Poly(1,8-octanediol citrate)/bioactive glass composite with improved mechanical performance and bioactivity for bone regeneration

Poly（1,8-octanediol-co-citrate） （POC） represents a new promising biocompatible and biodegradable polyester that has been extensively investigated for soft tissue engineering. However, the poor mechanical performance and poor bioactivity limit its application in bone regeneration. In this study, a series of POC/bioactive glasses （BG） composites were developed using 45S5 Bioglass^Θ and a phytic acid- derived bioactive glass （referred as PSC）. The results indicated that calcium in BG could enhance the crosslinking of the POC/BG composites by forming calcium dicarboxylate bridges and thus improve their mechanical performances. When PSC were used, the composites exhibited significantly better mechanical properties compared to composites with 45S5 Bioglass^Θ. For example, by incorporating 70wt% PSC, the compressive strength of POC/PSC composites could be improved to approximately 50 MPa and modulus 1.3-h 0.1 GPa. Furthermore, all these POC/PSC composites showed good in vitro bioactivity and cellular biocompatibility. Histology results in femoral condyle defects of Sprague-Dawley rats indicated that the POC/PSC samples integrated well with surrounding tissues and stimulated bone regeneration. The improved mechanical properties and bioactivity of POC/PSC composites make them promising for potential application in bone regeneration.

Effect of Porous Activated Charcoal Reinforcement on Mechanical and In-Vitro Biological Properties of Polyvinyl Alcohol Composite Scaffolds

The present work focused on developing an innovative composite material by reinforcing polymer matrix with highly porous activated charcoal. Polyvinyl alcohol-activated charcoal（PVA-AC） composite scaffolds were developed by varying the AC concentrations（0, 0.5, 1, 1.5, 2 and 2.5 wt%） in PVA matrix by freeze drying method. The developed scaffolds were characterized for their physicochemical, mechanical and in-vitro biological properties. In addition, the effect of AC on the attachment, proliferation and differentiation of osteoblast MG 63 cells was evaluated by scanning electron microscopy（SEM）, 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide（MTT） assay, alkaline phosphatase（ALP） activity assay and alizarin red stain-based（ARS） assay. All the PVA-AC composite scaffolds exhibited good bioactivity, hemocompatibility and protein adsorption properties. The scaffolds with high AC concentration（2.5 wt%） showed controlled drug release kinetics that are suitable for long term healing. The mechanical properties of all the PVA-AC composite scaffolds were improved when compared to the pure PVA scaffold. The high porosity, swelling degree and hydrophilicity of PVA-AC composite scaffolds facilitated cell attachment and proliferation. This is due to porous AC present in the sample that supported the osteoblast differentiation and formed mineralized nodules without the addition of any extra agents. From the above studies, it can be concluded that PVA-AC composite scaffolds are promising biomaterials for bone tissue engineering applications.