In this study, we developed a novel artificial nerve graft termed self-assembling peptide nanofiber scaffold （SAPNS）-containing poly（lactic-co-glycolic acid） （PLGA） conduit （SPC） and used it to bridge a 10-mm-...In this study, we developed a novel artificial nerve graft termed self-assembling peptide nanofiber scaffold （SAPNS）-containing poly（lactic-co-glycolic acid） （PLGA） conduit （SPC） and used it to bridge a 10-mm-long sciatic nerve defect in the rat. Retrograde tracing, behavioral testing and histomorphometric analyses showed that compared with the empty PLGA conduit implantation group, the SPC implantation group had a larger number of growing and extending axons, a markedly increased diameter of regenerated axons and a greater thickness of the myelin sheath in the conduit. Furthermore, there was an increase in the size of the neuromuscular junction and myofiber diameter in the target muscle. These findings suggest that the novel artificial SPC nerve graft can promote axonal regeneration and remyelination in the transected peripheral nerve and can be used for repairing peripheral nerve injury.展开更多
BACKGROUND： A degradable poly（lactic-co-glycolic acid） （PLGA） scaffold has been used to construct a degradable porous scaffold. This template can simulate the in vivo microenvironment and promote tissue formation...BACKGROUND： A degradable poly（lactic-co-glycolic acid） （PLGA） scaffold has been used to construct a degradable porous scaffold. This template can simulate the in vivo microenvironment and promote tissue formation. OBJECTIVE： To observe the histopathological changes during degeneration and regeneration of the intervertebral disc, and to analyze the effects of a PLGA scaffold on nerve fiber ingrowth into the lesion in vivo. DESIGN, TIME AND SETTING： A randomized, controlled animal experiment was performed at the Orthopaedic Laboratory, Clinic Medical Research Institution, Sir Run Run Shaw Hospital, Zhejiang University, from December 2007 to July 2008. MATERIALS： PLGA （China Textile Academy）; growth-associated protein-43 （Life-span, USA）; and protein gene product 9.5 antibody （AbD, United Kingdom） were used in this study. METHODS： Three consecutive segments of the intervertebral disc of thirty-two healthy adult male New Zealand rabbits were exposed, comprising L3-4, L4-5 and L5-6. Experimental intervertebral disc （L4-5 and L5-6） models were established by two different methods. In the test （trephine ＋ scaffold） group, a 5-mm deep hole was drilled into the annulus fibrosus using a 3-mm diameter trephine, and the PLGA scaffold was implanted into the hole. In the acupuncture group, the remaining experimental intervertebral disc annulus fibrosus was damaged using a 16G needle at a depth of 5 mm. The L3-4 disc served as a control. MAIN OUTCOME MEASURES： Intervertebral disc degeneration was assessed using radiography, magnetic resonance imaging, and histological examination at various time points post-surgery. Nerve fiber ingrowth into the degenerated intervertebral disc was observed using immunohistochemical staining for growth-associated protein-43 and protein gene product 9.5. RESULTS： Compared with the normal controls, the heights of the damaged intervertebral discs were decreased, and T2 signal intensity was decreased in the test and acupuncture groups 2 weeks post-surgery. Intervertebral disc degeneration was faster in the test group than in the acupuncture group. PLGA was coated with newly formed tissue, gradually degraded, and absorbed, and could induce tissue ingrowth deep into the annulus fibrosus. Results of immunohistochemical staining showed that nerve fibers were distributed in newly formed tissue in the test group, and in the superficial layer or surrounding scar tissue in the acupuncture group. CONCLUSION： A porous PLGA scaffold provides an important biological channel to induce nerve fiber ingrowth deep into the degenerated intervertebral disc.展开更多
