Near-Infrared Fluorescent and Photoacoustic Dual-Mode Probe for Highly Sensitive and Selective Imaging of Cysteine In Vivo

Cysteine (Cys) plays an important role in many physiological activities of human beings. Various diseases are always accompanied by abnormal levels of Cys. A series of Cys-responsive probes were recently developed. However, most fluorescent probes have many disadvantages and exhibit poor in vivo imaging. Therefore, a near-infrared fluorescence (NIRF)/photoacoustic (PA) dual-mode probe with high selectivity and sensitivity (limit of detection = 10.6 nM) toward Cys was developed in this study. The new Probe I interacted with Cys to activate NIRF/PA signals, detecting Cys in vitro with a large emission wavelength (851 nm) and Stokes shift (191 nm), monitoring the occurrence of liver cancer in vivo. This work not only presented an effective NIRF/PA dual-mode dicyanoisophorone probe for the first time in the imaging of Cys but also provided a comprehensive and accurate tool for detecting different analytes and tumors in deeper tissues, which could be conducive to the early diagnosis of diseases.