Influence of polymer stabilizers on the morphology and antimicrobial activity of MgO nanoparticles
摘要
Magnesium oxide nanoparticles were prepared using a sol–gel route assisted by two different stabilizing matrices, namely Acacia nilotica Gum and polyvinyl alcohol (PVA), with the objective of understanding how polymeric environments influence particle formation and antimicrobial response. Phase analysis by X-ray diffraction confirmed the successful formation of single-phase cubic MgO (Fm–3 m) in both cases. The average crystallite size was estimated to be about 18 nm for gum-mediated MgO and 25 nm for PVA-stabilized MgO, indicating comparatively restricted crystal growth in the biopolymer-assisted system. Scanning electron microscopy showed clear morphological variation: MgO synthesized with Acacia nilotica gum displayed porous, irregular, and aggregated particles with 7.46 nm, while the PVA-assisted sample consisted of denser, more uniform particles with 8.1 nm. Fourier-transform infrared spectra confirmed Mg–O bonding along with surface hydroxyl groups and residual stabilizer-related functionalities. Antibacterial activity was examined against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis. The gum-mediated MgO exhibited inhibition zones of 22 ± 0.1, 16 ± 0.2, 18 ± 0.3, and 16 ± 0.1 mm, respectively, whereas the PVA-based sample showed inhibition zones of 20 ± 0.2, 16 ± 0.3, 18 ± 0.1, and 16 ± 0.2 mm. Moderate antifungal activity was observed against Candida albicans and Aspergillus niger. The relatively enhanced antibacterial response of MgO-Gum is attributed to its smaller crystallite size, porous structure, and improved interaction with microbial cell surfaces.