In vitro behaviour of osteoblast cells seeded into a COL/β-TCP composite scaffold

Collagen/Beta-Tricalcium Phosphate Based Synthetic Bone Grafts via Dehydrothermal Processing

Millions of patients worldwide remain inadequately treated for bone defects related to factors such as disease or trauma. The drawbacks of metallic implant and autograft/allograft use have steered therapeutic approaches towards tissue engineering solutions involving tissue regeneration scaffolds. This study proposes a composite scaffold with properties tailored to address the macro- and microenvironmental conditions deemed necessary for successful regeneration of bone in defect areas. The biodegradable scaffold composed of porous beta-tricalcium phosphate particles and collagen type I fibers is prepared from a mixture of collagen type-I and β-tricalcium phosphate (β-TCP) particles via lyophilization, followed by dehydrothermal (DHT) processing. The effects of both sterilization via gamma radiation and the use of DHT processing to achieve cross-linking were investigated. The impact of the chosen fabrication methods on scaffold microstructure and β-TCP particle-collagen fiber combinations were analyzed using X-ray diffractometry (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and microcomputerized tomography (µ-CT). Electron spinning resonance (ESR) analysis was used to investigate free radicals formation following sterilization. Results revealed that the highly porous (65% porosity at an average of 100 µm pore size), mechanically adequate, and biocompatible scaffolds can be utilized for bone defect repairs.

Evaluation of pristine and Eu ₂O₃-added MgB ₂ ceramics for medical applications: hardness, corrosion resistance, cytotoxicity and antibacterial activity

Nano- or micropowders of Eu2O3 were added to MgB2, resulting in a composition of (MgB2)0.975(EuO1.5)0.025. Pristine and doped samples were prepared using spark plasma sintering and tested for (i) Vickers hardness, (ii) pH evolution in phosphate-buffered saline solution, (iii) corrosion resistance (Tafel polarization curves), (iv) cytotoxicity (in vitro tests), and (v) antibacterial activity. Eu2O3 addition influenced the investigated properties. Solutions of MgB2-based samples show a relatively high saturation pH of 8.5. This value is lower than that of solutions incubated with Mg or other Mg-based biodegradable alloys reported in the literature. MgB2-based samples have lower electro-corrosion rates than Mg. Their Vickers hardness is 6.8-10.2GPa, and these values are higher than those of biodegradable Mg-based alloys. MgB2 has low in vitro biocompatibility, good antibacterial activity against Escherichia coli, and mild activity against Staphylococcus aureus. Our results suggest that MgB2-based materials deserve attention in biomedical applications, such as implants or sterile medical instruments.

Magnesium substitution effect on porous scaffolds for bone repair

Of great interest in developing artificial bone is the incorporation of magnesium (Mg) ions into the ceramic lattice in order to improve the physico-chemical and structural properties of the material and to increase its morphological affinity towards newly formed osseous tissue. In the present study, we evaluated the morphological and biological properties of composite scaffolds fabricated by mixing a nanopowder of Mg-substituted beta-tricalcium phosphate with collagen type I in two dry weight ratios (variant I and II). We used biochemical methods, and electron and light microscopy to investigate their porosity, biodegradability and morphology. Osteoblast cell culture behavior in the presence of nanocomposite variants was also examined. Variant I scaffold presented a higher percentage of cross-links and a better resistance to collagenase degradation compared to variant II scaffold. Their porosity did not vary significantly. Osteoblasts cultivated in the presence of nanocomposite scaffolds for 72 h exhibited good cell viability and a normal morphology. When osteoblasts were injected into the scaffolds, a slightly higher proportion of adhered cells were observed for Mg-substituted samples after 7 days of cultivation. All these results showed that Mg-containing porous composite scaffolds had controlled degradation, allowed osteoblast proliferation and adhesion and are good candidates for bone repair.