratives. Here we demonstrate the capacity of the BGn with mesopores to load and deliver therapeutic molecules (drugs and particularly genes). Spherical BGn with sizes of 80-90 nm were produced to obtain 3-5 nm sized mesopores through a sono-reacted sol-gel process. A simulated body fluid test of the mesoporous BGn confirmed their excellent apatite forming ability and the cellular toxicity study demonstrated their good cell viability up to 100 ?g ml-1. Small molecules like chemical drug (Na-ampicillin) and gene (small interfering RNA; siRNA) were introduced as model drugs considering the mesopore size of the nanoparticles. Moreover, amine-functionalization allowed switchable surface charge property of the BGn (from -20-30 mV to +20-30 mV). Loading of ampicillin or siRNA saturated within a few hours (~2 h) and reflected the mesopore structure. While the ampicillin released relatively rapidly (~12 h), the siRNA continued to release up to 3 days with almost zero-order kinetics. The siRNA-nanoparticles were easily taken up by the cells, with a transfection efficiency as high as ~80%. The silencing effect of siRNA delivered from the BGn, as examined by using bcl-2 model gene, showed dramatic down-regulation (~15% of control), suggesting the potential use of BGn as a new class of nanovehicles for genes. This, in conjunction with other attractive properties, including size- and mesopore-related high surface area and pore volume, tunable surface chemistry, apatite-forming ability, good cell viability and the possible ion-related stimulatory effects, will potentiate the usefulness of the BGn in hard tissue regeneration. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr31775c

El-Fiqi, Ahmed; Kim, Tae-Hyun; Kim, Meeju; Eltohamy, Mohamed; Won, Jong-Eun; Lee, Eun-Jung; Kim, Hae-Won

2012-11-01

142

Borate Glass Supports the In Vitro Osteogenic Differentiation of Human Mesenchymal Stem Cells  

Microsoft Academic Search

Bioactive ceramics have the ability to bond to surrounding bone and potentially enhance bone in-growth. Silicate based bioactive glasses and glass-ceramics, such as 45S5 bioactive glass, have been widely investigated for bone repair or as scaffolds for cell-based bone tissue engineering. Recent data have demonstrated that silica-free borate glasses also exhibit bioactive behavior and have been shown to convert to

Nicholas W. Marion; Wen Liang; Gwendolen C. Reilly; Delbert E. Day; Mohamed N. Rahaman; Jeremy J. Mao

2005-01-01

143

Hydroxyapatite Formation on Sol-Gel Derived Poly(?-Caprolactone)/Bioactive Glass Hybrid Biomaterials.  

PubMed

Investigation of novel biomaterials for bone regeneration is based on the development of scaffolds that exhibit bone-bonding ability, biocompatibility, and sufficient mechanical strength. In this study, using novel poly (?-caprolactone)/bioactive glass (PCL/BG) hybrids with different organic/inorganic ratios, the effects of BG contents on the in vitro bone-like hydroxyapatite (HA) formation, mechanical properties, and biocompatibility were investigated. Rapid precipitation of HA on the PCL/BG hybrid surfaces were observed after incubating in simulated body fluid (SBF) for only 6 h, as confirmed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and inductively coupled plasma atomic emission spectroscopy (ICPS). The ICPS elemental analysis results were further analyzed in terms of the Ca(2+) and PO(4)(3-) which were consumed to form the apatite layer. The results revealed that the rate and total amount of HA deposition decreased with an increase in PCL content. The compressive modulus and strength of the PCL/BG hybrids increased with the decrease in PCL content. The highest values were achieved at the lowest PCL content (10 wt %) and were around, 90 MPa and 1.4 GPa, respectively. To evaluate the cytotoxicity of PCL/BG bioactive hybrids, MC3T3-E1 osteoblast-like cells were cultured for up to 72 h. Our data indicated that whereas initial cell attachment was marginally lower than the control tissue culture poly styrene (TCPS) surface, the hybrid materials promoted cell growth in a time-dependent manner. Cell viability within the different PCL/BG hybrid samples appeared to be influenced by compositional differences whereby higher PCL contents correlated with slight reduction in cell viability. Taken together, this study adds important new information to our knowledge on hydroxyapatite formation, mechanical properties, and cytotoxic effects of PCL/BG hybrids prepared by the sol-gel process using a tertiary glass composition and may have considerable potential for bone tissue regeneration applications. PMID:22625179

Allo, Bedilu A; Rizkalla, Amin S; Mequanint, Kibret

2012-06-01

144

Preparation and in vitro bioactivity of hydroxyapatite\\/solgel glass biphasic material  

Microsoft Academic Search

Hydroxyapatite\\/solgel glass biphasic material has been obtained in order to improve the bioactivity of the hydroxyapatite (OHAp). A mixture of stoichiometric OHAp and the precursor gel of a solgel glass, with nominal composition in mol% CaO-26, SiO2-70, P2O5-4, has been prepared. The amounts of components used have been selected to obtain a final relationship for OHAp\\/solgel glass of 60\\/40 on

C. V. Ragel; M. Vallet-Reg??; L. M. Rodr??guez-Lorenzo

2002-01-01

145

Effects of bioactive glass, hydroxyapatite and bioactive glass - Hydroxyapatite composite graft particles in the treatment of infrabony defects  

PubMed Central

Background: Several synthetic alloplastic materials have been used in the past as an implant in infrabony defects with a goal to reconstruct the lost part of attachment apparatus via new osseous tissue formation. The present study was undertaken to evaluate and compare clinico-radiographically, the effect of bioactive glass (BG), hydroxyapatite (HA), and BG-HA composite bone graft particles in the treatment of human infra-bony periodontal defects. Materials and Methods: Indigenous synthetic HA, BG, and BG-HA composite bone graft materials were developed in the laboratory. Twenty eight infrabony periodontal defects were equally distributed (i.e., seven defects) into four groups. The defects were treated separately with three types of graft materials and non-grafted manner (open flap debridement alone, control) to evaluate both the soft and hard tissue responses after six months of surgery. Evaluation was done by studying different parameters such as plaque index, gingival index, relative attachment level, probing pocket depth, and radiographic bone fill in Intra Oral Peri-Apical radiograph. Results: The healing of defects was uneventful and free of any biological complications. The gain in relative attachment level, reduction of probing pocket depth, and bone fill was statistically significant in all four groups. BG and BG-HA synthetic bone graft implanted sites showed significant bone fill (P<0.05) than hydroxyapatite and unimplanted control sites. Conclusion: The performance of BG and its composite was better compared to HA and open flap debridement alone for the reconstruction of infrabony defects. The BG-HA composite particles may effectively be used as an alternative bone graft material for infrabony defects.

Mistry, Surajit; Kundu, Debabrata; Datta, Someswar; Basu, Debabrata

2012-01-01

146

Adhesion of bioactive glass coating to Ti6Al4V oral implant  

Microsoft Academic Search

Bioactive glass (BAG) is a bioactive material with a high potential as implant material. Reactive plasma spraying produces an economically feasible BAG-coating for Ti6Al4V oral implants. This coating is only functional if it adheres well to the metal substrate and if it is strong enough to transfer all loads. To examine these two properties an appropriate mechanical adhesion test, the

J Schrooten; J. A Helsen

2000-01-01

147

Surface signatures of bioactivity: MD simulations of 45S and 65S silicate glasses.  

PubMed

The surface of a bioactive (45S) and a bioinactive (65S) glass composition has been modeled using shell-model classical molecular dynamics simulations. Direct comparison of the two structures allowed us to identify the potential role of specific surface features in the processes leading to integration of a bioglass implant with the host tissues, focusing in particular on the initial dissolution of the glass network. The simulations highlight the critical role of network fragmentation and sodium enrichment of the surface in determining the rapid hydrolysis and release of silica fragments in solution, characteristic of highly bioactive compositions. On the other hand, no correlation has been found between the surface density of small (two- and three-membered) rings and bioactivity, thus suggesting that additional factors need to be taken into account to fully understand the role of these sites in the mechanism leading to calcium phosphate deposition on the glass surface. PMID:19725567

Tilocca, Antonio; Cormack, Alastair N

2010-01-01

148

Examining porous bio-active glass as a potential osteo-odonto-keratoprosthetic skirt material.  

PubMed

Bio-active glass has been developed for use as a bone substitute with strong osteo-inductive capacity and the ability to form strong bonds with soft and hard tissue. The ability of this material to enhance tissue in-growth suggests its potential use as a substitute for the dental laminate of an osteo-odonto-keratoprosthesis. A preliminary in vitro investigation of porous bio-active glass as an OOKP skirt material was carried out. Porous glass structures were manufactured from bio-active glasses 1-98 and 28-04 containing varying oxide formulation (1-98, 28-04) and particle size range (250-315 ?m for 1-98 and 28-04a, 315-500 ?m for 28-04b). Dissolution of the porous glass structure and its effect on pH was measured. Structural 2D and 3D analysis of porous structures were performed. Cell culture experiments were carried out to study keratocyte adhesion and the inflammatory response induced by the porous glass materials. The dissolution results suggested that the porous structure made out of 1-98 dissolves faster than the structures made from glass 28-04. pH experiments showed that the dissolution of the porous glass increased the pH of the surrounding solution. The cell culture results showed that keratocytes adhered onto the surface of each of the porous glass structures, but cell adhesion and spreading was greatest for the 98a bio-glass. Cytokine production by all porous glass samples was similar to that of the negative control indicating that the glasses do not induce a cytokine driven inflammatory response. Cell culture results support the potential use of synthetic porous bio-glass as an OOKP skirt material in terms of limited inflammatory potential and capacity to induce and support tissue ingrowth. PMID:23386212

Huhtinen, Reeta; Sandeman, Susan; Rose, Susanna; Fok, Elsie; Howell, Carol; Fröberg, Linda; Moritz, Niko; Hupa, Leena; Lloyd, Andrew

2013-02-06

149

In vitro and in vivo release of cefuroxime axetil from bioactive glass as an implantable delivery system in experimental osteomyelitis  

Microsoft Academic Search

The aim of this study was to evaluate the characterisation, in vitro and in vivo biocompatibility and antimicrobial activity of bioactive glass (BG) impregnated with an antibiotic. The BG was prepared by normal glass melting procedures as a controlled release device to treat experimental osteomyelitis. The study design was for prospective in vivo experimental study. Two sets of porous bioactive

Samit K. Nandi; Biswanath Kundu; Prasenjit Mukherjee; Tapan K. Mandal; Someswar Datta; Dipak K. De; Debabrata Basu

2009-01-01

150

Macro-to-micro porous special bioactive glass and ceftriaxone–sulbactam composite drug delivery system for treatment of chronic osteomyelitis: an investigation through in vitro and in vivo animal trial  

Microsoft Academic Search

A systematic and extensive approach incorporating in vitro and in vivo experimentation to treat chronic osteomyelitis in animal\\u000a model were made using antibiotic loaded special bioactive glass porous scaffolds. After thorough characterization for porosity,\\u000a distribution, surface charge, a novel drug composite were infiltrated by using vacuum infiltration and freeze-drying method\\u000a which was subsequently analyzed by SEM–EDAX and studied for in

Biswanath Kundu; Samit Kumar Nandi; Sudip Dasgupta; Someswar Datta; Prasenjit Mukherjee; Subhasis Roy; Aruna Kumari Singh; Tapan Kumar Mandal; Partha Das; Rupnarayan Bhattacharya; Debabrata Basu

2011-01-01

151

pH-dependent antibacterial effects on oral microorganisms through pure PLGA implants and composites with nanosized bioactive glass.  

PubMed

Biomaterials made of biodegradable poly(?-hydroxyesters) such as poly(lactide-co-glycolide) (PLGA) are known to decrease the pH in the vicinity of the implants. Bioactive glass (BG) is being investigated as a counteracting agent buffering the acidic degradation products. However, in dentistry the question arises whether an antibacterial effect is rather obtained from pure PLGA or from BG/PLGA composites, as BG has been proved to be antimicrobial. In the present study the antimicrobial properties of electrospun PLGA and BG45S5/PLGA fibres were investigated using human oral bacteria (specified with mass spectrometry) incubated for up to 24h. BG45S5 nanoparticles were prepared by flame spray synthesis. The change in colony-forming units (CFU) of the bacteria was correlated with the pH of the medium during incubation. The morphology and structure of the scaffolds as well as the appearance of the bacteria were followed bymicroscopy. Additionally, we studied if the presence of BG45S5 had an influence on the degradation speed of the polymer. Finally, it turned out that the pH increase induced by the presence of BG45S5 in the scaffold did not last long enough to show a reduction in CFU. On the contrary, pure PLGA demonstrated antibacterial properties that should be taken into consideration when designing biomaterials for dental applications. PMID:23816650

Hild, Nora; Tawakoli, Pune N; Halter, Jonas G; Sauer, Bärbel; Buchalla, Wolfgang; Stark, Wendelin J; Mohn, Dirk

2013-06-29

152

Sintering behaviour of 45S5 bioactive glass.  

PubMed

In this study, we report on the effect of Bioglass structural transformations on its sintering behaviour. While heating up to 1000 degrees C, five successive transformations occur: glass transition, glass-in-glass phase separation, two crystallization processes and a second glass transition. The sintering of the material exhibits two main shrinkage stages associated with the two glass transitions at 550 and 850 degrees C. At 580 degrees C, the glass-in-glass phase separation induces a decrease in the sintering rate immediately followed by the major crystalline phase crystallization (Na(2)CaSi(2)O(6)) between 600 and 700 degrees C, from the surface to the bulk of the particles. A complete inhibition of sintering takes place followed by a minor shrinkage effect due to crystallization. A plateau is then observed until the second glass transition temperature is reached. A modification of Frenkel's model allows the determination of the glass-in-glass phase separation kinetics and the identification of the structural transformations effects on sintering behaviour. PMID:18583208

Lefebvre, L; Gremillard, L; Chevalier, J; Zenati, R; Bernache-Assolant, D

2008-06-05

153

Database of bioactive ring systems with calculated properties and its use in bioisosteric design and scaffold hopping.  

PubMed

A system for identification of bioisosteric scaffolds is presented. The system uses a database of over 7000 scaffolds extracted from bioactive molecules. Scaffolds in the database are characterized by their size, shape, pharmacophore features and several ADME descriptors. Also properties characterizing electron-donating or -accepting power at connection vectors are considered. All these features are used as search criteria to find scaffolds with the most similar properties to the query. To guarantee fast processing the search is performed using topological descriptors only, but the system may be used to find optimal replacements of scaffolds also directly in the protein binding site. In this case a set of 3D conformations for the best 2D hits is generated and analogs optimally fitting the binding pocket are identified by overlap with the query ligand and by optimizing interactions with the protein. This tool is used at Novartis as an idea generator for identification of novel non-classical bioisosteric analogs in the drug discovery process. PMID:22436390

Ertl, Peter

2012-03-03

154

Conversion of borate-based glass scaffold to hydroxyapatite in a dilute phosphate solution.  

PubMed

Porous scaffolds of a borate-based glass (composition in mol%: 6Na2O, 8K2O, 8MgO, 22CaO, 36B2O3, 18SiO2, 2P2O5), with interconnected porosity of approximately 70% and pores of size 200-500 microm, were prepared by a polymer foam replication technique. The degradation of the scaffolds and conversion to a hydroxyapatite-type material in a 0.02 M K2HPO4 solution (starting pH = 7.0) at 37 degrees C were studied by measuring the weight loss of the scaffolds, as well as the pH and the boron concentration of the solution. X-ray diffraction, scanning electronic microscopy and energy dispersive x-ray analysis showed that a hydroxyapatite-type material was formed on the glass surface within 7 days of immersion in the phosphate solution. Cellular response to the scaffolds was assessed using murine MLO-A5 cells, an osteogenic cell line. Scanning electron microscopy showed that the scaffolds supported cell attachment and proliferation during the 6 day incubation. The results indicate that this borate-based glass could provide a promising degradable scaffold material for bone tissue engineering applications. PMID:20057014

Liu, Xin; Pan, Haobo; Fu, Hailuo; Fu, Qiang; Rahaman, Mohamed N; Huang, Wenhai

2010-01-07

155

High phosphate content significantly increases apatite formation of fluoride-containing bioactive glasses.  

PubMed

Bioactive glass-containing toothpastes for treating dentine hypersensitivity work by precipitating hydroxycarbonate apatite (HCA) onto the tooth surface, but concerns exist over the long-term durability of HCA in the mouth. Fluoride-containing bioactive glasses form fluorapatite (FAp) in physiological solutions, which is more chemically stable against acid attack. The influence of phosphate content on apatite formation was investigated by producing a low-phosphate (about 1 mol% P(2)O(5)) and a high-phosphate (about 6 mol%) series of melt-derived bioactive glasses in the system SiO(2)P(2)O(5)CaONa(2)O; increasing amounts of CaF(2) were added by keeping the ratio of all other components constant. pH change, ion release and apatite formation during immersion in Tris buffer at 37°C over up to 7 days were investigated. Crystal phases formed in Tris buffer were characterized using infrared spectroscopy, X-ray diffraction and solid-state nuclear magnetic resonance (NMR) spectroscopy. An increase in phosphate or fluoride content allowed for apatite formation at lower pH; fluoride enhanced apatite formation due to lower solubility of FAp compared to hydroxyapatite or HCA. High phosphate content glasses formed apatite significantly faster (within 6h) than low phosphate content glasses (within 3 days). In addition, an increase in phosphate content favoured apatite formation rather than fluorite (CaF(2)). (19)F magic angle spinning NMR showed the apatite formed by fluoride-containing glasses to be FAp, which makes these glasses of particular interest for dental applications. This study shows that by varying the phosphate content, the reactivity and apatite formation of bioactive glasses can be controlled successfully. PMID:21115144

Mneimne, Mohammed; Hill, Robert G; Bushby, Andrew J; Brauer, Delia S

2010-11-27

156

In vitro and in vivo evaluations of nano-hydroxyapatite/polyamide 66/glass fibre (n-HA/PA66/GF) as a novel bioactive bone screw.  

PubMed

In this study, we prepared nano-hydroxyapatite/polyamide 66/glass fibre (n-HA/PA66/GF) bioactive bone screws. The microstructure, morphology and coating of the screws were characterised, and the adhesion, proliferation and viability of MC3T3-E1 cells on n-HA/PA66/GF scaffolds were determined using scanning electron microscope, CCK-8 assays and cellular immunofluorescence analysis. The results confirmed that n-HA/PA66/GF scaffolds were biocompatible and had no negative effect on MC3T3-E1 cells in vitro. To investigate the in vivo biocompatibility, internal fixation properties and osteogenesis of the bioactive screws, both n-HA/PA66/GF screws and metallic screws were used to repair intercondylar femur fractures in dogs. General photography, CT examination, micro-CT examination, histological staining and biomechanical assays were performed at 4, 8, 12 and 24 weeks after operation. The n-HA/PA66/GF screws exhibited good biocompatibility, high mechanical strength and extensive osteogenesis in the host bone. Moreover, 24 weeks after implantation, the maximum push-out load of the bioactive screws was greater than that of the metallic screws. As shown by their good cytocompatibility, excellent biomechanical strength and fast formation and ingrowth of new bone, n-HA/PA66/GF screws are thus suitable for orthopaedic clinical applications. PMID:23861888

Su, Bao; Peng, Xiaohua; Jiang, Dianming; Wu, Jun; Qiao, Bo; Li, Weichao; Qi, Xiaotong

2013-07-08

157

Enhancement of cells proliferation and control of bioactivity of strontium doped glass  

NASA Astrophysics Data System (ADS)

Bioactivity and chemical reactivity of bioactive glass offer the ability to bond for soft and hard biological tissues. In this work, synthesis was carried out by using melting and rapid quenching. Strontium was introduced as trace element at different contents in the glass matrix, according to its concentration in the bone matrix. This chemical element presents a high interest in the bone metabolism activity. Investigations were conducted on the surface of biomaterials by using in vitro assay after immersion in SBF. Several physico-chemical methods such as SEM, FTIR, NMR, ICP-OES and MTT test were employed to highlight the effects of the Sr. The in vitro experiments showed that after soaking in SBF, the behaviour of pure glass is different compared to glass doped with Sr. NMR analyses showed in the 29Si MAS-NMR that glass matrix undergoes some changes after in vitro assays particularly the emergence of new components attributed to Q 3(OH). The presence of Sr slowed down the bioactivity of glass after immersion in SBF. The non toxic character of compounds was confirmed. Introduction of Sr at 0.1 wt % induce an enhancement of cells at about 14.3%.

Oudadesse, H.; Dietrich, E.; Bui, X. V.; Le Gal, Y.; Pellen, P.; Cathelineau, G.

2011-08-01

158

Bioactivity of thermal plasma synthesized bovine hydroxyapatite/glass ceramic composites  

NASA Astrophysics Data System (ADS)

Bone injuries and failures often require the inception of implant biomaterials. Research in this area is receiving increasing attention worldwide. A variety of artificial bone materials, such as metals, polymeric materials, composites and ceramics, are being explored to replace diseased bones. Calcium phosphate ceramics are currently used as biomaterials for many applications in both dentistry and orthopedics. Bioactive silicate-based glasses show a higher bioactive behaviour than calcium phosphate materials. It is very interesting to study the mixtures of HA and silicate-based glasses. In the present study; natural bovine hydroxyapatite / SiO2-CaO-MgO glass composites were produced using the Transferred arc plasma (TAP) melting method. TAP melting route is a brisk process of preparation of glass-ceramics in which the raw materials are melted in the plasma and crystallization of the melt occurs while cooling down at a much faster rate in relatively short processing times compared to the conventional methods of manufacture of glass ceramics/composites. It is well known that; one essential step to the understanding of the biological events occurring at the bone tissue/material interface is the biological investigation by in vitro tests. Cell lines are commonly used for biocompatibility tests, and are very efficient because of their reproducibility and culture facility. In this study, we report the results of a study on the response of primary cultures of human fibroblast cells to TAP melted bioactive glass ceramics.

Yoganand, C. P.; Selvarajan, V.; Rouabhia, Mahmoud; Cannillo, Valeria; Sola, Antonella

2010-02-01

159

TiO2-Bioactive Glass Nanostructure Composite Films Produced by a Sol-Gel Method: In Vitro Behavior and UV-Enhanced Bioactivity  

NASA Astrophysics Data System (ADS)

The aim of this study is to develop TiO2, titania, -based composite films for 316 stainless steel substrate and to improve their apatite-forming activity. A series of sol-gel derived bioactive glass (49S) and bioactive glass (49S)-TiO2 films were deposited on the 316L stainless steel substrates by the spin-coating method. Amorphous bioactive glass (49S) film and polycrystalline titania-bioactive glass composite films were obtained after annealing the deposited layers at 600 °C. The microstructure and in vitro bioactivity of the composite films as well as the effect of titania nanopowder content and ultra violet (UV) irradiation on the in vitro bioactivity were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). While bioactivity tests are often carried out within 28-day periods, SEM and EDS data show that, after soaking in SBF for just 7 days, the prepared composite surfaces are covered with an apatite layer. The grown apatite layer consists of spherulites formed by nanosized needle-like aggregates. Fourier transform infrared spectroscopy investigations confirm apatite formation and suggest that the formed apatite is carbonated.

Omid-Bakhtiari, Marzie; Nasr-Esfahani, Mojtaba; Nourmohamadi, Abolghasem

2013-08-01

160

Influence of bioactive glass on changes in alveolar process dimensions after exodontia  

Microsoft Academic Search

Background: Preservation of the alveolar process after tooth extraction is desirable because it facilitates placement of endosseous implants and minimizes adverse esthetic results associated with fixed partial dentures. The purpose of this study was to evaluate the clinical effectiveness of bioactive glass used as a graft material combined with calcium sulfate used in the form of a mechanical barrier in

Paulo M Camargo; Vojislav Lekovic; Michael Weinlaender; Perry R Klokkevold; E. Barrie Kenney; Bozidar Dimitrijevic; Melica Nedic; Sacha Jancovic; Marco Orsini

2000-01-01

161

Bioactive and bioresorbable cellular cubic-composite scaffolds for use in bone reconstruction  

PubMed Central

We used a novel composite fibre-precipitation method to create bioactive and bioresorbable cellular cubic composites containing calcium phosphate (CaP) particles (unsintered and uncalcined hydroxyapatite (u-HA), ?-tricalcium phosphate, ?-tricalcium phosphate, tetracalcium phosphate, dicalcium phosphate dihydrate, dicalcium phosphate anhydrate or octacalcium phosphate) in a poly-d/l-lactide matrix. The CaP particles occupied greater than or equal to 70?wt% (greater than or equal to 50?vol%) fractions within the composites. The porosities of the cellular cubic composites were greater than or equal to 70% and interconnective pores accounted for greater than or equal to 70% of these values. In vitro changes in the cellular geometries and physical properties of the composites were evaluated over time. The Alamar Blue assay was used to measure osteoblast proliferation, while the alkaline phosphatase assay was used to measure osteoblast differentiation. Cellular cubic C-u-HA70, which contained 70?wt% u-HA particles in a 30?wt% poly-d/l-lactide matrix, showed the greatest three-dimensional cell affinity among the materials tested. This composite had similar compressive strength and cellular geometry to cancellous bone, could be modified intraoperatively (by trimming or heating) and was able to form cortico-cancellous bone-like hybrids. The osteoinductivity of C-u-HA70, independent of biological growth factors, was confirmed by implantation into the back muscles of beagles. Our results demonstrated that C-u-HA70 has the potential as a cell scaffold or temporary hard-tissue substitute for clinical use in bone reconstruction.

Shikinami, Yasuo; Okazaki, Kenshi; Saito, Makoto; Okuno, Masaki; Hasegawa, Shin; Tamura, Jiro; Fujibayashi, Shunsuke; Nakamura, Takashi

2006-01-01

162

Glass–ceramic scaffolds containing silica mesophases for bone grafting and drug delivery  

Microsoft Academic Search

Glass–ceramic macroporous scaffolds were prepared using glass powders and polyethylene (PE) particles of two different sizes.\\u000a The starting glass, named as Fa-GC, belongs to the system SiO2–P2O5–CaO–MgO–Na2O–K2O–CaF2 and was synthesized by a traditional melting-quenching route. The glass was ground and sieved to obtain powders of specific\\u000a size which were mixed with PE particles and then uniaxially pressed in order to

Chiara Vitale-Brovarone; Francesco Baino; Marta Miola; Renato Mortera; Barbara Onida; Enrica Verné

2009-01-01

163

Sintering temperature effects on the in vitro bioactive response of tape cast and sintered bioactive glass-ceramic in Tris buffer.  

PubMed

Tape casting procedures were used to form thin polymeric sheets (100 microm thickness) loaded with bioactive glass particulate. Blanks were punched from the sheets, stacked, laminated, and heated in air to 500 degrees C to remove the organic phase. The resulting bioactive glass discs were sintered at 800 degrees C, 900 degrees C, or 1000 degrees C. Because the material is built up in layers and can be machined in the green state, such a processing technique can be used to form complex-shaped materials. The in vitro bioactivity of the tape cast sintered (TCS) bioactive glass-ceramic discs was then assessed in Tris buffer. The sample surface area to volume buffer (SA/V) ratio was approximately 0.1 cm(2)/mL. Tape cast bioactive glass-ceramic sintered at 900 degrees C and 1000 degrees C formed crystalline hydroxyapatite layers after 24 h in Tris buffer as indicated by FTIR, SEM, and EDS analysis. Decreasing the SA/V ratio to 0.013 cm(2)/mL allowed for the formation of crystalline hydroxyapatite layers on the surface of 800C TCS bioactive glass-ceramic. Given the dependence of the bioactive response as a function of the processing schedule and SA/V ratio, it may be possible to tailor the response to that desired in vivo or in vitro for tissue engineering studies. Biaxial flexural strength of TCS bioactive glass-ceramic increased with increasing sintering temperature. Strength of samples sintered at 1000 degrees C for 3 h increased from 87 to 120 MPa after 2 weeks' immersion in Tris buffer. PMID:11553883

Clupper, D C; Mecholsky, J J; LaTorre, G P; Greenspan, D C

2001-12-15

164

Bioactive glass coatings with hydroxyapatite and Bioglass (registered) particles on Ti-based implants. 1. Processing  

SciTech Connect

Silicate-based glasses with thermal expansion coefficients that match those of Ti6Al4V were prepared and used to coat Ti6Al4V by a simple enameling technique. Bioglass (BG) (registered) or hydroxyapatite (HA) particles were embedded on the coatings in order to enhance their bioactivity. HA particles were partially embedded during heating and remained firmly embedded on the coating after cooling. There was no apparent reaction at the glass/HA interface at the temperatures used in this work (800-840 degrees C). In contrast, BG particles softened and some infiltration into the glass coating took place during heat treatment. In this case, particles with sizes over 45 (mu)m were required, otherwise the particles became hollow due to the infiltration and crystallization of the glass surface. The concentration of the particles on the coating was limited to 20% of surface coverage. Concentrations above this value resulted in cracked coatings due to excessive induced stress. Cracks did not prop agate along the interfaces when coatings were subjected to Vickers indentation tests, indicating that the particle/glass and glass/metal interfaces exhibited strong bonds. Enameling, producing excellent glass/metal adhesion with well-attached bioactive particles on the surface, is a promising method of forming reliable and lasting implants which can endure substantial chemical and mechanical stresses.

Gomez-Vega, J.M.; Saiz, E.; Tomsia, A.P.; Marshall, G.W.; Marshall, S.J.

1999-06-01

165

Study of hydroxyl carbonate apatite formation on bioactive glass coated dental ceramics by confocal laser scanning microscopy (CLSM)  

NASA Astrophysics Data System (ADS)

Some dental ceramics were coated with a bioactive glass and resulted the formation of a stable and well bonded with the ceramic substrate thin layer. After immersion in a solution with ion concentrations similar to those of human blood plasma the development of hydroxy carbonate apatite layer on the surface of bioactive glass may be observed. The objective of this study was to investigate structural surface changes of bioactive glass, after exposure in a simulated body fluid for a different number of days. The roughness and topography of the hydroxyapatite surface were investigated by Confocal Scanning Laser Microscopy. The chemical composition was analyzed by Energy Dispersive Spectroscopy measurements.

Stanciu, G. A.; Savu, B.; Sandulescu, I.; Paraskevopoulos, K.; Koidis, P.

2007-04-01

166

The effect of controlled release of PDGF-BB from heparin-conjugated electrospun PCL/gelatin scaffolds on cellular bioactivity and infiltration  

PubMed Central

Heparin-conjugated electrospun poly(?-caprolactone) (PCL)/gelatin scaffolds were developed to provide controlled release of platelet-derived growth factor-BB (PDGF-BB) and allow prolonged bioactivity of this molecule. A mixture of PCL and gelatin was electrospun into three different morphologies. Next, heparin molecules were conjugated to the reactive surface of the scaffolds. This heparin-conjugated scaffold allowed the immobilization of PDGF-BB via electrostatic interaction. In vitro PDGF-BB release profiles indicated that passive physical adsorption of PDGF-BB to non-heparinized scaffolds resulted in an initial burst release of PDGF-BB within 5 days, which then leveled off. However, electrostatic interaction between PDGF-BB and the heparin-conjugated scaffolds gave rise to a sustained release of PDGF-BB over the course of 20 days without an initial burst. Moreover, PDGF-BB that was strongly bound to the heparin-conjugated scaffolds enhanced smooth muscle cell (SMC) proliferation. In addition, scaffolds composed of 3.0 µm diameter fibers that were immobilized with PDGF-BB accelerated SMC infiltration into the scaffold when compared to scaffolds composed of smaller diameter fibers or scaffolds that did not release PDGF-BB. We concluded that the combination of the large pore structure in the scaffolds and the heparin-mediated delivery of PDGF-BB provided the most effective cellular interactions through synergistic physical and chemical cues.

Lee, Jongman; Yoo, James J.; Atala, Anthony; Lee, Sang Jin

2013-01-01

167

Enhancing the bioactivity of Poly(lactic-co-glycolic acid) scaffold with a nano-hydroxyapatite coating for the treatment of segmental bone defect in a rabbit model  

PubMed Central

Purpose Poly(lactic-co-glycolic acid) (PLGA) is excellent as a scaffolding matrix due to feasibility of processing and tunable biodegradability, yet the virgin scaffolds lack osteoconduction and osteoinduction. In this study, nano-hydroxyapatite (nHA) was coated on the interior surfaces of PLGA scaffolds in order to facilitate in vivo bone defect restoration using biomimetic ceramics while keeping the polyester skeleton of the scaffolds. Methods PLGA porous scaffolds were prepared and surface modification was carried out by incubation in modified simulated body fluids. The nHA coated PLGA scaffolds were compared to the virgin PLGA scaffolds both in vitro and in vivo. Viability and proliferation rate of bone marrow stromal cells of rabbits were examined. The constructs of scaffolds and autogenous bone marrow stromal cells were implanted into the segmental bone defect in the rabbit model, and the bone regeneration effects were observed. Results In contrast to the relative smooth pore surface of the virgin PLGA scaffold, a biomimetic hierarchical nanostructure was found on the surface of the interior pores of the nHA coated PLGA scaffolds by scanning electron microscopy. Both the viability and proliferation rate of the cells seeded in nHA coated PLGA scaffolds were higher than those in PLGA scaffolds. For bone defect repairing, the radius defects had, after 12 weeks implantation of nHA coated PLGA scaffolds, completely recuperated with significantly better bone formation than in the group of virgin PLGA scaffolds, as shown by X-ray, Micro-computerized tomography and histological examinations. Conclusion nHA coating on the interior pore surfaces can significantly improve the bioactivity of PLGA porous scaffolds.

Wang, De-Xin; He, Yao; Bi, Long; Qu, Ze-Hua; Zou, Ji-Wei; Pan, Zhen; Fan, Jun-Jun; Chen, Liang; Dong, Xin; Liu, Xiang-Nan; Pei, Guo-Xian; Ding, Jian-Dong

2013-01-01

168

Biological performance of boron-modified bioactive glass particles implanted in rat tibia bone marrow.  

PubMed

The aim of the present study was to characterize the neoformed bone tissue around boron-modified bioactive glass particles implanted in rat tibia bone marrow by histologic, histomorphometric and microchemical evaluation. Melt-derived glasses were prepared from a base 45S5 bioactive glass of nominal composition (45% SiO(2), 24.5% CaO, 24.5% Na(2)O and 6% P(2)O(5) in wt%). The glass composition was modified by adding 2% wt of boron oxide (45S5.2B). Histological and histomorphometric analyses using undecalcified sections showed that at 15 days post-implantation the area of neoformed bone tissue around the 45S5.2B particles was significantly higher than control 45S5 glass. No statistically significant differences were observed at 30 days post-implantation. The thickness of osseointegrated tissue on 45S5.2B BG particles was significantly greater than on the control at all experimental time-points evaluated. A statistically significant increase in the Ca:P ratio was observed in the neoformed bone around 45S5.2B particles 15 days post-implantation. The results of the present study provide evidence that particles of boron-modified 45S5 BG (45S5.2B) enhance bone formation more than 45S5 glass when implanted into the intramedullary canal of rat tibiae. PMID:18458389

Gorustovich, Alejandro A; López, José M Porto; Guglielmotti, María B; Cabrini, Rómulo L

2006-06-05

169

Gallium-containing phosphosilicate glasses: functionalization and in-vitro bioactivity.  

