In this study, a novel method for surface modification of bioceramic scaffolds intended for bone substitute applications was investigated. Hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂) obtained from the pyrolysis of bovine bone at 1200 °C was used as the base material. An inorganic matrix with a porous and hydrophilic structure was formed, closely resembling human cancellous bone. Surface modification of the hydroxyapatite scaffolds was performed using carboxymethyl chitosan and zinc oxide. The prepared scaffolds were characterized using X‑ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Comparative analysis of scaffold porosity indicated that the hydroxyapatite–carboxymethyl chitosan scaffold exhibited higher porosity compared with pure hydroxyapatite and hydroxyapatite scaffolds coated with zinc‑oxide‑modified carboxymethyl chitosan. Mechanical testing (stress–strain analysis) showed that the hydroxyapatite scaffold coated with carboxymethyl chitosan exhibited the highest mechanical strength. SEM images revealed that the hydroxyapatite scaffold coated with zinc‑oxide‑modified carboxymethyl chitosan possessed an interconnected porous structure. Two bacterial strains, the Gram‑positive Staphylococcus aureus (ATCC 25922) and the Gram‑negative Escherichia coli (ATCC 25923), were used to evaluate the antibacterial activity of the fabricated scaffold. The results demonstrated that the hydroxyapatite scaffold coated with zinc‑oxide‑modified carboxymethyl chitosan produced inhibition zones of 20 mm and 23 mm against E. coli and S. aureus , respectively.
Dowlatabadi et al. (Sun,) studied this question.