Gemini quaternary ammonium salt waterborne biodegradable polyurethanes with antibacterial and biocompatible properties

In this study, a series of waterborne biodegradable polyurethanes with antibacterial and biocompatible properties were developed. To obtain these polyurethanes, lysine-derivative gemini quaternary ammonium salt (GQAS) chain extenders with different hydrophobic alkyl chain lengths (named EGn, where n = 8, 12, 16; the hydrophobic alkyl chain length of GQAS) were designed and synthesized. Then, waterborne biodegradable polyurethanes (PCLPUn) were prepared using isophorone diisocyanate (IPDI), poly(ε-caprolactone) (PCL), poly(ethylene glycol) (PEG), L-lysine and EGn. The antibacterial activities of these EGn and PCLPUn emulsions were evaluated by a minimal inhibitory concentration (MIC) method, and the antibacterial and antifouling functionalities of the PCLPUn film surfaces were confirmed by a contact-active antibacterial and culture-based method using both Gram-positive and Gram-negative bacteria. The in vitro degradation and cytotoxicity of these obtained polyurethanes were also systematically investigated. These results indicated that the PCLPUn films possessed good antibacterial and antifouling abilities, biodegradability, and good biocompatibility. Notably, PCLPU12 shows the best antibacterial activity and cytocompatibility. Such antibacterial materials could be degraded to non-toxic components, and potentially be widely used in medical and environmental applications, especially as biodegradable coatings of surgical equipment and medical implants.