Atomic force microscopy studies of the initial interactions between fibrinogen and surfaces

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Biophysics

Background:

• Understanding protein-surface interactions is crucial for biomaterial development.
• Surface wettability is a key factor influencing protein adhesion and conformational changes.
• Atomic force microscopy (AFM) offers high-resolution insights into these interactions.

Purpose of the Study:

• To investigate the influence of surface wettability on fibrinogen adhesion and unfolding.
• To analyze the energy landscapes governing protein-surface interactions.
• To correlate surface properties with protein conformational dynamics.

Main Methods:

• Utilized atomic force microscopy (AFM) with a novel experimental setup.
• Proteins were immobilized on substrates, and model surface colloids were attached to the AFM probe.
• Analyzed adhesion forces, loading rates, and contact time-dependent adhesion data.

Main Results:

• Fibrinogen exhibited similar adhesion forces across highly wettable surfaces and similarly across poorly wettable surfaces, with a distinct transition between the two groups.
• Protein interactions with poorly wettable surfaces displayed multiple energy barriers, while highly wettable surfaces showed a single energy barrier.
• Protein unfolding rate constants were lower on highly wettable surfaces at low loading rates but increased significantly at high loading rates.

Conclusions:

• Surface wettability critically modulates fibrinogen adhesion forces and energy landscapes.
• The observed differences in energy barriers and unfolding kinetics highlight the role of wettability in protein conformational changes.
• These findings provide valuable insights into protein behavior at biomaterial interfaces, impacting biomaterial design and function.