A molecular design towards sulfonyl aza-BODIPY based NIR fluorescent and colorimetric probe for selective cysteine detection

Abstract

Cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) are essential biothiols for cellular growth, metabolism, and maintenance of a biological system. Thus, the detection of biothiols is highly important for early diagnosis and evaluation of disease progression. In this article, a series of sulfonyl aza-BODIPYs was synthesized, characterized, and examined by1H-NMR,13C-NMR, crystallization, photophysical properties and DFT calculation. Among these structures, a fluorescent probe,BDP-1, exhibited selective detection of Cys among various biothiolsvianucleophilic aromatic substitution and typical size of Cys molecules.BDP-1showed color change and near-infrared (NIR) fluorescence enhancement after reaction with Cys to generateBDP-OH, confirmed by HRMS. The red shift of absorption wavelength showed a similar tendency resulting in time-dependent density functional theory (TD-DFT). Furthermore, the calculated detection limit ofBDP-1toward Cys was 5.23 μM. This probe facilitates the colorimetric and fluorescent detection of Cys over other biothiols.