The preferable mechanical properties of Mg alloys along with excellent compatibility with human bone have established their applicability as implant biomaterials.However,a higher corrosion/degradation rate of Mg alloy...The preferable mechanical properties of Mg alloys along with excellent compatibility with human bone have established their applicability as implant biomaterials.However,a higher corrosion/degradation rate of Mg alloys in body fluids limits its biomedical applications.In this direction,surface modification and coating are explored as appropriate strategies to mode the degradation rate of Mg alloys.The constituents of bioactive glass(BG)provide strength,bio-inertness and bone bonding capability.Hence,researchers have explored the coating of BG on Mg alloys and investigated chemical,mechanical and biological properties of the coated alloys.In this review,we have made an attempt to compile the literature works done on the coating of BG on Mg alloys and its features.Underlying interfacial aspects of the coated substrates towards the degradation behavior are highlighted.The way forward to further improve the coating characteristics of BG coated Mg alloys are remarked.展开更多
Bioactive glasses have been developed for medical applications in the body for bone and tissue repair and regeneration. We have developed a borate-containing bioactive glass (13-93B3, referred to as B3), which is unde...Bioactive glasses have been developed for medical applications in the body for bone and tissue repair and regeneration. We have developed a borate-containing bioactive glass (13-93B3, referred to as B3), which is undergoing clinical trials to assess its wound-healing properties. To complement the healing properties of B3, metal ion dopants have been added to enhance its antimicrobial properties. Bioactive glasses doped with silver, gallium or iodine ions were found to have broad spectrum antimicrobial effects on clinically relevant bacteria including MRSA. While the B3 glass alone was sufficient to produce antibacterial effects on select bacteria, adding dopants enhanced the broad-spectrum antibacterial properties: Live-Dead staining fluorescence microscopy suggests cell membrane integrity is disrupted in gram positive bacteria exposed to the glass compounds, but not gram negative bacteria, indicating multiple mechanisms of action for each glass formulation.展开更多
Natural biopolymers have excellent biocompatibility and biodegradability;they can be used as biomedical materials for wound healing.In this work,the Silk Fibroin(SF)andκ-carrageenan(κ-Car)composite films containing ...Natural biopolymers have excellent biocompatibility and biodegradability;they can be used as biomedical materials for wound healing.In this work,the Silk Fibroin(SF)andκ-carrageenan(κ-Car)composite films containing Zinc-doped Bioactive Glass(ZBG)have been fabricated for wound closure applications.The as-fabricated SF-κ-Car/ZBG composite films have excellent stretchability and foldability,which facilitates them for application as wound dressing.They also exhibit excellent hydrophilicity and water-absorption capacity,which can effectively absorb wound exudate and keep the wound sites under moist state.In addition,the composite films have a good antibacterial effect against S.aureus and E.coli in vitro,which can reduce the risk of wound infection.Their excellent cell compatibility is confirmed by the CCK-8 assay.The strong vascular proliferation and wound regeneration are found in SF-κ-Car/ZBG composite films on a mouse skin wound model.The SF-κCar/ZBG composite films can inhibit the secretion of inflammatory factors,and stimulate the production of vascular factors and collagen fibers.The results derived from the performed investigations revealed that the SF-κ-Car/ZBG composite films are a promising candidate dressing for wound healing applications.展开更多
Bioactive and bioresorbable composite was fabricated by a solvent evaporation technique using poly-L-lactide(PLLA) and bioactive glass (average particle size: 6.8 μm). Bioactive glass granules are homogeneously distr...Bioactive and bioresorbable composite was fabricated by a solvent evaporation technique using poly-L-lactide(PLLA) and bioactive glass (average particle size: 6.8 μm). Bioactive glass granules are homogeneously distributed in the composite with microcrack structure. The formation of hydroxyapatite(HA) on the composite in simulated body fluid(SBF) was analyzed by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), X-ray diffraction(XRD), and Raman spectra. Rod-like HA crystals deposit on the surface of PLLA/bioactive glass composite after soaking for 3 d. Both rod-like crystals and HA layer form on the surface for 14 d in SBF. The high bioactivity of PLLA/bioactive glass composite indicates the potential of materials for integration with bone.展开更多
The key research and development steps for bioactive glass (45S5 Bioglass) are documented from the date of discovery in 1969 through FDA approvals of the first dental, ENT, maxillo-facial and orthopedic clinical produ...The key research and development steps for bioactive glass (45S5 Bioglass) are documented from the date of discovery in 1969 through FDA approvals of the first dental, ENT, maxillo-facial and orthopedic clinical products. Understanding the mechanisms and quantifying the rapid surface reactions to form a bone-bonding hydroxyl-carbonate apatite (HCA) layer on the bioactive glass in contact with living bone was a vital part of the early development of this class of biomaterials. A key later discovery was enhanced osteogenesis and in situ bone regeneration by controlled release of ionic dissolution products from the bioactive glass particulates that leads to up-regulation and activation of seven families of genes, a process called osteostimulation.展开更多
