Preparation and characterization of chitosan/hydroxyapatite scaffolds containing mesoporous SiO2-HA for drug delivery applications

In this study, chitosan/hydroxyapatite/mesoporous SiO2-HA scaffolds were prepared by the freeze-drying method, and their properties were investigated for drug delivery applications. Synthesized hydroxyapatite (HA) powder and mesoporous SiO2-HA particles were studied by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). Different amounts of chitosan (CS) (1-3 wt%) and HA (1-4 wt%) were used to prepare the scaffolds, and their morphologies was observed by FESEM. The images showed that the scaffolds had large-sized pores, and adding 2 wt% mesoporous SiO2-HA particles to scaffolds improved their porous nature. Although the pore size of the scaffolds became smaller by adding hydroxyapatite, the inclusion of mesoporous SiO2-HA made the pore size smaller. XRD results affirmed a strong interaction between chitosan and hydroxyapatite in scaffolds. The compressive strength reached 18.76 MPa by adding hydroxyapatite to CS, and 23.9 MPa by adding mesoporous particles to the scaffolds. The swelling ratio of CS/HA scaffolds equaled to 1.02, and it decreased to 0.17 by adding mesoporous SiO2-HA which indicates the best stability of mesoporous-containing scaffolds inside fluids. It was also shown that the amount of tramadol released from the CS/HA/mesoporous SiO2-HA scaffold reached 98% after 240 h. All tests confirmed that the introduction of adding mesoporous SiO2-HA to CS/HA scaffolds boosted their both mechanical and biological performances.