Nanoparticle Architecture Governing Antibacterial and Osteoinductive Responses in Bone-Integrating Implants

Metallic nanoparticles (MNPs) have emerged as leading candidates in biomedical applications owing to their unique physicochemical properties and dual functionality, combining potent bactericidal and osteoinductive effects. These bioactivities are intricately governed by structural parameters such as size, shape, crystallinity, and chemical composition, which collectively dictate their interactions with biological systems. These interactions affect key mechanisms including oxidative stress induction, membrane disruption, and modulation of cellular signaling pathways. Despite considerable progress, a comprehensive understanding of the structure property–activity-specific structural relationship in MNPs remains incomplete, hindering the rational design of optimized nanomaterials. This review critically examines recent advances in elucidating the bactericidal and osteoinductive mechanisms of MNPs, with a particular focus on the role of structural determinants. Furthermore, current challenges and future directions for tailoring nanoparticle architecture to enhance clinical performance are discussed. To address this, we conducted a systematic review of the literature published between 2005 and 2024 using Web and Web of Science direct and Scopus databases. Our analysis is structured around a structure →mechanism→outcome perspective, linking nanoparticle features to biological responses. Key insights include the following: (i) nanoparticles below ~20 nm generally enhance bacterial efficiency through enhanced membrane disruption; (ii) surface hydroxyl density above critical thresholds promotes osteogenic signaling; and (iii) safe concentration windows remain narrow, highlighting the importance of dose optimization. We conclude by discussing the translational challenges and future directions for tailoring nanoparticle architectures to advance clinical applications.