Effect of Modification of Mesoporous Bioactive Glass with Cucurbit[n]urils (n = 6, 7, 8) on the Structural and Physicochemical Characteristics of Composite Biomaterials

The surface functionalization of mesoporous bioactive glasses (MBGs) is of critical importance for the development of advanced hybrid biomaterials with controlled interfacial and adsorption properties. Composite systems based on MBGs modified with cucurbit[n]urils (CB[6], CB[7], and CB[8]) were synthesized and systematically investigated to elucidate size-dependent interaction mechanisms and their influence on textural and physicochemical characteristics. Functionalization was achieved via aqueous deposition followed by controlled thermal treatment. Nitrogen sorption analysis revealed distinct pore modification behaviors: CB[6] reduced the specific surface area by 64% with partial pore occupation; CB[7] induced extensive mesopore occlusion (92.4% surface area reduction); whereas CB[8] produced a balanced decrease (71.2%) while largely preserving microporosity. Thermogravimetric analysis demonstrated comparable loading for CB[7] and CB[8], yet MBGs@CB[8] exhibited enhanced thermal stability, with the DTG maximum shifted to ~395 °C. Molecular modeling supported these findings, indicating the lowest adsorption energy for CB[8]. This combination of structural preservation and enhanced stability provides the most favorable balance between pore accessibility and structural modification, demonstrating strong potential as a versatile modifier for subsequent functionalization, including drug loading applications in bone-regenerative systems.