A Near-Infrared Fluorescent and Photoacoustic Probe for Visualizing Biothiols Dynamics in Tumor and Liver

Biothiols, including glutathione (GSH), homocysteine (Hcy) and cysteine (Cys), play crucial roles in various physiological processes. Though an array of fluorescent probes have been designed to visualize biothiols in living organisms, few one-for-all imaging agents for sensing biothiols with fluorescence and photoacoustic imaging capabilities have been reported, since instructions for synchronously enabling and balancing every optical imaging efficacy are deficient. Herein, a new near-infrared thioxanthene-hemicyanine dye (Cy-DNBS) has been constructed for fluorescence and photoacoustic imaging of biothiols in vitro and in vivo. Upon treatment with biothiols, the absorption peak of Cy-DNBS shifted from 592 nm to 726 nm, resulting in a strong NIR absorption as well as a subsequent turn-on PA signal. Meanwhile, the fluorescence intensity increased instantaneously at 762 nm. Then, Cy-DNBS was successfully utilized for imaging endogenous and exogenous biothiols in HepG2 cells and mice. In particular, Cy-DNBS was employed for tracking biothiols upregulation in the liver of mice triggered by S-adenosyl methionine by means of fluorescent and photoacoustic imaging methods. We expect that Cy-DNBS serves as an appealing candidate for deciphering biothiols-related physiological and pathological processes.

Automated summary

A new near-infrared thioxanthene-hemicyanine dye (Cy-DNBS) has been developed for simultaneous fluorescence and photoacoustic imaging of biothiols. Upon treatment with biothiols, Cy-DNBS exhibits strong near-infrared absorption and a subsequent turn-on photoacoustic signal. Additionally, the fluorescence intensity of Cy-DNBS increases instantly. The dye has been successfully used for imaging endogenous and exogenous biothiols in cells and mice, as well as tracking biothiols upregulation in the liver of mice triggered by S-adenosyl methionine. Cy-DNBS shows great potential for studying biothiols-related physiological and pathological processes.