Introduction: Articular cartilage is among the most effectively lubricated system in nature, with friction coefficients as low as 0.001 under physiological pressures, which are up to 100 atm or higher. The excellent friction, wear and load bearing capacity of articular cartilage have been attributed to the special structure and synovial fluid according to many researches, especially the bottle-brush macromolecules or similar to those like hyaluronan, lubricin and aggrecan presented at the outer surfaces and synovial fluid. The lubrication properties of those brushes have attracted considerable interest recently. However, at physiological state, as the clinical biolubricant, hyaluronan solution viscosity drops nearly to values similar to those of water, which leads to limited benefits when inject the hyaluronan to relief the pain of osteoarthritis. So, a novel bionic synovial fluid is always needed to improve the friction and wear property of degenerated cartilage or prosthesis. Materials and Methods: Adipic dihydrazide (ADH) was used to aminate Hyaluronan (HA, 1000-1500 kDa) to obtain HA-ADH, poly (2-Acryloylamino-2-methyl-1-propanesulfonic acid) (PAMPS) was prepared by reversible addition-fragmentation chain transfer polymerization, the novel bottle-brush polyelectrolyte (HA-g-PAMPS) was then obtained by the amidation between HA-ADH and PAMPS. The cytotoxicity and apoptosis were estimated by bone marrow mesenchymal stem cells (BMSCs) using WST assay and LDH assay. The lubricating ability was characterized by Bruker UMT-2. Results and Discussion: HA-g-ADH was characterized by 1H-NMR and FT-IR, which conformed the successful synthesis. HA-g-PAMPS dissolved in culture medium did not caused a large number of apoptosis, which showed a good cell compatibility in Fiugre1a and 1 b. Low concentration of the solution had a bit inhibition of cell proliferation, but the higher concentration solutions did not show that. The macromolecules dissolved in PBS and culture medium by 5mg/ml applied in two friction pairs, which were used to simulate artificial and natural joints. As shown in Figure 1c and 1d, macromolecules solutions can significantly reduce the friction coefficient, especially when they were in culture medium. It was indicated that the HA-g-PAMPS had a synergistic effect with the proteins in medium, which was similar to the natural synovial fluid. Conclusion: A novel bottle-brush polyelectrolyte was prepared successfully, and showed no cytotoxicity according to cell proliferation and apoptosis. Importantly, it also showed excellent lubricity, which revealed the polyelectrolyte can be applied as a potential novel bionic lubricant used in cartilage repair or prosthesis.
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