Nano-based antileishmanial agents: A toxicological study on nanoparticles for future treatment of cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is endemic in the tropical and subtropical countries. Antileishmanial drugs that are traditionally used for treatment of CL are mainly toxic, ineffective for some parasite isolates, and mostly expensive. Previous studies showed that some metal and metal oxide nanoparticles have antimicrobial activity. Moreover, the use of nanoparticles together with ultra violet (UV) and infra red (IR) light increases toxic effects of nanoparticles by generation of reactive oxygen species (ROSs) and heat, respectively. There is little information on antileishmanial activity of nanoparticles, alone or together with UV/IR. Thus, the purpose of this research was to study antileishmanial effects of some nanoparticles including silver nanoparticles (Ag NPs), gold nanoparticles (Au NPs), titanium dioxide nanoparticles (TiO₂ NPs), zinc oxide nanoparticles (ZnO NPs), and magnesium oxide nanoparticles (MgO NPs) on Leishmania major parasites under UV, IR, and dark conditions. After 24 h exposure to nanoparticles, different biological parameters such as cell viability, proliferation, infectivity, and infection index were investigated under UV/IR/dark conditions. In this study, the highest antileishmanial activity was seen for Ag NPs, followed by Au NPs, TiO₂ NPs, ZnO NPs, and MgO NPs. Both UV and IR light increased antileishmanial properties of all nanoparticles. In spite of antileishmanial activity of nanoparticles under UV, IR, and dark conditions, these nanoparticles had high cytotoxicity on macrophages, which must be considered in future studies. The authors declare that the use of nanoparticles for treatment of CL may have both positive and negative consequences.