LAUSR

Emergence of fluorescence imaging with real-time and in situ manners has revolutionized the fields of tracing and defining enzymes in biological systems. β-galactosidase is a kind of enzyme that plays vital roles in controlling multitudes of cellular functions and participating in disease pathogenesis. Thus, building fluorescent probes with high sensitivity and fidelity for visualizing β-galactosidase in biological systems is very significative. Herein, we engineered the first ultrsensitivity ratiometrc fluorescent probe CG based on ICT-FRET synergetic mechanisms for detecting β-galactosidase. The spectrum data show that probe CG has fast response (within 20s) as well as very low detection limit to β-galactosidase (0.081U/mL). Moreover, by calculation of a serious of kinetic parameters includ-ing Km (1.42 μM), kcat (7.04 s-1) and kcat/Km(4.96 μM-1. s-1), CG demonstrates high affinity and high catalytic efficiency to β-galactosidase. Owing to its excellent water solubility, CG has well biocompatibility to visualize the β-galactosidase in living cells. Furthermore, for imaging in bioapplications, CG is capable of detecting β-galactosidase not only in overexpressed cell lines but also in transient expressed cell lines. Significantly, CG can monitor β-galactosidase ex vivo selectively. We hope ongoing work to employing CG can be as an ultrasensitive powerful tool for further seeking the physiological and pathological functions in biological organisms.