Green Synthesis and Biomedical and Environmental Remediation Applications of Phyto–Mediated Magnesium Oxide Nanoparticles

Magnesium oxide nanoparticles (MgO NPs) have garnered significant attention due to their exceptional thermal stability, biocompatibility, and versatile applications in biomedicine and environmental remediation. Conventional synthesis methods often involve toxic chemicals, high energy consumption, and complex instrumentation, limiting their sustainability. In contrast, green synthesis—utilizing plant extracts, bacteria, fungi, or algae—offers an eco-friendly, cost-effective, and scalable alternative. This review comprehensively examines recent advancements in the biosynthesis of MgO NPs, emphasizing their dual role in environmental and biomedical applications. In environmental remediation, MgO NPs exhibit remarkable photocatalytic efficiency in degrading organic pollutants such as industrial dyes (e.g., methylene blue, rhodamine B) and heavy metal ions (e.g., Pb²⁺, Cr⁶⁺) from wastewater, owing to their high surface area and redox-active surfaces. Their antimicrobial and antioxidant properties further enhance their utility in water purification technologies. In biomedicine, biosynthesized MgO NPs demonstrate potent antimicrobial activity against drug-resistant pathogens, anticancer effects through reactive oxygen species (ROS)-mediated apoptosis, and antioxidant capabilities that mitigate oxidative stress. Additionally, their biocompatibility supports potential applications in drug delivery, bioimaging, and tissue engineering. This review critically evaluates the advantages of biogenic synthesis over conventional methods, addressing challenges such as reproducibility, scalability, and long-term environmental impact. By integrating interdisciplinary insights, we highlight future directions for optimizing green synthesis protocols and expanding the multifunctional applications of MgO NPs in sustainable technologies.