One superlubricant in the human body is the synovial fluid. It is a complex fluid comprised of a high molecular weight polysaccharide, hyaluronic acid (HA), and a globule protein, lubricin. It encompasses aspects of a boundary layer lubricant as well as a hydrodynamic lubricant. HA creates a highly viscouselastic network able to adsorbs large amounts of energy; Lubricin prevents surface contact by means of a “ball-bearing” effect. One of the debilitating effects of Osteoarthritis is a decrease in the elasticity of synovial fluid. A common remedy is to inject the joint with aqueous solutions of HA. However, this is a short-term solution. This research explores the possibly enhancing these HA solutions through the addition of micron sized hydrogel particles based on poly(N-isopropylacrylamide) (PNIPAM). Various concentration of PNIPAM hydrogel particles and HA were explored using bulk measurements on a cone-and-plate rheometer. This presentation will show that suspensions of HA and PNIPAM hydrogel particles can be successfully tune to have comparable rheological properties to synovial fluid.