The system of SiO2-CaO-P2O5 bioactive glasses(BG) were successfully synthesized by microemulsion approach.X-ray diffraction(XRD),scanning electron micro scopy(SEM) and energy dispersive X-ray(EDX) analyses,transmissio...The system of SiO2-CaO-P2O5 bioactive glasses(BG) were successfully synthesized by microemulsion approach.X-ray diffraction(XRD),scanning electron micro scopy(SEM) and energy dispersive X-ray(EDX) analyses,transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FTIR),BET N2 gas adsorption analysis techniques were utilized in order to evaluate the phase composition,dimension,morphology,interconnectivity of pores and particle size of the synthesized BG respectiveely.The biocompatibility of BG was assessed by using dimethylthiazol diphenyl tetrazolium bromide(MTT).The BG scaffolds were implanted in rabbit mandibles and studied histologically.The results showed that the BG with a particle size less than 100 nm was prepared successfully.The measured BET specific surface area and pore volume was 113.9 m2/g and 0.28 cm3/g respectively.Cell cultures revealed that BG has been shown to have good biocompatibility and is also beneficial to the survival of Schwann cells,which can promote cell proliferation in vivo assay indicating that the BG can promote osteoconductivity.展开更多
Bioactive glass is well known for its ability of bone regeneration,and sol-gel hioactive glass has many advantages com- pared with melt-derived bioactive glass.3-D scaffold prepared by the sol-gel method is a promisin...Bioactive glass is well known for its ability of bone regeneration,and sol-gel hioactive glass has many advantages com- pared with melt-derived bioactive glass.3-D scaffold prepared by the sol-gel method is a promising substrate material for bone tissue engineering and large-scale bone repair.Porous sol-gel glass in the CaO-SiO_2-P_2O_5 system with macropores larger than 100μm was prepared by the addition of stearic acid as a pore former.The diameter of the pore created by the pore former varied from 100 to 300μm.The formation of a hydroxyapatite layer on the glass was analyzed by studying the surface of the porous glass by scanning elec- tron microscopy,energy dispersive spectroscopy,X-ray diffraction,and Raman spectra after they had been immersed in simulated body fluid(SBF)for some time,and the porous glass shows good bioactivity.展开更多
Biointerface design that targets osteogenesis is a growing area of research with significant implications in biomedicine. Materials known to either support or stimulate osteogenesis are composed of a biomimetic cerami...Biointerface design that targets osteogenesis is a growing area of research with significant implications in biomedicine. Materials known to either support or stimulate osteogenesis are composed of a biomimetic ceramic material, such as bioactive glass. Bioactive glass is osteoproductive, and the potential for osteoproductivity can be enhanced by the addition of proteins or other additives designed to alter functionality. In addition, soluble growth factors are often added to osteogenic culture on bioactive glasses, further intensifying the effects of the material. In this paper, synthetic peptide combinations, covalently bound to a three-dimensional bioactive glass network, are used to mimic the effects of the whole fibronectin and bone morphogenetic proteins (BMP) 2 and 9. Peptide-silanes possessing critical binding sequences from each of these proteins are synthesized and used to decorate the surface of three-dimensional (3D) nano-macroporous bioactive glass. MC3T3 preosteoblast cells are then assessed for differentiation on the materials in the absence of soluble differentiation cues. MC3T3 preosteoblasts undergo enhanced differentiation on the peptide-silane samples over the standard nano-macroporous bioactive glass, and the differentiation capacity of the cells exposes only to peptide-silane surfaces approaches that of cells grown in chemical differentiation induction media.展开更多
The effect of glass ionomer cement and resin-modified glass ionomer cement incorporated with chlorhexidine and bioactive glass on antimicrobial activity and physicochemical properties were investigated.The experimenta...The effect of glass ionomer cement and resin-modified glass ionomer cement incorporated with chlorhexidine and bioactive glass on antimicrobial activity and physicochemical properties were investigated.The experimental results showed that groups incorporated with 1% chlorhexidine exhibited a significant reduction of optical density values of the bacterial suspension and increased the degradation of Streptococcus mutans biofilm.However,groups incorporated with 10% bioactive glass did not affect the optical density values and the biofilm formation.The mechanical properties of the materials and the polymerization were not influenced by the addition of chlorhexidine.Nevertheless,the compressive strength was lower when the materials were incorporated with bioactive glass.It can be concluded that glass ionomer cements incorporated with chlorhexidine can maintain its mechanical properties as well as reduce early S mutans biofilm formation.Controlled release/sustained release technology may be required to optimize the antibacterial activity of glass ionomer cements incorporated with bioactive glass.展开更多
