温敏性半乳糖基化壳聚糖水凝胶的制备及其对HL-7702细胞增殖行为影响的研究

以壳聚糖(CS)为原料,在1-乙基-3-(3-二甲胺丙基)碳-二亚胺盐酸盐(EDC.HCL)和N-羟基琥珀酰亚胺(NHS)的活化作用下,合成了半乳糖基化壳聚糖(GC)单体,并与N-异丙基丙烯酰胺(NIPAAm)反应,制备了温敏性半乳糖基化壳聚糖N-异丙基丙烯酰胺共聚水凝胶(Gal-CS-g-PNIPAAm).通过红外光谱(FTIR)、光电子能谱(XPS)和扫描电子显微镜(SEM)等测试方法对其成分和结构进行了表征,并对其溶胀率和表面亲疏水性进行了研究.在Gal-CS-g-PNIPAAm凝胶表面培养人正常肝细胞系(HL-7702),研究其生长、脱附及转载(再增殖)行为.结果表明Gal-CS-g-PNIPAAm水凝胶具有良好的温度响应性和生物相容性,与PNIPAAm水凝胶相比,Gal-CS-g-PNIPAAm凝胶表面更有利于HL-7702细胞增殖.将温度降低至临界温度(LCST,32.5℃)以下,细胞可以从凝胶表面自发脱附,与酶消化脱附相比,细胞损伤更少.Gal-CS-g-PNIPAAm凝胶表面脱附的细胞比PNIPAAm凝胶表面脱附的细胞活性更高,表明PNIPAAm水凝胶引入GC单体后,凝胶的生物相容性得到改善,且脱附后细胞的增殖活力明显增加.

THERMO-SENSITIVE GALACTOSYLATED CHITOSAN-gPOLY(N-ISOPROPYLACRYLAMIDE) HYDROGELS AND THEIR EFFECTS ON HL-7702 CELLS' BEHAVIORS

The galactosylated chitosan(GC) was synthesized by the reaction of the amino group of chitosan and carboxyl group of lactobionic acid under the activation of 1ethyl3-(3dimethyllaminopropyl)carbodiimide hydrochloride(EDC) and N-hydroxysulfosuccinimide sodium salt(NHS).Subsequently,thermo-sensitive galactosylated chitosan-graft-poly(N-isopropylacrylamide)(Gal-CS-g-PNIPAm) hydrogels were prepared via free radical polymerization method.The chemical composition and structure of the novel copolymer obtained were characterized by Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS) and scanning electron microscopy(SEM),respectively.Thermo-sensitive feature of the hydrogel was studied by measuring its swelling ratio and contact angle.The results showed that Gal-CS-g-PNIPAm hydrogels exhibited good temperature response.HL-7702 cell behaviors such as proliferation,detachment and cell transfer were carefully investigated via cell culture on the surface of Gal-CS-g-PNIPAAm hydrogels in vitro.The results indicated that Gal-CS-g-PNIPAAm hydrogel exhibited a good biocompatibility.HL-7702 cells cultured on this hydrogel surface proliferated better than on the PNIPAAm hydrogel.Besides,HL-7702 cells could spontaneously detach from the surface of the Gal-CS-g-PNIPAAm hydrogel by lowering the temperature below the LCST(32.5 ℃),and the detached cells showed less damage than those detached by enzymes from TCPS.Meanwhile,cells detached from Gal-CS-g-PNIPAAm hydrogel showed higher viability than those from the PNIPAAm hydrogel,suggesting that introduction of GC monomer to PNIPAAm hydrogel evidently improved the activity of the detached cells.