Nanomechanical Control of Cell Rolling in Two Dimensions through Surface Patterning of Receptors

We envisioned that label-free control of the transport of cells in two dimensions through receptor–ligand interactions would enable simple separation systems that are easy to implement yet retain the specificity of receptor–ligand interactions. Here we demonstrate nanomechanical control of cell transport in two dimensions via transient receptor–ligand adhesive bonds by patterning of receptors that direct cell rolling through an edge effect. HL-60 cells rolling on P-selectin receptor patterns were deflected at angles of 5–10° with respect to their direction of travel. Absence of this effect in the case of rigid microsphere models of cell rolling suggests that this two-dimensional motion depends on nanomechanical properties of the rolling cell. This work suggests the feasibility of simple continuous-flow microfluidic cell separation systems that minimize processing steps and yet retain the specificity of receptor–ligand interactions.