A new type of machinable bioactive glass-ceramicsfor bone substitution has been developed in the glasssystem SiO<sub>2</sub>-MgO-K<sub>2</sub>O-F<sup>-</sup>-CaO-P<sub>2</s...A new type of machinable bioactive glass-ceramicsfor bone substitution has been developed in the glasssystem SiO<sub>2</sub>-MgO-K<sub>2</sub>O-F<sup>-</sup>-CaO-P<sub>2</sub>O<sub>5</sub>, which contains Mg-muscovite [K<sub>2</sub>Mg<sub>5</sub> (Si<sub>8</sub>O<sub>20</sub>) F<sub>4</sub>] and fluorapatite as thetwo main crystal phases. The phase separation andthe crystallization of the glass have been studied.A series of tests have showed that the material isgood at mechanical property and bioactivity. Espe-cially, by analysing the structure of the interfacelayer between the material and the bone of animalwith scanning electron microscope, electron probe,etc., it has been found that the new bone hydroxya-patite is formed on the surface of the material sothat the material is connected firmly with the bone.展开更多
Based on a series of newly developed bioactive glasses having suitable thermo-mechanical properties to allow application as fixation agents between bone and titanium alloy biomedical implants, the stress corrosion cra...Based on a series of newly developed bioactive glasses having suitable thermo-mechanical properties to allow application as fixation agents between bone and titanium alloy biomedical implants, the stress corrosion crack growth(SCCG) behavior of their interfaces with Ti6Al4V was investigated in simulated body fluid (SBF) with the objectiveof discerning the salient mechanisms of crack advance and to assess the reliability of the bonds. Results indicatedthat crack growth rates in Ti6Al4V/glass/Ti6Al4V sandwich specimens were nearly the same as or slightly lowerthan those in the bulk glasses at comparable stress intensities; indeed, cracks would prefer to propagate off theinterface, suggesting that the Ti6Al4V/glass interface has relatively good crack-growth resistance. Mechanistically,interfacial crack growth appears to be controlled by the classic stress corrosion mechanisms for silicate glasses, withno discernible effect of bioactivity on the SCCG behavior being observed.展开更多
In order to accelerate the chronic wounds healing, we investigated the healing effects of bioactive glass and Yunnan baiyao ointments in streptozotocin-induced diabetic rats. The ointments were prepared by mixing 45S5...In order to accelerate the chronic wounds healing, we investigated the healing effects of bioactive glass and Yunnan baiyao ointments in streptozotocin-induced diabetic rats. The ointments were prepared by mixing 45S5 bioactive glass powder(16% weight) with Vaseline and different weight percentages of Yunnan baiyao. Full-thickness defect wounds were created on the back of 130 SD rats and were randomly divided into 8 groups. The wound healing rates were calculated at 4, 7, 10, 14 and 21 days after surgery. The samples were harvested for further observations. Considering the wound closure rate, group 6(with 5% Yunnan baiyao) has better wound healing performance than other diabetic groups. The lower infl ammatory response was observed by gross observation and confirmed by the results of H&E staining and TEM observation. Besides, the proliferation of fibroblasts, the formation of granulation tissue, as well as the vascularization, were improved in group 6 compared to other diabetic groups. All results suggest that bioactive glass and Yunnan baiyao ointments can accelerate the recovery of diabetes-impaired skin wounds, and comparing to other diabetic groups, group 6(with 5% Yunnan baiyao) has better healing effect.展开更多
The purpose of this research was to prepare machinable bioactive glass-ceramics by sol-gel method. A multi-component composite sol with great uniformity and stability was first prepared by a 2-step method. The composi...The purpose of this research was to prepare machinable bioactive glass-ceramics by sol-gel method. A multi-component composite sol with great uniformity and stability was first prepared by a 2-step method. The composite sol was then transformed into gel by aging under different temperatures. The gel was dried finally by super critically drying method and sintered to obtain the machinable bioactive glass-ceramics. Effect of thermal treatment on crystallization of the glass-ceramics was investigated by X-ray diffraction (XRD) analysis. Microstructure of the glass-ceramics was observed by Scanning Electron Microscopy (SEM) and the mechanism of machinability was discussed. Phlogopite and hydroxylapatite were identified as main crystal phases by XRD analysis under thermal treatment at 750 ℃ and 950 ℃ for 1.5 h separately. The relative bulk density could achieve 99% under 1050 ℃ for 4 h. Microstructure of the glass-ceramics showed that the randomly distributed phlogopite and hydroxylapatite phases were favorable to the machinability of the glass-ceramics. A mean bending strength of about 160-180 MPa and a fracture toughness parameter K_ IC of about 2.1-2.3 were determined for the glass-ceramics.展开更多
Bioactive and bioresorbable composite materials were fabricated from poly-L-lactide and bioactive glass (average particle size 6.8 μm) by a solvent evaporation technique.Cellular cultivation in vitro and MTT assay we...Bioactive and bioresorbable composite materials were fabricated from poly-L-lactide and bioactive glass (average particle size 6.8 μm) by a solvent evaporation technique.Cellular cultivation in vitro and MTT assay were conducted for evaluating the influence on morphology,growth and proliferation of cultured fibroblasts.The results of cytotoxicity testing show that cells cultured in extracts of PLLA/BG and on the surface of composites demonstrate normal growth and proliferation.The bioactive glass in PLLA composite facilitates both adhesion and proliferation of rat fibroblasts on PLLA/bioactive glass composite film.展开更多
