Effect of Extreme Ultraviolet (EUV) Radiation and EUV Induced, N2 and O2 Based Plasmas on a PEEK Surface’s Physico-Chemical Properties and MG63 Cell Adhesion

Abstract

Polyetheretherketone (PEEK), due to its excellent mechanical and physico-chemical parameters, is an attractive substitute for hard tissues in orthopedic applications. However, PEEK is hydrophobic and lacks surface-active functional groups promoting cell adhesion. Therefore, the PEEK surface must be modified in order to improve its cytocompatibility. In this work, extreme ultraviolet (EUV) radiation and two low-temperature, EUV induced, oxygen and nitrogen plasmas were used for surface modification of polyetheretherketone. Polymer samples were irradiated with 100, 150, and 200 pulses at a 10 Hz repetition rate. The physical and chemical properties of EUV and plasma modified PEEK surfaces, such as changes of the surface topography, chemical composition, and wettability, were examined using atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and goniometry. The human osteoblast-like MG63 cells were used for the analysis of cell viability and cell adhesion on all modified PEEK surfaces. EUV radiation and two types of plasma treatment led to significant changes in surface topography of PEEK, increasing surface roughness and formation of conical structures. Additionally, significant changes in the chemical composition were found and were manifested with the appearance of new functional groups, incorporation of nitrogen atoms up to ~12.3 at.% (when modified in the presence of nitrogen), and doubling the oxygen content up to ~25.7 at.% (when modified in the presence of oxygen), compared to non-modified PEEK. All chemically and physically changed surfaces demonstrated cyto-compatible and non-cytotoxic properties, an enhancement of MG63 cell adhesion was also observed.

Strategies to improve bioactive and antibacterial properties of polyetheretherketone (PEEK) for use as orthopedic implants

“…The surface roughness of the modified PEEK is increased, and new functional groups are added at the same time. Moreover, the modified PEEK promoted the adhesion and proliferation of MG-63 ​cells [ 115 ].…”

“… [ 113 ] Calcium In vitro : increased cytocompatibility and differentiation. [ 114 ] Oxygen, nitrogen In vitro : promoted the adhesion and proliferation of MG-63 ​cells [ 115 ] ANAB treatment N/A In vitro : increased metabolic activity, proliferation, and differentiation; improved hydrophilicity of PEEK. [ 118 ] IBAD treatment YSZ, HA In vitro : increased cell growth and differentiation.…”

Strategies for Improved Wettability of Polyetheretherketone (PEEK) Polymers by Non-Equilibrium Plasma Treatment

“…Extreme UV radiation was used for the surface modification of PEEK samples by Czwartos [ 16 ]. The EUV was supplied in pulses and the intensity was large enough to cause the formation of plasma above the polymer surface.…”

Application of Porous Polyetheretherketone Scaffold/Vancomycin‐Loaded Thermosensitive Hydrogel Composites for Antibacterial Therapy in Bone Repair

“…As shown in Figure 3c-e, cells can survive on all surfaces of samples, but the number of pseudopod and relative surface area of cells on the surface of ps-PK-Gel and ps-PK-VGel was higher than it is on ps-PK, demonstrating that the cell adhesion capacity on surface ps-PK-Gel and surface ps-PK-VGel is stronger than that of ps-PK. [44,45]…”