Plasma-Induced Amine-Modified PEEK Promotes Osteointegration via Multiple Osteogenic Pathways and Macrophage...

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Surface Chemistry

Background:

• Polyetheretherketone (PEEK) is widely used in orthopedic devices due to its favorable mechanical and chemical properties.
• However, PEEK's biological inertness limits initial fixation and bone integration, potentially compromising implant success.
• Existing surface modification methods for PEEK have drawbacks, including inconsistent roughness and wear debris generation.

Purpose of the Study:

• To investigate the osteogenic effects of PEEK modified by plasma-enhanced chemical vapor deposition (PECD) with a carbonaceous thin film containing amine groups.
• To elucidate the underlying molecular mechanisms responsible for enhanced bone formation.
• To evaluate the in vivo performance of plasma-treated PEEK in a rat femur model.

Main Methods:

• PEEK surface modification using plasma-enhanced chemical vapor deposition (PECD) with CH4/N2 gas.
• In vitro assessment of hydrophilicity, cell adhesion, and osteoblastic differentiation.
• RNA sequencing analysis to identify signaling pathways involved in osteogenesis.
• In vivo implantation into rat femurs to evaluate bone-bone bonding and tissue response.

Main Results:

• Plasma-treated PEEK exhibited enhanced hydrophilicity and cell adhesion without altering surface roughness.
• In vitro studies showed promoted osteoblastic differentiation on plasma-treated PEEK.
• RNA sequencing revealed activation of FAK and BMP4/Smad signaling pathways.
• In vivo, plasma-treated PEEK demonstrated bone formation without fibrous tissue intervention, unlike untreated PEEK, with superior bone quality at 6 weeks.

Conclusions:

• Plasma treatment using PECD effectively enhances the osteogenic potential of PEEK by improving surface properties and activating key signaling pathways.
• This modification overcomes the biological inertness of PEEK, leading to improved bone bonding and implant integration.
• Plasma-treated PEEK shows significant promise as a next-generation biomaterial for orthopedic applications.