A better roadmap for designing novel bioactive glasses: effective approaches for the development of innovative revolutionary bioglasses for future biomedical applications

Opportunities for Bioactive Glass in Gastrointestinal Conditions: A Review of Production Methodologies, Morphology, Composition, and Performance

“…Most sol–gel BGs are silica-based. Their synthesis involves a well-established, chemistry-based methodology where components undergo hydrolysis and condensation reactions, generally at room temperature, forming a gel of nano- or microsized Si-based particles. ,,, This produces a “wet” product, which then undergoes drying and heat treatment stabilization, usually up to 600–700 °C depending on the intended morphology of the final product, to produce a glass, while avoiding crystallization of the silica network. ,,, …”

“…A more porous morphology is achieved by utilizing lower thermal treatment temperatures compared to melt-derived BGs . The degree of porosity and pore size are modifiable characteristics influenced by various experimental factors, such as precursors used, chemical composition and synthesis methodology (e.g., stirring speed/time and pH). ,,− To maintain an amorphous nanoporous structure, gels are heated to between 600 and 700 °C, depending on formulation constituents and synthesis methodology. , Similarly, characteristic morphological changes can be observed during drying, and thermal treatment parameters are altered depending on formulation constituents and methodology. When polymers or organic molecules have been incorporated as templates, lower temperatures within this spectrum are commonly used to create and maintain porous scaffold morphologies, while preventing crystallization or increased morphological density …”

“…2 Additive manufacturing techni- 1,2,28,29 This produces a "wet" product, which then undergoes drying and heat treatment stabilization, usually up to 600−700 °C depending on the intended morphology of the final product, to produce a glass, while avoiding crystallization of the silica network. 1,2,30,31 Precursor materials are commonly used in the initial hydrolysis and condensation reactions. This helps overcome reactivity and solubility difficulties associated with raw ingredients, which can prevent the synthesis reaction from proceeding.…”

“…2 The drying process removes water from the sol−gel, but due to its inherent porosity, −OH groups bonded to pore walls are not eliminated. 31,37 When thermally stabilized, oxygen atoms in the −OH groups can be incorporated into the silica network as Si−O−Si bonds, leaving some OH − groups and H + ions. 37 These H + ions act as network modifiers, reducing network connectivity and increasing the formulation's solubility.…”

“…2,37 Surface silica, hydroxyl, or silica-hydroxyl groups have been effectively used in BG formulations as active sites for functionalization and bonding, e.g., drug loading. 1,31,35 This fundamental difference alone clearly positions sol−gel-based formulations as a stronger synthesis platform for soft tissue BG applications (as seen in Table 2).…”