A Structural Comparison of Ordered and Non-Ordered Ion Doped Silicate Bioactive Glasses

Engineering mesoporous bioactive glasses for emerging stimuli-responsive drug delivery and theranostic applications

Mesoporous bioactive glasses (MBGs), which belong to the category of modern porous nanomaterials, have garnered significant attention due to their impressive biological activities, appealing physicochemical properties, and desirable morphological features. They hold immense potential for utilization in diverse fields, including adsorption, separation, catalysis, bioengineering, and medicine. Despite possessing interior porous structures, excellent morphological characteristics, and superior biocompatibility, primitive MBGs face challenges related to weak encapsulation efficiency, drug loading, and mechanical strength when applied in biomedical fields. It is important to note that the advantageous attributes of MBGs can be effectively preserved by incorporating supramolecular assemblies, miscellaneous metal species, and their conjugates into the material surfaces or intrinsic mesoporous networks. The innovative advancements in these modified colloidal inorganic nanocarriers inspire researchers to explore novel applications, such as stimuli-responsive drug delivery, with exceptional in-vivo performances. In view of the above, we outline the fabrication process of calcium-silicon-phosphorus based MBGs, followed by discussions on their significant progress in various engineered strategies involving surface functionalization, nanostructures, and network modification. Furthermore, we emphasize the recent advancements in the textural and physicochemical properties of MBGs, along with their theranostic potentials in multiple cancerous and non-cancerous diseases. Lastly, we recapitulate compelling viewpoints, with specific considerations given from bench to bedside.

Bioactive Bilayer Glass Coating on Porous Titanium Substrates with Enhanced Biofunctional and Tribomechanical Behavior

The use of porous titanium samples fabricated by space-holder powder metallurgy with bioactive coatings has already been reported to prevent resorption of the bone surrounding the implant and improve osseointegration, respectively. However, the presence of pores as well as the poor adherence and the brittle behavior inherent to glassy coatings affect the service behavior of implants fabricated from these samples. Therefore, they need to be optimized. In this work, 50 vol.% of porosity titanium substrates were manufactured with different pore range size (100–200 and 355–500 µm) spacer particles and coated with a bilayer of bioactive glasses (45S5/1393). The effect of the pores on the tribomechanical properties and infiltration of the bioactive glass 1393 along with the bioactivity of the bioactive glass 45S5 were evaluated by instrumented micro-indentation and scratch tests and the formation of hydroxyapatite in simulated body fluid. The results obtained were very promising as potential implants for the replacement of small tumors in cortical bone tissues, mainly due to the smaller pores that present an improved biomechanical and biofunctional balance.