Functional surfaces with zwitterionic carboxybetaine L-3,4-dihydroxyphenylalanine: Synthesis, coating, and antifouling applications

In this paper, we present synthesis of a novel carboxybetaine L-3,4-dihydroxyphenylalanine derivative (CBDOPA) and its excellent antifouling properties to inhibit bacterial adhesion. We optimized the coating efficiency by controlling oxidation-induced polymerization with various oxidants in an alkaline environment. The surface coating was investigated by water contact angle goniometry, ellipsometry, X-ray photoelectron spectroscopy, atomic force microscopy, and FT-IR spectroscopy. Among the conditions examined, the optimal condition was the sodium periodate-mediated oxidation, which achieved the highest CB-DOPA coating efficiency. The optimized CB-DOPA coating was applied to a variety of substrates, including gold, titanium dioxide, stainless steel, poly(tetrafluoroethylene), and polyurethane. Compared with bare controls, CB-DOPA-coated substrates showed high resistance to the adhesion of Escherichia coli.