Facile Access to Far‐Red Fluorescent Probes with Through‐Space Charge‐Transfer Effects for In Vivo Two‐Photon Microscopy of the Mouse Cerebrovascular System

Abstract

Much effort has been devoted to the generation of fluorescent probes by synthetic approaches. In this study, we developed a facile strategy to construct far-red fluorescent probes based on through-space charge transfer within complexes of acceptors and donors and their "twist + twist" interactions. Owing to their rare two-photon excitation property, the complexes could be used for in vivo imaging of the mouse cerebrovascular system.

Effects of Halogenation on Quinoline‐Malononitrile‐based AIEgens: Photophysical Properties Investigation and Wash‐Free Imaging

“…DQM-OH, DQMF-OH, and DQMCl-OH were obtained by Knoevenagel condensation reaction of compound 3 with compounds 4 a, 4 b, and 4 c, respectively. The intermediates and final compounds were well-characterized by 1 H, 13 C, and 19 F NMR spectroscopy and HRMS in the Supporting Information (Figures S1-S14). In addition, we also confirmed the structure of DQM-OH, DQMF-OH, and DQMCl-OH by single-crystal structure analysis (Figure 1B).…”

“…Commercial Endoplasmic Reticulum probe ETR and Mitochondrial probe MTDR were purchased from Beyotime. 1 H NMR (400 MHz), 13 C NMR (100 MHz) and 19 F NMR (376 MHz) spectra were recorded on a Bruker AVANCE III spectrometer using tetramethylsilane as the internal standard. High-resolution mass spectra (HRMS) were recorded on an Agilent Technologies 6510 Q-TOF LC/ MS instrument operated in the ESI mode.…”

“…[7,[10][11][12] The mechanism of restriction of intramolecular motion (RIM) proposed by Tang et al has been widely accepted to explain the unique fluorescence of AIEgens. [7] Guided by the RIM mechanism, scientists around the world have made great efforts to develop various kinds of AIEgens, including siloles, [13][14][15] tetraphenylethylenes, [16][17][18] tetraphenylpyrazines, [19][20][21] acrylonitriles, [22][23][24] and metal complexes, [25][26][27] for molecule detection, bioimaging, disease diagnosis, and therapy. [28][29][30][31][32][33][34] Among these, the quinolinemalononitrile core developed by Zhu and co-workers has become an attractive building block for constructing multiple functional AIEgens, because of their facile synthesis and bright solid-state fluorescence.…”

Organic Nanoparticles with Aggregation-Induced Emission and Two-Photon Excitation for Fluorescence Imaging of Living Cells/Tissues

“…In recent years, some bioactive molecules, such as saponins, bovine serum albumin (BSA), and human serum albumin (HSA), are developed as carriers to deliver AIE-NPs into living cells/tissues due to their low cytotoxicity and good cell permeability. ,,, In addition, most of these AIE-NPs demonstrate red/near-infrared emission with low excitation energy, which can restrain the autofluorescence of biological media caused by high excitation energy such as UV irradiation. However, red/near-infrared emitting NPs generally suffer from their low fluorescence quantum yields and weak fluorescence, which limit their application in biological imaging for living cells. ,− …”

Green-Emitting Organic Nanoparticles with Aggregation-Induced Emission and Two-Photon Excitation for Fluorescence Imaging of Living Cells/Tissues

“…However, red/near-infrared emitting NPs generally suffer from their low fluorescent quantum yields and weak fluorescence, which limit their application in biological imaging for living cells. [11,[26][27][28] Herein, we report the synthesis of two-photon excited AIE NPs with green-emitting characteristic, which is of high fluorescent quantum yield and strong fluorescence. In one case, the two-photon excitation can effectively reduce the autofluorescence of biological media and thus the damage of living cells due to the near-infrared excitation wavelength beyond 800 nm.…”