ESIPT triggered swift determination of cysteine in HeLa cell line during redox imbalance

Detection of cysteine is crucial as its deviation from normal concentration leads to various diseases. In this work, benzothiazole based chemodosimeter was synthesized to discriminate cysteine rapidly in the presence of other competing interferences. The probe exhibit ESIPT governed colorimetric and fluoremetric response on addition of cysteine via conjugate addition-cyclization reaction and it is confirmed by NMR and HRMS. The probe can detect lower concentration of cysteine with limit of detection 0.07 mu M in 2 min that assist the system to work well in biological systems. Hence the sensor was profitably employed in imaging of cysteine in HeLa cell line and variance in the redox state was also investigated.