The effect of Argon ion irradiation to the surface properties of poly(lactic-co-glycolic) acid (PLGA) was studied. A beam of 170 keV Argon ions was implanted at different fluencies (1 × 1012, 1 × 1013, 1 ...The effect of Argon ion irradiation to the surface properties of poly(lactic-co-glycolic) acid (PLGA) was studied. A beam of 170 keV Argon ions was implanted at different fluencies (1 × 1012, 1 × 1013, 1 × 1014, and 1 × 1015 ions/cm2). X-ray photoelectron spectroscopy (XPS) was used to analyze the evolution of the bonding microstructure of PLGA due to irradiation. Surface morphology was monitored using atomic force microscopy (AFM). AFM analysis shows that film roughness increased to maximum at the dose of 1 × 1014 ions/cm2 where the formations of hillocks were also detected. Hydrophilicity of PLGA is important for their applications in biomedicine such as bioscaffolds. Hydrophilicity was monitored using water contact angle measurements for both unmodified and ion-modified PLGA. It was observed that hydrophilicity of PLGA changes with the ion irradiation. This demonstrates that ion irradiation can be an alternative approach to control hydrophilicity of PLGA. PLGA scaffolds modified with ion irradiation could therefore be more suitable for the biomedical applications.展开更多
Background： Recently, local sustained-release antibiotics systems have been developed because they can increase local loci of concentrated antibiotics without increasing the plasma concentration, and thereby effectiv...Background： Recently, local sustained-release antibiotics systems have been developed because they can increase local loci of concentrated antibiotics without increasing the plasma concentration, and thereby effectively decrease any systemic toxicity and side effects. A vancomycin-loaded bone-like hydroxyapatite/poly-amino acid （V-BHA/PAA） bony scaffold was successfully fabricated with vancomycin-loaded poly lactic-co-glycolic acid microspheres and BHA/PAA, which was demonstrated to exhibit both porosity and perfect biodegradability. The aim of this study was to systematically evaluate the biosafety of this novel scaffold by conducting toxicity tests in vitro and in vivo. Methods： According to the ISO rules for medical implant biosafety, for in vitro tests, the scaffold was incubated with L929 fibroblasts or rabbit noncoagulant blood, with simultaneous creation of positive control and negative control groups. The growth condition ofL929 cells and hemolytic ratio were respectively evaluated after various incubation periods. For in vivo tests, a chronic osteomyelitis model involving the right proximal tibia of New Zealand white rabbits was established. After bacterial identification, the drug-loaded scaffold, drug-unloaded BHA/PAA, and poly （methyl methacrylate） were implanted, and a blank control group was also set up. Subsequently, the in vivo blood drug concentrations were measured, and the kidney and liver functions were evaluated. Results： In the in vitro tests, the cytotoxicity grades of V-BHA/PAA and BHA/PAA-based on the relative growth rate were all below 1. The hemolysis ratios of V-BHA/PAA and BHA/PAA were 2.27% and 1.42%, respectively, both below 5%. In the in vivo tests, the blood concentration of vancomycin after implantation of V-BHA/PAA was measured at far below its toxic concentration （60 mg/L）, and the function and histomorphology of the liver and kidney were all normal. Conclusion： According to ISO standards, the V-BHA/PAA scaffold is considered to have sufficient safety for clinical utilization.展开更多
Implant-associated infection remains a difficult medical problem in orthopedic surgery. Therefore, the development of multifunctional bone implants for treating infection and regenerating lost bone tissue, which may b...Implant-associated infection remains a difficult medical problem in orthopedic surgery. Therefore, the development of multifunctional bone implants for treating infection and regenerating lost bone tissue, which may be a result of infection, is important. In the present study, we report the fabrication of enoxacin- loaded poly （lactic-co-glycolic acid） （PLGA） coating on porous magnesium scaffold （Enox-PLGA-Mg） which combine the favorable properties of magnesium, the antibacterial property and the effect of inhibition of osteoclastic bone resorption of enoxacin. The drug loaded PLGA coating of Mg scaffold enables higher drug loading efficiency （52%-56%） than non-coating enoxacin loaded Mg scaffold （Enox-Mg） （4%-5%）. Enox- PLGA-Mg exhibits sustained drug release for more than 14 days, and this controlled release of enoxacin signifcantly inhibits bacterial adhesion and prevented biofilm formation by Staphylococcus epidermidis （ATCC35984） and Staphylococcus aureus （ATCC25923）. Biocompatibility tests with Balb/c mouse embryo fibroblasts （Balb/c 3T3 cells） indicate that PLGA-Mg has better biocompatibility than Mg. Finally, we also demonstrate that Enox-PLCA-Mg extract potently inhibited osteoclast formation in vitro. Therefore, Enox- PLCA-Mg has the potential to be used as a multifunctional controlled drug delivery system bone scaffolds to prevent and/or treat orthopedic peri-implant infections.展开更多
