Synthesis and characterization of collagen scaffolds reinforced by eggshell derived hydroxyapatite for tissue engineering

In this work, we synthesized porous nanohydroxyapatite/collagen composite scaffold (nHA-COL), which resemble extracellular matrices in bone and cartilage tissues. Nano hydroxyapatite (nHA) was successfully nucleated in to the collagen matrix using hen eggshell as calcium biogenic source. Porosity was evaluated by apparent and theoretical density measurement. Porosity of all scaffolds was in the range of 95–98%. XRD and TEM analyses show the purity and size of nucleated HA around 10 nm and selected area electron diffraction (SAED) analysis reveals the polycrystalline nature of nucleated HA. SEM analysis reveals (i) all the scaffolds have interconnected pores with an average pore diameter of 130 micron and (ii) aggregates of hydroxyapatite were strongly embedded in the collagen matrix for both composite scaffolds compared with pure collagen scaffold. EDS analysis shows the Ca/P stoichiometric ratio around 1.67 and FTIR reveals the chemical interaction between the collagen molecule and HA particles. The testing of mechanical properties evidenced that incorporation of HA resulted in up to a two-fold increase in compressive modulus with high reinforcement level (∼ 7 kPa for 50HA–50COL) compared to pure collagen scaffold