Prolonged Excursion of a Single Protein into a Synthetic Nanopore

Abstract

Nanopores drilled into silicon nitride were used as stochastic sensors to inspect protein analytes at the single molecule level. Measurements on the protein bovine serum albumin (BSA) revealed both short-lived current spikes, in the range of tens of microsends, and long-lived current blockades, in the range of seconds. The presence of long-lived current blockades suggests a strong interaction between BSA molecules and the nitride surface of the nanopore interior. The nature of these long duration interactions was explored under a variety of conditions. Single-channel current analysis indicated that this interaction does not follow a simple bimolecular kinetic pathway. We hypothesize that BSA enters the nanopore in a non-equilibrium state in order for such interactions to occur.