Editorial – From nanopores to nanochannels

Nanofluidics and nanopores, ranging in size from a few hundred nanometers down to subnanometer scales, have recently found a broad range of applications which include DNA sequence analysis, single-molecule spectroscopy, nanoplasmonics, and optical trapping amongst others. With recent advances in nanofabrication, the resolution, throughput, and reproducibility to engineer nanometric pores and channels have improved greatly. This themed issue of Analyst brings together analytical advances related to nanofluidics and nanopores. Making up this issue are 19 articles covering optical spectroscopy, transport through nanopores, translocation behavior, and the ever-growing use of nanopipettes.

For example, following the discovery of the extraordinary optical transmission effect through subwavelength metallic hole arrays, researchers have extensively studied the optical properties of metallic nanoholes for sensing and spectroscopy applications. Dahlin's review article (c4an02258k) provides a perspective on plasmonic sensing applications of metallic nanopores. Subwavelength metallic nanopores have also shown promising results for optical trapping of biological molecules. The review article by Gordon et al. (c4an02213k) summarizes recent developments in nanopore-based optical tweezers for studying protein interactions and techniques to integrate such traps with microfluidics and optical fibers. Masson et al. (c4an02257b) used nanopores patterned in metal films for metal-enhanced fluorescence spectroscopy of molecules.

Furthermore, Siwy et al. (c4an02244k) investigated the transport properties of hydrophobic track-etched nanopores and showed how to regulate the switching between conducting and non-conducting states via the electrolyte concentration. Kim et al. (c5an00250h) produced 250 nm nanopores in a silicon nitride membrane and investigated the membrane deformation of lipid vesicles during translocation subjected to high electric field strengths inside the nanopores.

Aside from conventional solid-state nanopores, nanopipettes have emerged as a versatile platform for nanopore-based sensing. Edel et al. (c5an01001b) show fine tuning of the pore size using atomic layer deposition, and Baker et al. (c4an01073f) investigate the influence of surface charge on nanopipette delivery.

We would like to acknowledge and thank all the contributors for their submissions, which made this themed issue possible. Moreover, we would like to thank the staff at the Royal Society of Chemistry for helping us with the administrative aspects and for coordinating the refereeing process.

To the readers, we hope you find this themed issue a valuable source of information and insight into the field.

Joshua Edel, Imperial College London, UK

Sang-Hyun Oh, University of Minnesota, USA

This journal is © The Royal Society of Chemistry 2015