Photoswitchable Thermally Activated Delayed Fluorescence Nanoparticles for “Double‐Check” Confocal and Time‐Resolved Luminescence Bioimaging

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 (T1) 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.

Dibenzodipyridophenazines with Dendritic Electron Donors Exhibiting Deep-Red Emission and Thermally Activated Delayed Fluorescence

“…Materials exhibiting thermally activated delayed fluorescence (TADF) exhibit unique photophysics − that has recently unlocked applications spanning photocatalysis, , bioimaging, − photodynamic therapy, − and organic light-emitting diodes (OLEDs). − TADF can be observed when the energy gap between the lowest energy singlet (S 1 ) and triplet (T 1 ) excited states in a material is small enough to enable conversion of triplet excitons to singlets, by a process termed reverse intersystem crossing (RISC). This process can enable the harvesting of triplet excitons in purely organic materials, giving compounds that exhibit both prompt (ns) and delayed (μs–ms) emission lifetimes.…”

A Cu 2+ triggered reversible photochromic system: the structure photochromic response relationship study and potential applications

“…Due to their remarkable colour change after light stimulation, photochromic materials could be used in the preparation of molecular switches [2], optical data storage [6], molecular logic gates [6] and colorimetric chemo-sensors [7], etc. To date, organic photochromic materials with core structures such as diarylethene [8,9], rhodamine [10][11][12][13], spiropyran [14][15][16] and azobenzene [4,17] have been developed. Among those reported photochromic materials, rhodamine derivatives have received significant attention in consideration of their outstanding advantages such as simple synthesis, distinctive colour change and good recoverability.…”

Modulating the electron-donating ability of aggregation-induced emission molecules for improved photo-responsive properties

“…Taking advantage of their promising optical properties, AIE materials were widely used in biological imaging, optoelectronic devices, and smart materials. [25][26][27] Therefore, it is extremely desirable to combine the AIE characteristics and photo-responsive properties into a single molecule. Up to now, many photoresponsive molecules with AIE properties can undergo a Z/E isomerization, photocyclization, or photodimerization process.…”