On-site discrimination of biothiols in biological fluids by a novel fluorescent probe and a portable fluorescence detection device

On-site discrimination of the most abundant low-molecular-weight biothiols including Cys, CysGly, Hcy and GSH in biological fluid is extremely valuable for diagnosing and dissecting various diseases. However, this remains a great challenge due to the very similar structure and reactive activity of the four biothiols. Herein, a novel fluorescent probe that is able to concurrently discriminate Cys, CysGly, Hcy and GSH in distinct fluorescence channel based on a new strategy of regulating the nucleophilic ability of amine group in Cys, CysGly, Hcy and GSH under distinct pH condition. Moreover, a portable fluorescence detection device that can on-site accurately quantify the fluorescence intensities in biological fluid has been rationally fabricated. The fluorescent probe in combination with the self-made portable fluorescence detection device has been successfully applied for on-site quantitative discrimination of Cys, CysGly, Hcy and GSH in biological fluids such as plasma and urine, which provides a quick and inexpensive way to screen and diagnose the biothiols related diseases as well as dissect their physiological and pathological processes.