Coating the hydroxyapatite (HA) on the titanium alloy surface can obtain a bioactive implant with high mechanical properties.However,the bonding force between the titanium alloy and the HA was low due to their differe...Coating the hydroxyapatite (HA) on the titanium alloy surface can obtain a bioactive implant with high mechanical properties.However,the bonding force between the titanium alloy and the HA was low due to their different coefficient of thermal expansion (CET).Preparing the multi-layer coating with alleviated thermal stress on titanium alloy substrate is few reported.Fabrication of a TiO2-bioactive glass (BG)-HA bioactive coating was proposed to solve this problem.A particular TiO2 surface was prepared on the titanium alloy substrate by micro-arc oxidation treatment.The BG and HA coating were coated onto the TiO2 surface in turn by using a sol-gel method.The microstructure,surface morphology and phase composition of the coatings were analyzed.The bonding force of coatings was investigated by the nick apparatus.In vitro dissolution was performed by soaking the TiO2-BG-HA coated samples into the simulated body fluid for various periods.Micro-structural observations indicated that no delamination and crack occurred at the interface of HA/BG and BG/TiO2.The bonding between the substrate and coating consists of the mechanical interaction and the chemical bonding.The bonding force could reach about 45 N.The TiO2-BG-HA coating displayed the excellent forming ability of bone-like apatite when it was soaked into the simulated body fluid.This work suggests an innovative way to reduce the internal stress among coatings through varying BG composition to adjust its CTE,so as to enhance the bonding force.展开更多
The prevalence of cases of antibiotic resistant infections and the limited number of new antibiotics call for new strategies to prevent bacterial infections. In this study, we evaluate the effectiveness of three diffe...The prevalence of cases of antibiotic resistant infections and the limited number of new antibiotics call for new strategies to prevent bacterial infections. In this study, we evaluate the effectiveness of three different compositions of bioactive glass, doped with silver as an antimicrobial agent for potential applications in preventing bacterial infections. The different glasses were formulated to dissolve and release silver at different rates enabling their use in different applications either individually or in combination to achieve a desired effect. Silver oxide (Ag<sub>2</sub>O) was incorporated into various glass formulations and antibacterial effectiveness was measured using radius of inhibition. Each silver-doped glass effectively inhibited the growth of <i>Escherichia coli</i>, <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i> with radius of inhibition correlating directly with the dissolution rate of the glass—the faster dissolving glass producing the larger radius of inhibition. Suspending particles of the silver containing glass in phosphate buffered saline or fetal calf serum, slowed the dissolution of each glass and extended the effectiveness of the silver containing glass over time (based on size of the radius of inhibition) compared to water. Potential applications of the powdered glass formulations would be to incorporate glasses with different properties into coatings or cosmetics. To investigate the feasibility of these applications, the silver-glass powder was incorporated into polycaprolactone polymer to determine the antibacterial properties of the imbedded glass powder. Based on this investigation, the silver glass formulations reported herein have potential applications in the medical device, dental, pharmaceutical and cosmetic industries.展开更多
Bioactive glass ceramic with SiO2-Ca2O-Na2O-P2O5 composition was prepared by the sol-gel method using sodium metasilicate (Na2SiO3) as silica source. The monolith obtained was sintered at 1000?C for 2 hours after whic...Bioactive glass ceramic with SiO2-Ca2O-Na2O-P2O5 composition was prepared by the sol-gel method using sodium metasilicate (Na2SiO3) as silica source. The monolith obtained was sintered at 1000?C for 2 hours after which X-ray diffraction (XRD) analysis showed presence of combeite (Na2Ca2Si3O9) as the crystalline phase. In vitro bioactivity test conducted on the material using simulated body fluid (SBF) showed the formation of carbonated hydroxyapatite on its surface. The material during the SBF test was observed to transform from a mechanically strong crystalline phase Na2Ca2Si3O9 to an amorphous phase after incubation for 14 days indicating that the material was biodegradable. Scanning electron microscopy (SEM) was used to investigate the surface morphology, while Fourier transform infrared (FTIR) spectroscopy facilitated the confirmation of hydroxyapatite (HA) formation. The monolith material obtained may be a good candidate for application in tissue engineering scaffolds.展开更多
Porous sol-gel glass of CaO-SiO2-P2O5 system with macropores larger than 100 μm was prepared by adding stearic acid as pore former when the sintering was carried out at 700 ℃ for 3h.The sol-gel porous glass shows an...Porous sol-gel glass of CaO-SiO2-P2O5 system with macropores larger than 100 μm was prepared by adding stearic acid as pore former when the sintering was carried out at 700 ℃ for 3h.The sol-gel porous glass shows an amorphous structure. The diameter of the pore created by pore former varies from 100 to 300 μm, and macroporous glass has a narrow and small pore size distribution in mesoporous scale. The porosity and pore size of macroporous bioactive glass can be controlled.展开更多
