Preparation of chitosan‐nanohydroxyapatite composite scaffolds by a supercritical CO₂ assisted process

Abstract In this study, chitosan‐nanohydroxyapatite composite scaffolds were prepared by a supercritical fluid assisted process. For this purpose, different amounts of nanohydroxyapatite particles, that is, 0.25, 0.50, and 1.00 wt% were added to chitosan (deacetylation degree: DD 75–85%) solution (2%, w/v, in acetic acid). The gels were then frozen at −20°C, treated in acetone and dried in a supercritical fluid extractor under a constant CO₂ flow of 15 g/min at 35°C and 200 bar for 5 h to obtain porous scaffolds. Scanning electron microscope views showed that the drying of gels under supercritical CO₂ lead to the formation of microporous scaffolds with a pore size distribution of 30–150 μm. Addition of nanohydroxyapatite particles did not significantly affect the pore size distribution. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy and X‐Ray diffraction analyses supported the successful incorporation of nanohydroxyapatite particles in the scaffold. An increase in water uptake and mechanical strength were observed in composite scaffolds. The results obtained from this study indicated that chitosan‐nanohydroxyapatite scaffolds prepared by using supercritical CO₂ shall be considered as a potential candidate for bone tissue engineering applications. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers