Superselective colloid-surface binding via multivalent interactions

Directed drug delivery is crucial for targeting cells selectively based on their receptor profile on the surface. Theoretical work by Martinez-Veracoechea et. al. [1] suggests that multivalent probes can distinguish between different surfaces based on the composition of receptors and ligands, also known as superselectivity. We test these predictions experimentally with a model system consisting of colloidal particles and a flat surface, both functionalized with mobile DNA linkers, as the ligand/receptor system [2,3]. With increasing ligand/receptor concentration we observe the formation of a binding patch and a rise in the number of bound particles. The transition between unbound and bound particles depends strongly on the interaction strength of individual ligand-receptor interactions. By introducing very weak interactions, we can tune the system such that we have an almost “on-off” binding behavior. To conclude we show that weak interactions in a model ligand-receptor system lead to superselective particle binding. Our findings will contribute to the design of directed drug delivery systems.

[1] F. J. Martinez-Veracoechea and D. Frenkel, PNAS, 108 (2011)
[2] S. A. J van der Meulen and M. E. Leunissen, JACS, 135 (2013)
[3] I. Chakraborty et al. Nanoscale, 9 (2017)