AbstractBio-impedance spectroscopy has been increasingly used for medical and food industrial applications as it provides information about cellular structure, composition and integrity of cell membranes of biological samples. This study is focused on analysing how bio-impedance spectrum is affected by cellular structure (cell deformation, shape and orientation) and the integrity of cell membranes during the frozen-thaw injury process. Two measurement systems were designed and built: contact-electrode measurement and non-contact induction measurement system. For the former, the frequency range of measurement is 10 kHz to 10 MHz while the frequency range for the latter is 400 kHz to 6 MHz. Both systems can detect the change in impedance spectrum of biological samples (potato and meat) caused by the poration of the cell membranes during the frozen-thaw injury process. A finite element method (FEM) simulation solver was built and applied for the simulation of BIS. Specifically, the poration of the cell membrane was simulated and it was proved to cause the increase in equivalent conductivity of the cell membrane and this is in agreement with the experimental observation carried out in this thesis work and previous studies reported in literature. The shape and orientation effect of the cell was also simulated and the results were explained with physical insights. In addition, a new acceleration method for simulating thin cell membrane based on FEM was proposed and implemented. The modelling method accelerates the computing progress by reducing the number of meshing elements without reducing the accuracy of the simulation in a significant manner in comparison with analytical solutions. The accuracy of the acceleration modelling (reduced-mesh model) was also validated by the full-meshed FEM model to be within 0.4%-2% while the simulation time was reduced up to 25%.
|Date of Award||31 Dec 2020|
|Supervisor||Anthony Peyton (Supervisor) & Wuliang Yin (Supervisor)|
- finite element method
- bio-impedance spectroscopy
- non-contact induction measurement
- frozen-thaw effect