Physico-chemical, antimicrobial and anticancer properties of silver nanoparticles synthesised from organ-specific extracts of Bidens pilosa L.

Abstract

There is an increasing commercial demand for nanoparticles synthesis by green as opposed to chemical methods, given the toxicity and contamination risks associated with the latter. This study compared the physico-chemical, antimicrobial and anticancer activities of silver nanoparticles (AgNPs) synthesised using organ-specific plant extracts in Bidens pilosa. Leaf, stem and root extracts were used as the reducing agent with varying concentrations of AgNO3 (1 mM and 2 mM, respectively). The synthesised AgNPs were subsequently characterised by UV–vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and Fourier transform infrared spectroscopy (FT-IR). UV–vis spectroscopy showed a surface plasmon resonance peak for the synthesised AgNPs at 410 nm using all organ extracts. TEM studies indicated that nanoparticles ranged from 1.00 to 62.01 nm, with an average particle size of 17.00 nm. Average particle size was larger at the higher AgNO3 concentration. The FTIR analysis confirmed the presence of carbonyl groups, proteins and aldehydes on nanoparticles produced using all extract types. The leaf extract derived nanoparticles displayed maximum percentage cell death (76.0 ± 4.5%) against bacteria and superior antifungal activity (94.8 ± 0.5%) at 200 μg/ml. Leaf extract derived NPs also displayed maximum anticancer potency (38.1 ± 2.3%). The differential bioactivities of NPs across the three organ extracts investigated here suggests that comparative studies on plant organ-specific synthesised NPs can help us maximize the antimicrobial and anticancer benefits of plant-derived NPs.