Themed collection Near-infrared (NIR) luminescent probes for bioimaging and biosensing

Fan Zhang and Ben Zhong Tang introduce the Chemical Science themed issue on Near-infrared luminescent probes for bioimaging and biosensing.

Small-molecule based fluorescent probes are increasingly important for the detection and imaging of biological signaling molecules due to their simplicity, high selectivity and sensitivity, whilst being non-invasive, and suitable for real-time analysis of living systems.

In vivo imaging is a powerful approach to study biological processes.

Near-infrared fluorescent molecular probes with improved imaging depth and optimized biodistribution have been reviewed, showing great potential for diagnosis of nephro-urological diseases.

Fluorescence imaging in the second near-infrared (NIR-II, 1000–1700 nm) window has exhibited advantages of high optical resolution at deeper penetration (ca. 5–20 mm) in bio-tissues owing to the reduced photon scattering and tissue autofluorescence.

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

Structural and process controls of NIR-II AIEgens realize manipulating of radiative (R) and nonradiative (NR) decay for precise theranostics.

Near-infrared room-temperature phosphorescence was achieved by employing iodine substituted Bodipy into amorphous polymers. The self-healable gels were also obtained with the incorporation of a crosslinker and quadruple hydrogen bond based moieties.

An aggregation-induced emission (AIE) dye-powered afterglow luminogen has been designed for in vivo tumor imaging. The underlying afterglow mechanism can be described as a closed-loop of “photon–¹O₂–SP intermediates–photon”.

Far-red/NIR emitting, two-photon absorbing, biostable aminosilapyronin dyes (ASiP^j) and their derivatives (NIR-ASiP^j) offer novel (ratiometric) bioimaging platforms.

Tricoordinate boron imparts near-infrared absorption/emission and unusual multi-stage changes in the photophysical properties to fluorescein dyes.

A molecular design strategy is established to access diverse enzyme-activated probes that are excitable and emit in the NIR (I and II) region with favorable Stokes shifts, enabling targeted cancer imaging by real-time monitoring enzyme activities.

A novel NIR-II theranostic nanoprobe, PSY (∼110 nm), was concisely developed, which demonstrated excellent photostability, high tumor uptake, superior S/N ratios and more efficient cancer treatment with minimal side effects than cisplatin.

Chemiluminescence offers advantages over fluorescence for bioimaging, since an external light source is unnecessary with chemiluminescent agents.

In this work, a novel NIR two-photon fluorescence probe DCM-APN is reported for tracking APN in vitro and in vivo.

Tissue-penetration-depth-independent self-luminescence is highly expected to perform photoisomerization-related bioapplications in vivo to overcome the limitation of shallow tissue-penetration from external photoexcitation.

Novel biocompatible NIR-II aggregation-induced emission dots are facilely assembled and used for NIR-II biomedical fluorescence imaging.

This article presents the first work to fundamentally study the effect of steric hindrance in Pdot systems.

Non-toxic covalent organic nanosheet-based fluorescent nuclear stains.

Aptamer conjugated porphyrinic metal–organic framework (MOF) achieved target-induced bioimaging and photodynamic therapy.

Tricarbocyanine N-triazoles are first described as rationally-designed structures to overcome the limitations of NIR dyes for long-term in vivo imaging.

Development of molecular probes for the detection of reactive oxygen and nitrogen species (RONS) is important for the pathology and diagnosis of keloid diseases.

A new strategy that integrates the targeting group and response moiety together for the preparation of mitochondrial probe was developed. Bioimaging studies have shown that for the first time, the newly designed probe HDFL-Cys can first accumulate in mitochondria and then react with the analyte.

We report the controlled synthesis of monodisperse NaCeF₄:Er/Yb nanoprobes that exhibit intense NIR-II emission for in vitro bioassay and in vivo bioimaging.

We report three synthetic methods to prepare biocompatible Yb³⁺ complexes, which displayed high NIR luminescence with quantum yields up to 13% in aqueous media. This renders β-fluorinated Yb³⁺ porphyrinoids a new class of NIR probes for living cell imaging including time-resolved fluorescence lifetime imaging.

Introduction of an isopropyl bridge in the triangulenium skeleton leads to a new series of redshifted triangulenium dyes with high fluorescence quantum yields and remarkable long fluorescence lifetime allowing for time-gated cell imaging.

A yolk-like nanocapsule with responsiveness to tumor microenvironment and NIR photons was invented by integrating a tumor-responsive photothermal agent on Mn-doped UCNPs@mSiO₂ nanospheres for multiple imaging guided thermo-chemotherapy.

PDFT1032, a new semiconducting polymer possessing a favorable absorption peak (1032 nm) and outstanding biocompatibility, may be widely applicable in clinical imaging and the surgical treatment of malignancy.

A successful strategy for the design of ultrabright red luminogens with aggregation-induced emission (AIE) features is reported. The AIE dots can be utilized as efficient fluorescent probes for in vivo deep-tissue imaging with high penetration depth and high contrast.