Efficient two-photon fluorescent probe for measuring γ-glutamyltranspeptidase activity during oxidative stress process in tumor cells and tissues
Oxidative stress, a disturbance in the balance between oxidant/antioxidant ratio, is associated in cancer, aging, inflammation, neurodegenerative diseases and other conditions. γ-Glutamyltranspeptidase (GGT) is a redox-related enzyme that plays a key role in mitigating the effects of oxidative stress by maintaining cellular glutathione (GSH) metabolism and homeostasis. Therefore, oxidative stress will upregulate the intracellular GGT level. To better understand major pathophysiological resist mechanism to oxidative injury in mediating many disease states, we designed and synthesized a novel two-photon (TP) fluorescent turn-on probe, Np-Glu, for GGT detection and bioimaging. Under the optimized conditions, Np-Glu exhibited remarkable fluorescence enhancement (∼150-fold), good selectivity and high sensitivity (LOD is 0.033 U L-1), with a wide linear concentration range (0-50 U L-1). More importantly, probe Np-Glu was successfully applied in one-photon and TP fluorescence imaging of GGT activity in oxidative stress model in living cells and tissues, suggesting Np-Glu as an ideal indicator for clinical and biological samples.