Ti-based scaffolds reinforced with zirconia and hydroxyapatite were produced successfully by a hybrid method with an eco-friendliness and low cost to obtain low elastic modulus(E) with sufficient physical, electrochem...Ti-based scaffolds reinforced with zirconia and hydroxyapatite were produced successfully by a hybrid method with an eco-friendliness and low cost to obtain low elastic modulus(E) with sufficient physical, electrochemical and biological properties. The effect of simultaneous modification of the volume fraction of hydroxyapatite(HA) and zirconia(ZrO_(2)) on scaffolds was investigated in terms of mechanical, corrosive, and antibacterial properties. Scanning electron microscopy with attached electron dispersive spectroscopy and X-ray diffraction were used for the characterization of scaffolds. Compression and electrochemical tests were performed to determine mechanical properties with detailed fracture mechanism and in-vitro corrosion susceptibility to simulated body fluid at 37 ℃,respectively. Antibacterial tests were carried out by comparing the inhibition areas of E.coli and S.aureus bacteria. It was observed that the mechanical strength of the scaffolds decreased with increasing HA:ZrO_(2)volume fraction ratio.The lowest E was achieved(6.61 GPa) in 6:4 HA:ZrO_(2)composite scaffolds. Corrosion current density(J_(corr)) values were calculated to be 21, 337, and 504 μ A/cm^(2) for unreinforced Ti, 3:2 and 6:4 HA:ZrO_(2)reinforced scaffolds,respectively. The inhibition capacity of the 6:4 reinforced composite scaffold was found to be more effective against S.aureus bacteria than other scaffolds.展开更多
A new scaffold has been developed,which made from poly(ε-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubula...A new scaffold has been developed,which made from poly(ε-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubular fabric. The aim of this paper is to study the variation tendency of the morphology and the mechanical properties of the sample with the changing of molecular weight. Weighing method was used to analyze the porosity of the sample,and scanning electron microscopy( SEM) images were taken to observe porous structure. The tensile and compressive strengths of the samples were tested by the universal mechanical tester and radial compression apparatus, respectively. And the results showed that the porosity and compressive strength were improved when increasing the molecular weight,and the elastic recovery rate was also improved slightly. However, molecular weight has little impact on the tensile strength properties,because the PET tubular fabric provides most of the strength support rather than PCL membrane.展开更多
A new entire biodegradable scaffold has been developed which does not require precellularization before transplantation.This new kind of vascular scaffold prototype made from porous poly-ε-caprolactone( PCL) membrane...A new entire biodegradable scaffold has been developed which does not require precellularization before transplantation.This new kind of vascular scaffold prototype made from porous poly-ε-caprolactone( PCL) membrane to provide three-dimensional environment for cell growth, and embedded with weft-knitted polylactic acid( PLA) fabric to support mechanics.The aim of this paper is to study the variation tendency of mechanical properties with the fabric spacing changing.The basic geometrical parameters were measured to characterize properties of the samples.The tensile and compressive elastic recovery of the samples were tested by the universal mechanical tester and radial compression apparatus,respectively.Both tensile and compressive properties enhanced when reducing the fabric spacing of the composite vascular scaffold.展开更多
