Laser powder bed fusion(LPBF)makes it possible for biodegradable zinc(Zn)to be used to produce customized orthopedic implants.In this research,we investigate the impact of laser power and scanning speed on the develop...Laser powder bed fusion(LPBF)makes it possible for biodegradable zinc(Zn)to be used to produce customized orthopedic implants.In this research,we investigate the impact of laser power and scanning speed on the development of surface quality,relative densification,and texture during LPBF of Zn implants.Increasing laser power was able to decrease melt viscosity and surface tension,which improved the metallurgical bonding between adjacent tracks.Uneven and twisted tracks also became continuous and straight.Scanning speed could controlmolten-pool temperature to restrain grain natural orientation,achieving various crystal orientations and a weakened texture.Importantly,it further avoided the thermal expansion and contraction caused by excessive energy storage and accumulation in the matrix,thus reducing the generation of high-dislocation density.As a result,by selecting a reasonable laser power and scanning speed,the LPBF parts exhibited a flat surface morphology and a high density over 99.5%.Their average hardness,mechanical strength,and elongation reached 50.2 HV,127.8 MPa,and 7.6%,respectively.Additionally,the parts displayed a moderate degradation rate and excellent osteogenic properties.All these results provide a basis for selecting process parameters to optimize the comprehensive properties of LPBF-processed Zn parts for biodegradable applications.展开更多
Biodegradable magnesium(Mg) and its alloy show huge potential as temporary bone substitute due to the favorable biocompatibility and mechanical compatibility. However, one issue deserves attention is the too fast degr...Biodegradable magnesium(Mg) and its alloy show huge potential as temporary bone substitute due to the favorable biocompatibility and mechanical compatibility. However, one issue deserves attention is the too fast degradation. In this work, mesoporous bioglass(MBG)with high pore volume(0.59 cc/g) and huge specific surface area(110.78 m^(2)/g) was synthesized using improved sol-gel method, and introduced into Mg-based composite via laser additive manufacturing. Immersion tests showed that the incorporated MBG served as powerful adsorption sites, which promoted the in-situ deposition of apatite by successively adsorbing Ca2+and HPO42-. Such dense apatite film acted as an efficient protection layer and enhanced the corrosion resistance of Mg matrix, which was proved by the electrochemical impedance spectroscopy measurements. Thereby, Mg based composite showed a significantly decreased degradation rate of 0.31 mm/year. Furthermore,MBG also improved the mechanical properties as well as cell behavior. This work highlighted the advantages of MBG in the fabrication of Mg-based implant with enhanced overall performance for orthopedic application.展开更多
Hydroxyapatite(HA)nanoparticles and silver(Ag)nanoparticles are expected to enable desirable bioactivity and antibac-terial properties on biopolymer scaffolds.Nevertheless,interfacial adhesion between HA/Ag and the bi...Hydroxyapatite(HA)nanoparticles and silver(Ag)nanoparticles are expected to enable desirable bioactivity and antibac-terial properties on biopolymer scaffolds.Nevertheless,interfacial adhesion between HA/Ag and the biopolymer is poor due to the large physicochemical differences between these components.In this study,poly L-lactic acid(PLLA)powder was first surface-modified with bioactive polydopamine(PDA)in an alkaline environment.Next,HA and Ag nanoparticles were grown in situ on the PDA-coated PLLA powder,which was then adhered to the porous bone scaffold using a selective laser-sintering process.Results showed that HA and Ag nanoparticles were homogenously distributed in the matrix,with enhanced mechanical properties.Simulated body fluid bioactivity tests showed that the in situ grown HA-endowed scaffold shows excellent bioactivity.In vitro tests confirmed that the scaffold exhibits favorable biocompatibility with human umbilical cord mesenchymal stem cells,as well as strong antibacterial activity against Gram-negative Escherichia coli.Furthermore,in vivo assays indicated that the scaffold promoted bone generation,with a new bone area fraction of 71.8%after 8 weeks’implantation,without inflammation.展开更多
