Figure 1.

In situ single-cell western blot (in situ scWB) measures protein expression in single, adherent cells in culture by integrating on-chip 2D cell culture and single-cell western blotting. a) Schematic of the in situ scWB assay for measuring osmotic stress-induced protein phosphorylation. Left: Photographs of an in situ scWB device fabricated on a standard glass microscope slide. The bottom photograph is the zoom-in of the yellow box in the top photograph. The gel on the device was stained blue for visualization. Middle: Workflow of the in situ scWB assay illustrated with one microwell from among an array of ~2000 microwells on the device. Right: A representative false-colored fluorescence micrograph from in situ scWB of stress-induced phosphorylation, and the fluorescence profile along the electrophoretic separation. β-tubulin: 50 kDa. p38: 41 kDa. b) One-step fabrication of the in situ scWB device, composed of arrays of fibronectin-functionalized microwells stippled in a thin layer of polyacrylamide (PA) gel.