Surface characterization and platelet adhesion studies on polyethylene surface with hirudin immobilization

Area of Science:

• Biomaterials Science
• Biochemistry
• Surface Chemistry

Background:

• Hirudin is a potent anticoagulant and thrombin inhibitor.
• Thrombus formation is a critical concern in biomaterial applications.
• Surface modification of polyethylene (PE) is essential for improving biocompatibility.

Purpose of the Study:

• To covalently immobilize hirudin onto a chromic acid-oxidized polyethylene surface.
• To evaluate the effect of hirudin immobilization on platelet adhesion.
• To investigate the surface chemistry changes induced by oxidation and immobilization.

Main Methods:

• Polyethylene (PE) surface oxidation using chromic acid.
• Covalent immobilization of hirudin using water-soluble carbodiimide.
• Surface analysis using ESCA (Electron Spectroscopy for Chemical Analysis).
• In vitro platelet adhesion assays.

Main Results:

• Chromic acid oxidation generated carboxylic acid groups and roughened the PE surface.
• Hirudin immobilization was consistent across studied reaction times.
• Oxidized PE showed increased platelet adhesion, while hirudin-immobilized surfaces showed significantly reduced adhesion compared to oxidized PE.
• Reduced platelet adhesion on hirudin-coated surfaces is attributed to the hirudin-thrombin complex and altered adsorbed protein composition.

Conclusions:

• Covalent immobilization of hirudin onto oxidized PE surfaces is feasible.
• Hirudin immobilization effectively reduces platelet adhesion on PE surfaces.
• This approach holds promise for developing antithrombotic biomaterials.