Rapid multicomponent optical protein patterning

Cells sense spatial distributions of molecules which trigger signal transduction pathways that induce the cell to migrate or extend by remodelling the cytoskeleton. However, the influence of local and small variations of extracellular protein concentration on chemotaxis is not fully understood, due in part to the lack of simple and precise methods to pattern proteins in vitro. We recently developed a new technology to fabricate such patterns which relies on photobleaching fluorophores to adsorb proteins on a cell culture substrate: laser-assisted protein adsorption by photobleaching (LAPAP). Here we report several key improvements to LAPAP: we created arbitrary patterns made of several different proteins simultaneously, we reduced the fabrication time more than one order of magnitude and we used secondary antibodies to significantly enlarge the spectrum of proteins that can be employed. As a result, multicomponent protein gradients can be produced using reagents that are typically available in life science research laboratories on a standard inverted microscope equipped with a camera port.