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Osteoblastic and chemical responses to Poly (ether ether ketone) (PEEK) material have been improved using a variety of low-temperature plasmas (LTPs). Surface chemical properties are modified, and can be used, using low-temperature plasma (LTP) treatments which change surface functional groups. These functional groups increase biomineralization, in simulated body fluid conditions, and cellular viability. PEEK scaffolds were treated, with a variety of LTPs, incubated in simulated body fluids, and then analyzed using multiple techniques. First, scanning electron microscopy (SEM) showed morphological changes in the biomineralization for all samples. Calcein staining, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) confirmed that all low-temperature plasma-treated groups showed higher levels of biomineralization than the control group. MTT cell viability assays showed LTP-treated groups had increased cell viability in comparison to non-LTP-treated controls. PEEK treated with triethyl phosphate plasma (TEP) showed higher levels of cellular viability at 82.91% ± 5.00 (n = 6) and mineralization. These were significantly different to both the methyl methacrylate (MMA) 77.38% ± 1.27, ethylene diamine (EDA) 64.75% ± 6.43 plasma-treated PEEK groups, and the control, non-plasma-treated group 58.80 ± 2.84. FTIR showed higher levels of carbonate and phosphate formation on the TEP-treated PEEK than the other samples; however, calcein staining fluorescence of MMA and TEP-treated PEEK had the highest levels of biomineralization measured by pixel intensity quantification of 101.17 ± 4.63 and 96.35 ± 3.58, respectively, while EDA and control PEEK samples were 89.53 ± 1.74 and 90.49 ± 2.33, respectively. Comparing different LTPs, we showed that modified surface chemistry has quantitatively measurable effects that are favorable to the cellular, biomineralization, and chemical properties of PEEK.
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This content will become publicly available on September 23, 2026
Porous Additively Manufactured PEKK Improves In Vitro Osteoblastic Performance Compared to PEEK
ABSTRACT Polyetheretherketone (PEEK) is a member of the polyaryletherketone (PAEK) family of semi‐crystalline thermoplastics that is increasingly considered as an alternative to metals for use in permanent implants. Another member of the PAEK family, polyetherketoneketone (PEKK), has many similar properties to PEEK, but can vary in its crystallization kinetics due to its varying terephthalic and isophthalic acid (T/I) ratios during manufacturing. We hypothesized that PEKK's differences in chemical structure may produce a better surface for cell adhesion, increasing in vitro osteoblastic performance when compared to PEEK. Solid and porous samples were printed under comparable conditions and cultured with MC3T3‐E1 mouse pre‐osteoblasts for up to 28 days. A laser confocal microscope was used to evaluate surface roughness of samples as one possible explanation for differences in in vitro performance. Micro‐CT was used to visualize the accuracy in printing of porous samples when compared to a digital model. PEKK samples were found to have significantly increased cell attachment, normalized alkaline phosphatase activity, and osteoblastic mineralization at multiple time points (p < 0.05). PEKK samples were also found to be significantly smoother than PEEK samples on the micron scale. Based on micro‐CT images, PEKK samples were found to more closely resemble the desired triply periodic minimal surface geometry than PEEK samples. This study suggests that PEKK should be considered in future studies investigating the biological performance of PEEK due to PEKK's encouraging in vitro biocompatibility.
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- Award ID(s):
- 2216175
- PAR ID:
- 10642004
- Publisher / Repository:
- Journal of Orthopaedic Research
- Date Published:
- Journal Name:
- Journal of Orthopaedic Research
- ISSN:
- 0736-0266
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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