Mg alloys have been regarded as revolutionary metallic biomaterials for biodegradable bone implants,but their applications are mainly blocked by the too rapid degradation in physiological environment.This study explor...Mg alloys have been regarded as revolutionary metallic biomaterials for biodegradable bone implants,but their applications are mainly blocked by the too rapid degradation in physiological environment.This study explores the dual alloying effects of Mn and/or Sn on the performance of Mg alloys prepared by selective laser melting.The observed microstructure indicated remarkable refinement of both the grains and intermetallic phases in the Mn-and/or Sn-containing alloys during the rapid solidification process.Moreover,approximately a half decrease in corrosion rate was observed for AZ61-0.4Mn-0.8Sn alloy with respect to AZ61 alloy.The improved corrosion behavior was primarily due to the enhanced protective effects of surface layers,in which Mn-and/or Sn-rich phases acted as a helpful barrier against medium penetration and thereby alleviated the current exchange with the matrix.In addition,the solute Mn and/or Sn positively shifted the corrosion potential,which also brought about a better corrosion resistance.Furthermore,the strength and hardness of the alloys were also effectively improved and comparable to those of cortical bone.This could be ascribed to the dissolved Mn and/or Sn atoms and the finely dispersed intermetallic phases,which might cause lattice distortion and precipitation hardening.Besides,the Mn-and/or Sn-containing alloys showed good cytocompatibility as indicated by the normal morphology and increased viability of MG-63 cells.These findings suggest that the developed AZ61-Mn-Sn alloy is a promising candidate for biodegradable bone implants.展开更多
Bone biomaterials play a vital role in bone repair by providing the necessary substrate for cell adhesion, proliferation, and differentiation and by modulating cell activity and function. In past decades, extensive ef...Bone biomaterials play a vital role in bone repair by providing the necessary substrate for cell adhesion, proliferation, and differentiation and by modulating cell activity and function. In past decades, extensive efforts have been devoted to developing bone biomaterials with a focus on the following issues： （1） developing ideal biomaterials with a combination of suitable biological and mechanical properties; （2） constructing a cell microenvironment with pores ranging in size from nanoscale to submicro- and microscale; and （3） inducing the oriented differentiation of stem cells for artificial-to-biological transformation. Here we present a comprehensive review of the state of the art of bone biomaterials and their interactions with stem cells. Typical bone biomaterials that have been developed, including bioactive ceramics, biodegradable polymers, and biodegradable metals, are reviewed, with an emphasis on their characteristics and applications. The necessary porous structure of bone biomaterials for the cell microenvironment is discussed, along with the corresponding fabrication methods. Additionally, the promising seed stem cells for bone repair are summarized, and their interaction mechanisms with bone biomaterials are discussed in detail. Special attention has been paid to the signaling pathways involved in the focal adhesion and osteogenic differentiation of stem cells on bone biomaterials. Finally, achievements regarding bone biomaterials are summarized, and future research directions are proposed.展开更多
As two promising biomaterials for bone implants,biomedical metals have favorable mechanical properties and good machinability but lack of bioactivity;while bioceramics are known for good biocompatibility or even bioac...As two promising biomaterials for bone implants,biomedical metals have favorable mechanical properties and good machinability but lack of bioactivity;while bioceramics are known for good biocompatibility or even bioactivity but limited by their high brittleness.Biocermets,a kind of composites composing of bioceramics and biomedical metals,have been developed as an effective solution by combining their complementary advantages.This paper focused on the recently studied biocermets for bone implant applications.Concretely,biocermets were divided into ceramic-based biocermets and metal-based biocermets according to the phase percentages.Their characteristics were systematically summarized,and the fabrication methods for biocermets were reviewed and compared.Emphases were put on the interactions between bioceramics and biomedical metals,as well as the performance improvement mechanisms.More importantly,the main methods for the interfacial reinforcing were summarized,and the corresponding interfacial reinforcing mechanisms were discussed.In addition,the in vitro and in vivo biological performances of biocermets were also reviewed.Finally,future research directions were proposed on the advancement in component design,interfacial reinforcing and forming mechanisms for the fabrication of high-performance biocermets.展开更多
