Synthesis, Characterization, In Vitro Safety Profile and Antimicrobial Activity of Green Magnesium Oxide Nanoparticles from Aloe vera Extract

Skin infections and the treatment of complex wounds represent a critical global public health challenge, exacerbated by an aging population and rising antimicrobial resistance to conventional treatments. Although nanotechnology has gained prominence in developing antimicrobial biomaterials, most traditional methods for synthesizing magnesium oxide nanoparticles (MgO-NPs) use toxic chemical reagents and lack in-depth assessments of cellular biosafety. Against this backdrop, current research has focused on green synthesis routes using natural extracts. The originality of this study lies in the novel biosynthesis of MgO-NPs mediated by Aloe vera extract, which acts as both a reducing and stabilizing agent, combining detailed morphological characterization with an assessment of biocompatibility and safety in human cells and potent activity against multidrug-resistant pathogens, thereby offering a sustainable and safe alternative for tissue engineering and wound healing. XRD diffractograms confirmed the crystalline structure of MgO-NPs at 36.9°, 42.9°, and 62.3°; morphological analysis revealed that MgO-NPs exhibited a predominantly spherical structure with an average size of 39.3 nm and heterogeneous morphology; and EDX results showed a composition of approximately 40.31 wt.% magnesium and 43.01 wt.% oxygen, confirming the elemental purity of the synthesized nanoparticles. The in vitro safety profile was assessed using HaCaT cell lines (12.5 to 400 µg mL −1 ), where MgO-NPs were biocompatible, with no significant cytotoxic effects observed at the tested concentrations, even after extended exposure periods (24 to 72 h). MgO-NPs exhibited a concentration-dependent antimicrobial effect against Staphylococcus aureus , Escherichia coli , Pseudomonas aeruginosa, and Candida auris . The MIC showed that MgO-NPs were more effective against Gram-positive bacteria (4.25 µg mL −1 ) than against Gram-negative bacteria (4.25 µg mL −1 and 8.50 µg mL −1 for E. coli and P. aeruginosa , respectively). These results highlight the promising characteristics of biosynthesized MgO-NPs for biomedical applications, especially in wound healing, due to their suitable morphology, biocompatibility, and antimicrobial potential.