Recent advances in cobalt-based alloy and nano bioactive glass composites: Synthesis, characterization, and biomedical applications

Abstract

Cobalt-based alloys and bioactive glasses are known as biomaterials used for orthopedic and dental applications because of their mechanical and biological properties. Due to the acceptable mechanical strength, fatigue resistance, and corrosion stability of cobalt-based alloys in physiological environments, these metallic alloys are suitable for load-bearing implants. However, they have faced some limitations in osseointegration and biological performance because of their high elastic modulus, limited bioactivity, and concerns about metallic ion release in long-term use. In contrast, nano bioactive glasses (nBGs) have shown excellent bioactivity, osteogenic potential, angiogenesis and antibacterial responses through surface reactivity and controlled ion release, but their brittleness and low fracture toughness limited their load-bearing application. This review provides an overview of recent advances in cobalt-based alloy/nano bioactive glass composites as a multi-component system which is designed to overcome the limitations of single-phase systems. The structural, mechanical, and chemical properties of cobalt-based alloys and nBGs are discussed, followed by the synergistic effects achieved at the metal–glass interface. Several synthesis and compositional strategies, such as melt-derived, sol–gel processing, powder metallurgy, additive manufacturing and surface coating techniques have been explored. The in vitro biological performance of these composites, including cytocompatibility, osteogenic differentiation, angiogenic stimulation, and antimicrobial activity, is discuss in relation to their potential applications in orthopedic and dental implants. Finally, key challenges such as mechanical compatibility, long-term stability, cobalt-related regulatory concerns, and future research directions are outlined.