A 3D macroporous and magnetic Mg2SiO4-CuFe2O4 scaffold for bone tissue regeneration: Surface modification, in vitro and in vivo studies.

Macroporous scaffolds with bioactivity and magnetic properties can be a good candidate for bone regeneration and hyperthermia. In addition, modifying the surface of the scaffolds with biocompatible materials can increase their potential for in vivo applications. Here, we developed a multifunctional nanocomposite Mg2SiO4-CuFe2O4 scaffold for bone regeneration and hyperthermia. The surface of scaffold was coated with various concentrations of poly-3-hydroxybutyrate (P3HB, 1-5% (w/v)). It was observed that 3% (w/v) of P3HB provided a favorable combination of porosity (79 ± 2.1%) and compressive strength (3.2 ± 0.11 MPa). The hyperthermia potential of samples was assessed in the presence of various magnetic fields in vitro. The coated scaffolds showed a lower degradation rate than the un-coated one up to 35 days of soaking in simulated biological medium. Due to the porous and specific morphology of P3HB, it was found that in vitro bioactivity and cell attachment were increased on the scaffold. Moreover, it was observed that the P3HB coating improved the cell viability, alkaline phosphatase activity, and mineralization of the scaffold. Finally, we studied the bone formation ability of the scaffolds in vivo, and implanted the developed scaffold in the rat's femur for 8 weeks. Micro-computed tomography results including bone volume fraction and trabecular thickness exhibited an improvement in the bone regeneration of the coated scaffold compared to the control. The overall results of this study introduce a highly macroporous scaffold with multifunctional performance, noticeable ability in bone regeneration, and hyperthermia properties for osteosarcoma.

On the Bioactivity and Mechanical Properties of Gehlenite Nanobioceramic: A Comparative Study.

BACKGROUND: For a new biomaterial which is going to be applied in bone tissue regeneration, bioactivity (bone bonding ability) and desirable mechanical properties are very essential parameters to take into consideration. In the present study, the gehlenite's mechanical properties and bioactivity are assessed and compared with hydroxyapatite (HA) for bone tissue regeneration. METHOD: Gehlenite and HA nanoparticles are synthesized through sol-gel method and coprecipitation technique, respectively, and their physical and chemical properties are characterized through X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy. RESULTS: The results prove that the gehlenite and HA phases without any undesirable phase are obtained, and the particles of both compounds are in the nanometer range with spherical morphology. The compressive strength of both compounds are assessed, and the values for gehlenite and HA disks are 144 ± 5 and 150 ± 4.8 MPa, respectively. Next, their bioactivity potential is assessed into simulated body fluid (SBF) up to 21 days, and the results show that after 14 days, gehlenite disk's surface is completely covered with newly formed Ca-P particles. However, some sporadic precipitations after 21 days soaking into SBF are formed onto the HA disk's surface. CONCLUSION: This comparative study shows that nanostructured gehlenite disk with desirable mechanical properties and faster bioactivity kinetic than HA can be considered as a promising bioceramic for bone tissue regeneration.

Hierarchical porous Mg2SiO4-CoFe2O4 nanomagnetic scaffold for bone cancer therapy and regeneration: Surface modification and in vitro studies.

3D multifunctional bone scaffolds have recently attracted more attention in bone tissue engineering because of addressing critical issues like bone cancer and inflammation beside bone regeneration. In this study, a 3D bone scaffold is fabricated from Mg2SiO4-CoFe2O4 nanocomposite which is synthesized via a two-step synthesis strategy and then the scaffold's surface is modified with poly-3-hydroxybutyrate (P3HB)-ordered mesoporous magnesium silicate (OMMS) composite to improve its physicochemical and biological properties. The Mg2SiO4-CoFe2O4 scaffold is fabricated through polymer sponge technique and the scaffold exhibits an interconnected porous structure in the range of 100-600 µm. The scaffold is then coated with OMMS/P3HB composite via dip coating and the physical, chemical, and biological-related properties of OMMS/P3HB composite-coated scaffold are assessed and compared to the non-coated and P3HB-coated scaffolds in vitro. It is found that, on the one hand, P3HB increases the cell attachment, proliferation, and compressive strength of the scaffold, but on the other hand, it weakens the bioactivity kinetic. Addition of OMMS to the coating composition is accompanied with significant increase in bioactivity kinetic. Besides, OMMS/P3HB composite-coated scaffold exhibits higher drug loading capacity and more controlled release manner up to 240 h than the other samples because of OMMS which has a high surface area and ordered mesoporous structure suitable for controlled release applications. The overall results indicate that OMMS/P3HB coating on Mg2SiO4-CoFe2O4 scaffold leads to a great improvement in bioactivity, drug delivery potential, compressive strength, cell viability, and proliferation. Moreover, OMMS/P3HB composite-coated scaffold has heat generation capability for hyperthermia-based bone cancer therapy and so it is suggested as a multifunctional scaffold with great potentials for bone cancer therapy and regeneration.

Nanostructured magnetic Mg2SiO4-CoFe2O4 composite scaffold with multiple capabilities for bone tissue regeneration.

Multifunctional magnetic 3D scaffolds are recently of particular interest because of their applications in hyperthermia-based therapy and localized drug delivery beside of their basic properties to be applied in bone tissue regeneration. In the current study, a magnetic nanocomposite is designed and synthesized through a two-step synthesis strategy in which CoFe2O4 nanoparticles are prepared via sol-gel combustion method and then they are coated through sol-gel method with Mg2SiO4. The characterization relates to the nanocomposite shows that Mg2SiO4-CoFe2O4 is successfully synthesized and it has a core-shell structure. Then, 3D scaffolds are fabricated through polymer sponge technique from the nanocomposite. Physiochemical and biological properties of the scaffolds are assessed in vitro amongst which bioactivity, biodegradability, mechanical properties, hyperthermia capability, controlled release potential, antibacterial activity, cell compatibility and attachment can be mentioned. The results demonstrate that the scaffolds have high porous structure with interconnected porosity and desirable mechanical properties close to cancellous bone. The magnetic scaffold is biodegradable and bioactive and exhibits controlled release of rifampin as an antibiotic drug up to 96 h. Moreover, in the exposure of different magnetic fields it has potential to produce heat for different kinds of hyperthermia-based therapies. The antibacterial activity of drug-loaded scaffold is assessed against S. aureus bacteria. The results suggest that Mg2SiO4-CoFe2O4 nanocomposite scaffold with multiple capabilities has a great potential to be applied in the case of large bone defects which are caused by tumors to not only eradicate remained cancerous tissues, but also prevent infection after surgery and regenerate bone defect.