Fabrication and characterization of chitosan / hydroxyapetite nano composites for tissue engineering applications using locally derived chitosan

Abstract

In this research work (70/30) nanocomposites of Chitosan (CS) biopolymer and Hydroxyapatite (HA) ceramic powder were synthesized by insitu co-precipitation technique at different reflux temperatures, combined with double step stirring. Initially medical grade chitosan was extracted in the laboratory using locally available shrimp species known as Penaeus Monodon. Extraction of chitosan involved four main stages as preconditioning, demineralization, deprotenisation and deacetylation. Further purifications and modifications were done on extracted chitosan to obtain medical grade chitosan. To synthesize the nanocomposite, analytical grade acetic acid, H3PO4 and Ca(OH)2 used as starting materials. At first, chitosan was dissolved in acetic acid and mixed with required amount of H3PO4 acid. Then the chitosan / H3PO4 solution was added drop wise into the highly alkaline Ca(OH)2 suspension. During the addition chitosan precipitated with hydroxyapatite by forming the chitosan/ hydroxyapatite composite. The precipitate was filtered and washed with distilled water. Then the precipitate was subsequently compressed into a cylindrical form under a uniaxial pressure. Synthesized composite was characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and differential thermal analysis (DTA). The XRD spectrum demonstrated relevance peaks of chitosan and HA in composite. FTIR spectrum of composite showed the characteristics bond energies of chitosan sample and hydroxyapatite sample. SEM images demonstrated a uniform hydroxyapatite particle distribution in the Chitosan matrix. Each characterization techniques confirm the existence of chitosan and HA in the composite. The size of the HA crystals embedded in composite was calculated using Scherrer formula and it was found to be ~80nm to 100 nm. The basic materials properties of the composite are compatible with the properties of biomaterials that are intended to be used in tissue engineering applications. Therefore, it can be concluded that (70/30) nanocomposites of Chitosan biopolymer and Hydroxyapatite ceramic powder of nano size particles have been successfully synthesized with required material properties