WHY don’t your eyelids get stuck to your cornea? And what makes cartilage so slippery that your knees can bend smoothly? Some clues may lie in what happens when a pair of “molecular hairbrushes” get soaking wet.
Water-based solutions lubricate our joints and prevent them wearing out, but how they do this is a mystery, says Jacob Klein, a physicist specialising in the properties of soft matter at the University of Oxford and the Weizmann Institute of Science in Israel. Water alone is not viscous enough to be a good lubricant.
A polysaccharide called hyaluronan has long been thought to…
