Micropatterned "adherent/repellent" glass surfaces for studying the spreading kinetics of individual red blood cells onto protein-decorated substrates.

We report in this paper two simple and effective methods to decorate glass surfaces that enable protein micropatterning and subsequent spatially controlled adhesion of cells. The first method combines simultaneously the potentialities of two existing techniques, namely microcontact printing (muCP) and microfluidic networks (muFN) to achieve dual protein patterning in a single step. The second method is mainly based on the well-known property of poly(ethylene glycol) (PEG) to resist against protein adsorption. Both approaches were used to produce heterogeneous surfaces on which micron-size or submicronic streptavidin-coated lines alternate with cell-repellent areas. We first describe the implementation of the two methods and discuss the main pitfalls to avoid. Then, using these templates, we have monitored the kinetics of attachment of individual biotinylated (i.e. "attractant" towards streptavidin) red blood cells by directly measuring the propagation velocity of the adhesion front. Depending on the surface density of biotin, we found two distinct regimes, in agreement with existing theoretical models.