Effect of graphite, graphene oxide, and multi-walled carbon nanotubes on the physicochemical characteristics and biocompatibility of chitosan/hyaluronic acid/hydroxyapatite scaffolds for tissue engineering applications

Bone tissue engineering (BTE) is a promising alternative approach to the repair of damaged bone tissue. This study aims to fabricate and characterize scaffolds composed of chitosan (CS), hyaluronic acid (HA), hydroxyapatite (HAp), and a combination of graphite (Gr), graphene oxide (GO), and multi-walled carbon nanotubes (MWCNT) for BTE applications. The Gr and MWCNT were functionalized by acid oxidation, while the GO was synthesized using the improved Hummer method. The scaffolds were prepared by lyophilization, and the physical, chemical, and biological properties were evaluated. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, mechanical testing, water contact angle, degradation, and biocompatibility assays were used to characterize the scaffolds. The degradation rate was determined using the liquid displacement method. Pores of different sizes were present on the surface of and throughout the scaffold. According to the FTIR results, the scaffolds contained functional groups that promote cell differentiation and proliferation. These scaffolds have compressive strength, Young's modulus, and toughness similar to cancellous bone, with reasonable porosity and controllable degradation rates. Biocompatibility testing confirmed that the scaffolds support cell proliferation and differentiation.