ComputationalDesign of Two-Photon Fluorescent Probesfor Intracellular Free Zinc Ions.

Two-photonfluorescence probes used in two-photon fluorescencemicroscopy (TPM) can achieve intact tissue imaging without destruction.Therefore, for a long time, TPM has been an important tool in biologyand medicine. In this background via a quantum chemical method, aseries of zinc ion probe molecules using N,N-di(2-picolyl)ethylenediamine (DPEN) as the recognitiongroup were studied, which are based on the photoinduced electron transfer(PET) mechanism. The fact that the one-photon absorption peak is almostunchanged and the fluorescence emission intensity increased significantlyupon coordination with a zinc ion reveals that these probes can bePET fluorescent bioimaging reagents. And it is predicted that whenthe chemically modified probe molecule is incorporated with Zn2+, the two-photon absorption (TPA) cross-section (δmax) will greatly increase and the TPA peak will be in thenear-infrared region. The molecules after changing the fluorophorebecome more suitable for probing Zn2+in vivo, and a modificationat the end of the fluorophore can fine-tune the fluorescence and TPAproperties. The detailed investigations will provide a theoreticalbasis for synthesizing new zinc-ion-responsive two-photon fluorescentprobes. [ABSTRACT FROM AUTHOR]