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

## TL;DR

Researchers developed a new thermoplastic polyurethane with amino acid-based components and clay, showing strong mechanical and antibacterial properties for soft tissue repair.

## Contribution

A novel thermoplastic polyurethane with l-lysine diisocyanate and functionalized clay is introduced, offering enhanced mechanical and antibacterial properties.

## Key findings

- The optimal TPU has a Young's modulus of 0.19 MPa and elongation at break of 2375%.
- Adding 3 wt% clay increases Young's modulus by up to 26 times and provides antibacterial efficacy against Gram-positive and Gram-negative bacteria.
- TPU fibers show higher tensile strength than bulk TPU while maintaining high elongation at break.

## Abstract

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.