Contact-active antibacterial surfaces play a vital role in preventing bacterial contamination of artificial surfaces. In the past, numerous researches have been focused on antibacterial surfaces comprising of antifouling upper-layer and antibacterial sub-layer. In this work, we demonstrate a reversed surface structure which integrate antibacterial upper-layer and antifouling sub-layer. These surfaces are prepared by simply casting gemini quaternary ammonium salt waterborne polyurethanes (GWPU) and their blends. Due to the high interfacial energy of gemini quaternary ammonium salt (GQAS), chain segments containing GQAS can accumulate at polymer/air interface to form an antibacterial upper-layer spontaneously during the film formation. Meanwhile, the soft segments composed of polyethylene glycol (PEG) formed the antifouling sub-layer. Our findings indicate that the combination of antibacterial upper-layer and antifouling sub-layer endow these surfaces strong, long-lasting antifouling and contact-active antibacterial properties, with a more than 99.99% killing efficiency against both gram-positive and gram-negative bacteria attached to them.

Light-crosslinking waterborne polyurethanes (LWPUs) based on lysine possess appropriate elasticity for soft tissue repair, and can induce macrophages into a wound healing phenotype.

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.