Functionality and stability of heparin immobilized onto poly(dimethylsiloxane)

Area of Science:

• Biomaterials Science
• Microfluidics Engineering
• Surface Chemistry

Background:

• Poly(dimethylsiloxane) (PDMS) is widely used in microfluidics due to its rapid prototyping capabilities.
• The high surface-to-volume ratio in microchannels necessitates careful consideration of material-sample interactions, especially for biological fluids like blood and plasma.
• Controlling surface properties is crucial for preventing unwanted reactions, such as coagulation, within microfluidic systems.

Purpose of the Study:

• To develop and evaluate a novel non-covalent heparin surface modification for PDMS.
• To impart efficient anticoagulant properties to PDMS materials for microfluidic applications.
• To assess the stability and functionality of the heparin coating in microchannels.

Main Methods:

• A simple, one-step, neutral pH surface modification process was employed to immobilize heparin onto hydrophobic PDMS.
• The antithrombin-binding capacity of the heparin coating was quantified.
• Plasma coagulation assays were performed on native and heparin-coated PDMS over a three-week period.

Main Results:

• A uniform and functional heparin coating was successfully achieved on PDMS.
• The modified PDMS exhibited a high level of antithrombin-binding capacity.
• Plasma incubated on native PDMS showed complete coagulation within 1 hour, while heparin-coated PDMS prevented fibrin formation.
• The heparin coating demonstrated stability in microchannels for up to three weeks.

Conclusions:

• The developed heparin coating provides effective anticoagulant properties to PDMS.
• This surface modification is a valuable tool for utilizing PDMS in microfluidic systems handling blood or plasma.
• The simple, one-step process is suitable for closed microsystem applications.