To explore the ability of dihydroxyphenylalanine-insulin-like growth factor-1 (DOPA-IGF-1) coated hydroxyapatite/poly(lactic-co-glycolic acid)(HA/PLGA) microspheres to promote the proliferation and osteoclastic differ...To explore the ability of dihydroxyphenylalanine-insulin-like growth factor-1 (DOPA-IGF-1) coated hydroxyapatite/poly(lactic-co-glycolic acid)(HA/PLGA) microspheres to promote the proliferation and osteoclastic differentiation of rabbit bone mesenchymal stem cells(rBMSCs), HA/PLGA microspheres with different HA content (10%, 30%, 50%, mass fraction) were prepared by electrospinning method and HA/PLGA microspheres with 50% HA were coated with IGF-1 and DOPA-IGF-1, respectively. They were co-cultured with rBMSCs, respctively. Cell counting kit-8(CCK-8) detection, confocal laser scanning microscopy(CLSM), alkaline phosphatase(ALP) detection and osteogenesis related genes COL IA1, Runx2 and bone morphogenetic protein-2(BMP-2) detection were conducted to detect the proliferation activity, cell morphology, differentiation ability and the expression level of osteogenesis-related genes of cells cultured on all microspheres groups. The results showed that rBMSCs proliferation increased in an HA content dependent manner, and cells proliferated more in the IGF-1 coated and DOPA-IGF-1 coated groups, in particular in DOPA-IGF-1 coated group, and the differences were more remarkable over time (P<0.05). HA/PLGA microspheres promoted the proliferation and osteogenic differentiation of rBMSCs, and DOPA-IGF-1 coating enhanced the proliferation and osteogenic differentiation of rBMSCs.展开更多
Using ellipsometry, it is found the glass transition temperature of the spin-coated polyacrylamide （PAL） thin films on the supported silicon （Si） substrates with an oxide layer decreases with decreasing the film t...Using ellipsometry, it is found the glass transition temperature of the spin-coated polyacrylamide （PAL） thin films on the supported silicon （Si） substrates with an oxide layer decreases with decreasing the film thickness. But Tgs of the as- prepared thin films are much higher than that of the bulk sample. Such observations can be attributed to the combined result of the ＂surface effect＂ and increased hydrogen bonding interaction between PAL chains due to spin coating/thin film confinement.展开更多
In this paper,morphological structure,thermodynamic compatibility and relationship be-tween porosities and blend ratios of the wet coagulated PU/PVA sheets were studied by meansof observation of scanning electronic mi...In this paper,morphological structure,thermodynamic compatibility and relationship be-tween porosities and blend ratios of the wet coagulated PU/PVA sheets were studied by meansof observation of scanning electronic micrographies,tests of dynamic mechanical properties,moisture regain and vapor permeability.Furthermore,the formation of microvoids at interfacesof separated phases was discussed and a microvoid formation mechanism at phase interfaces ofhydrophobic-hydrophilic blends was suggested and compared with that ofhydrophobic-hydrophobic blends.展开更多
Ultra‐small metal nanoclusters have high surface energy and abundant active sites,and thereforetheir catalytic activities are usually significantly higher than those of larger nanoparticles.A temperature‐responsive ...Ultra‐small metal nanoclusters have high surface energy and abundant active sites,and thereforetheir catalytic activities are usually significantly higher than those of larger nanoparticles.A temperature‐responsive copolymer,namely poly(ethylene glycol)‐co‐poly(N‐isopropylacrylamide)(PEG‐PNIPAM)was synthesized as the first step,and then ultra‐small Pd clusters stabilized withinPEG‐PNIPAM copolymer micelles were formed by direct reduction.Pd nanoclusters of size less than2nm showed outstanding catalytic activity in the Suzuki coupling reaction.The reaction betweeniodobenzene and phenylboronic acid was completed in as little as10s(turnover frequency=4.3×104h?1).A yield of64%was achieved in5min in the reaction between chlorobenzene and phenylboronicacid.The catalyst showed significant deactivation during three consecutive runs.However,this composite catalyst consisting of Pd/PEG‐PNIPAM can be easily recycled based on the reversiblephase transition of temperature‐responsive PEG‐PNIPAM.This catalyst therefore has good potentialfor practical applications.展开更多