Tissue engineering scaffolds require a controlled pore size and interconnected pore structures to support the host tissue growth. In the present study, three dimensional （3D） hybrid scaffolds of poly lactic acid （...Tissue engineering scaffolds require a controlled pore size and interconnected pore structures to support the host tissue growth. In the present study, three dimensional （3D） hybrid scaffolds of poly lactic acid （PLA） and poly glycolic acid （PGA） were fabricated using solvent casting/particulate leaching. In this case, partially fused NaCl particles were used as porogen （200-300μ） to improve the overall porosity （≥90%） and internal texture of scaffolds. Differential scanning calorimeter （DSC） analysis of these porous scaffolds revealed a gradual reduction in glass transition temperature （Tg） （from 48°C to 42.5°C） with increase in hydrophilic PGA content. The potential applications of these scaffolds as implants were further tested for their biocompatibility and biodegradability in four simulated body fluid （SBF） types in vitro. Whereas, simulated body fluid （SBF） Type1 with the optimal amount of HCO 3 ions was found to be more appropriate and sensible for testing the bioactivity of scaffolds. Among three combinations of polymer scaffolds, sample B with a ratio of 75：25 of PLA： PGA showed greater stability in body fluids （pH 7.2） with an optimum degradation rate （9% to 12% approx）. X-ray diffractogram also confirmed a thin layer of hydroxyapatite deposition over sample B with all SBF types in vitro.展开更多
A degradable poly（lactic-co-glycolic acid, LA：GA=80：20）（PLGA） urethral tubular scaffold was fabricated by electrospinning. In order to enhance the mechanical properties, the scaffold was crosslinked with glutara...A degradable poly（lactic-co-glycolic acid, LA：GA=80：20）（PLGA） urethral tubular scaffold was fabricated by electrospinning. In order to enhance the mechanical properties, the scaffold was crosslinked with glutaraldehyde. The structure and properties of the crosslinked scaffolds were investigated by the mechanical property testing, scanning electron microscopy（SEM）, degradability test in vitro and 3-（4,5）-dimethylthiahiazo（-z-yl）-3,5-diphenytetrazo- liumromide（MTT）. The results show that the scaffold has the nano-structure. The pore size and the porosity are suitable for cell seeding, growth and extracellular matrix production. Although influenced by the crosslinking slightly, the pore size and the porosity could still support cell proliferation and tissuse formation. The mechanical properties are remarkably increased by the crosslinking of glutaraldehyde, and it could meet the demands of a urethral stent. The scaffold could completely collapse within 70 d. The results of the biocompatibility test show that the PLGA scaffold had no cytotoxicity.展开更多
In this study,mesoporous bioactive glass particles(MBGs) are incorporated into poly(lactic-co-glycolic acid)(PLGA) to fabricate highly interconnected macroporous composite scaffolds with enhanced mechanical and biolog...In this study,mesoporous bioactive glass particles(MBGs) are incorporated into poly(lactic-co-glycolic acid)(PLGA) to fabricate highly interconnected macroporous composite scaffolds with enhanced mechanical and biological properties via a developed supercritical carbon dioxide(scCO_(2)) foaming method Scaffolds show favorable highly interconnected and macroporous structure through a high foaming pressure and long venting time foaming strategy.Specifically,scaffolds with porosity from 73% to 85%,pore size from 120 μm to 320 μm and interconnectivity of over 95% are controllably fabricated at MBG content from 0 wt% to 20 wt%.In comparison with neat PLGA scaffolds,composite scaffolds perform improved strength(up to 1.5 folds) and Young's modulus(up to 3 folds).The interconnected macroporous structure is beneficial to the ingrowth of cells.More importantly,composite scaffolds also provide a more promising microenvironment for cellular proliferation and adhesion with the release of bioactive ions.Hopefully,MBG/PLGA scaffolds developed by the green foaming strategy in this work show promising morphological,mechanical and biological features for tissue regeneration.展开更多
