In Vitro Studies and Evaluation of Antibacterial Properties of Biodegradable Bone Joints Based on PLA/PCL/HA

Background: Due to the history of using permanent implants and the ability of adaptations of polymers to physiological environments such as the body environment, the need to design a polymer implant with a new formulation for orthopedic applications was felt. Methods: Polymer joints in this study were made by solvent casting method. The mechanical properties of the samples were investigated by bending tests, before and after immersion in simulated body fluid (SBF). Morphology of nanocomposites, bioactivity of samples and initiation of degradation process were performed by field emission scanning electron microscope (FESEM). Toxicity test was performed to evaluate the toxicity of nanocomposites. The antibacterial properties of the samples were investigated by examining the zone of inhibition and measuring the photometric concentration. Biodegradability test was performed to prove the biodegradability of polymer joints. Results: It was found that the mechanical properties of nanostructures increased with the addition of nanoparticles. Also, the presence of oxide and graphene nanoparticles affected the antibacterial properties of the composite nanostructure. Immersion in SBF solution showed that the nanostructures were biodegradable and bioactive. The results of this study indicate that the optimal nanocomposite PLA-PCL-HA-1% ZNO-1% GR has a Young’s modulus close to spongy bone and reduces the stress shielding phenomenon. The flexural Yang modulus of the PLA-PCL-HA nanocomposite was 2139.037 ± 381.312 MPa. The presence of zinc oxide and graphene nanoparticles increased the Young’s modulus to 4363.636 ± 127.498 MPa. The optimal sample has the necessary lethality against two strains of gram-positive and gram-negative bacteria and due to its bioactivity is a suitable option for use in spongy bone tissue. In this study, the viability of fibroblast cells in the vicinity of the polymer matrix versus the optimal matrix increased from 22.14 ± 0.623 to 82.96 ± 1.101% after 72 hours. Conclusions: Improving cell viability indicates a reduction in the optimal matrix toxicity compared to the polymer matrix.