Mesoporous bioactive glasses (MBGs) exhibit a high surface area and a highly ordered mesoporous structure. MBGs have potential for both hard and soft tissue engineering applications. MBGs may be doped with biologically active ions to tailor their biological activity. Boron is being widely studied as a dopant of bioactive glasses. Recently, research has demonstrated the potential of boron-containing bioactive glasses for muscle regeneration. In this study, boron-containing MBGs, 10B-MBG and 18B-MBG nanoparticles, were produced by a microemulsion-assisted sol-gel approach for potential muscle regeneration applications. First, X-ray diffraction (XRD), Fourier transform infrared (FTIR), and energy-dispersive X-ray spectroscopy (EDX) analyses were conducted to study the chemical structure and composition of the nanoparticles. To examine the nanoparticle morphology, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images were analyzed. Both SEM images and particle size distribution determined by dynamic light scattering (DLS) indicated a decrease of the average particle size after boron doping. TEM images indicated a slit-shaped mesoporous structure of nanoparticles for all compositions. The ζ potential was measured, and a negative surface charge was found for all study groups due to the presence of silanol groups. Cytocompatibility and fluorescence microscopy studies were also carried out. The results indicated that low concentrations (0.1 and 1 mg mL^-1) of all MBG nanoparticles led to high viability of C2C12 cells. Fluorescence microscopy images indicated that at lower nanoparticle concentrations (0.1 and 1 mg mL^-1), C2C12 cells appeared to differentiate into myotubes, which was indicated by a spindle-shaped morphology. For 10 mg mL^-1 concentration of nanoparticles, C2C12 cells had a lower aspect ratio (estimated qualitatively by inspection of the images), which implied a lower degree of differentiation. Boron-doped MBG nanoparticles in reduced concentrations are suitable to induce differentiation of C2C12 cells into myotubes, indicating their potential for applications in muscle tissue repair.

Mesoporous bioactive glass nanoparticles (MBGNs) have gained relevance in bone tissue engineering, especially since they can be used as vectors for therapeutically active ions like zinc (Zn) or copper (Cu). In this study, the osteogenic properties of the ionic dissolution products (IDPs) of undoped MBGNs (composition in mol%: 70 SiO₂, 30 CaO) and MBGNs doped with 5 mol% of either Zn (5Zn-MBGNs) or Cu (5Cu-MBGNs; compositions in mol%: 70 SiO₂, 25 CaO, 5 ZnO/CuO) on human bone marrow-derived mesenchymal stromal cells were evaluated. Extracellular matrix (ECM) formation and calcification were assessed, as well as the IDPs’ influence on viability, cellular osteogenic differentiation and the expression of genes encoding for relevant members of the ECM. The IDPs of undoped MBGNs and 5Zn-MBGNs had a comparable influence on cell viability, while it was enhanced by IDPs of 5Cu-MBGNs compared to the other MBGNs. IDPs of 5Cu-MBGNs had slightly positive effects on ECM formation and calcification. 5Zn-MBGNs provided the most favorable pro-osteogenic properties since they increased not only cellular osteogenic differentiation and ECM-related gene expression but also ECM formation and calcification significantly. Future studies should analyze other relevant properties of MBGNs, such as their impact on angiogenesis.

In this work the influence of thermal treatment conditions on crystallization of a sol‐gel‐derived 45S5 bioactive glass was evaluated using DSC, XRD, TEM, EDX, and X‐ray nanocomputed tomography (nano‐CT). Temperature and time of the thermal treatment strongly influence the composition of the crystalline phases. At the onset of the glass transition temperature (600°C), combeite crystallizes as the main phase along with a calcium silicate‐phosphate phase, which decomposes into rhenanite from 2 hours of thermal treatment at this temperature. At the crystallization temperature (700°C), combeite remains as the main crystalline phase. Additionally, Na ₂ Ca ₂ Si ₂ O ₇ crystalline phase is formed. Our results provide a basic platform for tailoring the crystalline phases by controlling the nucleation and growth of crystalline phases via thermal treatments. Different morphologies (round particles, stacked layers, toothpick‐like, and long features) were discerned by TEM as a function of temperature and time of treatment. It is the first time that bioactive glass is investigated by nano‐CT at laboratory scale. This novel technique enables the 3D visualization of features in the nanometer range, giving clear information about the volumetric distribution of phases in the sample.

In this study, as a measure to enhance the antimicrobial activity of biomaterials, the selenium ions have been substituted into hydroxyapatite (HA) at different concentration levels. To balance the potential cytotoxic effects of selenite ions (SeO₃²⁻) in HA, strontium (Sr²⁺) was co-substituted at the same concentration. Selenium and strontium-substituted hydroxyapatites (Se-Sr-HA) at equal molar ratios of x Se/(Se + P) and x Sr/(Sr + Ca) at (x = 0, 0.01, 0.03, 0.05, 0.1, and 0.2) were synthesized via the wet precipitation route and sintered at 900 °C. The effect of the two-ion concentration on morphology, surface charge, composition, antibacterial ability, and cell viability were studied. X-ray diffraction verified the phase purity and confirmed the substitution of selenium and strontium ions. Acellular in vitro bioactivity tests revealed that Se-Sr-HA was highly bioactive compared to pure HA. Se-Sr-HA samples showed excellent antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus carnosus) bacterial strains. In vitro cell–material interaction, using human osteosarcoma cells MG-63 studied by WST-8 assay, showed that Se-HA has a cytotoxic effect; however, the co-substitution of strontium in Se-HA offsets the negative impact of selenium and enhanced the biological properties of HA. Hence, the prepared samples are a suitable choice for antibacterial coatings and bone filler applications.

In this study, multifunctional stratified antibacterial and bioactive coatings were deposited and characterised. Initially, PEEK/bioactive glass (BG)/ mesoporous bioactive glass nanoparticle (MBGN) layers with a thickness of 110–120 μm were deposited on stainless steel substrates using electrophoretic deposition (EPD). Thin silver nanocluster-silica composite layers with a thickness of 70–155 nm were then deposited by radio frequency (RF) co-sputtering on the previously deposited EPD coatings. The deposition was carried for two different sputtering times (20 min and 40 min), which led to different layer thicknesses. PEEK/BG/MBGNs coatings were also deposited via single-step EPD. A comparison between the physicomechanical and biological characteristics of single layer PEEK/BG/MBGNs composite coating and bilayer Ag-PEEK/BG/MBGNs is presented. Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) indicated that silver nanoclusters were homogeneously distributed in the multilayered EPD/RF coatings. An apatite-like structure was formed on the surface of the coatings upon immersion in simulated body fluid (SBF) after 1 day. Silver nanoclusters embedded in the silica matrix as a top layer provided controlled release of silver ions which led to a potent antibacterial effect against E. coli and S. carnosus. Single layer coatings exhibited a burst release of Ag ions, which led to antibacterial effects but were toxic to osteoblast cells. Finally, the results of WST-8 assays confirmed that the multi-structured coatings allow osteoblast-like cells to proliferate and attach strongly on the surface of the coatings.