Biodegradable magnesium(Mg)alloy has been considered as a new generation of orthopedic implant ma-terial.Nevertheless,local corrosion usually occurs since the severe micro-galvanic behavior amongα-Mg and precipitates...Biodegradable magnesium(Mg)alloy has been considered as a new generation of orthopedic implant ma-terial.Nevertheless,local corrosion usually occurs since the severe micro-galvanic behavior amongα-Mg and precipitates,and results in too rapid degradation.In this study,porous Mg-Zn-Gd part was fabricated using laser additive manufacturing combined with solution heat treatment.During heat treatment,the precipitatedβ-(Mg,Zn)_(3) Gd phase dissolved inα-Mg,and reduced the energy threshold of stacking faults on basal planes,which finally triggered the formation of long period stacking ordered(LPSO)phase.The LPSO phases owned minor potential difference withα-Mg,thus causing less micro-galvanic corrosion ten-dency as compared toβ-(Mg,Zn)_(3) Gd phase.More importantly,they were uniformly distributed within theα-Mg grains and showed different orientations between adjacent grains.As a result,the LPSO-reinforced Mg-Zn-Gd tended to expand laterally during corrosion evolution,and achieved uniform degradation with a considerably reduced degradation rate of 0.34 mm/year.Moreover,in-vitro cell tests further proved its favorable biocompatibility.This work highlighted the additively manufactured Mg-Zn-Gd with LPSO structure showed great potential for orthopedic application.展开更多
The incorporation of hydroxyapatite(HAP)into poly-L-lactic acid(PLLA)matrix serving as bone scaffold is expected to exhibit bioactivity and osteoconductivity to those of the living bone.While too low degradation rate ...The incorporation of hydroxyapatite(HAP)into poly-L-lactic acid(PLLA)matrix serving as bone scaffold is expected to exhibit bioactivity and osteoconductivity to those of the living bone.While too low degradation rate of HAP/PLLA scaffold hinders the activity because the embedded HAP in the PLLA matrix is difficult to contact and exchange ions with body fluid.In this study,biodegradable polymer poly(glycolic acid)(PGA)was blended into the HAP/PLLA scaffold fabricated by laser 3D printing to accelerate the degradation.The results indicated that the incorporation of PGA enhanced the degradation rate of scaffold as indicated by the weight loss increasing from 3.3%to 25.0%after immersion for 28 days,owing to the degradation of high hydrophilic PGA and the subsequent accelerated hydrolysis of PLLA chains.Moreover,a lot of pores produced by the degradation of the scaffold promoted the exposure of HAP from the matrix,which not only activated the deposition of bone like apatite on scaffold but also accelerated apatite growth.Cytocompatibility tests exhibited a good osteoblast adhesion,spreading and proliferation,suggesting the scaffold provided a suitable environment for cell cultivation.Furthermore,the scaffold displayed excellent bone defect repair capacity with the formation of abundant new bone tissue and blood vessel tissue,and both ends of defect region were bridged after 8 weeks of implantation.展开更多
Zinc(Zn)possesses desirable degradability and favorable biocompatibility,thus being recognized as a promising bone implant material.Nevertheless,the insufficient mechanical performance limits its further clinical appl...Zinc(Zn)possesses desirable degradability and favorable biocompatibility,thus being recognized as a promising bone implant material.Nevertheless,the insufficient mechanical performance limits its further clinical application.In this study,reduced graphene oxide(RGO)was used as reinforcement in Zn scaffold fabricated via laser additive manufacturing.Results showed that the homogeneously dispersed RGO simultaneously enhanced the strength and ductility of Zn scaffold.On one hand,the enhanced strength was ascribed to(i)the grain refinement caused by the pinning effect of RGO,(ii)the efficient load shift due to the huge specific surface area of RGO and the favorable interface bonding between RGO and Zn matrix,and(iii)the Orowan strengthening by the homogeneously distributed RGO.On the other hand,the improved ductility was owing to the RGO-induced random orientation of grain with texture index reducing from 20.5 to 7.3,which activated more slip systems and provided more space to accommodate dislocation.Furthermore,the cell test confirmed that RGO promoted cell growth and differentiation.This study demonstrated the great potential of RGO in tailoring the mechanical performance and cell behavior of Zn scaffold for bone repair.展开更多
Zn has been regarded as new kind of potential implant biomaterials due to the desirable biodegradability and good biocompatibility,but the low strength and ductility limit its application in bone repairs.In the presen...Zn has been regarded as new kind of potential implant biomaterials due to the desirable biodegradability and good biocompatibility,but the low strength and ductility limit its application in bone repairs.In the present study,nano-SiC was incorporated into Zn matrix via laser melting,aiming to improve the mechanical performance.The microstructure analysis showed that nano-SiC distributed along Zn grain boundaries.During the laser rapid solidification,nano-SiC particles acted as the sites for heterogeneous nucleation,which resulted in the reduction of Zn grain size from 250μm to 15μm with 2 wt%SiC(Zn-2 SiC).Meanwhile,nano-SiC acted as a reinforcer by virtue of Orowan strengthening and dispersion strengthening.As a consequence,the nanocomposites showed maximal compressive yield strength(121.8±5.3 MPa)and high microhardness(72.24±3.01 HV),which were increased by 441%and 78%,respectively,compared with pure Zn.Moreover,fracture analysis indicated a more ductile fracture of the nanocomposites after the incorporation of nano-SiC In addition,the nanocomposites presented favorable biocompatibility and accelerated degradation caused by intergranular corrosion.These findings suggested that the nano-SiC reinforced Zn biocomposites may be the potential candidates for orthopedic implants.展开更多
