Platelet adhesion and activation on a shielded plasma gradient prepared on polyethylene

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Hemocompatibility

Background:

• Blood contact with foreign materials can trigger thrombogenic responses, influenced by biomaterial surface wettability.
• Existing gradient surfaces have limited ranges due to preparation methods like diffusion or density immersion.

Purpose of the Study:

• To develop a novel method for creating polymer gradient surfaces with a wide wettability range.
• To investigate the impact of varying surface wettability on platelet adhesion and activation, and subsequent blood clotting.

Main Methods:

• Utilized glow discharge with partial shielding to create polymer gradient surfaces over a 5 cm length.
• Characterized surface properties using water contact angle measurements and Electron Spectroscopy for Chemical Analysis (ESCA).
• Incubated gradient surface sections with anticoagulated whole human blood to study platelet-surface interactions and clotting activation.

Main Results:

• Generated polyethylene gradient surfaces with advancing water contact angles from 90° to 40° and hysteresis of 30°.
• ESCA confirmed increased oxygen incorporation towards the hydrophilic end of the gradient.
• Fewer platelets adhered to hydrophobic ends, but exhibited higher activation (morphology, GpIIb-IIIa exposure).
• Hydrophilic ends showed increased platelet adhesion and the highest overall clotting activation.

Conclusions:

• The glow discharge technique enables the creation of large-range wettability gradients, facilitating detailed studies of blood elements.
• Platelet activation is more pronounced on hydrophobic polyethylene surfaces.
• Moderate hydrophilic polyethylene surfaces lead to increased platelet adhesion and activation of the blood clotting system.