Surface charge control for zwitterionic polymer brushes: Tailoring surface properties to antifouling applications

• Published in: Journal of colloid and interface science 2015-08, Vol.452, p.43-53
• Main Authors: Guo, Shanshan, Jańczewski, Dominik, Zhu, Xiaoying, Quintana, Robert, He, Tao, Neoh, Koon Gee
• Format: Article
• Language: English
• Subjects: Adsorption; Animals; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Antifouling; Bacterial Adhesion - drug effects; Biofouling - prevention & control; Cattle; Escherichia coli - drug effects; Escherichia coli - growth & development; Hydrogen-Ion Concentration; Methacrylates - chemistry; Methacrylates - pharmacology; Mixed charge; Muramidase - antagonists & inhibitors; Muramidase - chemistry; Polymer brushes; Polymerization; Serum Albumin, Bovine - antagonists & inhibitors; Serum Albumin, Bovine - chemistry; Silicon Dioxide - chemistry; Staphylococcus aureus - drug effects; Staphylococcus aureus - growth & development; Static Electricity; Surface charge; Surface Properties; Surface-initiated ATRP; Thermodynamics; Water - chemistry; Zeta potential
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2015.04.013

[Display omitted] Electrostatic interactions play an important role in adhesion phenomena particularly for biomacromolecules and microorganisms. Zero charge valence of zwitterions has been claimed as the key to their antifouling properties. However, due to the differences in the relative strength of their acid and base components, zwitterionic materials may not be charge neutral in aqueous environments. Thus, their charge on surfaces should be further adjusted for a specific pH environment, e.g. physiological pH typical in biomedical applications. Surface zeta potential for thin polymeric films composed of polysulfobetaine methacrylate (pSBMA) brushes is controlled through copolymerizing zwitterionic SBMA and cationic methacryloyloxyethyltrimethyl ammonium chloride (METAC) via surface-initiated atom transfer polymerization. Surface properties including zeta potential, roughness, free energy and thickness are measured and the antifouling performance of these surfaces is assessed. The zeta potential of pSBMA brushes is −40mV across a broad pH range. By adding 2% METAC, the zeta potential of pSBMA can be tuned to zero at physiological pH while minimally affecting other physicochemical properties including dry brush thickness, surface free energy and surface roughness. Surfaces with zero and negative zeta potential best resist fouling by bovine serum albumin, Escherichia coli and Staphylococcus aureus. Surfaces with zero zeta potential also reduce fouling by lysozyme more effectively than surfaces with negative and positive zeta potential.