简介:Thepurposeofthepresentstudywastosynthesizeanewcompositesscaffoldcontainingpoly(γ-benzyl-L-glutamate)modifiedhydroxyapatite/(poly(L-lacticacid))(PBLG-g-HA/PLLA)andtoinvestigatetheirinvitrobehaviouronbonemesenchymalstromalcells(BMSCs).TheresultsdemonstratedthatBMSCproliferationwassignificantlyincreasedonPBLG-g-HA/PLLAscaffoldsafter3and7dayspostseedingwhencomparedtoPLLAandHA/PLLAscaffolds.TheinvitroosteogenicdifferentiationalsofavouredthecompositePBLG-g-HA/PLLAscaffoldswhencomparedtocontrolsbysignificantlyincreasingRunx2,ALPorosteocalcinmRNAexpressionasassessedbyreal-timePCR.TheresultsillustratethepotentialofPBLG-g-HA/PLLAscaffoldsforbonetissueengineeringapplications.AndtheinvivotestingfurtherconfirmsthePBLG-gHA/PLLAscaffolds'potentioalforhealingcriticalbonedefects.
简介:Aseriesofcross-linkedhydrogelsforcolon-specificdrugdeliveryweresynthesizedbygraftcopolymerizationofChitosanandacrylicacidusingN,N'-methylene-bis-(acrylamide)asacross-linker.TheirswellingbehaviorindifferentpHbuffersolutionsandcolonicenzymaticdegradabilitywerestudied.TheobtainedresultsshowthatthesehydrogelshavegoodpHsensitivitywhichcanavoiddrugreleaseinstomach,andtheirswellingkineticsinstimulantintestinalenvironmentfollowsecond-orderswellingkineticsequation.Thefactorsinfluencingtheswellingkineticsincludethedegreeofcross-linkingandthecomposition,whichmaycontrolnoreleaseoralittleamountreleaseofdruginsidethehydrogelsinthesmallintestinebytailoringthesefactors.Thegelsaredegradablebycolonicenzymesandthereisacorrelativitybetweenthedegradationofnetworksandtheswellingdegreeofthegels,whichmaytriggerthereleaseofdruginthecolon.Thehydrogelsshowagreatpotentialfortheirapplicationinoralcolon-specificdrugdeliverysystem.
简介:通过自由基共聚的方法制备了聚偏氟乙烯-g-聚(N-异丙基丙烯酰胺)(PVDF—g-PNIPAAm)共聚物,进而采用浸没沉淀相转化法制备了PVDF—g—PNIPAAm共聚膜。采用超声时域反射法研究了不同凝固浴温度下PVDF—g-PNIPAAm的成膜动力学。结合PVDF—g—PNIPAAm的成膜动力学,研究了凝固浴温度对膜结构与性能的影响。结果表明,在不同凝固浴温度下,PVDF—g—PNIPAAm的成膜过程均由液液分相来控制,凝固浴温度为30℃时成膜时间最长,40℃时成膜时间最短;不同凝固浴温度下制备的PVDF—g—PNIPAAm共聚膜保持了PVDF的结晶特性,随着凝固浴温度的升高,结晶度降低。同PVDF—g—PNIPAAm共聚物相比,PNIPAAm在PVDF—g—PNIPAAm膜表面的含量更高,其中,30℃时所成膜表面的PNIPAAm含量最高。不同凝固浴温度下所成的膜均呈指状孔结构,其中,30℃下所成的膜指状孔最大,孔隙率最高。25℃下制备的PVDF—g—PNIPAAm膜具有明显的温度响应性能,其水通量在30℃附近有显著增加。