Study On The Extraction And Isolation Of Artificial Joint Wear Debris Under Ultrasonic Irradiation

Extraction and isolation of artificial joint wear debris from lubricating fluid or orthopedic clinic in the synovial fluid is the primary problem of study artificial joints wear debris. As non-magnetic and non-metallic properties, extraction of wear debris in fault diagnosis has been a difficult thing. Especially, it’s difficult to separate nanoscale wear debris from the solvent because of the action of varieties forces in nanoscale. Based on the previous study of the characteristics of particle separation and various domestic and international documents, the experimental study and theoretical research of micro-nano-particle separation have been summarized systematically.Three separation methods such as acid digestion, alkali digestion and enzymatic degradation were used for extraction and separation of artificial joint wear debris-ultrahigh molecular weight polyethylene(UHMWPE).A filtration device was designed, and the law of micro-nano-powder filter by changing the pressure, filter series, solution concentration and membrane pore size was studied. During the experiment, powder agglomeration and stacking phenomenon were controlled.In order to study the extraction process by ultrasonic, based on the UHMWPE surface features and interface status, the force and movement process of UHMWPE were analyzed. Meanwhile, the relationship between acoustic parameters and separation process with MATLAB were studied. The results show that: certain size wear debris in the suitable frequency and sound power can be effectively separated. So a new idea for the artificial joints wear debris separation was provided. It is useful for the designation of experimental device and selection of subsequent.Optimized design of Ultrasound system was done in this study. Modal and harmonic analysis of vibration of the ultrasonic extraction device for the research by ANSYS analysis were finished. The horn parameters and machining dimensions were initially identified. An adjustable power ultrasound power was designed by ourselves, to solve the matching problem of ultrasonic generator or ultrasonic power.After study the existing equipment and test methods, the ultrasound system was improved to meet the micro-nano-scale particles separation test requirements. Micro-nano-scale particles ultrasonic separation device was developed to overcome the problem of micro-nano-scale particles deposition to accelerate the filtering progress.Wear debris ultrasonic extraction device matching with corresponding filter system containing membranes, cake, vacuum filtration system and collection system was developed. In order to achieve the classification of wear debris, scanning electron microscopy or other means were used to analyze the particle sizes. Lubricant was treated with artificial joint ultrasound testing machine. The degradation of bovine serum albumin, UHMWPE wear debris stripping from bovine serum with ultrasound, as well as structure of bovine serum albumin and aggregation of UHMWPE wear debris in lubricating fluid impacted by ultrasound were studied. The beneficial effect of artificial joints wear debris extracted by ultrasonic extraction device was verified.