In Situ Light-Triggered Synthesis of NIR-II Nanoprobes for Deep-Tissue Optical Imaging and Hepatic Photodistribution Mapping

Accurate assessment of light distribution within the body, particularly in deep tissues, is essential for early disease diagnosis and the advancement of light-based therapeutic strategies. The liver, as a central organ governing metabolism, detoxification, immunity, and coagulation, plays a vital role in maintaining physiological homeostasis. However, noninvasive visualization of light distribution in the liver remains a significant challenge. Herein, we report a strategy for imaging spatial light distribution in liver tissues using second-near-infrared (NIR-II) fluorescence imaging, enabled by specially designed photosensitive AgBr nanocrystals. Upon illumination with smartphone-emitted light, these nanocrystals undergo decomposition, generating Ag₂S quantum dots that emit in the NIR-II window. Following surface modification with PLGA, the AgBr nanocrystals were administered in vivo, allowing for the real-time visualization of light distribution within hepatic tissue and successful mapping of illumination patterns. This light-activated in situ synthesis of NIR-II-emitting nanoprobes offers a promising approach for the precise diagnosis of deep-tissue pathologies, therapeutic monitoring, and image-guided surgery.