Xiao Deqing, Le Thai Van, Wirth Mary J
Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
Anal Chem. 2004 Apr 1;76(7):2055-61. doi: 10.1021/ac035254s.
The electrophoresis of proteins was investigated using poly(dimethylsiloxane) (PDMS) microfluidic chips whose surfaces were modified with polyacrylamide through atom-transfer radical polymerization. PDMS microchips were made using a glass replica to mold channels 10 microm high and 30 microm wide, with a T-intersection. The surface modification of the channels involved surface oxidation, followed by the formation of a self-assembled monolayer of benzyl chloride initiators, and then atom-transfer radical polymerization to grow a thin layer of covalently bonded polyacrylamide. The channels filled spontaneously with aqueous buffer due to the hydrophilicity of the coating. The resistance to protein adsorption was studied by open-channel electrophoresis for bovine serum albumin labeled with fluorophor. A plate height of 30 microm, corresponding to an efficiency of 33 000 plates/m, was obtained for field strengths from 18 to 889 V/cm. The lack of dependence of plate height on field strength indicates that there is no detectable contribution to broadening from adsorption. A 2- to 3-fold larger plate height was obtained for electrophoresis in a 50-cm polyacrylamide-coated silica capillary, and the shape of the electropherogram indicated the efficiency is limited by a distribution of species. The commercial capillary exhibited both reversible and irreversible adsorption of protein, whereas the PDMS microchip exhibited neither. A separation of lysozyme and cytochrome c in 35 s was demonstrated for the PDMS microchip.
使用通过原子转移自由基聚合用聚丙烯酰胺修饰表面的聚二甲基硅氧烷（PDMS）微流控芯片研究了蛋白质的电泳。PDMS微芯片是使用玻璃复制品制作的，用于模制高10微米、宽30微米且带有T形交叉点的通道。通道的表面改性包括表面氧化，随后形成苄基氯引发剂的自组装单分子层，然后进行原子转移自由基聚合以生长共价键合的聚丙烯酰胺薄层。由于涂层的亲水性，通道会自发充满水性缓冲液。通过对用荧光团标记的牛血清白蛋白进行开通道电泳研究了对蛋白质吸附的抗性。对于18至889 V/cm的场强，获得了30微米的板高，对应于33000板/米的效率。板高与场强无关表明没有可检测到的吸附加宽贡献。在50厘米的聚丙烯酰胺涂层硅胶毛细管中进行电泳时，板高会增大2至3倍，并且电泳图谱的形状表明效率受物种分布的限制。商用毛细管表现出蛋白质的可逆和不可逆吸附，而PDMS微芯片则均未表现出。PDMS微芯片在35秒内实现了溶菌酶和细胞色素c的分离。
