Biomimetic Scaffolds from Hydroxyethyl Cellulose/Calcium Phosphate for Bone Tissue Engineering Applications

Hydroxyapatite (HA) crystals inside the pores of hydroxyethyl cellulose (HEC) sponges have been developed using simulated body fluid (SBF) in a green chemistry approach and has been used as a scaffold material. Porous HEC sponges were prepared by freeze-drying method. HEC is a water soluble polymer which is non-toxic and biocompatible. The crystallization of hydroxyapatite (HA) was done by immersing HEC sponges (1 wt%, 3 wt% and 5 wt%) into various concentration of simulated body fluid (SBF) for different time periods. For the analysis of these materials, various bulk and particle level characterization techniques have been employed, which includes Field transmission scanning electron microscopy (FESEM), Scanning Electron Microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD) and mechanical testing. Energy dispersive X-ray (EDX) analysis was used to confirm the deposition of apatite on the surface of HEC sponges. It was found that porosity, pore size and pore inter connectivity depends upon the concentration of the HEC. The size of the HA crystals increased with the concentration of the HEC. The sponges had pores with diameter~2-200μm and pores were interconnected. In-vitro testing with human dental pulps stem cell (DPSC) was also conducted to assess its biocompatibility. In-vitro bioactivity and biodegradability studies showed that the HEC/HA scaffolds were bioactive as well as bioresorbable. Combining hydroxyapatite into hydroxyethyl cellulose may generate a composite with favorable mechanical and chemical properties that are appropriate for various medical applications