Biosynthesis, Characterization and Antibacterial Efficacy of Silver Nanoparticles Derived from Endophytic Fungi against P. gingivalis

Introduction: Microbial resistance to existing antimicrobial agents in periodontal therapy is a growing problem. Therefore, there is a need for development of new antimicrobial agents.

Aim: To biosynthesize and characterize Silver Nanoparticles (AgNPs) using endophytic fungi and to evaluate the antibacterial efficacy against P. gingivalis.

Materials and methods: Cut leaf segments of Withania Somnifera (Ashwagandha) were used to isolate the fungi. Fresh cultures of fungi were inoculated in Erlenmeyer flask of 100 ml Malt Glucose Yeast Peptone (MGYP) broth and incubated at 29°C for 72 hours for the biomass to grow. Biomass was filtered and cell free fungal filtrate was used further. Biosynthesized AgNPs were characterized by visual observation, Ultraviolet-Visible (UV-Vis) spectrophotometer, Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction Analysis (SAED) and Fourier Transform Infrared Spectroscopy (FTIR). Antibacterial efficacy was evaluated by agar diffusion method measuring the zone of inhibition. The study groups included different concentrations of AgNPs: A (20 μl), B (40 μl), C (60 μl), D (80 μl) and E (100 μl) of AgNPs, F (0.2% CHX), G (2% CHX), H (Ampicillin) and I (sterile distilled water). The data collected for inhibition zones were statistically analysed using One-way Anova followed by Tukey post-hoc multiple comparison tests.

Results: The fungi were identified as Fusarium semitectum. Characterization studies showed the colour change from colourless to reddish brown; U-V spectrum showed peak 420 nm, TEM revealed the particles spherical in shape and 10-20 nm in size. FTIR analysis revealed the presence of functional groups. AgNPs 80 μl and 100 μl showed mean zone of inhibition 17.33 and 18 mm against P. gingivalis. CHX (0.2%) 17.85 and CHX (2%) 19.97 mm, Ampicillin 20.5 mm and no zone for sterile distilled water.

Conclusion: Biosynthesized AgNPs showed efficient antibacterial efficacy against P. gingivalis hence, creates a new horizon in periodontal therapy.