PubMed

A gallium containing glass 45.7SiO2·24.1Na2O·26.6CaO·2.6P2O5·1.0Ga2O3 (referred to as "Ga1.0") and a parent Ga-free glass 46.2SiO2·24.3Na2O·26.9CaO·2.6P2O5 (hereinafter represented as "H"), corresponding to Bioglass® 45S5, were functionalized with Tetraethoxysilane (TEOS) and (3-Aminopropyl)triethoxysilane (APTS) in order to improve their ability to bond with biomolecules, such as drugs, proteins, and peptides. Functionalization with TEOS and APTS promoted the increment in OH groups and formation of NH2 groups on the glass surface, respectively. The presence of OH or NH2 groups was investigated by means of IR spectroscopy and elemental analysis. Moreover, in vitro study of these functionalized glasses was performed in simulated body fluid (SBF) so as to investigate the effect of functionalization on the bioactive behavior of H and Ga1.0. The results showed that the functionalization was obtained along with maintaining their bioactivity. The surfaces of both functionalized glasses were covered by a layer of apatite within 30 days of SBF immersion. In addition, CaCO3 was also identified on the surface of APTS functionalized glasses. However, no gallium release was detected during SBF soaking. PMID:23706200

Lusvardi, Gigliola; Malavasi, Gianluca; Menabue, Ledi; Shruti, Shruti

2013-04-06

170

Cytotoxicity of zinc-containing bioactive glasses in contact with human osteoblasts.  

PubMed

Bioactive glasses such as Hench's 45S5 have applications to tissue engineering and bone repair: the insertion of zinc has been proposed to improve their bone-bonding ability and to slacken their dissolution in extracellular body fluids. In view of a potential clinical application, we have investigated whether zinc-containing 45S5 (HZ) glasses might be cytotoxic for human MG-63 osteoblasts. In our experimental conditions, after 24h of incubation HZ glasses released significant amounts of Zn(2+) and induced in MG-63 cells release of lactate dehydrogenase (index of cytotoxicity) and the following indexes of oxidative stress: (i) accumulation of intracellular malonyldialdehyde, (ii) increased activity of pentose phosphate pathway, (iii) increased expression of heme oxygenase-1, (iv) increased activity of Cu,Zn-superoxide dismutase, (v) decreased level of intracellular thiols. These effects were inversely related to the zinc content of glass powders, were mimicked by ZnCl(2) solutions and were prevented by either metal chelators (EDTA, NTA) or the antioxidant ascorbate, suggesting that Zn(2+) released fastly from HZ glasses can cause MG-63 cell damage via an oxidative stress. This work highlights the importance of designing Zn-containing bioactive glasses without cytotoxic effects and gives supplementary information about the prooxidant role of zinc in living systems. PMID:17399695

Aina, Valentina; Perardi, Alessandra; Bergandi, Loredana; Malavasi, Gianluca; Menabue, Ledi; Morterra, Claudio; Ghigo, Dario

2007-03-12

171

Multilayer bioactive glass/zirconium titanate thin films in bone tissue engineering and regenerative dentistry  

PubMed Central

Surface modification, particularly coatings deposition, is beneficial to tissue-engineering applications. In this work, bioactive glass/zirconium titanate composite thin films were prepared by a sol-gel spin-coating method. The surface features of the coatings were studied by scanning electron microscopy, atomic force microscopy, and spectroscopic reflection analyses. The results show that uniform and sound multilayer thin films were successfully prepared through the optimization of the process variables and the application of carboxymethyl cellulose as a dispersing agent. Also, it was found that the thickness and roughness of the multilayer coatings increase nonlinearly with increasing the number of the layers. This new class of nanocomposite coatings, comprising the bioactive and inert components, is expected not only to enhance bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion.

Mozafari, Masoud; Salahinejad, Erfan; Shabafrooz, Vahid; Yazdimamaghani, Mostafa; Vashaee, Daryoosh; Tayebi, Lobat

2013-01-01

172

Bioactivity in glass/PMMA composites used as drug delivery system.  

PubMed

Gentamicin sulfate has been incorporated in composites prepared from a SiO2-CaO-P2O5 bioactive glass and polymethylmethacrylate. Data showed that these materials could be used as drug delivery system, keeping the bioactive behavior of the glass. The composites supply high doses of the antibiotic during the first hours when they are soaked in simulated body fluid (SBF). Thereafter, a slower drug release is produced, supplying 'maintenance' doses until the end of the experiment. The gentamicin release rate is related with the ionic Ca2+ and H3O+ exchange between composite and SBF. The porous structure of the composites allows the growth of hydroxycarbonate apatite on the surface and into the pores. PMID:11246964

Arcos, D; Ragel, C V; Vallet-Regí, M

2001-04-01

173

Combining technologies to create bioactive hybrid scaffolds for bone tissue engineering  

PubMed Central

Combining technologies to engineer scaffolds that can offer physical and chemical cues to cells is an attractive approach in tissue engineering and regenerative medicine. In this study, we have fabricated polymer-ceramic hybrid scaffolds for bone regeneration by combining rapid prototyping (RP), electrospinning (ESP) and a biomimetic coating method in order to provide mechanical support and a physico-chemical environment mimicking both the organic and inorganic phases of bone extracellular matrix (ECM). Poly(ethylene oxide terephthalate)-poly(buthylene terephthalate) (PEOT/PBT) block copolymer was used to produce three dimensional scaffolds by combining 3D fiber (3DF) deposition, and ESP, and these constructs were then coated with a Ca-P layer in a simulated physiological solution. Scaffold morphology and composition were studied using scanning electron microscopy (SEM) coupled to energy dispersive X-ray analyzer (EDX) and Fourier Tranform Infrared Spectroscopy (FTIR). Bone marrow derived human mesenchymal stromal cells (hMSCs) were cultured on coated and uncoated 3DF and 3DF + ESP scaffolds for up to 21 d in basic and mineralization medium and cell attachment, proliferation, and expression of genes related to osteogenesis were assessed. Cells attached, proliferated and secreted ECM on all the scaffolds. There were no significant differences in metabolic activity among the different groups on days 7 and 21. Coated 3DF scaffolds showed a significantly higher DNA amount in basic medium at 21 d compared with the coated 3DF + ESP scaffolds, whereas in mineralization medium, the presence of coating in 3DF+ESP scaffolds led to a significant decrease in the amount of DNA. An effect of combining different scaffolding technologies and material types on expression of a number of osteogenic markers (cbfa1, BMP-2, OP, OC and ON) was observed, suggesting the potential use of this approach in bone tissue engineering.

Nandakumar, Anandkumar; Barradas, Ana; de Boer, Jan; Moroni, Lorenzo; van Blitterswijk, Clemens; Habibovic, Pamela

2013-01-01

174

3D printing of bone substitute implants using calcium phosphate and bioactive glasses  

Microsoft Academic Search

Customized implants for bone replacement are a great help for a surgeon to remodel maxillofacial or craniofacial defects in an esthetical way, and to significantly reduce operation times. The hypothesis of this study was that a composite of ?-tricalcium phosphate (?-TCP) and a bioactive glass similar to the 45S5 Henchglass® is suitable to manufacture customized implants via 3D-printing process. The

Christian Bergmann; Markus Lindner; Wen Zhang; Karolina Koczur; Armin Kirsten; Rainer Telle; Horst Fischer

2010-01-01

175

Bioactive Glass-Ceramic Coatings Synthesized by the Liquid Precursor Plasma Spraying Process  

Microsoft Academic Search

In this study, the liquid precursor plasma spraying process was used to manufacture P2O5-Na2O-CaO-SiO2 bioactive glass-ceramic coatings (BGCCs), where sol and suspension were used as feedstocks for plasma spraying. The effect\\u000a of precursor and spray parameters on the formation and crystallinity of BGCCs was systematically studied. The results indicated\\u000a that coatings with higher crystallinity were obtained using the sol precursor,

Yanfeng Xiao; Lei Song; Xiaoguang Liu; Yi Huang; Tao Huang; Jiyong Chen; Yao Wu; Fang Wu

2011-01-01

176

Light-sensitive intelligent drug delivery systems of coumarin-modified mesoporous bioactive glass  

Microsoft Academic Search

Functionalized mesoporous bioactive glasses (MBG) with photoactive coumarin demonstrates photo-responsive dimerization resulting in reversible gate operation. Coumarin-modified MBG was used as a drug delivery carrier to investigate drug storage\\/release characteristics using phenanthrene as a model drug. Irradiation with UV light (>310nm) induced photo-dimerization of the coumarin-modified MBG, which led to the pores’ closing with cyclobutane dimers and trapping of the

H.-M. Lin; W.-K. Wang; P.-A. Hsiung; S.-G. Shyu

2010-01-01

177

Use of a bioactive scaffold for the repair of bone defects in a novel reproducible vertebral body defect model.  

PubMed

Bone defects in vertebral bodies (VB) usually occur after the reduction of fractures or are caused by bone disease. Besides the treatment of original disease, repair of the bone defect can restore the structure of VB and improve stabilization of the spine to protect the spinal cord nerves. To aid studies of the efficacy of bioengineering techniques for repair of VB, we developed a rat model with a critical size bone defect in VB. Air-motivated burrs were used to create two sizes of bone defect (2 x 3 x 1.5 mm; 2 x 3 x 3 mm) in the anterior part of VB in 6-month-old Fischer 344 rats. Quantitative CT analyses and histological assays demonstrated that neither defects self-repaired by 8 weeks post surgery. Moreover, the tendency of bone formation was monitored in the same animal by serial CT image evaluations, allowing us to demonstrate that there was significant bone growth during the 4- to 6-week period after the creation of the bone defect. We then implanted sintered poly(lactic-co-glycolic acid) (PLGA) microsphere scaffolds loaded with Matrigel with or without recombinant human bone morphogenetic protein 2 (rhBMP2; 2.0 microg rhBMP2/10 microL Matrigel/scaffold) into the bone defect (2 x 3 x 3 mm) in the VB. Bone formation was detected by quantitative analyses of serial CT images, which demonstrated bone growth in rats that received the rhBMP2 implant, in both surrounding areas and inside area of the scaffold. In addition to a rapid increase within 2 weeks of the operation, another significant bone formation period was found between 4 and 8 weeks after the implantation. By contrast, the control group that received the implant without rhBMP2 did not show similar bone formation tendencies. The results of CT analyses were confirmed by histological studies. This study suggests that a critical size bone defect of the anterior VB can be developed in a rat model. Characterization of this model demonstrated that 4 to 6 weeks after creation of the defect was a significant bone growth period for VB bone repair in rats. This animal model has further utility for the study of different biomaterials for VB bone repair. Implantation of a bioactive PLGA scaffold carrying rhBMP2 allowed more successful repair of the VB defect. Although further characterization studies are needed, the bioactive PLGA scaffold developed in this study will likely adapt easily to other in vivo osteogenesis applications. PMID:20580872

Liang, Haixiang; Wang, Kun; Shimer, Adam L; Li, Xudong; Balian, Gary; Shen, Francis H

2010-05-24

178

In vitro bioactivity and gentamicin release from glass-polymer-antibiotic composites.  

PubMed

Composite materials have been prepared from bioactive glass powders in the SiO(2)-CaO-P(2)O(5) system, a biodegradable polymer [poly(L-lactic acid) (PLA)], a biostable polymer [polymethylmethacrylate (PMMA)], and an antibiotic [gentamicin]. The purpose of such composites is to obtain implantable materials that are able to lead to bone growth and also can, at the most critical inflammation-infection step, release an antibiotic. X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, and FTIR analyses after different soaking periods in SBF demonstrated the growth of an apatite-like layer on the composite surface. Therefore the bioactive glass-polymer-antibiotic combination used in this work does not inhibit the glass bioactivity. The release of gentamicin after a soaking of the materials in SBF was followed by UV-visible spectroscopy. A fast initial release during the first 10 h of soaking, followed by a controlled release of the drug was observed. PMID:10880085

Ragel, C V; Vallet-Regí, M

2000-09-01

179

Crystal growth on bioactive glass sputter-coated alumina in artificial saliva.  

PubMed

In this work, a bioactive glass was deposited on the alumina disk specimens by radio-frequency magnetron sputtering to study crystal formation ability in artificial saliva. Bioactive glass-coated specimens were immersed in artificial saliva for 1 week and 6 months. The specimens were observed with a scanning electron microscope (SEM) and the composition was determined by energy dispersive spectroscopy (EDS). The crystals that formed on the specimens were analyzed by Raman spectroscopic analysis and Micro-X-ray diffraction. SEM photomicrographs showed the formation of needle-like structures after immersion for 1 week, and tabular structures formed on the surface of the specimen for 6 months. EDS showed that both the needle-like and tabular structures were enriched with Ca and P. Raman and Micro-XRD spectra for the tabular structure showed peaks that may correspond to calcium phosphate. Thus, when immersed in artificial saliva, bioactive glass-coated alumina produced a crystal which might be calcium phosphate. PMID:24088833

Iijima, Masahiro; Hashimoto, Masanori; Kohda, Naohisa; Nakagaki, Susumu; Muguruma, Takeshi; Endo, Kazuhiko; Mizoguchi, Itaru

2013-01-01

180

Sequential identification of a degradable phosphate glass scaffold for skeletal muscle regeneration.  

PubMed

Tissue engineering has the potential to overcome limitations associated with current management of skeletal muscle defects. This study aimed to sequentially identify a degradable phosphate glass scaffold for the restoration of muscle defects. A series of glass compositions were investigated for the potential to promote bacterial growth. Thereafter, the response of human craniofacial muscle-derived cells was determined. Glass compositions containing Fe4- and 5?mol% did not promote greater Staphylococcus aureus and Staphylococcus epidermidis growth compared to the control (p?>?0.05). Following confirmation of myogenicity, further studies assessed the biocompatibility of glasses containing Fe5 mol%. Cells seeded on collagen-coated disks demonstrated comparable cellular metabolic activity to control. Upregulation of genes encoding for myogenic regulatory factors (MRFs) confirmed myofibre formation and there was expression of developmental MYH genes. The use of 3-D aligned fibre scaffolds supported unidirectional cell alignment and upregulation of MRF and developmental MYH genes. Compared to the 2-D disks, there was also expression of MYH2 and MYH7 genes, indicating further myofibre maturation on the 3-D scaffolds and confirming the importance of key biophysical cues. Copyright © 2012 John Wiley & Sons, Ltd. PMID:23086759

Shah, Rishma; Ready, Derren; Knowles, Jonathan C; Hunt, Nigel P; Lewis, Mark P

2012-10-22

181

Mineralization of dentin induced by treatment with bioactive glass S53P4 in vitro.  

PubMed

Dentin hypersensitivity can be managed to occlude dentin tubules, but none of the agents used are components of natural dentin. Using a calcium phosphate precipitation (CPP) method, dentin tubules can be occluded with a calcium phosphate (CaP) layer similar to the major inorganic component of dentin. The CPP method utilizes acidic pH conditions, such as etching of dentin, over the course of several dental treatments. A gentler method can be used to produce a CaP layer on the surface of dentin. By treating with bioactive glass S53P4 (BAG), or regular commercial glass (CG), mineralization occurs in physiologically neutral solutions such as simulated body fluid (SBF) and remineralization solution (RMS). After a short period of immersion, silica is dissolved from both types of glass, but the amount of silica released is much greater from BAG than from CG. The dissolved silica is adsorbed on the surface of dentin during the pretreatment procedure and enhances the mineralization of dentin in SBF. After 14 days' mineralization the dentin is fully covered by the CaP layer, but after 14 days' immersion in RMS decalcification of the dentin occurs. Pretreatment with BAG decreases the degree of decalcification of dentin during the mineralization process. These findings suggest that bioactive glass S53P4 can be used as a therapeutic material for mineralization of dentin and its tubules in a physiological environment. PMID:15124778

Forsback, Ari-Pekka; Areva, Sami; Salonen, Jukka I

2004-02-01

182

A multilayer approach to fabricate bioactive glass coatings on Ti alloys  

SciTech Connect

Glasses in the system Si-Ca-Na-Mg-P-K-O with thermal expansion coefficients close to that of Ti6Al4V were used to coat the titanium alloy by a simple enameling technique. Firings were done in air at temperatures between 800 and 840 C and times up to 1 minute. Graded compositions were obtained by firing multilayered glass coatings. Hydroxyapatite (HA) particles were mixed with the glass powder and the mixture was placed on the outer surface of the coatings to render them more bioactive. Coatings with excellent adhesion to the substrate and able to form apatite when immersed in a simulated body fluid (SBF) can be fabricated by this methodology.

Gomez-Vega, J.M.; Saiz, E.; Tomsia, A.P.; Marshall, G.W.; Marshall, S.J.

1998-12-01

183

Comparison of the Remineralizing Effects of Sodium Fluoride and Bioactive Glass Using Bioerodible Gel Systems  

PubMed Central

Background and aims A carious lesion is the accumulation of numerous episodes of de- and remineralization, rather than a unidirectional demineralization process. Tooth destruction can be arrested or reversed by the frequent delivery of fluoride or calcium/phosphorous ions to the tooth surface. The present study compared and evaluated the remineralization potential of sodium fluoride and bioactive glass delivered through a bioerodible gel system. Materials and methods Longitudinal sections of artificial carious lesions, created at the gingivofacial surface of 64 pri-mary maxillary incisors were photographed under a polarized light microscope and quantified for demineralization. The sec-tions were repositioned into the tooth form and randomly mounted in sets of four that simulated an arch form. The teeth were divided into 4 groups: 1) sodium fluoride films, 2) bioactive glass films, 3) control films placed interproximally and 4) non-treatment group. Following exposure to artificial saliva for 30 days, the lesions were again photographed and quantified as above. The recorded values were statistically analyzed using Student’s paired t-test for intragroup comparison, one-way ANOVA and Post-Hoc Tukey’s test for pairwise comparison. Results The sodium fluoride and bioactive gel groups showed significant remineralization compared with the control groups (P < 0.001). Conclusion Bioerodible gel films can be used to deliver remineralizing agents to enhance remineralization.

Ramashetty Prabhakar, Attiguppe; Arali, Veena

2009-01-01

184

A nanotectonics approach to produce hierarchically organized bioactive glass nanoparticles-based macrospheres.  

PubMed

Bioactive particles have been widely used in a series of biomedical applications due to their ability to promote bone-bonding and elicit favorable biological responses in therapies associated with the replacement and regeneration of mineralized tissues. In this work hierarchical architectures are prepared by an innovative methodology using SiO(2)-CaO sol-gel based nanoparticles. Inspired by colloidal crystals, spherical aggregates were formed on biomimetic superhydrophobic surfaces using bioactive glass nanoparticles (BG-NPs) able to promote bone regeneration. A highly ordered organization, a common feature of mineralized structures in Nature, was achieved at both nano- and microlevels, being the crystallization degree of the structures controlled by the evaporation rates taking place at room temperature (RT) or at 4 °C. The crystallization degree of the structures influenced the Ca/P ratio of the apatitic film formed at their surface, after 7 days of immersion in SBF. This allows the regulation of bioactive properties and the ability to release potential additives that could be also incorporated in such particles with a high efficiency. Such a versatile method to produce bioactive particles with controlled size and internal structure could open new possibilities in designing new spherical devices for orthopaedic applications, including tissue engineering. PMID:22992681

Luz, Gisela M; Mano, João F

2012-10-21

185

Comparison between the in vitro surface transformations of AP40 and RKKP bioactive glasses.  

PubMed

Two bioactive silica-phosphate glasses, AP40 and RKKP, were compared in their behaviour in simulated biological environment. Their chemical composition is practically identical, except that RKKP contains small amounts of amphoteric network-former oxides Ta2O5 and La2O3 (composition in wt% for AP40: beta-Ca3(PO4)2 24.50, SiO2 44.30, CaO 18.60, Na2O 4.60, K2O 0.19, MgO 2.82, CaF2 4.99; RKKP: beta-Ca3(PO4)2 24.23, SiO2 43.82, CaO 18.40, Na2O 4.55, K2O 0.19, MgO 2.79, CaF2 4.94, Ta2O5 0.99, La2O3 0.09). Previous investigations showed a better performance in osteopenic bone for RKKP. To gain more insight into these differences in biological behaviour, the in vitro bioactivity of the glasses was studied by treatment with a continuously replenished Hanks' Balanced Salt Solution (HBSS). The glasses were examined before and after HBSS treatment for 20 and 40 days by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Energy Dispersion (EDX), Raman and IR vibrational spectroscopies. Some slight but notable differences between the two glasses were observed after HBSS treatment. IR and EDX analyses showed that deposits formed on both glasses were composed of a calcium deficient carbonate-apatite; however, the layer formed on RKKP glass was found to be slightly more calcium deficient and thinner. EDX analysis evidenced the presence of a small percentage of F- ions only in the layers formed on the RKKP samples. The differences disclosed, although slight, can contribute to the understanding of the different biological behaviour previously observed. PMID:15744599

Krajewski, A; Ravaglioli, A; Tinti, A; Taddei, P; Mazzocchi, M; Martinetti, R; Fagnano, C; Fini, M

2005-02-01

186

Computational modelling of the mechanical environment of osteogenesis within a polylactic acid-calcium phosphate glass scaffold.  

PubMed

A computational model based on finite element method (FEM) and computational fluid dynamics (CFD) is developed to analyse the mechanical stimuli in a composite scaffold made of polylactic acid (PLA) matrix with calcium phosphate glass (Glass) particles. Different bioreactor loading conditions were simulated within the scaffold. In vitro perfusion conditions were reproduced in the model. Dynamic compression was also reproduced in an uncoupled fluid-structure scheme: deformation level was studied analyzing the mechanical response of scaffold alone under static compression while strain rate was studied considering the fluid flow induced by compression through fixed scaffold. Results of the model show that during perfusion test an inlet velocity of 25 microm/s generates on scaffold surface a fluid flow shear stress which may stimulate osteogenesis. Dynamic compression of 5% applied on the PLA-Glass scaffold with a strain rate of 0.005 s(-1) has the benefit to generate mechanical stimuli based on both solid shear strain and fluid flow shear stress on large scaffold surface area. Values of perfusion inlet velocity or compression strain rate one order of magnitude lower may promote cell proliferation while values one order of magnitude higher may be detrimental for cells. FEM-CFD scaffold models may help to determine loading conditions promoting bone formation and to interpret experimental results from a mechanical point of view. PMID:19477510

Milan, Jean-Louis; Planell, Josep A; Lacroix, Damien

2009-05-28

187

Polyvinylpyrrolidone modified bioactive glass fibers as tissue constructs: in vitro mesenchymal stem cell response.  

PubMed

The sol-gel synthesis of a bioactive glass (BAG) sol with the incorporation of polyvinylpyrrolidone and the subsequent spraying of short, discontinuous fibers is reported. The incorporation of the polymer into the BAG sol allowed for increased control of the rheological properties and resulted in a more homogeneous fibrous material when sprayed through an air gun. Reaction kinetics and sol viscosity were monitored and analyzed during synthesis, and fibers were characterized using scanning electron microscopy and thermal analysis. Fibers were sintered at 900 degrees C and were examined for in vitro bioactivity in a simulated body fluid solution. The presence of hydroxyapatite crystals is confirmed by examination with scanning electron microscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Both the proliferation rate and cell density of rat mesenchymal stem cells cultured on BAG fiber constructs of varying porosities were shown to be dependent upon fiber spacing. PMID:12926036

Hatcher, Brian M; Seegert, Charles A; Brennan, Anthony B

2003-09-15

188

Bioactive glasses-incorporated, core-shell-structured polypeptide/polysaccharide nanofibrous hydrogels.  

PubMed

Although the synthetic hydrogel materials capable of accelerating wound healing are being developed at a rapid pace, achieving inorganic-organic hybrid at nanoscale dimension in nanofibrous hydrogels is still a great challenge because of its notorious brittleness and microstructural stability in wet state. Here, we developed a new nanofibrous gelatin/bioactive glass (NF-GEL/BG) composite hydrogel by phase separation method and followed by arming the nanofibers network with counterionic chitosan-hyaluronic acid pairs for improving microstructural and thermal integrity. We achieve this feature by carrying an optimal balance of charges that allows the inorganic ion release in aqueous solution without minimal structure collapse. Therefore, such NF-GEL-based, polysaccharide-crosslinked bioactive hydrogel could afford a close biomimicry to the fibrous nanostructure and constituents of the hierarchically organized natural soft tissues to facilitate chronic, nonhealing wound treatment. PMID:23218343

Chen, Jian; Chen, Xiaoyi; Yang, Xianyan; Han, Chunmao; Gao, Changyou; Gou, Zhongru

2012-10-03

189

Effect of surfactant concentration on characteristics of mesoporous bioactive glass prepared by evaporation induced self-assembly process  

NASA Astrophysics Data System (ADS)

Mesoporous bioactive glasses were prepared by the evaporation-induced self-assembly method. The main objective of the present study is to determine the effect of surfactant concentration on the synthesis of SiO2–CaO–P2O5 mesoporous bioactive glasses; the characterization techniques used include X-ray diffraction, scanning electron microscopy and nitrogen adsorption and desorption isotherms. The results show that the specific surface area initially increased with increasing surfactant concentrations in the range of 2.1–9.1 wt% and significantly decreased from 328.7 to 204.0 m2/g in the concentration range of 9.1–12.5 wt%. For texture evaluation, the selected area electron diffraction patterns of the mesoporous bioactive glass precursor gels (9.1 wt% F127) calcined at different temperatures were analyzed; these patterns support the notion that some glassy structures in bioactive glasses become crystalline following heat treatment. The scanning electron microscopy images and X-ray diffraction patterns obtained agree with the inductively coupled plasma with atomic emission spectroscopy results as the mesoporous bioactive glasses can induce the formation of an apatite-like layer on their surface in SBF, even after short soaking periods.

Shih, Chi-Chung; Chien, Chi-Sheng; Kung, Jung-Chang; Chen, Jian-Chih; Chang, Shy-Shin; Lu, Pei-Shan; Shih, Chi-Jen

2013-01-01

190

In situ pH within particle beds of bioactive glasses.  

PubMed

The in vitro behavior of three bioactive glasses with seven particle size distributions was studied by measuring the in situ pH inside the particle beds for 48h in simulated body fluid (SBF). After immersion, the surface of the particles was characterized with a field emission scanning electron microscope equipped with an energy-dispersive X-ray analyzer. In addition, the results were compared with the reactions of the same glasses formed as plates. A similar trend in pH as a function of immersion time was observed for all systems. However, the pH inside the particle beds was markedly higher than that in the bulk SBF of the plates. The pH decreased as power functions with increasing particle size, i.e. with decreasing surface area. The in vitro reactivity expressed as layer formation strongly depended on the particle size and glass composition. The average thickness of the total reaction layer decreased with the increase in sample surface area. Well-developed silica and calcium phosphate layers typically observed on glass plates could be detected only on some particles freely exposed to the solution. No distinct reaction layers were observed on the finest particles, possibly because the layers spread out on the large surface area. Differences in the properties of the bulk SBF and the solution inside the particle bed were negligible for particles larger than 800microm. The results enhance our understanding of the in vitro reactions of bioactive glasses in various product forms and sizes. PMID:18502193

Zhang, Di; Hupa, Mikko; Hupa, Leena

2008-04-28

191

Porous bioactive scaffold of aliphatic polyurethane and hydroxyapatite for tissue regeneration  

Microsoft Academic Search

In this study, a new hydroxyapatite (HA)\\/polyurethane (PU) composite porous scaffold was developed by in situ polymerization. Aliphatic isophorone diisocyanate as a nontoxic and safe agent was adopted to produce the rigid segment in polyurethane polymerization. Hydroxyapatite powder was compounded in a PU polymer matrix during the polymeric process. The macrostructure and morphology as well as mechanical strength of the

Li Wang; Yubao Li; Yi Zuo; Li Zhang; Qin Zou; Lin Cheng; Hong Jiang

2009-01-01

192

Effect of long-term in vitro testing on the properties of bioactive glass-polysulfone composites.  

PubMed

The combination of bioactive ceramics and polymers can allow the preparation of composites with tailorable mechanical properties and bioactive behavior. In these composites, bioactive ceramics can act as a source of both reinforcement and bioactivity, while the polymer matrix can add toughness and processability to the material. On the other hand, the effect of using a highly dimensional unstable phase as a reinforcing agent on the long-term properties of the composite is a major concern regarding the lifetime of possible applications. In this work, a bioactive glass-polysulfone particulate composite was prepared by hot-pressing at 215 degrees C a mixture of polysulfone and different concentrations of bioactive glass particles (Bioglass 45S5, particle size range: 125-106 microm) to yield composites having 20 and 40 vol % of bioactive glass particles. The obtained composites were exposed to a simulated body fluid at 37 degrees C for different periods of time ranging from 1 h to 60 days. After the test, the mechanical properties of the composites were investigated by a four-point bending test, while DMS (dynamic mechanical spectroscopy) was used to identify the effect of water on the structure and behavior of the composite. The interface between glass particles and the polymer was also investigated by SEM/EDX and diffuse reflection infrared spectroscopy. The results showed that a decay in the mechanical properties of the composites within the first 20 h of test can occur. Otherwise, after this initial decay, no more pronounced reduction in properties could be noted. The analyses of the fracture surface of composites tested in vitro indicated the hydration of the surface of the particles. Therefore, it was concluded that water migration through the interface of the composite causes surface dissolution of glass particles and formation of voids, which were responsible for the observed decay in mechanical properties. Composites with modified interfaces revealed less damaged fracture surfaces than composites with untreated interfaces. PMID:20108891

Oréfice, Rodrigo; West, Jon; Latorre, Guy; Hench, Larry; Brennan, Anthony

2010-03-01

193

A bioactive sol-gel glass implant for in vivo gentamicin release. Experimental model in Rabbit.  

PubMed

Biomaterial pieces with osteogenic properties, suitable for use in the treatment of bone defects, were synthesized. The materials, which avoid bone infections, are exclusively composed of gentamicin sulfate and bioactive SiO2-CaO-P2O5 sol-gel glass (synthesized previously), and were manufactured by means of uniaxial and isostatic pressure of the mixed components. After implanting the pieces into rabbit femur, we studied (1) antibiotic release, determining the concentration in proximal and distal bone, liver, kidney, and lung as a function of time, and (2) bone growth as a consequence of the glass reactivity in the biological environment. The results demonstrated that the implants are good carriers for local gentamicin release into the local osseous tissue, where they show excellent biocompatibility and bone integration. Moreover, these implants are able to promote bone growth during the resorption process. PMID:16450408

Meseguer-Olmo, L; Ros-Nicolás, Mj; Vicente-Ortega, V; Alcaraz-Baños, M; Clavel-Sainz, M; Arcos, D; Ragel, C V; Vallet-Regí, M; Meseguer-Ortiz, Cl

2006-03-01

194

Biocompatibility and in vivo gentamicin release from bioactive sol-gel glass implants.  

PubMed

Biomaterial pieces, with suitable osteogenic properties for use in the treatment of bone defects and the capability to avoid bone infections, have been synthesized. These materials are composed exclusively of gentamicin sulfate and bioactive SiO(2)-CaO-P(2)O(5) sol-gel glass (previously synthesized). Implant processing was achieved by uniaxial and isostatic pressure of the components mixture. After implanting the pieces into rabbit femur, we studied (i) the antibiotic release, determining the concentration in proximal and distal bone, liver, kidney, and lung as a function of time; and (ii) the bone growth resulting from the glass reactivity in the biologic environment. The results indicate that the implants are good carriers for local gentamicin release in the osseous tissue, exhibiting excellent biocompatibility and bone integration. Moreover, these implants are able to promote bone growth during their resorption process. PMID:12115471

Meseguer-Olmo, L; Ros-Nicolás, M J; Clavel-Sainz, M; Vicente-Ortega, V; Alcaraz-Baños, M; Lax-Pérez, A; Arcos, D; Ragel, C V; Vallet-Regí, M

2002-09-01

195

Interpretation of electrical polarization and depolarization mechanisms of bioactive glasses in relation to ionic migration.  

PubMed

Electrical polarization and depolarization processes of the 45S5 type bioactive glass (BG) was studied by a thermally stimulated depolarization current (TSDC) and an complex impedance measurements. The depolarization processes were found to consist of three processes, which were observed as three peaks, P1, P2 and P3, in the TSDC spectra. P1 and P2, observed at lower than the glass transition temperature, were attributed to the sodium ionic migration from the interstitial positions after polarization procedure coordinated among neighboring silicate and phosphate to stabler positions. This migration process is presumed to relate to a shift in the ionic conductivity elucidated by the ac method. P3 observed at higher temperature for the BG polarized at more than 500 degrees Celsius for long period was ascribed to the ionic migration activated by a local deformation. The depolarization of BG consisted of three processes that depended on the neighboring coordination of traveling sodium ions during polarization. PMID:15109840

Obata, Akiko; Nakamura, Satoshi; Yamashita, Kimihiro

2004-09-01

196

Silicate and borate glasses as composite fillers: a bioactivity and biocompatibility study.  

PubMed

Composites filled with a silicate glass (CSi) and a new borate glass (CB) were developed and compared in terms of their in vitro behaviour both in acellular and cellular media. Acellular tests were carried out in SBF and the composites were characterized by SEM-EDS, XRD and ICP. Biocompatibility studies were investigated by in vitro cell culture with MG-63 osteoblast-like and human bone marrow cells. The growth of spherical calcium phosphate aggregates was observed in acellular medium on all composite surfaces indicating that these materials became potentially bioactive. The biological assessment resulted in a dissimilar behavior of the composites. The CSi demonstrated an inductive effect on the proliferation of cells. The cells showed a normal morphology and high growth rate when compared to standard culture plates. Contrarily, inhibition of cell proliferation occurred in the CB probably due to its high degradation rate, leading to high B and Mg ionic concentration in the cell culture medium. PMID:21556978

Lopes, P P; Ferreira, B J M Leite; Gomes, P S; Correia, R N; Fernandes, M H; Fernandes, M H V

2011-05-10

197

Sequential release of bioactive IGF-I and TGF-? 1 from PLGA microsphere-based scaffolds  

Microsoft Academic Search

Growth factors have become an important component for tissue engineering and regenerative medicine. Insulin-like growth factor-I (IGF-I) and transforming growth factor-beta1 (TGF-?1) in particular have great significance in cartilage tissue engineering. Here, we describe sequential release of IGF-I and TGF-?1 from modular designed poly(l,d-lactic-co-glycolic acid) (PLGA) scaffolds. Growth factors were encapsulated in PLGA microspheres using spontaneous emulsion, and in vitro

Ana Jaklenec; Alexandra Hinckfuss; Bahar Bilgen; Deborah M. Ciombor; Roy Aaron; Edith Mathiowitz

2008-01-01

198

Manufacture and evaluation of bioactive and biodegradable materials and scaffolds for tissue engineering  

Microsoft Academic Search

For tissue regeneration and tissue engineering applications, a number of bioactive and biodegradable composites, either porous or non-porous, were fabricated. The newly developed materials included tricalcium phosphate reinforced polyhydroxybutyrate and its copolymer, poorly crystallized hydroxyapatite reinforced chitin, and plasma sprayed hydroxyapatite reinforced poly(L-lactic acid). It was shown that these new materials could be successfully produced using the manufacturing techniques adopted.

