Flavone-Based ESIPT Ratiometric Chemodosimeter for Detection of Cysteine in Living Cells

Abstract

We have designed and synthesized a novel ratiometric fluorescent chemodosimeter <b>MHF</b>-based ESIPT process for specific detection of cysteine among the biological thiols. The probe <b>MHF</b> shows very weak blue fluorescence under UV excitation. Upon addition of cysteine (Cys), the reaction of Cys with <b>MHF</b> induces acrylate hydrolysis, thereby enabling the ESIPT process to shift the weak blue emission to a strong green emission with about 20-fold enhancement. We utilized ¹H NMR spectra to elucidate the fluorescence sensing mechanism. Moreover, the cellular imaging experiment indicated the <b>MHF</b> possessed excellent selectivity, low cytotoxicity, and desirable cell permeability for biological applications