Investigation of the friction induced conformational change of protein and wear of UHMWPE by a wear process with microfabricated surfaces

An accelerated wear testing procedure was developed to carry out an articulation process between UHWMPE and microfabricated surfaces with controlled asperities. By such a design, the effect of lubricant on wear of UHMWPE can be scaled-up and measured within a short duration of the test. The most abundant composition of the synovial fluid-human serum albumin was employed as a lubricant. Analysis of the albumin protein structure by a circular dichroism (CD) spectroscopy was proceeded to detect the conformational change during a tribological process. We observed that the thinner and fibril-like wear particles were found in biological lubricants than the particle generated in water. Our results also indicated that the content of α-helix structure of albumin was decreased after the tribological process. The denatured albumin solution resulted in the decrease of UHMWPE wear rate. It may be due to the decrease of the contact angle of unfolding albumin protein on articulating surfaces. It implies a larger coverage of the lubricating molecules on the UHMWPE surface. The relevance of the tribological process induced conformational change and wear of UHWMPE were discussed in this study.