Development and preliminary validation of a fluorescent probe for cysteine detection with potential applications in osteosarcoma and liver disorders imaging

In cancer biology, cysteine (Cys) is pivotal in maintaining the redox balance within tumor cells. To explore alterations in Cys concentration within osteosarcoma (OS) and hepatocellular carcinoma (HCC) cells, we devised a novel fluorescent (FL) probe named JYL-Cys , utilizing a thiol-sensitive dye, which specifically reacts with Cys to emit FL at 718   nm (λ ex = 660   nm). JYL-Cys exhibits a high response fold, a low limit of detection (0.15   μM), high selectivity, and effectively detects Cys under physiological conditions. A comprehensive suite of in vitro experiments, encompassing cell uptake studies and FL imaging analysis, was executed to assess the responsiveness of JYL-Cys across various cancer cell lines, specifically the OS cell line MG-63 and the HCC cell line HepG2. Furthermore, in vivo mouse model experiments were conducted to validate the probe's applicability and safety in live organisms. The probe demonstrated exceptional capability in visualizing the distribution of Cys within both OS and HCC cells through imaging, revealing markedly elevated Cys levels compared to normal cells. Notably, in vivo experiments confirmed the probe's safety for biological applications. Our experimental findings underscore that JYL-Cys is a valuable resource for delineating the biological significance of Cys in cancer progression and establish a foundation for future clinical applications, encompassing early diagnosis and prognosis assessment.