M. Wang; L. J. Chen; J. Ni; J. Weng; C. Y. Yue

2001-01-01

199

Application of nuclear and physico-chemical analysis methods in the study of an after-implanting bioactive glass deposition on a titanium alloy, in view of optimizing the long-term bio-compatibility and operability.  

National Technical Information Service (NTIS)

To improve the anchorage of orthopedic prosthesis into surrounding bone, osteo-conductive biomaterials are usually used as coatings. Among usual coatings, we find bioactive glasses. The bioactive glass A9 is analyzed before and after implantation. It is p...

V. Brun

1999-01-01

200

Aluminum-free glass-ionomer bone cements with enhanced bioactivity and biodegradability.  

PubMed

Al-free glasses of general composition 0.340SiO2:0.300ZnO:(0.250-a-b)CaO:aSrO:bMgO:0.050Na2O:0.060P2O5 (a, b=0.000 or 0.125) were synthesized by melt quenching and their ability to form glass-ionomer cements was evaluated using poly(acrylic acid) and water. We evaluated the influence of the poly(acrylic acid) molecular weight and glass particle size in the cement mechanical performance. Higher compressive strength (25±5 MPa) and higher compressive elastic modulus (492±17 MPa) were achieved with a poly(acrylic acid) of 50 kDa and glass particle sizes between 63 and 125 ?m. Cements prepared with glass formulation a=0.125 and b=0.000 were analyzed after immersion in simulated body fluid; they presented a surface morphology consistent with a calcium phosphate coating and a Ca/P ratio of 1.55 (similar to calcium-deficient hydroxyapatite). Addition of starch to the cement formulation induced partial degradability after 8 weeks of immersion in phosphate buffer saline containing ?-amylase. Micro-computed tomography analysis revealed that the inclusion of starch increased the cement porosity from 35% to 42%. We were able to produce partially degradable Al-free glass-ionomer bone cements with mechanical performance, bioactivity and biodegradability suitable to be applied on non-load bearing sites and with the appropriate physical characteristics for osteointegration upon partial degradation. Zn release studies (concentrations between 413 ?M and 887 ?M) evidenced the necessity to tune the cement formulations to reduce the Zn concentration in the surrounding environment. PMID:23827583

Gomes, Filipa O; Pires, Ricardo A; Reis, Rui L

2012-12-13

201

Bioresorbable and bioactive composite materials based on polylactide foams filled with and coated by Bioglass® particles for tissue engineering applications  

Microsoft Academic Search

Poly(DL-lactide) (PDLLA) foams and bioactive glass (Bioglass®) particles were used to form bioresorbable and bioactive composite scaffolds for applications in bone tissue engineering. A thermally induced phase separation process was applied to prepare highly porous PDLLA foams filled with 10 wt % Bioglass® particles. Stable and homogeneous layers of Bioglass® particles on the surface of the PDLLA\\/Bioglass® composite foams as

A. R. Boccaccini; I. Notingher; V. Maquet; R. Jérôme

2003-01-01

202

Electrical stimulation modulates osteoblast proliferation and bone protein production through heparin-bioactivated conductive scaffolds.  

PubMed

Electrical fields are known to interact with human cells. This principle has been explored to regulate cellular activities for bone tissue regeneration. In this work, Saos-2 cells were cultured on conductive scaffolds made of biodegradable poly(L-lactide) and the heparin-containing, electrically conducting polypyrrole (PPy/HE) to study their reaction to electrical stimulation (ES) mediated through such scaffolds. Both the duration and intensity of ES enhanced cell proliferation, generating a unique electrical intensity and temporal "window" within which osteoblast proliferation was upmodulated in contrast to the downmodulation or ineffectiveness in other ES regions. The favourable ES intensity (200?mV/mm) was further investigated in terms of the gene activation and protein production of two important osteoblast markers characterised by extracellular matrix maturation and mineralisation, that is alkaline phosphatase (ALP) and osteocalcin (OC). Both genes were found activated and the relevant protein production increased significantly following ES. In contrast, ES in the down-modulation region (400?mV/mm) suppressed the production of both ALP and OC. This work demonstrated that important osteoblast markers can be modulated with specific ES parameters mediated through conductive polymer substrates, providing a unique strategy for bone tissue engineering. PMID:23124591

Meng, Shiyun; Rouabhia, Mahmoud; Zhang, Ze

2012-11-01

203

One-pot synthesis of magnetic and mesoporous bioactive glass composites and their sustained drug release property  

Microsoft Academic Search

A novel kind of magnetic and mesoporous bioactive glass (MMBG) composite with Fe3O4 nanoparticles confined and dispersed in ordered mesoporous glass matrices has been prepared by a one-pot synthesis route of simultaneous evaporation-induced self-assembly of Ca, P, Si and Fe sources and subsequent reduction in an H2 atmosphere. The MMBG composites exhibit the type IV isotherm curve with a well-defined

Xia Li; Xiupeng Wang; Zile Hua; Jianlin Shi

2008-01-01

204

Bioactive glass–ceramic coating for enhancing the in vitro corrosion resistance of biodegradable Mg alloy  

NASA Astrophysics Data System (ADS)

In this work, a bioactive 45S5 glass–ceramic coating was synthesized on magnesium (Mg) alloy substrate by using a sol–gel dip-coating method, to improve the initial corrosion resistance of AZ31 Mg alloy. The surface morphology and phase composition of the glass–ceramic coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The coating composed of amorphous phase and crystalline phase Na2Ca2Si3O9, with the thickness of ˜1.0 ?m, exhibited a uniform and crack-free surface morphology. The corrosion behavior of the uncoated and coated Mg alloy substrates was investigated by the electrochemical measurements and immersion tests in simulated body fluid (SBF). Potentiodynamic polarization tests recorded an increase of potential (Ecorr) form ?1.60 V to ?1.48 V, and a reduction of corrosion current density (icorr) from 4.48 ?A cm?2 to 0.16 ?A cm?2, due to the protection provided by the glass–ceramic coating. Immersion tests also showed the markedly improved corrosion resistance of the coated sample over the immersion period of 7 days. Moreover, after 14 days of immersion in SBF, the corrosion resistance of the coated sample declined due to the cracking of the glass–ceramic coating, which was confirmed by electrochemical impedance spectroscopy (EIS) analysis. The results suggested that the 45S5 glass–ceramic coated Mg alloy could provide a suitable corrosion behavior for use as degradable implants.

Ye, Xinyu; Cai, Shu; Dou, Ying; Xu, Guohua; Huang, Kai; Ren, Mengguo; Wang, Xuexin

2012-10-01

205

Interactions between the bioactive glass S53P4 and the atrophic rhinitis-associated microorganism klebsiella ozaenae.  

PubMed

In an aqueous environment, ions are released from a bioactive glass (BAG) and the pH rises in its vicinity. This may influence both growth and colonization of microorganisms. We studied the effects of the BAG S53P4 on the atrophic rhinitis-associated microorganism Klebsiella ozaenae. The glass was used in the form of granules or discs. Growth inhibition was studied using an agar plate test. Adhesion was studied by incubating bacterial suspension with the glass. The effect of the presence of the bacteria on the formation of the Si-rich layer on the bioactive glass was also analyzed. Furthermore, a follow up study of 19-74 months with ozena patients surgically treated with the BAG S53P4 was performed. The bioactive glass showed no clear growth inhibition of K. ozaenae in the agar plate test. K. ozaenae showed low adherence to the BAG S53P4. No growth of the microbe was seen on the glass during the 8 h incubations and the Si-rich layer was formed normally. The clinical follow-up study showed no infections of the implants and the symptoms of the patients were markedly reduced. Thus, the BAG S53P4 did not favor adhesion and colonization of K. ozaenae, in vitro, which is supported by the in vivo findings showing no BAG-associated infections or reinfections. PMID:10556853

Stoor, P; Söderling, E; Grenman, R

1999-01-01

206

Microscopic and spectroscopic investigation of bioactive glasses for antibiotic controlled release  

NASA Astrophysics Data System (ADS)

Bioactive glass with the composition 0.55SiO2·0.41CaO·0.04P2O5 was prepared following the sol-gel route as controlled delivery systems for tetracycline (TC). The maturation and drying of the gel under different conditions led to different behavior regarding the loading and release of TC from these matrices. The pore size modifications upon TC loading evidenced by BET method show different ability of the glass matrices with respect to TC incorporation, also supported by experimental EPR and fluorescence spectroscopy. EPR spectra of both TC solution and immobilized TC on the porous structure of glass specimens demonstrated changes in tetracycline structure during loading and upon adsorption. The TC release profile monitored by differential pulse voltammetry shows a maximum concentration after 2 h and a continuously slow release during the next 24 h. The obtained results demonstrate that the pores size modification related to different maturation and drying procedures seems to be a determinative factor in tetracycline release process.

Cavalu, S.; Banica, F.; Gruian, C.; Vanea, E.; Goller, G.; Simon, V.

2013-05-01

207

Synthesis and characterization of macroporous chitosan\\/calcium phosphate composite scaffolds for tissue engineering  

Microsoft Academic Search

Chitosan scaffolds reinforced by beta -tricalcium phosphate (beta -TCP)\\u000a and calcium phosphate invert glass were fabricated with a low-cost,\\u000a bioclean freeze-drying technique via thermally induced phase separation.\\u000a The microstructure, mechanical performance, biodegradation, and\\u000a bioactivity of the scaffolds were studied. The composite scaffolds were\\u000a macroporous, and the pore structures of the scaffolds with beta -TCP and\\u000a the glass appeared very different.

Y Zhang; Miqin Zhang

2001-01-01

208

One-pot synthesis of magnetic, macro/mesoporous bioactive glasses for bone tissue engineering  

NASA Astrophysics Data System (ADS)

Magnetic and macro/mesoporous bioactive glasses were synthesized by a one-pot method via a handy salt leaching technique. It was identified to be an effective and simple synthetic strategy. The non-ionic triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (P123), was used as the structure directing agent for mesoporous structure but also as the reductant to reduce the iron source into magnetic iron oxide. The prepared materials exhibited excellent super-paramagnetic property with interconnected macroporous (200-300 ?m) and mesoporous (3.4 nm) structure. Furthermore, their outstanding drug storage/release properties and rapid (5) induction of hydroxyapatite growth ability were investigated after immersing in simulated body fluid solution at 37 °C. Notably, the biocompatibility assessment confirmed that the materials obtained presented good biocompatibility and enhanced adherence of HeLa cells. Herein, the novel materials are expected to have potential application for bone tissue engineering.

Wang, Dan; Lin, Huiming; Jiang, Jingjie; Han, Xiao; Guo, Wei; Wu, Xiaodan; Jin, Yingxue; Qu, Fengyu

2013-04-01

209

Bioactive glass incorporation in calcium phosphate cement-based injectable bone substitute for improved in vitro biocompatibility and in vivo bone regeneration.  

PubMed

In this work, we fabricated injectable bone substitutes modified with the addition of bioactive glass powders synthesized via ultrasonic energy-assisted hydrothermal method to the calcium phosphate-based bone cement to improve its biocompatibility. The injectable bone substitutes was initially composed of a powder component (tetracalcium phosphate, dicalcium phosphate dihydrate and calcium sulfate dehydrate) and a liquid component (citric acid, chitosan and hydroxyl-propyl-methyl-cellulose) upon which various concentrations of bioactive glass were added: 0%, 10%, 20% and 30%. Setting time and compressive strength of the injectable bone substitutes were evaluated and observed to improve with the increase of bioactive glass content. Surface morphologies were observed via scanning electron microscope before and after submersion of the samples to simulated body fluid and increase in apatite formation was detected using x-ray diffraction machine. In vitro biocompatibility of the injectable bone substitutes was observed to improve with the addition of bioactive glass as the proliferation/adhesion behavior of cells on the material increased. Human gene markers were successfully expressed using real time-polymerase chain reaction and the samples were found to promote cell viability and be more biocompatible as the concentration of bioactive glass increases. In vivo biocompatibility of the samples containing 0% and 30% bioactive glass were evaluated using Micro-CT and histological staining after 3 months of implantation in male rabbits' femurs. No inflammatory reaction was observed and significant bone formation was promoted by the addition of bioactive glass to the injectable bone substitute system. PMID:23470354

Sadiasa, Alexander; Sarkar, Swapan Kumar; Franco, Rose Ann; Min, Young Ki; Lee, Byong Taek

2013-03-01

210

Turning coacervates into biohybrid glass: core/shell capsules formed by silica precipitation in protein/polysaccharide scaffolds.  

PubMed

In case of emergency, break glass: Biohybrid core/shell capsules suitable for encapsulation of volatile molecules can be formed through precipitation of amorphous silica in a protein/polyanion coacervate scaffold. The coacervate molds the final shape and structure of the capsule shell and provides an acidic microenvironment to locally induce hydrolysis and condensation of liquid silica precursors. PMID:23881535

Erni, Philipp; Dardelle, Gregory; Sillick, Matthew; Wong, Kenneth; Beaussoubre, Pascal; Fieber, Wolfgang

2013-07-23

211

In vitro degradation of porous poly( dl-lactide- co-glycolide) (PLGA)\\/bioactive glass composite foams with a polar structure  

Microsoft Academic Search

In vitro degradation of porous 50\\/50, 70\\/30 and 90\\/10 PLGA (poly(dl-lactide-co-glycolide)) foams and PLGA\\/bioactive glass (20wt%) composite foams was studied up to 16 weeks in TRIS (pH 7.4; 37°C). Polar PLGA\\/bioactive glass composite films were prepared by applying the bioactive glass (S53P4) on one side of the composite. Porous foams were made by solvent casting and pressure quenching with CO2.

Eeva Orava; Joni Korventausta; Meri Rosenberg; Mika Jokinen; Ari Rosling

2007-01-01

212

Effects on Growth and Osteogenic Differentiation of Mesenchymal Stem Cells by the Zinc-Added Sol-Gel Bioactive Glass Granules  

PubMed Central

Responses of mesenchymal stem cells (MSCs) cultured with zinc-added (2 and 5%) bioactive glass granules were evaluated in terms of cell growth and osteogenic differentiation. MSCs were cultured with different quantities (3, 10 and 30) of glass granules for up to 21 days in the osteogenic medium. Cell growth was stimulated by a small quantity of glasses, particularly those that contained zinc. Osteogenic differentiation, as assessed by alkaline phosphatase activity (ALP) activity, was significantly enhanced by the glasses, particularly with large quantities of glass and for prolonged culturing. Expression of bone-sialo protein (BSP) was significantly up-regulated around the bioactive glass granules. Moreover, the zinc addition significantly altered the ALP and BSP depending on the culture time and glass quantity. Cellular mineralization was improved in all glass samples, and particularly in the 2% zinc-glass. Taken together, the zinc addition to bioactive glass induced the MSCs growth and their osteogenic differentiation, at least to the level of zinc-free glass, and with even higher level observed depending on the quantity and culture time. These findings indicate that the zinc addition to bioactive glass may be useful in development of biomaterials for the stimulation of adult stem cell in bone tissue engineering.

Oh, Sun-Ae; Kim, So-Hee; Won, Jong-Eun; Kim, Jung-Ju; Shin, Ueon Sang; Kim, Hae-Won

2010-01-01

213

Biosilicate®–gelatine bone scaffolds by the foam replica technique: development and characterization  

NASA Astrophysics Data System (ADS)

The development of bioactive glass-ceramic materials has been a topic of great interest aiming at enhancing the mechanical strength of traditional bioactive scaffolds. In the present study, we test and demonstrate the use of Biosilicate® glass-ceramic powder to fabricate bone scaffolds by the foam replica method. Scaffolds possessing the main requirements for use in bone tissue engineering (95% porosity, 200–500 ?m pore size) were successfully produced. Gelatine coating was investigated as a simple approach to increase the mechanical competence of the scaffolds. The gelatine coating did not affect the interconnectivity of the pores and did not significantly affect the bioactivity of the Biosilicate® scaffold. The gelatine coating significantly improved the compressive strength (i.e. 0.80 ± 0.05 MPa of coated versus 0.06 ± 0.01 MPa of uncoated scaffolds) of the Biosilicate® scaffold. The combination of Biosilicate® glass-ceramic and gelatine is attractive for producing novel scaffolds for bone tissue engineering.

Desimone, Deborah; Li, Wei; Roether, Judith A.; Schubert, Dirk W.; Crovace, Murilo C.; Rodrigues, Ana Candida M.; Zanotto, Edgar D.; Boccaccini, Aldo R.

2013-08-01

214

Disinfection of Dentinal Tubules with 2% Chlorhexidine, 2% Metronidazole, Bioactive Glass when Compared with Calcium Hydroxide as Intracanal Medicaments  

Microsoft Academic Search

Thorough disinfection of the root canal system is essential for the success of root canal therapy. This requires the use of an intra-canal medicament. Enterococcus faecalis is the most frequently found species in persistent\\/secondary intracanal infection associated endodontic treatment failure. This study evaluates the disinfection of dentinal tubules using 2% chlorhexidine gel, 2% metronidazole gel, bioactive glass (S53P4) in comparison

Jogikalmat Krithikadatta; Rajamani Indira; Alfred Leo Dorothykalyani

2007-01-01

215

Good short-term outcome of primary total hip arthroplasty with cementless bioactive glass ceramic bottom-coated implants  

PubMed Central

Background and purpose Cementless total hip arthroplasty is currently favored by many orthopedic surgeons. The design of the porous surface is critically important for long-term fixation. We examined the clinical and radiographic outcome of the cementless titanium hip implant with a bottom coating of apatite-wollastonite containing bioactive glass ceramic. Methods We retrospectively reviewed 109 hips (92 patients) that had undergone primary cementless total hip arthroplasty with bioactive glass ceramic bottom-coated implants. The mean follow-up period was 7 (3–9) years. Hip joint function was evaluated with the Merle d’Aubigné and Postel hip score, and radiographic changes were determined from anteroposterior radiographs. Results The mean hip score improved from 9.7 preoperatively to 17 at the final follow-up. The overall survival rate was 100% at 9 years, when radiographic loosening or revision for any reason was used as the endpoint. 3 stems in 2 patients subsided more than 3 mm vertically within 1 year after implantation. Radiographs of the interface of the stem and femur were all classified as bone ingrowth fixation. Conclusions The short-term results of this study show good outcome for cementless implants with a bottom coating of apatite-wollastonite containing bioactive glass ceramic.

2012-01-01

216

Influence of cell culture medium composition on in vitro dissolution behavior of a fluoride-containing bioactive glass.  

PubMed

Bioactive glasses are used clinically for bone regeneration, and their bioactivity and cell compatibility are often characterized in vitro, using physiologically relevant test solutions. The aim of this study was to show the influence of varying medium characteristics (pH, composition, presence of proteins) on glass dissolution and apatite formation. The dissolution behavior of a fluoride-containing bioactive glass (BG) was investigated over a period of one week in Eagle's Minimal Essential Medium with Earle's Salts (MEM), supplemented with either, (a) acetate buffer, (b) 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer, (c) HEPES + carbonate, or (d) HEPES + carbonate + fetal bovine serum. Results show pronounced differences in pH, ion release, and apatite formation over 1 week: Despite its acidic pH (pH 5.8 after BG immersion, as compared to pH 7.4-8.3 for HEPES-containing media), apatite formation was fastest in acetate buffered (HEPES-free) MEM. Presence of carbonate resulted in formation of calcite (calcium carbonate). Presence of serum proteins, on the other hand, delayed apatite formation significantly. These results confirm that the composition and properties of a tissue culture medium are important factors during in vitro experiments and need to be taken into consideration when interpreting results from dissolution or cell culture studies. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013. PMID:23554092

Shah, Furqan A; Brauer, Delia S; Wilson, Rory M; Hill, Robert G; Hing, Karin A

2013-03-29

217

Structural changes of methemoglobin after adsorption on bioactive glass, as a function of surface functionalization and salt concentration  

NASA Astrophysics Data System (ADS)

Functional protein adsorption at liquid-solid interfaces has been intensively studied in the last years, however it is difficult to evidence directly conformational changes of the protein which are likely to appear upon adsorption. Spin labeling in combination with Electron Paramagnetic Resonance (EPR) spectroscopy was applied in this study to investigate adsorption of horse methemoglobin to bioactive glass (BG) similar in composition with 45S5 Bioglass®. X-band cw-EPR spectra of spin labeled methemoglobin in solution were compared to those obtained after adsorption on bioactive glass surface (functionalized and non-functionalized with glutaraldehyde), to extract information of the structure and dynamics in the vicinity of position ?-93. The concentration of methemoglobin adsorbed on BG substrate was determined from the intensity of cw-EPR spectra and correlated with images obtained by Scanning Electron Microscopy (SEM). Line shape analysis of the EPR spectra revealed that ionic strength does not induce significant conformational changes in the protein structure upon adsorption, however, the chemical treatment applied to the bioactive glass surface positively influences protein adsorption.

Gruian, C.; Vulpoi, A.; Steinhoff, H.-J.; Simon, S.

2012-05-01

218

Effect of nano-sized bioactive glass particles on the angiogenic properties of collagen based composites.  

PubMed

Angiogenesis is essential for tissue regeneration and repair. A growing body of evidence shows that the use of bioactive glasses (BG) in biomaterial-based tissue engineering (TE) strategies may improve angiogenesis and induce increased vascularization in TE constructs. This work investigated the effect of adding nano-sized BG particles (n-BG) on the angiogenic properties of bovine type I collagen/n-BG composites. Nano-sized (20-30 nm) BG particles of nominally 45S5 Bioglass® composition were used to prepare composite films, which were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in vivo angiogenic response was evaluated using the quail chorioallantoic membrane (CAM) as an model of angiogenesis. At 24 h post-implantation, 10 wt% n-BG containing collagen films stimulated angiogenesis by increasing by 41 % the number of blood vessels branch points. In contrast, composite films containing 20 wt% n-BG were found to inhibit angiogenesis. This experimental study provides the first evidence that addition of a limited concentration of n-BG (10 wt%) to collagen films induces an early angiogenic response making selected collagen/n-BG composites attractive matrices for tissue engineering and regenerative medicine. PMID:23430337

Vargas, Gabriela E; Haro Durand, Luis A; Cadena, Vanesa; Romero, Marcela; Mesones, Rosa Vera; Ma?kovi?, Mirza; Spallek, Stefanie; Spiecker, Erdmann; Boccaccini, Aldo R; Gorustovich, Alejandro A

2013-02-22

219

Effects of bioactive glass with and without mesoporous structures on desensitization in dentinal tubule occlusion  

NASA Astrophysics Data System (ADS)

Bioactive glass (BG) is a potential material for treating dentin hypersensitivity due to its high ability of dissolution. In this study, conventional BG and BG with well-ordered mesopore structures (MBG) were applied for dentinal tubule occlusion. We used X-ray diffractometer (XRD), scanning electronic microscope (SEM), and Fourier transform infrared (FTIR) to investigate the physiochemical properties and the dentinal tubule occlusion ability of BG and MBG groups. The results showed that the major crystallite phase of MBG and BG agents was monocalcium phosphate monohydrate. MBG pastes, mixed with 30 and 40 wt% phosphoric acid hardening solutions, had the ability to create a penetration depth greater than 50 ?m. These results showed that BG with mesoporous structures turned the pastes mixed with suitable phosphoric acid solution into a material with great ability for occluding dentinal tubules; it has a short reaction time and good operability, and these agents have better potential for the treatment of dentin hypersensitivity than BG without mesoporous structures.

Chen, Wen-Cheng; Kung, Jung-Chang; Chen, Cheng-Hwei; Hsiao, Yu-Cheng; Shih, Chi-Jen; Chien, Chi-Sheng

2013-10-01

220

Trehalose Maintains Bioactivity and Promotes Sustained Release of BMP-2 from Lyophilized CDHA Scaffolds for Enhanced Osteogenesis In Vitro and In Vivo  

PubMed Central

Calcium phosphate (Ca-P) scaffolds have been widely employed as a supportive matrix and delivery system for bone tissue engineering. Previous studies using osteoinductive growth factors loaded Ca-P scaffolds via passive adsorption often experience issues associated with easy inactivation and uncontrolled release. In present study, a new delivery system was fabricated using bone morphogenetic protein-2 (BMP-2) loaded calcium-deficient hydroxyapatite (CDHA) scaffold by lyophilization with addition of trehalose. The in vitro osteogenesis effects of this formulation were compared with lyophilized BMP-2/CDHA construct without trehalose and absorbed BMP-2/CDHA constructs with or without trehalose. The release characteristics and alkaline phosphatase (ALP) activity analyses showed that addition of trehalose could sufficiently protect BMP-2 bioactivity during lyophilization and achieve sustained BMP-2 release from lyophilized CDHA construct in vitro and in vivo. However, absorbed BMP-2/CDHA constructs with or without trehalose showed similar BMP-2 bioactivity and presented a burst release. Quantitative real-time PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) demonstrated that lyophilized BMP-2/CDHA construct with trehalose (lyo-tre-BMP-2) promoted osteogenic differentiation of bone marrow stromal cells (bMSCs) significantly and this formulation could preserve over 70% protein bioactivity after 5 weeks storage at 25°C. Micro-computed tomography, histological and fluorescent labeling analyses further demonstrated that lyo-tre-BMP-2 formulation combined with bMSCs led to the most percentage of new bone volume (38.79% ±5.32%) and area (40.71% ±7.14%) as well as the most percentage of fluorochrome stained bone area (alizarin red S: 2.64% ±0.44%, calcein: 6.08% ±1.37%) and mineral apposition rate (4.13±0.62 µm/day) in critical-sized rat cranial defects healing. Biomechanical tests also indicated the maximum stiffness (118.17±15.02 Mpa) and load of fracture (144.67±16.13 N). These results lay a potential framework for future study by using trehalose to preserve growth factor bioactivity and optimize release profile of Ca-P based delivery system for enhanced bone regeneration.

Zhao, Jun; Wang, Shaoyi; Bao, Jianqiang; Sun, Xiaojuan; Zhang, Xiaochen; Zhang, Xiuli; Ye, Dongxia; Wei, Jie; Liu, Changsheng; Jiang, Xinquan; Shen, Gang; Zhang, Zhiyuan

2013-01-01

221

Towards the controlled release of metal nanoparticles from biomaterials: Physico-chemical, morphological and bioactivity features of Cu-containing sol-gel glasses  

NASA Astrophysics Data System (ADS)

Two Cu-containing bioactive glasses were prepared and characterized in order to obtain a detailed description of chemical, morphological and bioactivity proprieties of potential Cu releasing systems. The characterization has demonstrated that by varying the synthesis procedure is possible to obtain two systems with Cu species in two different oxidation states and aggregation: (i) SGCu(ox) - oxidated Cu - (Cu oxidation state +2) homogeneously dispersed in the glass network matrix and (ii) SGCu(red) - metallic Cu - (Cu oxidation state 0) containing nano-particles (5-130 nm range) mainly present on the glass surface. The introduction of Cu maintains the bioactivity of the Cu-containing glasses almost unchanged, inducing a partial delay in the hydroxyapatite/hydroxy-carbonate apatite (HA/HCA) formation on the glass surface with respect to the reference glass (free Cu glass). During the bioactivity test, Cu is released from both Cu-containing glasses, in particular in the case of the SGCu(red) the presence of Cu nanoparticles (CuNPs) of diameter in the range 5-10 nm has been detected in solution.

Aina, Valentina; Cerrato, Giuseppina; Martra, Gianmario; Malavasi, Gianluca; Lusvardi, Gigliola; Menabue, Ledi

2013-10-01

222

Bioactive glass coatings affect the behavior of osteoblast-like cells.  

PubMed

Functionally graded coatings (FGCs) of bioactive glass on titanium alloy (Ti6Al4V) were fabricated by the enameling technique. These innovative coatings may be an alternative to plasma-sprayed, hydroxyapatite-coated implants. Previously we determined that a preconditioning treatment in simulated body fluid (SBF) helped to stabilize FGCs [Foppiano S et al. Acta Biomater 2006;2(2):133-42]. The primary goal of this work was to assess the in vitro cytocompatibility of preconditioned FGCs with MC3T3-E1.4 mouse pre-osteoblastic cells. We evaluated cell adhesion, proliferation and mineralization on FGCs in comparison to uncoated Ti6Al4V and tissue culture polystyrene (TCPS). No difference in cell adhesion was identified, whereas proliferation was significantly different on all materials, being highest on FGCs followed by TCPS and Ti6Al4V. Qualitative and quantitative mineralization assays indicated that mineralization occurred on all materials. The amount of inorganic phosphate released by the mineralizing layers was significantly different, being highest on TCPS, followed by FGC and uncoated Ti6Al4V. The secondary objective of this work was to assess the ability of the FGCs to affect gene expression, indirectly, by means of their dissolution products, which was assessed by real-time reverse-transcription polymerase chain reaction. The FGC dissolution products induced a 2-fold increase in the expression of Runx-2, and a 20% decrease in the expression of collagen type 1 with respect to TCPS extract. These genes are regulators of osteoblast differentiation and mineralization, respectively. The findings of this study indicate that preconditioned FGCs are cytocompatible and suggest that future work may allow composition changes to induce preferred gene expression. PMID:17466608

Foppiano, Silvia; Marshall, Sally J; Marshall, Grayson W; Saiz, Eduardo; Tomsia, Antoni P

2007-04-26

223

Bioresorbable and bioactive polymer\\/Bioglass® composites with tailored pore structure for tissue engineering applications  

Microsoft Academic Search

An overview about the development of porous bioresorbable composite materials for applications as scaffolds in tissue engineering is presented. A thermally induced phase separation method was developed to fabricate porous foam-like structures of poly(lactide-co-glycolide) (PLGA) containing bioactive glass particle additions (up to 50 wt.%) and exhibiting well-defined, oriented and interconnected porosity. The in vitro bioactivity and the degradability of the

Aldo R. Boccaccini; Veronique Maquet

2003-01-01

224

Effect of magnesia on the degradability and bioactivity of sol-gel derived SiO2-CaO-MgO-P2O5 system glasses.  

PubMed

Mesoporous 58SiO(2)-(38-x)CaO-xMgO-4P(2)O(5) glasses (where x=0, 5, 10 and 20 mol%) have been prepared by the sol-gel synthesis route. The effects of the substitution of MgO for CaO on glass degradation and bioactivity were studied in tris-(hydroxymethyl)-aminomethane and hydrochloric acid buffer solution (Tris-HCl) and simulated body fluid (SBF), respectively. It is observed that the synthesized glasses with various MgO contents possess the similar textural properties. The studies of in vitro degradability and bioactivity show that the rate of glass degradation gradually decreases with the increase of MgO and the formation of apatite layer on glass surface is retarded. The influences of the composition upon glass properties are explained in terms of their internal structures. PMID:20667433

Ma, J; Chen, C Z; Wang, D G; Jiao, Y; Shi, J Z

2010-07-06

225

Fabrication of a nanofibrous scaffold with improved bioactivity for culture of human dermal fibroblasts for skin regeneration  

Microsoft Academic Search

Engineering dermal substitutes with electrospun nanofibres have lately been of prime importance for skin tissue regeneration. Simple electrospinning technology served to produce nanofibrous scaffolds morphologically and structurally similar to the extracellular matrix of native tissues. The nanofibrous scaffolds of poly(l-lactic acid)-co-poly(epsilo-caprolactone) (PLACL) and PLACL\\/gelatin complexes were fabricated by the electrospinning process. These nanofibres were characterized for fibre morphology, membrane porosity,

Arun Richard Chandrasekaran; J. Venugopal; S. Sundarrajan; S. Ramakrishna

2011-01-01

226

Preliminary in vitro and in vivo characterizations of a sol-gel derived bioactive glass-ceramic system  

Microsoft Academic Search

This study investigates quantitatively and qualitatively the sol-gel derived bioactive glass-ceramic system (BGS)—apatite-wollastonite\\u000a (AW) type granules in the size range of 0.5–1 mm, as an effective graft material for bone augmentation and restoration. Scanning\\u000a electron micrographs (SEM) of the sintered granules revealed the rough material surface with micropores in the range 10–30\\u000a ?m. X-ray diffraction (XRD) pattern of the granules

S. Abiraman; H. K. Varma; T. V. Kumari; P. R. Umashankar; Annie John

2002-01-01

227

In vitro bioactivity and gene expression by cells cultured on titanium dioxide doped phosphate-based glasses.  

PubMed

In our previous study, glasses with 50 P(2)O(5)-(20-15) Na(2)O-30 CaO-(0-5 mol%) TiO(2) have been prepared by the conventional melt-quenching process. MG63 cell proliferation, gene expression, in vivo biocompatibility, and bioactivity of these glasses is the concern of this study. The results showed that addition of TiO(2) in small amounts up to 5 mol% enhanced the biocompatibility of these glasses. The cell metabolic activity was conspicuous, on 3 and 5 mol% TiO(2) compositions in particular, with no significant difference from Thermanox control over a period of 21 days. The findings from the gene expression study showed that, at day 1 and on 5 mol% TiO(2) glass, core binding protein factor alpha 1 (Cbfa1) and alkaline phosphatase (ALP) showed significantly lower transcription level; however, collagen type I alpha subunit I (COLIAI) and Osteonectin (Sparc) showed no significant differences compared to the control. At day 7, all these genes transcription levels were not significantly different form the control, but at day 14, they were significantly higher than the control. Moreover, there were no significant differences detected in these genes on both 3 and 5 mol% TiO(2) glasses up to 7 days. At day 14; however, 5 mol% TiO(2) glasses showed significantly higher level than 3 mol% TiO(2) composition. This was also correlated by the presence of new bone tissue at the bone-particles interface for 5 mol% TiO(2) composition after 5 weeks of implantation in rat calvarium. Regardless of this favourable cell response and gene up-regulation, these glasses showed no evidence of apatite layer formation after 14 days incubation in SBF. PMID:17412416

Abou Neel, Ensanya Ali; Mizoguchi, Toshihide; Ito, Michio; Bitar, Malak; Salih, Vehid; Knowles, Jonathan Campbell

2007-03-18

228

Bioactive Bioceramics  

Microsoft Academic Search

\\u000a Bioactive bioceramics as alternative to autografts and allografts include: bioactive glass, calcium carbonate (natural coral),\\u000a calcium sulfate and calcium phosphates of biologic (derived from bovine bone, coral and marine algae) or synthetic origin.\\u000a These bioceramics are available as granules or blocks (dense or porous), specially designed shapes (wedges, cylinders), cements\\u000a or as coatings on orthopedic or dental implants. Properties of

Racquel Z. LeGeros; Guy Daculsi; John P. LeGeros

229

Disinfection of dentinal tubules with 2% chlorhexidine, 2% metronidazole, bioactive glass when compared with calcium hydroxide as intracanal medicaments.  

