Near-infrared fluorescent probes: a next-generation tool for protein-labeling applications

Abstract

This minireview describes the development of NIR chemical probes for various protein-tag systems.

Super-Resolution Microscopy: Shedding New Light on In Vivo Imaging

“…For the past few decades, super-resolution fluorescence imaging has mainly located in the visible and several used near-infrared I light range ( Jin et al, 2018 ). Compared with the visible, red-shifting fluorophores including NIR I (650–950 nm) and NIR-II (1,000–1700 nm) light, would bear several virtues: 1) far-red light has lower scattering across tissues, enhancing tissue penetration and imaging depth; 2) auto-fluorescence caused by the excitation of molecules, like flavins or haemoglobin, is usually reduced in red-shifted wavelengths; 3) absorption of far-red light is less by the tissue when compared to shorter excitations, causing less phototoxic impact ( Lei and Zhang, 2020 ; Reja et al, 2021 ). Thus, shifting the excitation and emission wavelength of the probe to the red spectral region is necessary for in vivo imaging.…”

“…Second, the labeling probes possessing suitable spectroscopic and chemical properties has become a major bottleneck to unleash the full potential of SRMs. To create super-resolution maps of the local environment, both biologists and chemists could be stimulated to develop new labeling strategies that not only have far red emitting but also minimally disturb the tagged biomolecule ( Fernandez-Suarez and Ting, 2008 ; Wang et al, 2018 ; Reja et al, 2021 ). Third, improvements in real-time imaging combining with faster temporal resolution are necessary to resolve time dependent processes in vivo .…”

Near-infrared absorbing aza-BODIPYs with 1,7-di-tert-butyl groups by low-barrier rotation for photothermal application

“…[1][2][3] Owing to the near-infrared (NIR) absorption, high molar extinction coefficient and adjustable wavelength, aza-BODIPYs are widespreadly applied for the NIR dyes, fluorescent chemosensors, sensitized solar cells, photodynamic therapy (PDT) and photothermal therapy (PTT) and so forth. [4][5][6][7][8][9][10] These applications all directly reflect one or more of three pathways to return to the ground state from the excited state, that is, emitting photon (fluorescence), following non-radiative relaxation pathways (heat generation), or exiting from the singlet to the triplet state (T1) via intersystem crossing (ISC) to generate singlet oxygen with oxygen. [11][12][13][14][15] Recently, PTT and PDT, which correspond to the latter two pathways, have aroused widespread interest in phototherapeutic field.…”

Near-Infrared Fluorescent Probes for the Detection of Cancer-Associated Proteases

“…The first are always-on fluorophores, which can be used for cell tracking or to feature vascular distribution in heavily vascularized tumors. 22 Indocyanine Green (ICG) is the main FDA-approved NIR fluorophore to date and has been utilized in clinical studies to improve tumor resection by enhancing the contrast between tumor and healthy tissue. While the staining with ICG can provide significant benefit to surgeons, it cannot provide activity readouts of cellular processes within the tumor microenvironment.…”