Comparative Study of Effects of Endophytic Fungal Silver Nanoparticles and Nanoemulsion on Escherichia coli

Green nanotechnology, a branch of nanotechnology, makes use of extract from plants or microorganisms to synthesize nanoparticles. This approach is eco-friendlier and more cost-effective than conventional methods of nanoparticle synthesis. Silver nanoparticles have interested researchers because several studies suggest that they have a wide range of applications in the field of medicine; it is known to serve as a good antimicrobial agent. This study concentrated on the synthesis of silver nanoparticles and nanoemulsion from the extract of an endophytic fungi-Lasiodiplodia theobromae. Nanoemulsion was prepared using an essential oil-tea tree oil from Melaleuca alternifolia (commonly known as tea tree). The nanoparticles were characterized using UV-visible spectra, SEM, FESEM, EDAX, XRD, and FTIR analysis. A comparative antimicrobial study was carried out between endophytic fungal extract-derived nanoparticles (EFNP) and nanoemulsion (EFNE) against two strains of Escherichia coli, through various experimental assays including Agar well diffusion method and assays that determined the minimum inhibitory concentration, minimum bactericidal concentration, and biofilm formation. From the results obtained, it was evident that both EFNP and EFNE had antibacterial activity and that the EFNE worked better than the former. This study suggested that EFNE was a good antibiotic alternative, and further in vivo studies must be done to check the efficacy.