Novel process of non-sintered HAp/SF biocomposite for bone regeneration

Reference	Presenter	Authors (Institution)	Abstract
02-023	Sergio Akinobu Yoshioka	Vieira, D.(Programa de Pós-Graduação Interunidades em Bioengenharia (EESC/FMRP/IQSC) - USP São Carlos); Gutiérrez, S.(Universidade de São Paulo); Castro Máximo Bicalho, S.M.(JHS Biomateriais); Yoshioka, S.A.(Universidade de São Paulo);	A novel process of bone regeneration material was made by non-sintered hydroxyapatite and silk fibroin biocomposite (75%HAp/25%SF) based on a co-precipitation route. Hydroxyapatite (HAp) is a biomaterial widely used as bone graft substitute due to its biocompatibility and osteoconductive properties; however the low strength limits its potential applications. Silk fibroin (SF) has great mechanical properties, high biocompatibility and controllable degradation rates, and high thermal properties (temperature degradation >150oC). HAp/SF based composites increase the mechanical properties, so they have been explored for bone graft substitution. The degummed silk fibroin was dissolved in a ternary solution, CaCl2 aqueous/ethanol, and then, the hydroxyapatite was coprecipited with addition of phosphate solution at pH9.0. The composite was pressed by cold isostatic pressing to enhance the mechanical strength, compaction pressures of 50 and 100MPa and drying oven at 60oC were used. The structure and properties of the biocomposite were investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Ca/P ratio, water uptake, porosity and compressive strength. The results showed that the new biocomposite presents uniform distribution of HA and SF, with high porosity and a good compressive strength, like the trabecular bone. The composite relation Ca/P is mimetic to bone. The structure analyses confirm that the mix of HAp/SF don’t change the structure of silk fibroin (ß-sheets). The 75%HAp/25%SF non-sintered biocomposite proved to be a promising biomaterial for bone tissue engineering.
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