Systematic review of wettability enhancement, interface engineering and fabrication of magnesium oxide-coated graphene nanoplatelets in AZ91 matrix composites

The future calls for smart, sustainable, high‑performance, biodegradable materials that integrate seamlessly into biomedical and engineering applications. Magnesium oxide (MgO)-coated graphene nanoplatelet (GNP) reinforced AZ91 matrix composites have emerged as a promising candidate. However, persistent challenges of poor wettability and unstable interfacial bonding hinder their potential. These shortcomings restrict efficient load transfer and uniform dispersion. This systematic review of transformative, cutting-edge research provides a consolidated foundation for future experimental and computational breakthroughs that unlocks new horizons in biomedical and engineering applications. It uniquely synthesizes advances in wettability enhancement, interface engineering, and fabrication approaches, identifying critical challenges and charting pathways for sustainable performance. Methodological robustness was ensured using validation technique that relied on multiple databases of Scopus and Web of Science. Strong thematic consistency across databases was found through comparative analysis of keywords, sources, and authors. Structured literature search and eligibility evaluation was done using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. Peer-reviewed articles of 106 articles of 388 authors in the period of 2010–2025 were analysed and organized into four refined thematic clusters: (1) wettability enhancement of MgO-coated GNPs, (2) interface engineering, (3) fabrication and dispersion routes, and (4) biomedical applications. The evidence highlights their unique ability to enhance wettability, suppress detrimental interfacial reactions, and achieve strength–ductility synergy through semi‑coherent interfaces. Looking ahead, this review identifies new frontiers in adaptive interfaces, real‑time diagnostics, AI‑guided optimization, and multifunctional surface engineering, providing a roadmap for scalable and sustainable design of next‑generation MgO‑coated GNP reinforced AZ91 composites. • Profound systematic review consolidating advances in engineering of MgO-coated GNP/AZ91 composites. • Confirms that MgO coatings enable semi-coherent interfaces that achieve the rare strength-ductility synergy. • Provides consolidated foundation for future breakthroughs in new generation reinforced MgO@GNP/AZ91 composites. • Uniquely synthesizes advances in MgO@GNP/AZ91 wettability enhancement, interface engineering, and fabrication. • Identifies new frontiers in adaptive interfaces, AI-guided optimization and multifunctional surface engineering.