Electrical Impedance Tomography With a Lab‐on‐Chip for Imaging Cells in Culture

Abstract

Electrical Impedance Tomography (EIT) is a non-invasive, non-ionizing, and inexpensive imaging modality that is used to image the conductivity distribution inside the subject under test. EIT is an emerging imaging technique that has the potential to be used in a variety of (bio)medical applications. A technology that is easy to integrate into a small portable device and also easy to setup. In this work a custom made impedance analyzer is used as a measurement device. The working principle is based on the different conductivity distributions of the material under test, this due to inhomogeneous bioelectrical properties. However there is one major downside of this technique, the reconstruction problem of EIT is severely ill-posed. This means that the definition of a correct model is essential. Because of this ill-posed condition, a comparison of different models is done. In this work, an in depth study is performed to achieve the most optimal way of solving the inverse problem, which leads to noise suppression and reproducible results. This technology, integrated in a lab-on-chip for monitoring cellular growth, is based on a spatial reconstructed imaging technique using electrical impedance tomography.

Fully printed, stretchable and wearable bioimpedance sensor on textiles for tomography

“…EIT image reconstruction is a technique that gives the possibility to reconstruct the electrical conductivity distribution of a closed domain in a conductive medium based on the surface potential generated at the boundaries on injecting a known current signal. To do this, different measurement patterns available were studied [36].…”

“…A lot of different methods for current injection and measuring patterns are described for electrical impedance tomography, but up till now, there is no consensus on what the ideal method is. In previous work, the adjacent method, the opposite method and the opposite driving/adjacent measuring method were compared to determine the best method for our setup and goal [36]. Based on visual interpretation, the adjacent method performed the most consistent and thus is the method of choice.…”

“…The electrodes were printed on the fabric without a planarizing layer and their sheet resistance is measured (four prob Van Der Paw method) in the range of 0.065-0.1 Ωsquare. These electrodes were connected to the EIT measurement setup [35] through printed conductive tracks. An insulation layer was printed on top of the tracks to reduce the noise distortions in the EIT image.…”

3D Image Reconstruction Capability of Peripheral On-chip ECT Sensor

“…In recent decade, the miniaturisation of electrical tomography sensor array has been blooming with the advancement of microfluidics and lab-on-chip applications. The electrical impedance tomography (EIT) sensor array for example, has been miniaturised to fit in miniature sensing chamber of sizes ranging from 12 mm to 35 mm and the size of microelectrodes ranges from 0.6 mm to 5 mm [13], [14], [15], [16]. The miniature EIT sensors has been investigated in 3D imaging of cells [17], 2D visualisation of drug responds on cells in scaffolds [18] and 3D imaging of 3D cultured cells in scaffold [13].…”