In this research, for the first time, the bioactivity characteristic of citric acid- modified sawdust (CA-SD) in the ability to form hydroxyapatite in simulated body solution (SBF) was investigated. Using various analyses such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and X-ray energy dispersive (EDX), the formation of hydroxyapatite on its surface was confirmed. Based on the green method, pure chitosan (CS) and bionanocomposites based on CS containing CA-SD, silver (Ag) nanoparticles and different percentages of TiO2 nanoparticles (0.5, 1, 1.5 and 2 wt%) was prepared in the form of spherical beads based on the green method. During the sample preparation process, glutaraldehyde (Glu) was used as a crosslinker. The use of crosslinkers creates strong scaffolds for the deposition of hydroxyapatite layers on them for use in bone tissue engineering. In addition, their solubility in water and SBF solution and the release of nanoparticles ions in SBF solution have decreased. CS composite and CS/CA-SD/Ag/TiO2 nanocomposites were identified by performing FT-IR, XRD, FE-SEM, and EDX techniques. Then, their bioactivity and antibacterial properties were eva‎luated. By considering different analyses, it was determined that hydroxyapatite layers were formed on the surface of all samples. But CS/CA-SD/Ag/TiO2 nanocomposite contaning 2% TiO2 nanoparticles had the best biological activity performance. Pure CS composite and CS/CA-SD/Ag/TiO2 nanocomposite contaning 2% wt% TiO2 nanoparticles showed good antibacterial activity, so this nanocomposite killed a large number of bacteria after 1h. These results along with the confirmation of non-toxicity showed that the prepared scaffolds can be used in the field of bone tissue engineering.

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محمد ديناري , عليرضا نجفي چرمهيني