High Antifungal Activity against Candida Species of Monometallic and Bimetallic Nanoparticles Synthesized in Nanoreactors

Among all novel challenges nowadays worldwide, infectious disease is probably one of the most important. It is well-known that common treatments used include high doses of antibiotics, which are very invasive therapies for patients. These treatments are more intensive when the infection is related to multidrug resistant microorganisms. In this sense, in this work we report the use of reverse micelles to form less than 5 nm gold, silver, and gold–silver nanoparticles (NPs) with biological activity against five opportunistic Candida strains responsible of several diseases in human beings. As a result, we evaluate the interface properties and droplet–droplet interactions of micelles founding high fluidity in the polar head of the surfactant, necessary to form a flexible interaction channel in the “dimmer” micelle–micelle. In this condition, we form monodispersed, highly reactive NPs with sizes less than 5 nm with high antifungal activity against C. parapsilosis, C. Krusei, C. glabrata, C. guillermondii, and C. albicans, with minimum inhibitory concentrations (MIC 50 ) less than 0.7 ppm in all cases, the lowest reported to the best of our knowledge. These are very promising results to develop alternative therapies to treat fungal diseases in humans, animals, and plants, or to coat conventional surfaces in surgery rooms.