Influence of spark plasma sintering and baghdadite powder on mechanical properties of hydroxyapatite

AbstractSince hydroxyapatite-based materials have similar composition and crystallinity as natural calcified tissues, can be used for bone/tissue engineering. In the present study a novel nanocomposite based on bioceramics such as Natural Hydroxyapatite (NHA) and Baghdadite (BAG), was sintered by spark plasma sintering (SPS) technique. The prepared composite was characterized using scanning electron microscopy (SEM), X-ray diffractometer (XRD) and Brunauer–Emmett–Teller (BET) techniques. The porosity of the samples was measured by Archimedes method. The cold crushing strength (CCS) test was applied to evaluate their mechanical properties. Our results demonstrated that NHA-30wt. %BAG nanocomposite specimens have the lower CCS in comparison with other examined composites. Consequently, NHA/BAG samples exhibited acceptable mechanical properties and could be suitable candidates for bone tissue engineering applications especially orthopaedic fields

Preparation, Characterization, Mechanical Properties and Electrical Conductivity Assessment of Novel Polycaprolactone/Multi-Wall Carbon Nanotubes Nanocomposites for Myocardial Tissue Engineering

Cardiac tissue engineering aims to create functional tissue constructs that can reestablish the structure and function of injured myocardium. In this study, nanocomposite scaffolds composed of polycaprolactone and multi-walled carbon nanotubes, containing different amounts of carbon nanotubes, were prepared via solvent casting and vacuum drying technique, for myocardial tissue engineering. Characterization techniques such as Fourier transform infrared spectroscopy and scanning electron microscopy were used. Furthermore, mechanical properties of the prepared polycaprolactone and nanocomposite scaffolds were determined. The results have revealed that the scaffolds contain sufficient porosity with highly interconnected pore morphology. Addition of carbon nanotubes to the polycaprolactone matrix has improved conductivity of the prepared scaffold. The desired distribution of carbon nanotubes with a few agglomerates was observed in the nanocomposite scaffolds by scanning electron microscopy. Polycaprolactone/multi-walled carbon nanotubes nanocomposite scaffold containing 1 wt% of carbon nanotubes has shown the best mechanical behavior and electrical conductivity. In conclusion, the electrically conductive and nanofibrous polycaprolactone/1 wt% multi-wall carbon nanotubes scaffold could be used as an appropriate construct for myocardium regeneration and it deserves further investigations

Biodegradable nanocomposite coatings accelerate bone healing: In vivo evaluation

Background: The aim of this study was to evaluate the interaction of bioactive and biodegradable poly (lactide-co-glycolide)/bioactive glass/hydroxyapatite (PBGHA) and poly (lactide-co-glycolide)/bioactive glass (PBG) nanocomposite coatings with bone. Materials and Methods: Sol-gel derived 58S bioactive glass nanoparticles, 50/50 wt% poly (lactic acid)/poly (glycolic acid) and hydroxyapatite nanoparticles were used to prepare the coatings. The nanocomposite coatings were characterized by scanning electron microscopy, X-ray diffraction and atomic force microscopy. Mechanical stability of the prepared nanocomposite coatings was studied during intramedullary implantation of coated Kirschner wires (K-wires) into rabbit tibia. Titanium mini-screws coated with nanocomposite coatings and without coating were implanted intramedullary in rabbit tibia. Bone tissue interaction with the prepared nanocomposite coatings was evaluated 30 and 60 days after surgery. The non-parametric paired Friedman and Kruskal-Wallis tests were used to compare the samples. For all tests, the level of significance was P < 0.05. Results: The results showed that nanocomposite coatings remained stable on the K-wires with a minimum of 96% of the original coating mass. Tissue around the coated implants showed no adverse reactions to the coatings. Woven and trabecular bone formation were observed around the coated samples with a minimum inflammatory reaction. PBG nanocomposite coating induced more rapid bone healing than PBGHA nanocomposite coating and titanium without coating (P < 0.05). Conclusion: It was concluded that PBG nanocomposite coating provides an ideal surface for bone formation and it could be used as a candidate for coating dental and orthopedic implants