Enriching carbonylated proteins inside a microchip through the use of oxalyldihydrazide as a crosslinker.

We report a proof of principle study for the use of oxalyldihydrazide as a crosslinker for enrichment of carbonylated proteins within a microfluidic chip. Surface modification steps are characterized and analyzed using analytical techniques. We use oxidized cytochrome c as our model protein and demonstrate the chip's ability to capture carbonylated targets. After 100 min of continuous loading, the chip is capable of capturing 7.5 μg of carbonylated protein. All the proteins captured are eluted out of the chip using the elution protocol. Finally, we demonstrate the chip's specificity for oxidized targets by mixing oxidized cytochrome c and TRITC-BSA, with cytochrome c in low abundance. The results show that the chip is efficient at finding its target when unoxidized proteins are present. This is the first report to suggest the use of immobilized oxalyldihydrazide on a microchip as an enrichment methodology for low abundance proteins in a sample.