Silver nanoparticle interaction with ergosterol induces cell death and
inhibits Trichosporon asahii cell proliferation
In the present study, we have synthesized silver nanoparticles using
Azadirachta indica (A. indica) skin extract as a reducing agent and
characterized it. The antifungal activity of the silver nanoparticles
was assessed against three different clinical isolates of T. asahii. The
silver nanoparticles showed an efficient antifungal activity against T.
asahii and, it was again established by time kill assay and
Post-AntiFungal Effect (PAFE). Synergistic effect of silver
nanoparticles with fluconazole or nystatin revealed a Minimum Inhibitory
Concentration (MIC) decrease by 4-fold for both drugs studied and
inhibited biofilm formation. An in vivo antifungal efficacy of silver
nanoparticles using female Balb/C mice model revealed a mean 4log
reduction of CFU in kidney when treated with 90mg/kg. Morphology changes
of T. asahii cells, treated with silver nanoparticles, were observed
using SEM. Cell membrane damage was quantified from the treated cells
using flow cytometry by a Propidium Iodide (PI) uptake assay. The
mechanism of action of the new silver nanoparticles against T. asahii
was interpreted, and we learnt that they directly bind to ergosterol.
Further, silver nanoparticles were not cytotoxic to normal cells (NIH
3T3) and hemocompatible. We concluded that the new silver nanoparticles
exhibited promising antifungal activity against T. asahii.