Poly-L-lactide（PLLA） was synthesized by ring-opening polymerization fi＇om high purity L-lactide with tin octoate as initiator, and characterized by means of infi＇ared, and ^1H-nuclear magnetic resonance. The influ...Poly-L-lactide（PLLA） was synthesized by ring-opening polymerization fi＇om high purity L-lactide with tin octoate as initiator, and characterized by means of infi＇ared, and ^1H-nuclear magnetic resonance. The influences of initiator concentration, polymerization temperature and polymerization time on the viscosity average molecular mass of PLLA were investigated. The effects of different purification methods on the concentration of initiator and viscosity average molecular mass were also studied. PLLA with a viscosity average molecular mass of about 50.5×1^04 was obtained when polymerization was conducted for 24 h at 140℃ with the molar ratio of monomer to purification initator being 12 000. After purification, the concentration of tin octoate decreases; however, the effect of different purification methods on the viscosity average molecular mass of PLLA is different, and the obtained PLLA is a typical amorphous polymeric material. The crystallinity of PLLA decreases with the increase of viscosity average molecular mass.展开更多
After removal of the caries or diseased teeth,the alveolar ridge will undergo absorption and atrophy.When the amount of alveolar bone is insufficient,it will cause an inability to perform effective dental implant rest...After removal of the caries or diseased teeth,the alveolar ridge will undergo absorption and atrophy.When the amount of alveolar bone is insufficient,it will cause an inability to perform effective dental implant restoration.In order to control the absorption and promote the repair and regeneration of alveolar ridge,a method of implanting guided bone regeneration(GBR)membranes at the extraction site is often used.In this study,silk fibroin(SF)and poly-L-lactide lactone(PLCL)were used to prepare bilayered guided bone regeneration membranes,and its morphology,hydrophilicity,surface roughness and mechanical properties were studied.At the same time,the drug release behaviors and cell compatibility of the bilayered membranes were studied.The results showed that SF/PLCL bi-layered membranes had good mechanical properties and surface hydrophilicity,and the drug-loaded bi-layered membranes had good cell compatibility.The bilayered membranes fabricated in this study are of potential for applying in the oral health field to promote bone regeneration.展开更多
The biocompatibility of surface-modified biphasic calcium phosphate （mBCP）/poly-L-Lactide （PLLA） biocomposite was investigated through a series of experiments in vitro and in vivo. Acute toxicity and short term sy...The biocompatibility of surface-modified biphasic calcium phosphate （mBCP）/poly-L-Lactide （PLLA） biocomposite was investigated through a series of experiments in vitro and in vivo. Acute toxicity and short term systemic toxicity experiments revealed no toxicity of the materials. Hemolysis assay indicated the good blood compatibility of the composite. In cytotoxicity assay, L929 mouse fibroblasts could well differentiate and proliferate. Animal experiments in vivo were.performed by implanting the materials into rabbits muscle for 8 weeks. The decreasing of inflammatory cells, the building of fibrous tissue layer as well as the growing of blood cells into materials indicated the nontoxicity of the composite. Based on the experiment results, surfacemodified BCP/PLLA biocomposite is proven to have superior biocompatibility, which would be a promising bone repairing material.展开更多
A three-dimensional finite element analysis was conducted to evaluate the feasibility of predicting the flexural properties of hydroxyapatite-reinforced poly-L-lactide acid （HA/PLLA） biocomposite using three differe...A three-dimensional finite element analysis was conducted to evaluate the feasibility of predicting the flexural properties of hydroxyapatite-reinforced poly-L-lactide acid （HA/PLLA） biocomposite using three different schemes. The scheme 1, originated from a beam analysis, was used to determine the flexural modulus analytically while the scheme 2 and 3 were designed to have different loading and boundary conditions using a finite element cell modeling approach. An empirical approach using Chow＇s formula and experimental data were used for comparison with the predicted results. In order to reduce the computational time and save the storage space involved in determining the effect of varying particle volume fractions on the flexural properties of HA/PLLA, a superelement technique was applied. The results using the scheme 3 and the Chow＇s formula were found to be in reasonable agreement with experimental results over the range of particle volume fraction. In addition to the Chow＇s formula, local stress distribution and the failure processes in HA/PLLA were simulated using the finite element technique.展开更多
基金Project (50174059) supported by the National Natural Science Foundation of China
文摘Poly-L-lactide（PLLA） was synthesized by ring-opening polymerization fi＇om high purity L-lactide with tin octoate as initiator, and characterized by means of infi＇ared, and ^1H-nuclear magnetic resonance. The influences of initiator concentration, polymerization temperature and polymerization time on the viscosity average molecular mass of PLLA were investigated. The effects of different purification methods on the concentration of initiator and viscosity average molecular mass were also studied. PLLA with a viscosity average molecular mass of about 50.5×1^04 was obtained when polymerization was conducted for 24 h at 140℃ with the molar ratio of monomer to purification initator being 12 000. After purification, the concentration of tin octoate decreases; however, the effect of different purification methods on the viscosity average molecular mass of PLLA is different, and the obtained PLLA is a typical amorphous polymeric material. The crystallinity of PLLA decreases with the increase of viscosity average molecular mass.
