Amphiphilic Alginate-Based Layer-by-Layer Coatings Exhibiting Resistance against Nonspecific Protein Adsorption and Marine Biofouling
Thuvarakhan Gnanasampanthan, Jana F. Karthäuser, Stephan Spöllmann, Robin Wanka, Hans-Werner Becker, Axel Rosenhahn
Abstract
Amphiphilic coatings are promising materials for fouling-release applications, especially when their building blocks are inexpensive, biodegradable, and readily accessible polysaccharides. Here, amphiphilic polysaccharides were fabricated by coupling hydrophobic pentafluoropropylamine (PFPA) to carboxylate groups of hydrophilic alginic acid, a natural biopolymer with high water-binding capacity. Layer-by-layer (LbL) coatings comprising unmodified or amphiphilic alginic acid (AA*) and polyethylenimine (PEI) were assembled to explore how different PFPA contents affect their physicochemical properties, resistance against nonspecific adsorption (NSA) of proteins, and antifouling activity against marine bacteria (Cobetia marina) and diatoms (Navicula perminuta). The amphiphilic multilayers, characterized through spectroscopic ellipsometry, water contact angle goniometry, elemental analysis, AFM, XPS, and SPR spectroscopy, showed similar or even higher swelling in water and exhibited higher resistance toward NSA of proteins and microfouling marine organisms than multilayers without fluoroalkyl groups.