In Vivo Mechanical Characterization of Micro-Specimens Using a Novel Micro-Electro-Mechanical System

Mechanical probing, stimulation and characterization of tissues are of the most challenging areas of engineering due to limitations of working with bio specimens. Understanding the bio-mechanics of tissues could potentially help to understand mechanical degradation of biological tissues due to disease or change in physiological condition of the body. Biomechanical processes at the microscopic level have become increasingly recognized as an important factor in different biological conditions. In many of these conditions analyzing biomechanics of tissues at microscale in vivo or in vitro will provide invaluable information on microenvironment and physiological parameters that affect the microenvironment and mechanical properties. To address the issue of measuring mechanical properties at microscale, an electroactive-based micro-electromechanical machine is designed. The device is comprised of two electroactive (piezoelectric) micro-elements mounted on a rigid frame. Electrical activation of one of the elements causes it to expand and induce a stress in the intervening micro-specimen. The response of the microspecimen to the stress is measured by the deformation and thereby voltage/resistance induced in the second electro-active element. Figure 1 shows the device design and architecture. Analytical analysis and multiphysics finite element analysis (FEA) are used to prove the concept. A summary of the results are shown in the next sections.