A novel, Ti-6 Al-4 V(Ti64)/Hydroxyapatite(HA at 5% by weight concentration) metal/ceramic composite has been fabricated using electron beam powder bed fusion(EPBF) additive manufacturing(AM): specifically, the commerc...A novel, Ti-6 Al-4 V(Ti64)/Hydroxyapatite(HA at 5% by weight concentration) metal/ceramic composite has been fabricated using electron beam powder bed fusion(EPBF) additive manufacturing(AM): specifically, the commercial electron beam melting(EBM?) process. In addition to solid Ti64 and Ti64/5% HA samples, four different unit cell(model) open-cellular mesh structures for the Ti64/5% HA composite were fabricated having densities ranging from 0.68 to 1.12 g/cm^3, and corresponding Young's moduli ranging from 2.9 to 8.0 GPa, and compressive strengths ranging from ~3 to 11 MPa. The solid Ti64/5%HA composite exhibited an optimal tensile strength of 123 MPa, and elongation of 5.5% in contrast to a maximum compressive strength of 875 MPa. Both the solid composite and mesh samples deformed primarily by brittle deformation, with the mesh samples exhibiting erratic, brittle crushing. Solid, EPBF-fabricated Ti64 samples had a Vickers microindentation hardness of 4.1 GPa while the Ti64/5%HA solid composite exhibited a Vickers microindentation hardness of 6.8 GPa. The lowest density Ti64/5%HA composite mesh strut sections had a Vickers microindentation hardness of 7.1 GPa. Optical metallography(OM) and scanning electron microscopy(SEM) analysis showed the HA dispersoids to be highly segregated along domain or grain boundaries, but homogeneously distributed along alpha(hcp) platelet boundaries within these domains in the Ti64 matrix for both the solid and mesh composites. The alpha platelet width varied from ~5 μm in the EPBF-fabricated Ti64 to ~1.1 m for the Ti64/5%HA mesh strut. The precursor HA powder diameter averaged 5 μm, in contrast to the dispersed HA particle diameters in the Ti64/5%HA composite which averaged 0.5 m. This work highlights the use of EPBF AM as a novel process for fabrication of a true composite structure, consisting of a Ti64 matrix and interspersed and exposed HA domains, which to the authors' knowledge has not been reported before. The results also illustrate the prospects not only for fabricating specialized, novel composite bone replacement scaffolds and implants, through the combination of Ti64 and HA, but also prospects for producing a variety of related metal/ceramic composites using EPBF AM.展开更多
Mg-based porous materials,as potential bone tissue engineering scaffolds,are considered an attractive strategy for bone repair owing to favorable biodegradability,good biocompatibility and suitable mechanical properti...Mg-based porous materials,as potential bone tissue engineering scaffolds,are considered an attractive strategy for bone repair owing to favorable biodegradability,good biocompatibility and suitable mechanical properties.In this work,3D-cubic interconnected porous Mg–xZn–0.3Ca(x=0,3,6)scaffolds were prepared to obtain desirable pore structures with a mean porosity up to 73%and main pore size of 400–500μm,which pore structures were close to the human cancellous bone.The structure–property relationships in the present scaffolds were analyzed by experiments and theoretical models of generalized method of cells(GMC).Mg–xZn–0.3Ca scaffolds exhibited good compression properties with a maximum above 5MPa in yield strength and about 0.4GPa in elastic modulus.This was attributed to not only the alloy strengthening but also the large minimum solid area.On the other hand,the scaffolds showed undesirable and relatively serious degradation behavior in Hank’s solution,resulting from Zn addition in Mg-based scaffolds and the high surface area ratio in the pore structure.Therefore,surface modifications are worth studying for controlled degradation in the future.In conclusion,this research would explore a novel attempt to introduce 3D-cubic pore structure for Mg-based scaffolds,and provide new insights into the preparations of Mg-based scaffolds with good service performances for bone repair.展开更多
