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, bio-inspired 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 mussel-inspired 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 (QCM-D) 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 light-guided targeting and releasing of drug delivery and molecular imaging.