Synthesis, characterization and cytocompatibility of polyurethaneurea elastomers with designed elastase sensitivity.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Tissue Engineering

Background:

• Designing synthetic scaffolds for soft tissue engineering requires materials with elasticity, cell compatibility, processability, and in vivo remodeling capacity.
• Existing materials often lack a combination of mechanical strength, controlled degradation, and bioactivity.

Purpose of the Study:

• To develop and characterize a novel family of polyurethaneureas (PUs) with enzymatic remodeling capabilities for soft tissue engineering applications.
• To evaluate the mechanical properties, hydrolytic and enzymatic degradation, and cell adhesion characteristics of these PUs.

Main Methods:

• Polyurethaneureas (PUs) were synthesized using polycaprolactone or PCL-PEG-PCL as soft segments, 1,4-butanediisocyanate as the hard segment, and Ala-Ala-Lys as a chain extender.
• Mechanical properties (tensile strength, breaking strain) and thermal properties (glass transition temperature) were assessed.
• In vitro degradation studies were performed in buffered saline with and without elastase.
• Surface modification with Arg-Gly-Asp-Ser (RGDS) was achieved via radio frequency glow discharge.
• Endothelial cell adhesion was quantified on pristine and modified PU surfaces.

Main Results:

• Synthesized PUs exhibited high molecular weights, low glass transition temperatures (< -54°C), high flexibility (670-890% strain), and significant tensile strength (15-28 MPa).
• PUs showed controlled hydrolytic degradation (12-18% mass loss over 8 weeks) and significantly enhanced degradation in the presence of elastase (19-34% mass loss).
• Degradation products were non-cytotoxic, and surface modification with RGDS increased endothelial cell adhesion by over 200% compared to tissue culture polystyrene.

Conclusions:

• The developed polyurethaneureas possess a unique combination of mechanical robustness, tunable enzymatic degradability, and enhanced cell interactivity.
• These PUs show significant potential as versatile scaffolds for soft tissue engineering, facilitating cell integration and tissue remodeling.
• The material's properties can be tailored by adjusting the soft segment composition for specific regenerative medicine applications.