文摘To explore the ability of dihydroxyphenylalanine-insulin-like growth factor-1 (DOPA-IGF-1) coated hydroxyapatite/poly(lactic-co-glycolic acid)(HA/PLGA) microspheres to promote the proliferation and osteoclastic differentiation of rabbit bone mesenchymal stem cells(rBMSCs), HA/PLGA microspheres with different HA content (10%, 30%, 50%, mass fraction) were prepared by electrospinning method and HA/PLGA microspheres with 50% HA were coated with IGF-1 and DOPA-IGF-1, respectively. They were co-cultured with rBMSCs, respctively. Cell counting kit-8(CCK-8) detection, confocal laser scanning microscopy(CLSM), alkaline phosphatase(ALP) detection and osteogenesis related genes COL IA1, Runx2 and bone morphogenetic protein-2(BMP-2) detection were conducted to detect the proliferation activity, cell morphology, differentiation ability and the expression level of osteogenesis-related genes of cells cultured on all microspheres groups. The results showed that rBMSCs proliferation increased in an HA content dependent manner, and cells proliferated more in the IGF-1 coated and DOPA-IGF-1 coated groups, in particular in DOPA-IGF-1 coated group, and the differences were more remarkable over time (P<0.05). HA/PLGA microspheres promoted the proliferation and osteogenic differentiation of rBMSCs, and DOPA-IGF-1 coating enhanced the proliferation and osteogenic differentiation of rBMSCs.
基金financially supported by the National Natural Science Foundation of China(Nos.51173169 and 21004054)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,Human Resources,and Social Security Bureau of Zhejiang Province,China and the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD 1107037001)
文摘Using ellipsometry, it is found the glass transition temperature of the spin-coated polyacrylamide （PAL） thin films on the supported silicon （Si） substrates with an oxide layer decreases with decreasing the film thickness. But Tgs of the as- prepared thin films are much higher than that of the bulk sample. Such observations can be attributed to the combined result of the ＂surface effect＂ and increased hydrogen bonding interaction between PAL chains due to spin coating/thin film confinement.
文摘In this paper,morphological structure,thermodynamic compatibility and relationship be-tween porosities and blend ratios of the wet coagulated PU/PVA sheets were studied by meansof observation of scanning electronic micrographies,tests of dynamic mechanical properties,moisture regain and vapor permeability.Furthermore,the formation of microvoids at interfacesof separated phases was discussed and a microvoid formation mechanism at phase interfaces ofhydrophobic-hydrophilic blends was suggested and compared with that ofhydrophobic-hydrophobic blends.
基金supported by the National Natural Science Foundation of China (51502089,51302008)the Fundamental Research Funds for the Central Universities (2016MS03)~~
文摘Ultra‐small metal nanoclusters have high surface energy and abundant active sites,and thereforetheir catalytic activities are usually significantly higher than those of larger nanoparticles.A temperature‐responsive copolymer,namely poly(ethylene glycol)‐co‐poly(N‐isopropylacrylamide)(PEG‐PNIPAM)was synthesized as the first step,and then ultra‐small Pd clusters stabilized withinPEG‐PNIPAM copolymer micelles were formed by direct reduction.Pd nanoclusters of size less than2nm showed outstanding catalytic activity in the Suzuki coupling reaction.The reaction betweeniodobenzene and phenylboronic acid was completed in as little as10s(turnover frequency=4.3×104h?1).A yield of64%was achieved in5min in the reaction between chlorobenzene and phenylboronicacid.The catalyst showed significant deactivation during three consecutive runs.However,this composite catalyst consisting of Pd/PEG‐PNIPAM can be easily recycled based on the reversiblephase transition of temperature‐responsive PEG‐PNIPAM.This catalyst therefore has good potentialfor practical applications.
