An N-substituted polyurea coating with high affinity for heparin

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Biocompatibility Engineering

Background:

• Biomaterial surface modification is crucial for improving hemocompatibility.
• Existing materials often face challenges with protein adsorption, platelet adhesion, and immune responses.
• Heparinization is a common strategy to enhance blood compatibility.

Purpose of the Study:

• To synthesize and characterize a new N-substituted polyurea with tertiary amino groups (NPUTA).
• To evaluate the efficacy of NPUTA coatings for heparin immobilization on various biomaterials.
• To assess the in vitro and in vivo biocompatibility of NPUTA-heparin modified surfaces.

Main Methods:

• Synthesis and characterization of NPUTA polymer.
• Coating of biomaterials (polyurethanes, charcoal hemosorbents, hemodialysis membranes) with NPUTA.
• Heparin adsorption and release studies.
• In vitro assays: protein adsorption, platelet adhesion, hemolysis, complement activation.
• In vivo studies: calcification in a rat subcutaneous implant model.

Main Results:

• NPUTA exhibits high water uptake and adhesion to polar substrates.
• NPUTA-coated surfaces effectively adsorb and retain significant amounts of heparin.
• NPUTA/heparin modification significantly reduces platelet adhesion and complement activation.
• Modified surfaces show improved in vitro blood compatibility without compromising functional properties (e.g., middle molecule sorption).
• NPUTA/heparin treated bovine pericardium demonstrated reduced calcification in vivo.

Conclusions:

• NPUTA is a promising polymer for creating heparin-releasing coatings on biomaterials.
• NPUTA-heparin surfaces enhance blood compatibility by minimizing thrombotic and inflammatory responses.
• This modification strategy offers a versatile approach to improve the performance of various medical devices and implants.