Single Molecule Measurements of Small Molecule Interactions with Metallic Nanoclusters

Abstract

We report a new technique to characterize metallic nanoclusters using single molecule nanopore measurements for biosensing applications. These measurements allowed the characterization of the structure of polyoxometalate (POM) clusters at micromolar solution concentrations. Interestingly, POMs can be altered with the proton concentration in solution, allowing precise control of structure and charge. Structural changes in the POMs as a function of pH were recorded with nanopores and validated independently with NMR measurements. Furthermore, because of their nucleophilic character, POMs are highly reactive and interact electrostatically with cationic small molecules in solution. We measured these interactions using nanopore measurements and demonstrate the use of POMs as versatile substrates for detecting and characterizing biologically relevant small molecules.