Apatite-forming PEEK with TiO2 surface layer coating.

Orthopedic implants often require stable integration with bone tissue. Polyetheretherketone (PEEK) is commonly used due to its mechanical properties but lacks the ability to bond directly to bone. This limitation necessitates the use of bone grafts for fixation. While titanium dioxide (TiO2) coatings have been explored for enhancing osseointegration, challenges remain in ensuring strong adhesion of TiO2 to PEEK surfaces. Existing methods often involve complex pretreatments or fail to achieve durable bonding. This gap motivated the investigation of surface treatments that could improve TiO2 adhesion on PEEK without extensive preprocessing. No prior work had resolved the issue of weak TiO2 adhesion on untreated PEEK surfaces. The need for a reliable, simple method to coat PEEK with TiO2 remains unmet. This study aimed to address that limitation by exploring the effects of UV and plasma pretreatments on TiO2 adhesion. The potential for these treatments to enhance osseointegration was also examined.

This study aimed to develop a TiO2 coating on PEEK that promotes bone bonding. The goal was to evaluate whether surface pretreatment could improve TiO2 adhesion to PEEK. The specific problem addressed was the weak adhesion of TiO2 coatings on untreated PEEK surfaces. The motivation stemmed from the need for a reliable, straightforward method to enhance PEEK's integration with bone. The study sought to determine whether UV or O2 plasma pretreatment could strengthen TiO2 adhesion. The researchers also aimed to assess whether the coated PEEK could support apatite formation, a key indicator of bone bonding. The study focused on the sol-gel process as a coating method due to its simplicity and compatibility with PEEK. The ultimate aim was to create a PEEK implant with improved osseointegration potential.

The study used sol-gel processing to deposit TiO2 on PEEK substrates. The TiO2 sol was prepared from titanium isopropoxide, water, ethanol, and nitric acid. Some PEEK samples were pretreated with UV or O2 plasma before coating. Untreated PEEK samples were also coated for comparison. After deposition, the TiO2 gel layers were evaluated for adhesion. Adhesion was tested after subsequent treatments such as heating. Surface characterization was performed using spectroscopic methods to identify chemical interactions. Apatite formation was assessed by immersing samples in simulated body fluid (SBF) and in acidic conditions. The effect of acid treatment on surface charge was also measured to explain apatite formation.

TiO2 gel layers on untreated PEEK surfaces were easily peeled off after processing. In contrast, UV or O2 plasma pretreatment significantly improved TiO2 adhesion to PEEK. Spectroscopic analysis showed that surface functional groups on PEEK interacted with TiO2 bonds. Apatite did not form on TiO2-coated PEEK in SBF for up to three days. However, after soaking in 0.1 M HCl at 80 °C for 24 h, apatite formed on the TiO2 layer. This apatite formation was linked to the positive surface charge induced by acid treatment. The study found that pretreated PEEK with TiO2 coating could support rapid apatite formation. These findings suggest that the proposed process could enhance PEEK's bone-bonding properties.

The study demonstrated that UV or O2 plasma pretreatment enhances TiO2 adhesion to PEEK surfaces. The improved adhesion was attributed to chemical interactions between PEEK functional groups and TiO2. Apatite formation on TiO2-coated PEEK was observed after acid treatment but not in SBF alone. This suggests that the TiO2 layer can support apatite formation under specific conditions. The researchers propose that the positively charged TiO2 layer facilitates rapid apatite formation in SBF. The findings suggest that the proposed coating process could improve PEEK's integration with bone. The study supports the potential of this method for orthopedic applications. Further research may explore how these findings translate to in vivo settings.