Magnetostrictive alloys have attracted increasing attention in biomedical applications because of the ability to generate reversible deformation in the presence of external magnetic fields.This review focuses on the a...Magnetostrictive alloys have attracted increasing attention in biomedical applications because of the ability to generate reversible deformation in the presence of external magnetic fields.This review focuses on the advances in magnetostrictive alloys and their biomedical applications.The theories of magnetostriction are systematically summarized.The different types of magnetostrictive alloys and their preparation methods are also reviewed in detail.The magnetostrictive strains and phase compositions of typical magnetostrictive alloys,including iron based,rare-earth based and ferrite materials,are presented.Besides,a variety of approaches to preparing rods,blocks and films of magnetostriction materials,as well as the corresponding methods and setups for magnetostriction measurement,are summarized and discussed.Moreover,the interactions between magnetostrictive alloys and cells are analyzed and emphasis is placed on the transduction and transformation process of mechanochemical signals induced by magnetostriction.The latest applications of magnetostrictive alloys in remote microactuators,magnetic field sensors,wireless implantable devices and biodegradable implants are also reviewed.Furthermore,future research directions of magnetostrictive alloys are prospected with focus on their potential applications in remote cell actuation and bone repair.展开更多
Zn is a promising biodegradable metal owing to its moderate degradation rate and acceptable biocompatibility.However,the insufficient mechanical strength and plasticity of pure Zn limits its application in bone implan...Zn is a promising biodegradable metal owing to its moderate degradation rate and acceptable biocompatibility.However,the insufficient mechanical strength and plasticity of pure Zn limits its application in bone implants.In this study,a spiral eutectic structure is constructed in Zn-Mg-Ag alloys prepared via selective laser melting to improve their mechanical properties.Results show that the prepared Zn-Mg-Ag alloys are composed of a primary Zn matrix and a eutectic phase,which is composed of alternating𝛼-Zn and an intermetallic compound,MgZn 2.Moreover,the eutectic phase resembles a spiral and increases with Ag content in the alloys.The eutectic pinning effect hinders dislocation and hence results in dislocation accumulation.Meanwhile,the spiral structure alters the propagation direction and dissipates the propagation energy of cracks layer by layer.Consequently,a compressive strength of up to 309±15 MPa and an improved strain of 27%are exhibited in Zn-3Mg-1Ag alloy.Moreover,the Zn-Mg-Ag alloys show high biocompatibility with MG-63 cells and antibacterial activity against Escherichia coli.These findings indicate the potential of spiral eutectic structures for enhancing both the mechanical strength and plasticity of biodegradable Zn alloys.展开更多
基金The National Natural Science Foundation of China(Nos.51935014,52165043,52105352,and 82072084)Jiangxi Provincial Natural Science Foundation of China(No.20212BAB214026)+1 种基金The Project of State Key Laboratory of High Performance Complex ManufacturingThe Project of Science and Technology of Jiangxi Provincial Education Department(No.GJJ210835).
文摘Laser powder bed fusion(LPBF)makes it possible for biodegradable zinc(Zn)to be used to produce customized orthopedic implants.In this research,we investigate the impact of laser power and scanning speed on the development of surface quality,relative densification,and texture during LPBF of Zn implants.Increasing laser power was able to decrease melt viscosity and surface tension,which improved the metallurgical bonding between adjacent tracks.Uneven and twisted tracks also became continuous and straight.Scanning speed could controlmolten-pool temperature to restrain grain natural orientation,achieving various crystal orientations and a weakened texture.Importantly,it further avoided the thermal expansion and contraction caused by excessive energy storage and accumulation in the matrix,thus reducing the generation of high-dislocation density.As a result,by selecting a reasonable laser power and scanning speed,the LPBF parts exhibited a flat surface morphology and a high density over 99.5%.Their average hardness,mechanical strength,and elongation reached 50.2 HV,127.8 MPa,and 7.6%,respectively.Additionally,the parts displayed a moderate degradation rate and excellent osteogenic properties.All these results provide a basis for selecting process parameters to optimize the comprehensive properties of LPBF-processed Zn parts for biodegradable applications.
