Phospholipid Vesicles in Media for Tribological Studies against Live Cartilage

Abstract

Introduction Pre-clinical testing of hemiarthroplasty devices requires that the tribological conditions present in vivo with live cartilage be closely duplicated. A current limitation in the tribological testing of live cartilage involves the use of cell-culture media as lubricant. Study Aim to develop and test a new hyaluronan-phospholipid based medium (HA–phospholipid medium) that combines the rheological and frictional properties of synovial fluid with the nourishing properties of culture media to keep cells alive. Materials and Methods The HA–phospholipid medium consisted of culture medium with added phospholipid dipalmitoylphosphatidylcholine (0.3 mg/mL), and hyaluronic acid (2.42 mg/mL). A standard cell culture medium was used as the control. The rheology of each medium was determined using a flat plate configuration. Bovine calf cartilage was used to assess cell viability and friction in each medium. For friction measurements, a cobalt-chrome alloy ball was articulated against cartilage disks immersed in medium. Results Lipid vesicles 0.1 to 50 μm in diameter were identified in the HA–phospholipid medium. Cartilage cell viability was significantly higher in the HA–phospholipid medium (62% ± 8%, 95% CI) than in control medium (49.5% ± 5%) (p = 0.009). The HA–phospholipid medium exhibited strong shear-thinning behavior, similar to synovial fluid, with viscosities ~100-fold higher at 10 s−1 and 5-fold higher at 20,000 s−1 than the approximately Newtonian control medium. The HA–phospholipid medium also yielded 20% lower friction values than the control medium after one hour of testing. Conclusions The rheological and friction results indicate that the HA–phospholipid medium is superior to the control cell culture medium in emulating the shear thinning and lubricative properties of natural synovial fluid, making it more clinically relevant for in vitro wear and friction testing with live cartilage.

The Role of Hyaluronic Acid in Cartilage Boundary Lubrication

“…In the hydration lubrication paradigm surfaces interact via fluid but tenaciously attached hydration layers exposed by their boundary layers at the slip plane, resulting in low friction as surfaces slide past each other [ 12 , 58 ]. Previous studies [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 56 , 59 , 60 , 61 , 62 , 63 , 64 ] showed that HA interacts with PC lipids when they are dispersed in aqueous solution or when the phospholipids are incubated with pre-adsorbed HA on a surface, due to charge-dipole interactions between the negatively charged HA and the exposed zwitterionic phosphocholine headgroups. Thus one would expect that HA would adsorb at a phospholipid-bilayer/water interface.…”

The Implication of Reactive Oxygen Species and Antioxidants in Knee Osteoarthritis

“…In recent years, functional metal oxide nanosystems have been developed to transport agents of natural [ 182 ] or synthetic antioxidants [ 178 ]. The most efficient nanosystems were made up of soft nanoparticles, such as polymeric micelles [ 183 ], nanoemulsions [ 184 ], and lipid vesicles [ 185 ].…”

Interactions between hyaluronic acid and CoCrMo alloy surface in simulated synovial fluids

“…With regard to the fluid viscosity, any addition of HA is certainly associated with an increase in fluid viscosity. Based on published viscosity measurements on simulated synovial fluids [20, 32], the viscosity of DPBS + HA is approximately 10 times higher than the viscosity of DPBS. The mobility of ions ‘ u ’ is inversely proportional to the fluid viscosity (4) [22]: where ‘ z ’ is the magnitude of the ion's charge, ‘ e ’ the electronic charge, ‘ η ’ the fluid viscosity, and ‘ r ’ the ion's radius.…”