Construction of fluorescent logic gates for the detection of mercury(II) and ciprofloxacin based on phycocyanin.

Chemical pollutants such as heavy metals and antibiotics in the environment pose a huge threat to humans and animals. Our studies have demonstrated that the fluorescence of phycocyanin showed quenching responses towards both mercury (Hg2+) and ciprofloxacin (CIP), which acted in accordance with the 'OR' molecular logic gate. In order to discriminate Hg2+and CIP in application scenarios, cysteine (Cys) was utilized to design another 'INHIBIT' logic gate, in which Hg2+and Cys were the two inputs. Thus, an intelligent biosensor with dual-target identification capacity was successfully developed by using a fluorescent natural protein in an ingenious logic gate system.