基金Natural Science Foundation for Key Program of the Jiangsu Higher Education Institutions,China(No.19KJA610004)Natural Science Foundation of Jiangsu Province,China(No.BK20161254)+1 种基金China Postdoctoral Science Foundation(No.2019M651947)Mandatory Projects of Nantong Municipal Science and Technology Plan,China(No.JC2018004)
文摘After removal of the caries or diseased teeth,the alveolar ridge will undergo absorption and atrophy.When the amount of alveolar bone is insufficient,it will cause an inability to perform effective dental implant restoration.In order to control the absorption and promote the repair and regeneration of alveolar ridge,a method of implanting guided bone regeneration(GBR)membranes at the extraction site is often used.In this study,silk fibroin(SF)and poly-L-lactide lactone(PLCL)were used to prepare bilayered guided bone regeneration membranes,and its morphology,hydrophilicity,surface roughness and mechanical properties were studied.At the same time,the drug release behaviors and cell compatibility of the bilayered membranes were studied.The results showed that SF/PLCL bi-layered membranes had good mechanical properties and surface hydrophilicity,and the drug-loaded bi-layered membranes had good cell compatibility.The bilayered membranes fabricated in this study are of potential for applying in the oral health field to promote bone regeneration.
基金supported by Doctoral Fund of Ministry of Education of China under grant No.20060610024
文摘The biocompatibility of surface-modified biphasic calcium phosphate （mBCP）/poly-L-Lactide （PLLA） biocomposite was investigated through a series of experiments in vitro and in vivo. Acute toxicity and short term systemic toxicity experiments revealed no toxicity of the materials. Hemolysis assay indicated the good blood compatibility of the composite. In cytotoxicity assay, L929 mouse fibroblasts could well differentiate and proliferate. Animal experiments in vivo were.performed by implanting the materials into rabbits muscle for 8 weeks. The decreasing of inflammatory cells, the building of fibrous tissue layer as well as the growing of blood cells into materials indicated the nontoxicity of the composite. Based on the experiment results, surfacemodified BCP/PLLA biocomposite is proven to have superior biocompatibility, which would be a promising bone repairing material.
基金Project supported by the Research Committee of the Hong Kong Polytechnic University (No.G-YX34).
文摘A three-dimensional finite element analysis was conducted to evaluate the feasibility of predicting the flexural properties of hydroxyapatite-reinforced poly-L-lactide acid （HA/PLLA） biocomposite using three different schemes. The scheme 1, originated from a beam analysis, was used to determine the flexural modulus analytically while the scheme 2 and 3 were designed to have different loading and boundary conditions using a finite element cell modeling approach. An empirical approach using Chow＇s formula and experimental data were used for comparison with the predicted results. In order to reduce the computational time and save the storage space involved in determining the effect of varying particle volume fractions on the flexural properties of HA/PLLA, a superelement technique was applied. The results using the scheme 3 and the Chow＇s formula were found to be in reasonable agreement with experimental results over the range of particle volume fraction. In addition to the Chow＇s formula, local stress distribution and the failure processes in HA/PLLA were simulated using the finite element technique.
