A novel fluorescent probe for rapid detection of sulfatase in vitro and in living cells

Sulfatase participates in a variety of physiological processes in organisms including hormone regulation, cell signaling, and bacterial pathogenesis. Current sulfatase fluorescent probes can be used to track sulfate esterase overexpression in cancer cells for diagnostic purposes and to understand the pathological activity of sulfate esterase. However, some sulfatase fluorescent probes based on the hydrolysis of the sulfate bond were easily disturbed by the catalytic activity of sulfatase. Herein, we developed the fluorescent probe BQM-NH2 for sulfatase detection, which was based on the quinoline-malononitrile. The probe BQM-NH2 showed a fast response to sulfatase within 1 min and satisfactory sensitivity with a calculated LOD of 1.73 U/L. Importantly, it was successfully used to monitor endogenous sulfate in tumor cells, indicating BQM-NH2 has the potential to monitor sulfatase under physiological and pathological conditions.