Biphenyl-based AIE-active turn-on fluorescent probes for simultaneous sensing of biothiols and amine vapors and visual real-time monitoring of seafood spoilage

Abnormal level of biothiols content in living organisms and volatile vapor amines could cause severe injury to human health, development of convenient and portable detecting devices for the biothiols and amines recog-nition is bound to scientific significance as well as practical application. Up to now, mainly confined by ag-gregation caused quenching (ACQ) effect, the potential application of traditional fluorescent sensing were extremely restricted. In this contribution, two biphenyl-based "turn-on" type fluorescent probes FCH-NBSC and FCH-AC were designed and constructed for biothiols and vapor amines quantitative detection respectively, which were consisted of a common fluorophore FCH-OH with AIE properties and two sensitive recognition segments nitrobenzene sulfonyl chloride (NBSC) and acetyl (AC). Date from experiments demonstrated that probe FCH-NBSC and FCH-AC exhibited excellent linearity and low detection limits for detection of biothiols (Cys, 0.228 mu M, GSH, 0.212 mu M, Hcy, 0.315 mu M, vapor amine, 7.6 ppm), respectively. Sensing mechanism demonstrated that this fluorescent characteristics variation could be ascribed to biothiols and vapor amines caused cleavage of NBSC segment of FCH-NBSC and AC group of FCH-AC respectively to form a common ESIPT compound FCH-OH, which opened aggregation induced emission (AIE) property promoted by intra/intermo-lecular H-bonds. Furthermore, FCH-NBSC can successfully achieve rapid biothiols recognition inside biological cells via difference in fluorescent signals due to its low toxicity and high sensitivity. Meanwhile, probe FCH-AC have been applied in visual real-time monitoring of seafood spoilage field due to its unique recognition effect for amine vapor.