Probes for Peroxynitrite Using Two-Photon Microscopy

Abstract

Two-photon microscopy (TPM), utilizing two near-infrared (NIR) photons as the excitation source, has become a useful tool for biomedical research. However, only a few two-photon excitable probes for peroxynitrite have been developed that can detect peroxynitrite in various biological conditions using two-photon microscopy. However, two-photon peroxynitrite probe with an improved two-photon absorbing property is still required for further exploration. Recently, it was reported that peroxynitrite can trigger oxidative N-dearylation reaction which can be used to induce fluorescence turn-on response. Thus, we have developed a new probe that can selectively detect peroxynitrite among other ROS/RNSs (Reactive oxygen/nitrogen species) utilizing dearylation reaction. The probe is highly selective and sensitive to peroxynitrite and has better two-photon excitation properties than any previous reported probes. Further, we synthesized two-photon excitable lanthanide complexes to introduce unique properties of lanthanide phosphorescence- Sharp, line-like emission bands with the same fingerprint wavelengths and narrow peak widths, and long excited-state lifetimes in the ms~μs range. With further modification, these lanthanide based two-photon probes can be used to discover the effects of peroxynitrite in biological systems which are not clearly understood.