Activatable Near-Infrared Fluorescent and Photoacoustic Dual-Modal Probe for Highly Sensitive Imaging of Sulfatase In Vivo

Sulfatase is an important biomarker closely associatedwith variousdiseases. However, the state-of-the-art sulfatase probes are plaguedwith a short absorption/emission wavelength and limited sensitivity.Developing highly sensitive fluorescent probes for in vivo imagingof sulfatase remains a grand challenge. Herein, for the first time,an activatable near-infrared fluorescence/photoacoustic (NIRF/PA)dual-modal probe (Hcy-SA) for visualizing sulfatase activity in livingcells and animals is developed. Hcy-SA is composed of a sulfate estermoiety as the recognition unit and a NIR fluorophore hemicyanine (Hcy-OH)as the NIRF/PA reporter. The designed probe exhibits a rapid response,excellent sensitivity, and high specificity for sulfatase detectionin vitro. More importantly, cells and in vivo experiments confirmthat Hcy-SA can be successfully applied for PA/NIRF dual-modal imagingof sulfatase activity in living sulfatase-overexpressed tumor cellsand tumor-bearing animals. This probe can serve as a promising toolfor sulfatase-related pathological research and cancer diagnosis.