Indocyanine green-incorporated exosomes for improved in vivo imaging of sentinel lymph node

Abstract

For improved physical stability and fast accumulation in sentinel lymph nodes in vivo, indocyanine green (ICG) was incorporated into exosomes (EXOs) to form a novel ICG-based near-infrared fluorescence probe. Compared with free ICG, prepared ICG-TBAI-encapsulated EXOs (ICG/EXOs) smaller than 50 nm had greater physicochemical stability in aqueous solution when exposed to light at 37 °C. In addition, sentinel lymph nodes were visualized within minutes with ICG/EXOs at a low ICG dose (0.05 mg/kg) owing to its well-controlled size distribution. Taken together, the results show that ICG/EXOs are effective biocompatible and sensitive near-infrared probes for real-time sentinel lymph node imaging in vivo.