Bio-design of Ganoderma adspersum-grafted silver nanoparticles and assessment their anti-bacterial efficiency

Recently, the preparation of silver nanoparticles (Ag-NPs) using green nanotechnology has gained significant space and interest in the field of antibiotics due to their high and effective medicinal properties. In this novel study, the biomass of natural mushroom Ganoderma adspersum (GA) was utilized for the first time for designing of sustainable silver nanoparticles (SNPs) using the green approach principle. The biocomponents in biomass of GA extract (GAE) were played crucial role as reducing and capping agent for fabrication of SNPs. The formation of SNPs was confirmed through two-step: first, by visual observation of a color change, and second, by characterizing the morphology properties of the synthesized SNPs using a range of advanced analytical techniques. Visually, the transformation of the colorless silver ions solution to a dark brown color indicated successful SNP formation. This transformation was confirmed by UV-Vis spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), elemental mapping, and X-ray Diffraction (XRD) analysis. The characterization results revealed that the designed nanoparticles exhibited a strong localized surface plasmon resonance (LSPR) peak at 429 nm, further confirming successful synthesis. Besides, the SNPs were predominantly spherical, with an average size of 39 nm, indication on clean synthesis. All these recorded physicochemical properties of AgNPs were harnessed for evaluating its antimicrobial activity. The prepared SNPs and GAE were tested for their antimicrobial efficacy. Evaluation of SNPs as antibacterial agent was performed using different SNP concentrations (0.1 M and 0.2 M) via the agar well diffusion method. Both utilized dosages exhibited strong to moderate antibacterial effects against a wide range of bacterial strains, encompassing Gram-positive species (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes) as well as Gram-negative species (Escherichia coli, Pseudomonas aeruginosa). The inhibition zones recorded for the SNPs ranged from 12 mm to 38 mm, surpassing those observed for the GAE and standard antibiotics, highlighting the potent antibacterial properties of the synthesized nanoparticles. In addition, this research demonstrates a simple and economical green synthesis approach for producing silver nanoparticles with potential antimicrobial applications. However, further in-vivo investigations are necessary to validate their therapeutic effectiveness against multidrug-resistant pathogens.