Tunable Membranes for Free-Flow Zone Electrophoresis in PDMS Microchip Using Guided Self-Assembly of Silica Microbeads

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• 作者：Yong-Ak Song ; Lidan Wu ; Steven R. Tannenbaum ; John S. Wishnok ; Jongyoon Han
• 刊名：Analytical Chemistry
• 出版年：2013
• 出版时间：December 17, 2013
• 年：2013
• 卷：85
• 期：24
• 页码：11695-11699
• 全文大小：318K
• 年卷期：v.85,no.24(December 17, 2013)
• ISSN：1520-6882

文摘

In this paper, we evaluate the strategy of using self-assembled microbeads to build a robust and tunable membrane for free-flow zone electrophoresis in a PDMS microfluidic chip. To fabricate a porous membrane as a salt bridge for free-flow zone electrophoresis, we used silica or polystyrene microbeads between 3鈥? 渭m in diameter and packed them inside a microchannel. After complete evaporation, we infiltrated the porous microbead structure with a positively or negatively charged hydrogel to modify its surface charge polarity. Using this device, we demonstrated binary sorting (separation of positive and negative species at a given pH) of peptides and dyes in standard buffer systems without using sheath flows. The sample loss during sorting could be minimized by using ion selectivity of hydrogel-infiltrated microbead membranes. Our fabrication method enables building a robust membrane for pressure-driven free-flow zone electrophoresis with tunable pore size as well as surface charge polarity.