基金National Natural Science Foundation of China (51935014,52165043, 82072084, 81871498)Jiang Xi Provincial Natural Science Foundation of China (20192ACB20005,2020ACB214004)+6 种基金The Provincial Key R&D Projects of Jiangxi (20201BBE51012)Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme (2018)Shenzhen Science and Technology Plan Project (JCYJ20170817112445033)Innovation Team Project on University of Guangdong Province(2018GKCXTD001)Technology Innovation Platform Project of Shenzhen Institute of Information Technology 2020(PT2020E002)China Postdoctoral Science Foundation(2020M682114)Open Research Fund of Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology。
文摘Biodegradable magnesium(Mg) and its alloy show huge potential as temporary bone substitute due to the favorable biocompatibility and mechanical compatibility. However, one issue deserves attention is the too fast degradation. In this work, mesoporous bioglass(MBG)with high pore volume(0.59 cc/g) and huge specific surface area(110.78 m^(2)/g) was synthesized using improved sol-gel method, and introduced into Mg-based composite via laser additive manufacturing. Immersion tests showed that the incorporated MBG served as powerful adsorption sites, which promoted the in-situ deposition of apatite by successively adsorbing Ca2+and HPO42-. Such dense apatite film acted as an efficient protection layer and enhanced the corrosion resistance of Mg matrix, which was proved by the electrochemical impedance spectroscopy measurements. Thereby, Mg based composite showed a significantly decreased degradation rate of 0.31 mm/year. Furthermore,MBG also improved the mechanical properties as well as cell behavior. This work highlighted the advantages of MBG in the fabrication of Mg-based implant with enhanced overall performance for orthopedic application.
基金This study was supported by the following funds:(1)National Natural Science Foundation of China(Nos.51935014,82072084,and 81871498)(2)Jiangxi Provincial Natural Science Foundation of China(Nos.20192ACB20005 and 2020ACB214004)+6 种基金(3)The Provincial Key R&D Projects of Jiangxi(No.20201BBE51012)(4)Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2018)(5)Shenzhen Science and Technology Plan Project(No.JCYJ20170817112445033)(6)Innovation Team Project on University of Guangdong Province(No.2018GKCXTD001)(7)Technology Innovation Platform Project of Shenzhen Institute of Information Technology 2020(No.PT2020E002)(8)Open Research Fund of Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology(9)China Postdoctoral Science Foundation(No.2020M682114).
文摘Hydroxyapatite(HA)nanoparticles and silver(Ag)nanoparticles are expected to enable desirable bioactivity and antibac-terial properties on biopolymer scaffolds.Nevertheless,interfacial adhesion between HA/Ag and the biopolymer is poor due to the large physicochemical differences between these components.In this study,poly L-lactic acid(PLLA)powder was first surface-modified with bioactive polydopamine(PDA)in an alkaline environment.Next,HA and Ag nanoparticles were grown in situ on the PDA-coated PLLA powder,which was then adhered to the porous bone scaffold using a selective laser-sintering process.Results showed that HA and Ag nanoparticles were homogenously distributed in the matrix,with enhanced mechanical properties.Simulated body fluid bioactivity tests showed that the in situ grown HA-endowed scaffold shows excellent bioactivity.In vitro tests confirmed that the scaffold exhibits favorable biocompatibility with human umbilical cord mesenchymal stem cells,as well as strong antibacterial activity against Gram-negative Escherichia coli.Furthermore,in vivo assays indicated that the scaffold promoted bone generation,with a new bone area fraction of 71.8%after 8 weeks’implantation,without inflammation.
基金This study was supported by the following funds:(1)The Natural Science Foundation of China(51705540,51935014,51905553,81871494,81871498)Hunan Provincial Nat-ural Science Foundation of China(2018JJ3671,2019J50774,2019JJ50588)+3 种基金JiangXi Provincial Natural Science Foun-dation of China(20192ACB20005)Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2018)The Open Sharing Fund for the Large-scale Instruments and Equipments of Central South UniversityThe Project of Hunan Provincial Science and Technology Plan(2017RS3008).
文摘Mg alloys have been regarded as revolutionary metallic biomaterials for biodegradable bone implants,but their applications are mainly blocked by the too rapid degradation in physiological environment.This study explores the dual alloying effects of Mn and/or Sn on the performance of Mg alloys prepared by selective laser melting.The observed microstructure indicated remarkable refinement of both the grains and intermetallic phases in the Mn-and/or Sn-containing alloys during the rapid solidification process.Moreover,approximately a half decrease in corrosion rate was observed for AZ61-0.4Mn-0.8Sn alloy with respect to AZ61 alloy.The improved corrosion behavior was primarily due to the enhanced protective effects of surface layers,in which Mn-and/or Sn-rich phases acted as a helpful barrier against medium penetration and thereby alleviated the current exchange with the matrix.In addition,the solute Mn and/or Sn positively shifted the corrosion potential,which also brought about a better corrosion resistance.Furthermore,the strength and hardness of the alloys were also effectively improved and comparable to those of cortical bone.This could be ascribed to the dissolved Mn and/or Sn atoms and the finely dispersed intermetallic phases,which might cause lattice distortion and precipitation hardening.Besides,the Mn-and/or Sn-containing alloys showed good cytocompatibility as indicated by the normal morphology and increased viability of MG-63 cells.These findings suggest that the developed AZ61-Mn-Sn alloy is a promising candidate for biodegradable bone implants.
