Design of a microscopic electrical impedance tomography system for 3D continuous non-destructive monitoring of tissue culture

BioMedical Engineering OnLine

Eun Jung Lee³  Hun Wi²  Alistair Lee McEwan¹  Adnan Farooq²  Harsh Sohal²  Eung Je Woo²  Jin Keun Seo³  Tong In Oh² 

[1] The School of Electrical and Information Engineering, University of Sydney, NSW2006 Sydney, Australia

[2] Department of Biomedical Engineering and Impedance Imaging Research Center, Kyung Hee University, 46-701 Yongin, Korea

[3] Department of Computational Science and Engineering, Yonsei University, 120-749 Seoul, South Korea

关键词: Projected image reconstruction algorithm;    Tissue culture monitoring;    Three-dimensional impedance image;    Electrical impedance tomography;    Label-free;    Non-destructive monitoring;   

Others  :  1084283
DOI  :  10.1186/1475-925X-13-142

 received in 2014-04-19, accepted in 2014-09-27,  发布年份 2014

【 摘 要 】

Background

Non-destructive continuous monitoring of regenerative tissue is required throughout the entire period of in vitro tissue culture. Microscopic electrical impedance tomography (micro-EIT) has the potential to monitor the physiological state of tissues by forming three-dimensional images of impedance changes in a non-destructive and label-free manner. We developed a new micro-EIT system and report on simulation and experimental results of its macroscopic model.

Methods

We propose a new micro-EIT system design using a cuboid sample container with separate current-driving and voltage sensing electrodes. The top is open for sample manipulations. We used nine gold-coated solid electrodes on each of two opposing sides of the container to produce multiple linearly independent internal current density distributions. The 360 voltage sensing electrodes were placed on the other sides and base to measure induced voltages. Instead of using an inverse solver with the least squares method, we used a projected image reconstruction algorithm based on a logarithm formulation to produce projected images. We intended to improve the quality and spatial resolution of the images by increasing the number of voltage measurements subject to a few injected current patterns. We evaluated the performance of the micro-EIT system with a macroscopic physical phantom.

Results

The signal-to-noise ratio of the developed micro-EIT system was 66 dB. Crosstalk was in the range of -110.8 to -90.04 dB. Three-dimensional images with consistent quality were reconstructed from physical phantom data over the entire domain. From numerical and experimental results, we estimate that at least 20 × 40 electrodes with 120 μm spacing are required to monitor the complex shape of ingrowth neotissue inside a scaffold with 300 μm pore.

Conclusion

The experimental results showed that the new micro-EIT system with a reduced set of injection current patterns and a large number of voltage sensing electrodes can be potentially used for tissue culture monitoring. Numerical simulations demonstrated that the spatial resolution could be improved to the scale required for tissue culture monitoring. Future challenges include manufacturing a bioreactor-compatible container with a dense array of electrodes and a larger number of measurement channels that are sensitive to the reduced voltage gradients expected at a smaller scale.

【 授权许可】

   
2014 Lee et al.; licensee BioMed Central Ltd.

【 图 表 】

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