Archaea-Inspired Switchable Nanochannels for On-Demand Lithium Detection by pH Activation.

With the rapid development of the lithium ion battery industry, emerging lithium (Li) enrichment in nature has attracted ever-growing attention due to the biotoxicity of high Li levels. To date, fast lithium ion (Li) detection remains urgent but is limited by the selectivity, sensitivity, and stability of conventional technologies based on passive response processes. In nature, archaeal plasma membrane ion exchangers (NCLX_Mj) exhibit Li-gated multi/monovalent ion transport behavior, activated by different stimuli. Inspired by NCLX_Mj, we design a pH-controlled biomimetic Li-responsive solid-state nanochannel system for on-demand Li detection using 2-(2-hydroxyphenyl)benzoxazole (HPBO) units as Li recognition groups. Pristine HPBO is not reactive to Li, whereas negatively charged HPBO enables specific Li coordination under alkaline conditions to decrease the ion exchange capacity of nanochannels. On-demand Li detection is achieved by monitoring the decline in currents, thereby ensuring precise and stable Li recognition (>0.1 mM) in the toxic range of Li concentration (>1.5 mM) for human beings. This work provides a new approach to constructing Li detection nanodevices and has potential for applications of Li-related industries and medical services.