Patterning protein concentration using laser-assisted adsorption by photobleaching, LAPAP.

The study of cellular responses to changes in the spatial distribution of molecules in development, immunology and cancer, requires reliable methods to reproduce in vitro the precise distributions of proteins found in vivo. Here we present a straightforward method for generating substrate-bound protein patterns which has the simplicity required to be implemented in typical life science laboratories. The method exploits photobleaching of fluorescently tagged molecules to generate patterns and concentration gradients of protein with sub-micron spatial resolution. We provide an extensive characterization of the technique and demonstrate, as proof of principle, axon guidance by gradients of substrate-bound laminin peptide generated in vitro using LAPAP.