Tumor-Targeting Probe for Dual-Modal Imaging of Cysteine in Vivo

Cysteine (Cys) is a crucial biological thiol that hasa vital functionin preserving redox homeostasis in organisms. Studies have shown thatCys is closely related to the development of cancer. Thus, it is necessaryto design an efficient method to detect Cys for an effective cancerdiagnosis. In this work, a novel tumor-targeting probe (Bio-Cy-S)for dual-modal (NIR fluorescence and photoacoustic) Cys detectionis designed. The probe exhibits high selectivity and sensitivity towardCys. After reaction with Cys, both NIR fluorescence and photoacousticsignals are activated. Bio-Cy-S has been applied for the dual-modaldetection of Cys levels in living cells, and it can be used to distinguishnormal cells from cancer cells by different Cys levels. In addition,the probe is capable of facilitating dual-modal imaging for monitoringchanges in Cys levels in tumor-bearing mice. More importantly, theexcellent tumor-targeting ability of the probe greatly improves thesignal-to-noise ratio of imaging. To the best of our knowledge, thisis the first Cys probe to combine targeting and dual-modal imagingperformance for cancer diagnosis.