Cellular self-organization on micro-structured surfaces

Micro-patterned surfaces are frequently used in high-throughput
single-cell studies, as they allow one to image isolated cells in
defined geometries. Commonly, cells are seeded in excess onto the
entire chip, and non-adherent cells are removed from the
unpatterned sectors by rinsing. Here, we report on the phenomenon
of cellular self-organization, which allows for autonomous
positioning of cells on micro-patterned surfaces over time. We
prepared substrates with a regular lattice of protein-coated
adhesion sites surrounded by PLL-g-PEG passivated areas, and
studied the time course of cell ordering. After seeding, cells
randomly migrate over the passivated surface until they find and
permanently attach to adhesion sites. Efficient cellular
self-organization was observed for three commonly used cell lines
(HuH7, A549, and MDA-MB-436), with occupancy levels typically
reaching 40-60% after 3-5 h. The time required for sorting was
found to increase with increasing distance between adhesion sites,
and is well described by the time-to-capture in a random-search
model. Our approach thus paves the way for automated filling of
cell arrays, enabling high-throughput single-cell analysis of cell
samples without losses.