Zinc oxide whisker-loaded antibacterial 3D-printed polylactic acid based composite bone scaffolds with enhanced biological and mechanical performance

A bone scaffold for addressing infectious bone defects should possess not only good mechanical and biological performance but also effective antibacterial function. In this study, we developed a bone scaffold based on polylactic acid (PLA) loaded with zinc oxide (ZnO) whiskers using FDM 3D printing and systematically investigated the impact of varying loading content of ZnO on the antibacterial performance, biological performance, mechanical properties, and physicochemical properties of the composite scaffold. Antibacterial experiments using optical density and spread plate method revealed that the ZnO-loaded scaffolds exhibited high antibacterial activity both against E. coli and S. aureus, positively correlating with the content. SEM characterization revealed obvious deformation and rupture in the morphology of bacteria under the action of ZnO, which was mainly attributed to the production of ROS. Cell culture indicated the cell proliferation and osteogenic differentiation was enhanced with appropriate content of ZnO. Mechanical test results demonstrated that appropriate content of ZnO enhanced the compression strength of the composite scaffold. This study demonstrates that ZnO whiskers can be utilized as a versatile inorganic filler for simultaneously enhancing antibacterial, mechanical, and biological performance of 3D-printed polymer bone scaffolds designed for addressing infectious bone defects.