葡聚糖甲基丙烯酸甲酯水溶液的相变特性及其晶胶微球的制备

Phase Transition of Dextran Methacrylate Aqueous Solution and Preparation of Dextran-methacrylate-Based Cryogel Beads

葡聚糖衍生物作为组织工程支架载体和分离介质的基质材料,在生物医学工程和生物分离领域具有重要应用。晶胶介质是近几年研究的一种新型层析分离材料,但以葡聚糖衍生物为基质的晶胶介质则鲜有研究。今利用在线温度采集系统,通过测定葡聚糖甲基丙烯酸甲酯(Dex-MA)反应水溶液体系的冷冻曲线,研究了不同条件下该体系的液-固相变特性;并通过微流控聚焦成形方法,制备得到了以葡聚糖衍生物为基质的晶胶微球介质。结果表明,浓度为2%~10%(wt)葡聚糖甲基丙烯酸甲酯反应水溶液体系的结晶点温度在-0.54~0.25℃,起始结晶相变温度在-6.32^-13.26℃间随机分布;因此,维持冷冻温度约在-14℃以下,则可实现结晶相变致孔。以葡聚糖甲基丙烯酸甲酯反应水溶液体系为水相,乙酸乙酯溶液为油相,经微流控聚焦成形方法,于水相流速0.0054~0.0087 m×s^(-1)、油相流速0.0365~0.0433 m×s^(-1)下制备得到的葡聚糖衍生物晶胶微球,具有较均匀的粒径分布,平均粒径在1000~1400μm,随水相流速增大而增大,随油相流速增大而减小;其内部具有相互连通的超大孔隙,孔径尺寸为1~20μm。

Dextran derivatives are matrix materials of tissue engineering scaffolds and biological separation media,which have important applications in biomedical engineering and biological separation.Cryogels are new adsorption chromatography materials,but there are few studies on cryogels with dextran derivatives as matrix.In this study,an online temperature measurement system was used to measure freezing curves of dextran methacrylate aqueous solution under different conditions,and liquid-solid phase transition characteristics of the solution were investigated based on the freezing curves.Dextran methacrylate-based cryogel beads were then prepared by microfluidic focusing followed by cryopolymerization.The results show that the freezing point of dextran methacrylate aqueous solution(2%~10%(W/W))is in a range of-0.54~0.25℃,and the actual initial solvent crystallization temperature changes randomly from-6.32 to-13.26℃.Therefore,freezing temperature below-14℃is suitable to generate super-macropore within the beads by cryopolymerization.Dextran methacrylate aqueous solution was used as the aqueous phase and ethyl acetate solution as the oil phase,and cryogel beads with uniform particle size and average diameter of 1000~1400μm were prepared by maintaining the aqueous phase flow rates between 0.0054 and 0.0087 m·s-1 and the oil phase flow rates between 0.0365 and 0.0433 m·s-1.The bead diameter increases with the increase of the aqueous phase flow rates,while decreases with the increase of the oil phase flow rates.The super-macropore within these cryogel beads is well-interconnected and the pore size is approximately 1 to 20μm.