Dual phototherapy of Leishmania major Promastigotes in the presence of Indocyanine Green -Loaded Nanomicelles

Objective(s): Due to its low toxicity and high absorbance in the near-infrared range, indocyanine green (ICG) has garnered significant attention for its applications in photodynamic therapy (PDT) and photothermal therapy (PTT). However, its tendency to aggregate in aqueous environments limits its biomedical applications. Encapsulating ICG in a biocompatible nanomicelle can improve its aqueous stability and photophysical properties. In the present study, the synergistic effect of ICG-loaded nanomicelles upon irradiation by an ۸۰۸-nm laser on Leishmania major (L. major) parasites was investigated. Materials and Methods: Initially, a nanomicelle comprised ICG was synthesized and characterized. Then, the temperature increase during irradiation and promastigote viability were evaluated. Subsequently, the in vitro dark toxicity and phototoxicity of the prepared samples were assessed via the MTS assay. Results: The absorbance of ICG-loaded nanomicelles at ۸۰۸ nm was more than ۲ times greater than Free-ICG. Also, the prepared formulation exhibited a mean diameter of ~۲۵ nm and a zeta potential of -۲.۳ ± ۱ mV. The combination of ICG-loaded nanomicelles and ۸۰۸ nm laser with a power density of ۲.۵ W cm−۲ led to a significant reduction in survival rate of promastigotes. Conclusion: The PDT/PTT mediated by ICG-loaded nanomicelles can be considered a promising and efficient therapeutic method for L. major, as it is inexpensive, safe, and easy to implement.