基金the Natural Science Foundation of China(51575537,81572577,and 51705540)the Hunan Provincial Natural Science Foundation of China(2016JJ1027)+4 种基金the Project of Innovation-driven Plan of Central South University(2016CX023)the Open-End Fund for the Valuable and Precision Instruments of Central South Universitythe Fund of the State Key Laboratory of Solidification Processing in NWPU(SKLSP201605)the National Postdoctoral Program for Innovative Talents(BX201700291)the Project of State Key Laboratory of High Performance Complex Manufacturing,Central South University
文摘Bone biomaterials play a vital role in bone repair by providing the necessary substrate for cell adhesion, proliferation, and differentiation and by modulating cell activity and function. In past decades, extensive efforts have been devoted to developing bone biomaterials with a focus on the following issues： （1） developing ideal biomaterials with a combination of suitable biological and mechanical properties; （2） constructing a cell microenvironment with pores ranging in size from nanoscale to submicro- and microscale; and （3） inducing the oriented differentiation of stem cells for artificial-to-biological transformation. Here we present a comprehensive review of the state of the art of bone biomaterials and their interactions with stem cells. Typical bone biomaterials that have been developed, including bioactive ceramics, biodegradable polymers, and biodegradable metals, are reviewed, with an emphasis on their characteristics and applications. The necessary porous structure of bone biomaterials for the cell microenvironment is discussed, along with the corresponding fabrication methods. Additionally, the promising seed stem cells for bone repair are summarized, and their interaction mechanisms with bone biomaterials are discussed in detail. Special attention has been paid to the signaling pathways involved in the focal adhesion and osteogenic differentiation of stem cells on bone biomaterials. Finally, achievements regarding bone biomaterials are summarized, and future research directions are proposed.
基金This study was supported by the following funds:The Natural Science Foundation of China(51705540,51935014,51905553,81871494,81871498)Hunan Provincial Natural Science Foundation of China(2020JJ3047,2018JJ3671,2019JJ50774,2019JJ50588)+6 种基金The Provincial Key R&D Projects of Jiangxi(20201BBE51012)JiangXi Provincial Natural Science Foundation of China(20192ACB20005)Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2018)The Project of Hunan Provincial Science and Technology Plan(2017RS3008)Shenzhen Science and Technology Plan Project(JCYJ20170817112445033)Innovation Team Project on University of Guangdong Province(2018GKCXTD001)Technology Innovation Platform Project of Shenzhen Institute of Information Technology 2020(PT2020E002).
文摘As two promising biomaterials for bone implants,biomedical metals have favorable mechanical properties and good machinability but lack of bioactivity;while bioceramics are known for good biocompatibility or even bioactivity but limited by their high brittleness.Biocermets,a kind of composites composing of bioceramics and biomedical metals,have been developed as an effective solution by combining their complementary advantages.This paper focused on the recently studied biocermets for bone implant applications.Concretely,biocermets were divided into ceramic-based biocermets and metal-based biocermets according to the phase percentages.Their characteristics were systematically summarized,and the fabrication methods for biocermets were reviewed and compared.Emphases were put on the interactions between bioceramics and biomedical metals,as well as the performance improvement mechanisms.More importantly,the main methods for the interfacial reinforcing were summarized,and the corresponding interfacial reinforcing mechanisms were discussed.In addition,the in vitro and in vivo biological performances of biocermets were also reviewed.Finally,future research directions were proposed on the advancement in component design,interfacial reinforcing and forming mechanisms for the fabrication of high-performance biocermets.
基金National Natural Science Foundation of China (Nos.51935014,52165043,82072084)JiangXi Provincial Natural Science Foundation of China (No.20212BAB214026)Jiangsu Provincial Key Research and Development Program (No.BE2019002).
文摘Biodegradable magnesium(Mg)alloy has been considered as a new generation of orthopedic implant ma-terial.Nevertheless,local corrosion usually occurs since the severe micro-galvanic behavior amongα-Mg and precipitates,and results in too rapid degradation.In this study,porous Mg-Zn-Gd part was fabricated using laser additive manufacturing combined with solution heat treatment.During heat treatment,the precipitatedβ-(Mg,Zn)_(3) Gd phase dissolved inα-Mg,and reduced the energy threshold of stacking faults on basal planes,which finally triggered the formation of long period stacking ordered(LPSO)phase.The LPSO phases owned minor potential difference withα-Mg,thus causing less micro-galvanic corrosion ten-dency as compared toβ-(Mg,Zn)_(3) Gd phase.More importantly,they were uniformly distributed within theα-Mg grains and showed different orientations between adjacent grains.As a result,the LPSO-reinforced Mg-Zn-Gd tended to expand laterally during corrosion evolution,and achieved uniform degradation with a considerably reduced degradation rate of 0.34 mm/year.Moreover,in-vitro cell tests further proved its favorable biocompatibility.This work highlighted the additively manufactured Mg-Zn-Gd with LPSO structure showed great potential for orthopedic application.
