In situ solidifying liquids for medical application.

液体材料可以在不破坏自然组织的情况下立即形成凝胶，将在许多医疗领域得到应用，如动静脉畸形(AVM)的治疗、止血和生物人工器官的制备。我们制备了不同的液体材料，并用动物模型检测了它们的效果。动静脉畸形：将聚(甲基丙烯酸异羟乙酯-甲基丙烯酸甲酯)溶于碘并加入少量乙醇制成栓塞液。还合成了2-氰基丙烯酸异硬脂酯用于包埋。这种新型栓塞液无细胞毒性，可以通过细长的导管注入动静脉畸形血管内，有效阻断动静脉畸形。止血剂：合成了N-羟基琥珀酰亚胺活化的L-谷氨酸(PLGA)。这种NHS激活的PLGA可以在水溶液中立即与明胶形成凝胶。这一发现有力地表明，这种明胶和NHS-PLGA作为止血剂和粘附剂的组合非常有希望，并有可能取代从人体血液成分制备的纤维蛋白胶。细胞包裹性：这种水凝胶是由丙烯酰胺和N，N‘-双丙烯酰胺自由基共聚合成的带有硫醇基团的聚丙烯酰胺衍生物，然后还原共聚物中的二硫键而得到的。这种水溶性的共聚物被用来通过在共聚物上重新形成二硫键来包裹仓鼠胰岛，以产生水凝胶。在体外检查时，水凝胶中的胰岛胰岛素释放持续了一个多月。

Liquid materials which can instantly form gels without damaging natural tissue will find many medical applications, such as treatment of arteriovenous malformation (AVM), stopping of bleeding and preparation of bioartificial organs. We prepared various liquid materials and examined their effctiveness using animal models.Arteriovenous malformation : Embolic liquid was prepared by dissolving poly (2-hydroxyethyl methacrylate-co-methyl methacrylate) in Iopamiron with an addition of a small amount of ethyl alcohol. Isostearyl-2-cyanoacrylate was also synthesized for emboliation. These new embolic liquid is not cytotoxic and is easily injected into the AVM through a thin, long catheter to effectively occlude the AVM.Hemostatic agent : The N-hydroxysuccinimide (NHS) activated poly (L-glutamic acid)(PLGA) was synthesized. This NHS activated PLGA could instantly form a gel with gelatin in an aqueous solution. This finding strongly suggest that this combination of gelatin and NHS-PLGA is verypromising as a hemostatic agent and adhesion-prevention agent, and may possibly replace fibrin glues prepared from human blood components.Cell entrapment : The hydrogel was produced from a polyacrylamide derivative carrying thiol groups synthesized by redical copolymerization of acrylamide and N,N'-bis acrylcytamine, followed by reduction of the disulfide bonds in the copolymer. This water-soluble copolymer was used to entrap hamster islets by re-formation of disulfide bonds on the copolymer to produce a hydrogel. Insulin release from the islets in the hydrogel continued for more than 1 month when examined in vitro.