A General Strategy for Development of Activatable NIR-II Fluorescent Probes for In Vivo High-Contrast Bioimaging.

Organic dye based NIR-II fluorescent probes, owing to their high signal-to-background ratio and deeper penetration, are highly useful for deep-tissue high-contrast imaging in vivo. However, it is still a challenge to design activatable NIR-II fluorescent probes. Here, a novel class of polymethine dyes (NIRII-RTs), with bright (quantum yield up to 2.03 %), stable, and anti-solvent quenching NIR-II emission, together with large Stokes shifts, was designed. Significantly, the novel NIR-II dyes NIRII-RT3 and NIRII-RT4, equipped with a carboxylic acid group, can serve as effective NIR-II platforms for the design of activatable bioimaging probes with high contrast. As a proof of concept, a series of target-activatable NIRII-RT probes (NIRII-RT-pH, NIRII-RT-ATP and NIRII-RT-Hg) for pH, adenosine triphosphate (ATP), and metal-ion detection, were synthesized. By applying the NIRII-RT probe, the real-time monitoring of drug-induced hepatotoxicity was realized.

Synergistic phototherapy of NIR wavelength xanthene-quinoline salt-based heavy-atom-free photosensitizers for tumor therapy.

We propose a practical strategy to design a series of heavy-atom-free synergistic phototherapy agents (CSQs) with both photodynamic therapy (PDT) and photothermal therapy (PTT) under NIR wavelength excitation by simply replacing the indole salt of xanthene Changsha (CS) with quinoline salt.