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1、摘要近年來,生物可降解高分子材料在材料科學(xué)和生物醫(yī)學(xué)領(lǐng)域得到了廣泛的應(yīng)用。聚乳酸(PLA)是~種無毒、可完全降解的聚合物,不僅具有較好的化學(xué)惰性、易加工性,而且還具有良好的生物相容性,在生物醫(yī)學(xué)領(lǐng)域受到廣泛重視。聚乙二醇(PEG)具有良好的親水性和生物相容性,能夠抗蛋白質(zhì)吸附,是一種優(yōu)良的生物醫(yī)學(xué)材料。但二者各有其局限性:聚乳酸是疏水性物質(zhì),降低了其生物相容性;而聚乙二醇的降解性較差。人們通過各種手段將PLA與PEG復(fù)合,使兩者在性能上互補(bǔ),以獲得性能更加優(yōu)異的生物醫(yī)學(xué)材料。本文選用L.乳酸、1,6.己二醇、三
2、羥甲基丙烷和季戊四醇為原料,以氯化亞錫為催化劑,通過直接熔融縮聚法,制備了一系列端基結(jié)構(gòu)及分子量各不相同的線形、支鏈形及星形結(jié)構(gòu)的端羥基聚乳酸(PLLA.oH),進(jìn)一步與丙烯酰氯反應(yīng),得到了相應(yīng)的聚乳酸丙烯酸酯(PLLA.AC)。在此基礎(chǔ)上,將PLLA.AC和聚乙二醇雙丙烯酸酯(PEG.DA)按照不同配比,在光引發(fā)劑2,2.二甲氧基.2一苯基苯乙酮(DMPA)作用下,經(jīng)紫外光照射制得PLLA—PEG凝膠薄膜。利用IR、1H.NMR、GPC和XRD等對(duì)PLLA.OH和PLLA.AC的結(jié)構(gòu)和性質(zhì)進(jìn)行分析;利用XRD
3、、拉力機(jī)和SEM等對(duì)PLLA.PEG凝膠薄膜的結(jié)晶性能、力學(xué)性能和內(nèi)部形態(tài)進(jìn)行了分析,并對(duì)薄膜的溶脹性能、降解性能和藥物釋放性能進(jìn)行了詳細(xì)地研究。結(jié)果表明,通過改變PLLA.AC的結(jié)構(gòu)、分子量以及PLLA.AC與PEG.DA的配比,可以調(diào)節(jié)PLLA.PEG光聚合水凝膠薄膜的各項(xiàng)性質(zhì),并使其成為一種具有優(yōu)良性能和應(yīng)用前景的生物材料。關(guān)鍵詞:聚乳酸;聚乙二醇:光聚合:水凝膠;藥物釋放ABSTRACTThebiodegradablepolymermaterialshavebeenwidelyinvestigateda
4、ndappliedinmateriaIscienceandbiomedicalfieldinrecentyears.Poly(L-lacticacid)hasbeenattachedmuchattentioninbiomaterialapplicationsowingtoitssafety,biodegradability,environmentalcompatibilityandSOon.However,itsclinicalapplicationsaresometimesinterferedwithhydr
5、ophobicproperty,whichcoulddecreasethebiocompatibility.Poly(ethyleneglyc01)isalsoanexcellentbiomaterialwithhydrophilicability,biocompatibilityandresistibilitytoproteinadsorptionandcelladhesion.PLLAisusuallymodifiedbyPEGtogetabettermaterial.whichcouldcombineth
6、eadvantagesofPLLAandPEGInthepaper,multi-hydroxylgroupsendedpoly(L—lacticacid)s(PLLA—OH)werepreparedusingL-lacticacidand1,6-hexanediol/2-ethyl一2-hydroxymethyl-1,3-propanediol
7、pentaerythritolbydirectpolycondensation.Afterward。acrylatedpoly(L-lacticacid)s(PLLA-
8、AC)weregainedthroughthereactionofPLLA-OHsandacryloylchloride.Furthermore,aseriesofPLLA-PEGhydrogelfilmswereformedbyUVphotopolymerizationusing2,2-dimethoxy-2一phenylacetophenone(DMPA)asinitiator.ThestructuresandpropertiesofPLLA—OHsandPLLA-ACswerecharacterizedb
9、yR1H—NMRGPCandXRD.ThepropertiesofPLLA—PEGhydrogelfilmsweremeasuredbyXRD,SEMandSOon.Besides,theswellingperformance,degradationanddrugreleasebehaviorsofPLLA—PEGhydrogelfilmswerealsostudiedindetail