An ‘OFF–ON’ fluorescent probe for specially recognize on Cys and its application in bioimaging

Dyes derived from benzo[a]phenoxazine – synthesis, spectroscopic properties, and potential application as sensors for l‐cysteine

“…Table 2 shows the detection limits of the tested compounds 7a to 7c for L-Cys. The lowest concentration of L-Cys that can be determined by the presented fluorescent probes is 0.111-0.271 lM, which is comparable with other reported compounds [23,26,27,[38][39][40][41][42]. The lowest concentration of L-Cys that can be determined by the presented fluorescent probes is 0.111-0.271 lM, which is comparable with other reported compounds [23,26,27,[38][39][40][41][42].…”

“…The optical detection of thiols is based on specific reactions between probes and sulphydryl derivatives. Since then, a large number of probes with a maleimide moiety have been developed [23][24][25][26][27][28][29][30][31]. In our previous papers [20,21], the synthesis and spectroscopic characterisation, in the presence of various amino acids, of dyes derived from 3formyl-2(1H)-quinolone with different moieties acting as a Michael acceptor were reported.…”

An off-on fluorescent probe for specifically detecting cysteine and its application in bioimaging

“…Moreover, probes that rely on fluorescence quenching suffer from inherent drawbacks including low signal-to-noise ratio and nonspecific quenching [18], so that "turn-on" type fluorescence probes are preferred [19][20][21]. Up to date, and only a few probes are able to discriminate between Cys, Hcy, and GSH [22][23][24][25]. The design of highly selective probes for Cys, Hcy, and GSH is still a challenge.…”

Thiol-chromene click chemistry: A turn-on fluorescent probe for specific detection of cysteine and its application in bioimaging

“…Actually, the tripeptide M a n u s c r i p t 4 structure of GSH induced significant steric shielding which reduced the nucleophilic reactivity of SH group in GSH. Furthermore, the relatively acidic (lower pKa value for the sulfhydryl group compared to other thiols) SH proton of Cys in aqueous media caused higher thiolate/thiol ratio for Cys at neutral pH than it is for most other biologically important thiols, including Hcy and GSH [24,25]. As a consequence, Cys displayed higher nucleophilic reactivity compared with Hcy and GSH under physiological condition which provided new thought for Cys detection.…”