nanochannel

Nanochannel is a fluidic channel whose characteristic dimensions transverse to flow are on the nanometer scale, typically from 1 to a few hundred nanometers. In nanochannels, fluid and ionic transport are strongly influenced by surface interactions, confinement effects, and electrokinetic phenomena, enabling discrimination at the single-molecule level.

Nanochannels are realized in solid-state materials such as silicon, silicon nitride, quartz, and glass by top-down fabrication, or in 2D materials like graphene, as well as in biological contexts via protein-based channels. Fabrication methods include electron-beam lithography, reactive ion etching, focused ion beam milling, and nanoimprint lithography; bottom-up approaches include assembly of nanoscale pores in membranes and carbon nanotube channels.

Because dimensions are comparable to molecular sizes, the transport of ions and biomolecules is highly sensitive to surface charge, electrolyte composition, and applied electric fields. Phenomena include ionic current rectification, electro-osmotic flow, and enhanced molecular confinement, which can permit detection and analysis of single molecules as they pass through or are trapped in the channel.

Applications of nanochannels include lab-on-a-chip devices for DNA analysis, single-molecule sensing, sequencing, selective transport studies, filtration, and desalination research. The field of nanochannels intersects nanofluidics, materials science, and biophysics, supporting both fundamental studies and practical sensing and separation technologies.