A highly selective and recyclable NO-responsive nanochannel based on a spiroring opening−closing reaction strategy

Endogenous nitric oxide (NO) is an important messenger molecule, which can directly activate K(+) transmission and cause relaxation of vascular smooth muscle. Here, inspired by the K(+) channel of smooth muscle cells, we report, a novel NO-regulated artificial nanochannel based on a spiro ring opening−closing reaction strategy. This nanofluidic diode system shows an outstanding NO selective response owing to the specific reaction between o-phenylenediamine (OPD) and NO on the channel surface with high ion rectification ratio (~6.7) and ion gating ratio (~4). Moreover, this NO gating system exhibits excellent reversibility and stability as well as high selectivity response. This system not only helps us understand the process of NO directly regulating biological ion channels, but also has potential application value in the field of biosensors.