Solid-State Nanochannel-Based Sensing Systems: Development, Challenges, and Opportunities.

Solid-state nanochannel-based sensing systems with various structures and morphologies have realized precise measurements for various key biomarkers due to their tunable physical structures and morphologies, controllable chemical properties, and a nanoconfined space-induced target enriching effect. In the past several decades, series of solid-state nanochannel-based sensing systems mainly focused on modifying functional elements on nanochannels have allowed for a highly sensitive and specific detection of various key biomarkers between 0.1 and 100 nm, including small molecules, nucleic acids, and proteins. However, traditional solid-state nanochannel-based sensing systems have mainly focused on the functional element modified on their inner-walls (FE IW ), ignoring the ion-gating effect of functional elements modified on the outer surface (FE OS ). Therefore, the direct detection of targets with sizes larger than the diameters of nanochannels, i.e., cells, was hard to realize. Recently, research has turned its attention to nanochannels with FE OS , which extends the range of measurable biomarkers to cells (50 μm) and promotes precise measurements. In this Perspective, we mainly focus on exhibiting the great breakthroughs of solid-state nanochannels with distinct partitions of the inner wall (IW) and outer surface (OS). Meanwhile, the cutting-edge concept of nanochannels with quantum confined superfluid (QSF) is also discussed. A possible explanation for the ultrafast flow of liquids and gases through nanopores based on wave-particle duality was also provided. The quantum effect on ultrafast flow would provide new perspectives for nanochannel-based sensing systems for various key biomarkers, which may also promote the development of seawater desalination, energy conversion, and information systems.