Effect of Noscapine Hydrochloride on the Near-Infrared Optical Properties of Indocyanine Green

Indocyanine Green (ICG) is a widely used near-infrared fluorophore in biomedical imaging and therapy due to its strong light absorption and effective heat conversion abilities. Recently, combination of chemotherapy with PTT (chemo-PTT) has emerged as a promising approach to improve cancer treatment effectiveness. This study investigates the interaction between Noscapine Hydrochloride (Np.HCl), a benzyl isoquinoline alkaloid with potential anticancer effects, and ICG, with a specific focus on its influence on ICG's optical properties. The findings indicate that Np.HCl promotes J-aggregation even at low concentrations, with aggregation intensity increasing proportionally to Np.HCl concentrations. A simple and reproducible method has been developed to synthesize these J-aggregates (IJAs) using FDA-approved agents, Np.HCl and ICG, highlighting their potential applications in improving chemotherapy outcomes. Spectral analysis revealed the presence of both blue and red shifts, depending on the dye concentration, indicating molecular interactions between Np.HCl and IGs, which were quantitatively assessed through Gaussian fitting. Additionally, Stern-Volmer plots were used to analyze the quenching dynamics and interaction mechanism. Further, cytotoxicity studies have been performed on H1299 cells, which revealed IC₅₀ values of 354.4 and 165.8 μM for ICG and Np.HCl, respectively. Notably, the combination treatment (ICG:Np.HCl) exhibited the highest cytotoxic effect, suggesting a potential synergistic interaction. This is the first demonstration of noscapine-driven ICG J-aggregation, creating a new scope for designing dye-drug assemblies with optical and therapeutic functions.