To improve the toughness of silk fibroin( SF) films,poly( ethylene glycol-glycerin)( PEGG) was synthesized with ethylene glycol and epichlorohydrin. The SF / PEGG blend films were prepared by casting aqueous solution ...To improve the toughness of silk fibroin( SF) films,poly( ethylene glycol-glycerin)( PEGG) was synthesized with ethylene glycol and epichlorohydrin. The SF / PEGG blend films were prepared by casting aqueous solution and their structures were characterized. The PEGG was in liquid state at room temperature so it will not be a single phrase at blend film. It crosslinked with SF and made it insolubility in water. The results of X-ray diffraction( XRD) indicated that the crystallinity of the SF in the blend films decreased with the content of PEGG increasing. The tensile strength and elongation at break of blend films were measured using an instron tensile tester. The results showed that the tensile strength and elongation at break of blend films were high enough for application.After the blend films were stored at room temperature for 100 d,the crystallinity, the tensile strength and elongation at wet state increased. The blend films are superior to SF films in providing excellent flexibility and mechanical properties in both dry and wet states. Based on the fact that SF has good biocompatibility,the SF /PEGG blend film will offer new options in many different biomedical applications.展开更多
In tissue engineering, microstructure and material composition of tissue scaffolds have major influences on the proliferation and differentiation of cells in the scaffolds. However, once tissue scaffolds implanted, it...In tissue engineering, microstructure and material composition of tissue scaffolds have major influences on the proliferation and differentiation of cells in the scaffolds. However, once tissue scaffolds implanted, it is extremely difficult to monitor the change of their microstructure and compositions during tissue regeneration. Here, we report how random lasing can be utilized to non-invasively monitor the structure and composition of scaffolds. We hypothesize that morphological and compositional change of silk fibroin (SF) scaffolds can be conveniently detected based on random lasing responses. Engineered SF scaffolds with hydroxyapatite (HAP) nanoparticles and controlled pore alignment were fabricated, and their random lasing responses were analyzed depending on the concentration of HAP nanoparticles and the degree of,:internal pore alignment. We also examined the real-time random lasing responses of porous SF scaffolds by applying a compressive force to' the scaffolds. Introduction of HAP nanoparticles lowered the lasing thresholds and narrowed the random lasing (RL) width dramatically, which :is likely due to the increase in heterogeneity in both refractive index and physical arrangement within the SF and HAP composites. The strong dependency of RL response on pore alignment was also measured and validated by numerical calculation with the finite element method (FEM).Finally, real-time monitoring of RL on compressed scaffolds demonstrated the possibility of using RL as a monitoring tool for structural change of SF scaffolds in vivo.展开更多
基金the financial supports from the Research Fund of Atatürk University, Turkey (No. FDK-2019-7281)。
文摘Ti-based scaffolds reinforced with zirconia and hydroxyapatite were produced successfully by a hybrid method with an eco-friendliness and low cost to obtain low elastic modulus(E) with sufficient physical, electrochemical and biological properties. The effect of simultaneous modification of the volume fraction of hydroxyapatite(HA) and zirconia(ZrO_(2)) on scaffolds was investigated in terms of mechanical, corrosive, and antibacterial properties. Scanning electron microscopy with attached electron dispersive spectroscopy and X-ray diffraction were used for the characterization of scaffolds. Compression and electrochemical tests were performed to determine mechanical properties with detailed fracture mechanism and in-vitro corrosion susceptibility to simulated body fluid at 37 ℃,respectively. Antibacterial tests were carried out by comparing the inhibition areas of E.coli and S.aureus bacteria. It was observed that the mechanical strength of the scaffolds decreased with increasing HA:ZrO_(2)volume fraction ratio.The lowest E was achieved(6.61 GPa) in 6:4 HA:ZrO_(2)composite scaffolds. Corrosion current density(J_(corr)) values were calculated to be 21, 337, and 504 μ A/cm^(2) for unreinforced Ti, 3:2 and 6:4 HA:ZrO_(2)reinforced scaffolds,respectively. The inhibition capacity of the 6:4 reinforced composite scaffold was found to be more effective against S.aureus bacteria than other scaffolds.
