Superior Biolubricant from a Species of Red Microalga

Abstract

The rheological properties of the sulfated polysaccharide of the red microalga Porphyridium sp., a heteropolymer with a molecular weight of 3-5 x 10(6) Da, indicated that this material might be an excellent candidate for lubrication applications: the viscosity of the polysaccharide is stable over a range of temperatures, pH values, and salinities. In this study, various rheological and lubricant properties of the polysaccharide were evaluated in comparison with those of a widely used biolubricant, hyaluronic acid. The viscosity of the Porphyridium sp. polysaccharide remained essentially unchanged in a temperature range of 25-70 degrees C. In tribology tests on a ball-on-flat ceramic pair, the values for the friction coefficient and wear rate for the pair lubricated with polysaccharide were remarkably lower than those for hyaluronic acid, especially at high loads. In a test on a steel ring/ultrahigh-molecular-weight polyethylene (UHMWPE) block pair, the wear tracks on the surface of the UHMWPE were more pronounced for hyaluronic acid than for the polysaccharide. Atomic force microscopy showed that the polysaccharide was effectively adsorbed onto mica surfaces, forming ultrathin coating layers in the nanometer range. As is required for biolubricant applications, the polysaccharide was not degraded by hyaluronidase. The stability of the Porphyridium sp. polysaccharide to heat and to hyaluronidase combined with its ability to reduce friction and wear indicate its potential as an advantageous biolubricant.

Bioactivity and Applications of Sulphated Polysaccharides from Marine Microalgae

“…Nevertheless, Arad et al [68] have proved the superior biolubricant power of sPS from Porphyridium . Exocellular sulphated polysaccharide of Porphyridium has already shown good lubrication ability due to its rheological characteristics [103].…”

“…Exocellular sulphated polysaccharide of Porphyridium has already shown good lubrication ability due to its rheological characteristics [103]. Arad and co-workers [68] prepared an experiment where the lubricating properties of sPS were compared to the most used hydrogel lubricant, hyaluronic acid. They simulated efforts of joints, both when walking and running, and found a better quality from the EPS from Porphyridium as its rheological characteristics showed to be stable at higher temperatures than most lubricants used, whose viscosity decreases along with a decrease of lubricity.…”

Development, properties and applications of high-performance biolubricants

“…Its effi ciency is due to the complex structure of cartilage combined with the synergetic actions of self-assembled structures formed by phospholipids and biomacromolecules. Another report describes the use of polysaccharide as a superior biolubricant (Arad et al ., 2006 ). In this study the rheological properties of a natural polymer, sulfated polysaccharide derived from red microalga indicate that it is an excellent lubricant under aqueous conditions.…”

Hydrodynamic effect on the superlubricity of phosphoric acid between ceramic and sapphire

“…Based on this concept, polyelectrolytes with polymer brush appearances were also found to possess a super-low friction coefficient when sliding in water [17]. The superlubricity of other liquids, including the mixture of glycerol and acid [18] and some biological mucilage [19,20], has also been reported in recent years. Unlike solid superlubricity, the mechanism of liquid superlubricity is still debated.…”