Thermal denaturation of fibrinogen visualized by single-molecule atomic force microscopy

Area of Science:

• Biophysics
• Materials Science
• Biochemistry

Background:

• Fibrinogen denaturation is crucial in biology and medicine.
• Previous studies used bulk methods, limiting detailed structural insights.
• Understanding fibrinogen's response to different conditions is vital for biomaterial development.

Purpose of the Study:

• To investigate fibrinogen denaturation at the single-molecule level using atomic force microscopy (AFM).
• To differentiate the structural changes induced by thermal denaturation versus surface interactions.
• To provide high-resolution ultrastructural data on individual fibrinogen molecules.

Main Methods:

• High-resolution single-molecule atomic force microscopy (AFM).
• Studying fibrinogen molecules after thermal treatment (65°C and 90°C).
• Analyzing fibrinogen incubated on a modified graphite surface (GM-HOPG) for extended periods (10 min).

Main Results:

• Thermal denaturation (65°C, 90°C) produced varied shapes, including fibrillar and globular structures (monomers, small aggregates).
• Surface incubation (10 min on GM-HOPG) led to fibrillar structures preserving the native six-polypeptide chain organization.
• Combined thermal denaturation and surface interaction resulted in globular aggregates and dense fibrillar networks.

Conclusions:

• AFM provides novel, high-resolution insights into fibrinogen unfolding mechanisms under different stimuli.
• Distinct morphologies arise from thermal stress versus surface interactions.
• Findings enhance understanding for improved fibrinogen-based biomaterials and biomedical applications.