Incubation period induced biogenic synthesis of PEG enhanced Moringa oleifera silver nanocapsules and its antibacterial activity

Abstract

Human pathogenic diseases are on the rage in the list of enfeebling diseases globally. The endless quest to salvage these drug-resistant pathogens ravaging our system through various therapies still posts serious challenge. This study engaged a biogenic synthesis that is benign, facile, biocompatible, cost-effective and eco-friendly to synthesized silver nanocapsule (AgNCs) via Moringa oleifera aqueous extract under incubation control. The flavonoid-kaempferol, phenolic-chlorogenic acid and tannin components of MO acted as the potential stabilizing and reducing agent in the formation of AgNCs. The formulated AgNCs was further functionalized with PVA, PVP and PEG for biocompatibility and dispersion enhancement. Various characterization techniques were used to determine the properties of AgNCs formulated. The absorbance due to the color change was observed by the UV-Visible spectroscopy with surface plasmons resonance peak between 425 and 455 nm. The Fourier transform infrared spectroscopy (FTIR) shows the various functional group responsible for the biogenic synthesis of AgNCs. The X-ray spectroscopy analysis shows a single phase cubic structure of AgNCs formed. The Scanning electron microscopy (SEM) image shows a rod-like nanocapsule of uniform grains. The antibacterial potency of AgNCs was proven against gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli and Coliform). The AgNCs inhibited the growth of the three human pathogens with Coliform showing the highest activity to the AgNCs with a minimum inhibitory dose of 15 μg/mL. It is noteworthy that the bacterial strains show functional susceptibility to the AgNCs at lower concentrations compared to the conventional antibacterial drugs. Consequently, AgNCs serve as an enhanced substitute for the conventional antibacterial drugs in therapeutic biomedical field sequel to its pharmacodynamics against the bacterial strains.