基金This work was supported by the following funds:(1)The Natural Science Foundation of China(51905553,51935014,81871494,81871498)(2)Hunan Provincial Natural Science Foundation of China(2019JJ50774,2019JJ50588)+5 种基金(3)The Provincial Key R&D Projects of Jiangxi(20201BBE51012)(4)JiangXi Provincial Natural Science Foundation of China(20192ACB20005)(5)Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2018)(6)The Project of Hunan Provincial Science and Technology Plan(2017RS3008)(7)The Project of State Key Laboratory of High Performance Complex Manufacturing,Central South University(8)Shenzhen Science and Technology Plan Project(JCYJ20170817112445033).
文摘The incorporation of hydroxyapatite(HAP)into poly-L-lactic acid(PLLA)matrix serving as bone scaffold is expected to exhibit bioactivity and osteoconductivity to those of the living bone.While too low degradation rate of HAP/PLLA scaffold hinders the activity because the embedded HAP in the PLLA matrix is difficult to contact and exchange ions with body fluid.In this study,biodegradable polymer poly(glycolic acid)(PGA)was blended into the HAP/PLLA scaffold fabricated by laser 3D printing to accelerate the degradation.The results indicated that the incorporation of PGA enhanced the degradation rate of scaffold as indicated by the weight loss increasing from 3.3%to 25.0%after immersion for 28 days,owing to the degradation of high hydrophilic PGA and the subsequent accelerated hydrolysis of PLLA chains.Moreover,a lot of pores produced by the degradation of the scaffold promoted the exposure of HAP from the matrix,which not only activated the deposition of bone like apatite on scaffold but also accelerated apatite growth.Cytocompatibility tests exhibited a good osteoblast adhesion,spreading and proliferation,suggesting the scaffold provided a suitable environment for cell cultivation.Furthermore,the scaffold displayed excellent bone defect repair capacity with the formation of abundant new bone tissue and blood vessel tissue,and both ends of defect region were bridged after 8 weeks of implantation.
基金The Natural Science Foundation of China(51935014,81871494,81871498)JiangXi Provincial Natural Science Foundation of China(20192ACB20005,2020ACB214004,20202BAB214011)+5 种基金The Provincial Key R&D Projects of Jiangxi(20201BBE51012)Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2018)The Project of Hunan Provincial Science and Technology Plan(2017RS3008)Shenzhen Science and Technology Plan Project(JCYJ20170817112445033)Innovation Team Project on University of Guangdong Province(2018GKCXTD001)Technology Innovation Platform Project of Shenzhen Institute of Information Technology 2020(PT2020E002).
文摘Zinc(Zn)possesses desirable degradability and favorable biocompatibility,thus being recognized as a promising bone implant material.Nevertheless,the insufficient mechanical performance limits its further clinical application.In this study,reduced graphene oxide(RGO)was used as reinforcement in Zn scaffold fabricated via laser additive manufacturing.Results showed that the homogeneously dispersed RGO simultaneously enhanced the strength and ductility of Zn scaffold.On one hand,the enhanced strength was ascribed to(i)the grain refinement caused by the pinning effect of RGO,(ii)the efficient load shift due to the huge specific surface area of RGO and the favorable interface bonding between RGO and Zn matrix,and(iii)the Orowan strengthening by the homogeneously distributed RGO.On the other hand,the improved ductility was owing to the RGO-induced random orientation of grain with texture index reducing from 20.5 to 7.3,which activated more slip systems and provided more space to accommodate dislocation.Furthermore,the cell test confirmed that RGO promoted cell growth and differentiation.This study demonstrated the great potential of RGO in tailoring the mechanical performance and cell behavior of Zn scaffold for bone repair.
