Chitosan-hydroxyapatite macroporous matrix for bone tissue engineering

In recent years, bone tissue engineering which involves cells, three-dimensional (3-D) matrix and/or recombinant signalling molecules has been extensively studied to find an ideal bone implant. The scaffold for bone tissue engineering should be porous to allow mass transfer at high rate along with mechanical property in par with bone structure to ensure integrity of neo-tissue. In this work, we have combined well-known hydroxyapatite (Ca-10(PO4)(6)(OH)(2); HA) and chitosan that provides ideal surface chemistry for its osteoblast attachment and enhances mineralization and is known for its osteoconductive and osteoinductive properties. We have synthesized chitosan hydroxyapatite (CH HA) macroporous scaffold, in simple two-step process, using freeze-drying technique. Scanning electron microscope analysis showed macroporous architecture with interconnected pores. EMAX testing for elemental analysis clearly indicated presence of calcium, phosphorus and sodium along with oxygen and nitrogen in the scaffold. The Fourier's transmission infrared spectroscopy (FTIR) examination showed chemical bonding between both the polymers. To further evaluate 3-D profiling of CH HA scaffold, rheological testing was performed which showed no significant change in G', G '' and phase angle proving mechanical stability of the material which was able to bear stress without leading to deformation. Human osteoblast seeded on CH HA matrices showed enhanced cellular proliferation and viability for longer period of time. Increased mineral deposition was examined using alkaline phosphatase assay which confirmed that CH HA scaffold provided conducive environment for osteoblast proliferation and mineral deposition. The mechanical properties and microarchitecture of the scaffold were found to be ideal for bone tissue engineering.This work was fully supported by the 2009 Yeungnam University research grant