PubMed

Thorough disinfection of the root canal system is essential for the success of root canal therapy. This requires the use of an intra-canal medicament. Enterococcus faecalis is the most frequently found species in persistent/secondary intracanal infection associated endodontic treatment failure. This study evaluates the disinfection of dentinal tubules using 2% chlorhexidine gel, 2% metronidazole gel, bioactive glass (S53P4) in comparison with calcium hydroxide. The antibacterial efficacy of the four medicaments against Enterococcus faecalis was assessed in vitro using extracted premolar teeth at the depths of 200 microm and 400 microm. The overall percentage inhibition of bacterial growth (at 200 microm and 400 microm depth) was 100% with 2% chlorhexidine gel. The inhibition of growth was moderate with 2% metronidazole gel (86.5%), followed by bioactive glass (62.8%) and calcium hydroxide (58.5%). It can be concluded from the present study that 2% chlorhexidine gel alone was most effective against E. faecalis when compared to other medicaments tested. PMID:18037062

Krithikadatta, Jogikalmat; Indira, Rajamani; Dorothykalyani, Alfred Leo

2007-12-01

230

Characterization of human primary osteoblast response on bioactive glass (BaG 13-93)- coated poly-L,DL-lactide (SR-PLA70) surface in vitro.  

PubMed

Bioabsorbable polylactide-based polymers are commonly used for bone reconstruction. Although these polymers have proven successful in many applications, they do not have the capacity to induce osteoconduction. Therefore, several strategies have been developed to manufacture osteoconductive polylactide-based composites. In this study, we have investigated in vitro response of human primary osteoblasts for self-reinforced poly-L,DL-lactide 70/30 (SR-PLA70) plates coated with spheres of bioactive glass 13-93 (SR-PLA70 + BaG). Osteoblasts were cultured on SR-PLA70 and SR-PLA70 + BaG plates for 2, 7, or 14 days. By day 7, both materials induced a reduction in total cell population. However, by day 14 the proliferative response of osteoblasts on SR-PLA70 + BaG surface was such that the cell population had regained similar levels as that of day 2 controls. Alkaline phosphatase activity was higher on SR-PLA70 at day 7 but declined to control levels by day 14. There were no significant time-dependent variations in alkaline phosphatase activity on SR-PLA70 + BaG. After in vitro hydrolysis for 7 days, the elemental analysis of SR-PLA70 + BaG surface showed the presence of mineral precipitates that were confirmed as crystalline hydroxyapatite. This was accompanied by osteoblast spreading, protrusions of microvilli adhered to BaG 19-39 surface, cuboidal phenotype and cell surface associated formation of hydroxyapatite microspheres. In conclusion, the SR-PLA70 + BaG composite is capable of inducing a proliferative response of human primary osteoblasts, and appears to support the development of mature osteoblast phenotype. Therefore, the SR-PLA70 + BaG composites appear as promising osteoconductive scaffold candidates for reconstruction and regeneration of bone matrix. PMID:16292763

Ruuttila, P; Niiranen, H; Kellomäki, M; Törmälä, P; Konttinen, Y T; Hukkanen, M

2006-07-01

231

Fabrication and biological characteristics of ?-tricalcium phosphate porous ceramic scaffolds reinforced with calcium phosphate glass  

Microsoft Academic Search

The fabrication process, compressive strength and biocompatibility of porous ?-tricalcium phosphate (?-TCP) ceramic scaffolds\\u000a reinforced with 45P2O5–22CaO–25Na2O–8MgO bioglass (?-TCP\\/BG) were investigated for their suitability as bone engineering materials. Porous ?-TCP\\/BG scaffolds\\u000a with macropore sizes of 200–500 ?m were prepared by coating porous polyurethane template with ?-TCP\\/BG slurry. The ?-TCP\\/BG\\u000a scaffolds showed interconnected porous structures and exhibited enhanced mechanical properties to those

S. Cai; G. H. Xu; X. Z. Yu; W. J. Zhang; Z. Y. Xiao; K. D. Yao

2009-01-01

232

The effect of rhBMP-2 on canine osteoblasts seeded onto 3D bioactive polycaprolactone scaffolds  

Microsoft Academic Search

Our strategy entails investigating the influence of varied concentrations (0, 10, 100 and 1000ng\\/ml) of human recombinant bone morphogenetic protein-2 (rhBMP-2) on the osteogenic expression of canine osteoblasts, seeded onto poly-caprolactone 20% tricalcium phosphate (PCL-TCP) scaffolds in vitro. Biochemical assay revealed that groups with rhBMP-2 displayed an initial burst in cell growth that was not dose-dependent. However, after 13 days,

B Rai; S. H Teoh; K. H Ho; D. W Hutmacher; T Cao; F Chen; K Yacob

2004-01-01

233

Stress–corrosion crack growth of Si–Na–K–Mg–Ca–P–O bioactive glasses in simulated human physiological environment  

Microsoft Academic Search

This paper describes research on the stress–corrosion crack growth (SCCG) behavior of a new series of bioactive glasses designed to fabricate coatings on Ti and Co–Cr-based implant alloys. These glasses should provide improved implant fixation between implant and exhibit good mechanical stability in vivo. It is then important to develop an understanding of the mechanisms that control environmentally assisted crack

Don R. Bloyer; James M. McNaney; Rowland M. Cannon; Eduardo Saiz; Antoni P. Tomsia; Robert O. Ritchiea

2007-01-01

234

The processing, mechanical properties and bioactivity of strontium based glass polyalkenoate cements  

Microsoft Academic Search

The suitability of zinc-based glass polyalkenoate cements (GPCs) for use in orthopaedics can be improved by the substitution\\u000a of strontium into the glass phase which should impart improved radiopacity and bone forming properties to the cements without\\u000a retarding strength. The purpose of this research was to produce novel GPCs based on calcium–strontium–zinc-silicate glasses\\u000a and to evaluate their mechanical properties and

Anthony Wren; Daniel Boyd; M. R. Towler

2008-01-01

235

The use of advanced diffraction methods in the study of the structure of a bioactive calcia: silica sol-gel glass.  

PubMed

Sol-gel derived calcium silicate glasses may be useful for the regeneration of damaged bone. The mechanism of bioactivity is as yet only partially understood but has been strongly linked to calcium dissolution from the glass matrix. In addition to the usual laboratory-based characterisation methods, we have used neutron diffraction with isotopic substitution to gain new insights into the nature of the atomic-scale calcium environment in bioactive sol-gel glasses, and have also used high energy X-ray total diffraction to probe the nature of the processes initiated when bioactive glass is immersed in vitro in simulated body fluid. The data obtained point to a complex calcium environment in which calcium is loosely bound within the glass network and may therefore be regarded as facile. Complex multi-stage dissolution and mineral growth phases were observed as a function of reaction time between 1 min and 30 days, leading eventually, via octacalcium phosphate, to the formation of a disordered hydroxyapatite (HA) layer on the glass surface. This methodology provides insight into the structure of key sites in these materials and key stages involved in their reactions, and thereby more generally into the behaviour of bone-regenerative materials that may facilitate improvements in tissue engineering applications. PMID:17122911

Newport, Robert John; Skipper, Laura J; Carta, Daniela; Pickup, David M; Sowrey, Frank E; Smith, Mark E; Saravanapavan, Priya; Hench, Larry L

2006-11-22

236

Three-Dimensional Visualization of Bioactive Glass-Bone Integration in a Rabbit Tibia Model Using Synchrotron X-Ray Microcomputed Tomography  

PubMed Central

Synchrotron X-ray microcomputed tomography (SR microCT), with a micron resolution, was used to evaluate the osteoconduction and osteointegration by borate bioactive glass after implantation 12 weeks in a rabbit tibia model. The study focused on the biomaterial–bone interface. Results from SR microCT two-dimensional and three-dimensional (3D) reconstructions provided precise imaging of the biomaterial–bone integration and detailed microarchitecture of both the bone-like glass graft and the newly formed trabecular bone. Osteoconduction, the formation of new trabecular bone within a tibia defect, occurred only in the tibiae implanted with teicoplanin-loaded borate glass but not in those with teicoplanin-loaded CaSO4 beads, indicating the excellent biocompatibility of the glass implants. 3D reconstruction of the tibiae also showed the infiltration of vascular tissue in both the bioactive glass graft and the new trabecular bone. This study indicates that SR microCT can serve as a valuable complementary technique for imaging bone repair when using bioactive glass implants.

Huang, Wenhai; Jia, Weitao; Rahaman, Mohamed N.; Liu, Xin; Tomsia, Antoni P.

2011-01-01

237

Fixation of distal femoral osteotomies with self-reinforced poly(L/DL)lactide 70:30/bioactive glass composite rods. An experimental study on rats.  

PubMed

Self-reinforced poly(L/DL)lactide 70:30/bioactive glass [SR-P(L/DL)LA/bioactive glass] composite rods, 2 mm in diameter and 36 mm in length, were implanted into the dorsal subcutaneous tissue of 16 rats. Osteotomies of the distal femur were fixed with these rods (2 x 15 mm) in 64 other rats. The follow-up times varied from one week to one year. After sacrifice, three-point bending and shear tests, and molecular weight measurements were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic, and oxytetracycline-fluorescence studies of the osteotomized and intact control femora were performed. At 24 weeks the mechanical properties had decreased significantly. Thirty-nine osteotomies healed uneventfully. One of the 64 evaluated osteotomies showed signs of infection at six weeks, and there were 19 non-unions and six delayed unions. In 20 operations the fixation was loose and out of these 14 non-unions were observed. No gross signs of inflammatory or foreign-body reactions were observed. The present investigation showed that the mechanical strength and fixation properties of SR-P(L/DL)LA/bioactive glass composite rods are suitable for fixation of cancellous bone osteotomies in rats as long as the operative technique is correct. The present article is the first report on the application of SR-P(L/DL)LA/bioactive glass composite rods for fixation of cancellous bone osteotomies. PMID:15335000

Tuomo, Pyhältö; Matti, Lapinsuo; Hannu, Pätiälä; Pentti, Rokkanen; Henna, Niiranen; Pertti, Törmälä

2004-03-01

238

Bioabsorbable Membrane and Bioactive Glass in the Treatment of Intrabony Defects in Patients with Generalized Aggressive Periodontitis: Results of a 12Month Clinical and Radiological Study  

Microsoft Academic Search

Background: The aim of this clinical and radiological prospective 5-year study was to compare the long- term effectiveness of a bioabsorbable membrane and a bioactive glass in the treatment of intrabony defects in patients with generalized aggressive periodontitis. Methods: Sixteen patients (11 women and five men) with generalized aggressive periodontitis were en- rolled in the study. The investigations were confined

Reiner Mengel; Doreen Schreiber; Lavin Flores-de-Jacoby

2003-01-01

239

The processing, mechanical properties and bioactivity of zinc based glass ionomer cements  

Microsoft Academic Search

The suitability of Glass Ionomer Cements (GICs) for use in orthopaedics is retarded by the presence in the glass phase of aluminium, a neurotoxin. Unfortunately, the aluminium ion plays an integral role in the setting process of a GIC and its absence is likely to hinder cement formation. However, zinc oxide, a bacteriocide, can act both as a network modifying

D. Boyd; M. R. Towler

2005-01-01

240

Bioactive materials for biomedical applications using sol-gel technology.  

PubMed

This review paper focuses on the sol-gel technology that has been applied in many of the potential research areas and highlights the importance of sol-gel technology for preparing bioactive materials for biomedical applications. The versatility of sol-gel chemistry enables us to manipulate the characteristics of material required for particular applications. Sol-gel derived materials have proved to be good biomaterials for coating films and for the construction of super-paramagnetic nanoparticles, bioactive glasses and fiberoptic applicators for various biomedical applications. The introduction of the sol-gel route in a conventional method of preparing implants improves the mechanical strength, biocompatibility and bioactivity of scaffolds and prevents corrosion of metallic implants. The use of organically modified silanes (ORMOSILS) yields flexible and bioactive materials for soft and hard tissue replacement. A novel approach of nitric-oxide-releasing sol-gels as antibacterial coatings for reducing the infection around orthopedic implants has also been discussed. PMID:18689920

Gupta, Radha; Kumar, Ashok

2008-08-08

241

Evaluation of bioactive glass and demineralized freeze dried bone allograft in the treatment of periodontal intraosseous defects: A comparative clinico-radiographic study  

PubMed Central

Aim: The purpose of this study was to evaluate the efficacy of demineralized freeze dried bone allograft (DFDBA) and bioactive glass by clinically and radiographically in periodontal intrabony defects for a period of 12 months. Materials and Methods: Ten systemically healthy patients diagnosed with chronic periodontitis, with radiographic evidence of at least a pair of contralateral vertical osseous defects were included in this study. Defect on one-side is treated with DFDBA and the other side with bioactive glass. Clinical and radiographic measurements were made at baseline 6 month and 12 month after the surgery. Results: Compared to baseline, the 12 month results indicated that both treatment modalities resulted in significant changes in all clinical parameters (gingival index, probing depth, clinical attachment level (CAL) and radiographic parameters (bone fill); P < 0.001*). However, sites treated with DFDBA exhibited statistically significantly more changes compared to the bioactive glass in probing depth reduction (2.5 ± 0.1 mm vs. 1.8 ± 0.1 mm) CAL gain 2.4 ± 0.1 mm versus 1.7 ± 0.2 mm; (P < 0.001*). At 12 months, sites treated with bioactive glass exhibited 56.99% bone fill and 64.76% bone fill for DFDBA sites, which is statistically significant (P < 0.05*). Conclusion: After 12 months, there was a significant difference between the two materials with sites grafted with DFDBA showing better reduction in probing pocket depth, gain in CAL and a greater percentage of bone fill when compared to that of bioactive glass.

Katuri, Kishore Kumar; Kumar, P. Jaya; Swarna, Chakrapani; Swamy, D. Narasimha; Arun, Kurumathur V.

2013-01-01

242

Comparisons between surfactant-templated mesoporous and conventional sol-gel-derived CaO-B{sub 2}O{sub 3}-SiO{sub 2} glasses: Compositional, textural and in vitro bioactive properties  

SciTech Connect

Compositional, textural and in vitro bioactive comparisons between surfactant-templated mesoporous (MCBS) and conventional sol-gel-derived CaO-B{sub 2}O{sub 3}-SiO{sub 2} (CBS) glasses are studied in this paper. CBS glasses are heterogeneous in composition. Due to the heterogeneity, melting boron oxide that formed during the heat treatment will fill in the pores that should have been generated by decomposition of calcium species. So, unlike other conventional sol-gel-derived bioactive glasses that have disordered and widely distributed mesopores, the CBS glasses are almost nonporous. MCBS glasses are more homogeneous in composition than CBS glasses, mainly ascribed to the effect of the surfactant. MCBS glasses of different compositions possess wormhole-like mesoporous structure and have similar pore size. In vitro bioactive tests show that wormhole-like MCBS glasses are more bioactive than CBS glasses, due to their high porosity. - Graphical abstract: Surfactant-templated mesoporous CaO-B{sub 2}O{sub 3}-SiO{sub 2} glasses (MCBS) are superior to conventional sol-gel-derived CaO-B{sub 2}O{sub 3}-SiO{sub 2} glasses (CBS) in compositional homogeneity, textural properties and in vitro bioactivity. Display Omitted.

Xiu Tongping [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, 1295 Dingxi Road, Shanghai 200050 (China); Graduate School of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100039 (China); Liu Qian [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, 1295 Dingxi Road, Shanghai 200050 (China)], E-mail: qianliu@sunm.shcnc.ac.cn; Wang Jiacheng [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, 1295 Dingxi Road, Shanghai 200050 (China); Graduate School of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100039 (China)

2008-04-15

243

Silicate and borate glasses as composite fillers: a bioactivity and biocompatibility study  

Microsoft Academic Search

Composites filled with a silicate glass (CSi) and a new borate glass (CB) were developed and compared in terms of their in\\u000a vitro behaviour both in acellular and cellular media. Acellular tests were carried out in SBF and the composites were characterized\\u000a by SEM-EDS, XRD and ICP. Biocompatibility studies were investigated by in vitro cell culture with MG-63 osteoblast-like and

P. P. Lopes; B. J. M. Leite Ferreira; P. S. Gomes; R. N. Correia; M. H. Fernandes

2011-01-01

244

Novel bioactive and biodegradable glass ceramics with high mechanical strength in the CaO--SiO2--B2O3 system.  

PubMed

Novel bioactive and biodegradable glass ceramics with high mechanical strength in the (50-x/2)CaO. SiO(2)--xB(2)O(3) (4.2 < or = x < or = 17.2) system were investigated. The systems consisted of three phases: monoclinic wollastonite, calcium metaborate, and amorphous borosilicate matrix. The glass ceramics containing 4.2 mol% and 8.4 mol% B(2)O(3) showed high bulk density and a dense microstructure. Mechanical strengths of the glass ceramics were higher than those of other bioactive ceramics: high compressive strength (2813 MPa), bending strength of 212 MPa, and fracture toughness of 3.12 MPa. m(1/2). The glass-ceramic formed apatite layer on their surface in the simulated body fluid and showed significant biodegradation. The degree of apatite formation in the glass ceramics depended on the calcium metaborate content and borosilicate glassy matrix. Additional calcium metaborate and borosilicate glassy matrix increased the apatite formation rate on the surface. It might be likely that calcium metaborate causes supersaturation of Ca ions, for its high solubility in SBF and the water-reactive borosilicate glassy matrix formed Sibond;OH groups on the surface to provide nucleation sites for apatite formation. Also, through in vitro test for the biocompatibility of the CaO--SiO(2)--B(2)O(3) glass ceramics, no cytotoxicity of the glass ceramics were found. The results on bioactivity and noncytotoxicity indicated that glass ceramics in the (50-x/2)CaO. SiO(2)--xB(2)O(3) (4.2 < or = x < or = 17.2) system could be useful as a biodegradable bone replacement material. PMID:14661252

Ryu, Hyun-Seung; Lee, Jung-Kun; Seo, Jun-Hyuk; Kim, Hwan; Hong, Kug Sun; Kim, Deug Joong; Lee, Jae Hyup; Lee, Dong-Ho; Chang, Bong-Soon; Lee, Choon-Ki; Chung, Sung-Soo

2004-01-01

245

Composite bone substitute materials based on beta-tricalcium phosphate and magnesium-containing sol-gel derived bioactive glass.  

PubMed

In the present study, bioceramic composites with improved mechanical and biological properties were synthesized by sintering mixtures of beta-tricalcium phosphate and SiO(2)-CaO-MgO-P(2)O(5) sol-gel derived bioactive glass at 1000-1200 degrees C. The physical, mechanical, structural and biological properties of the composites were evaluated by appropriate experiments such as microhardness, bending strength, XRD, SEM and MTT. The results showed that 1000 and 1100 degrees C were not appropriate temperatures for sintering the composites and in contrast, the microhardness, bending strength and bulk density significantly increased by increasing in quantity of bioglass phase when the samples were sintered at 1200 degrees C. No significant difference was found between the fracture toughness of the composites and pure beta-tricalcium phosphate. beta-tricalcium phosphate was structurally stable up to 1200 degrees C and did not transform to its alpha form even in the presence of the bioglass phase but migration of magnesium cations from the glass composition into its lattice structure was found by right-shift in XRD patterns, especially when the composite contained higher amount of bioglass component. Calcium silicate was also crystallized in the composition of the composites, which was more detectable in higher sintering temperatures. The results of the MTT test showed that proliferation of human osteosarcoma cells on the composites was considerably better than that of pure beta-TCP. PMID:19466530

Hesaraki, Saeed; Safari, Mojgan; Shokrgozar, Mohammad Ali

2009-05-23

246

A bioactive glass material for the delivery of bone morphogenetic proteins: Synthesis by the solution sol-gel method, physical and chemical analyses, and in vitro testing  

NASA Astrophysics Data System (ADS)

Although work of other investigators to date has provided much insight into the mechanism of bone repair using bone morphogenetic proteins (BMPs), the most fundamental clinical questions have remained unanswered; i.e., whether the BMPs can be placed in vivo in such a way as to force the initiation of bone regeneration and whether the regeneration response can be restricted to the desired location only. In this way, the choice of a suitable substrate for their delivery is central to the BMP repair methodology. In this research, highly homogeneous bioactive glasses outside of the normally accepted bioactivity composition range were synthesized by the solution sol-gel technique. They were subsequently assessed for bioactivity in vitro and their ion exchange with a simulated body fluid was measured over a 7-day period. Their immersion in the fluid resulted in rapid precipitation of fine-grained hydroxyapatite crystals, as observed by SEM and FT-IR techniques. The experimental glasses were also tested for cellular compatibility by culturing osteoblast cells on the surface of pressed discs of the material. Here, the glass was shown to Provide a suitable substrate for cell growth and proliferation. Altogether, these findings suggest that this type glass may serve as a suitable bone grafting material and delivery substrate for BMPs in the repair of osseous defects.

Mitchell, John Christopher

247

Synthesis, bioactivity and preliminary biocompatibility studies of glasses in the system CaO-MgO-SiO2-Na2O-P2O5-CaF2.  

PubMed

New compositions of bioactive glasses are proposed in the CaO-MgO-SiO(2)-Na(2)O-P(2)O(5)-CaF(2) system. Mineralization tests with immersion of the investigated glasses in simulated body fluid (SBF) at 37°C showed that the glasses favour the surface formation of hydroxyapatite (HA) from the early stages of the experiments. In the case of daily renewable SBF, monetite (CaHPO(4)) formation competed with the formation of HA. The influence of structural features of the glasses on their mineralization (bioactivity) performance is discussed. Preliminary in vitro experiments with osteoblasts' cell-cultures showed that the glasses are biocompatible and there is no evidence of toxicity. Sintering and devitrification studies of glass powder compacts were also performed. Glass-ceramics with attractive properties were obtained after heat treatment of the glasses at relatively low temperatures (up to 850°C). PMID:21188484

Tulyaganov, D U; Agathopoulos, S; Valerio, P; Balamurugan, A; Saranti, A; Karakassides, M A; Ferreira, J M F

2010-12-29

248

Compositional effects on the formation of a calcium phosphate layer and the response of osteoblast-like cells on polymer-bioactive glass composites  

Microsoft Academic Search

Biodegradable polymer-ceramic composites are attractive systems for bone tissue engineering applications. These composites have the combined advantages of the component phases, as well as the inherent ease in optimization where desired material properties can be tailored in a well-controlled manner. This study focuses on the optimization of a polylactide-co-glycolide (PLAGA) and 45S5 bioactive glass (BG) composite for bone tissue engineering.

Helen H. Lu; Amy Tang; Seong Cheol Oh; Jeffrey P. Spalazzi; Kathie Dionisio

2005-01-01

249

Preparation, structure and bioactivity of xAu2O3·(100 - x)[P2O5·CaO] glass system  

NASA Astrophysics Data System (ADS)

Gold doped calcium phosphate glasses were prepared by the melting method. The structure of Au2O3-P2O5-CaO glasses is investigated using X-ray diffraction, infrared absorption and Raman scattering. The depth characterization of their structures is essential for the understanding of the properties of biocompatible materials. Thermal analysis DTA and TGA were also made to study behavior under different temperature regions and to see chemical changes versus time and temperature of these glasses. Bioactivity of the glasses was investigated in vitro by examining apatite formation on the surface of glasses treated in acellular simulated body fluid (SBF) with ion concentrations nearly equal to those in human blood plasma. Formation of bioactive apatite layer on the samples treated in SBF for 28 days at 37 °C was confirmed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The effect of SBF soaking induces structural changes on the surface, reflected by the appearance of nano-crystalline particles agglomerated into micro-aggregates.

Regos, Adriana N.; Ardelean, I.

2011-12-01

250

Local structures of mesoporous bioactive glasses and their surface alterations in vitro: inferences from solid-state nuclear magnetic resonance  

PubMed Central

We review the benefits of using 29Si and 1H magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy for probing the local structures of both bulk and surface portions of mesoporous bioactive glasses (MBGs) of the CaO–SiO2?(P2O5) system. These mesoporous materials exhibit an ordered pore arrangement, and are promising candidates for improved bone and tooth implants. We discuss experimental MAS NMR results from three MBGs displaying different Ca, Si and P contents: the 29Si NMR spectra were recorded either directly by employing radio-frequency pulses to 29Si, or by magnetization transfers from neighbouring protons using cross polarization, thereby providing quantitative information about the silicate speciation present in the pore wall and at the MBG surface, respectively. The surface modifications were monitored for the three MBGs during their immersion in a simulated body fluid (SBF) for intervals between 30 min and one week. The results were formulated as a reaction sequence describing the interconversions between the distinct silicate species. We generally observed a depletion of Ca2+ ions at the MBG surface, and a minor condensation of the silicate-surface network over one week of SBF soaking.

Gunawidjaja, Philips N.; Mathew, Renny; Lo, Andy Y. H.; Izquierdo-Barba, Isabel; Garcia, Ana; Arcos, Daniel; Mattias Eden, Maria Vallet-Regi

2012-01-01

251

Surface properties and ion release from fluoride-containing bioactive glasses promote osteoblast differentiation and mineralization in vitro.  

PubMed

Bioactive glasses (BG) are suitable for bone regeneration applications as they bond with bone and can be tailored to release therapeutic ions. Fluoride, which is widely recognized to prevent dental caries, is efficacious in promoting bone formation and preventing osteoporosis-related fractures when administered at appropriate doses. To take advantage of these properties, we created BG incorporating increasing levels of fluoride whilst holding their silicate structure constant, and tested their effects on human osteoblasts in vitro. Our results demonstrate that, whilst cell proliferation was highest on low-fluoride-containing BG, markers for differentiation and mineralization were highest on BG with the highest fluoride contents, a likely effect of a combination of surface effects and ion release. Furthermore, osteoblasts exposed to the dissolution products of fluoride-containing BG or early doses of sodium fluoride showed increased alkaline phosphatase activity, a marker for bone mineralization, suggesting that fluoride can direct osteoblast differentiation. Taken together, these results suggest that BG that can release therapeutic levels of fluoride may find use in a range of bone regeneration applications. PMID:23128161

Gentleman, E; Stevens, M M; Hill, R G; Brauer, D S

2012-11-02

252

Fixation of distal femoral osteotomies with self-reinforced poly(L/DL)lactide 70:30 and self-reinforced poly(L/DL)lactide 70: 30/bioactive glass composite rods. an experimental study on rabbits.  

PubMed

Two self-reinforced poly(L/DL)lactide 70:30 or self-reinforced poly (L/DL)lactide 70:30/ bioactive glass (SR-P(L/DL)LA/bioactive glass) composite rods (2 mm x 40 mm) were implanted into the dorsal subcutaneous tissue and osteotomies of the distal femur were fixed with these rods (2 mm x 26 mm) in 36 rabbits. The follow-up times varied from 3 to 100 weeks. After the animals were killed, three-point bending and shear tests and molecular weight measurements were performed for subcutaneously placed rods. Radiological, histological, histomorphometrical, microradiographic and oxytetracycline-fluorescence studies of the osteotomized and intact control femora were performed. After 12 weeks the SR-P(L/DL)LA rods had fragmented into pieces and the mechanical properties could not be measured. The SR-P(L/DL)LA/bioactive glass rods lost their mechanical properties slower, and at 24 weeks the bending strength had decreased by 39% and the shear strength by 50%. After that the mechanical properties of the SR-P(L/DL)LA/bioactive glass rods could not be measured. All osteotomies healed well, and no gross signs of inflammatory reactions were observed. One slight displacement was seen in the three-week follow-up group with SR-P(L/DL)LA rods. Signs of resorption of the implants were seen after 48 weeks in the SR-P(L/DL)LA group and after 24 weeks in the SR-P(L/DL)LA/bioactive glass group. The SR-P(L/DL)LA/bioactive glass rods were almost totally resorbed from the bone at 100 weeks. The present investigation showed that the mechanical strength and fixation properties of the SR-P(L/DL)LA and the SR-P(L/DL)LA/bioactive glass composite rods are suitable for fixation of cancellous bone osteotomies in rabbits. PMID:16028593

Pyhältö, Tuomo; Lapinsuo, Matti; Pätiälä, Hannu; Niiranen, Henna; Törmälä, Pertti; Rokkanen, Pentti

2005-01-01

253

On the dissolution/reaction of small-grain Bioglass ® 45S5 and F-modified bioactive glasses in artificial saliva (AS)  

NASA Astrophysics Data System (ADS)

The reaction of small-grain Bioglass ® 45S5 in artificial saliva (AS), to produce a layer of hydroxy-apatite (HA) and/or hydroxy-carbonate apatite (HCA), has been studied and compared to the results obtained in a simple buffered solution (TRIS). Some potentially bioactive glasses based on the composition of Bioglass ® and containing CaF 2 (HCaCaF 2 5% and HNaCaF 2 5%) have also been studied, in order to analyze the effects/changes produced when a F-containing glass surface is contacted with AS. The insertion of fluorine has been proposed to improve bioactive glass bone-bonding ability, and to parallel fluorine-containing glass-ceramics currently used in dentistry. ICP-OES analysis of the solution, and FTIR spectroscopy of the solid samples provided compositional information on the stages of reaction. These data were integrated with XRD and the textural and morphological data, obtained by specific surface areas determination and TEM-EDS measurements. In the case of Bioglass ® 45S5, a comparison at corresponding reaction times indicates that the precipitation of an amorphous Ca-phosphate phase is faster in AS, but the crystallization of HA/HCA is delayed in AS with respect to the TRIS solution. For fluoride-containing glasses, the sample HCaCaF 2 5%, in which CaF 2 replaces part of CaO, possesses the fastest rate for HA/HCA crystallization (1 week) in AS. Some lines of interpretation for these results are proposed.

Aina, Valentina; Bertinetti, Luca; Cerrato, Giuseppina; Cerruti, Marta; Lusvardi, Gigliola; Malavasi, Gianluca; Morterra, Claudio; Tacconi, Linda; Menabue, Ledi

2011-02-01

254

Fabrication of a novel poly(3-hydroxyoctanoate)/ nanoscale bioactive glass composite film with potential as a multifunctional wound dressing  

SciTech Connect

Fabrication of a composite scaffold of nanobioglass (n-BG) 45S5 and poly(3-hydroxyocatnoate), P(3HO) was studied for the first time with the aim of developing a novel, multifunctional wound dressing. The incorporation of n-BG accelerated blood clotting time and its incorporation in the polymer matrix enhanced the wettability, surface roughness and bio-compatibility of the scaffold.

Rai, Ranjana; Keshavarz, Tajalli; Roy, Ipsita [Department of Molecular and Applied Biosciences, University of Westminster, London W1W 6UW (United Kingdom); Boccaccini, Aldo R. [Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom)] [Department of Materials Science and Engineering, University of Erlangen, Nuremberg Cauestr. 6. 91058 (Germany); Knowles, Jonathan C.; Salih, Vehid; Mordon, Nicola [Division of Biomterials and Tissue Engineering, UCL Eastman Dental Institute, London WCIX 8LD (United Kingdom); Locke, Ian C.; Gordge, Michael P. [Department of Biomedical Sciences, School of Lifesciences, University of Westminster, London W1W 6UW (United Kingdom); McCormick, Aine [Haemophilia Reference Centre, St. Thomas' Hospital, Lambeth Palace Road, London SE1 7EH (United Kingdom)

2010-06-02

255

Fabrication of a novel poly(3-hydroxyoctanoate) / nanoscale bioactive glass composite film with potential as a multifunctional wound dressing  

NASA Astrophysics Data System (ADS)

Fabrication of a composite scaffold of nanobioglass (n-BG) 45S5 and poly(3-hydroxyocatnoate), P(3HO) was studied for the first time with the aim of developing a novel, multifunctional wound dressing. The incorporation of n-BG accelerated blood clotting time and its incorporation in the polymer matrix enhanced the wettability, surface roughness and bio-compatibility of the scaffold.

Rai, Ranjana; Boccaccini, Aldo R.; Knowles, Jonathan C.; Locke, Ian C.; Gordge, Michael P.; McCormick, Aine; Salih, Vehid; Mordon, Nicola; Keshavarz, Tajalli; Roy, Ipsita

2010-06-01

256

87Sr solid-state NMR as a structurally sensitive tool for the investigation of materials: antiosteoporotic pharmaceuticals and bioactive glasses.  

PubMed

Strontium is an element of fundamental importance in biomedical science. Indeed, it has been demonstrated that Sr(2+) ions can promote bone growth and inhibit bone resorption. Thus, the oral administration of Sr-containing medications has been used clinically to prevent osteoporosis, and Sr-containing biomaterials have been developed for implant and tissue engineering applications. The bioavailability of strontium metal cations in the body and their kinetics of release from materials will depend on their local environment. It is thus crucial to be able to characterize, in detail, strontium environments in disordered phases such as bioactive glasses, to understand their structure and rationalize their properties. In this paper, we demonstrate that (87)Sr NMR spectroscopy can serve as a valuable tool of investigation. First, the implementation of high-sensitivity (87)Sr solid-state NMR experiments is presented using (87)Sr-labeled strontium malonate (with DFS (double field sweep), QCPMG (quadrupolar Carr-Purcell-Meiboom-Gill), and WURST (wideband, uniform rate, and smooth truncation) excitation). Then, it is shown that GIPAW DFT (gauge including projector augmented wave density functional theory) calculations can accurately compute (87)Sr NMR parameters. Last and most importantly, (87)Sr NMR is used for the study of a (Ca,Sr)-silicate bioactive glass of limited Sr content (only ~9 wt %). The spectrum is interpreted using structural models of the glass, which are generated through molecular dynamics (MD) simulations and relaxed by DFT, before performing GIPAW calculations of (87)Sr NMR parameters. Finally, changes in the (87)Sr NMR spectrum after immersion of the glass in simulated body fluid (SBF) are reported and discussed. PMID:22738329

Bonhomme, Christian; Gervais, Christel; Folliet, Nicolas; Pourpoint, Frédérique; Diogo, Cristina Coelho; Lao, Jonathan; Jallot, Edouard; Lacroix, Joséphine; Nedelec, Jean-Marie; Iuga, Dinu; Hanna, John V; Smith, Mark E; Xiang, Ye; Du, Jincheng; Laurencin, Danielle

2012-07-19

257

Porous poly( ?-hydroxyacid)\\/Bioglass ® composite scaffolds for bone tissue engineering. I: preparation and in vitro characterisation  

Microsoft Academic Search

Highly porous composites scaffolds of poly-d,l-lactide (PDLLA) and poly(lactide-co-glycolide) (PLGA) containing different amounts (10, 25 and 50wt%) of bioactive glass (45S5 Bioglass®) were prepared by thermally induced solid–liquid phase separation (TIPS) and subsequent solvent sublimation. The addition of increasing amounts of Bioglass® into the polymer foams decreased the pore volume. Conversely, the mechanical properties of the polymer materials were improved.

