A polyurethane-based hydrophilic elastomer with multi-biological functions for small-diameter vascular grafts

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Vascular Engineering

Background:

• Small-diameter vascular grafts face challenges from thrombosis and intimal hyperplasia (IH).
• Mimicking native endothelium and vessel elasticity is crucial for graft success.
• Polyurethane (PU) offers mechanical suitability but lacks biofunctionality and hydrophilicity.

Purpose of the Study:

• To develop a hydrophilic PU elastomer with endothelium-like biofunctions and elasticity for small-diameter vascular grafts.
• To address the limitations of current PU materials in vascular applications.

Main Methods:

• Synthesized a hydrophilic PU elastomer by crosslinking hydrophobic hard-segment chains (containing diselenide) with diaminopyrimidine-capped polyethylene glycol (PEG).
• Investigated underwater elasticity through hydration-induced stiffening, tunable by crosslinking density.
• Evaluated in vitro biological functions (nitric oxide release, anti-platelet/SMC activity, antibacterial effect) and in vivo biocompatibility.

Main Results:

• The PU elastomer exhibited tailored elasticity similar to natural vessels.
• Demonstrated multi-biological functions mimicking the endothelium, including nitric oxide release, anti-thrombotic, anti-proliferative, and antibacterial properties.
• In vivo studies showed good histocompatibility with reduced immune response and calcium deposition.

Conclusions:

• The developed hydrophilic PU elastomer successfully integrates mechanical properties, hydrophilicity, and endothelium-like biofunctions.
• This material shows significant potential for constructing small-diameter vascular grafts, mitigating thrombosis and intimal hyperplasia.
• The study highlights a promising strategy for bulk modification of implantable materials.