The antimicrobial activity of zinc oxide nanoparticles synthesized with plant extracts against Staphylococcus aureus
MetadataShow full item record
Nanoparticles using a green synthesis production method is of increasing interest for biomedical applications. Zinc oxide is currently used in medicinal and cosmetic formulations, and zinc oxide nanoparticles have potential in biomedical applications. Antibiotic-resistant bacterial infections are of growing concern globally, and novel antimicrobial agents are drastically needed. In this work, zinc oxide nanoparticles were synthesized using Calendula officinalis flowers aqueous extract and zinc nitrate hexahydrate using a single-pot green synthesis approach. The synthesized particles were calcined and characterised using UV-Vis spectrophotometry, Dynamic Light Scattering (DLS), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), Fourier-Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance Imaging (NMR). Quasi-spherical, hexagonal phase zinc oxide nanoparticles with core size <10nm according to TEM and average size of ~53nm according to XRD were successfully synthesized. The particles tended towards agglomeration. Antioxidant assays were run to determine the reducing power, antioxidant activity, and presence of polyphenols in the final products. The final product possessed antioxidant activity, polyphenols and had reducing power, confirming the constituents from Calendula officinalis playing a role in the reduction of the zinc ions and capping of the zinc oxide nanoparticles. Minimum inhibitory concentration of the samples by tube dilution was conducted to determine potential of the samples as antimicrobial agent against methicillin-resistant Staphylococcus aureus, using Clindamycin as control. Results of antimicrobial studies indicate the need for investigation of MIC using a variety of concentrations of the samples, and a variety of solvents, in order to determine exact MIC values. Further work is needed to improve the methodology to obtain particles that have a narrow size distribution, that are well dispersed, and are of higher concentration to be considered for antimicrobial use in the biomedical field.