基金Fundamental Research Funds for the Central UniversitiesNational Natural Science Foundation of China(No.31100682)
文摘A new scaffold has been developed,which made from poly(ε-caprolactone)( PCL) membrane with porous structure,and reinforcement of PCL scaffold was achieved by embedding polyethylene terephthalate(PET) weft-knit tubular fabric. The aim of this paper is to study the variation tendency of the morphology and the mechanical properties of the sample with the changing of molecular weight. Weighing method was used to analyze the porosity of the sample,and scanning electron microscopy( SEM) images were taken to observe porous structure. The tensile and compressive strengths of the samples were tested by the universal mechanical tester and radial compression apparatus, respectively. And the results showed that the porosity and compressive strength were improved when increasing the molecular weight,and the elastic recovery rate was also improved slightly. However, molecular weight has little impact on the tensile strength properties,because the PET tubular fabric provides most of the strength support rather than PCL membrane.
基金the Fundamental Research Funds for the Central Universities,China，National Natural Science Foundation of China，"111 Project" Biomedical Textile Materials Science and Technology,China，the Donghua University Innovation Fund of Graduate Project,China
文摘A new entire biodegradable scaffold has been developed which does not require precellularization before transplantation.This new kind of vascular scaffold prototype made from porous poly-ε-caprolactone( PCL) membrane to provide three-dimensional environment for cell growth, and embedded with weft-knitted polylactic acid( PLA) fabric to support mechanics.The aim of this paper is to study the variation tendency of mechanical properties with the fabric spacing changing.The basic geometrical parameters were measured to characterize properties of the samples.The tensile and compressive elastic recovery of the samples were tested by the universal mechanical tester and radial compression apparatus,respectively.Both tensile and compressive properties enhanced when reducing the fabric spacing of the composite vascular scaffold.
文摘A novel, Ti-6 Al-4 V(Ti64)/Hydroxyapatite(HA at 5% by weight concentration) metal/ceramic composite has been fabricated using electron beam powder bed fusion(EPBF) additive manufacturing(AM): specifically, the commercial electron beam melting(EBM?) process. In addition to solid Ti64 and Ti64/5% HA samples, four different unit cell(model) open-cellular mesh structures for the Ti64/5% HA composite were fabricated having densities ranging from 0.68 to 1.12 g/cm^3, and corresponding Young's moduli ranging from 2.9 to 8.0 GPa, and compressive strengths ranging from ~3 to 11 MPa. The solid Ti64/5%HA composite exhibited an optimal tensile strength of 123 MPa, and elongation of 5.5% in contrast to a maximum compressive strength of 875 MPa. Both the solid composite and mesh samples deformed primarily by brittle deformation, with the mesh samples exhibiting erratic, brittle crushing. Solid, EPBF-fabricated Ti64 samples had a Vickers microindentation hardness of 4.1 GPa while the Ti64/5%HA solid composite exhibited a Vickers microindentation hardness of 6.8 GPa. The lowest density Ti64/5%HA composite mesh strut sections had a Vickers microindentation hardness of 7.1 GPa. Optical metallography(OM) and scanning electron microscopy(SEM) analysis showed the HA dispersoids to be highly segregated along domain or grain boundaries, but homogeneously distributed along alpha(hcp) platelet boundaries within these domains in the Ti64 matrix for both the solid and mesh composites. The alpha platelet width varied from ~5 μm in the EPBF-fabricated Ti64 to ~1.1 m for the Ti64/5%HA mesh strut. The precursor HA powder diameter averaged 5 μm, in contrast to the dispersed HA particle diameters in the Ti64/5%HA composite which averaged 0.5 m. This work highlights the use of EPBF AM as a novel process for fabrication of a true composite structure, consisting of a Ti64 matrix and interspersed and exposed HA domains, which to the authors' knowledge has not been reported before. The results also illustrate the prospects not only for fabricating specialized, novel composite bone replacement scaffolds and implants, through the combination of Ti64 and HA, but also prospects for producing a variety of related metal/ceramic composites using EPBF AM.
基金This work was supported by the National Key Research and Development Program of China(No.2016YFC1102402)the National Natural Science Foundation of China(No.51771054,No.51971062)+1 种基金the Science and Technology Project of Jiangsu Province(No.BE2019679)the Fundamental Research Funds for the Central Universities(No.2242018K3DN03,No.2242019K40057).
