NIR-II Fluorescent Biodegradable Nanoprobes for Precise Acute Kidney/Liver Injury Imaging and Therapy

NIR-II fluorescent nanoprobes based on inorganic materials, including rare-earth-doped nanoparticles, single-walled carbon nanotubes, CdS quantum dots (QDs), gold nanoclusters, etc., have gained growing interest in bioimaging applications. However, these nanoprobes are usually not biodegradable and lack therapeutic functions. Herein, we developed novel NIR-II fluorescence (FL) imaging and therapeutic nanoprobes based on black phosphorus QDs (BPQDs), which exhibited excellent biodegradability and high tunability of size-dependent optical properties. By adjusting the size of nanoparticles, BPQDs can specifically accumulate in the kidney or liver. Importantly, a low dosage of BPQDs can effectively protect tissues from reactive oxygen species (ROS)-mediated damage in acute kidney and liver injury, which was real-time monitored by responsive NIR-II fluorescence imaging. Overall, we developed novel NIR-II emitting and therapeutic BPQDs with excellent biodegradability vivo, providing a promising candidate for NIR-II FL imaging and ROS scavenging.

Activatable NIR-II Fluorescent Probes Applied in Biomedicine: Progress and Perspectives

With the advantage of inherent responsiveness that can change the spectroscopic signals from "off" to "on" state in responding to targets (e. g. biological analytes/microenvironmental factors), activatable fluorescent probes have attracted extensive attention and made significant progress in the field of bioimaging and biosensing. Due to the high depth of tissue penetration, minimal tissue damage and negligible background signal at longer wavelengths, the development of second near-infrared window (NIR-II) fluorescent materials provides a new opportunity to develop activable fluorescent probes. Here, we summarized properties, advantages and disadvantages of mainly NIR-II fluorophores (such as rare earth-doped nanoparticles, quantum dots, single-walled carbon nanotubes, small molecule dyes, conjugated polymers and gold nanoclusters), then overviewed current role and development of activatable NIR-II fluorescent probes (AFPs) for biomedical applications including biosensing, bioimaging and therapeutic. The potential challenges and perspectives of AFPs in deep-tissue imaging and clinical application are also discussed.