Shape characterization and discrimination of single nanoparticles using solid-state nanopores†
Resistive pulse sensing with nanopores is expected to enable identification and analysis of nanoscale objects in ionic solutions. However, there is currently no remarkable method to characterize the three-dimensional shape of charged biomolecules or nanoparticles with low-cost and high-throughput. Here we demonstrate the sensing capability of solid-state nanopores for shape characterization of single nanoparticles by monitoring the ionic current blockades during their electrophoretic translocation through nanopores. By using nanopores that are a bit larger than the particles, shape characterization of both spherical and cubic silver nanoparticles is successfully realized due to their rapid rotation with respect to the pore axis, which is further validated by our all-atom molecular dynamics simulations. The single-molecule approach based on nanopores will allow people to measure the dimension and to characterize the shape of single nanoparticles or proteins simultaneously in real time, which is significant for its potential application in investigation of structural biology and proteomics in the near future.