LAUSR

In this work, biomass-derived carbon quantum dots (CQDs) with excellent water solubility, strong fluorescence and favorable biocompatibility were synthesized via one-step hydrothermal treatment of purple perilla for the first time. The functional group composition, morphology, and pH stability of the synthesized CQDs were systematically investigated. And based on fluorescence quenching of CQDs, the as-prepared CQDs were innovatively developed as an effective "signal-off" fluorescent probe for selective and sensitive detection of silver ion (Ag+) with two linear ranges of 0-10 and 10-3000 nM, and a detection limit 1.4 nM. The specificity and selectivity of this fluorescent probe were also verified through challenging the detection by using similarmetallic cations or in real water samples. In addition, the as-prepared CQDs exhibit a low cytotoxicity and a good biocompatibility, revealing its potential bioimaging applications in living cells.