Synthesis and Characterization of Biomimetic Thermoplastic Polyurethanes and Nanocomposites with l -Lysine Diisocyanate

Biomimetic materials are of significant interest in applications such as soft tissue repair, with their ability to replicate morphology and properties of native tissue. This study reports a novel thermoplastic polyurethane (TPU) synthesized with an amino acid-based diisocyanate hard segment. The effects of hard segment percentage on the mechanical, thermal, and hydrophilic properties were assessed. The optimal TPU shows a Young's modulus of 0.19 MPa, a tensile strength of 0.61 MPa, and an elongation at break of 2375%. Incorporating a novel functionalized clay in this TPU gives excellent antibacterial properties, demonstrating efficacy against both Gram-positive and Gram-negative bacterial strains. The addition of this clay also significantly enhances the mechanical properties of the TPU, with Young's modulus increasing by up to 26 times with 3 wt % clay. The TPU was spun into fibers, creating a fibrous scaffold mimicking the architecture of some soft tissues. The TPU fibers exhibit a considerably higher tensile strength compared to bulk TPU while maintaining a high elongation at break. These TPUs and TPU-clay nanocomposites may find potential applications in soft tissue scaffolds or patches with antibacterial or anti-inflammatory behavior, for example, for the repair of gastrointestinal tissue that may be exposed to harmful bacteria.