Glass-ceramic samples, having composition of SiO<sub>2</sub>-35, CaO-45, Na<sub>2</sub>O-10 and P<sub>2</sub>O<sub>5</sub>-10 in weight ratio were prepared through sinte...Glass-ceramic samples, having composition of SiO<sub>2</sub>-35, CaO-45, Na<sub>2</sub>O-10 and P<sub>2</sub>O<sub>5</sub>-10 in weight ratio were prepared through sintering route. Glass powder was reinforced by Al powder. The strength of glass-ceramic composite was found to be temperature dependent, and it varies with the addition of Al powder. Flexural strength increases with the increase of powder addition and sintering temperature, however, decreases with the increase of sintering time. There is an optimum temperature (>1100℃) above which flexural strength of all samples decreases. Bulk density changes to a higher value as the addition of Al-powder increases up to 3% by weight above which density decreases slowly. On the other hand, apparent porosity and water absorption decrease with the increase of percentage of Al powder added. Porosity and water absorption also showed a dependent characteristic on sintering time and sintering temperature.展开更多
文摘The preferable mechanical properties of Mg alloys along with excellent compatibility with human bone have established their applicability as implant biomaterials.However,a higher corrosion/degradation rate of Mg alloys in body fluids limits its biomedical applications.In this direction,surface modification and coating are explored as appropriate strategies to mode the degradation rate of Mg alloys.The constituents of bioactive glass(BG)provide strength,bio-inertness and bone bonding capability.Hence,researchers have explored the coating of BG on Mg alloys and investigated chemical,mechanical and biological properties of the coated alloys.In this review,we have made an attempt to compile the literature works done on the coating of BG on Mg alloys and its features.Underlying interfacial aspects of the coated substrates towards the degradation behavior are highlighted.The way forward to further improve the coating characteristics of BG coated Mg alloys are remarked.
文摘Bioactive glasses have been developed for medical applications in the body for bone and tissue repair and regeneration. We have developed a borate-containing bioactive glass (13-93B3, referred to as B3), which is undergoing clinical trials to assess its wound-healing properties. To complement the healing properties of B3, metal ion dopants have been added to enhance its antimicrobial properties. Bioactive glasses doped with silver, gallium or iodine ions were found to have broad spectrum antimicrobial effects on clinically relevant bacteria including MRSA. While the B3 glass alone was sufficient to produce antibacterial effects on select bacteria, adding dopants enhanced the broad-spectrum antibacterial properties: Live-Dead staining fluorescence microscopy suggests cell membrane integrity is disrupted in gram positive bacteria exposed to the glass compounds, but not gram negative bacteria, indicating multiple mechanisms of action for each glass formulation.
基金supported by the Zhejiang Provincial Natural Science Foundation(LBY20H110001,LY18E030006)National Natural Science Foundation of China(51873194,51373155).
文摘Natural biopolymers have excellent biocompatibility and biodegradability;they can be used as biomedical materials for wound healing.In this work,the Silk Fibroin(SF)andκ-carrageenan(κ-Car)composite films containing Zinc-doped Bioactive Glass(ZBG)have been fabricated for wound closure applications.The as-fabricated SF-κ-Car/ZBG composite films have excellent stretchability and foldability,which facilitates them for application as wound dressing.They also exhibit excellent hydrophilicity and water-absorption capacity,which can effectively absorb wound exudate and keep the wound sites under moist state.In addition,the composite films have a good antibacterial effect against S.aureus and E.coli in vitro,which can reduce the risk of wound infection.Their excellent cell compatibility is confirmed by the CCK-8 assay.The strong vascular proliferation and wound regeneration are found in SF-κ-Car/ZBG composite films on a mouse skin wound model.The SF-κCar/ZBG composite films can inhibit the secretion of inflammatory factors,and stimulate the production of vascular factors and collagen fibers.The results derived from the performed investigations revealed that the SF-κ-Car/ZBG composite films are a promising candidate dressing for wound healing applications.
基金Project(50174059) supported by the National Natural Science Foundation of China
文摘Bioactive and bioresorbable composite was fabricated by a solvent evaporation technique using poly-L-lactide(PLLA) and bioactive glass (average particle size: 6.8 μm). Bioactive glass granules are homogeneously distributed in the composite with microcrack structure. The formation of hydroxyapatite(HA) on the composite in simulated body fluid(SBF) was analyzed by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), X-ray diffraction(XRD), and Raman spectra. Rod-like HA crystals deposit on the surface of PLLA/bioactive glass composite after soaking for 3 d. Both rod-like crystals and HA layer form on the surface for 14 d in SBF. The high bioactivity of PLLA/bioactive glass composite indicates the potential of materials for integration with bone.