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

2004-01-01

258

Structure and properties of bioactive eutectic glasses based on the Ca3(PO4)2-CaSiO3-CaMg(SiO3)2 system.  

PubMed

Taking into account the phase equilibrium relationships within the Ca3(PO4)2-CaSiO3-CaMg(SiO3)2 ternary system, three bioactive glasses with a eutectic composition and analogous amounts of Ca3(PO4)2 (?40 wt.%) have been prepared. The structure of the glasses was investigated by 31P and 29Si magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. The glasses exhibited thermal expansion coefficients (50-600 °C) of 11.8-13.3×10(-6) °C(-1), a glass transition temperature of 790-720 °C and a softening temperature of 811-750 °C. The mechanical properties of the glasses were as follows: bending strength ?100 MPa, Young's modulus 94-83 GPa, Vickers microhardness 7.1-4.1 GPa and toughness 0.8 MPa m1/2. The bioactive properties were discussed in terms of their structure deduced by MAS-NMR spectroscopy and the field strength of the network modifiers (Mg2+ and Ca2+). A knowledge of the glass structure was important in predicting its bioactivity. PMID:22040687

Magallanes-Perdomo, M; De Aza, A H; Sobrados, I; Sanz, J; Pena, P

2011-10-20

259

Study of the interfacial reactions between a bioactive apatite-mullite glass-ceramic coating and titanium substrates using high angle annular dark field transmission electron microscopy.  

PubMed

Glass of generic composition SiO(2) . Al(2)O(3) . P(2)O(5) . CaO . CaF(2) will crystallise predominantly to apatite and mullite upon heat-treatment. Such ceramics are bioactive, osseoconductive, and have a high resistance to fracture. As a result, they are under investigation for use as biomedical device coatings, and in particular for orthopaedic implants. Previous work has shown that the material can be successfully enamelled to titanium with an interfacial reaction zone produced during heat treatment. The present study uses high angle annular dark field transmission electron microscopy (HAADF-TEM) to conduct a detailed examination of this region. Results show evidence of complex interfacial reactions following the diffusion of titanium into an intermediate layer and the production of titanium silicides and titanium phosphides. These results confirm previously hypothesised mechanisms for the bonding of silicate bioceramics with titanium alloys. PMID:19034617

Stanton, Kenneth T; O'Flynn, Kevin P; Nakahara, Shohei; Vanhumbeeck, Jean-François; Delucca, John M; Hooghan, Bobby

2008-11-26

260

Short- and medium-range structure of multicomponent bioactive glasses and melts: An assessment of the performances of shell-model and rigid-ion potentials  

NASA Astrophysics Data System (ADS)

Classical and ab initio molecular dynamics (MD) simulations have been carried out to investigate the effect of a different treatment of interatomic forces in modeling the structural properties of multicomponent glasses and melts. The simulated system is a soda-lime phosphosilicate composition with bioactive properties. Because the bioactivity of these materials depends on their medium-range structural features, such as the network connectivity and the Qn distribution (where Qn is a tetrahedral species bonded to n bridging oxygens) of silicon and phosphorus network formers, it is essential to assess whether, and up to what extent, classical potentials can reproduce these properties. The results indicate that the inclusion of the oxide ion polarization through a shell-model (SM) approach provides a more accurate representation of the medium-range structure compared to rigid-ion (RI) potentials. Insight into the causes of these improvements has been obtained by comparing the melt-and-quench transformation of a small sample of the same system, modeled using Car-Parrinello MD (CPMD), to the classical MD runs with SM and RI potentials. Both classical potentials show some limitations in reproducing the highly distorted structure of the melt denoted by the CPMD runs; however, the inclusion of polarization in the SM potential results in a better and qualitatively correct dynamical balance between the interconversion of Qn species during the cooling of the melt. This effect seems to reflect the slower decay of the fraction of structural defects during the cooling with the SM potential. Because these transient defects have a central role in mediating the Qn transformations, as previously proposed and confirmed by the current simulations, their presence in the melt is essential to produce an accurate final distribution of Qn species in the glass.

Tilocca, Antonio

2008-08-01

261

Short- and medium-range structure of multicomponent bioactive glasses and melts: An assessment of the performances of shell-model and rigid-ion potentials.  

PubMed

Classical and ab initio molecular dynamics (MD) simulations have been carried out to investigate the effect of a different treatment of interatomic forces in modeling the structural properties of multicomponent glasses and melts. The simulated system is a soda-lime phosphosilicate composition with bioactive properties. Because the bioactivity of these materials depends on their medium-range structural features, such as the network connectivity and the Q(n) distribution (where Q(n) is a tetrahedral species bonded to n bridging oxygens) of silicon and phosphorus network formers, it is essential to assess whether, and up to what extent, classical potentials can reproduce these properties. The results indicate that the inclusion of the oxide ion polarization through a shell-model (SM) approach provides a more accurate representation of the medium-range structure compared to rigid-ion (RI) potentials. Insight into the causes of these improvements has been obtained by comparing the melt-and-quench transformation of a small sample of the same system, modeled using Car-Parrinello MD (CPMD), to the classical MD runs with SM and RI potentials. Both classical potentials show some limitations in reproducing the highly distorted structure of the melt denoted by the CPMD runs; however, the inclusion of polarization in the SM potential results in a better and qualitatively correct dynamical balance between the interconversion of Q(n) species during the cooling of the melt. This effect seems to reflect the slower decay of the fraction of structural defects during the cooling with the SM potential. Because these transient defects have a central role in mediating the Q(n) transformations, as previously proposed and confirmed by the current simulations, their presence in the melt is essential to produce an accurate final distribution of Q(n) species in the glass. PMID:19044832

Tilocca, Antonio

2008-08-28

262

Highly bioactive P 2O 5–Na 2O–CaO–SiO 2 glass-ceramics  

Microsoft Academic Search

Glasses having a chemical composition between 1Na2O–2CaO–3SiO2 (1N2C3S) and 1.5Na2O–1.5CaO–3SiO2, containing 0, 2, 4 and 6 wt% P2O5, were crystallized to several volume percent through thermal treatments in the range 550–700 °C. These glasses and glass-ceramics were exposed to a simulated body fluid solution (SBF-K9 which is close to human plasma) for several time periods. Fourier transform infrared spectroscopy (FTIR)

Oscar Peitl; Edgar Dutra Zanotto; Larry L. Hench

2001-01-01

263

Sintering, crystallisation and biodegradation behaviour of Bioglass-derived glass-ceramics.  

PubMed

Sintering and crystallisation phenomena in powders of a typical bioactive glass composition (45S5 Bioglass) have been investigated in order to gain further understanding of the processes involved in the fabrication of Bioglass, based glass-ceramic scaffolds for tissue engineering applications. In situ experiments in an environmental scanning electron microscope with a heating stage were carried out to follow the morphology of Bioglass particles during sintering and crystallisation. Optimal processing parameters for the manufacture of Bioglass based glass-ceramic scaffolds by the foam-replica technique were determined. To assess the in vitro performance and bioreactivity of Bioglass -derived glass-ceramic scaffolds, the biodegradation of samples in simulated body fluid (SBF) was investigated using various techniques, including SEM, TEM, XRD and EDX. The mechanism of interaction of the glass-ceramic surface with SBF was determined, which involves (i) preferential dissolution at glass/crystal interfaces, (ii) break-down of crystalline particles into very fine grains through preferential dissolution at crystal structural defects, and (iii) amorphisation of the crystalline structure by introduction of point defects produced during ion exchange. The present report thus offers for the first time a complete assessment of the processing parameters, microstructure, and in vitro performance of Bioglass derived glass-ceramic scaffolds intended for bone tissue engineering. PMID:17955801

Boccaccini, Aldo R; Chen, Qizhi; Lefebvre, Leila; Gremillard, Laurent; Chevalier, Jérôme

2007-01-01

264

A prospective randomized 14-year follow-up study of bioactive glass and autogenous bone as bone graft substitutes in benign bone tumors.  

PubMed

A prospective randomized long-term follow-up study of bioactive glass (BG)-S53P4 and autogenous bone (AB) used as bone graft substitutes in benign bone tumor surgery during 1993-1997 was conducted. Twenty-one patients (11 in the BG group, 10 in the AB group) participated in a 14-year follow-up. X-rays and MRI scans were obtained, and in the BG group, CT scans were also performed. In the BG group, the filled cavity had a dense appearance on X-ray. MRI showed a mainly or partly fatty bone marrow, and in the large bone tumor group, remnants of glass granules were also observed. Increased cortical thickness was seen in nonossifying fibromas and enchondromas. BG-S53P4 is a safe and well-tolerated bone substitute with good long-term results. BG-S53P4 does not disturb the growth of bone in children. PMID:20524190

Lindfors, Nina C; Koski, Ilona; Heikkilä, Jouni T; Mattila, Kimmo; Aho, Allan J

2010-07-01

265

Magnetic bioactive glass ceramic in the system CaO–P 2 O 5 –SiO 2 –MgO–CaF 2 –MnO 2 –Fe 2 O 3 for hyperthermia treatment of bone tumor  

Microsoft Academic Search

Magnetic bioactive glass ceramic (MG) in the system CaO–SiO2–P2O5–MgO–CaF2–MnO2–Fe2O3 for hyperthermia treatment of bone tumor was synthesized. The phase composition was investigated by XRD. The magnetic property\\u000a was measured by VSM. The in vitro bioactivity was investigated by simulated body fluid (SBF) soaking experiment. Cell growth\\u000a on the surface of the material was evaluated by co-culturing osteoblast-like ROS17\\/2.8 cells with

Guangda Li; Shuying Feng; Dali Zhou

266

Crystallization processes at the surface of polylactic acid-bioactive glass composites during immersion in simulated body fluid.  

PubMed

We report on the crystallization processes occurring at the surface of PDLLA-Bioglass® composites immersed in simulated body fluid. Composites manufactured by injection molding and containing different amounts (0, 20, 30, and 50 wt %) of 45S5 Bioglass® particles were tested for durations up to 56 days and compared with Bioglass® particles alone. Crystallization processes were followed by visual inspection, X-ray diffraction (with Rietveld analysis) and scanning electron microscopy. Both calcite and hydroxyapatite were formed at the surface of all materials, but their relative ratio was dependent on the Bioglass® content and immersion time. Hydroxyapatite was always the major phase after sufficient immersion time, insuring bioactivity of such composites especially for Bioglass® content higher than 30 wt %. A scenario of crystallization is proposed. Rapid degradation of the composites with 50 wt % was also observed during immersion. Therefore, composites with 30 wt % of Bioglass® particles seem to exhibit the best balance between bioactivity and stability at least during the first weeks of immersion in contact with body fluids. PMID:21948519

Ginsac, Nathalie; Chenal, Jean-Marc; Meille, Sylvain; Pacard, Elodie; Zenati, Rachid; Hartmann, Daniel J; Chevalier, Jérôme

2011-09-21

267

Bioactive glass microspheres as osteopromotive inlays in macrotextured surfaces of Ti and CoCr alloy bone implants: Trapezoidal surface grooves without inlay most efficient in resisting torsional forces  

Microsoft Academic Search

We have tested the efficacy of porous bioactive glass (BG) inlays in enhancement of implant osseointegration. A total of 24 sheep underwent bilateral surgical implantation of three parallel implants on the anteromedial cortical surface of each tibia. The disc-shaped implants made of Ti6Al4V or cobalt chromium (CoCr) alloys had two parallel surface grooves (trapezoidal space with bottom widening) filled with

Pauli Keränen; Niko Moritz; Jessica J. Alm; Heimo Ylänen; Bertel Kommonen; Hannu T. Aro

2011-01-01

268

Bioactive glass microspheres as osteopromotive inlays in macrotextured surfaces of Ti and CoCr alloy bone implants: trapezoidal surface grooves without inlay most efficient in resisting torsional forces.  

PubMed

We have tested the efficacy of porous bioactive glass (BG) inlays in enhancement of implant osseointegration. A total of 24 sheep underwent bilateral surgical implantation of three parallel implants on the anteromedial cortical surface of each tibia. The disc-shaped implants made of Ti6Al4V or cobalt chromium (CoCr) alloys had two parallel surface grooves (trapezoidal space with bottom widening) filled with sintered 100% bioactive glass microspheres or a selected mixture of bioactive and biocompatible glass microspheres. The surface of uncoated control implants was smooth, grit-blasted or had unfilled grooves. A subgroup of control smooth CoCr implants was coated with two or three BG layers. Implant incorporation with bone was evaluated using torque testing to failure, scanning electron microscopy and morphometry at 12 and 25 weeks. A total of 144 in vivo implants and 16 ex vivo cemented control implants were analyzed. Control Ti6Al4V implants with unfilled trapezoidal grooves showed highest torsional failure loads with excellent ingrowth of new bone and remodeling of ingrown bone into lamellar bone. Implants with BG inlays and microroughened control Ti6Al4V implants showed significantly lower torsional failure loads than control Ti6Al4V implants with unfilled grooves. In conclusion, BG inlays failed to enhance biological implant fixation. Macrotextured surface was more effective than grit-blasting in promotion of mechanical incorporation. PMID:21783158

Keränen, Pauli; Moritz, Niko; Alm, Jessica J; Ylänen, Heimo; Kommonen, Bertel; Aro, Hannu T

2011-05-30

269

Single-step electrochemical deposition of antimicrobial orthopaedic coatings based on a bioactive glass/chitosan/nano-silver composite system.  

PubMed

Composite orthopaedic coatings with antibacterial capability containing chitosan, Bioglass® particles (9.8?m) and silver nanoparticles (Ag-np) were fabricated using a single-step electrophoretic deposition (EPD) technique, and their structural and preliminary in vitro bactericidal and cellular properties were investigated. Stainless steel 316 was used as a standard metallic orthopaedic substrate. The coatings were compared with EPD coatings of chitosan and chitosan/Bioglass®. The ability of chitosan as both a complexing and stabilizing agent was utilized to form uniformly deposited Ag-np. Due to the presence of Bioglass® particles, the coatings were bioactive in terms of forming carbonated hydroxyapatite in simulated body fluid (SBF). Less than 7wt.% of the incorporated silver was released over the course of 28days in SBF and the possibility of manipulating the release rate by varying the deposition order of coating layers was shown. The low released concentration of Ag ions (<2.5ppm) was efficiently antibacterial against Staphyloccocus aureus up to 10days. Although chitosan and chitosan/Bioglass® coating supported proliferation of MG-63 osteoblast-like cells up to 7days of culture, chitosan/Bioglass®/Ag-np coatings containing 342 ?g of Ag-np showed cytotoxic effects. This was attributed to the relatively high concentration of Ag-np incorporated in the coatings. PMID:23511807

Pishbin, F; Mouriño, V; Gilchrist, J B; McComb, D W; Kreppel, S; Salih, V; Ryan, M P; Boccaccini, A R

2013-03-16

270

Surface and chemical study of SiO{sub 2} {center_dot} P{sub 2}O{sub 5} {center_dot} CaO {center_dot} (MgO) bioactive glasses  

SciTech Connect

Glasses in SiO{sub 2} {center_dot} CaO {center_dot} P{sub 2}O{sub 5} and SiO{sub 2} {center_dot} CaO {center_dot} P{sub 2}O{sub 5} {center_dot} MgO systems have been prepared by a sol-gel synthesis procedure. The calcined glasses have been characterized by XRD, N{sub 2} adsorption, Hg porosimetry, XPS and TEM have been also subjected to in vitro tests (immersion in a simulated body fluid) to evaluate their bioactivity. The presence of magnesium in the glasses increases the surface area and porosity, but is retards the formation of an apatite layer on the surface of glasses in the in vitro test. The XPS reveals that the surfaces of the glasses are richer in phosphorus and poorer in calcium than the bulk, whereas the magnesium, if present, associates preferentially to phosphorus at the glass surface. The TEM shows the presence of apatite-like calcium phosphate domains in the magnesium -free glasses, which are barely detected in the glasses, which contain this element. These apatitic domains are proposed to be the nucleation centers for the crystallization of apatite in the in vitro tests.

Perez-Pariente, J.; Balas, F.; Vallet-Regi, M.

2000-03-01

271

In vivo bone regeneration using a novel porous bioactive composite  

NASA Astrophysics Data System (ADS)

Many commercial bone graft substitutes (BGS) and experimental bone tissue engineering scaffolds have been developed for bone repair and regeneration. This study reports the in vivo bone regeneration using a newly developed porous bioactive and resorbable composite that is composed of bioactive glass (BG), collagen (COL), hyaluronic acid (HYA) and phosphatidylserine (PS), BG-COL-HYA-PS. The composite was prepared by a combination of sol-gel and freeze-drying methods. A rabbit radius defect model was used to evaluate bone regeneration at time points of 2, 4 and 8 weeks. Techniques including radiography, histology, and micro-CT were applied to characterize the new bone formation. 8 weeks results showed that (1) nearly complete bone regeneration was achieved for the BG-COL-HYA-PS composite that was combined with a bovine bone morphogenetic protein (BMP); (2) partial bone regeneration was achieved for the BG-COL-HYA-PS composites alone; and (3) control remained empty. This study demonstrated that the novel BG-COL-HYA-PS, with or without the grafting of BMP incorporation, is a promising BGS or a tissue engineering scaffold for non-load bearing orthopaedic applications.

Xie, En; Hu, Yunyu; Chen, Xiaofeng; Bai, Xuedong; Li, Dan; Ren, Li; Zhang, Ziru

2008-11-01

272

Electrophoretic deposition of porous hydroxyapatite scaffold.  

PubMed

Bioactive porous hydroxyapatite (HA) scaffold was fabricated using electrophoretic deposition (EPD) technique in the present work. Bulk HA scaffold was achieved by repeated deposition. The green scaffold was sintered at 1200 degrees C to 82% of the theoretical density. Scanning electron microscopy examination and mercury porosimetry measurement have shown that the porosity remains interconnected and a range of pore size from several microns to hundreds of microns was obtained. X-ray diffraction analysis was performed and confirmed that there is no HA decomposition during the sintering process. Mechanical characterization has also shown that the EPD scaffold possesses excellent properties. Cell culturing experiment was carried out and the result shows that the scaffold bioactivity is not only dependent on the interconnectivity of the pores, but also the pore size. PMID:12809779

Ma, J; Wang, C; Peng, K W

2003-09-01

273

Porous bioactive materials  

NASA Astrophysics Data System (ADS)

Bioactive materials chemically bond to tissues through the development of biologically active apatite. Porous structures in biomaterials are designed to enhance bioactivity, grow artificial tissues and achieve better integration with host tissues in the body. The goal of this research is to design, fabricate and characterize novel porous bioactive materials. 3D ordered macroporous bioactive glasses (3DOM-BGs, pore size: 200--1000 nm) were prepared using a sol-gel process and colloidal crystal templates. 3DOM-BGs are more bioactive and degradable than mesoporous (pore size <50 nm) sol-gel BGs in simulated body fluid (SBF). Apatite formation and 3DOM-BG degradation rates increased with the decrease of soaking ratio. Apatite induction time in SBF increased with 3DOM-BG calcination temperature (600--800°C). Apatite formation and 3DOMBG degradation were slightly enhanced for a phosphate containing composition. Large 3DOM-BG particles formed less apatite and degraded less completely as compared with small particles. An increase in macropore size slowed down 3DOM-BG degradation and apatite formation processes. After heating the converted apatite at a temperature higher than 700°C, highly crystalline hydroxyapatite and a minor tri-calcium phosphate phase formed. 3DOM-BGs have potential applications as bone/periodontal fillers, and drugs and biological factors delivery agents. Anchoring artificial soft tissues (e.g., cartilage) to native bone presents a challenge. Porous polymer/bioactive glass composites are candidate materials for engineering artificial soft tissue/bone interfaces. Porous composites consisting of polymer matrices (e.g., polysulfone, polylactide, and polyurethane) and bioactive glass particles were prepared by polymer phase separation techniques adapted to include ceramic particles. Composites (thickness: 200--500 mum) have asymmetric structures with dense top layers and porous structures beneath. Porous structures consist of large pores (>100 mum) in a network of smaller (<10 mum) interconnected pores. Dense layers can be removed and large pores exposed by abrasion or salt leaching techniques. Composite modulus was enhanced with the increase of glass content, due to the change in composition and pore content. The growth of bone-like apatite on and inside composites after soaking in SBF demonstrated their potential for integration with bone. Cell culture studies revealed that composite surfaces were suitable for attachment, spreading and proliferation of chondrocytes.

Zhang, Kai

274

Recent advances in bone tissue engineering scaffolds  

PubMed Central

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

Bose, Susmita; Roy, Mangal; Bandyopadhyay, Amit

2012-01-01

275

In Vitro Effect of Air-abrasion Operating Parameters on Dynamic Cutting Characteristics of Alumina and Bio-active Glass Powders.  

PubMed

SUMMARY Minimally invasive dentistry advocates the maintenance of all repairable tooth structures during operative caries management in combination with remineralization strategies. This study evaluated the effect of air-abrasion operating parameters on its cutting efficiency/pattern using bio-active glass (BAG) powder and alumina powder as a control in order to develop its use as a minimally invasive operative technique. The cutting efficiency/pattern assessment on an enamel analogue, Macor, was preceded by studying the powder flow rate (PFR) of two different commercial intraoral air-abrasion units with differing powder-air admix systems. The parameters tested included air pressure, powder flow rate, nozzle-substrate distance, nozzle angle, shrouding the air stream with a curtain of water, and the chemistry of abrasive powder. The abraded troughs were scanned and analyzed using confocal white light profilometry and MountainsMap surface analysis software. Data were analyzed statistically using one-way and repeated-measures analysis of variance tests (p=0.05). The air-abrasion unit using a vibration mechanism to admix the abrasive powder with the air stream exhibited a constant PFR regardless of the set air pressure. Significant differences in cutting efficiency were observed according to the tested parameters (p<0.05). Alumina powder removed significantly more material than did BAG powder. Using low air pressure and suitable consideration of the effect of air-abrasion parameters on cutting efficiency/patterns can improve the ultraconservative cutting characteristics of BAG air-abrasion, thereby allowing an introduction of this technology for the controlled cleaning/removal of enamel, where it is indicated clinically. PMID:23718212

Milly, H; Austin, Rs; Thompson, I; Banerjee, A

2013-05-29

276

Novel Antibacterial Nanofibrous PLLA Scaffolds  

PubMed Central

In order to achieve high local bioactivity and low systemic side effects of antibiotics in the treatment of dental, periodontal and bone infections, a localized and temporally controlled delivery system is crucial. In this study, a three-dimensional (3D) porous tissue engineering scaffold was developed with the ability to release antibiotics in a controlled fashion for long-term inhibition of bacterial growth. The highly soluble antibiotic drug, Doxycycline (DOXY), was successfully incorporated into PLGA nanospheres using a modified water-in-oil-in-oil (w/o/o) emulsion method. The PLGA nanospheres (NS) were then incorporated into prefabricated nanofibrous PLLA scaffolds with a well interconnected macroporous structure. The release kinetics of DOXY from four different PLGA NS formulations on a PLLA scaffold was investigated. DOXY could be released from the NS-scaffolds in a locally and temporally controlled manner. The DOXY release is controlled by DOXY diffusion out of the NS and is strongly dependent upon the physical and chemical properties of the PLGA. While PLGA50-6.5K, PLGA50-64K, and PLGA75-113K NS-scaffolds discharge DOXY rapidly with a high initial burst release, PLGA85-142K NS-scaffold can extend the release of DOXY to longer than 6 weeks with a low initial burst release. Compared to NS alone, the NS incorporated on a 3-D scaffold had significantly reduced the initial burst release. In vitro antibacterial tests of PLGA85 NS-scaffold demonstrated its ability to inhibit common bacterial growth (S.aureus and E.coli) for a prolonged duration. The successful incorporation of DOXY onto 3-D scaffolds and its controlled release from scaffolds extends the usage of nano-fibrous scaffolds from the delivery of large molecules such as growth factors to the delivery of small hydrophilic drugs, allowing for a broader application and a more complex tissue engineering strategy.

Feng, Kai; Sun, Hongli; Bradley, Mark A.; Dupler, Ellen J.; Giannobile, William V.; Ma, Peter X.

2010-01-01

277

Pre-mineralisation of starch/polycrapolactone bone tissue engineering scaffolds by a calcium-silicate-based process.  

PubMed

This work describes a new methodology to produce bioactive coatings on the surface of starch-based biodegradable polymers or other degradable polymeric biomaterials. As an alternative to the more typical bioactive glass precursors, a calcium silicate gel is being employed as a nucleating agent, for inducing the biomimetic formation of a calcium-phosphate (Ca-P) layer. The method has the advantage of being able to coat efficiently both compact materials and porous 3-D architectures aimed at being used on tissue replacement applications and as bone tissue engineering scaffolds. This treatment is also very effective in reducing the incubation periods, being possible to observe the formation of an apatite-like layer, only after 12 h of immersion in a simulated body fluid (SBF). The apatite coatings formed on the compact surfaces or along the fibres of a fibre mesh scaffold structure made from a starch/polycrapolactone blend (SPCL) were analysed and compared in terms of morphology, chemical composition and structure. After the first days of SBF immersion, the apatite-like films exhibit the typical cauliflower like morphology. With increasing immersion times, these films exhibited a partially amorphous nature and the Ca/P ratios became very closer to the value attributed to hydroxyapatite (1.67). It was possible to fully pre-mineralise the SPCL scaffolds and simultaneously to keep the porous morphology of the fibre-bonded scaffold. PMID:15332631

Oliveira, A L; Reis, R L

2004-04-01

278

Surface transformations of Bioglass 45S5 during scaffold synthesis for bone tissue engineering.  

PubMed

In physiological fluid, a layer of hydroxycarbonate apatite, similar to bone mineral, develops on the surface of Bioglass 45S5. Collagen from the surrounding tissue is adsorbed on this layer that attracts osteoblasts, and favors bone regrowth. Bioglass is therefore an osteoinductive material. Still, due to its brittleness, the glass alone cannot be used to heal large bone defects. To overcome this issue, Bioglass is used to form a composite scaffold with poly(D,L-lactide) (PDLLA), a biodegradable polymer. The goal of this work is to understand Bioglass reactivity throughout scaffold fabrication via a low-temperature route, the solvent casting and particulate leaching technique. Changes in Bioglass (especially its surface) are susceptible to occur both while in contact with the processing fluids and potentially through a reaction with the surrounding polymeric matrix. Here we analyzed the surface changes of three different Bioglass samples: (i) as-received, (ii) treated in solutions that parallel those used in scaffold fabrication, and (iii) extracted from the scaffolds. We showed that extracted, just like treated, Bioglass deviates from the as-received, but to a larger extent. X-ray photoelectron and infrared spectroscopy support the theory that Bioglass surface was modified not just through contact with the solutions in scaffold fabrication, but upon an interaction with the polymeric matrix. The polymer network slows down the Na(+)/H(+) exchange between Bioglass and water used to leach salt particles to create pores within the scaffold. Changes in surface properties affect the bioactivity of Bioglass and thus of the composite scaffolds, and are therefore critical to identify. PMID:23305513

Abdollahi, Sara; Ma, Alvin Chih Chien; Cerruti, Marta

2013-01-24

279

In-situ sol-gel synthesis and characterization of bioactive pHEMA/SiO2 blend hybrids.  

PubMed

A novel procedure to synthesize poly(2-hydroxyethylmethacrylate)-silica blend hybrids is presented. Methacrylate monomers bearing an alkoxysilyl unit, prepared by Michael addition of 2-hydroxyethylmethacrylate (HEMA) to 3-Aminopropyltriethoxysilane (APTS) were employed. By (13)C NMR and mass analysis it was possible to establish the formation of coupling hybrid species. Hybrid materials, with final concentration ranging from 10% to 30% w/w of silica gel to the mass of polymer, were obtained through basic catalyzed sol-gel process of tetraethoxysilane (TEOS) and the alkoxysilyl unit of the hybrid monomer, followed by in-situ free-radical polymerization. The hybrids were characterized as far as concerns their thermal properties (glass transition temperature, decomposition temperature), their sorption behavior in water, and in-vitro bioactivity. Optical transparency, higher glass transition temperature, and higher decomposition temperature than pHEMA suggest an increase in either density or intensity of cross-links between the organic and the inorganic phases. The swelling ratio of the 30% hybrids is comparable to pHEMA, whereas it is lower for the other compositions. In-vitro bioactivity of the hybrids, due to the inorganic phase, was ascertained. Soaking time required for apatite deposition on the samples surface decreases as the content of silica gel increases. Therefore, the obtained bioactive hybrids can be used to make bioactive scaffolds for bone engineering. PMID:18823022

Silvestri, B; Luciani, G; Costantini, A; Tescione, F; Branda, F; Pezzella, A

2009-05-01

280

Biocompatible glass-ceramic materials for bone substitution.  

PubMed

A new bioactive glass composition (CEL2) in the SiO(2)-P(2)O(5)-CaO-MgO-K(2)O-Na(2)O system was tailored to control pH variations due to ion leaching phenomena when the glass is in contact with physiological fluids. CEL2 was prepared by a traditional melting-quenching process obtaining slices that were heat-treated to obtain a glass-ceramic material (CEL2GC) that was characterized thorough SEM analysis. Pre-treatment of CEL2GC with SBF was found to enhance its biocompatibility, as assessed by in vitro tests. CEL2 powder was then used to synthesize macroporous glass-ceramic scaffolds. To this end, CEL2 powders were mixed with polyethylene particles within the 300-600 microm size-range and then pressed to obtain crack-free compacted powders (green). This was heat-treated to remove the organic phase and to sinter the inorganic phase, leaving a porous structure. The biomaterial thus obtained was characterized by X-ray diffraction, SEM equipped with EDS, density measurement, image analysis, mechanical testing and in vitro evaluation, and found to be a glass-ceramic macroporous scaffold with uniformly distributed and highly interconnected porosity. The extent and size-range of the porosity can be tailored by varying the amount and size of the polyethylene particles. PMID:17607523

Vitale-Brovarone, Chiara; Verné, Enrica; Robiglio, Lorenza; Martinasso, Germana; Canuto, Rosa A; Muzio, Giuliana

2007-07-03

281

Novel antibacterial nanofibrous PLLA scaffolds  

Microsoft Academic Search

In order to achieve high local bioactivity and low systemic side effects of antibiotics in the treatment of dental, periodontal and bone infections, a localized and temporally controlled delivery system is crucial. In this study, a three-dimensional (3-D) porous tissue engineering scaffold was developed with the ability to release antibiotics in a controlled fashion for long-term inhibition of bacterial growth.

Kai Feng; Hongli Sun; Mark A. Bradley; Ellen J. Dupler; William V. Giannobile; Peter X. Ma

2010-01-01

282

Hydrogels for tissue engineering: scaffold design variables and applications  

Microsoft Academic Search

Polymer scaffolds have many different functions in the field of tissue engineering. They are applied as space filling agents, as delivery vehicles for bioactive molecules, and as three-dimensional structures that organize cells and present stimuli to direct the formation of a desired tissue. Much of the success of scaffolds in these roles hinges on finding an appropriate material to address

Jeanie L. Drury; David J. Mooney

2003-01-01

283

Multifunctional nanofibrous scaffold for tissue engineering  

Microsoft Academic Search

In tissue engineering, scaffolds with multiscale functionality, especially with the ability to release locally multiple or specific bioactive molecules to targeted cell types, are highly desired in regulating appropriate cell phenotypes. In this study, poly (epsilon-caprolactone) (PCL) solutions (8% w\\/v) containing different amounts of bovine serum albumin (BSA) with or without collagen were electrospun into nanofibres. As verified by protein

X. Yang; K. R. Ogbolu; H. Wang

2008-01-01

284

Scaffolding and Metacognition  

ERIC Educational Resources Information Center

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

Holton, Derek; Clarke, David

2006-01-01

285

Magnetic bioactive glass ceramic in the system CaO-P2O5-SiO2-MgO-CaF2-MnO2-Fe2O3 for hyperthermia treatment of bone tumor.  

PubMed

Magnetic bioactive glass ceramic (MG) in the system CaO-SiO(2)-P(2)O(5)-MgO-CaF(2)-MnO(2)-Fe(2)O(3) for hyperthermia treatment of bone tumor was synthesized. The phase composition was investigated by XRD. The magnetic property was measured by VSM. The in vitro bioactivity was investigated by simulated body fluid (SBF) soaking experiment. Cell growth on the surface of the material was evaluated by co-culturing osteoblast-like ROS17/2.8 cells with materials for 7 days. The results showed that MG contained CaSiO(3) and Ca(5)(PO(4))(3)F as the main phases, and MnFe(2)O(4) and Fe(3)O(4) as the magnetic phases. Under a magnetic field of 10,000 Oe, the saturation magnetization and coercive force of MG were 6.4 emu/g and 198 Oe, respectively. After soaking in SBF for 14 days, hydroxyapatite containing CO(3)(2-) was observed on the surface of MG. The experiment of co-culturing cells with material showed that cells could successfully attach and well proliferate on MG. PMID:21870083

Li, Guangda; Feng, Shuying; Zhou, Dali

2011-08-26

286

Novel bioactive functionally graded coatings on Ti6Al4V  

SciTech Connect

Bioactive glass coatings are very promising for implant materials due to their good adhesion, mechanical stability, and bioactivity. A new family of silicate-based glasses has been prepared and applied to metallic implants using a simple enameling technique. The graded approach used here reduces stress between layers, and preliminary indentation tests indicate a strong glass/metal adhesion.

Gomez-Vega, Jose M.; Saiz, E.; Tomsia, A.P.; Oku, T.; Suganuma, K.; Marshall, G.W.; Marshall, S.J.

