Green synthesis of silver nanoparticles using the mushroom fungus Schizophyllum commune and its biomedical applications

Abstract

Silver nanoparticles, which are small metallic colloidal particles, ranging 1 ∼ 100 nm in size, have several nano biotechnological applications in medicine, manufacturing and engineering industries. Fungus-mediated synthesis of silver nanoparticles is an ecofriendly, green process. Further, extracellular enzymes and proteins elaborated by fungi are involved in the synthesis of the silver nanoparticle, which makes the downstream processing relatively simpler. In the present investigation, Schizophyllum commune, a mushroom fungus, was tested for its ability to synthesize extracellular as well as intracellular silver nanoparticles. When the fungus was challenged with 1 mM silver nitrate, a change in colour of the broth and the mycelium was observed, indicative of extracellular and intracellular synthesis of silver nanoparticles. The presence of silver nanoparticles was confirmed by studying its Surface Plasmon Resonance absorption band in the visible wavelength. FTIR spectrum analysis of the silver nanoparticles indicated the presence of biomolecules in association with the reduction of silver ions. Scanning Electron Microscopic analysis of the silver nanoparticles revealed the nanorange dimensions of both the extracellular and the intracellular silver nanoparticles. Analysis of biological activities of the silver nanoparticles disclosed their significant antibacterial activity against Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas fluorescens. Additionally, the silver nanoparticles inhibited the growth of the dermatophytic fungal pathogens viz. Trichophyton simii, Trichophyton mentagrophytes and Trichophyton rubrum significantly. Anticancer activity of silver nanoparticles, assayed through MTT cytotoxicity assay, uncovered that 27.2 and 64% mortality could be obtained in Human Epidermoid Larynx Carcinoma (HEP -2) cell lines at concentrations between 10 and 100 µg/mL, respectively. The results obtained indicate that Schizophyllum commune is capable of synthesizing silver nanoparticles in shaken broth cultures (120 rpm) at 25 ± 2℃ and pH 7.