Synthesis, characterization and in vitro study of magnetic biphasic calcium sulfate-bioactive glass

Enhancement in the induction heating efficacy of sol-gel derived SiO2-CaO-Na2O-P2O5 bioglass-ceramics by incorporating magnetite nanoparticles

Magnetite (Fe3O4) nanoparticle (MNP)-substituted glass-ceramic (MSGC) powders with compositions of (45 - x)SiO2-24.5CaO-24.5Na2O-6P2O5-xFe3O4 (x = 5, 8, and 10 wt%) have been prepared by a sol-gel route by introducing Fe3O4 nanoparticles during the synthesis. The X-ray diffraction patterns of the as-prepared MSGC nanopowders revealed the presence of combeite (Na2Ca2Si3O9), magnetite, and sodium nitrate (NaNO3) crystalline phases. Heat-treatment up to 700 °C for 1 h resulted in the complete dissolution of NaNO3 along with partial conversion of magnetite into hematite (α-Fe2O3). Optimal heat-treatment of the MSGC powders at 550 °C for 1 h yielded the highest relative percentage of magnetite (without hematite) with some residual NaNO3. The saturation magnetization and heat generation capacity of the MSGC fluids increased with an increase in the MNP content. The in vitro bioactivity of the MSGC pellets was evaluated by monitoring the pH and the formation of a hydroxyapatite surface layer upon immersion in modified simulated body fluid. Proliferation of MG-63 osteoblast cells indicated that all of the MSGC compositions were non-toxic and MSGC with 10 wt% MNPs exhibited extraordinarily high cell viability. The MSGC with 10 wt% MNPs demonstrated optimal characteristics in terms of cell viability, magnetic properties, and induction heating capacity, which surpass those of the commercial magnetic fluid FluidMag-CT employed in hyperthermia treatment.

Synthesis, Characterization, and in Vitro Biological Evaluation of Copper-Containing Magnetic Bioactive Glasses for Hyperthermia in Bone Defect Treatment

Hyperthermia treatment induced by magnetic mesoporous glasses has been applied as a potential therapeutic approach for bone defects due to malignant tumors. The objective of this study was to synthesize and characterize the structural and biological properties of magnetic bioactive glasses (BGs) for producing multifunctional materials. The effect of the addition of copper (Cu) to the bioactive glass composition was also evaluated. Fe BG and FeCu BG as magnetic mesoporous BGs, and Cu BG as mesoporous BG were synthesized and dried by template sol-gel method. Then the synthesized bioglasses were characterized and analyzed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive electron disperse spectroscopy (EDS), Brunauer-Emmett-Teller (BET), and vibrating sample magnetometer (VSM). In addition, the antibacterial behavior, cytotoxicity assay (MTT test), proliferation assay of HUVEC cell assay, and bioactivity (ALP activity test) of the synthesized BGs were evaluated. The characterization results exhibited that the synthesized powders formed mesoporous glasses with nanoparticle morphology, good surface area, and magnetic properties. The synthesized BGs also demonstrated suitable biological behavior. The magnetic saturation of bioactive glasses was increased by the addition of copper oxide. A two-phase structure was observed for the magnetic glasses compared to the copper-containing glasses, thus making them suitable for drug delivery systems. The antibacterial behavior was found to be better for the Cu BG and Fe BG compared to the FeCu BG. However, the least amount of cytotoxicity was observed for the Fe BG and FeCu BG, compared to the Cu BG. In addition, the Fe-containing BGs compared with the control group showed a lack of HUVEC cell proliferation and angiogenesis motivation. From the ALP assay, higher bioactivity for the magnetic bioglasses in the presence of mesenchymal cells was found. From the results of this in vitro study, the Cu-containing magnetic bioglass (FeCu BG) could be considered as a new generation of magnetic glasses for inducing hyperthermia in treatment of bone defects due to malignant tumors. However, further in vitro and in vivo studies are required to confirm their applications in healing of bone defects and tissue engineering.

Iron doped β-Tricalcium phosphate: Synthesis, characterization, hyperthermia effect, biocompatibility and mechanical evaluation

The ability of β-Tricalcium phosphate [β-TCP, β-Ca₃(PO₄)₂] to host iron at its structural lattice and its associated magnetic susceptibility, hyperthermia effect, biocompatibility and mechanical characteristics is investigated. The studies revealed the ability of β-Ca₃(PO₄)₂ to host 5.02mol% of Fe³⁺ at its Ca²⁺(5) site. Excess Fe³⁺ additions led to the formation of trigonal Ca₉Fe(PO₄)₇ and moreover a minor amount of CaFe₃(PO₄)₃O crystallization was also observed. A gradual increment in the iron content at β-Ca₃(PO₄)₂ results in the simultaneous effect of pronounced hyperthermia effect and mechanical stability. However, the presence of CaFe₃(PO₄)₃O contributes for the reduced hyperthermia effect and mechanical stability of iron substituted β-Ca₃(PO₄)₂. Haemolytic tests, cytotoxicity tests and ALP gene expression analysis confirmed the biocompatibility of the investigated systems.