2000-03-01

287

Sol-gel derived porous bioactive nanocomposites: Synthesis and in vitro bioactivity  

NASA Astrophysics Data System (ADS)

Porous bioactive composites consisting of SiO2-CaO-Na2O-P2O5 bioactive glass-ceramic and synthetic water soluble polymer Polyvinylpyrrolidone [PVP (C6H9NO)n, MW~40000 g/mol] have been synthesized by sol-gel route. As-prepared polymeric composites were characterized by X-ray diffraction (XRD) technique. Two major bone mineral phases, viz., hydroxyapatite [Ca10(PO4)6(OH)2] and wollastonite [calcium silicate (CaSiO3)] have been identified in the XRD patterns of the composites. Presence of these bone minerals indicates the bioactive nature of the composites. In vitro bioactivity tests confirm bioactivity in the porous composites. The flexibility offered by these bioactive polymer composites is advantageous for its application as implant material.

Shankhwar, Nisha; Kothiyal, G. P.; Srinivasan, A.

2013-06-01

288

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

PubMed

Controlling topographic features at all length scales is of great importance for the interaction of cells with tissue regenerative materials. We utilized an indirect three-dimensional printing method to fabricate polymeric scaffolds with pre-defined and controlled external and internal architecture that had an interconnected structure with macro- (400-500 ?m) and micro- (?25 ?m) porosity. Polycaprolactone (PCL) was used as model system to study the kinetics of tissue growth within porous scaffolds. The surface of the scaffolds was decorated with TiO2 and bioactive glass (BG) nanoparticles to the better match to nanoarchitecture of extracellular matrix (ECM). Micrometric BG particles were also used to reveal the effect of particle size on the cell behavior. Observation of tissue growth and enzyme activity on two-dimensional (2D) films and three-dimensional (3D) scaffolds showed effects of nanoparticle inclusion and of surface curvature on the cellular adhesion, proliferation, and kinetics of preosteoblastic cells (MC3T3-E1) tissue growth into the pore channels. It was found that the presence of nanoparticles in the substrate impaired cellular adhesion and proliferation in 3D structures. Evaluation of alkaline phosphate activity showed that the presence of the hard particles affects differentiation of the cells on 2D films. Notwithstanding, the effect of particles on cell differentiation was not as strong as that seen by the curvature of the substrate. We observed different effects of nanofeatures on 2D structures with those of 3D scaffolds, which influence the cell proliferation and differentiation for non-load-bearing applications in bone regenerative medicine. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:2796-2807, 2013. PMID:23463703

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

2013-03-05

289

Effect of partial crystallization on the mechanical properties and cytotoxicity of bioactive glass from the 3CaO.P(2)O(5)-SiO(2)-MgO system.  

PubMed

The aim of this study is to report on the development and characterization of bioactive glass and glass-ceramics from the 3CaO.P(2)O(5)-SiO(2)-MgO-system, using different degrees of cristallinity for applications as an implant material. A methodology was proposed to induce crystallization of phases. Bioglass samples of the nominal composition (wt %) 57.75 CaO.P(2)O(5)-30 SiO(2)-17.25MgO were heat treated at temperatures ranging from 700 to 1100°C for 4h. The findings from the research illustrate how partial crystallization and phase transformations modified the microstructure of the based glassy material, resulting in improved mechanical properties. The maximum gain was measured for samples treated at 975°C, having a hardness of 6.2GPa, an indentation fracture toughness of 1.7MPam(1/2) and a bending strength of 120MPa, representing an increase of 30, 55 and 70%, respectively, when compared to the nucleated glass. The highest elastic modulus of about 130GPa was determined for samples treated at 1100°C. As a preliminary biological evaluation, "in vitro" cytotoxicity tests were realized to determine the cytotoxic level of the materials, using the neutral red uptake method with NCTC clones L929 from the American Type Culture Collection (ATCC) bank. On the other hand, no significant influence of the partial crystallization on cytotoxicity was observed. The results provide support for implant materials based on the 3CaO.P(2)O(5)-SiO(2)-MgO-system. PMID:22975418

Daguano, J K M F; Strecker, K; Ziemath, E C; Rogero, S O; Fernandes, M H V; Santos, C

2012-05-14

290

Hybrid nanofibrous scaffolds from electrospinning of a synthetic biodegradable elastomer and urinary bladder matrix.  

PubMed

Synthetic materials can be electrospun into submicron or nanofibrous scaffolds to mimic extracellular matrix (ECM) scale and architecture with reproducible composition and adaptable mechanical properties. However, these materials lack the bioactivity present in natural ECM. ECM-derived scaffolds contain bioactive molecules that exert in vivo mimicking effects as applied for soft tissue engineering, yet do not possess the same flexibility in mechanical property control as some synthetics. The objective of the present study was to combine the controllable properties of a synthetic, biodegradable elastomer with the inherent bioactivity of an ECM derived scaffold. A hybrid electrospun scaffold composed of a biodegradable poly(ester-urethane)urea (PEUU) and a porcine ECM scaffold (urinary bladder matrix, UBM) was fabricated and characterized for its bioactive and physical properties both in vitro and in vivo. Increasing amounts of PEUU led to linear increases in both tensile strength and breaking strain while UBM incorporation led to increased in vitro smooth muscle cell adhesion and proliferation and in vitro mass loss. Subcutaneous implantation of the hybrid scaffolds resulted in increased scaffold degradation and a large cellular infiltrate when compared with electrospun PEUU alone. Electrospun UBM/PEUU combined the attractive bioactivity and mechanical features of its individual components to result in scaffolds with considerable potential for soft tissue engineering applications. PMID:18419942

Stankus, John J; Freytes, Donald O; Badylak, Stephen F; Wagner, William R

2008-01-01

291

Piezoelectric PU/PVDF electrospun scaffolds for wound healing applications.  

PubMed

Previous studies have shown that piezoelectric materials may be used to prepare bioactive electrically charged surfaces. In the current study, polyurethane/polyvinylidene fluoride (PU/PVDF) scaffolds were prepared by electrospinning. The mechanical property and piezoelectric property of the scaffolds were evaluated. The crystalline phase of PVDF in the scaffolds was characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). In vitro cell culture was performed to investigate cytocompatibility of the scaffolds. Wound-healing assay, cell-adhesion assay, quantitative RT-PCR and Western blot analyses were performed to investigate piezoelectric effect of the scaffolds on fibroblast activities. Further, the scaffolds were subcutaneously implanted in Sprague-Dawley (SD) rats to investigate their biocompatibility and the piezoelectric effect on fibrosis in vivo. The results indicated that the electrospinning process had changed PVDF crystalline phase from the nonpiezoelectric ? phase to the piezoelectric ? phase. The fibroblasts cultured on the scaffolds showed normal morphology and proliferation. The fibroblasts cultured on the piezoelectric-excited scaffolds showed enhanced migration, adhesion and secretion. The scaffolds that were subcutaneously implanted in SD rats showed higher fibrosis level due to the piezoelectrical stimulation, which was caused by random animal movements followed by mechanical deformation of the scaffolds. The scaffolds are potential candidates for wound healing applications. PMID:22503631

Guo, Hong-Feng; Li, Zhen-Sheng; Dong, Shi-Wu; Chen, Wei-Jun; Deng, Ling; Wang, Yu-Fei; Ying, Da-Jun

2012-03-29

292

In vitro bioactivity of glass–ceramics of the CaMgSi 2O 6–CaSiO 3–Ca 5(PO 4) 3F–Na 2SiO 3 system with TiO 2 or ZnO additives  

Microsoft Academic Search

Glass–ceramic materials based on diopside [CaMgSi2O6]–wollastonite [CaSiO3]–fluoroapatite [Ca5(PO4)3F]–sodium silicate [Na2SiO3] system with TiO2 or ZnO additives were successfully prepared and examined in vitro, by using a simulated body fluid (SBF) solution, to be suitable for restorative dental and bone implant materials. In vitro bioactivity of the glass–ceramics was examined by using scanning electron microscopy equipped with energy dispersive X-ray detectors

S. M. Salman; S. N. Salama; H. Darwish; H. A. Abo-Mosallam

2009-01-01

293

Bioactive Hydrogels  

NASA Astrophysics Data System (ADS)

There is much recent interest in the development of polymeric materials that go beyond the concept of biocompatibility, that is, that are capable of directing a particular desired biological response such as neovascularization. The approach described for the creation of bioactive surfaces involves the tethering of functional hydrogels to a polymeric substrate. The functional hydrogels are resistant to protein adsorption but are decorated with a variety of tissue response modifiers like growth factors and adhesion ligands that can induce a desired biological response. The hydrogel monomers must have controlled viscosity to be practically effective, so they are prepared by photoinitiated end-linking of end-functional macromonomers synthesized by atom transfer radical polymerization. The use of t-butyl methacrylate monomers allows for spatial photo-patterning of tissue response modifiers.

Koberstein, Jeffrey T.

2002-03-01

294

Electrospun silk-BMP-2 scaffolds for bone tissue engineering  

Microsoft Academic Search

Silk fibroin fiber scaffolds containing bone morphogenetic protein 2 (BMP-2) and\\/or nanoparticles of hydroxyapatite (nHAP) prepared via electrospinning were used for in vitro bone formation from human bone marrow-derived mesenchymal stem cells (hMSCs). BMP-2 survived the aqueous-based electrospinnig process in bioactive form. hMSCs were cultured for up to 31 days under static conditions in osteogenic media on the scaffolds (silk\\/PEO\\/BMP-2,

Chunmei Li; Charu Vepari; Hyoung-Joon Jin; Hyeon Joo Kim; David L. Kaplan

2006-01-01

295

Electrical properties of phosphate glasses  

NASA Astrophysics Data System (ADS)

Investigation of the electrical properties of phosphate glasses where transition metal oxide such as iron oxide is the network former and network modifier is presented. Phosphate glasses containing iron are electronically conducting glasses where the polaronic conduction is due to the electron hopping from low to high iron valence state. The identification of structural defects caused by ion/polaron migration, the analysis of dipolar states and electrical conductivity in iron phosphate glasses containing various alkali and mixed alkali ions was performed on the basis of the impedance spectroscopy (IS). The changes in electrical conductivity from as-quenched phosphate glass to fully crystallized glass (glass-ceramics) by IS are analyzed. A change in the characteristic features of IS follows the changes in glass and crystallized glass network. Using IS, the contribution of glass matrix, crystallized grains and grain boundary to the total electrical conductivity for iron phosphate glasses was analyzed. It was shown that decrease in conductivity is caused by discontinuities in the conduction pathways as a result of the disruption of crystalline network where two or more crystalline phases are formed. Also, phosphate-based glasses offer a unique range of biomaterials, as they form direct chemical bonding with hard/soft tissue. The surface charges of bioactive glasses are recognized to be the most important factors in determining biological responses. The improved bioactivity of the bioactive glasses as a result of the effects of the surface charges generated by electrical polarization is discussed.

Mogus-Milankovic, A.; Santic, A.; Reis, S. T.; Day, D. E.

2009-07-01

296

Nonviral Gene Delivery from Nonwoven Fibrous Scaffolds Fabricated by Interfacial Complexation of Polyelectrolytes  

Microsoft Academic Search

We investigated a novel nonwoven fibrous scaffold as a vehicle for delivery of DNA. Fibers were formed by polyelectrolyte complexation of water-soluble chitin and alginate, and PEI–DNA nanoparticles were encapsulated during the fiber drawing process. Nanoparticles released from the fibers over time retained their bioactivity and successfully transfected cells seeded on the scaffold in a sustained manner. Transgene expression in

Shawn H. Lim; I-Chien Liao; Kam W. Leong

2006-01-01

297

PHBV\\/PLLA-based composite scaffolds containing nano-sized hydroxyapatite particles for bone tissue engineering  

Microsoft Academic Search

Composite scaffolds made of PHBV\\/PLLA blends and nano-sized hydroxyapatite (HA) particles can be useful for bone tissue engineering as different blends of PHBV with PLLA should have higher degradation rates than PHBV itself and scaffolds containing bioactive HA particles will provide desired osteoconductivity. In this investigation, composite scaffolds were produced via an emulsion freezing\\/freeze-drying process and subsequently characterised using several

N. Sultana; M. Wang

2008-01-01

298

Long-term in vitro degradation of PDLLA/bioglass bone scaffolds in acellular simulated body fluid.  

PubMed

The long-term (600days) in vitro degradation of highly porous poly(D,L-lactide) (PDLLA)/Bioglass-filled composite foams developed for bone tissue engineering scaffolds has been investigated in simulated body fluid (SBF). Foams of ?93% porosity were produced by thermally induced phase separation (TIPS). The degradation profile for foams of neat PDLLA and the influence of Bioglass addition were comprehensively assessed in terms of changes in dimensional stability, pore morphology, weight loss, molecular weight and mechanical properties (dry and wet states). It is shown that the degradation process proceeded in several stages: (a) a quasi-stable stage, where water absorption and plasticization occurred together with weight loss due to Bioglass particle loss and dissolution, resulting in decreased wet mechanical properties; (b) a stage showing a slight increase in the wet mechanical properties and a moderate decrease in dimensions, with the properties remaining moderately constant until the onset of significant weight loss, whilst molecular weight continued to decrease; (c) an end stage of massive weight loss, disruption of the pore structure and the formation of blisters and embrittlement of the scaffold (evident on handling). The findings from this long-term in vitro degradation investigation underpin studies that have been and continue to be performed on highly porous poly(?-hydroxyesters) scaffolds filled with bioactive glasses for bone tissue engineering applications. PMID:20849987

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

2010-09-16

299

Development and application of inorganic bioactive ceramic nanocomposites for bone tissue remodeling  

Microsoft Academic Search

The objective of the article is to study the synthesis, animal tests and results of clinical applications of the newly proposed kind of bioactive ceramics for full bone tissue restoration—inorganic composites consisting of modified phosphate ceramics, bioactive glasses and bioactive glass-ceramic—so-called SYNTHETBONE materials. Regulation of the composition and structure of the composite can serve to adjust physicochemical and biological properties

V. Dubok; A. Shynkaruk; O. Atamanenko; V. Protcenko; V. Kindrat; E. Shynkaruk; V. Kischuk; E. Buzaneva

2010-01-01

300

Sustained release of vascular endothelial growth factor from mineralized poly(lactide-co-glycolide) scaffolds for tissue engineering.  

PubMed

Strategies to engineer bone tissue have focused on either: (1) the use of scaffolds for osteogenic cell transplantation or as conductive substrates for guided bone regeneration; or (2) release of inductive bioactive factors from these scaffold materials. This study describes an approach to add an inductive component to an osteoconductive scaffold for bone tissue engineering. We report the release of bioactive vascular endothelial growth factor (VEGF) from a mineralized, porous, degradable polymer scaffold. Three dimensional, porous scaffolds of the copolymer 85 : 15 poly(lactide-co-glycolide) were fabricated by including the growth factor into a gas foaming/particulate leaching process. The scaffold was then mineralized via incubation in a simulated body fluid. Growth of a bone-like mineral film on the inner pore surfaces of the porous scaffold is confirmed by mass increase measurements and quantification of phosphate content within scaffolds. Release of 125I-labeled VEGF was tracked over a 15 day period to determine release kinetics from the mineralized scaffolds. Sustained release from the mineralized scaffolds was achieved, and growth of the mineral film had only a minor effect on the release kinetics from the scaffolds. The VEGF released from the mineralized and non-mineralized scaffolds was over 70% active for up to 12 days following mineralization treatment, and the growth of mineral had little effect on total scaffold porosity. PMID:11071602

Murphy, W L; Peters, M C; Kohn, D H; Mooney, D J

2000-12-01

301

Investigation of fabrication and environmental effects on bioceramic bone scaffolds  

NASA Astrophysics Data System (ADS)

Bioactive ceramic materials like tricalcium phosphates (TCP) have been emerging as viable material alternatives to the current therapies of bone scaffolding to target fracture healing and osteoporosis. Once scaffolds are implanted at the defect site they should provide mechanical and biological functions, ultimately serving to facilitate with surrounding native tissue. Optimal osteogenic signal expression and subsequent differentiation of cells seeded on the scaffold in both in vivo and in vitro conditions is known to be influenced by scaffold properties and biomechanical environmental conditions. Thus, the objective of this research was to investigate the effect of fabrication and environmental variables on the properties of bioceramic scaffolds for bone tissue engineering applications. Specifically, the effect of sintering temperature in the range of 950°C -1150°C of a cost-effective on a large scale manufacturing process, on the physical and mechanical properties of bioceramic bone scaffolds, was investigated. In addition, the effect of a controlled environment was investigated by implementing a bioreactor and bone loading system to study the response of ex vivo trabecular bone to compressive load while perfused with culture medium. Collectively, this thesis demonstrates that: (1) the sintering temperature to fabricate bioceramic scaffolds can be tuned to structural properties, and (2) the use of a controlled mechanical and biochemical environment can enhance bone tissue development. These findings support the development of clinically successful bioceramic scaffolds that may stimulate bone regeneration and scaffold integration while providing structural integrity.

Vivanco Morales, Juan Francisco

302

Porous Allograft Bone Scaffolds: Doping with Strontium  

PubMed Central

Strontium (Sr) can promote the process of bone formation. To improve bioactivity, porous allograft bone scaffolds (ABS) were doped with Sr and the mechanical strength and bioactivity of the scaffolds were evaluated. Sr-doped ABS were prepared using the ion exchange method. The density and distribution of Sr in bone scaffolds were investigated by inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS). Controlled release of strontium ions was measured and mechanical strength was evaluated by a compressive strength test. The bioactivity of Sr-doped ABS was investigated by a simulated body fluid (SBF) assay, cytotoxicity testing, and an in vivo implantation experiment. The Sr molar concentration [Sr/(Sr+Ca)] in ABS surpassed 5% and Sr was distributed nearly evenly. XPS analyses suggest that Sr combined with oxygen and carbonate radicals. Released Sr ions were detected in the immersion solution at higher concentration than calcium ions until day 30. The compressive strength of the Sr-doped ABS did not change significantly. The bioactivity of Sr-doped material, as measured by the in vitro SBF immersion method, was superior to that of the Sr-free freeze-dried bone and the Sr-doped material did not show cytotoxicity compared with Sr-free culture medium. The rate of bone mineral deposition for Sr-doped ABS was faster than that of the control at 4 weeks (3.28±0.23 µm/day vs. 2.60±0.20 µm/day; p<0.05). Sr can be evenly doped into porous ABS at relevant concentrations to create highly active bone substitutes.

Zhao, Yantao; Guo, Dagang; Hou, Shuxun; Zhong, Hongbin; Yan, Jun; Zhang, Chunli; Zhou, Ying

2013-01-01

303

Porous allograft bone scaffolds: doping with strontium.  

PubMed

Strontium (Sr) can promote the process of bone formation. To improve bioactivity, porous allograft bone scaffolds (ABS) were doped with Sr and the mechanical strength and bioactivity of the scaffolds were evaluated. Sr-doped ABS were prepared using the ion exchange method. The density and distribution of Sr in bone scaffolds were investigated by inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS). Controlled release of strontium ions was measured and mechanical strength was evaluated by a compressive strength test. The bioactivity of Sr-doped ABS was investigated by a simulated body fluid (SBF) assay, cytotoxicity testing, and an in vivo implantation experiment. The Sr molar concentration [Sr/(Sr+Ca)] in ABS surpassed 5% and Sr was distributed nearly evenly. XPS analyses suggest that Sr combined with oxygen and carbonate radicals. Released Sr ions were detected in the immersion solution at higher concentration than calcium ions until day 30. The compressive strength of the Sr-doped ABS did not change significantly. The bioactivity of Sr-doped material, as measured by the in vitro SBF immersion method, was superior to that of the Sr-free freeze-dried bone and the Sr-doped material did not show cytotoxicity compared with Sr-free culture medium. The rate of bone mineral deposition for Sr-doped ABS was faster than that of the control at 4 weeks (3.28 ± 0.23 µm/day vs. 2.60 ± 0.20 µm/day; p<0.05). Sr can be evenly doped into porous ABS at relevant concentrations to create highly active bone substitutes. PMID:23922703

Zhao, Yantao; Guo, Dagang; Hou, Shuxun; Zhong, Hongbin; Yan, Jun; Zhang, Chunli; Zhou, Ying

2013-07-26

304

Bioactive Modification of Poly(ethylene glycol) Hydrogels for Tissue Engineering  

PubMed Central

In this review, we explore different approaches for introducing bioactivity into poly(ethylene glycol) (PEG) hydrogels. Hydrogels are excellent scaffolding materials for repairing and regenerating a variety of tissues because they can provide a highly swollen three-dimensional (3D) environment similar to soft tissues. Synthetic hydrogels like PEG-based hydrogels have advantages over natural hydrogels, such as the ability for photopolymerization, adjustable mechanical properties, and easy control of scaffold architecture and chemical compositions. However, PEG hydrogels alone cannot provide an ideal environment to support cell adhesion and tissue formation due to their bio-inert nature. The natural extracellular matrix (ECM) has been an attractive model for the design and fabrication of bioactive scaffolds for tissue engineering. ECM-mimetic modification of PEG hydrogels has emerged as an important strategy to modulate specific cellular responses. To tether ECM-derived bioactive molecules (BMs) to PEG hydrogels, various strategies have been developed for the incorporation of key ECM biofunctions, such as specific cell adhesion, proteolytic degradation, and signal molecule-binding. A number of cell types have been immobilized on bioactive PEG hydrogels to provide fundamental knowledge of cell/scaffold interactions. This review addresses the recent progress in material designs and fabrication approaches leading to the development of bioactive hydrogels as tissue engineering scaffolds.

Zhu, Junmin

2010-01-01

305

Macroporous nanowire nanoelectronic scaffolds for synthetic tissues  

NASA Astrophysics Data System (ADS)

The development of three-dimensional (3D) synthetic biomaterials as structural and bioactive scaffolds is central to fields ranging from cellular biophysics to regenerative medicine. As of yet, these scaffolds cannot electrically probe the physicochemical and biological microenvironments throughout their 3D and macroporous interior, although this capability could have a marked impact in both electronics and biomaterials. Here, we address this challenge using macroporous, flexible and free-standing nanowire nanoelectronic scaffolds (nanoES), and their hybrids with synthetic or natural biomaterials. 3D macroporous nanoES mimic the structure of natural tissue scaffolds, and they were formed by self-organization of coplanar reticular networks with built-in strain and by manipulation of 2D mesh matrices. NanoES exhibited robust electronic properties and have been used alone or combined with other biomaterials as biocompatible extracellular scaffolds for 3D culture of neurons, cardiomyocytes and smooth muscle cells. Furthermore, we show the integrated sensory capability of the nanoES by real-time monitoring of the local electrical activity within 3D nanoES/cardiomyocyte constructs, the response of 3D-nanoES-based neural and cardiac tissue models to drugs, and distinct pH changes inside and outside tubular vascular smooth muscle constructs.

Tian, Bozhi; Liu, Jia; Dvir, Tal; Jin, Lihua; Tsui, Jonathan H.; Qing, Quan; Suo, Zhigang; Langer, Robert; Kohane, Daniel S.; Lieber, Charles M.

2012-11-01

306

Development of high strength hydroxyapatite for bone tissue regeneration using nanobioactive glass composites  

NASA Astrophysics Data System (ADS)

With an increasing demand of biocompatible bone substitutes for the treatment of bone diseases and bone tissue regeneration, bioactive glass composites are being tested to improvise the osteoconductive as well as osteoinductive properties. Nanobioactive glass (nBG) composites, having composition of SiO2 70 mol%, CaO 26 mol % and P2O5 4 mol% were prepared by Freeze drying method using PEG-PPG-PEG co-polymer. Polymer addition improves the mechanical strength and porosity of the scaffold of nBG. Nano Bioactive glass composites upon implantation undergo specific reactions leading to the formation of crystalline hydroxyapatite (HA). This is tested in vitro using Simulated Body Fluid (SBF). This high strength hydroxyapatite (HA) layer acts as osteoconductive in cellular environment, by acting as mineral base of bones, onto which new bone cells proliferate leading to new bone formation. Strength of the nBG composites as well as HA is in the range of cortical and cancellous bone, thus proving significant for bone tissue regeneration substitutes.

Shrivastava, Pragya; Dalai, Sridhar; Sudera, Prerna; Sivam, Santosh Param; Vijayalakshmi, S.; Sharma, Pratibha

2013-02-01

307

Designing bioactive delivery systems for tissue regeneration.  

PubMed

The direct infusion of macromolecules into defect sites generally does not impart adequate physiological responses. Without the protection of delivery systems, inductive molecules may likely redistribute away from their desired locale and are vulnerable to degradation. In order to achieve efficacy, large doses supplied at interval time periods are necessary, often at great expense and ensuing detrimental side effects. The selection of a delivery system plays an important role in the rate of re-growth and functionality of regenerating tissue: not only do the release kinetics of inductive molecules and their consequent bioactivities need to be considered, but also how the delivery system interacts and integrates with its surrounding host environment. In the current review, we describe the means of release of macromolecules from hydrogels, polymeric microspheres, and porous scaffolds along with the selection and utilization of bioactive delivery systems in a variety of tissue-engineering strategies. PMID:20676773

Davis, Hillary E; Leach, J Kent

2010-07-30

308

Designing Bioactive Delivery Systems for Tissue Regeneration  

PubMed Central

The direct infusion of macromolecules into defect sites generally does not impart adequate physiological responses. Without the protection of delivery systems, inductive molecules may likely redistribute away from their desired locale and are vulnerable to degradation. In order to achieve efficacy, large doses supplied at interval time periods are necessary, often at great expense and ensuing detrimental side effects. The selection of a delivery system plays an important role in the rate of re-growth and functionality of regenerating tissue: not only do the release kinetics of inductive molecules and their consequent bioactivities need to be considered, but also how the delivery system interacts and integrates with its surrounding host environment. In the current review, we describe the means of release of macromolecules from hydrogels, polymeric microspheres, and porous scaffolds along with the selection and utilization of bioactive delivery systems in a variety of tissue-engineering strategies.

Davis, Hillary E.

2010-01-01

309

Synthesis and evaluation of novel glass ceramics as drug delivery systems in osteomyelitis.  

PubMed

In this study, a new generation of bioactive glass ceramics were developed using the wet chemical method. The synthetic conditions were strictly controlled to obtain the materials of a nanometric scale. As evaluated by scanning electron microscopy, bone-like apatite layers were produced in large amounts and completely covered their surfaces after immersion in phosphate buffer saline. On the basis of X-ray diffraction, X-ray fluorescence, and Fourier transform infrared spectroscopy results, PO?³? groups of hydroxyapatite (HA) were partially substituted by SiO??? species. The defective chemical structures introduced provided materials that were more biologically active, compared with the parent HA. For effective treatment of infected bones, scaffolds containing the bioactive ceramics were prepared by chitosan cross-linking, and loaded with vancomycin (VCM). The drug-loaded scaffolds were not toxic to bone cells. About 75%-80% of the entrapped drug was released in a controlled pattern and the release was sustained over a 12-day period. The concentration of drug released was determined to be above 20 times the half maximal effective concentration of VCM on Staphylococcus aureus, and was sufficient for killing bacteria growing as biofilm. In summary, the synthesized bioceramics exhibited many of properties associated with an ideal material for implantable drug delivery system, and were suitable for testing the ability to cure bone diseases including osteomyelitis. PMID:22674208

Thanyaphoo, Suphannee; Kaewsrichan, Jasadee

2012-06-06

310

Hybrid biomimetic scaffold composed of electrospun polycaprolactone nanofibers and self-assembled peptide amphiphile nanofibers  

PubMed Central

Nanofibrous electrospun poly (?-caprolactone) (ePCL) scaffolds have inherent structural advantages, but lack of bioactivity has limited their usefulness in biomedical applications. Thus, here we report the development of a hybrid, nanostructured, extracellular matrix (ECM) mimicking scaffold by a combination of ePCL nanofibers and self-assembled peptide amphiphile (PA) nanofibers. The PAs have ECM mimicking characteristics including a cell adhesive ligand (RGDS) and matrix metalloproteinase-2 (MMP-2) mediated degradable sites. TEM imaging verified successful PA self-assembly into nanofibers (diameters of 8 – 10 nm) using a solvent evaporation method. This evaporation coating method was then used to successfully coat PAs onto ePCL nanofibers (diameters of 300 – 400 nm), to develop the hybrid, bioactive scaffolds. SEM characterization showed that the PA coatings did not interfere with the porous ePCL nanofiber network. Human mesenchymal stem cells (hMSCs) were seeded onto the hybrid scaffolds to evaluate their bioactivity. Significantly greater attachment and spreading of hMSCs were observed on ePCL nanofibers coated with PA-RGDS as compared to ePCL nanofibers coated with PA-S (no cell adhesive ligand) and uncoated ePCL nanofibers. Overall, this novel strategy presents a new solution to overcome the current bioactivity challenges of electrospun scaffolds and combines the unique characteristics of ePCL nanofibers and self-assembled PA nanofibers to provide an ECM mimicking environment. This has great potential to be applied to many different electrospun scaffolds for various biomedical applications.

Tambralli, Ajay; Blakeney, Bryan; Anderson, Joel; Kushwaha, Meenakshi; Andukuri, Adinarayana; Dean, Derrick; Jun, Ho-Wook

2011-01-01

311

The development of biocomposite nanofibers for tissue scaffolding applications  

NASA Astrophysics Data System (ADS)

The last decade has seen significant progress in the production of nanofibers by electrospinning. One of the major drivers to this progress is the potential use of nanofibrous structures as scaffolds for engineering tissues in regenerative medicine. Electrospun fibers are capable of emulating the nanofibrous architecture of the native extracellular matrix. They can potentially provide in-vivo-like nanomechanical and physicochemical signaling cues to the cells to establish apposite cell-scaffold interactions and promote functional changes between and within cells toward synthesis of a genuine extracellular matrix over time. In this context, this paper presents a brief overview of a scaffold design strategy. It also presents recent research pertaining to developing biomimetic and bioactive nanofibrous tissue scaffolds through electrospinning biocomposite nanofibers of organic-organic and inorganic-organic hybrids, which are potentially applicable to soft and hard tissue engineering.

Zhang, Y. Z.; Lim, C. T.

2008-06-01

312

Scaffolding for Software Renovation  

Microsoft Academic Search

We discuss an approach that explores the use of scaffoldingof source code to facilitate its renovation. We show thatscaffolding is a useful paradigm for software renovation. Wedesigned syntax and semantics for scaffolding, that enablesall relevant applications of scaffolding. The automatic generationof extensions to a normal grammar, so that the resultingextension grammar can parse code with scaffolding,is discussed. We used the

M. P. A. Sellink; Chris Verhoef

2000-01-01

313

Evaluation of osteoconductive scaffolds in the canine femoral multi-defect model.  

PubMed

Treatment of large segmental bone defects remains an unsolved clinical challenge, despite a wide array of existing bone graft materials. This project was designed to rapidly assess and compare promising biodegradable osteoconductive scaffolds for use in the systematic development of new bone regeneration methodologies that combine scaffolds, sources of osteogenic cells, and bioactive scaffold modifications. Promising biomaterials and scaffold fabrication methods were identified in laboratories at Rutgers, MIT, Integra Life Sciences, and Mayo Clinic. Scaffolds were fabricated from various materials, including poly(L-lactide-co-glycolide) (PLGA), poly(L-lactide-co-?-caprolactone) (PLCL), tyrosine-derived polycarbonate (TyrPC), and poly(propylene fumarate) (PPF). Highly porous three-dimensional (3D) scaffolds were fabricated by 3D printing, laser stereolithography, or solvent casting followed by porogen leaching. The canine femoral multi-defect model was used to systematically compare scaffold performance and enable selection of the most promising substrate(s) on which to add cell sourcing options and bioactive surface modifications. Mineralized cancellous allograft (MCA) was used to provide a comparative reference to the current clinical standard for osteoconductive scaffolds. Percent bone volume within the defect was assessed 4 weeks after implantation using both MicroCT and limited histomorphometry. Bone formed at the periphery of all scaffolds with varying levels of radial ingrowth. MCA produced a rapid and advanced stage of bone formation and remodeling throughout the defect in 4 weeks, greatly exceeding the performance of all polymer scaffolds. Two scaffold constructs, TyrPC(PL)/TCP and PPF4(SLA)/HA(PLGA) (Dip), proved to be significantly better than alternative PLGA and PLCL scaffolds, justifying further development. MCA remains the current standard for osteoconductive scaffolds. PMID:23215980

Luangphakdy, Viviane; Walker, Esteban; Shinohara, Kentaro; Pan, Hui; Hefferan, Theresa; Bauer, Thomas W; Stockdale, Linda; Saini, Sunil; Dadsetan, Mahrokh; Runge, M Brett; Vasanji, Amit; Griffith, Linda; Yaszemski, Michael; Muschler, George F

2013-03-01

314

Diamond as a scaffold for bone growth.  

PubMed

Diamond is an attractive material for biomedical implants. In this work, we investigate its capacity as a bone scaffold. It is well established that the bioactivity of a material can be evaluated by examining its capacity to form apatite-like calcium phosphate phases on its surface when exposed to simulated body fluid. Accordingly, polycrystalline diamond (PCD) and ultrananocrystalline diamond (UNCD) deposited by microwave plasma chemical vapour deposition were exposed to simulated body fluid and assessed for apatite growth when compared to the bulk silicon. Scanning electron microscopy and X-ray photoelectron spectroscopy showed that both UNCD and PCD are capable of acting as a bone scaffold. The composition of deposited apatite suggests that UNCD and PCD are suitable for in vivo implantation with UNCD possible favoured in applications where rapid osseointegration is essential. PMID:23386207

Fox, Kate; Palamara, Joseph; Judge, Roy; Greentree, Andrew D

2013-02-06

315

Biological diversity from a structurally diverse library: systematically scanning conformational space using a pyranose scaffold.  

PubMed

Success in discovering bioactive peptide mimetics is often limited by the difficulties in correctly transposing known binding elements of the active peptide onto a small and metabolically more stable scaffold while maintaining bioactivity. Here we describe a scanning approach using a library of pyranose-based peptidomimetics that is structurally diverse in a systematic manner, designed to cover all possible conformations of tripeptide motifs containing two aromatic groups and one positive charge. Structural diversity was achieved by efficient selection of various chemoforms, characterized by a choice of pyranose scaffold of defined chirality and substitution pattern. A systematic scanning library of 490 compounds was thus designed, produced, and screened in vitro for activity at the somatostatin (sst(1-5)) and melanin-concentrating hormone (MCH(1)) receptors. Bioactive compounds were found for each target, with specific chemoform preferences identified in each case, which can be used to guide follow-on drug discovery projects without the need for scaffold hopping. PMID:20684600

Abbenante, Giovanni; Becker, Bernd; Blanc, Sébastien; Clark, Chris; Condie, Glenn; Fraser, Graeme; Grathwohl, Matthias; Halliday, Judy; Henderson, Senka; Lam, Ann; Liu, Ligong; Mann, Maretta; Muldoon, Craig; Pearson, Andrew; Premraj, Rajaratnam; Ramsdale, Tracie; Rossetti, Tony; Schafer, Karl; Le Thanh, Giang; Tometzki, Gerald; Vari, Frank; Verquin, Géraldine; Waanders, Jennifer; West, Michael; Wimmer, Norbert; Yau, Annika; Zuegg, Johannes; Meutermans, Wim

2010-08-12

316

Drug-releasing scaffolds fabricated from drug-loaded microspheres.  