文摘The key research and development steps for bioactive glass (45S5 Bioglass) are documented from the date of discovery in 1969 through FDA approvals of the first dental, ENT, maxillo-facial and orthopedic clinical products. Understanding the mechanisms and quantifying the rapid surface reactions to form a bone-bonding hydroxyl-carbonate apatite (HCA) layer on the bioactive glass in contact with living bone was a vital part of the early development of this class of biomaterials. A key later discovery was enhanced osteogenesis and in situ bone regeneration by controlled release of ionic dissolution products from the bioactive glass particulates that leads to up-regulation and activation of seven families of genes, a process called osteostimulation.
基金Funded by Guangdong Science and Technology Tackling Project(No.2010B031100002)the Orientation of Lu'an Commissioned the West Anhui University Municipal Research Project(No.2011LW009)
文摘The system of SiO2-CaO-P2O5 bioactive glasses(BG) were successfully synthesized by microemulsion approach.X-ray diffraction(XRD),scanning electron micro scopy(SEM) and energy dispersive X-ray(EDX) analyses,transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FTIR),BET N2 gas adsorption analysis techniques were utilized in order to evaluate the phase composition,dimension,morphology,interconnectivity of pores and particle size of the synthesized BG respectiveely.The biocompatibility of BG was assessed by using dimethylthiazol diphenyl tetrazolium bromide(MTT).The BG scaffolds were implanted in rabbit mandibles and studied histologically.The results showed that the BG with a particle size less than 100 nm was prepared successfully.The measured BET specific surface area and pore volume was 113.9 m2/g and 0.28 cm3/g respectively.Cell cultures revealed that BG has been shown to have good biocompatibility and is also beneficial to the survival of Schwann cells,which can promote cell proliferation in vivo assay indicating that the BG can promote osteoconductivity.
基金the National Natural Science Foundation of China(No.50174059)
文摘Bioactive glass is well known for its ability of bone regeneration,and sol-gel hioactive glass has many advantages com- pared with melt-derived bioactive glass.3-D scaffold prepared by the sol-gel method is a promising substrate material for bone tissue engineering and large-scale bone repair.Porous sol-gel glass in the CaO-SiO_2-P_2O_5 system with macropores larger than 100μm was prepared by the addition of stearic acid as a pore former.The diameter of the pore created by the pore former varied from 100 to 300μm.The formation of a hydroxyapatite layer on the glass was analyzed by studying the surface of the porous glass by scanning elec- tron microscopy,energy dispersive spectroscopy,X-ray diffraction,and Raman spectra after they had been immersed in simulated body fluid(SBF)for some time,and the porous glass shows good bioactivity.
文摘Biointerface design that targets osteogenesis is a growing area of research with significant implications in biomedicine. Materials known to either support or stimulate osteogenesis are composed of a biomimetic ceramic material, such as bioactive glass. Bioactive glass is osteoproductive, and the potential for osteoproductivity can be enhanced by the addition of proteins or other additives designed to alter functionality. In addition, soluble growth factors are often added to osteogenic culture on bioactive glasses, further intensifying the effects of the material. In this paper, synthetic peptide combinations, covalently bound to a three-dimensional bioactive glass network, are used to mimic the effects of the whole fibronectin and bone morphogenetic proteins (BMP) 2 and 9. Peptide-silanes possessing critical binding sequences from each of these proteins are synthesized and used to decorate the surface of three-dimensional (3D) nano-macroporous bioactive glass. MC3T3 preosteoblast cells are then assessed for differentiation on the materials in the absence of soluble differentiation cues. MC3T3 preosteoblasts undergo enhanced differentiation on the peptide-silane samples over the standard nano-macroporous bioactive glass, and the differentiation capacity of the cells exposes only to peptide-silane surfaces approaches that of cells grown in chemical differentiation induction media.
基金Funded by the National Natural Science Foundation of China (No.81070852)the Open Research Fund Program of Hubei-MOST KLOS & KLOBME (200903)the Science and Technology Project of Wuhan(201161038343-02)
文摘The effect of glass ionomer cement and resin-modified glass ionomer cement incorporated with chlorhexidine and bioactive glass on antimicrobial activity and physicochemical properties were investigated.The experimental results showed that groups incorporated with 1% chlorhexidine exhibited a significant reduction of optical density values of the bacterial suspension and increased the degradation of Streptococcus mutans biofilm.However,groups incorporated with 10% bioactive glass did not affect the optical density values and the biofilm formation.The mechanical properties of the materials and the polymerization were not influenced by the addition of chlorhexidine.Nevertheless,the compressive strength was lower when the materials were incorporated with bioactive glass.It can be concluded that glass ionomer cements incorporated with chlorhexidine can maintain its mechanical properties as well as reduce early S mutans biofilm formation.Controlled release/sustained release technology may be required to optimize the antibacterial activity of glass ionomer cements incorporated with bioactive glass.
