Ion substitution in bioactive glass: A comprehensive review of structural modifications and functional effects

Bioactive glass (BG), a pioneering material in the field of biomaterials, has demonstrated significant potential for therapeutic applications such as bone regeneration and drug delivery. These effects are achieved through structural modifications that involve the incorporation of ions into the silica network, enabling controllable applications. This review aims to provide a comprehensive overview of the effects of ion substitution on the silica network of BG, focusing on silver (Ag), strontium (Sr), magnesium (Mg), lithium (Li), zinc (Zn), and copper (Cu). Through an extensive examination of recent literature, we investigated the primary effects of ion substitution on the glass structure, including change to its physical properties, impacts on pH and surface characteristics, and functional effects. The reports approved that ion substitution significantly alters fundamental parameters of the silica network, including thermal properties, porosity, swelling, and degradation. Each ion imparts distinct effects on the glass structure, bioactivity, and functional properties such as antibacterial activity, cell viability, osteogenesis, and angiogenesis. Notably, these effects are often dose-dependent and ion-specific. The review emphasizes that ion substitution is an effective strategy for producing high-quality BG with tailored properties. Understanding the specific effects of each ion facilitates the development of BG systems with controlled release and surface interactions, opening up new possibilities for various biomedical applications. This comprehensive overview provides valuable insights for researchers and practitioners in the field, paving the way for future advancements in BG design and application.