PubMed

Biodegradable scaffolds serve a central role in many strategies for engineering tissue replacements or in guiding tissue regeneration. Typically, these scaffolds function to create and maintain a space and to provide a support for cell adhesion. However, these scaffolds also can serve as vehicles for the delivery of bioactive factors (e.g., protein or DNA) in order to manipulate cellular processes within the scaffold microenvironment. This study presents a novel approach to fabricate tissue-engineering scaffolds capable of sustained drug delivery whereby drug-loaded microspheres are fabricated into structures with controlled porosity. A double-emulsion process was used to fabricate microspheres with encapsulated DNA that retained its integrity and was released from the microspheres within 24 h. These DNA-loaded microspheres subsequently were formed into a nonporous disk or an interconnected open-pore scaffold (>94% porosity) via a gas-foaming process. The disks and scaffolds exhibited sustained plasmid release for at least 21 days and had minimal burst during the initial phase of release. This approach of assembling drug-loaded microspheres into porous and nonporous structures may find great utility in the fabrication of synthetic matrices that direct tissue formation. PMID:11745572

Nof, Moriah; Shea, Lonnie D

2002-02-01

317

Case studies of the synthesis of bioactive cyclodepsipeptide natural products.  

PubMed

Cyclodepsipeptide natural products often display intriguing biological activities that along with their complex molecular scaffolds, makes them interesting targets for chemical synthesis. Although cyclodepsipeptides feature highly diverse chemical structures, their synthesis is often associated with similar synthetic challenges such as the establishment of a suitable macrocyclization methodology. This review therefore compiles case studies of synthetic approaches to different bioactive cyclodepsipeptide natural products, thereby illustrating obstacles of cyclodepsipeptide synthesis as well as their overcomings. PMID:23348990

Stolze, Sara C; Kaiser, Markus

2013-01-24

318

Polycaprolactone nanofiber interspersed collagen type-I scaffold for bone regeneration: a unique injectable osteogenic scaffold.  

PubMed

There is an increasing demand for an injectable cell coupled three-dimensional (3D) scaffold to be used as bone fracture augmentation material. To address this demand, a novel injectable osteogenic scaffold called PN-COL was developed using cells, a natural polymer (collagen type-I), and a synthetic polymer (polycaprolactone (PCL)). The injectable nanofibrous PN-COL is created by interspersing PCL nanofibers within pre-osteoblast cell embedded collagen type-I. This simple yet novel and powerful approach provides a great benefit as an injectable bone scaffold over other non-living bone fracture stabilization polymers, such as polymethylmethacrylate and calcium content resin-based materials. The advantages of injectability and the biomimicry of collagen was coupled with the structural support of PCL nanofibers, to create cell encapsulated injectable 3D bone scaffolds with intricate porous internal architecture and high osteoconductivity. The effects of PCL nanofiber inclusion within the cell encapsulated collagen matrix has been evaluated for scaffold size retention and osteocompatibility, as well as for MC3T3-E1 cells osteogenic activity. The structural analysis of novel bioactive material proved that the material is chemically stable enough in an aqueous solution for an extended period of time without using crosslinking reagents, but it is also viscous enough to be injected through a syringe needle. Data from long-term in vitro proliferation and differentiation data suggests that novel PN-COL scaffolds promote the osteoblast proliferation, phenotype expression, and formation of mineralized matrix. This study demonstrates for the first time the feasibility of creating a structurally competent, injectable, cell embedded bone tissue scaffold. Furthermore, the results demonstrate the advantages of mimicking the hierarchical architecture of native bone with nano- and micro-size formation through introducing PCL nanofibers within macron-size collagen fibers and in promoting osteoblast phenotype progression for bone regeneration. PMID:23804651

Baylan, Nuray; Bhat, Samerna; Ditto, Maggie; Lawrence, Joseph G; Lecka-Czernik, Beata; Yildirim-Ayan, Eda

2013-06-27

319

Fabrication of fibrinogen/P(LLA-CL) hybrid nanofibrous scaffold for potential soft tissue engineering applications.  

PubMed

Coelectrospinning of native proteins and elastic synthetic polymers is an attractive technique to fabricate hybrid fibrous scaffolds that combine the bioactivity and mechanical features of each material component. In this study, hybrid fibrous scaffolds composed of synthetic P(LLA-CL) elastomeric and naturally derived fibrinogen protein were fabricated and characterized for their bioactive and physiochemical properties. Fiber diameters of hybrid scaffolds increased with increasing P(LLA-CL) content, and the shape of fibers changed from cylindrical shape on pure polymer scaffolds to flat structure on hybrid scaffolds. Characterizations of ATR-FTIR, XRD, and thermal properties indicated that the hybrid scaffolds contain two different phases, one composed of pure fibrinogen and the other corresponding to a mixture of fibrinogen and P(LLA-CL), and no obvious chemical reaction takes place between two components. The hybrid fibrous scaffolds showed tailorable degradation rates than pure P(LLA-CL) and higher mechanical properties than pure fibrinogen, and both tensile strength and breaking strain increased with increasing P(LLA-CL) content. In Vitro studies revealed that L929 cells on hybrid scaffolds achieved relatively higher level of cell attachment after 12 h of culture and significant increased cell proliferation rate after 7 days of culture, when compared with pure fibrinogen and P(LLA-CL) scaffolds, and the cells exhibited a spreading polygonal shape on the hybrid fibrous surfaces compared to a round shape on surfaces of pure polymer scaffolds. Therefore, the fibrinogen/P(LLA-CL) hybrid fibrous scaffolds possess the combined benefits of each individual component, which make it capable as scaffolds for soft tissue reconstruction. PMID:21465642

He, Chuanglong; Xu, Xiaohong; Zhang, Fan; Cao, Lijun; Feng, Wei; Wang, Hongsheng; Mo, Xiumei

2011-04-04

320

Biodegradable polylactic acid microstructures for scaffold applications  

Microsoft Academic Search

In this research, we present a simple and cost effective soft lithographic process to fabricate polylactic acid (PLA) scaffolds\\u000a for tissue engineering. In which, the negative photoresist JSR THB-120N was spun on a glass subtract followed by conventional\\u000a UV lithographic processes to fabricate the master to cast the PDMS elastomeric mold. A thin poly(vinyl alcohol) (PVA) layer\\u000a was used as

Gou-Jen Wang; Kuan-Hsuan Ho; Cheng-Chih Hsueh

2008-01-01

321

Effects of Osteoblast-Like Cell Seeding on Mechanical Properties of Porous Composite Scaffolds  

Microsoft Academic Search

\\u000a Recently, much attention has been paid to the application of tissue engineering technology to bone regeneration. Bio-polymers\\u000a such as collagen and bioactive ceramics such as hydroxyapatite and tricalcium phosphates are used as raw materials for the\\u000a scaffolds for in vitro regeneration of bone tissue. These materials have been used to develop the scaffolds independently\\u000a but also polymer-ceramics or polymer-polymer composites

Takaaki Arahira; Mitsugu Todo

322

HA/nylon 6,6 porous scaffolds fabricated by salt-leaching/solvent casting technique: effect of nano-sized filler content on scaffold properties  

PubMed Central

Nanohydroxyapatite (n-HA)/nylon 6,6 composite scaffolds were produced by means of the salt-leaching/solvent casting technique. NaCl with a distinct range size was used with the aim of optimizing the pore network. Composite powders with different n-HA contents (40%, 60%) for scaffold fabrication were synthesized and tested. The composite scaffolds thus obtained were characterized for their microstructure, mechanical stability and strength, and bioactivity. The microstructure of the composite scaffolds possessed a well-developed interconnected porosity with approximate optimal pore size ranging from 200 to 500 ?m, ideal for bone regeneration and vascularization. The mechanical properties of the composite scaffolds were evaluated by compressive strength and modulus tests, and the results confirmed their similarity to cortical bone. To characterize bioactivity, the composite scaffolds were immersed in simulated body fluid for different lengths of time and results monitored by scanning electron microscopy and energy dispersive X-ray microanalysis to determine formation of an apatite layer on the scaffold surface.

Mehrabanian, Mehran; Nasr-Esfahani, Mojtaba

2011-01-01

323

Controlled release of IGF-1 and HGF from a biodegradable polyurethane scaffold  

PubMed Central

Purpose Biodegradable elastomers, which can possess favorable mechanical properties and degradation rates for soft tissue engineering applications, are more recently being explored as depots for biomolecule delivery. The objective of this study was to synthesize and process biodegradable, elastomeric poly(ester urethane)urea (PEUU) scaffolds and to characterize their ability to incorporate and release bioactive insulin-like growth factor–1 (IGF-1) and hepatocyte growth factor (HGF). Methods Porous PEUU scaffolds made from either 5 or 8 wt% PEUU were prepared with direct growth factor incorporation. Long-term in vitro IGF-1 release kinetics were investigated in saline or saline with 100 units/ml lipase to simulate in vivo degradation. Cellular assays were used to confirm released IGF-1 and HGF bioactivity. Results IGF-1 release into saline occurred in a complex multi-phasic manner for up to 440 days. Scaffolds generated from 5 wt% PEUU delivered protein faster than 8 wt% scaffolds. Lipase-accelerated scaffold degradation lead to delivery of >90% protein over 9 weeks for both polymer concentrations. IGF-1 and HGF bioactivity in the first 3 weeks was confirmed. Conclusions The capacity of a biodegradable elastomeric scaffold to provide long-term growth factor delivery was demonstrated. Such a system might provide functional benefit in cardiovascular and other soft tissue engineering applications.

Nelson, Devin M.; Baraniak, Priya R.; Ma, Zuwei; Guan, Jianjun; Mason, N. Scott; Wagner, William R.

2011-01-01

324

Nanofibrous architecture of silk fibroin scaffolds prepared with a mild self-assembly process.  

PubMed

Besides excellent biocompatibility and biodegradability, a useful tissue engineering scaffold should provide suitable macropores and nanofibrous structure, similar to extracellular matrix (ECM), to induce desired cellular activities and to guide tissue regeneration. In the present study, a mild process to prepare porous and nanofibrous silk-based scaffolds from aqueous solution is described. Using collagen to control the self-assembly of silk, nanofibrous silk scaffolds were firstly achieved through lyophilization. Water annealing was used to generate insolubility in the silk-based scaffolds, thereby avoiding the use of organic solvents. The nano-fibrils formed in the silk-collagen scaffolds had diameters of 20-100 nm, similar with native collagen in ECM. The silk-collagen scaffolds dissolved slowly in PBS solution, with about a 28% mass lost after 4 weeks. Following the dissolution or degradation, the nanofibrous structure inside the macropore walls emerged and interacted with cells directly. During in vitro cell culture, the nanofibrous silk-collagen scaffolds containing 7.4% collagen demonstrated significantly improved cell compatibility when compared with salt-leached silk scaffolds and silk-collagen scaffolds containing 20% collagen that emerged less nano-fibrils. Therefore, this new process provides useful scaffolds for tissue engineering applications. Furthermore, the process involves all-aqueous, room temperature and pressure processing without the use of toxic chemicals or solvents, offering new green chemistry approaches, as well as options to load bioactive drugs or growth factors into process. PMID:20970185

Lu, Qiang; Wang, Xiuli; Lu, Shenzhou; Li, Mingzhong; Kaplan, David L; Zhu, Hesun

2010-10-20

325

Novel polypyrrole-coated polylactide scaffolds enhance adipose stem cell proliferation and early osteogenic differentiation.  

PubMed

An electrically conductive polypyrrole (PPy) doped with a bioactive agent is an emerging functional biomaterial for tissue engineering. We therefore used chondroitin sulfate (CS)-doped PPy coating to modify initially electrically insulating polylactide resulting in novel osteogenic scaffolds. In situ chemical oxidative polymerization was used to obtain electrically conductive PPy coating on poly-96L/4D-lactide (PLA) nonwoven scaffolds. The coated scaffolds were characterized and their electrical conductivity was evaluated in hydrolysis. The ability of the coated and conductive scaffolds to enhance proliferation and osteogenic differentiation of human adipose stem cells (hASCs) under electrical stimulation (ES) in three-dimensional (3D) geometry was compared to the noncoated PLA scaffolds. Electrical conductivity of PPy-coated PLA scaffolds (PLA-PPy) was evident at the beginning of hydrolysis, but decreased during the first week of incubation due to de-doping. PLA-PPy scaffolds enhanced hASC proliferation significantly compared to the plain PLA scaffolds at 7 and 14 days. Furthermore, the alkaline phosphatase (ALP) activity of the hASCs was generally higher in PLA-PPy seeded scaffolds, but due to patient variation, no statistical significance could be determined. ES did not have a significant effect on hASCs. This study highlights the potential of novel PPy-coated PLA scaffolds in bone tissue engineering. PMID:23126228

Pelto, Jani; Björninen, Miina; Pälli, Aliisa; Talvitie, Elina; Hyttinen, Jari; Mannerström, Bettina; Suuronen Seppanen, Riitta; Kellomäki, Minna; Miettinen, Susanna; Haimi, Suvi

2013-01-04

326

The effect of nanofibrous galactosylated chitosan scaffolds on the formation of rat primary hepatocyte aggregates and the maintenance of liver function  

Microsoft Academic Search

Liver tissue engineering requires a perfect extracellular matrix (ECM) for primary hepatocytes culture to maintain high level of liver-specific functions and desirable mechanical stability. The aim of this study was to develop a novel natural nanofibrous scaffold with surface-galactose ligands to enhance the bioactivity and mechanical stability of primary hepatocytes in culture. The nanofibrous scaffold was fabricated by electrospinning a

Zhang-Qi Feng; Xuehui Chu; Ning-Ping Huang; Tao Wang; Yichun Wang; Xiaolei Shi; Yitao Ding; Zhong-Ze Gu

2009-01-01

327

A novel porcine acellular dermal matrix scaffold used in periodontal regeneration  

PubMed Central

Regeneration of periodontal tissue is the most promising method for restoring periodontal structures. To find a suitable bioactive three-dimensional scaffold promoting cell proliferation and differentiation is critical in periodontal tissue engineering. The objective of this study was to evaluate the biocompatibility of a novel porcine acellular dermal matrix as periodontal tissue scaffolds both in vitro and in vivo. The scaffolds in this study were purified porcine acellular dermal matrix (PADM) and hydroxyapatite-treated PADM (HA-PADM). The biodegradation patterns of the scaffolds were evaluated in vitro. The biocompatibility of the scaffolds in vivo was assessed by implanting them into the sacrospinal muscle of 20 New Zealand white rabbits. The hPDL cells were cultured with PADM or HA-PADM scaffolds for 3, 7, 14, 21 and 28 days. Cell viability assay, scanning electron microscopy (SEM), hematoxylin and eosin (H&E) staining, immunohistochemistry and confocal microscopy were used to evaluate the biocompatibility of the scaffolds. In vitro, both PADM and HA-PADM scaffolds displayed appropriate biodegradation pattern, and also, demonstrated favorable tissue compatibility without tissue necrosis, fibrosis and other abnormal response. The absorbance readings of the WST-1 assay were increased with the time course, suggesting the cell proliferation in the scaffolds. The hPDL cells attaching, spreading and morphology on the surface of the scaffold were visualized by SEM, H&E staining, immnuohistochemistry and confocal microscopy, demonstrated that hPDL cells were able to grow into the HA-PADM scaffolds and the amount of cells were growing up in the course of time. This study proved that HA-PADM scaffold had good biocompatibility in animals in vivo and appropriate biodegrading characteristics in vitro. The hPDL cells were able to proliferate and migrate into the scaffold. These observations may suggest that HA-PADM scaffold is a potential cell carrier for periodontal tissue regeneration.

Guo, Jing; Chen, Hui; Wang, Ying; Cao, Cheng-Bo; Guan, Guo-Qiang

2013-01-01

328

Selective adhesion and growth of vascular endothelial cells on bioactive peptide nanofiber functionalized stainless steel surface  

Microsoft Academic Search

Metal-based scaffolds such as stents are the most preferred treatment methods for coronary artery disease. However, impaired endothelialization on the luminal surface of the stents is a major limitation occasionally leading to catastrophic consequences in the long term. Coating the stent surface with relevant bioactive molecules is considered to aid in recovery of endothelium around the wound site. However, this

Hakan Ceylan; Ayse B. Tekinay; Mustafa O. Guler

2011-01-01

329

Bioactive silicate nanoplatelets for osteogenic differentiation of human mesenchymal stem cells.  

PubMed

Novel silicate nanoplatelets that induce osteogenic differentiation of human mesenchymal stem cells (hMSCs) in the absence of any osteoinductive factor are reported. The presence of the silicate triggers a set of events that follows the temporal pattern of osteogenic differentiation. These findings underscore the potential applications of these silicate nanoplatelets in designing bioactive scaffolds for musculoskeletal tissue engineering. PMID:23670944

Gaharwar, Akhilesh K; Mihaila, Silvia M; Swami, Archana; Patel, Alpesh; Sant, Shilpa; Reis, Rui L; Marques, Alexandra P; Gomes, Manuela E; Khademhosseini, Ali

2013-05-13

330

Application of Bioactive Molecules in Pulp-capping Situations  

Microsoft Academic Search

To evaluate the effects of bioactive molecules in pulpal wound healing, we carried out experiments using the rat upper molars as an in vivo model. Cavities were prepared on the mesial aspect, and pulp perforation was accomplished by the application of pressure with the tip of a steel probe. After the pulp-capping procedure, the cavities were filled with a glass-ionomer

M. Goldberg; F. Decup; D. Buch; E. Soheili Majd; J.-J. Lasfargues; E. Salih; L. Stanislawski

2001-01-01

331

Scaffolding: A Broader View.  

ERIC Educational Resources Information Center

|This commentary on C. Addison Stone's paper on the scaffolding metaphor for the learning disabilities field identifies issues in the metaphor's use and concludes that effective special education has been inhibited by isolation of interventions from theory and by the way teacher education is structured. Use of the scaffolding metaphor to refocus…

Reid, D. Kim

1998-01-01

332

3D Bone tissue engineered with bioactive microspheres in simulated microgravity  

Microsoft Academic Search

Summary  Three-dimensional (3D) osteoblast cell cultures were obtained in rotating-wall vessels (RWV), simulating microgravity. Three\\u000a types of bioactive microcarriers, specifically modified bioactive glass particles, bioceramic hollow microspheres, and biodegradable\\u000a bioactive glass-polymer composite microspheres, were developed and used with osteblasts. The surfaces of composite microspheres\\u000a fully transformed into bone apatite after 2-wk immersion in simulated physiological fluid, which demonstrated their bone-bonding\\u000a ability.

Qing-Qing Qiu; Paul Ducheyne; Portonovo S. Ayyaswamy

2001-01-01

333

Scaffolds for dental pulp tissue engineering.  

PubMed

For tissue engineering strategies, the choice of an appropriate scaffold is the first and certainly a crucial step. A vast variety of biomaterials is available: natural or synthetic polymers, extracellular matrix, self-assembling systems, hydrogels, or bioceramics. Each material offers a unique chemistry, composition and structure, degradation profile, and possibility for modification. The role of the scaffold has changed from passive carrier toward a bioactive matrix, which can induce a desired cellular behavior. Tailor-made materials for specific applications can be created. Recent approaches to generate dental pulp rely on established materials, such as collagen, polyester, chitosan, or hydroxyapatite. Results after transplantation show soft connective tissue formation and newly generated dentin. For dentin-pulp-complex engineering, aspects including vascularization, cell-matrix interactions, growth-factor incorporation, matrix degradation, mineralization, and contamination control should be considered. Self-assembling peptide hydrogels are an example of a smart material that can be modified to create customized matrices. Rational design of the peptide sequence allows for control of material stiffness, induction of mineral nucleation, or introduction of antibacterial activity. Cellular responses can be evoked by the incorporation of cell adhesion motifs, enzyme-cleavable sites, and suitable growth factors. The combination of inductive scaffold materials with stem cells might optimize the approaches for dentin-pulp complex regeneration. PMID:21677088

Galler, K M; D'Souza, R N; Hartgerink, J D; Schmalz, G

2011-07-01

334

In vitro and in vivo evaluation of adenovirus combined silk fibroin scaffolds for BMP-7 gene delivery.  

PubMed

Abstract Introduction and aims: For a scaffold material to be considered effective and efficient for tissue engineering it must be biocompatible as well as bioinductive. Silk fiber is a natural biocompatible material suitable for scaffold fabrication; however, silk is tissue-conductive and lacks tissue-inductive properties. One proposed method to make the scaffold tissue-inductive is to introduce plasmids or viruses encoding a specific growth factor into the scaffold. In this study, we constructed adenoviruses encoding bone morphogenetic protein-7 (BMP-7) and incorporated these into silk scaffolds. The osteo-inductive and new bone formation properties of these constructs were assessed in vivo in a critical-sized skull defect animal model. Materials and methods: Silk fibroin scaffolds containing adenovirus particles coding BMP-7 were prepared. The release of the adenovirus particles from the scaffolds was quantified by tissue-culture infective dose (TCID50) and the bioactivity of the released viruses was evaluated on human bone marrow mesenchymal stromal cells (BMSCs). To demonstrate the in vivo bone forming ability of the virus-carrying silk fibroin scaffold, the scaffold constructs were implanted into calvarial defects in SCID mice. Results: In vitro studies demonstrated that the virus-carrying silk fibroin scaffold released virus particles over a 3 week period while preserving their bioactivity. In vivo test of the scaffold constructs in critical-sized skull defect areas revealed that silk scaffolds were capable of delivering the adenovirus encoding BMP-7, resulting significantly enhanced new bone formation. Conclusions: Silk scaffolds carrying BMP-7 encoding adenoviruses can effectively transfect cells and enhance both in vitro and in vivo osteogenesis. The findings of this study indicate silk fibroin is a promising biomaterial for gene delivery to repair critical-sized bone defects. PMID:21417715

Zhang, Yufeng; Fan, Wei; Nothdurft, Luke; Wu, Chengtie; Zhou, Yinghong; Crawford, Ross; Xiao, Yin

2011-03-18

335

Nonviral Gene Delivery from Nonwoven Fibrous Scaffolds Fabricated by Interfacial Complexation of Polyelectrolytes  

PubMed Central

We investigated a novel nonwoven fibrous scaffold as a vehicle for delivery of DNA. Fibers were formed by polyelectrolyte complexation of water-soluble chitin and alginate, and PEI–DNA nanoparticles were encapsulated during the fiber drawing process. Nanoparticles released from the fibers over time retained their bioactivity and successfully transfected cells seeded on the scaffold in a sustained manner. Transgene expression in HEK293 cells and human dermal fibroblasts seeded on the transfecting scaffolds was significant even after 2 weeks of culture compared to 3-day expression in two-dimensional controls. Fibroblasts seeded on scaffolds containing DNA encoding basic fibroblast growth factor (bFGF) demonstrated prolonged secretion of bFGF at levels significantly higher than baseline. This work establishes the potential of this fibrous scaffold as a matrix capable of delivering genes to direct and support cellular development in tissue engineering.

Lim, Shawn H.; Liao, I-Chien; Leong, Kam W.

2008-01-01

336

Nonviral gene delivery from nonwoven fibrous scaffolds fabricated by interfacial complexation of polyelectrolytes.  

PubMed

We investigated a novel nonwoven fibrous scaffold as a vehicle for delivery of DNA. Fibers were formed by polyelectrolyte complexation of water-soluble chitin and alginate, and PEI-DNA nanoparticles were encapsulated during the fiber drawing process. Nanoparticles released from the fibers over time retained their bioactivity and successfully transfected cells seeded on the scaffold in a sustained manner. Transgene expression in HEK293 cells and human dermal fibroblasts seeded on the transfecting scaffolds was significant even after 2 weeks of culture compared to 3-day expression in two-dimensional controls. Fibroblasts seeded on scaffolds containing DNA encoding basic fibroblast growth factor (bFGF) demonstrated prolonged secretion of bFGF at levels significantly higher than baseline. This work establishes the potential of this fibrous scaffold as a matrix capable of delivering genes to direct and support cellular development in tissue engineering. PMID:16497560

Lim, Shawn H; Liao, I-Chien; Leong, Kam W

2006-02-23

337

The performance of laminin-containing cryogel scaffolds in neural tissue regeneration  

Microsoft Academic Search

Currently, there are no effective therapies to restore lost brain neurons, although rapid progress in stem cell biology and biomaterials development provides new tools for regeneration of central nervous system. Here we describe neurogenic properties of bioactive scaffolds generated by cryogelation of dextran or gelatin linked to laminin – the main component of brain extracellular matrix. We showed that such

Marcin Jurga; Maria B. Dainiak; Anna Sarnowska; Anna Jablonska; Anuj Tripathi; Fatima M. Plieva; Irina N. Savina; Lukasz Strojek; Hans Jungvid; Ashok Kumar; Barbara Lukomska; Krystyna Domanska-Janik; Nico Forraz; Colin P. McGuckin

2011-01-01

338

Ceramic composites as matrices and scaffolds for drug delivery in tissue engineering.  

PubMed

Ceramic composites and scaffolds are popular implant materials in the field of dentistry, orthopedics and plastic surgery. For bone tissue engineering especially CaP-ceramics or cements and bioactive glass are suitable implant materials due to their osteoconductive properties. In this review the applicability of these ceramics but also of ceramic/polymer composites for bone tissue engineering is discussed, and in particular their use as drug delivery systems. Overall, the high density and slow biodegradability of ceramics is not beneficial for tissue engineering purposes. To address these issues, macroporosity can be introduced often in combination with osteoinductive growth factors and cells. Ceramics are good carriers for drugs, in which release patterns are strongly dependent on the chemical consistency of the ceramic, type of drug and drug loading. Biodegradable polymers like polylactic acid, gelatin or chitosan are used as matrices for ceramic particles or as adjuvant to calcium phosphate cements. The use of these polymers can introduce a tailored biodegradation/drug release to the ceramic material. PMID:17478007

Habraken, W J E M; Wolke, J G C; Jansen, J A

2007-04-06

339

Exogenous phytoestrogenic molecule icaritin incorporated into a porous scaffold for enhancing bone defect repair.  

PubMed

This study was designed to develop a bioactive scaffold to enhance bone defect repair in steroid-associated osteonecrosis (SAON). Icaritin, a metabolite of the herb Epimedium, has been identified as an angiogenic and osteogenic phytomolecule. Icaritin was homogenized into poly lactic-co-glycolic acid/tricalcium phosphate (PLGA/TCP) to form an icaritin-releasing porous composite scaffold (PLGA/TCP/icaritin) by fine-spinning technology. In vitro, high performance liquid chromatography was used to determine the release of icaritin during degradation of PLGA/TCP/icaritin. The osteogenic effects of PLGA/TCP/icaritin were evaluated using rat bone marrow mesenchymal stem cells (BMSCs). In vivo, the osteogenic effect of PLGA/TCP/icaritin was determined within a bone tunnel after core decompression in SAON rabbits and angiography within scaffolds was examined in rabbit muscle pouch model. In vitro study confirmed the sustainable release of icaritin from PLGA/TCP/icaritin with the bioactive scaffold promoting the proliferation and osteoblastic differentiation of rat BMSCs. In vivo study showed that PLGA/TCP/icaritin significantly promoted new bone formation within the bone defect after core decompression in SAON rabbits and enhanced neovascularization in the rabbit muscle pouch experiment. In conclusion, PLGA/TCP/icaritin is an innovative local delivery system that demonstrates sustainable release of osteogenic phytomolecule icaritin enhancing bone repair in an SAON rabbit model. The supplement of scaffold materials with bioactive phytomolecule(s) might improve treatment efficiency in challenging orthopedic conditions. PMID:22807243

Wang, Xin-Luan; Xie, Xin-Hui; Zhang, Ge; Chen, Shi-Hui; Yao, Dong; He, Kai; Wang, Xiao-Hong; Yao, Xin-Sheng; Leng, Yang; Fung, Kwok-Pui; Leung, Kwok-Sui; Qin, Ling

2012-07-13

340

Bioactive coatings prepared by sol–gel on stainless steel 316L  

Microsoft Academic Search

This work describes the development and characterization of coatings obtained by the sol–gel technique, applied on stainless steel used in orthopaedic surgery. These coatings are applied to reduce metal corrosion and adverse reactions when implanted. Hybrid coatings of silica containing hydroxyapatite, bioactive glass and glass–ceramic particles were prepared and applied on metal substrates. The coated samples were further tested in

C. Garcia; S. Ceré; A. Durán

2004-01-01

341

Novel mesoporous silica-based antibiotic releasing scaffold for bone repair.  

PubMed

Tissue engineering scaffolds with a micro- or nanoporous structure and able to deliver special drugs have already been confirmed to be effective in bone repair. In this paper, we first evaluated the biomineralization properties and drug release properties of a novel mesoporous silica-hydroxyapatite composite material (HMS-HA) which was used as drug vehicle and filler for polymer matrices. Biomineralization can offer a credible prediction of bioactivity for the synthetic bone regeneration materials. We found HMS-HA exhibited good apatite deposition properties after being soaked in simulated body fluid (SBF) for 7 days. Drug delivery from HMS-HA particle was in line with Fick's law, and the release process lasted 12 h after an initial burst release with 60% drug release. A novel tissue engineering scaffold with the function of controlled drug delivery was developed, which was based on HMS-HA particles, poly(lactide-co-glycolide) (PLGA) and microspheres sintering techniques. Mechanical testing on compression, degradation behavior, pH-compensation effect and drug delivery behavior of PLGA/HMS-HA microspheres sintered scaffolds were analyzed. Cell toxicity and cell proliferation on the scaffolds was also evaluated. The results indicated that the PLGA/HMS-HA scaffolds could effectively compensate the increased pH values caused by the acidic degradation product of PLGA. The compressive strength and modulus of PLGA/HMS-HA scaffolds were remarkably high compared to pure PLGA scaffold. Drug delivery testing of the PLGA/HMS-HA scaffolds indicated that PLGA slowed gentamycin sulfate (GS) release from HMS-HA particles, and the release lasted for nearly one month. Adding HMS-HA to PLGA scaffolds improved cytocompatibility. The scaffolds demonstrated low cytotoxicity, and supported mesenchymal stem cells growth more effectively than pure PLGA scaffolds. To summarize, the data supports the development of PLGA/HMS-HA scaffolds as potential degradable and drug delivery materials for bone replacement. PMID:19217361

Shi, Xuetao; Wang, Yingjun; Ren, Li; Zhao, Naru; Gong, Yihong; Wang, Dong-An

2009-01-23

342

Effect of the substitution of La2O3 for CaO on the bioactivity of 2.5CaO.2SiO2 glass.  

PubMed

Glasses of the following composition were prepared: (2.5-x)CaO.x/3La2O3.2SiO2 (0 < or = x < or = 1). Their behavior when soaked in a simulated body fluid (SBF) was studied by means of electron microscopy (EM) equipped with an energy-dispersive system (EDS) for elemental analysis, IR spectroscopy, and x-ray diffraction. All the studied glasses react with SBF by forming a calcium phosphate layer. This layer appears to be increasingly thinner with increasing amounts of La2O3 substituted. The experimental results are in good agreement with mechanisms reported in the literature. Moreover they suggest that lanthanum oxide is retained in the layer below the phosphate. After 6 days of soaking, crystalline hydroxyapatite is formed in the case of La2O3 free glass. PMID:8884494

Fresa, R; Costantini, A; Buri, A; Branda, F

1996-10-01

343

Incorporation and controlled release of a hydrophilic antibiotic using poly(lactide-co-glycolide)-based electrospun nanofibrous scaffolds  

Microsoft Academic Search

The successful incorporation and sustained release of a hydrophilic antibiotic drug (Mefoxin®, cefoxitin sodium) from electrospun poly(lactide-co-glycolide) (PLGA)-based nanofibrous scaffolds without the loss of structure and bioactivity was demonstrated. The morphology and density of the electrospun scaffold was found to be dependent on the drug concentration, which could be attributed to the effect of ionic salt on the electrospinning process.

Kwangsok Kim; Yen K. Luu; Charles Chang; Dufei Fang; Benjamin S. Hsiao; Benjamin Chu; Michael Hadjiargyrou

2004-01-01

344

Effect of biomimetic 3D environment of an injectable polymeric scaffold on MG63 osteoblastic-cell response  

Microsoft Academic Search

Solid PLGA microspheres were fabricated and characterized in terms of their in vitro degradation behaviour. Microsphere scaffolds were then modified covalently by P-15 (GTPGPQGIAGQRGVV) to obtain a 3D bioactive collagen surrogate matrix for bone filling applications. These scaffolds were characterized for surface topography, hydrophilicity and evaluated for their effect on osteoblastic activity of MG-63 cell line vis-a-vis 2D monolayer culture.AFM

Shalini Verma; Neeraj Kumar

2010-01-01

345

PCL microspheres based functional scaffolds by bottom-up approach with predefined microstructural properties and release profiles  

Microsoft Academic Search

Advanced tissue engineering approaches rely upon the employment of biomaterials that integrate biodegradable scaffolds with growth factor delivery devices to better guide cellular activities and enhance tissue neogenesis. Along these lines, here we proposed a bottom-up approach for the realization of bioactive scaffolds with controllable pore size and interconnection, combined with protein-loaded polymeric microcarriers acting as local chrono-programmed point source

Alessia Luciani; Valentina Coccoli; Silvia Orsi; Luigi Ambrosio; Paolo A. Netti

2008-01-01

346

Electrostatic Control of Bioactivity  

SciTech Connect

The power of independence: When exhibited on the surface of self-assembling peptide-amphiphile nanofibers, the hydrophobic laminin-derived IKVAV epitope induced nanofiber bundling through interdigitation with neighboring fibers and thus decreased the bioactivity of the resulting materials. The inclusion of charged amino acids in the peptide amphiphiles disrupted the tendency to bundle and led to significantly enhanced neurite outgrowth.

Goldberger, Joshua E.; Berns, Eric J.; Bitton, Ronit; Newcomb, Christina J.; Stupp, Samuel I. (NWU)

2012-03-15

347

Scaffolds in Tendon Tissue Engineering  

PubMed Central

Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair.

