Wong Ven Ney, Fernando Ganga, Wagner Audrey R, Zhang Jianming, Kinsel Gary R, Zauscher Stefan, Dyer Daniel J
Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois 62901-4409, USA.
Langmuir. 2009 Feb 3;25(3):1459-65. doi: 10.1021/la802723r.
A polymer brush consisting of 70% poly(N-isopropylacrylamide) (PNIPAAM) and 30% polymethacrylic acid (PMAA) was synthesized from gold substrates with a "grafting from" AIBN-type free-radical initiator. Fractionation of two peptides, bradykinin and buccalin, was accomplished in less than 120 s by placing a 30 pM (pH approximately 6.2) droplet onto the polymer brush substrate. The eluant containing the anionic buccalin is pipetted away for MALDI analysis while the cationic bradykinin adsorbed to the swollen anionic brush and was subsequently released by adding a droplet of formic acid to the substrate. This caused the brush to collapse and release the bradykinin, much like squeezing a sponge; these nanosponge substrates exhibited very high loading capacity (>2.0 mg/mL) compared to plasma-polymer-modified MALDI substrates. Ellipsometric measurements showed that complementary peptides adsorb rapidly while those of the same charge do not, and MALDI-MS analysis of the two fractions showed separation of both peptides. The adsorption of bradykinin was monitored over time, and 85% of the peptide had been adsorbed to the nanosponge in 1 min from a 0.5 mg/mL aqueous solution.
一种由70%聚（N - 异丙基丙烯酰胺）（PNIPAAM）和30%聚甲基丙烯酸（PMAA）组成的聚合物刷，通过“从……接枝”AIBN型自由基引发剂从金基底上合成。通过将一滴30 pM（pH约为6.2）的溶液滴到聚合物刷基底上，在不到120秒的时间内完成了两种肽（缓激肽和蟾蜍铃肽）的分离。含有阴离子蟾蜍铃肽的洗脱液被吸移用于基质辅助激光解吸电离（MALDI）分析，而阳离子缓激肽吸附到溶胀的阴离子刷上，随后通过向基底添加一滴甲酸将其释放。这导致刷子塌陷并释放缓激肽，就像挤压海绵一样；与等离子体聚合物修饰的MALDI基底相比，这些纳米海绵基底表现出非常高的负载能力（>2.0 mg/mL）。椭偏测量表明，互补肽快速吸附，而相同电荷的肽则不会，对这两个馏分的MALDI - 质谱分析显示两种肽都被分离。监测缓激肽随时间的吸附情况，在1分钟内，85%的肽从0.5 mg/mL的水溶液中吸附到纳米海绵上。