文摘Mg-based porous materials,as potential bone tissue engineering scaffolds,are considered an attractive strategy for bone repair owing to favorable biodegradability,good biocompatibility and suitable mechanical properties.In this work,3D-cubic interconnected porous Mg–xZn–0.3Ca(x=0,3,6)scaffolds were prepared to obtain desirable pore structures with a mean porosity up to 73%and main pore size of 400–500μm,which pore structures were close to the human cancellous bone.The structure–property relationships in the present scaffolds were analyzed by experiments and theoretical models of generalized method of cells(GMC).Mg–xZn–0.3Ca scaffolds exhibited good compression properties with a maximum above 5MPa in yield strength and about 0.4GPa in elastic modulus.This was attributed to not only the alloy strengthening but also the large minimum solid area.On the other hand,the scaffolds showed undesirable and relatively serious degradation behavior in Hank’s solution,resulting from Zn addition in Mg-based scaffolds and the high surface area ratio in the pore structure.Therefore,surface modifications are worth studying for controlled degradation in the future.In conclusion,this research would explore a novel attempt to introduce 3D-cubic pore structure for Mg-based scaffolds,and provide new insights into the preparations of Mg-based scaffolds with good service performances for bone repair.
基金National Natural Science Foundations of China(Nos.51203107,51373114)the Priority Academic Program Development ofJiangsu Higher Education Institutions,ChinaNatural Science Foundation of Jiangsu Province,China(No.BK20131176)
文摘To improve the toughness of silk fibroin( SF) films,poly( ethylene glycol-glycerin)( PEGG) was synthesized with ethylene glycol and epichlorohydrin. The SF / PEGG blend films were prepared by casting aqueous solution and their structures were characterized. The PEGG was in liquid state at room temperature so it will not be a single phrase at blend film. It crosslinked with SF and made it insolubility in water. The results of X-ray diffraction( XRD) indicated that the crystallinity of the SF in the blend films decreased with the content of PEGG increasing. The tensile strength and elongation at break of blend films were measured using an instron tensile tester. The results showed that the tensile strength and elongation at break of blend films were high enough for application.After the blend films were stored at room temperature for 100 d,the crystallinity, the tensile strength and elongation at wet state increased. The blend films are superior to SF films in providing excellent flexibility and mechanical properties in both dry and wet states. Based on the fact that SF has good biocompatibility,the SF /PEGG blend film will offer new options in many different biomedical applications.
基金the financial supports from the Guangzhou Municipal Science and Technology Project,China(No.202206010030)the Key R&D Program of Guangdong Province,China(No.2019B090904001)。
文摘In tissue engineering, microstructure and material composition of tissue scaffolds have major influences on the proliferation and differentiation of cells in the scaffolds. However, once tissue scaffolds implanted, it is extremely difficult to monitor the change of their microstructure and compositions during tissue regeneration. Here, we report how random lasing can be utilized to non-invasively monitor the structure and composition of scaffolds. We hypothesize that morphological and compositional change of silk fibroin (SF) scaffolds can be conveniently detected based on random lasing responses. Engineered SF scaffolds with hydroxyapatite (HAP) nanoparticles and controlled pore alignment were fabricated, and their random lasing responses were analyzed depending on the concentration of HAP nanoparticles and the degree of,:internal pore alignment. We also examined the real-time random lasing responses of porous SF scaffolds by applying a compressive force to' the scaffolds. Introduction of HAP nanoparticles lowered the lasing thresholds and narrowed the random lasing (RL) width dramatically, which :is likely due to the increase in heterogeneity in both refractive index and physical arrangement within the SF and HAP composites. The strong dependency of RL response on pore alignment was also measured and validated by numerical calculation with the finite element method (FEM).Finally, real-time monitoring of RL on compressed scaffolds demonstrated the possibility of using RL as a monitoring tool for structural change of SF scaffolds in vivo.
