Upsorn Boonyang

The repair of critical bone defects remains a substantial clinical challenge. A regenerative material must support osteogenesis, provide appropriate mechanical function, and degrade at a rate compatible with tissue formation. Hydroxyapatite (HA) is osteoconductive and chemically similar to bone mineral, but its brittleness and slow resorption limit its use as a stand-alone load-bearing material. Silsesquioxanes, particularly polyhedral oligomeric silsesquioxanes (POSS), provide molecularly defined silicon–oxygen frameworks with modifiable organic substituents. These can be incorporated as fillers or covalent network components. This review critically evaluates silsesquioxane-based biomaterials for bone regeneration. It distinguishes direct evidence from HA-containing systems from mechanistic analogues. These analogues include silicate-substituted HA, bioactive glass, dental POSS composites, and related polymer–POSS materials. Sol–gel processing, in situ mineralisation, particle incorporation, surface grafting, and network formation are assessed in relation to interfacial bonding, apatite nucleation, mechanical behaviour, and degradation. Current evidence indicates that reinforcement depends on cage functionality, dispersion, loading, matrix chemistry, and interfacial integration. Direct evidence that implanted HA–POSS systems release orthosilicic acid at biologically active concentrations remains unavailable. Cross-system comparisons further show that reported mechanical values cannot be ranked without accounting for physical form, porosity, test mode, and environmental conditions. The principal translational barriers are (i) the scarcity of load-bearing in vivo studies, (ii) uncertain degradation-product fate, and (iii) sterilisation sensitivity in some POSS-modified polymers. Further barriers are (iv) limited manufacturing standardisation and (v) the absence of clinically validated HA–POSS implants. The most defensible rationale for these hybrids is therefore their capacity for multifunctional interfacial design rather than universal mechanical superiority.

Downsized materials of iron( iii ) spin crossover complexes are reported, with small decreases in hysteresis widths, but no significant change in the abruptness of spin crossover.

Bioactive glass ceramics (BGCs) have been used in orthopedic and dentistry due to having better osteoconductive and osteostimulative properties. This study aimed to evaluate and compare the drug release properties of two different BGCs; 45S5 and S53P4. The BGCs were composed with four phases of SiO2 – CaO – Na2O – P2O5 system, synthesized by sol–gel method using dual templates; a block-copolymer as mesoporous templates and polymer colloidal crystals as macroporous templates, called three-dimensionally ordered macroporous-mesoporous bioactive glass ceramics (3DOM-MBGCs). In vitro bioactivity test performed by soaking the 3DOM-MBGCs in simulated body fluid (SBF) at 37°C. The results indicated that, the 45S5 have the ability to grow hydroxyapatite-like layer on the surfaces faster than S53P4. Gentamicin drug was used to examine in vitro drug release properties in phosphate buffer solution (PBS). The amount of drug release was quantified through UV/Vis spectroscopy by using o-phthaldialdehyde reagent. S53P4 showed high drug loading content. The outcome of drug release in PBS showed that both S53P4 and 45S5 exhibited a slowly continuous gentamicin release. The resultant drug release profiles were fitted to the Peppas-Korsmeyer model to establish the predominant drug release mechanisms, which revealed that the kinetics of drug release from the glasses mostly dominated by Fickian diffusion mechanism.

The quaternary phase bioactive glasses (SiO₂-CaO-Na₂O-P₂O₅) were synthesized by the sol-gel process. Pluronic P123, using surfactant as structure-directing agents as well as phase separation inducers. The obtained bioactive glasses were characterized regarding morphology by using the scanning electron microscopy (SEM). Polymer colloidal crystals (CCTs) as the template component yielded either three-dimensionally ordered macroporous (3DOM) structure or hollow spheres shaped bioactive glass. The other type of morphology generation is related to the polymerization-induced phase separation (PIPS) in the gelation process. The heterogeneous precursor i.e. silica-rich regions caused the microspheres and solvent-rich areas produced micrometer-scale void space in bicontinuos structure. While the lower pH of starting precursor in 45S4P showed stronger precursor-template interactions than the 53S4P by generating the completely hollow spheres structure.

Fluoro/hydroxyapatite (FHAp) were prepared by hydrothermal at 150 °C for 24 hours with different of starting materials. The conversion of hydroxyapatite (HAp) and tricalcium phosphate to FHAp showed the rod-like shape with 200 nm. While, the morphology of FHAp from crocodile eggshell as CaCO₃ form with different in phosphorus and fluoride source showed the unique structure evolution from rod-like hexagonal crystals, dumbbell to ball shape. Two distinctive morphology, first when using NaF as fluoride source with (NH₄)₂HPO₄ precursor show the large cubic structure in high magnification it is tufted hexagonal crystal and it bundle like structure. As the pH value decreases in NH₄F, it increases crystal size. For H₃PO₄ as phosphate precursor found that unique structure evolution from rod-like hexagonal crystals to dumbbell structure and then form the sphere assembly with a size of several micrometers.