Tribological investigation of diamond-like carbon coated micro-dimpled surface under bovine serum and osteoarthritis oriented synovial fluid

Abstract

Osteoarthritis-oriented synovial fluid (OASF), i.e., that typical of a patient with osteoarthritis, has different physical and biological characteristics than bovine serum (BS), a lubricant widely used in biotribological investigations. Micro-dimpled and diamond-like carbon- (DLC) coated surfaces are key emerging interfaces for orthopedic implants. In this study, tribological performances of dimpled surfaces, with and without DLC coating, have been investigated under both BS and OASF. The friction tests were performed utilizing a pin on a disk tribometer, whereas contact pressure, speed, and temperature were simulated to a ‘medium walking gait’ of hip joint conditions. The mechanical properties of the specimen and the physical properties of the lubricant were characterized before the friction test. Raman analysis was conducted to identify the coating condition both before and after the test. The DLC-coated dimpled surface showed maximum hardness and residual stress. A DLC-coated dimpled surface under an OASF lubricated condition yielded a lower friction coefficient and wear compared to those of plain and dimpled specimens. The higher graphitization of coated materials with increasing load was confirmed by Raman spectroscopy.

Tribological performance of the biological components of synovial fluid in artificial joint implants

“…Usually, high friction causes more wear on contact surfaces [20, 39]. However, there are many other factors related to the wear mechanism.…”

“…Our systematic search of tribological behaviors of biological components of synovial fluid [6] also pointed out that the number of studies in this area is comparatively low, and therefore, more research should be conducted in this area. Our recent study [20] on advanced interfaces revealed the better tribological performances under OA-oriented synovial fluid compared to bovine serum. This study focused on modification of surface properties where titanium alloy was used as a bulk material.…”

An Overview on the Tribological Performance of Titanium Alloys with Surface Modifications for Biomedical Applications

“…The dimples can store and release the lubricant under the loading conditions which lead to a decrease in the sliding contact and wear rate. By contrast, Ghosh et al [47] found that textured surfaces cannot create a suitable wear resistance under high loads. An improved tribological behavior was seen in a simulated body fluid than in water even at higher loads.…”

“…The presence of water-soluble macromolecules is responsible for the hydrophilic nature of the cartilage. The fluid film formation, generated by the hydrophilic macromolecules, decrease the friction in the joints [45][46][47][48][49]. There are two general grafting methods: "grafting to" and "grafting from".…”

“…The wear rate at 15 N load was 7.66 × 10 −12 m 3 /Nm of plasma treated alloy and 1.27 × 10 −11 m 3 /Nm of the untreated one [63]. Ghosh et al [47] grafted poly (2-methacryloyloxyethyl phosphorylcholine) (PMPC) on Ti-6Al-4V alloy by selective laser melting. Three different techniques (ultraviolet (UV) irradiation, thermal heating, and UV irradiation by N 2 gas) were applied during the tests and the results showed a great performance for N 2 gas because of existing oxygen in the atmosphere which prevented the polymerization.…”