Pea Protein/Gold Nanocluster/Indocyanine Green Ternary Hybrid for Near-Infrared Fluorescence/Computed Tomography Dual-Modal Imaging and Synergistic Photodynamic/Photothermal Therapy

Developments in technology such as theranostic nanoplatforms, which combine complementary imaging modalities and synergistic therapies, have brought new hope to the diagnosis and treatment of cancer, one of the most deadly diseases. In this article, a nanoplatform (AuNCs/PPI-ICG nanohybrid) with a theranostic effect was prepared using indocyanine green (ICG), a cyanine dye with bright near-infrared fluorescence (NIRF) and excellent photodynamic and photothermal performance, and it was loaded onto gold nanoclusters/pea protein isolate hybrid nanoparticles (AuNCs/PPI NPs). There was a linear relationship between ICG loading ratio and the concentration, within a concentration range of 0–5 mg/mL, making it possible to precisely control the concentration of loaded ICG. In addition, the AuNCs/PPI-ICG nanohybrid displayed outstanding loading stability and enhanced the aqueous stability of ICG, owing to the protectivity of AuNCs/PPI NPs. In vitro cell experiments showed that this biocompatible nanohybrid could be taken up by A549 cells and used as a fluorescent bioimaging probe. Moreover, because of Au, AuNCs/PPI NPs could also act as a potential computed tomographic (CT) contrast agent, and so the AuNCs/PPI-ICG nanohybrid had the potential to function as a dual-modal imaging agent. Finally, the as-prepared hybrid, with excellent photodynamic properties and exceptional photothermal capabilities, showed a satisfactory therapeutic effect in ablating A549 cancer cells. These results convincingly demonstrate that the AuNCs/PPI-ICG nanohybrid is a promising theranostic nanoplatform for NIRF/CT dual-modal imaging and for synergistic photodynamic therapy/photothermal therapy (PDT/PTT).