Surface Modification of Sulfonated Carbon Fiber-Reinforced Polyetheretherketone Composite by Polydopamine-Assisted nHA/Zn/CMCS and Its Evaluation of Osteogenic Properties

Abstract

Objective Carbon fiber-reinforced polyetheretherketone (CF/PEEK) possesses the elastic modulus similar to that of natural bone, yet its inherent surface hydrophobicity and bio-inertness restrict its application in oral implantation. To overcome this limitation, this study proposes the layer-by-layer surface functionalization strategy to construct the multifunctional CF/PEEK-based composite that integrates long-term antibacterial activity with synergistic osteogenic functions. Methods After sulfonation of CF/PEEK with 98% H₂SO₄, the polydopamine-assisted nanohydroxyapatite (PDA-nHA) intermediate layer and the zinc-loaded carboxymethyl chitosan (Zn/CMCS) coating were sequentially constructed, yielding the SCP-PHA-Zn/CMCS composite. A series of Characterizations including surface morphology, in vitro mineralization, antibacterial evaluation, cytocompatibility, osteogenic property, and osteogenesis-related gene mRNA expression levels were performed to assess in vitro biocompatibility and osteogenic performance. Results SEM showed SCP-PHA-Zn/CMCS possessed the 3D porous network, with uniformly deposited PDA-nHA presenting a fibrous network after Zn-CMCS wrapping. After SBF immersion, spherical apatite particles deposited on all samples. Water contact angles of SCP-PHA and SCP-PHA-Zn/CMCS were significantly lower than SCF/PEEK. SCP-PHA-Zn/CMCS significantly inhibited Staphylococcus aureus and Escherichia coli. All groups showed good biocompatibility and long-term biosafety. rBMSCs on SCP-PHA-Zn/CMCS showed the highest adhesion density, proliferation, ALP activity, matrix mineralization, and osteogenesis-related gene mRNA expression levels, significantly outperforming the other groups and demonstrating the best in vitro osteogenic capacity. Conclusion To address the surface hydrophobicity and bioinertia of CF/PEEK, this study successfully constructed the multifunctional SCP-PHA-Zn/CMCS composite using sulfonation pretreatment and the layer-by-layer functionalization assembly strategy. The obtained material exhibited favorable physicochemical properties, excellent biocompatibility and antibacterial performance, and significantly promoted the adhesion and proliferation of rBMSCs, enhanced ALP activity, matrix mineralization, and osteogenesis-related gene mRNA expression levels, demonstrating outstanding in vitro osteogenic capacity. These findings provide experimental evidence and a novel design strategy for the clinical translation of CF/PEEK in oral implantation and bone defect repair.