In vitro and in vivo assessment of 3D-printed PCL/PLA/ZnO nanocomposite scaffolds for osteoarthritis treatment

3D scaffolds that mimic the extracellular matrix can be a promising alternative to bone grafting in the treatment of bone injuries. This study aimed to develop 3D-printed PCL/PLA/ZnO scaffolds and evaluate their physical and biological properties for potential application in osteoarthritis-related bone and cartilage repair. Scaffolds of PCL containing 0, 1, 2, and 3 wt % ZnO and PLA were printed layer by layer. Polycaprolactone is widely recognized as a biocompatible and bioactive material and to enhance its biodegradability and hydrophilicity, polylactic acid was incorporated. Additionally, ZnO can improve mechanical and biological characteristics. Results showed that the PCL/PLA samples exhibit more hydrophilic surfaces compared to pure PCL samples, which can enhance cell adhesion, growth, and proliferation. In vitro assessments showed that these samples are biodegradable and bioactive, could support cell attachment, proliferation and differentiation to bone cells and intensified calcium mineralization. The PCL/PLA/2 %ZnO had the best result and was chosen for in vivo assessment. Considering the involvement of articular cartilage in osteoarthritis, this scaffold was investigated in a rabbit model of osteoarthritis for cartilage tissue repair. Histological evaluations indicated improved cellular organization in the treated sites. Additionally, the scaffolds contributed to a reduction in inflammation. These findings suggest that the scaffold serves as a dual-function support structure, making it a promising candidate for the treatment of joint-related injuries such as osteoarthritis. Ultimately, this research establishes a foundation for further investigation into the multifunctional application of such scaffolds in regenerative medicine, with the potential to improve joint function and patient outcomes.