The combination of micro-carriers and polymer scaffolds as promising bone grafts have attracted considerable interest in recent decades.The poly(L-lactic acid)/poly(lactic-co-glycolic acid)/polycaprolactone(PLLA/PLGA/...The combination of micro-carriers and polymer scaffolds as promising bone grafts have attracted considerable interest in recent decades.The poly(L-lactic acid)/poly(lactic-co-glycolic acid)/polycaprolactone(PLLA/PLGA/PCL)composite scaffold with porous structure was fabricated by thermally induced phase separation(TIPS).Dexamethasone(DEX)was incorporated into PLGA microspheres and then loaded on the PLLA/PLGA/PCL scaffoldtopreparethedesiredcompositescaffold.The physicochemical properties of the prepared composite scaffold were characterized.The morphology of rat bone marrow mesenchymal stem cells(BMSCs)grown on scaffolds was observed using scanning electron microscope(SEM)and fluorescence microscope.The resultsshowedthatthePLLA/PLGA/PCLscaffoldhad interconnected macropores and biomimetic nanofibrous structure.In addition,DEX can be released from scaffold in a sustained manner.More importantly,DEX loaded composite scaffold can effectively support the proliferation of BMSCs as indicated by fluorescence observation and cell proliferation assay.The results suggested that the prepared PLLA/PLGA/PCL composite scaffold incorporating drug-loaded PLGA microspheres could hold great potential for bone tissue engineering applications.展开更多
In recent years,much research has been suggested and examined for the development of tissue engineering scaffolds to promote cellular behaviors.In our study,RGD peptide and graphene oxide(GO)co-functionalized poly(lac...In recent years,much research has been suggested and examined for the development of tissue engineering scaffolds to promote cellular behaviors.In our study,RGD peptide and graphene oxide(GO)co-functionalized poly(lactide-co-glycolide,PLGA)(RGD-GO-PLGA)nanofiber mats were fabricated via electrospinning,and their physicochemical and thermal properties were characterized to explore their potential as biofunctional scaffolds for vascular tissue engineering.Scanning electron microscopy images revealed that the RGD-GO-PLGA nanofiber mats were readily fabricated and composed of randomoriented electrospun nanofibers with average diameter of 558nm.The successful co-functionalization of RGD peptide and GO into the PLGA nanofibers was confirmed by Fourier-transform infrared spectroscopic analysis.Moreover,the surface hydrophilicity of the nanofiber mats was markedly increased by co-functionalizing with RGD peptide and GO.It was found that the mats were thermally stable under the cell culture condition.Furthermore,the initial attachment and proliferation of primarily cultured vascular smoothmuscle cells(VSMCs)on the RGD-GO-PLGA nanofibermats were evaluated.It was revealed that the RGD-GO-PLGA nanofibermats can effectively promote the growth of VSMCs.In conclusion,our findings suggest that the RGD-GO-PLGA nanofiber mats can be promising candidates for tissue engineering scaffolds effective for the regeneration of vascular smooth muscle.展开更多
基金supported by a grant from the National Key Basic Research Program of China,No.2014CB542202 and 2014CB542205the National Natural Science Foundation of China,No.30973095&81371354+2 种基金a grant from Science and Technology Project of Guangzhou,in China,No.12C32121609the Natural Science Foundation of Guangdong Province of China,No.S2013010014697 to Guo JSHong Kong SCI Fund to Wu WT
文摘In this study, we developed a novel artificial nerve graft termed self-assembling peptide nanofiber scaffold （SAPNS）-containing poly（lactic-co-glycolic acid） （PLGA） conduit （SPC） and used it to bridge a 10-mm-long sciatic nerve defect in the rat. Retrograde tracing, behavioral testing and histomorphometric analyses showed that compared with the empty PLGA conduit implantation group, the SPC implantation group had a larger number of growing and extending axons, a markedly increased diameter of regenerated axons and a greater thickness of the myelin sheath in the conduit. Furthermore, there was an increase in the size of the neuromuscular junction and myofiber diameter in the target muscle. These findings suggest that the novel artificial SPC nerve graft can promote axonal regeneration and remyelination in the transected peripheral nerve and can be used for repairing peripheral nerve injury.
