Established methods for characterizing proteins typically require physical or chemical modification steps or cannot be used to examine individual molecules in solution. Ionic current measurements through electrolyte-filled nanopores can characterize single native proteins in an aqueous environment, but currently offer only limited capabilities. Here we show that the zeptolitre sensing volume of bilayer-coated solid-state nanopores can be used to determine the approximate shape, volume, charge, rotational diffusion coefficient and dipole moment of individual proteins. To do this, we developed a theory for the quantitative understanding of modulations in ionic current that arise from the rotational dynamics of single proteins as they move through the electric field inside the nanopore. The approach allows us to measure the five parameters simultaneously, and we show that they can be used to identify, characterize and quantify proteins and protein complexes with potential implications for structural biology, proteomics, biomarker detection and routine protein analysis.

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Slowing down to improve nanopore measurements (2019)

Synthetic nanopores are a promising method for characterizing individual molecules such as proteins, but interactions between the pore and the molecules being studied often interfere with the outcome. Researchers from Professor Michael Mayer’s Biophysics group have sought inspiration from nature to make the process more efficient and precise, ultimately yielding more accurate measurements.