Photoswitchable Thermally Activated Delayed Fluorescence Nanoparticles for “Double‐Check” Confocal and Time‐Resolved Luminescence Bioimaging
Maolin Yu, Weili Zhao, Fan Ni, Qiang Zhao, Chuluo Yang
Abstract
Abstract Thermally activated delayed fluorescence (TADF) materials have attracted increasing attention due to their great potential in time‐resolved luminescence imaging (TRLI) in bioimaging. However, the triplet state (T 1 ) of delay fluorescence is quenched readily by oxygen and the autofluorescence of biological systems remains inevitable interference in luminescence imaging, which often reduces signal‐to‐noise ratio during biodetection. To address this issue, the authors design a two‐component photoswitchable TADF polymeric nanoparticle (PDFPNs) by covalently incorporating a well‐designed TADF molecule (PDC‐DA) and a photochromic spiropyran derivative (SPMA). The as‐prepared PDFPNs with a unique luminescent “double‐check” strategy exhibit dual‐color fluorescence and variable fluorescence lifetime upon fluorescence resonance energy transfer (FRET) process through external lights irradiation. The obtained PDFPNs display the advantages of negligible oxygen‐sensitivity, high FRET efficiency, rapid photoresponsiveness, outstanding photoreversibility, and prominent long‐term fluorescence stability. The established PDFPNs show promising application in the high‐contrast dual‐color confocal and time‐resolved luminescence bioimaging in oxygenic living cells.