Biological lubricants are essential for the effective functioning of biomedical systems that involve relative motion. Hyaluronic acid (HA) is often used for its excellent lubrication properties; however, its long-term effectiveness is compromised by its tendency to accelerate metal corrosion. Incorporating cellulose nanocrystals (CNCs) into HA offers a promising solution due to CNCs' corrosion-inhibition properties, tunable rheological behavior, and tribological properties. This study examines the impact of varying HA and CNC concentrations on friction, wear, and corrosion in HA/CNC suspensions. Optimal performance was achieved with 2 wt% CNC in 1 mg/mL HA, corresponding to the onset of gelation. Below this CNC concentration, lubrication improves through the formation of a protective film and the mitigation of corrosion. Increasing CNC beyond 2 wt% yields minimal additional benefit. HA concentration also plays a key role: at low HA levels, corrosion predominates, leading to increased friction and wear. In contrast, HA levels above 1 mg/mL in 2 wt% CNC suspensions enhance lubricant film formation due to improved rheology, resulting in reduced wear, coefficient of friction, and corrosion. These results underscore the importance of optimizing HA and CNC concentrations to maximize their synergistic effects in advanced bio-tribological lubrication applications.
Bose et al. (Thu,) studied this question.