Engineering artificial switchable nanochannels for selective monitoring of nitric oxide release from living cells.

Nitric oxide (NO) can delicately tune the cellular signaling pathway and plays crucial roles in physiological processes. It is of profound significance to engineer a smart and efficient artificial platform to detect NO, especially for the tracking of living cell released NO. Herein, a switchable nitric oxide responsive nanochannel analysis platform is constructed by introducing a reversible N-nitrosation reaction of rhodamine 6G (R6G) into the artificial nanochannels. By virtue of the distinctive design, ionic current signal can handily realize reversible switching between "on" and "off" state in the presence of NO and UV light, and the system featured high stability and reproducibility. The R6G-immobilized nanochannels exhibited high sensitivity and selectivity towards NO over other gas molecules and biomolecules by ion current rectification (ICR) test. More intriguingly, the system also showed good performances for in situ monitoring of NO released from human umbilical vein endothelial cells (HUVECs), suggesting the as-constructed nanochannels can act as a versatile NO gas valve for nanoelectronic logic devices. This work purposes a novel method for the rapid and noninvasive detection of bioactive gas and holds great promise for biomedical research, disease diagnosis and treatment.