Development of a Terbium Complex-Based Luminescent Probe for Imaging Endogenous Hydrogen Peroxide Generation in Plant Tissues

摘要

A highly sensitive Tb~(3+) complex-based luminescent probe, N,N,N~(1),N~(1)-[2,6-(3'- aminomethyl-1'-pyrazolyl)-4-(3",4"-diaminophenoxy)methylene-pyridine] tetrakis(acetate)-Tb~(3+) (BMTA-Tb~(3+)), has been designed and synthesized for the recognition and detection of hydrogen peroxide (H_(2)O_(2)) in aqueous solutions. This probe is almost nonluminescent because the Tb~(3+) luminescence is effectively quenched by the electron-rich moiety, diaminophenyl, on the basis of the photoinduced electron transfer (PET) mechanism. In the presence of peroxidase, the probe can react with H_(2)O_(2) to cause the cleavage of the diaminophenyl ether, which affords a highly luminescent Tb~(3+) complex, N,N,N~(1),N~(1)-[2,6-bis(3'-aminomethyl-1'-pyrazolyl)-4-hydroxymethyl-pyridine] tetrakis-(acetate)-Tb~(3+) (BHTA-Tb~(3+)), accompanied by a 39-fold increase in luminescence quantum yield with the increase of luminescence lifetime from 1.95 to 2.76 ms. The dose-dependent luminescence enhancement of the probe shows a good linearity with a detection limit of 3.7 nM for H_(2)O_(2), which is approximately 14-fold lower than those of the commonly used fluorescent probes. The probe was used for the time-resolved luminescence imaging detection of the oligosaccharide-induced H_(2)O_(2) generation in tobacco leaf epidermal tissues. On the basis of the probe, a background-free time-resolved luminescence imaging method for detecting H_(2)O_(2) in complicated biological systems was successfully established.