Rationally assembled albumin/indocyanine green nanocomplex for enhanced tumor imaging to guide photothermal therapy

Herein, a novel phototheranostic nanocomplex that is self-assembled from bovine serum albumin (BSA) and indocyanine green (ICG) is developed for enhanced near-infrared (NIR) fluorescence imaging, which benefits the guidance on in vivo cancer photothermal therapy (PTT). The study confirms that the binding of ICG with the bind sits on the albumin will result in improved hydrolytic stability and high photoluminescence quantum yield (PLQY). The ICG loading ratio in the nanocomplex is optimized and confirms the loading ratio of 0.5% ICG to be the optimal content. The optimized ICG–BSA nanocomplex (ICG–BSA NC) possesses a higher PLQY of 16.8% than that of free ICG (2.7%). The high PLQY and efficient passive targeting ability of ICG–BSA NC help improve its in vivo tumor accumulation and NIR fluorescence imaging significantly. Under laser irradiation, efficient PTT with obvious tumor growth suppression on a triple negative breast tumor model can be observed in the ICG–BSA NC treated group.