Fundamentals and potentials of solid-state nanopores: a review

Solid-state nanopore (SSNP) technology presents an emerging single-molecule based analytical tool for separation and analysis of biomolecules or nanoparticles. Different prominent approaches have been pursued to attain the anticipated detection performance: process innovation to achieve pore size matching the physical dimensions of biomolecules so as to boost signal; electrolyte management to control translocation speed so as to improve signal quality; surface functionalisation to amplify molecular differences so as to enhance specificity; and implementation of additional, complementary means, such as optical, to manipulate the translocation so as to increase data fidelity. This review focuses on the fundamentals pertaining to the physical processes involved in nanopore sensing based on SSNPs of distinct shapes. It also provides a comprehensive picture regarding challenges and development trends in putting nanopore-based molecular sensors in use. This effort is facilitated by establishing physical-phenomenological models supported by experiment and numerical simulation. To assist the readership, the discussion starts from relatively simple cases and then develops towards complex systems, i.e. from open-pore state to analyte translocation and from single pores to pore arrays. Key physical parameter threading through these aspects is effective transport length that is simple to perceive and easy to calculate. (topical review)