Exploiting the Biogenic Potential of <i>Spirulina platensis</i> for the Sustainable Synthesis of Multifunctional and Bioactive Magnesium Oxide Nanoparticles

Abstract

ABSTRACT Antimicrobial resistance, largely driven by bacterial biofilm formation, remains a major challenge in treating immunocompromised patients, including those undergoing cancer therapy. In this study, magnesium oxide nanoparticles (MgO NPs) were synthesized via a green approach using Spirulina platensis extract. X‐ray diffraction, Fourier‐transform infrared spectroscopy, and scanning electron microscopy confirmed their crystalline structure, uniform spherical morphology, and an average size of 20.19 nm. The NPs exhibited notable antioxidant activity (IC 50 = 82.75 µg/mL, DPPH assay) and strong reducing power in the ferric reducing antioxidant power assay. Antimicrobial testing showed broad‐spectrum activity against Gram‐negative and Gram‐positive bacteria as well as Candida albicans , with a low minimum inhibitory concentration value (7.81 µg/mL). Moreover, MgO NPs disrupted preformed biofilms with 77.6% inhibition. Anticancer activity evaluation on HT‐29 colorectal adenocarcinoma cells revealed dose‐dependent cytotoxicity at 24 h, while non‐cancerous cells retained high biocompatibility. Collectively, these findings highlight the potential of green‐synthesized MgO NPs as eco‐friendly multifunctional agents against biofilm‐associated infections and cancer.