Longo, Umile Giuseppe; Lamberti, Alfredo; Petrillo, Stefano; Maffulli, Nicola; Denaro, Vincenzo

2012-01-01

348

Fatigue and human umbilical cord stem cell seeding characteristics of calcium phosphate–chitosan–biodegradable fiber scaffolds  

Microsoft Academic Search

Calcium phosphate cement (CPC) has in situ-setting ability and bioactivity, but the brittleness and low strength limit CPC to only non-load-bearing bone repairs. Human umbilical cord mesenchymal stem cells (hUCMSCs) can be harvested without an invasive procedure required for the commonly studied bone marrow MSCs. However, little has been reported on hUCMSC delivery via bioactive scaffolds for bone tissue engineering.

Liang Zhao; Elena F. Burguera; Hockin H. K. Xu; Nikhil Amin; Heon Ryou; Dwayne D. Arola

2010-01-01

349

Osteochondral interface regeneration of the rabbit knee with macroscopic gradients of bioactive signals.  

PubMed

To date, most interfacial tissue engineering approaches have used stratified designs, in which there are two or more discrete layers comprising the interface. Continuously graded interfacial designs, where there is no discrete transition from one tissue type to another, are gaining attention as an alternative to stratified designs. Given that osteochondral regeneration holds the potential to enhance cartilage regeneration by leveraging the healing capacity of the underlying bone, we endeavored to introduce a continuously-graded approach to osteochondral regeneration. The purpose of this study was thus to evaluate the performance of a novel gradient-based scaffolding approach to regenerate osteochondral defects in the New Zealand White rabbit femoral condyle. Bioactive plugs were constructed from poly(D,L-lactic-co-glycolic acid) microspheres with a continuous gradient transition between cartilage-promoting and bone-promoting growth factors. At 6 and 12 weeks of healing, results suggested that the implants provided support for the neo-synthesized tissue, and the gradient in bioactive signaling may have been beneficial for bone and cartilage regeneration compared to the blank control implant, as evidenced by histology. In addition, the effects of preseeding gradient scaffolds with umbilical cord mesenchymal stromal cells (UCMSCs) from the Wharton's jelly of New Zealand White rabbits were evaluated. Results indicated that there may be regenerative benefits to prelocalizing UCMSCs within scaffold interiors. The inclusion of bioactive factors in a gradient-based scaffolding design is a promising new treatment strategy for defect repair in the femoral condyle. PMID:22009693

Dormer, Nathan H; Singh, Milind; Zhao, Liang; Mohan, Neethu; Berkland, Cory J; Detamore, Michael S

2011-10-19

350

Bioglass 45S5 transformation and molding material in the processing of biodegradable poly-DL-lactide scaffolds for bone tissue engineering  

NASA Astrophysics Data System (ADS)

When bone is damaged, a scaffold can temporarily replace it in the site of injury and incite bone tissue to repair itself. A biodegradable scaffold resorbs into the body, generating non-toxic degradation products as new tissue reforms; a bioactive scaffold encourages the surrounding tissue to regenerate. In the present study, we make composite biodegradable and bioactive scaffolds using poly-DL-lactide (PDLLA), a biodegradable polymer, and incorporate Bioglass 45S5 (BG) to stimulate scaffold bioactivity. BG has an interesting trait when immersed in body fluid, a layer of hydroxycarbonate apatite, similar to the inorganic component of bone, forms on its surface. It is of utmost importance to understand the fate of BG throughout the scaffold’s processing in order to assess the scaffold’s bioactivity. In this study, the established different stages of BG reactivity have been verified by monitoring pH during BG dissolution experiments and by conducting an elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES). The composite scaffolds are synthesized by the solvent casting and particulate leaching technique and their morphology assessed by scanning electron microscopy (SEM). To understand the transformations occurred in BG during scaffold synthesis, BG as received, as well BG treated in acetone and water (the fluids involved in scaffold processing) are characterized by Fourier transform infrared (FTIR), and x-ray photoelectron spectroscopy (XPS). The results are then compared with BG extracted from scaffolds after processing. BG has been determined to start reacting during the scaffold processing. In addition, its reactivity is influenced by BG particle size. The study suggests that the presence of the polymer provides a reactive environment for BG due to pH effects. Teflon molds in scaffold fabrication are inert and biocompatibile, but their stiffness presents a challenge during de-molding. Silicone-based and polyurethane molds are attractive because they are flexible. However, there is a possibility that silicone leaches either from the material itself or the agents used to enhance their performance onto the scaffold. The second study in this thesis focuses on different types of such flexible substrates (Sil940, polyurethane, polyether, polydimethylsiloxane). The presence of Si in PDLLA films prepared on each material is inspected using XPS. Films made on all four materials are found to contain Si, indicative of the dissolution of part of the substrate in the film. However, silicon in the Si-containing catalysts used in the synthesis of polyethers is not transferred to samples, when the polyether substrate is plasma coated.

Abdollahi, Sara

351

Gene delivery by surface immobilization of plasmid to tissue engineering scaffolds  

PubMed Central

Biomaterial scaffolds that serve as vehicles for gene delivery to promote expression of inductive factors have numerous regenerative medicine applications. In this report, we investigate plasmid delivery from biomaterial scaffolds using a surface immobilization strategy. Porous scaffolds were fabricated from poly(lactide-co-glycolide) (PLG), and plasmids were immobilized by drying. In vitro plasmid release indicated that the majority (>70%) of adsorbed plasmid was released within 24 hours and >98% within 3 days; however, in vivo implantation of the scaffolds at the subcutaneous site yielded transgene expression that persisted for at least 28 weeks and was localized to the site of implantation. Histological analysis of DNA-adsorbed scaffolds indicated that macrophages at the scaffold were transfected in the first two weeks following implantation, whereas muscle cells adjacent to the implant primarily expressed the transgene at 4 weeks. In addition to localized gene expression, a secreted protein (human factor IX) was retained at the implant site and not available systemically after 3 days, indicating minimal off-target effects. These findings demonstrate that surface immobilization of plasmid onto microporous PLG scaffolds can produce localized and long-term gene expression in vivo, which may be employed to enhance the bioactivity of scaffolds used for regenerative medicine.

Salvay, David M.; Zelivyanskaya, Marina; Shea, Lonnie D.

2010-01-01

352

Bioactive factors for tissue regeneration: state of the art  

PubMed Central

Summary There are three components for the creation of new tissues: cell sources, scaffolds, and bioactive factors. Unlike conventional medical strategies, regenerative medicine requires not only analytical approaches but also integrative ones. Basic research has identified a number of bioactive factors that are necessary, but not sufficient, for organogenesis. In skeletal development, these factors include bone morphogenetic proteins (BMPs), transforming growth factor ? TGF-?, Wnts, hedgehogs (Hh), fibroblast growth factors (FGFs), insulin-like growth factors (IGFs), SRY box-containing gene (Sox) 9, Sp7, and runt-related transcription factors (Runx). Clinical and preclinical studies have been extensively performed to apply the knowledge to bone and cartilage regeneration. Given the large number of findings obtained so far, it would be a good time for a multi-disciplinary, collaborative effort to optimize these known factors and develop appropriate drug delivery systems for delivering them.

Ohba, Shinsuke; Hojo, Hironori; Chung, Ung-il

2012-01-01

353

Effects of compatibility of deproteinized antler cancellous bone with various bioactive factors on their osteogenic potential.  

PubMed

Combinations of calcium phosphate scaffolds and bioactive factors are promising niche-mimetic solutions for repairing large-sized bone defects. However, the importance of compatibility between scaffolds and bioactive factors on their osteogenic outcomes has been largely ignored. This study aimed to investigate the compatibility of calcinated antler cancellous bone (CACB) scaffolds with various bioactive factors including icariin (ICA), velvet antler polypeptides (VAP) or recombinant human bone morphogenetic protein-2 (rhBMP-2) as well as their combinational osteogenic potential in vitro and in vivo. Scanning electron microscopy and fourier transform infrared spectroscopy confirmed the uniform distribution and chemical stability of the reagents on CABC. In vitro release profiles showed relative steady release of ICA from ICA/CACB, burst VAP release from VAP/CACB, and minimal rhBMP-2 release from rhBMP-2/CACB composites. When compared with VAP and rhBMP-2, incorporation of ICA within CACB resulted in most increased cell attachment, proliferation, alkaline phosphatase activity, osteogenic gene expression, and mineralization of rat bone marrow mesenchymal stem cells. In rabbit mandible critical-sized defects, the most extensive osteogenesis and neovascularization were observed in the ICA/CACB group. Differences between the VAP/CACB and rhBMP-2/CACB groups were not apparent. Interestingly, low pro-inflammatory (TNF-?, IL-6) and high anti-inflammatory (IL-10) mRNA levels were observed at scaffold implantation sites which were in close association with amount of new bone formation. These findings highlight that the compatibility between scaffolds and bioactive factors should been taken into account when considering the formula of optimized bone defect repair. PMID:24008040

Zhang, Xuehui; Xu, Mingming; Song, Lin; Wei, Yan; Lin, Yuanhua; Liu, Wentao; Heng, Boon C; Peng, Hui; Wang, Ying; Deng, Xuliang

2013-09-03

354

Multiscale photoacoustic microscopy of single-walled carbon nanotube-incorporated tissue engineering scaffolds.  

PubMed

Three-dimensional polymeric scaffolds provide structural support and function as substrates for cells and bioactive molecules necessary for tissue regeneration. Noninvasive real-time imaging of scaffolds and/or the process of tissue formation within the scaffold remains a challenge. Microcomputed tomography, the widely used technique to characterize polymeric scaffolds, shows poor contrast for scaffolds immersed in biological fluids, thereby limiting its utilities under physiological conditions. In this article, multiscale photoacoustic microscopy (PAM), consisting of both acoustic-resolution PAM (AR-PAM) and optical-resolution PAM (OR-PAM), was employed to image and characterize single-walled carbon-nanotube (SWNT)-incorporated poly(lactic-co-glycolic acid) polymer scaffolds immersed in biological buffer. SWNTs were incorporated to reinforce the mechanical properties of the scaffolds, and to enhance the photoacoustic signal from the scaffolds. By choosing excitation wavelengths of 570 and 638 nm, multiscale PAM could spectroscopically differentiate the photoacoustic signals generated from blood and from carbon-nanotube-incorporated scaffolds. OR-PAM, providing a fine lateral resolution of 2.6 ?m with an adequate tissue penetration of 660 ?m, successfully quantified the average porosity and pore size of the scaffolds to be 86.5%±1.2% and 153±15 ?m in diameter, respectively. AR-PAM further extended the tissue penetration to 2 mm at the expense of lateral resolution (45 ?m). Our results suggest that PAM is a promising tool for noninvasive real-time imaging and monitoring of tissue engineering scaffolds in vitro, and in vivo under physiological conditions. PMID:22082018

Cai, Xin; Paratala, Bhavna S; Hu, Song; Sitharaman, Balaji; Wang, Lihong V

2011-12-22

355

Development of Bioactive Peptide Amphiphiles for Therapeutic Cell Delivery  

PubMed Central

There is great clinical interest in cell-based therapies for ischemic tissue repair in cardiovascular disease. However, the regenerative potential of these therapies is limited due to poor cell viability and minimal retention following application. We report here the development of bioactive peptide amphiphile nanofibers displaying the fibronectin-derived RGDS cell adhesion epitope as a scaffold for therapeutic delivery of bone marrow derived stem and progenitor cells. When grown on flat substrates, a binary peptide amphiphile system consisting of 10% by weight RGDS-containing molecules and 90% negatively charged diluent molecules was found to promote optimal cell adhesion. This binary system enhanced adhesion 1.4 fold relative to substrates composed of only the non-bioactive diluent. Additionally, no enhancement was found upon scrambling the epitope and adhesion was no longer enhanced upon adding soluble RGDS to the cell media, indicating RGDS-specific adhesion. When encapsulated within self-assembled scaffolds of the binary RGDS nanofibers in vitro, cells were found to be viable and proliferative, increasing in number by 5.5 times after only 5 days, an effect again lost upon adding soluble RGDS. Cells encapsulated within a non-bioactive scaffold and those within a binary scaffold with scrambled epitope showed minimal viability and no proliferation. Cells encapsulated within this RGDS nanofiber gel also increase in endothelial character, evident by a decrease in the expression of CD34 paired with an increase in the expression of endothelial-specific markers VE-Cadherin, VEGFR2, and eNOS after 5 days. In an in vivo study, nanofibers and luciferase-expressing cells were co-injected subcutaneously in a mouse model. The binary RGDS material supported these cells in vivo, evident by a 3.2 fold increase in bioluminescent signal attributable to viable cells; this suggests the material has an anti-apoptotic and/or proliferative effect on the transplanted bone marrow cells. We conclude that the binary RGDS-presenting nanofibers developed here demonstrate enhanced viability, proliferation, and adhesion of associated bone marrow derived stem and progenitor cells. This study suggests potential for this material as a scaffold to overcome current limitations of stem cell therapies for ischemic diseases.

Webber, Matthew J.; Tongers, Jorn; Renault, Marie-Ange; Roncalli, Jerome G.; Losordo, Douglas W.

2009-01-01

356

Development of bioactive peptide amphiphiles for therapeutic cell delivery.  

PubMed

There is great clinical interest in cell-based therapies for ischemic tissue repair in cardiovascular disease. However, the regenerative potential of these therapies is limited due to poor cell viability and minimal retention following application. We report here the development of bioactive peptide amphiphile nanofibers displaying the fibronectin-derived RGDS cell adhesion epitope as a scaffold for therapeutic delivery of bone marrow derived stem and progenitor cells. When grown on flat substrates, a binary peptide amphiphile system consisting of 10 wt.% RGDS-containing molecules and 90wt.% negatively charged diluent molecules was found to promote optimal cell adhesion. This binary system enhanced adhesion 1.4-fold relative to substrates composed of only the non-bioactive diluent. Additionally, no enhancement was found upon scrambling the epitope and adhesion was no longer enhanced upon adding soluble RGDS to the cell media, indicating RGDS-specific adhesion. When encapsulated within self-assembled scaffolds of the binary RGDS nanofibers in vitro, cells were found to be viable and proliferative, increasing in number by 5.5 times after only 5 days, an effect again lost upon adding soluble RGDS. Cells encapsulated within a non-bioactive scaffold and those within a binary scaffold with scrambled epitope showed minimal viability and no proliferation. Cells encapsulated within this RGDS nanofiber gel also increase in endothelial character, evident by a decrease in the expression of CD34 paired with an increase in the expression of endothelial-specific markers VE-Cadherin, VEGFR2 and eNOS after 5 days. In an in vivo study, nanofibers and luciferase-expressing cells were co-injected subcutaneously in a mouse model. The binary RGDS material supported these cells in vivo, evident by a 3.2-fold increase in bioluminescent signal attributable to viable cells; this suggests the material has an anti-apoptotic and/or proliferative effect on the transplanted bone marrow cells. We conclude that the binary RGDS-presenting nanofibers developed here demonstrate enhanced viability, proliferation and adhesion of associated bone marrow derived stem and progenitor cells. This study suggests potential for this material as a scaffold to overcome current limitations of stem cell therapies for ischemic diseases. PMID:19635599

Webber, Matthew J; Tongers, Jörn; Renault, Marie-Ange; Roncalli, Jerome G; Losordo, Douglas W; Stupp, Samuel I

2009-07-25

357

Embedded silica nanoparticles in poly(caprolactone) nanofibrous scaffolds enhanced osteogenic potential for bone tissue engineering.  

PubMed

Poly(caprolactone) (PCL) has been frequently considered for bone tissue engineering because of its excellent biocompatibility. A drawback, however, of PCL is its inadequate mechanical strength for bone tissue engineering and its inadequate bioactivity to promote bone tissue regeneration from mesenchymal stem cells. To correct this deficiency, this work investigates the addition of nanoparticles of silica (nSiO(2)) to the scaffold to take advantage of the known bioactivity of silica as an osteogenic material and also to improve the mechanical properties through nanoscale reinforcement of the PCL fibers. The nanocomposite scaffolds and the pristine PCL scaffolds were evaluated physicochemically, mechanically, and biologically in the presence of human mesenchymal stem cells (hMSCs). The results indicated that, when the nanoparticles of size approximately 10 nm (concentrations of 0.5% and 1% w/v) were embedded within, or attached to, the PCL nanofibers, there was a substantial increase in scaffold strength, protein adsorption, and osteogenic differentiation of hMSCs. These nSiO(2) nanoparticles, when directly added to the cells evidently pointed to ingestion of these particles by the cells followed by cell death. The polymer nanofibers appeared to protect the cells by preventing ingestion of the silica nanoparticles, while at the same time adequately exposing them on fiber surfaces for their desired bioactivity. PMID:22725098

Ganesh, Nitya; Jayakumar, Rangasamy; Koyakutty, Manzoor; Mony, Ullas; Nair, Shantikumar V

2012-09-01

358

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

359

Wettable arrays onto superhydrophobic surfaces for bioactivity testing of inorganic nanoparticles  

Microsoft Academic Search

Poly(l-lactic acid) superhydrophobic surfaces prepared by a phase-separation methodology were treated with 30min exposition of UV\\/O3 irradiation using hollowed masks in order to obtain patterned superhydrophilic squared-shaped areas. These wettable areas successfully confined bioactive glass nanoparticles (BG-NPs), by dispensing and drying individual droplets of BG-NPs suspensions. The obtained biomimetic chips were used to test the in vitro bioactivity of binary

Gisela M. Luz; Álvaro J. Leite; Ana I. Neto; Wenlong Song; João F. Mano

2011-01-01

360

Scaffolds for tissue fabrication  

Microsoft Academic Search

Tissue engineering is an interdisciplinary and multidisciplinary field. It has shown great promise in generating living alternatives for harvested tissues and organs for transplantation and reconstructive surgery. Materials and fabrication technologies are critically important for tissue engineering in designing temporary, artificial extracellular matrices (scaffolds), which support three-dimensional tissue formation. This review briefly introduces the concept of tissue engineering, and illustrates

Peter X Ma

2004-01-01

361

Fibrin: a versatile scaffold for tissue engineering applications.  

PubMed

Tissue engineering combines cell and molecular biology with materials and mechanical engineering to replace damaged or diseased organs and tissues. Fibrin is a critical blood component responsible for hemostasis, which has been used extensively as a biopolymer scaffold in tissue engineering. In this review we summarize the latest developments in organ and tissue regeneration using fibrin as the scaffold material. Commercially available fibrinogen and thrombin are combined to form a fibrin hydrogel. The incorporation of bioactive peptides and growth factors via a heparin-binding delivery system improves the functionality of fibrin as a scaffold. New technologies such as inkjet printing and magnetically influenced self-assembly can alter the geometry of the fibrin structure into appropriate and predictable forms. Fibrin can be prepared from autologous plasma, and is available as glue or as engineered microbeads. Fibrin alone or in combination with other materials has been used as a biological scaffold for stem or primary cells to regenerate adipose tissue, bone, cardiac tissue, cartilage, liver, nervous tissue, ocular tissue, skin, tendons, and ligaments. Thus, fibrin is a versatile biopolymer, which shows a great potential in tissue regeneration and wound healing. PMID:18544016

Ahmed, Tamer A E; Dare, Emma V; Hincke, Max

2008-06-01

362

Impregnation of ?-tricalcium phosphate robocast scaffolds by in situ polymerization.  

PubMed

Ring-opening polymerization of ?-caprolactone (?-CL) and L-lactide (LLA) was performed to impregnate ?-tricalcium phosphate (?-TCP) scaffolds fabricated by robocasting. Concentrated colloidal inks prepared from ?-TCP commercial powders were used to fabricate porous structures consisting of a 3D mesh of interpenetrating rods. ?-CL and LLA were in situ polymerized within the ceramic structure by using a lipase and stannous octanoate, respectively, as catalysts. The results show that both the macropores inside the ceramic mesh and the micropores within the ceramic rods are full of polymer in either case. The mechanical properties of scaffolds impregnated by in situ polymerization (ISP) are significantly increased over those of the bare structures, exhibiting similar values than those obtained by other, more aggressive, impregnation methods such as melt-immersion (MI). ISP using enzymatic catalysts requires a reduced processing temperature which could facilitate the incorporation of growth factors and other drugs into the polymer composition, thus enhancing the bioactivity of the composite scaffold. The implications of these results for the optimization of the mechanical and biological performance of scaffolds for bone tissue engineering applications are discussed. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3086-3096, 2013. PMID:23526780

Martínez-Vázquez, Francisco J; Perera, Fidel H; Meulen, Inge van der; Heise, Andreas; Pajares, Antonia; Miranda, Pedro

2013-03-25

363

The in vivo behaviour of a sol–gel glass and a glass-ceramic during critical diaphyseal bone defects healing  

Microsoft Academic Search

The in vivo evaluation, in New Zealand rabbits, of a sol–gel glass 70% CaO–30% SiO2 (in mol%) and a glass-ceramic obtained from thermal treatment of the glass, both bioactive in Kokubo's simulated body fluid (SBF), is presented. Femoral bone diaphyseal critical defects were filled with: (i) sol–gel glass cylinders, (ii) glass-ceramic cylinders, or (iii) no material (control group). Osteosynthesis was

Jorge Gil-Albarova; Antonio J. Salinas; Antonio L. Bueno-Lozano; Jesus Román; Nicolo Aldini-Nicolo; Agustina García-Barea; Gianluca Giavaresi; Milena Fini; Roberto Giardino; Maria Vallet-Regí

2005-01-01

364

Monosaccharides as Scaffolds for the Synthesis of Novel Compounds  

NASA Astrophysics Data System (ADS)

This chapter focuses on monosaccharides and scaffolds their derivatives as scaffolds for the synthesis of primarily bioactive compounds. Such carbohydrate derivatives have been designed to modulate mainly protein-protein and peptide-protein interactions although modulators of carbohydrate-protein and carbohydrate-nucleic acid interactions have also been of interest. The multiple hydroxyl groups that are present on saccharides have made pyranose, furanose and iminosugars ideal templates or scaffolds to which recognition or pharmacophoric groups can be grafted to generate novel compounds for medicinal chemistry. The synthesis of compounds for evaluations require strategies for regioselective reactions of saccharide hydroxyl groups and use of orthogonally stable protecting groups. Syntheses have been carried out on the solid phase and in solution. Also the use of uronic acids, amino sugars and sugar amino acids has facilitated the synthesis of peptidomimetics and prospecting libraries as they enable, through presence of amino or carboxylic acid groups, chemoselective approaches to be employed in solution and on solid phase. Sugar amino acids are readily incorporated, as peptide isosteres, to generate sugar-peptide hybrids or for the synthesis of novel carbopeptoids . The synthesis of new cyclic compounds, derived in part from saccharides, and their application as scaffolds is an emerging area and recent examples include spirocyclic compounds, benzodiazepine-saccharide hybrids and macrolide-saccharide hybrids. Potent bioactive saccharide derivatives have been identified that include enzyme inhibitors , somatostatin receptor ligands, integrin ligands, anti-viral compounds, shiga toxin inhibitors and cell growth inhibitors. Some saccharide derivatives have demonstrated improved cellular permeability when compared with peptides and are in clinical trials.

Murphy, Paul V.; Velasco-Torrijos, Trinidad

365

Mechanical characterization of injection-molded macro porous bioceramic bone scaffolds.  

PubMed

Bioactive ceramic materials like tricalcium phosphate (TCP) have been emerging as viable material alternatives to the current therapies of bone scaffolding to target fracture healing and osteoporosis. Both material and architectural characteristics play a critical role in the osteoconductive capacity and strength of bone scaffolds. Thus, the objective of this research was to investigate the sintering temperature effect of a cost-effective manufacturing process on the architecture and mechanical properties of a controlled macro porous bioceramic bone scaffold. In this study the physical and mechanical properties of ?-TCP bioceramic scaffolds were investigated as a function of the sintering temperature in the range of 950-1150 °C. Physical properties investigated included bulk dimensions, pore size, and strut thickness; and, compressive mechanical properties were evaluated in air at room temperature and in saline solution at body temperature. Statistically significant increases in apparent elastic modulus were measured for scaffolds sintered at higher temperatures. Structural stiffness for all the specimens was significantly reduced when tested at body temperature in saline solution. These findings support the development of clinically successful bioceramic scaffolds that may stimulate bone regeneration and scaffold integration while providing structural integrity. PMID:22498292

Vivanco, Juan; Aiyangar, Ameet; Araneda, Aldo; Ploeg, Heidi-Lynn

2012-02-16

366

Surface Modification of High Porosity Alumina Scaffold by Silane Coupling Agent  

NASA Astrophysics Data System (ADS)

Alumina is a bioceramic with improved mechanical properties in comparison to hydroxyapatite. It is also an inert biomaterial in the human body environment of good biocompatible characteristics. Silane coupling agents are capable to form a durable bond between organic and inorganic materials. However, formation of hydroxyl functional groups may enhance coupling of silane molecules on the scaffolds surface and improves the bioactivity of inert alumina. In this research, alumina scaffolds were immersed in H2O2/H2SO4 solution. The hydrated scaffolds were then immersed in different concentrations of ?-Methacryloxy propyl trimethoxy silane (MTMS)/methanol/distilled water solutions. X-ray diffraction pattern was used for evaluation of phase changes. The structural changes were characterized by Fourier transform infrared spectroscopy. Morphology of the resulting scaffolds was observed by scanning electron microscopy and showed a thin layer of MTMS were formed on the alumina scaffold. The results confirmed the surface modification of alumina scaffolds were performed successfully by MTMS. These scaffolds had properly interconnected porosities with appropriate pore size that can be useful for hard tissues regeneration.

Joughehdoust, Sedigheh; Behnamghader, Aliasghar; Imani, Mohammad; Daliri, Morteza; Jabbari, Esmaeil

2011-12-01

367

Fabrication of porous polyvinyl alcohol scaffold for bone tissue engineering via selective laser sintering.  

PubMed

A tetragonal polyvinyl alcohol (PVA) scaffold with 3D orthogonal periodic porous architecture was fabricated via selective laser sintering (SLS) technology. The scaffold was fabricated under the laser power of 8 W, scan speed of 600 mm min(-1), laser spot diameter of 0.8 mm and layer thickness of 0.15 mm. The microstructure analysis showed that the degree of crystallization decreased while the PVA powder melts gradually and fuses together completely with laser power increasing. Thermal decomposition would occur if the laser power was further higher (16 W or higher in the case). The porous architecture was controllable and totally interconnected. The porosity of the fabricated scaffolds was measured to be 67.9 ± 2.7% which satisfies the requirement of micro-pores of the bone scaffolds. Its bioactivity and biocompatibility were also evaluated in vitro as tissue engineering (TE) scaffolds. In vitro adhesion assay showed that the amount of pores increased while the scaffold remains stable and intact after immersion in simulated body fluid for seven days. Moreover, the number of MG-63 cells and the bridge between cells increased with increasing time in cell culture. The present work demonstrates that PVA scaffolds with well-defined porous architectures via SLS technology were designed and fabricated for bone TE. PMID:23385303

Shuai, Cijun; Mao, Zhongzheng; Lu, Haibo; Nie, Yi; Hu, Huanlong; Peng, Shuping

2013-02-06

368

The performance of laminin-containing cryogel scaffolds in neural tissue regeneration.  

PubMed

Currently, there are no effective therapies to restore lost brain neurons, although rapid progress in stem cell biology and biomaterials development provides new tools for regeneration of central nervous system. Here we describe neurogenic properties of bioactive scaffolds generated by cryogelation of dextran or gelatin linked to laminin - the main component of brain extracellular matrix. We showed that such scaffolds promoted differentiation of human cord blood-derived stem cells into artificial neural tissue in vitro. Our experiments revealed that optimal range of scaffolds' pore size for neural tissue engineering was 80-100 microns. We found that scaffold seeded with undifferentiated, but not neutrally committed stem cells, gave optimal cell adhesion and proliferation in "niche"-like structures. Subsequent differentiation resulted in generation of mature 3D networks of neurons (MAP2+) and glia (S100beta+) cells. We showed that cryogel scaffolds could be transplanted into the brain tissue or organotypic hippocampal slices in a rat models. The scaffolds did not induced inflammation mediated by microglial cells (ED1-, Ox43-, Iba1-) and prevented formation of glial scar (GFAP-). Contrary, laminin-rich scaffolds attracted infiltration of host's neuroblasts (NF200+, Nestin+) indicating high neuroregeneration properties. PMID:21324403

Jurga, Marcin; Dainiak, Maria B; Sarnowska, Anna; Jablonska, Anna; Tripathi, Anuj; Plieva, Fatima M; Savina, Irina N; Strojek, Lukasz; Jungvid, Hans; Kumar, Ashok; Lukomska, Barbara; Domanska-Janik, Krystyna; Forraz, Nico; McGuckin, Colin P

2011-02-13

369

Broad spectrum bioactive sunscreens.  

PubMed

The development of sunscreens containing reduced concentration of chemical UV filters, even though, possessing broad spectrum effectiveness with the use of natural raw materials that improve and infer UV absorption is of great interest. Due to the structural similarities between polyphenolic compounds and organic UV filters, they might exert photoprotection activity. The objective of the present research work was to develop bioactive sunscreen delivery systems containing rutin, Passiflora incarnata L. and Plantago lanceolata extracts associated or not with organic and inorganic UV filters. UV transmission of the sunscreen delivery system films was performed by using diffuse transmittance measurements coupling to an integrating sphere. In vitro photoprotection efficacy was evaluated according to the following parameters: estimated sun protection factor (SPF); Boot's Star Rating category; UVA/UVB ratio; and critical wavelength (lambda(c)). Sunscreen delivery systems obtained SPF values ranging from 0.972+/-0.004 to 28.064+/-2.429 and bioactive compounds interacted with the UV filters positive and negatively. This behavior may be attributed to: the composition of the delivery system; the presence of inorganic UV filter and quantitative composition of the organic UV filters; and the phytochemical composition of the P. incarnata L. and P. lanceolata extracts. Among all associations of bioactive compounds and UV filters, we found that the broad spectrum sunscreen was accomplished when 1.68% (w/w) P. incarnata L. dry extract was in the presence of 7.0% (w/w) ethylhexyl methoxycinnamate, 2.0% (w/w) benzophenone-3 and 2.0% (w/w) TiO(2). It was demonstrated that this association generated estimated SPF of 20.072+/-0.906 and it has improved the protective defense against UVA radiation accompanying augmentation of the UVA/UVB ratio from 0.49 to 0.52 and lambda(c) from 364 to 368.6nm. PMID:18662760

Velasco, Maria Valéria Robles; Sarruf, Fernanda Daud; Salgado-Santos, Idalina Maria Nunes; Haroutiounian-Filho, Carlos Alberto; Kaneko, Telma Mary; Baby, André Rolim

2008-07-09

370

Bioactivity of polycrystalline silicon layers.  

PubMed

After oxygen, silicon is the second most abundant element in the environment and is present as an impurity in most materials. The widespread occurrence of siliceous biominerals as structural elements in lower plants and animals suggests that Si plays a role in the production and maintenance of connective tissue in higher organisms. It has been shown that the presence of Si is necessary in bones, cartilage and in the formation of connective tissue, as well as in some important metabolic processes. In this work, polycrystalline silicon layers are tested in terms of bioactivity, i.e., their ability to induce hydroxyapatite formation from simulated body fluid. Hydroxyapatite is a biologically compatible material with chemical similarity to the inorganic part of bones and teeth. Polycrystalline silicon layers are obtained by aluminum induced crystallization of Al and amorphous Si thin films deposited sequentially on glass substrates by radio-frequency magnetron sputtering and subsequently annealed in different atmospheres. The hydroxyapatite formation is induced by applying a method of laser-liquid-solid interaction. The method consists of irradiating the samples with laser light while immersed in a solution that is supersaturated with respect to Ca and P. As a result, heterogeneous porous sponge-like carbonate-containing hydroxyapatite is grown on the polysilicon surfaces. Crystals that are spherical in shape, containing Ca, P and O, Na, Cl, Mg, Al, Si and S, as well as well-faceted NaCl crystals are embedded in the hydroxyapatite layer. Enhancement of the hydroxyapatite growth and increased crystallinity is observed due to the applied laser-liquid-solid interaction. PMID:18464428

Pramatarova, Lilyana; Pecheva, Emilia; Montgomery, Paul; Dimova-Malinovska, Doriana; Petrov, Todor; Toth, Attila L; Dimitrova, Magdalena

2008-02-01

371

Biocompatibility and osteogenetic characteristics of new biocompatible glasses.  

PubMed

A fibre-shaped glass with qualities of biocompatibility and biodegradation could be promising for reconstructive bone surgery in orthopaedics and neurosurgery. New highly biocompatible glasses, originally made by the Italian Group of Study on Biocompatible Glass, are obtained both in cylinder and fibre shapes due to their original chemical composition (Glassfiber). This is the only glass which is also available as a continuous filament. Hydrolytic in vitro and in vivo tests demonstrate that these glasses present both good biocompatibility and adjustable biodegradation in relation to their chemical composition. The advantages of bioactive glass also being available as a continuous filament are suggested. PMID:1772954

Barbon, F; Locardi, B; Verità, M; Gabbi, C; Grispigni, C; Tranquilli Leali, P; Brach del Prever, E; Gallinaro, P; Cerulli, G; Del Bue, G L

1991-08-01

372

Interfacial reactions of glasses for biomedical application by scanning transmission electron microscopy and microanalysis.  

PubMed

Short-term physico-chemical reactions at the interface between bioactive glass particles and biological fluids are studied for three glasses with different bioactive properties; these glasses are in the SiO(2)-Na(2)O-CaO-P(2)O(5)-K(2)O-Al(2)O(3)-MgO system. Our aim is to show the difference between the mechanisms of their surface reactions. The relation between the composition and the bioactive properties of these glasses is also discussed. The elemental analysis is performed at the submicrometer scale by scanning transmission electron microscopy associated with energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy. After different immersion times (ranging from 0 to 96 h) of bioactive glass particles in a simulated biological solution, results show the formation of different surface layers at the glass periphery in the case of two bioactive glasses (A9 and BVA). For the third glass (BVH) we do not observe any surface layer formation or any modification of the glass composition. For the two other glasses (A9 and BVA), we observe the presence of different layers: an already observed (Si, O, Al) rich layer at the periphery, a previously demonstrated thin (Si, O) layer formed on top of the (Si, O, Al) layer and a (Ca, P) layer. We determine the different steps of the mechanisms of the surface reactions, which appear to be similar in these glasses, and compare the physico-chemical reactions and kinetics using the different immersion times. The A9 glass permits the observation of all important steps of the surface reactions which lead to bioactivity. This study shows the important relationship between composition and bioactivity which can determine the medical applicability of the glass. PMID:16701894

Banchet, V; Michel, J; Jallot, E; Wortham, L; Bouthors, S; Laurent-Maquin, D; Balossier, G

2006-03-24

373