Background Various tissue engineering strategies have been developed to facilitate axonal regeneration after spinal cord injury. This study aimed to investigate whether neural stem cells （NSCs） could survive in poly...Background Various tissue engineering strategies have been developed to facilitate axonal regeneration after spinal cord injury. This study aimed to investigate whether neural stem cells （NSCs） could survive in poly（L-lactic-co-glycolic acid） （PLGA） scaffolds and, when cografted with Schwann cells （SCs）, could be induced to differentiate towards neurons which form synaptic connection and eventually facilitate axonal regeneration and myelination and motor function. Methods NSCs and SCs which were seeded within the directional PLGA scaffolds were implanted in hemisected adult rat spinal cord. Control rats were similarly injured and implanted of scaffolds with or without NSCs. Survival, migration, differentiation, synaptic formation of NSCs, axonal regeneration and myelination and motor function were analyzed. Student＇s t test was used to determine differences in surviving percentage of NSCs. One-way analysis of variance （ANOVA） was used to determine the differences in the number of axons myelinated in the scaffolds, the mean latency and amplitude of cortical motor evoked potentials （CMEPs） and Basso, Beattie ＆ Bresnahan locomotor rating scale （BBB） score. The X2 test was used to determine the differences in recovery percentage of CMEPs. Results NSCs survived, but the majority migrated into adjacent host cord and died mostly. Survival rate of NSCs with SCs was higher than that of NSCs without SCs （（1.7831±0.0402）% vs. （1.4911±0.0313）%, P 〈0.001）. Cografted with SCs, NSCs were induced to differentiate towards neurons and might form synaptic connection. The mean number of myelinated axons in PLGA＋NSCs＋SCs group was more than that in PLGA＋NSCs group and in PLGA group （（110.25±30.46） vs. （18.25±3.30） and （11.25±5.54）, P 〈0.01）. The percentage of CMEPs recovery in PLGA＋NSCs＋SCs group was higher than in the other groups （84.8% vs, 50.0% and 37.5%, P 〈0.05）. The amplitude of CMEPs in PLGA＋NSCs＋SCs group was higher than in the other gro展开更多
Alginate microspheres were formed by coagulation of sodium alginate in CaCl 2 solutions,followed by lyophilization which could create the porous structure.Bovine serum albumin (BSA) was incorporated into the microsphe...Alginate microspheres were formed by coagulation of sodium alginate in CaCl 2 solutions,followed by lyophilization which could create the porous structure.Bovine serum albumin (BSA) was incorporated into the microspheres by mixing BSA with sodium alginate prior to coagulation.The release behavior of BSA from the Ca-alginate microspheres was studied.Further,the alginate microspheres loaded with BSA were embedded in PLGA films by mixing the alginate microspheres with PLGA solutions in order to study the sustained release of BSA from the PLGA film,which is widely used as cell scaffold materials in tissue engineering.The release behavior of BSA from the PLGA film embedded alginate microspheres indicated potential application for keeping the bioactivity of the growth factor.展开更多
Biodegradable Nanoparticles (NPs) are under intense investigation due to their potential application in targeted drug delivery. Upon their entry to the biological system, they encounter the immune system, which limits...Biodegradable Nanoparticles (NPs) are under intense investigation due to their potential application in targeted drug delivery. Upon their entry to the biological system, they encounter the immune system, which limits their availability at the intended site. Most importantly, the innate immune system is the one that acts as the first line of defense against foreign materials. It can be activated by collectin proteins which recognize the structural pattern of polysaccharide on the surface of microorganisms. NPs may interact with these proteins in a similar way, and the interaction may lead to beneficial outcomes in vaccine delivery. On the other hand, in targeted drug delivery, it is desirable for the NPs not to be recognized as foreign material as this may lead to their fast elimination from the system through mechanism such as opsonization. We investigated the interaction of PEGylated and un-PEGylated PLGA NPs with Recombinant Human Mannose-Binding Protein (HMBP) in an effort to understand the effect of surface modification on their binding to the protein. Results show that both PLGA-COOH and PLGA-PEG-NH2 bind to HMBP as studied using dynamic light scattering (DLS), fluoresce and UV-vis spectroscopy. However, their binding is shown to have different effect on the structure of the protein. Study done using fluorescence spectroscopy displayed a decrease in fluorescence emission of the protein upon binding to PLGA-COOH. On the other hand the fluorescence emission of the protein increased upon binding to the PLGA-PEG-NH2 indicating conformational changes in the protein structure.展开更多
首次以高分子量的聚(L-乳酸-co-乙醇酸)(PLLGA)和D-聚乳酸(PDLA)[m(PLLGA)∶m(PDLA)=3∶1,c 50 m L·g-1]为原料,氯仿为溶剂,等体积的甲醇为沉淀剂,于50℃蒸发4 h形成了PLLGA和PDLA的立构复合物(sc-PLA),其结构和性能经XRD,DSC和TG...首次以高分子量的聚(L-乳酸-co-乙醇酸)(PLLGA)和D-聚乳酸(PDLA)[m(PLLGA)∶m(PDLA)=3∶1,c 50 m L·g-1]为原料,氯仿为溶剂,等体积的甲醇为沉淀剂,于50℃蒸发4 h形成了PLLGA和PDLA的立构复合物(sc-PLA),其结构和性能经XRD,DSC和TGA表征。结果表明:sc-PLA的结晶度达96.2%,热失重5%温度为342℃(PLLGA为304℃)。展开更多
基金This work was supported by the grant from the International Cooperation Research Foundation of National Natural Science Foundation of China （No. 30540450581）. Conflict of interest： none.
