Protein Concentration And Separation On Micro/Nanofluidic Chips

The development of microfluidic chips has enabled the miniaturization of manybiochemical techniques, resulting in a faster and more accurate analysis capability thanthat provided by traditional devices. Recently, nanostructures have been introduced intomicrofluidic devices with the development of nanofabrication technology, giving rise tothe field of modern nanofluidics. Studies in nanofluidics enable many applicationsincluding biomolecular pretreatment, separation and detection, which provideconsiderable potential for proteomics.In proteomics research, preconcentration of low abundance proteins is a key step inthe detection of complex protein samples. In this work, we developed a micro/nano-fluidic concentration platform based on the exclusion-enrichment effect of nanostructure.We fabricated nanostructure spans across the entire microchannel height inpoly(dimethylsiloxane)(PDMS)-based microchip using cation-permeability Nafion forsmall molecules and proteins preconcentration. With the optimization of concentratingconditions, an about1010fold concentration factor was achieved within30min using0.1fM-level negatively charged fluorescein, FITC-BSA, FITC-IgG. This platform could beuseful for on-line concentration of proteins.We then established a chip concentration&capillary electrophoresis system (CCCE)based the micro/nano-fluidic concentration platform. An interface between chip and CEwas designed in the elastic PDMS layers. The results showed that the chip and capillarycould be successfully connected with no sample leakage. The initial concentration of0.33nM FITC-IgG could be detected by capillary electrophoresis after chip concentrating. Theconcentration factor was up to102. This CCCE has potential for integrating onlineconcentration, separation to mass spectrometry detection.