A novel cationic waterborne polyurethane coating modified by chitosan biguanide hydrochloride with application potential in medical catheters

This study reported the synthesis and properties of a new cationic waterborne polyurethane coating. In this work, a chitosan derivative, chitosan biguanide hydrochloride (CSGH), was synthesized, which was used as a blocking agent and cross-linking agent to participate in the copolymerization of waterborne polyurethane (WPU) and a bioactive ingredient to enhance the biocompatibility of the coating. FTIR results demonstrated the reaction of CSGH with WPU. Moreover, the particle size distribution of the emulsion and SEM results showed that CSGH and WPU were well integrated. Benefiting from the formation of the cross-linking network, the thermodynamic properties of the coating were significantly improved. Furthermore, due to adding 3 wt% CSGH, the water contact angle of the coating surface decreased from 97.01° to 69.30°, indicating that the coating surface changed from hydrophobic to hydrophilic. And a specific resistance to Staphylococcus aureus and Escherichia coli was exhibited without cytotoxicity, the resistance rates could reach 85% and 91% respectively. It is highlighted that this WPU-CSGH coating has great application potential in the field of medical interventional catheters.