双子表面活性剂及其保护的纳米金作为缓冲添加剂用于毛细管电泳蛋白质分离

Separation of acidic and basic proteins by capillary electrophoresis using gemini surfactants and gemini-capped nanoparticles as buffer additives

报道了使用阳离子双子表面活性剂作为毛细管电泳的缓冲添加剂用于同时分离酸性和碱性蛋白质.在酸性的缓冲条件下,只需要使用低浓度的阳离子双子表面活性剂(0.1mmol/L18-s-18)作为缓冲液的添加剂,就可以有效地抑制酸性和碱性蛋白质在毛细管壁的吸附,从而得到高效的蛋白质分离.实验表明,较小的胶束尺寸(如s=5～8)比大的胶束尺寸(如s<4或>10)能更有效地抑制酸性蛋白质的吸附.改变双子表面活性剂的中间基的长度能够对蛋白质的电泳淌度进行一定的调节,从而对分离的选择性进行一定的优化.在最优的实验条件下,蛋白质迁移时间的日内和日间标准偏差(RSD)分别小于0.8%和2.2%,回收率为79%到100.4%.另外,还考察了双子表面活性剂保护的金纳米颗粒用作毛细管电泳缓冲添加剂在蛋白质分离中的应用.实验表明,在缓冲液中加入纳米金能够缩短分析时间,并能小幅度地提高分离效率.最后,使用该方法分析了一系列复杂生物样品,包括血浆、红细胞和鸡蛋清样品,均得到了满意的结果.

This paper demonstrated simultaneous separation of acidic and basic proteins using cationic gemini surfactants as buffer additives in capillary electrophoresis. We show that even at a low concentration （0.1 mmol/L） of alkanediyl-α, ω-bis（dimethyloctadecylammonium bromide） （18-s-18）, the wall adsorption of both acidic and basic proteins could be effectively suppressed under acidic conditions. Smaller micelle size （e.g., s = 5-8） is more effective for the separation of acidic proteins than larger micelle size （e.g., s 〈4 or〉 10）. Varying the spacer length of gemini surfactants can influence the electrophoretic mobility and selectivity of proteins to achieve the desired separation. Under the optimized conditions, RSDs of migration time were less than 0.8% and 2.2% for run-to-run and day-to-day assays, respectively, and protein recoveries ranged from 79% to 100.4%. Furthermore, we also investigate the use of gemini surfactant-capped gold nanoparticles （gemini@AuNPs） as buffer additives in protein separation. Introduction of AuNPs into the buffer shortened the analysis time and slightly improved the separation efficiencies. Finally, we present the applications of this method in the analysis of biological samples, including plasma, red blood cells, and egg white.