Novel bio-inspired zwitterion dopamine molecule for anti-biofouling and photocleavable properties

Use of synthetic biomaterials as blood-contacting devices typically accompanies considerable nonspecific adsorption of proteins, cells and bacteria. These may eventually induce adverse pathogenic problems in clinic practices, such as thrombosis and biomaterials-associated infection. An effective surface coating for medical devices has been pursued to repel nonspecific adsorption from surfaces. In this study, bioinspired adhesive dopamine conjugated with zwitterionic sulfobetaine moieties (SB-DA) was developed for anti-biofouling properties. The molecules can anchor onto various substrates via catechol groups to form a stable thin film. The results indicated that the formation of self-assembled monolayers (SAMs) was strongly dependent on the pH values in preparation, which correlates to the oxidization and reduction (redox) of catechol groups in dopamine molecules. The Other musselinspired catecholic zwitterionic nitro-sulfobetaine moieties (SB-nDA) assembly possessing antifouling and photocleavable characters for spatiotemporal tailoring of interfacial properties and controlling bio-adsorption. X-ray photoelectron spectroscopy (XPS) was used to analyze the bonding mechanism, accounting for distinct wetting and fouling levels from contact angle and quartz crystal microbalance with dissipation (QCMD) measurements. The thickness simulation from XPS and ellipsometry showed about 1.1 nm for intact SB-DA films and 1.03 nm for intact SB-nDA. In addition, the bacterial test indicated the excellent resistance of films against P. aeruginosa. This work provides not only new surface chemistry but the new route for surface modification. Currently, SB-DA is applied onto various materials with different dimensions as a new generation of self-assembling biomaterials for a wide spectrum of applications then SB-nDA for potential applications in lightguided targeting and releasing of drug delivery and molecular imaging.