Effect of Environmentally Friendly Silver Nanoparticles Against of Multiple Drug Resistance Fungus

Bionanotechnology is a field that holds the potential to overcome challenges in medicine. Synthesized materials manipulated at the nanoscale can exhibit new phenomena and properties that interact with biological structures, leading to synergistic effects. These materials also demonstrate quantum effects, where energy behavior becomes discrete, and have a larger surface area-to-volume ratio than bulk materials, enhancing their surface properties and ability to interact catalytically with targets. However, the lethality of fungal diseases is increasing due to opportunistic infections, resistance to current treatments, and the systemic damage caused by antibiotics in the host organism.
Our project focused on synthesizing silver nanoparticles (AgNPs) through an eco-friendly, bottom-up approach based on green chemistry principles. We used a chemical reduction method with a 0.1M silver nitrate solution in analytical grade water and carrot extract (D. carota) as the reducing and stabilizing agent. The complex composition of carrot extract, primarily comprising ascorbic acid and polyphenols such as carotenoids and flavonoids, contributed to the synthesis process.
The formation of AgNPs was first observed through a color change of the solution from translucent to brown. We utilized characterization techniques such as UV-Vis spectroscopy, dynamic light scattering (DLS), Zetasizer, and transmission electron microscopy (TEM) to determine the morphology and size of the nanoparticles. Testing the antifungal potential, we found that the AgNP exhibited a UV-Vis absorbance peak at 430 nm, a charge of -24mV, and a size of 53.8 nm in solution, with a polydispersity index of 0.133. In the dry state, the size reduced to approximately 17 nm. The results showed promising antifungal activity against drug resistant strains of  C. neoformans, C. gattii, R. mucilaginosa, C. haemulonii, and C. auris, with inhibitory concentration values ranging from 6.2 µg/mL to 12 µg/mL, depending on the pathogen.

This work was supported by Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (203.950/2021).