Preparation and Evaluation of Digital 3D-Printed PLA/nHA/CNTs-CG Composite Bone Tissue-Engineering Scaffold for Enhanced Osteogenic and Antibacterial Properties

In bone tissue reconstruction, infection is a critical limiting factor affecting treatment efficacy. So it is necessary to introduce antibacterial agents onto scaffold surfaces for functional modification while balancing osteoblast activity. Carbon nanotubes (CNTs), with their exceptional osteogenic properties and drug-loading capacity, emerge as ideal materials. Digital 3D printing technology was employed to composite CNTs loaded with the antibacterial agent chlorhexidine gluconate (CG) with polylactic acid-nano hydroxyapatite (PLA/nHA), and a novel composite scaffold with a controllable porous structure (PLA/nHA/CNTs-CG) was successfully constructed. TEM observations revealed the hollow structure of CNTs, while XPS, XRD, N2 adsorption–desorption tests, and TGA confirmed successful CG loading. SEM analysis demonstrated the porous network-like structure of PLA/nHA/CNTs-CG scaffolds, exhibiting compressive strength of (8.44 ± 0.24) MPa. Initial biosafety validation through CCK-8 assay, live/dead cell staining, and hemocompatibility tests confirmed good biocompatibility. Cell adhesion experiments demonstrated enhanced cellular attachment on PLA/nHA/CNTs-CG scaffolds. Osteogenic performance tests revealed that CNTs incorporation improved MC3T3-E1 cell osteogenic differentiation, with CG presence not compromising scaffold osteogenic activity. Antibacterial experiments demonstrated potent antibacterial effects against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The PLA/nHA/CNTs-CG composite scaffold demonstrates dual functionality in infectious bone defect repair by simultaneously promoting bone regeneration and exerting antibacterial effects, providing novel insights for designing bone repair materials for infected defects.