Amphiphilic Polysaccharides as Inert Surface Coatings

Stella Bauer,^1,2 Maria Pilar Arpa Sancet,^1,2 John Finlay,³ Maureen Callow,³ James Callow,³ Nick Aldred,⁴ Anthony Clare⁴ and A.Rosenhahn^1,2

¹ Institute of Functional Interfaces, IFG, Karlsruhe Institute of Technology, Germany

² Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Germany

³ School of Biosciences, University of Birmingham, United Kingdom

⁴ School of Marine Science and Technology, Newcastle University, United Kingdom

Biofouling, the unwanted adhesion of macromolecules and growth of organisms on manmade surfaces is an economical and ecological challenge for modern surface research.¹ The potential of polysaccharides for fouling-resistant coatings lies in their chemical structure: due to the presence of hydroxyl-groups, they are highly hydropihilic and able to form water-storing hydrogels. Their resistance against bacteria and mammalian cells was e.g. demonstrated by Morra and Cassinelli.² Cao et. al.³ applied these materials to the marine environment and showed that different acidic polysaccharides have a high anti-fouling potential in terms of protein resistance, but loose this promising property in the marine environment. This collapse is caused by a complexation of bivalent cations like Ca²⁺.⁴ In this study, the free carboxyl-groups of two polysaccharides, hyaluronic acid (HA) and chondroitin sulfate (CS) were postmodified with the hydrophobic amine 2,2,2-trifluoroethylamine (TFEA). With this strategy, different intentions could be realized: a blocking of free carboxyl groups to prevent complexation of ions and a preservation of the resistance in marine environment, a shifting of the contact angle towards the minimum in the Baier curve to maximize inert properties⁵ and the introduction of amphiphilic properties due to the hydrophobic fluoro-groups.⁶ Subsequently, the coatings were tested towards their protein resistance and different fouling relevant species to evaluate their resistance properties.

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