文摘BACKGROUND： A degradable poly（lactic-co-glycolic acid） （PLGA） scaffold has been used to construct a degradable porous scaffold. This template can simulate the in vivo microenvironment and promote tissue formation. OBJECTIVE： To observe the histopathological changes during degeneration and regeneration of the intervertebral disc, and to analyze the effects of a PLGA scaffold on nerve fiber ingrowth into the lesion in vivo. DESIGN, TIME AND SETTING： A randomized, controlled animal experiment was performed at the Orthopaedic Laboratory, Clinic Medical Research Institution, Sir Run Run Shaw Hospital, Zhejiang University, from December 2007 to July 2008. MATERIALS： PLGA （China Textile Academy）; growth-associated protein-43 （Life-span, USA）; and protein gene product 9.5 antibody （AbD, United Kingdom） were used in this study. METHODS： Three consecutive segments of the intervertebral disc of thirty-two healthy adult male New Zealand rabbits were exposed, comprising L3-4, L4-5 and L5-6. Experimental intervertebral disc （L4-5 and L5-6） models were established by two different methods. In the test （trephine ＋ scaffold） group, a 5-mm deep hole was drilled into the annulus fibrosus using a 3-mm diameter trephine, and the PLGA scaffold was implanted into the hole. In the acupuncture group, the remaining experimental intervertebral disc annulus fibrosus was damaged using a 16G needle at a depth of 5 mm. The L3-4 disc served as a control. MAIN OUTCOME MEASURES： Intervertebral disc degeneration was assessed using radiography, magnetic resonance imaging, and histological examination at various time points post-surgery. Nerve fiber ingrowth into the degenerated intervertebral disc was observed using immunohistochemical staining for growth-associated protein-43 and protein gene product 9.5. RESULTS： Compared with the normal controls, the heights of the damaged intervertebral discs were decreased, and T2 signal intensity was decreased in the test and acupuncture groups 2 weeks post-surgery. Intervertebral disc degeneration was faster in the test group than in the acupuncture group. PLGA was coated with newly formed tissue, gradually degraded, and absorbed, and could induce tissue ingrowth deep into the annulus fibrosus. Results of immunohistochemical staining showed that nerve fibers were distributed in newly formed tissue in the test group, and in the superficial layer or surrounding scar tissue in the acupuncture group. CONCLUSION： A porous PLGA scaffold provides an important biological channel to induce nerve fiber ingrowth deep into the degenerated intervertebral disc.
文摘The effect of Argon ion irradiation to the surface properties of poly(lactic-co-glycolic) acid (PLGA) was studied. A beam of 170 keV Argon ions was implanted at different fluencies (1 × 1012, 1 × 1013, 1 × 1014, and 1 × 1015 ions/cm2). X-ray photoelectron spectroscopy (XPS) was used to analyze the evolution of the bonding microstructure of PLGA due to irradiation. Surface morphology was monitored using atomic force microscopy (AFM). AFM analysis shows that film roughness increased to maximum at the dose of 1 × 1014 ions/cm2 where the formations of hillocks were also detected. Hydrophilicity of PLGA is important for their applications in biomedicine such as bioscaffolds. Hydrophilicity was monitored using water contact angle measurements for both unmodified and ion-modified PLGA. It was observed that hydrophilicity of PLGA changes with the ion irradiation. This demonstrates that ion irradiation can be an alternative approach to control hydrophilicity of PLGA. PLGA scaffolds modified with ion irradiation could therefore be more suitable for the biomedical applications.
基金This study was supported by a grant from the National Natural Science Foundation of China
文摘Background： Recently, local sustained-release antibiotics systems have been developed because they can increase local loci of concentrated antibiotics without increasing the plasma concentration, and thereby effectively decrease any systemic toxicity and side effects. A vancomycin-loaded bone-like hydroxyapatite/poly-amino acid （V-BHA/PAA） bony scaffold was successfully fabricated with vancomycin-loaded poly lactic-co-glycolic acid microspheres and BHA/PAA, which was demonstrated to exhibit both porosity and perfect biodegradability. The aim of this study was to systematically evaluate the biosafety of this novel scaffold by conducting toxicity tests in vitro and in vivo. Methods： According to the ISO rules for medical implant biosafety, for in vitro tests, the scaffold was incubated with L929 fibroblasts or rabbit noncoagulant blood, with simultaneous creation of positive control and negative control groups. The growth condition ofL929 cells and hemolytic ratio were respectively evaluated after various incubation periods. For in vivo tests, a chronic osteomyelitis model involving the right proximal tibia of New Zealand white rabbits was established. After bacterial identification, the drug-loaded scaffold, drug-unloaded BHA/PAA, and poly （methyl methacrylate） were implanted, and a blank control group was also set up. Subsequently, the in vivo blood drug concentrations were measured, and the kidney and liver functions were evaluated. Results： In the in vitro tests, the cytotoxicity grades of V-BHA/PAA and BHA/PAA-based on the relative growth rate were all below 1. The hemolysis ratios of V-BHA/PAA and BHA/PAA were 2.27% and 1.42%, respectively, both below 5%. In the in vivo tests, the blood concentration of vancomycin after implantation of V-BHA/PAA was measured at far below its toxic concentration （60 mg/L）, and the function and histomorphology of the liver and kidney were all normal. Conclusion： According to ISO standards, the V-BHA/PAA scaffold is considered to have sufficient safety for clinical utilization.
