Reduced protein adsorption on novel phospholipid polymers

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Surface Science

Background:

• Developing blood-compatible polymers is crucial for medical devices.
• Conventional polymers often trigger adverse blood reactions like clotting and protein adsorption.
• Phospholipid polymers offer a promising alternative due to their biomimetic structure.

Purpose of the Study:

• To synthesize and evaluate novel phospholipid polymers containing 2-methacryloyloxyethyl phosphorylcholine (MPC) units.
• To assess the blood compatibility of these MPC copolymers.
• To investigate the mechanism behind reduced protein adsorption on MPC polymer surfaces.

Main Methods:

• Synthesis of phospholipid polymers with varying MPC unit fractions.
• Evaluation of blood clotting, cell adhesion, and activation on polymer surfaces.
• Measurement of protein adsorption from human plasma.
• Analysis of water structure and free water fraction in hydrated polymers using thermal analysis.
• Assessment of protein conformation on polymer surfaces.

Main Results:

• MPC copolymers effectively delayed blood clotting and prevented blood cell adhesion/activation without anticoagulants.
• Protein adsorption from human plasma was significantly reduced on MPC copolymers, decreasing with higher MPC content.
• Hydrated MPC polymers exhibited a higher free water fraction compared to poly(2-hydroxyethyl methacrylate) (HEMA).
• Proteins adsorbed on MPC copolymers retained their native conformation, unlike those on poly(HEMA).

Conclusions:

• Phospholipid polymers with high free water fractions, like MPC copolymers, exhibit excellent blood compatibility.
• These polymers minimize protein adsorption and denaturation, crucial for preventing adverse biological responses.
• The biomimetic nature of MPC polymers, particularly their hydration properties, underlies their superior performance in blood-contacting applications.