Development of surface-treated poly(lactic acid)/zinc oxide biocomposites for 3D printing in bone tissue engineering

The increase in bone fractures has been driving the development of materials for bone repair with better mechanical and biological properties. This work reports the development of poly (lactic acid) (PLA)-zinc oxide (ZnO) biocomposites for 3D printing of scaffolds to be applied in bone tissue engineering. The ZnO surface was functionalized with maleic anhydride (ZnOMA) by applying radio frequency plasma treatment as an alternative to control the catalytic effects of ZnO on the degradation of the PLA during the molten state processing. PLA and ZnOMA powders were processed using a heated internal mixer and the resulted biocomposites were used to manufacture scaffolds by 3D printing. The scaffolds were characterized by their rheological, thermal, microstructural, mechanical, and biological properties. Compositions containing ZnOMA presented higher viscosities, evidencing the control of degradation by surface functionalization, and achieved an elastic modulus near 1 GPa, suitable for bone applications, unlike the untreated samples. In relation to cell functions, PLA-ZnOMA scaffolds exhibited cell viabilities at 160%, compared to 50% for untreated samples and stimulated mesenchymal stem cells toward osteoblast. Therefore, ZnO's negative thermal degradation effect on PLA was successfully overcome using plasma functionalization, enabling the 3D printing of bioactive scaffolds with great potential for application in tissue engineering. Surface-treated poly(lactic acid)/zinc oxide scaffolds forbone tissue engineering. image