Cherenkov Radiation-Mediated In Situ Excitation of Discrete Luminescent Lanthanide Complexes

摘要

Lanthanide luminescence, while ideal for in vivo applications owing to sharp emission bands within the optical window, requires high-intensity, short-wavelength excitation of small organic "antenna" chromophores in the vicinity of the lanthanide complex to access excited f-orbital states through intersystem crossing. Herein, we explored Cherenkov radiation of the radioisotopes F-18 and Zr-89 as an in situ source of antenna excitation. The effective inter-and intramolecular excitation of the terbium(III) complexes of a macrocylic polyaminocarboxylate ligand (hydration number (q) = 0, quantum yield (phi) = 47%) as well as its analogue functionalized to append an intramolecular Cherenkov excitation source (q = 0.07, phi = 63%) was achieved. Using conventional small-animal fluorescence imaging equipment, we have determined a detection limit of 2.5 nmol of Tb(III) complex in presence of 10 mu Ci of F-18 or 89Zr. Our system is the first demonstration of the optical imaging of discrete luminescent lanthanide complexes without external short-wave excitation.