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Abstract Ti15Mo alloy has been regarded as one of the most potential biomedical materials due to its excellent performance. However, the low hardness and poor wear resistance of titanium alloy limit the further application. Therefore, high temperature solid carburising technology was performed on the surface of Ti15Mo alloys to prepare titanium carbide (TiC) coating with graphene (G) as the carburising agent. The microstructure, mechanical properties, and tribological properties of TiC coating under different lubricants were investigated. Results showed that TiC coating was closely bonded to the titanium substrate. The maximum thickness of TiC coating treated with 1150°C was approximately 184.02 μm, and the microhardness of alloys treated with 1100°C can achieve 1221.5 HV. All modified Ti15Mo alloys showed improved tribological performance compared to the original samples. The wear mechanisms of modified Ti15Mo alloys were abrasive wear and adhesive wear under the SBF lubricant, and the TiC coating was slightly peeled off. The overall friction coefficient and wear rate under 25% calf serum lubricant were lower than the SBF lubricant, and surface scratches were almost absent, and slight abrasive wear and adhesive wear occurred on the surface.

Abstract Experimental in vitro simulation can be used to predict the wear performance of total knee replacements. The in vitro simulation should aim to replicate the in vivo loading, motion and environment experienced by the joint, predicting wear and potential failure whilst minimising test artefacts. Experimental wear simulation can be sensitive to environmental conditions; the environment temperature is one variable which should be controlled and was the focus of this investigation. In this study, the wear of an all‐polymer (PEEK‐OPTIMA™ polymer‐on‐UHMWPE) total knee replacement and a conventional cobalt chrome‐on‐UHMWPE implant of similar initial surface topography and geometry were investigated under elevated temperature conditions. The wear was compared to a previous study of the same implants under simulator running temperature (i.e. without heating the test environment). Under elevated temperature conditions, the wear rate of the UHMWPE tibial inserts was low against both femoral component materials (mean

Abstract Slippage is a common phenomenon between laparoscopic graspers and tissues during minimally invasive surgery, which may lead to inefficient surgical operations, prolonged operation time, and increased patient suffering. The stability factors related to the friction behaviour between laparoscopic graspers and the large intestine, including bio‐surface liquids, pulling angle, and surface profile of graspers, were studied. The friction behaviour at the large intestine–grasper interface was tested using a UMT‐II tribometer under the conditions of clamping force of 1–4 N, sliding displacement of 15 mm, and sliding velocity of 2 mm/s to simulate the grasping and pulling operations of soft tissue. The results showed that the bio‐surface liquid (serum) of the large intestine significantly decreased the friction coefficient, thus reducing the grasping efficiency. A pulling angle of 15° could generate the peak frictional force and enhance the grasping stability. The frictional force increased with the ratio of the profile surface area of the grasper. These results demonstrate that the grasping stability can be improved by changing either the bio‐surface liquid condition or the pulling angle. In addition, a grasper with a larger profile surface area can also prevent slippage due to its significant influence on the pressure distribution and actual contact area for tissue retention.

This paper presents a brief synopsis of work on relationships between mammalian tooth form and function, and considers the role of dental wear in studies of mammal teeth. Mammalian teeth function both as guides for chewing and as tools for initiating and propagating cracks through food items. They tend to vary in form and structure with the mechanical properties of foods a species has evolved to eat; and we can learn a lot about relationships between teeth and diet by comparing species. One area of special interest is tooth wear. Dental structure and chemistry combine in ways that lead wear to sculpt occlusal surfaces so a tooth can develop or maintain its functional efficiency. Dental wear, especially that on microscopic scales, can also serve as a proxy for diet in fossil species, as specific types of food leave distinctive patterns.

To develop a novel biotribological material for artificial cartilage implant with a lubricity supplement of the joint surface, we focused on two types of poly(vinyl alcohol) (PVA) hydrogel: repeated freeze–thawing (PVA-FT) and cast-drying (PVA-CD) gels. Here we observed the morphology of wear particles generated during a reciprocating wear test and assessed macrophage immune responses by applying hydrogel wear particles. As a result, PVA-CD had a significantly lower total amount of wear than did PVA-FT. The size distributions of PVA-FT and -CD wear particles were similar. Most of the particles were nanoparticles up to approximately 50 nm in diameter. Considering the particle volume distribution, there were very few micron- and submicron-sized wear particles around 1 μm in diameter. In SEM observations of dried PVA wear particles, both distributions of wear particles of PVA-FT and -CD were similar. Micron-sized wear particles were chiefly formed by close packing of 20- to 50-nm-sized particles. Biochemical and immunological evaluations revealed no cytotoxic effects of wear particles on macrophages. Cytokine synthesis of both wear particle-stimulated groups was significantly lower than that of the lipopolysaccharide-stimulated positive control. Therefore, it is suggested that PVA wear particles do not affect the macrophage immune response.

Biotribology deals with all aspects of tribology concerned with biological systems. It is one of the most exciting and rapidly growing areas of tribology. It is recognised as one of the most important considerations in many biological systems as to the understanding of how our natural systems work as well as how diseases are developed and how medical interventions should be applied. Tribological studies associated with biological systems are reviewed in this paper. A brief history, classification as well as current focuses on biotribology research are analysed according to typical papers from selected journals and presentations from a number of important conferences in this area. Progress in joint tribology, skin tribology and oral tribology as well as other representative biological systems is presented. Some remarks are drawn and prospects are discussed.