Thermoplastic polyurethanes for biomedical application: A synthetic, mechanical, antibacterial, and cytotoxic study

Thermoplastic polyurethanes (TPUs) bear tunable chemistry offering the possibility to develop a rich palette of physio-mechanical properties, making the materials suitable for various fields of application. The great variety in TPUs properties comes from the choices of the monomers and the reaction conditions. Herein, the mechanical properties of the developed TPUs are tailored, while fine-tuning the hard and soft segment molar ratio, as well as the reaction conditions. TPUs are synthesized from 4,4 '-methylenebis(phenyl isocyanate), poly(tetrahydrofuran), and 1,4-butanediol, and their thermal and mechanical properties are fully characterized. The sample with the most appropriate mechanical properties that are suitable for catheter fabrication, is selected for the biomedical application. Quaternary ammonium salt is synthesized, and 0.5 mol% is incorporated in the TPU to confer antibacterial properties to the material while preserving its mechanical strength. The microbiological tests reveal the antibacterial effect of the developed materials against Staphylococcus aureus and Pseudomonas aeruginosa, as well as 80% SiHa cell viability, after 72 h of exposure, as part of the performed cytotoxicity studies. Finally, TPUs catheter prototypes fabrication is also proposed, applying an extrusion or injection molding approach for the production of biomedical devices with desirable mechanical properties.