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

The issue of determining the mechanical properties of vascular walls and atherosclerotic plaques constantly arises during numerical modeling of vascular bed sections. Testing machines, as a rule, are located in special laboratories outside medical institutions, and transporting samples from the clinic is associated with certain difficulties. Thus, the task of developing mobile testing devices that can be installed directly in the clinic for testing immediately after surgery is urgent. This article presents the results of the development and testing of a mobile test bench for performing mechanical experiments on uniaxial compression and stretching of biological tissues. The purpose of the stand is to conduct mechanical tests in the clinic with fresh tissues in order to avoid their transportation to the laboratory and/or freezing. The Arduino UNO application platform is used as a control element in the stand, which monitors the main elements of the stand (motor, load cell), as well as recording data to an SD card and displaying information about the experiment on a computer screen. Structurally, the stand is an analog of a two-column testing machine. All the mechanisms are assembled in a portable suitcase, the control module is made in the form of an external plastic box. The stand was verified on the basis of a universal Instron 3342 machine with a 500 N load cell. A total of 121 experiments on soft tissues (including arterial walls and atherosclerotic plaques) were conducted using the stand. The obtained Young's modulus and strength limits are summarized in a table. The average Young's modulus for the wall of the internal carotid artery was 0.32 ± 0.24 MPa, for a soft plaque 0.30 ± 0.17 MPa, for a hard plaque 0.85 ± 0.39 MPa; for hard plaques in the carotid arteries, a strength limit of 1.12 ± 0.67 MPa was also determined. As a result, a unique database of Young modules obtained from freshly collected material was compiled. The methodology and its implementation on the mobile stand show a good correlation with the literature data for all types of materials studied.