Light and pH Cooperative Nanofluidic Diode Using a Spiropyran-Functionalized Single Nanochannel

An artificial nanofluidic diode system is prepared (see figure), mimicking the light-gated and pH-tunable ion channels that play an important role in life sciences. When UV light is off, the nanochannel is in the closed state, analogous to a resistance. Under UV light irradiation and at pH 7, the current flows from the tip to the base, analogous to a diode; at pH 3, the situation (and the diode) is reversed.