Probing surface hydrophobicity of individual protein at single-molecule resolution using solid-state nanopores

Solid-state nanopore is found to be a promising tool to detect proteins and their complexes. Nanopore-protein interaction is a fundamental and ubiquitous process in biology and medical biotechnology. By translocating phi29 connector protein through silicon nitride nanopores, we demonstrate preliminarily probing the surface hydrophobicity of individual protein at single-molecule resolution. The unique “double-level event” observed in the translocation and the ratio of two current drop levels suggest that the position where the interaction occurs is the hydrophobic surface of the protein. We provide a potential method to locate the hydrophobic region of a specific protein surface. This study is of fundamental significance in revealing the important role that hydrophobic interaction plays in nanopore-protein interaction and holds great potential for detecting local surface chemical property of individual protein using solid-state nanopores.