Conformational changes of fibrinogen after adsorption

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Spectroscopy

Background:

• Protein adsorption on biomaterials is crucial for biocompatibility.
• Understanding fibrinogen's conformational changes on polymer surfaces is key to designing better biomedical devices.
• Biomedical polymers like polyurethanes and perfluorinated polymers are widely used.

Purpose of the Study:

• To investigate the adsorption behavior and conformational changes of fibrinogen on different biomedical polymer surfaces.
• To compare the sensitivity of attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and sum frequency generation vibrational spectroscopy (SFG) in detecting these changes.

Main Methods:

• Adsorption of fibrinogen onto two biomedical polyurethanes and a perfluorinated polymer.
• Analysis of fibrinogen's secondary structure changes using ATR-FTIR and SFG spectroscopy.
• SFG measurements focused on the amide I and C-H/N-H stretching ranges.

Main Results:

• SFG amide I signals indicated post-adsorption conformational changes in fibrinogen dependent on polymer surface properties.
• Fibrinogen adsorbed to poly(ether urethane) showed significant attenuation of amide I and N-H stretching signals over time, unlike on the other polymers.
• These specific spectral changes were not readily detected by ATR-FTIR.

Conclusions:

• Fibrinogen exhibits surface-dependent conformational changes upon adsorption to biomedical polymers.
• SFG spectroscopy is more sensitive than ATR-FTIR for detecting subtle, time-dependent structural alterations in adsorbed fibrinogen.
• Differences in binding mechanisms and conformational changes explain the varied spectral responses across different polymer surfaces.