In-vitro Evaluation of Layered Double Hydroxide/HA Composite Scaffoldsfor Bone Tissue Engineering Applications

Pure layered double hydroxide (LDH), and Layered double hydroxides/hydroxyapatitenanocomposite (LDH/HA ratio=۷۵/۲۵) powders were synthesized via a co-precipitationmethod. Aluminumnitrate, calciumnitrate and calcium hydrogen phosphate were used asstarting materials, the reactions were carried out under controlled pH at the alkaline range, andafter ۲۲h aging were washed and dried. XRD, FTIR, and SEM techniques were used tocharacterize the chemical composition and microstructure of resulted powders. The resultsverified the presence of nanocrystals of HA and Ca-LDH. Gelatin was added to the powdersusing solvent casting method, and then the produced composites were freeze-dried. Theresulting materials were exposed to glutaraldehyde ۱% solution for ۲۴h to become cross-linked,then the scaffolds were thoroughly washed with graded alcohols and distilled water three times.The porosity of the scaffold was measured by Archimedes' method. To evaluate thecytotoxicity of samples, the powders and scaffolds were immersed in a RPMI cell culturemedium for ۳, ۷ and ۱۴ days and the resulted extracts encompassed in exposure of the humanosteosarcoma cell line (G-۲۹۲) for ۲۴h. The MTT-assay showed that not only the samples haveno toxicity, but also the show a better cellular response in comparison with the CTRL sample;and statistically viability increased. The results of in-vitro evaluation confirmedbiocompatibility and surface bioactivity of LDH. After ۴۸h of exposing of the cells intoscaffolds surfaces, the SEM images showed well-behaved adhesion and spreading of cells andthe scaffolds degradation. Based on this research's results, these novel composites havepromising potential for bone tissue engineering applications.

Keywords:

Layered double hydroxides , Hydroxyapatite , Scaffold , Nanocomposite , Bonetissue engineering , Biological evaluation