Cell chip array for microfluidic proteomics enabling rapid in situ assessment of intracellular protein phosphorylation.

We discuss the ability to perform fluorescent immunocytochemistry, following cell fixation, using a microfluidic array of primary, nonadherent, single CD34+ stem cells. The technique requires small cell samples and proceeds with no cell loss, making it well-suited to monitoring these rare patient-derived cells. The chip allows us to correlate live cell dynamics across arrays of individual cells with post-translational modifications of intracellular proteins, following their exposure to drug treatments. Results also show that due to the microfluidic environment, the time scale of cell fixation was significantly reduced compared to conventional methods, leading to greater confidence in the status of the protein modifications studied.