Silver Nanoparticles, stabilized by Tetrapleura tetraptera from food waste, influence of extract on Nanoparticles' Surface Morphology and Antimicrobial properties

Abstract

Plant extracts provide a sustainable and eco-friendly route to forming silver (Ag) nanoparticles (NPs). Synthesizing stabilized and monodisperse Ag NPs using plant extracts is challenging as several and various polyhydroxy compounds of extracts produce non-uniform dispersed NPs. In this study, stabilized Ag NPs were biosynthesized from environmentally friendly, non-toxic, novel aqueous Tetrapleura tetraptera fruit extract. The role of synthetic conditions like concentration of silver nitrate and pH were also investigated. Phytochemical and FT-IR analyses revealed that the extract contained polyphenols, flavonoids, and other polyhydroxy compounds. UV-Vis spectra indicated a surface plasmon resonance band at 420 nm typical of Ag NPs, and together with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Energy Dispersive Spectroscopy (EDS), the patterns confirmed the formation of Ag NPs. The UV-Vis spectra and TEM micrographs showed that smaller, homogeneous, stabilized Ag NPs had an average particle size of 50 – 120 nm and 65 – 240nm (beyond 120nm is out of the range of nanoparticles). The Tetrapleura tetraptera extract made using 2.5 mM of AgNO3 at a pH of 11.5 exhibited superior antibacterial properties depicted by enhanced growth inhibition and significantly lower (P<0.05). The minimum inhibition concentration (MIC) was determined against gram-negative and positive bacteria relative to the synthesized NPs at different pHs. The studies demonstrated the potential of deploring Tetrapleura tetraptera extract stabilized Ag NPs as potential antimicrobial agents in packaging and biomedical applications.