基金supported by the Key National Basic Research Program of China (Grant No. 2012CB619101)the National Natural Science Foundation of China (No. 81190133)+3 种基金the National Natural Science Foundation for the Youth of China (Grant Nos. 81401852 and 31500777)the Doctoral Innovation Fund Projects from Shanghai Jiao Tong University School of Medicine (No. BXJ201430)the Natural Science Foundation of Shanghai (No. 14ZR1424000)"Chen Guang" Project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation (No. 14CG14)
文摘Implant-associated infection remains a difficult medical problem in orthopedic surgery. Therefore, the development of multifunctional bone implants for treating infection and regenerating lost bone tissue, which may be a result of infection, is important. In the present study, we report the fabrication of enoxacin- loaded poly （lactic-co-glycolic acid） （PLGA） coating on porous magnesium scaffold （Enox-PLGA-Mg） which combine the favorable properties of magnesium, the antibacterial property and the effect of inhibition of osteoclastic bone resorption of enoxacin. The drug loaded PLGA coating of Mg scaffold enables higher drug loading efficiency （52%-56%） than non-coating enoxacin loaded Mg scaffold （Enox-Mg） （4%-5%）. Enox- PLGA-Mg exhibits sustained drug release for more than 14 days, and this controlled release of enoxacin signifcantly inhibits bacterial adhesion and prevented biofilm formation by Staphylococcus epidermidis （ATCC35984） and Staphylococcus aureus （ATCC25923）. Biocompatibility tests with Balb/c mouse embryo fibroblasts （Balb/c 3T3 cells） indicate that PLGA-Mg has better biocompatibility than Mg. Finally, we also demonstrate that Enox-PLCA-Mg extract potently inhibited osteoclast formation in vitro. Therefore, Enox- PLCA-Mg has the potential to be used as a multifunctional controlled drug delivery system bone scaffolds to prevent and/or treat orthopedic peri-implant infections.
文摘Tissue engineering scaffolds require a controlled pore size and interconnected pore structures to support the host tissue growth. In the present study, three dimensional （3D） hybrid scaffolds of poly lactic acid （PLA） and poly glycolic acid （PGA） were fabricated using solvent casting/particulate leaching. In this case, partially fused NaCl particles were used as porogen （200-300μ） to improve the overall porosity （≥90%） and internal texture of scaffolds. Differential scanning calorimeter （DSC） analysis of these porous scaffolds revealed a gradual reduction in glass transition temperature （Tg） （from 48°C to 42.5°C） with increase in hydrophilic PGA content. The potential applications of these scaffolds as implants were further tested for their biocompatibility and biodegradability in four simulated body fluid （SBF） types in vitro. Whereas, simulated body fluid （SBF） Type1 with the optimal amount of HCO 3 ions was found to be more appropriate and sensible for testing the bioactivity of scaffolds. Among three combinations of polymer scaffolds, sample B with a ratio of 75：25 of PLA： PGA showed greater stability in body fluids （pH 7.2） with an optimum degradation rate （9% to 12% approx）. X-ray diffractogram also confirmed a thin layer of hydroxyapatite deposition over sample B with all SBF types in vitro.
基金Supported by the National Natural Science Foundation of China(No. 50973043)
文摘A degradable poly（lactic-co-glycolic acid, LA：GA=80：20）（PLGA） urethral tubular scaffold was fabricated by electrospinning. In order to enhance the mechanical properties, the scaffold was crosslinked with glutaraldehyde. The structure and properties of the crosslinked scaffolds were investigated by the mechanical property testing, scanning electron microscopy（SEM）, degradability test in vitro and 3-（4,5）-dimethylthiahiazo（-z-yl）-3,5-diphenytetrazo- liumromide（MTT）. The results show that the scaffold has the nano-structure. The pore size and the porosity are suitable for cell seeding, growth and extracellular matrix production. Although influenced by the crosslinking slightly, the pore size and the porosity could still support cell proliferation and tissuse formation. The mechanical properties are remarkably increased by the crosslinking of glutaraldehyde, and it could meet the demands of a urethral stent. The scaffold could completely collapse within 70 d. The results of the biocompatibility test show that the PLGA scaffold had no cytotoxicity.
