Bone Regeneration in Rat Using a PCL/gelatin/Nanoclay Nanocomposite Scaffold Containing Silybin

Bone cells need solid structures like the extracellular matrix (ECM) for healing injured areas. Finding appropriate materials and fabrication processes for the scaffold is a challenge in tissue engineering. In this study, 3-D porous scaffold was made of Polycaprolactone/Gelatin/Nanoclay (PCL/GNF/NC) and different dosages of silybin (Sil) were loaded by a combination of electrospinning and thermal-induced phase separation (TIPS) techniques. Different experiments like assessing surface morphology, porosity, compressive strength, water contact angle, degradation rate, releasing profile, hemolysis, and cell proliferation were done to assess attributes of fabricated scaffolds. For in vivo evaluation, the calvaria defect model in rats was used and the result was evaluated by histological analysis. Based on the results, the porosity of scaffolds was in the range of 70-90%, and samples containing silybin had lower compress strength and contact angle and higher degradation rate in comparison with samples without silybin. The results showed that PCL/GNF/NC/Sil1% had better cell proliferation bone healing than other studied groups. The results of this study can be considered for further researches to assess the effect of silybin in bone defect treatment.

Porous Carbonated Hydroxyapatite-Based Paraffin Wax Nanocomposite Scaffold for Bone Tissue Engineering: A Physicochemical Properties and Cell Viability Assay Analysis

Porosity is one of the parameters of scaffold pore structure that must be developed using paraffin wax as a synthetic polymer for making porous bioceramics carbonated hydroxyapatite (CHA). This study fabricated CHA based on abalone mussel shells (Halioitis asinina); CHA/paraffin wax nanocomposite scaffolds were synthesized using paraffin wax with concentration variations of 10, 20, and 30 wt.%. The energy-dispersive X-ray spectroscopy (EDS) results showed that the Ca/P molar ratio of CHA was 1.72, which approaches the natural bone. The addition of paraffin wax in all concentration variation treatments caused the crystallographic properties of the CHA/paraffin wax nanocomposite scaffolds to decrease. The results of pore analysis suggest that the high concentration of paraffin wax in the CHA suspension is involved in the formation of more pores on the surface of the scaffold, but only CHA/paraffin wax 30 wt.% had a scaffold with potential to be used in media with a cellular growth orientation. The micropore analysis was also supported by the cell viability assay results for CHA/paraffin wax 30 wt.% nanocomposite scaffold, where serial doses of scaffold concentrations to mouse osteoblast cells were secure. Overall, based on this analysis, the CHA/paraffin wax scaffold can be a candidate for bone tissue engineering.

Repair of Osteoporotic Bone Defects Using Adipose-Derived Stromal Cells and Umbilical Vein Endothelial Cells Seeded in Chitosan/Nanohydroxyapatite-P24 Nanocomposite Scaffolds

Background. The cell regeneration and blood supply of bone defect lesions are restricted under osteoporotic pathological conditions, which make the healing of bone defect of osteoporosis still a great challenge. The current therapeutic strategies that mainly inhibit bone resorption are not always satisfactory for osteoporotic bone defects, which make the development of new therapies an urgent need. Methods. Previously, we prepared chitosan/nanohydroxyapatite (CS/nHA) biomimetic nanocomposite scaffolds for controlled delivery of bone morphogenetic protein 2-derived peptide (P24). In this study, we determined the effect of coculturing adipose-derived stromal cells (ADSCs) and human umbilical vein endothelial cells (HUVECs) with the CS-P24/nHA nanocomposite scaffolds on osteoporotic bone defect healing. In vitro mixed coculture models were employed to assess the direct effects of coculture. Results. ADSCs cocultured with HUVECs showed significantly greater osteogenic differentiation and mineralization compared with ADSCs or HUVECs alone. The CS-P24/nHA scaffold cocultured with ADSCs and HUVECs was more effective in inducing osteoporotic bone repair, as demonstrated by micro-computed tomography and histology of critical-sized calvariae defects in ovariectomized rats. Calvariae defects treated with the CS-P24/nHA nanocomposite scaffold plus ADSC/HUVEC coculture had a greater area of repair and better reconstitution of osseous structures compared with defects treated with the scaffold plus ADSCs or the scaffold plus HUVECs after 4 and 8 weeks. Conclusion. Taken together, coculture of ADSCs and HUVECs with the CS-P24/nHA nanocomposite scaffold is an effective combination to repair osteoporotic bone defects.