文摘Background Various tissue engineering strategies have been developed to facilitate axonal regeneration after spinal cord injury. This study aimed to investigate whether neural stem cells （NSCs） could survive in poly（L-lactic-co-glycolic acid） （PLGA） scaffolds and, when cografted with Schwann cells （SCs）, could be induced to differentiate towards neurons which form synaptic connection and eventually facilitate axonal regeneration and myelination and motor function. Methods NSCs and SCs which were seeded within the directional PLGA scaffolds were implanted in hemisected adult rat spinal cord. Control rats were similarly injured and implanted of scaffolds with or without NSCs. Survival, migration, differentiation, synaptic formation of NSCs, axonal regeneration and myelination and motor function were analyzed. Student＇s t test was used to determine differences in surviving percentage of NSCs. One-way analysis of variance （ANOVA） was used to determine the differences in the number of axons myelinated in the scaffolds, the mean latency and amplitude of cortical motor evoked potentials （CMEPs） and Basso, Beattie ＆ Bresnahan locomotor rating scale （BBB） score. The X2 test was used to determine the differences in recovery percentage of CMEPs. Results NSCs survived, but the majority migrated into adjacent host cord and died mostly. Survival rate of NSCs with SCs was higher than that of NSCs without SCs （（1.7831±0.0402）% vs. （1.4911±0.0313）%, P 〈0.001）. Cografted with SCs, NSCs were induced to differentiate towards neurons and might form synaptic connection. The mean number of myelinated axons in PLGA＋NSCs＋SCs group was more than that in PLGA＋NSCs group and in PLGA group （（110.25±30.46） vs. （18.25±3.30） and （11.25±5.54）, P 〈0.01）. The percentage of CMEPs recovery in PLGA＋NSCs＋SCs group was higher than in the other groups （84.8% vs, 50.0% and 37.5%, P 〈0.05）. The amplitude of CMEPs in PLGA＋NSCs＋SCs group was higher than in the other gro
文摘Alginate microspheres were formed by coagulation of sodium alginate in CaCl 2 solutions,followed by lyophilization which could create the porous structure.Bovine serum albumin (BSA) was incorporated into the microspheres by mixing BSA with sodium alginate prior to coagulation.The release behavior of BSA from the Ca-alginate microspheres was studied.Further,the alginate microspheres loaded with BSA were embedded in PLGA films by mixing the alginate microspheres with PLGA solutions in order to study the sustained release of BSA from the PLGA film,which is widely used as cell scaffold materials in tissue engineering.The release behavior of BSA from the PLGA film embedded alginate microspheres indicated potential application for keeping the bioactivity of the growth factor.
文摘Biodegradable Nanoparticles (NPs) are under intense investigation due to their potential application in targeted drug delivery. Upon their entry to the biological system, they encounter the immune system, which limits their availability at the intended site. Most importantly, the innate immune system is the one that acts as the first line of defense against foreign materials. It can be activated by collectin proteins which recognize the structural pattern of polysaccharide on the surface of microorganisms. NPs may interact with these proteins in a similar way, and the interaction may lead to beneficial outcomes in vaccine delivery. On the other hand, in targeted drug delivery, it is desirable for the NPs not to be recognized as foreign material as this may lead to their fast elimination from the system through mechanism such as opsonization. We investigated the interaction of PEGylated and un-PEGylated PLGA NPs with Recombinant Human Mannose-Binding Protein (HMBP) in an effort to understand the effect of surface modification on their binding to the protein. Results show that both PLGA-COOH and PLGA-PEG-NH2 bind to HMBP as studied using dynamic light scattering (DLS), fluoresce and UV-vis spectroscopy. However, their binding is shown to have different effect on the structure of the protein. Study done using fluorescence spectroscopy displayed a decrease in fluorescence emission of the protein upon binding to PLGA-COOH. On the other hand the fluorescence emission of the protein increased upon binding to the PLGA-PEG-NH2 indicating conformational changes in the protein structure.
文摘首次以高分子量的聚(L-乳酸-co-乙醇酸)(PLLGA)和D-聚乳酸(PDLA)[m(PLLGA)∶m(PDLA)=3∶1,c 50 m L·g-1]为原料,氯仿为溶剂,等体积的甲醇为沉淀剂,于50℃蒸发4 h形成了PLLGA和PDLA的立构复合物(sc-PLA),其结构和性能经XRD,DSC和TGA表征。结果表明:sc-PLA的结晶度达96.2%,热失重5%温度为342℃(PLLGA为304℃)。
