Antifouling coatings based on zwitterionic
polymers have been widely applied for surface modification of interventional blood-contacting devices to combat
thrombosis and
infection. However, the weak adhesion stability of the zwitterionic coating to the device surface is still the key challenge. In this work, biocompatible mixed-charge zwitterionic
polyurethane (MPU)
polymers, that bear equal amounts of cationic quaternary
amine groups and anionic carboxyl groups, were developed and further uniformly dip-coated onto a thermoplastic
polyurethane (TPU) substrate with a commercial aliphatic
isocyanate cross-linker (AIC). During the curing process, AIC not only crosslinks MPU chains into a
polymer network but also reacts with
hydroxyl groups of TPU to interlink the
polymer network to the substrate, resulting in a cross-linking reinforced MPU coating (
CMPU) with excellent mechanical robustness and adhesion strength. Taking advantage of the mixed-charge feature, the final zwitterionic
CMPU coating exhibits both excellent antifouling and antibacterial activities against
protein adsorption and bacterial growth, respectively, which is beneficial for effectively inhibiting the occurrence of in vivo
infection. Moreover, anticoagulation studies show that
CMPU-coated TPU
catheters can also prevent the formation of
blood clots in ex vivo rabbit blood circuits without
anticoagulants. Hence, the designed
CMPU coating has immense potential to address
thrombosis and
infection for interventional blood-contacting devices.