Fig. 1.

Design and operation of the microfluidic LAVAgel assay for high-specificity protein isoform analysis. (A) Glass microfluidic device with microchannels linking two fluid reservoirs (dye added for clarity). (Scale bar: 2 mm.) (B) The 80-min five-stage immunoprobing assay is completed in a single microchannel. (C) Schematic of microchannel cross-section depicting principle of the LAVAgel: Analytes are electrophoresed through the reactive nanoporous hydrogel, exposed to UV, and covalently immobilized. (Scale bar: 5 μm.) (D) Schematic of reaction between polypeptide backbone and pendant LAVAgel benzophenone groups. Ph denotes phenyl group. For clarity, the electrophilic triplet state of benzophenone, hydrogen abstraction, and radical intermediates are omitted.