基金supported financially by the National Natural Science Foundation of China (Nos.51705540,81871494 and 81871498)the Hunan Provincial Natural Science Foundation of China (Nos.2018JJ3671 and 2019JJ50588)+6 种基金the GuangdongProvince Higher Vocational Colleges & Schools Pearl River Scholar Funded Scheme (2018)the Open Sharing Fund for the Largescale Instruments and Equipments of Central South Universitythe Project of Hunan Provincial Science and Technology Plan (No.2017RS3008)the Shenzhen Science and Technology Plan Project (No.JCYJ20170817112445033)the National Postdoctoral Program for Innovative Talents (No.BX201700291)the Hunan Science and Technology Innovation Plan (Nos.2018SK2105 and kq1606001)the China Postdoctoral Science Foundation (No. 2018M632983)
文摘Zn has been regarded as new kind of potential implant biomaterials due to the desirable biodegradability and good biocompatibility,but the low strength and ductility limit its application in bone repairs.In the present study,nano-SiC was incorporated into Zn matrix via laser melting,aiming to improve the mechanical performance.The microstructure analysis showed that nano-SiC distributed along Zn grain boundaries.During the laser rapid solidification,nano-SiC particles acted as the sites for heterogeneous nucleation,which resulted in the reduction of Zn grain size from 250μm to 15μm with 2 wt%SiC(Zn-2 SiC).Meanwhile,nano-SiC acted as a reinforcer by virtue of Orowan strengthening and dispersion strengthening.As a consequence,the nanocomposites showed maximal compressive yield strength(121.8±5.3 MPa)and high microhardness(72.24±3.01 HV),which were increased by 441%and 78%,respectively,compared with pure Zn.Moreover,fracture analysis indicated a more ductile fracture of the nanocomposites after the incorporation of nano-SiC In addition,the nanocomposites presented favorable biocompatibility and accelerated degradation caused by intergranular corrosion.These findings suggested that the nano-SiC reinforced Zn biocomposites may be the potential candidates for orthopedic implants.
基金The Natural Science Foundation of China(51935014,82072084,81871498)Hunan Provincial Natural Science Foundation of China(2020JJ3047,2019JJ50588)+5 种基金The Provincial Key R&D Projects of Jiangxi(20201BBE51012)JiangXi Provincial Natural Science Foundation of China(20192ACB20005)National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials Open Fund,SCUT(2020004)Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2018)Innovation Team Project on University of Guangdong Province(2018GKCXTD001)Technology Innovation Platform Project of Shenzhen Institute of Information Technology(PT2020E002).
文摘Magnetostrictive alloys have attracted increasing attention in biomedical applications because of the ability to generate reversible deformation in the presence of external magnetic fields.This review focuses on the advances in magnetostrictive alloys and their biomedical applications.The theories of magnetostriction are systematically summarized.The different types of magnetostrictive alloys and their preparation methods are also reviewed in detail.The magnetostrictive strains and phase compositions of typical magnetostrictive alloys,including iron based,rare-earth based and ferrite materials,are presented.Besides,a variety of approaches to preparing rods,blocks and films of magnetostriction materials,as well as the corresponding methods and setups for magnetostriction measurement,are summarized and discussed.Moreover,the interactions between magnetostrictive alloys and cells are analyzed and emphasis is placed on the transduction and transformation process of mechanochemical signals induced by magnetostriction.The latest applications of magnetostrictive alloys in remote microactuators,magnetic field sensors,wireless implantable devices and biodegradable implants are also reviewed.Furthermore,future research directions of magnetostrictive alloys are prospected with focus on their potential applications in remote cell actuation and bone repair.
基金supported by Hunan Provincial Natural Science Foun-dation of China(Grant Nos.2020JJ3047,2019JJ50588)National Nat-ural Science Foundation of China(Grant Nos.51935014,82072084,81871498)+2 种基金Jiangxi Provincial Key R&D Projects of China(Grant No.20201BBE51012)Project of State Key Laboratory of High Performance Complex Manufacturing,National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials Open Fund,SCUT(Grant No.2020004)and Project of Hunan Provincial Innovation Foundation for Postgraduates(Grant No.CX20200187).
文摘Zn is a promising biodegradable metal owing to its moderate degradation rate and acceptable biocompatibility.However,the insufficient mechanical strength and plasticity of pure Zn limits its application in bone implants.In this study,a spiral eutectic structure is constructed in Zn-Mg-Ag alloys prepared via selective laser melting to improve their mechanical properties.Results show that the prepared Zn-Mg-Ag alloys are composed of a primary Zn matrix and a eutectic phase,which is composed of alternating𝛼-Zn and an intermetallic compound,MgZn 2.Moreover,the eutectic phase resembles a spiral and increases with Ag content in the alloys.The eutectic pinning effect hinders dislocation and hence results in dislocation accumulation.Meanwhile,the spiral structure alters the propagation direction and dissipates the propagation energy of cracks layer by layer.Consequently,a compressive strength of up to 309±15 MPa and an improved strain of 27%are exhibited in Zn-3Mg-1Ag alloy.Moreover,the Zn-Mg-Ag alloys show high biocompatibility with MG-63 cells and antibacterial activity against Escherichia coli.These findings indicate the potential of spiral eutectic structures for enhancing both the mechanical strength and plasticity of biodegradable Zn alloys.