基金the National Natural Science Foundation of China (Grant No. 21676083)the Fundamental Research Funds for the Central Universities111 Project (Grant No. B20031)。
文摘In this study,mesoporous bioactive glass particles(MBGs) are incorporated into poly(lactic-co-glycolic acid)(PLGA) to fabricate highly interconnected macroporous composite scaffolds with enhanced mechanical and biological properties via a developed supercritical carbon dioxide(scCO_(2)) foaming method Scaffolds show favorable highly interconnected and macroporous structure through a high foaming pressure and long venting time foaming strategy.Specifically,scaffolds with porosity from 73% to 85%,pore size from 120 μm to 320 μm and interconnectivity of over 95% are controllably fabricated at MBG content from 0 wt% to 20 wt%.In comparison with neat PLGA scaffolds,composite scaffolds perform improved strength(up to 1.5 folds) and Young's modulus(up to 3 folds).The interconnected macroporous structure is beneficial to the ingrowth of cells.More importantly,composite scaffolds also provide a more promising microenvironment for cellular proliferation and adhesion with the release of bioactive ions.Hopefully,MBG/PLGA scaffolds developed by the green foaming strategy in this work show promising morphological,mechanical and biological features for tissue regeneration.
基金National Natural Science Foundations of China(Nos.31271028,31570984)Innovation Program of Shanghai Municipal Education Commission,China(No.13ZZ051)+2 种基金International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality,China(No.15540723400)Open Foundation of State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,China(No.LK1416)“111 Project” Biomedical Textile Materials Science and Technology,China(No.B07024)
文摘The combination of micro-carriers and polymer scaffolds as promising bone grafts have attracted considerable interest in recent decades.The poly(L-lactic acid)/poly(lactic-co-glycolic acid)/polycaprolactone(PLLA/PLGA/PCL)composite scaffold with porous structure was fabricated by thermally induced phase separation(TIPS).Dexamethasone(DEX)was incorporated into PLGA microspheres and then loaded on the PLLA/PLGA/PCL scaffoldtopreparethedesiredcompositescaffold.The physicochemical properties of the prepared composite scaffold were characterized.The morphology of rat bone marrow mesenchymal stem cells(BMSCs)grown on scaffolds was observed using scanning electron microscope(SEM)and fluorescence microscope.The resultsshowedthatthePLLA/PLGA/PCLscaffoldhad interconnected macropores and biomimetic nanofibrous structure.In addition,DEX can be released from scaffold in a sustained manner.More importantly,DEX loaded composite scaffold can effectively support the proliferation of BMSCs as indicated by fluorescence observation and cell proliferation assay.The results suggested that the prepared PLLA/PLGA/PCL composite scaffold incorporating drug-loaded PLGA microspheres could hold great potential for bone tissue engineering applications.
基金This study was supported by the Bio&Medical Technology Development Program of the National Research Foundation(NRF)funded by the Korean government(MEST)(No.2015M3A9E2028643)Basic Science Research Program through the NRF of Korea funded by the Ministry of Education(No.2016R1D1A1B03931076).
文摘In recent years,much research has been suggested and examined for the development of tissue engineering scaffolds to promote cellular behaviors.In our study,RGD peptide and graphene oxide(GO)co-functionalized poly(lactide-co-glycolide,PLGA)(RGD-GO-PLGA)nanofiber mats were fabricated via electrospinning,and their physicochemical and thermal properties were characterized to explore their potential as biofunctional scaffolds for vascular tissue engineering.Scanning electron microscopy images revealed that the RGD-GO-PLGA nanofiber mats were readily fabricated and composed of randomoriented electrospun nanofibers with average diameter of 558nm.The successful co-functionalization of RGD peptide and GO into the PLGA nanofibers was confirmed by Fourier-transform infrared spectroscopic analysis.Moreover,the surface hydrophilicity of the nanofiber mats was markedly increased by co-functionalizing with RGD peptide and GO.It was found that the mats were thermally stable under the cell culture condition.Furthermore,the initial attachment and proliferation of primarily cultured vascular smoothmuscle cells(VSMCs)on the RGD-GO-PLGA nanofibermats were evaluated.It was revealed that the RGD-GO-PLGA nanofibermats can effectively promote the growth of VSMCs.In conclusion,our findings suggest that the RGD-GO-PLGA nanofiber mats can be promising candidates for tissue engineering scaffolds effective for the regeneration of vascular smooth muscle.
