In Vitro Cytotoxicity and Protein Drug Release Properties of Chitosan/Heparin Microspheres

Chitosan/heparin microspheres were prepared using the water-in-oil emulsification solvent evapo- ration technique. The microsphere diameters were controlled by selecting the fabrication process parame- ters. Scanning electron micrographs showed that the chitosan/heparin microspheres were regular and the surface morphology was smooth. Fourier transform infrared showed that the chitosan amino groups reacted with heparin carboxylic groups to form acylamides in the microspheres. Analysis of the microsphere cytotox- icity showed that they had no cytotoxic effect and behaved very similar to the negative control (polystyrene). To analyze the protein drug release profiles of the microspheres, bovine serum albumin was loaded as a model drug into the microspheres and released in vitro. Marked retardation was observed in the BSA re- lease profiles. The results show that chitosan/heparin microspheres may provide a useful controlled release protein drug system for used in pharmaceutics.     

8种有机溶剂对肿瘤细胞的细胞毒作用

实验中常需要有机溶剂溶解水溶性较差的待筛选样品,笔者为抗肿瘤药物体外筛选时选择适宜体积分数下低毒且溶解性能好的有机溶剂作参考.用改良MTT法测试8种常用溶剂对2种人肿瘤细胞株生长的影响.甲醇、乙酸乙酯、乙醇、乙二醇、二甲基亚砜(DMSO)、氯仿、丙酮和正丁醇对人肺癌细胞株A549的IC50分别为3.50,0.61,2.09×10-2,3.79×10-2,4.07×10-3,2.10×10-2,4.04×10-3,2.62×10-4?μg/mL;甲醇、乙酸乙酯、乙二醇、二甲基亚砜、氯仿、丙酮和正丁醇对人肝癌细胞株BeL-7402的IC50分别为0.28,0.89,5.82×10-2,9.67×10-3,5.54×10-2,8.00×10-3,1.61×10-3?μg/mL.结果说明体积分数为0～10%的甲醇和乙酸乙酯细胞毒性甚微,宜选用;乙醇、乙二醇选用低于3%的体积分数;DMSO宜用低于1%的体积分数;丙酮和氯仿宜选择低于0.3%的体积分数;正丁醇的细胞毒性较强,不适合用于筛药中.     

新一代阳离子聚合物转染试剂(梭华-Sofast) 转染效果研究

采用DNA延滞实验研究新一代阳离子聚合物梭华 Sofast转染试剂与DNA的结合能力,以不同报告基因(绿色荧光蛋白基因、β 半乳糖苷酶基因和荧光素酶基因),分析比较梭华 Sofast与阳离子脂质体Lipofectamine2000和阳离子聚合物JetPEI、Superfect转染HEK293细胞转染效率和细胞毒性,研究梭华 Sofast转染试剂转染效率.实验结果表明梭华 Sofast与DNA有很强的结合能力;以绿色荧光蛋白基因为报告基因,梭华 Sofast转染率最高,约60%左右,而且在单个细胞中表达的GFP量多;转染细胞荧光素酶活性检测结果表明,当梭华 Sofast与DNA质量比为16时,转染率最高,高于109RLU/mg蛋白,分别是JetPEI,Superfect和Lipofectamine2000转染细胞最高活性的1.6,2.3和5倍;梭华 Sofast转染β 半乳糖苷酶的染色结果显示95%以上的阳性细胞转染率;比较基因转染效率最高时的细胞毒性,在最佳转染剂量时,几种试剂的细胞存活率均在83%以上,而梭华 Sofast为94.23%.在目前市场上销售的转染试剂对HUV EC细胞的转染效果均不理想情况下,梭华 Sofast仍具一定的转染效率,阳性细胞约占20%.研究结果表明梭华 Sofast是一种高转染效率,低细胞毒性的转染试剂.