To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissueengineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared ...To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissueengineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared by three steps, i.e. solventcasting, compression molding and leaching stage. Factors influencing the compressive strength and the degradation behaviorof the porous scaffold, e.g. weight fraction of pore forming agent-sodium chloride (NaCl), weight ratio of PLLA: β-TCP,the particle size of β-TCP and the porosity, were discussed in details. Rat marrow stromal cells (RMSC) were incorporatedinto the composite by tissue engineering approach. Biological and osteogenesis potential of the composite scaffold weredetermined with MTT assay, alkaline phosphatase (ALP) activity and bone osteocalcin (OCN) content evaluation. Resultsshow that PLLA/β-TCP bioactive porous scaffold has good mechanical and pore structure with adjustable compressive strengthneeded for surgery. RMSCs seeding on porous PLLA/β-TCP composite behaves good seeding efficacy, biocompatibility andosteoinductive potential. Osteoprogenitor cells could well penetrate into the material matrix and begin cell proliferation andosteogenic differentiation. Osseous matrix could be formed on the surface of the composite after culturing in vitro. It isexpected that the PLLA/β-TCP porous composites are promising scaffolds for bone tissue engineering in prosthesis surgery.展开更多
Spherulitic morphology of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The morphology of spherulite of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The e...Spherulitic morphology of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The morphology of spherulite of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The effect of both annealing temperature and crystallization temperature on the formation of cracks was described by polarized optical microscope (POM). Non banded spherulite (fibrils) with cracks was detected in PLLA film after annealing at 160°C (180 min.) and isothermal crystallization temperatures at 140°C and 150°C. With increasing temperature after annealing treatment the size of spherulite is increased and more cracks are formed. The maximum growth rate of spherulites was found at 130°C. The physical ageing was carried out by annealing the PLLA sample at room temperature for several annealing time (ta) from 0 h to 720 h. The enthalpy relaxation has been studied by differential scanning calorimetry (DSC) through analysis of the endothermic peak of glass transition temperature, which increased and shifted towards higher temperature as the annealing time increased.展开更多
Highly porous ultrafine electrospun scaffolds,gelatin/poly(L-lactic acid)(PLLA) and chitosan/PLLA were prepared by blending gelatin and PLLA,chitosan and PLLA respectively.The biocompatibilities of these scaffolds wer...Highly porous ultrafine electrospun scaffolds,gelatin/poly(L-lactic acid)(PLLA) and chitosan/PLLA were prepared by blending gelatin and PLLA,chitosan and PLLA respectively.The biocompatibilities of these scaffolds were assessed by attachment,proliferation and viability of cells on them.The results indicated that over 30%WI-38 cells could attach to the gelatin/PLLA and chitosan/PLLA scaffolds at 2 h after seeding,while the attachment of the cells was only 15%on PLLA scaffolds.Both gelatin/PLLA and chitosan/PLLA scaffolds also exhibited a very good ability for proliferation of WI-38 cells.Cell growth on the gelatin/PLLA and chitosan /PLLA scaffolds showed dramatic improvement,indicating a much better biocompatibility in the blends contributed by gelatin and chitosan.3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay also demonstrated gelatin/PLLA showed better ability to enhance the growth and functions of the cells.These assays suggest that the electrospun gelatin/PLLA and chitosan/PLLA scaffolds are promising biomaterials with great biocompatibility for the development of skin tissue engineering.展开更多
基金This study was financially supported by 863 Hj-Tech ResearchDevelopment Program of China(2002AA326080)The Fund for Youth Teacher of Education Mlinistry of China(2002123).
文摘To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissueengineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared by three steps, i.e. solventcasting, compression molding and leaching stage. Factors influencing the compressive strength and the degradation behaviorof the porous scaffold, e.g. weight fraction of pore forming agent-sodium chloride (NaCl), weight ratio of PLLA: β-TCP,the particle size of β-TCP and the porosity, were discussed in details. Rat marrow stromal cells (RMSC) were incorporatedinto the composite by tissue engineering approach. Biological and osteogenesis potential of the composite scaffold weredetermined with MTT assay, alkaline phosphatase (ALP) activity and bone osteocalcin (OCN) content evaluation. Resultsshow that PLLA/β-TCP bioactive porous scaffold has good mechanical and pore structure with adjustable compressive strengthneeded for surgery. RMSCs seeding on porous PLLA/β-TCP composite behaves good seeding efficacy, biocompatibility andosteoinductive potential. Osteoprogenitor cells could well penetrate into the material matrix and begin cell proliferation andosteogenic differentiation. Osseous matrix could be formed on the surface of the composite after culturing in vitro. It isexpected that the PLLA/β-TCP porous composites are promising scaffolds for bone tissue engineering in prosthesis surgery.
文摘Spherulitic morphology of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The morphology of spherulite of pure poly lactic acid (PLLA) PLLA have investigated after thermal annealing. The effect of both annealing temperature and crystallization temperature on the formation of cracks was described by polarized optical microscope (POM). Non banded spherulite (fibrils) with cracks was detected in PLLA film after annealing at 160°C (180 min.) and isothermal crystallization temperatures at 140°C and 150°C. With increasing temperature after annealing treatment the size of spherulite is increased and more cracks are formed. The maximum growth rate of spherulites was found at 130°C. The physical ageing was carried out by annealing the PLLA sample at room temperature for several annealing time (ta) from 0 h to 720 h. The enthalpy relaxation has been studied by differential scanning calorimetry (DSC) through analysis of the endothermic peak of glass transition temperature, which increased and shifted towards higher temperature as the annealing time increased.
基金the Project of the Science and Technology Commission of Shanghai Municipality (No.Ilnm0505100)the China Postdoctoral Science Foundation(No.2012M510116)the Fundamental Research Funds for the Central Universities (No.0500219160)
文摘Highly porous ultrafine electrospun scaffolds,gelatin/poly(L-lactic acid)(PLLA) and chitosan/PLLA were prepared by blending gelatin and PLLA,chitosan and PLLA respectively.The biocompatibilities of these scaffolds were assessed by attachment,proliferation and viability of cells on them.The results indicated that over 30%WI-38 cells could attach to the gelatin/PLLA and chitosan/PLLA scaffolds at 2 h after seeding,while the attachment of the cells was only 15%on PLLA scaffolds.Both gelatin/PLLA and chitosan/PLLA scaffolds also exhibited a very good ability for proliferation of WI-38 cells.Cell growth on the gelatin/PLLA and chitosan /PLLA scaffolds showed dramatic improvement,indicating a much better biocompatibility in the blends contributed by gelatin and chitosan.3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay also demonstrated gelatin/PLLA showed better ability to enhance the growth and functions of the cells.These assays suggest that the electrospun gelatin/PLLA and chitosan/PLLA scaffolds are promising biomaterials with great biocompatibility for the development of skin tissue engineering.
