A highly sensitive and selective artificial nanochannel for in situ detection of hydroxyl radicals in single living cell.

As the most aggressive reactive oxygen species (ROS), hydroxyl radical (•OH) can directly modulate the biological ion channel and interfere with the progression of diseases. Inspired by biological •OH-activated ion channel, we reported a novel •OH-regulated glass nanopore functionalized with protoporphyrin Ⅸ (PP) film. This system showed outstanding •OH selective response owing to the ultra-fast reaction between •OH and thiol derivatives. In this case, the PP film is responsible for the changing not only of wettability but also of the inner surface charge. The synergetic effect of the dual transitions can regulate the ion transportation within the nanochannels and enabled tremendous enhancement of responsive efficiency. The detection limit could be achieved down to 1.58 nM. Taking advantage of the excellent analytical performance and mechanical qualities of this glass nanopore, the changes of •OH in single living cells were in situ monitored. Together, this study is beneficial for exploring the role of •OH in pathological events and shows promising potential for biomedical research.