Double protein functionalized poly-ε-caprolactone surfaces: in depth ToF-SIMS and XPS characterization

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Polymer Science

Background:

• Biomaterial surface modification is crucial for enhancing cell adhesion.
• Poly-ε-caprolactone (PCL) is a widely used biomaterial.
• Previous work established a method for PCL functionalization with 2-aminoethyl methacrylate (AEMA).

Purpose of the Study:

• To comprehensively characterize PCL surfaces functionalized with AEMA and subsequently coated with gelatin and fibronectin.
• To validate the effectiveness of Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and X-ray Photoelectron Spectroscopy (XPS) for surface analysis.
• To assess the impact of ethylene oxide sterilization on the modified surfaces.

Main Methods:

• Surface functionalization of PCL films via Ar-plasma treatment and UV-initiated AEMA grafting.
• Covalent immobilization of gelatin followed by fibronectin physisorption.
• In-depth surface analysis using XPS and ToF-SIMS.

Main Results:

• XPS and ToF-SIMS confirmed homogeneous AEMA grafting and successful protein coating.
• ToF-SIMS identified polymethacrylates and specific amino acid-related ions, distinguishing between gelatin and fibronectin.
• XPS analysis of C- and N-peaks confirmed protein presence.
• Ethylene oxide sterilization did not alter the surface chemical composition.

Conclusions:

• XPS and ToF-SIMS are complementary techniques for detailed characterization of biomaterial surface modifications.
• The developed surface modification strategy effectively immobilizes proteins, enhancing biomaterial properties.
• The modified surfaces exhibit stability towards common sterilization methods, indicating potential for biomedical applications.