A high biocompatible near-infrared fluorescent probe for tracking cysteine in multi-biosystem and its application in cervical cancer imaging

[Display omitted] •A high biocompatible near-infrared fluorescent probe Cy7-SS was developed for in-vivo cysteine detection.•The probe has a low limit of detection (83 nM) and high selectivity for cysteine detection.•The probe has been successfully applied to the imaging cysteine in nematodes and cervical cancer tumors.•Fluorescent probe Cy7-SS has the potential to be further developed as a clinical diagnostic tool for cervical cancer. Cysteine (Cys) plays a crucial role in the biological system and many related diseases. However, the detection of Cys in living organisms are still hindered by shortage of small molecule fluorophores that exhibit excitation and emission in the near-infrared region. Herein, we designed and synthesized a high water-soluble Cys probe (Cy7-SS) based on heptamethine cyanine scaffold. The prepared Cy7-SS displayed an enhanced emission at near-infrared region (NIR) after the recognition of Cys. Moreover, Cy7-SS not only exhibited high selectivity and sensitivity on the detection of in vitro Cys, but also could be used for endogenous Cys in living cells and C.elegans. The prepared strategy for the design of fluorophores expands the in vivo sensing toolkit for the precise analysis in clinical diagnosis.