Formation and tribology of fucoidan/chitosan polyelectrolyte multilayers on PDMS substrates. (December 2017)

• Record Type: Journal Article
• Authors: Ho, Tracey T.M.; Selway, Nichola; Krasowska, Marta; Yakubov, Gleb E.; Stokes, Jason R.; Beattie, David A.
• Is Part Of: Biotribology. Volume 12(2017)
• Page Start: 15
• Page End: 23
• Publication Date: 2017-12
• Subjects: Polyelectrolyte multilayer -- Fucoidan -- Chitosan -- PDMS -- Lubrication; Biological interfaces -- Periodicals; Biomedical materials -- Periodicals; Biomechanics -- Periodicals; Tribology -- Periodicals; 610.2805
• DOI: 10.1016/j.biotri.2017.04.002
• Languages: English
• ISSNs: 2352-5738

Abstract

Abstract: Polysaccharide polyelectrolyte multilayers (PEMs) based on fucoidan and chitosan were formed by Layer-by-Layer (LbL) assembly on polydimethylsiloxane (PDMS) substrates. The surface and aqueous lubrication properties of the PEM films are evaluated for two types of fucoidan extracted from separate seaweed species ( Fucus vesiculosus – FV and Undaria pinnatifida – UP). Zeta potential and atomic force microscopy (AFM) imaging reveal that the PEM layers are formed with consistent charge reversal as each polysaccharide layer is adsorbed to the PDMS substrate, and that there is an associated increase in thickness of the multilayer. The multilayers containing FV fucoidan are found to be thicker than those containing UP fucoidan. Soft tribology measurements using matching PDMS tribo-pairs are used to show that the films are robust under rolling/sliding contacts and effective under aqueous lubricating conditions. The friction in the boundary lubrication regime is substantially decreased (relative to native hydrophobic PDMS) by the presence of the multilayers, with some dependence on whether fucoidan or chitosan is in the outer layer (5 or 5.5 bilayers) for FV fucoidan. The lowest friction coefficient is obtained for the multilayer with the thickest (and likely most hydrated) coating – the (FV/chitosan) 5.5 bilayer system. The results suggest that PEMs involving naturally derived polysaccharides such as fucoidan, which has notable antimicrobial properties and is resistant to enzymatic degradation, may provide opportunities in surface coating design in biomaterials applications for friction reduction. Graphical abstract: Highlights: Natural polysaccharide polyelectrolyte multilayer lubricant formed on soft PDMS substrates using fucoidan and chitosan Zeta potential determination and AFM confirm the sequential build-up of the lubricant (layer-by-layer). Friction-reducing properties studied using soft tribology measurements, revealing effective aqueous lubrication Thickness (and assumed higher hydration) seen to be more important for reduction of friction