Synthesis of Mesoporous Hydroxyapatite with Controlled Pore Size Using the Chitosan as an Organic Modifier: Investigating the Effect of the Weight Ratio and pH Value of Chitosan on the Structural and Morphological Properties

摘要

In the present research, the mesoporous hydroxyapatite nanoparticles were synthesized by the chemical precipitation method in the absence and presence of different weight ratios (0, 0.1, and 0.3 g) of chitosan as an organic modifier. The effects of different weight ratios and pH values (8, 9, and 10) of chitosan on the structural characteristics of the mesoporous hydroxyapatite nanoparticles were also investigated. Then, all the prepared samples were calcined at 650 degrees C for 3 h and their structure, morphology, surface area, and pore size distribution were characterized by X-ray Diffraction (XRD) technique, Field Emission Scanning Electron and Transmission Electron Microscopy (FE-SEM & TEM), Fourier Transform Infrared spectroscopy (FT-IR), Energy Dispersive X-ray spectrometer (EDX), and finally Brunauer-Emmett-Teller (BET) technique. The XRD analysis showed that the crystalline size of the synthesized HA decreased from 38 to 24 nm at pH 8, 40 to 30 nm at pH 9 as well as from 48 to 32 nm at pH 10. The same trend of decrease in the crystalline size was observed when the chitosan concentration increased from 0.0 to 0.3 g. The results revealed that the crystalline size, pore size, and surface area of the synthesized HA can be controlled by adjusting the chitosan weight ratio in the initially prepared samples. Mesopores in HA were observed for the samples synthesized at different pH values, by removing the organic template. Furthermore, the pore size of the prepared chitosanHA samples was found to be 13-38 nm, which seems to be suitable for cell attachment and slow-release drug delivery, especially in treatment of osteoporosis.