文摘A new type of machinable bioactive glass-ceramicsfor bone substitution has been developed in the glasssystem SiO<sub>2</sub>-MgO-K<sub>2</sub>O-F<sup>-</sup>-CaO-P<sub>2</sub>O<sub>5</sub>, which contains Mg-muscovite [K<sub>2</sub>Mg<sub>5</sub> (Si<sub>8</sub>O<sub>20</sub>) F<sub>4</sub>] and fluorapatite as thetwo main crystal phases. The phase separation andthe crystallization of the glass have been studied.A series of tests have showed that the material isgood at mechanical property and bioactivity. Espe-cially, by analysing the structure of the interfacelayer between the material and the bone of animalwith scanning electron microscope, electron probe,etc., it has been found that the new bone hydroxya-patite is formed on the surface of the material sothat the material is connected firmly with the bone.
文摘Based on a series of newly developed bioactive glasses having suitable thermo-mechanical properties to allow application as fixation agents between bone and titanium alloy biomedical implants, the stress corrosion crack growth(SCCG) behavior of their interfaces with Ti6Al4V was investigated in simulated body fluid (SBF) with the objectiveof discerning the salient mechanisms of crack advance and to assess the reliability of the bonds. Results indicatedthat crack growth rates in Ti6Al4V/glass/Ti6Al4V sandwich specimens were nearly the same as or slightly lowerthan those in the bulk glasses at comparable stress intensities; indeed, cracks would prefer to propagate off theinterface, suggesting that the Ti6Al4V/glass interface has relatively good crack-growth resistance. Mechanistically,interfacial crack growth appears to be controlled by the classic stress corrosion mechanisms for silicate glasses, withno discernible effect of bioactivity on the SCCG behavior being observed.
基金Funded by the National Natural Science Foundation of China(Nos.50830101,51172073)the National Program on Key Basic Research Project(973 Program)(Nos.2011CB606204,2012CB619100)
文摘In order to accelerate the chronic wounds healing, we investigated the healing effects of bioactive glass and Yunnan baiyao ointments in streptozotocin-induced diabetic rats. The ointments were prepared by mixing 45S5 bioactive glass powder(16% weight) with Vaseline and different weight percentages of Yunnan baiyao. Full-thickness defect wounds were created on the back of 130 SD rats and were randomly divided into 8 groups. The wound healing rates were calculated at 4, 7, 10, 14 and 21 days after surgery. The samples were harvested for further observations. Considering the wound closure rate, group 6(with 5% Yunnan baiyao) has better wound healing performance than other diabetic groups. The lower infl ammatory response was observed by gross observation and confirmed by the results of H&E staining and TEM observation. Besides, the proliferation of fibroblasts, the formation of granulation tissue, as well as the vascularization, were improved in group 6 compared to other diabetic groups. All results suggest that bioactive glass and Yunnan baiyao ointments can accelerate the recovery of diabetes-impaired skin wounds, and comparing to other diabetic groups, group 6(with 5% Yunnan baiyao) has better healing effect.
文摘The purpose of this research was to prepare machinable bioactive glass-ceramics by sol-gel method. A multi-component composite sol with great uniformity and stability was first prepared by a 2-step method. The composite sol was then transformed into gel by aging under different temperatures. The gel was dried finally by super critically drying method and sintered to obtain the machinable bioactive glass-ceramics. Effect of thermal treatment on crystallization of the glass-ceramics was investigated by X-ray diffraction (XRD) analysis. Microstructure of the glass-ceramics was observed by Scanning Electron Microscopy (SEM) and the mechanism of machinability was discussed. Phlogopite and hydroxylapatite were identified as main crystal phases by XRD analysis under thermal treatment at 750 ℃ and 950 ℃ for 1.5 h separately. The relative bulk density could achieve 99% under 1050 ℃ for 4 h. Microstructure of the glass-ceramics showed that the randomly distributed phlogopite and hydroxylapatite phases were favorable to the machinability of the glass-ceramics. A mean bending strength of about 160-180 MPa and a fracture toughness parameter K_ IC of about 2.1-2.3 were determined for the glass-ceramics.
基金Project(50771096) supported by the National Natural Science Foundation of China
文摘Bioactive and bioresorbable composite materials were fabricated from poly-L-lactide and bioactive glass (average particle size 6.8 μm) by a solvent evaporation technique.Cellular cultivation in vitro and MTT assay were conducted for evaluating the influence on morphology,growth and proliferation of cultured fibroblasts.The results of cytotoxicity testing show that cells cultured in extracts of PLLA/BG and on the surface of composites demonstrate normal growth and proliferation.The bioactive glass in PLLA composite facilitates both adhesion and proliferation of rat fibroblasts on PLLA/bioactive glass composite film.
