The Electric Field in Solid State Nanopores Causes Dissociation of Strong Biomolecular Interactions

Abstract

Electrical sensing with nanopores has become a widely used bioanalytical tool. However, it remains unclear if and how the extremely strong electric field generated inside the pores influences biomolecular interactions. Here we show that the field disrupts the strongest known protein-ligand interaction in biology, namely biotin-avidin bonds. Remarkably, the lifetime of the interaction is decreased by at least 4 orders of magnitude. At hundreds of mV, avidin (from egg-white) starts dissociating from biotin-functionalized nanopores over a time scale of minutes even at the maximum bond valency of four. Streptavidin-coated nanoparticles, which form many more bonds, remain bound but exhibit surface mobility due to the field. These results show that nanopore sensors can give very inaccurate results when used for affinity-based detection or biomolecular interaction analysis and that the pore environment should be regarded as potentially invasive for the molecules inside.