Nanoscale engineering of low-fouling surfaces through polydopamine immobilisation of zwitterionic peptidesElectronic supplementary information (ESI) available: AFM images of scratched PDA and PDA/peptide films, XPS characterisation of PDA-coated and PDA/peptide-coated substrates, contact angles of films formed on various substrates, and quantitative E. coli and S. epidermidis adhesion onto glass/PDA/PEG substrates after incubation for 24 h. See DOI: 10.1039/c3sm53056f

We report a versatile approach for the design of substrate-independent low-fouling surfaces via mussel-inspired immobilisation of zwitterionic peptides. Using mussel-inspired polydopamine (PDA) coatings, zwitterionic glutamic acid- and lysine-based peptides were immobilised on various substrates, including noble metals, metal oxides, polymers, and semiconductors. The variation of surface chemistry and surface wettability upon surface treatment was monitored with X-ray photoelectron spectroscopy (XPS) and water contact angle measurements. Following peptide immobilisation, the surfaces became more hydrophilic due to the strong surface hydration compared with PDA-coated surfaces. The peptide-functionalised surfaces showed resistance to human blood serum adsorption and also effectively prevented the adhesion of gram-negative and gram-positive bacteria ( i.e. , Escherichia coli and Staphylococcus epidermidis ) and mammalian cells ( i.e. , NIH 3T3 mouse embryonic fibroblast cells). The versatility of mussel-inspired chemistry combined with the unique biological nature and tunability of peptides allows for the design of low-fouling surfaces, making this a promising coating technique for various applications. Immobilization of zwitterionic peptides on polydopamine surfaces showed resistance to human blood serum adsorption and also effectively prevented the adhesion of gram-negative and gram-positive bacteria and mammalian cells.