基金supported by National Natural Science Foundation of China (Grant No.50872110)
文摘Coating the hydroxyapatite (HA) on the titanium alloy surface can obtain a bioactive implant with high mechanical properties.However,the bonding force between the titanium alloy and the HA was low due to their different coefficient of thermal expansion (CET).Preparing the multi-layer coating with alleviated thermal stress on titanium alloy substrate is few reported.Fabrication of a TiO2-bioactive glass (BG)-HA bioactive coating was proposed to solve this problem.A particular TiO2 surface was prepared on the titanium alloy substrate by micro-arc oxidation treatment.The BG and HA coating were coated onto the TiO2 surface in turn by using a sol-gel method.The microstructure,surface morphology and phase composition of the coatings were analyzed.The bonding force of coatings was investigated by the nick apparatus.In vitro dissolution was performed by soaking the TiO2-BG-HA coated samples into the simulated body fluid for various periods.Micro-structural observations indicated that no delamination and crack occurred at the interface of HA/BG and BG/TiO2.The bonding between the substrate and coating consists of the mechanical interaction and the chemical bonding.The bonding force could reach about 45 N.The TiO2-BG-HA coating displayed the excellent forming ability of bone-like apatite when it was soaked into the simulated body fluid.This work suggests an innovative way to reduce the internal stress among coatings through varying BG composition to adjust its CTE,so as to enhance the bonding force.
文摘The prevalence of cases of antibiotic resistant infections and the limited number of new antibiotics call for new strategies to prevent bacterial infections. In this study, we evaluate the effectiveness of three different compositions of bioactive glass, doped with silver as an antimicrobial agent for potential applications in preventing bacterial infections. The different glasses were formulated to dissolve and release silver at different rates enabling their use in different applications either individually or in combination to achieve a desired effect. Silver oxide (Ag<sub>2</sub>O) was incorporated into various glass formulations and antibacterial effectiveness was measured using radius of inhibition. Each silver-doped glass effectively inhibited the growth of <i>Escherichia coli</i>, <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i> with radius of inhibition correlating directly with the dissolution rate of the glass—the faster dissolving glass producing the larger radius of inhibition. Suspending particles of the silver containing glass in phosphate buffered saline or fetal calf serum, slowed the dissolution of each glass and extended the effectiveness of the silver containing glass over time (based on size of the radius of inhibition) compared to water. Potential applications of the powdered glass formulations would be to incorporate glasses with different properties into coatings or cosmetics. To investigate the feasibility of these applications, the silver-glass powder was incorporated into polycaprolactone polymer to determine the antibacterial properties of the imbedded glass powder. Based on this investigation, the silver glass formulations reported herein have potential applications in the medical device, dental, pharmaceutical and cosmetic industries.
文摘Bioactive glass ceramic with SiO2-Ca2O-Na2O-P2O5 composition was prepared by the sol-gel method using sodium metasilicate (Na2SiO3) as silica source. The monolith obtained was sintered at 1000?C for 2 hours after which X-ray diffraction (XRD) analysis showed presence of combeite (Na2Ca2Si3O9) as the crystalline phase. In vitro bioactivity test conducted on the material using simulated body fluid (SBF) showed the formation of carbonated hydroxyapatite on its surface. The material during the SBF test was observed to transform from a mechanically strong crystalline phase Na2Ca2Si3O9 to an amorphous phase after incubation for 14 days indicating that the material was biodegradable. Scanning electron microscopy (SEM) was used to investigate the surface morphology, while Fourier transform infrared (FTIR) spectroscopy facilitated the confirmation of hydroxyapatite (HA) formation. The monolith material obtained may be a good candidate for application in tissue engineering scaffolds.
基金Project(50174059) supported by the National Natural Science Foundation of China
文摘Porous sol-gel glass of CaO-SiO2-P2O5 system with macropores larger than 100 μm was prepared by adding stearic acid as pore former when the sintering was carried out at 700 ℃ for 3h.The sol-gel porous glass shows an amorphous structure. The diameter of the pore created by pore former varies from 100 to 300 μm, and macroporous glass has a narrow and small pore size distribution in mesoporous scale. The porosity and pore size of macroporous bioactive glass can be controlled.
文摘Glass-ceramic samples, having composition of SiO<sub>2</sub>-35, CaO-45, Na<sub>2</sub>O-10 and P<sub>2</sub>O<sub>5</sub>-10 in weight ratio were prepared through sintering route. Glass powder was reinforced by Al powder. The strength of glass-ceramic composite was found to be temperature dependent, and it varies with the addition of Al powder. Flexural strength increases with the increase of powder addition and sintering temperature, however, decreases with the increase of sintering time. There is an optimum temperature (>1100℃) above which flexural strength of all samples decreases. Bulk density changes to a higher value as the addition of Al-powder increases up to 3% by weight above which density decreases slowly. On the other hand, apparent porosity and water absorption decrease with the increase of percentage of Al powder added. Porosity and water absorption also showed a dependent characteristic on sintering time and sintering temperature.
