Development and approval of a mobile test bench for the study of the mechanical properties of biological tissues

Abstract

The determination of the mechanical properties of vessel walls and atherosclerotic plaques is a recurring issue in the numerical modelling of vessel sections. Testing machines are usually located in specialised laboratories outside medical facilities, and transporting samples from the clinic is difficult. Therefore, the task of developing mobile testing devices that can be installed directly in the clinic to perform tests immediately after surgery is relevant. This paper presents the results of the development and validation of a mobile test bench for performing mechanical experiments on uniaxial compression and tension of biological tissues. The purpose of the work is to perform mechanical tests on tissues in the clinic, avoiding their transport to the laboratory and/or freezing. Arduino UNO hardware platform is used as the control element of the test bench, which controls the main elements (motor, load cell), records data on SD card and displays information about the experiment on the computer screen. Structurally, the test bench is an analogue of a two-column testing machine. All mechanisms are assembled in a portable case, the control module is in the form of a remote plastic box. Verification of the test bench was carried out using an Instron 3342 universal testing machine with a 500 N load cell. A total of 121 soft tissue tests (including arterial wall and atherosclerotic plaque) were performed on the bench. The Young's modulus and ultimate strength values obtained are summarised in a table. The mean Young's modulus for the wall of the internal carotid artery was 0.32 ± 0.24 MPa, for soft plaque 0.30 ± 0.17 MPa, and for hard plaque 0.85 ± 0.39 MPa; a tensile strength of 1.12 ± 0.67 MPa was also determined for hard plaques in carotid arteries. The result is a unique database of tissue Young's moduli obtained from freshly collected material. The methodology and its implementation on the mobile test bench show good agreement with literature data.