Dual surface modification of medical-grade PEEK: Nanosecond laser pre-treatment and hydrothermal hydroxyapatite coating

Polyetheretherketone (PEEK) is a high-performance biomedical material, yet its clinical utility is constrained by inherent bioinertness. In this study, we propose a dual modification strategy combining nanosecond laser treatment with hydrothermal synthesis of hydroxyapatite (HA). Nanosecond laser treatment was used to increase the surface roughness and hydrophilicity of PEEK, while introducing amorphous carbon and hydroxyl functional groups to enhance its calcium-phosphorus deposition capability. Subsequently, a dense and continuous HA coating was deposited on the laser-treated PEEK surface via hydrothermal synthesis. The results demonstrated that the laser-treated PEEK surface substantially enhanced the bonding strength with the HA coating, thereby improving the bioactivity of PEEK. Further characterization analyses, including X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), revealed that changes in the chemical composition and crystal structure of the PEEK surface during the modification process were key factors in improving the quality of the HA coating. Our proposed method is cost-effective, non-cytotoxic, and scalable, offering a high-performance solution for PEEK applications in the medical field, such as bone tissue repair and implant enhancement. It also provides new insights into the development of advanced medical polymer materials.