Bioimpedance

Bioimpedance is a physiological property related to how electrical current flows through tissues of a living organism. It is specifically defined as the resistance the tissue poses to electrical current flow and the ability tissue has to store electrical charge. The Halter Lab is developing medical technologies so clinicians can better detect, diagnose, stage, treat, and monitor patients with a variety of pathologies. We are not only working to get these new technologies into the hands of clinicians. We are also using basic science and engineering aspects to better understand the biology influencing the electrical properties of tissue, as well as designing techniques to accurately gauge these properties.

We are developing bench-to-bedside technologies to develop clinical applications for bioimpedance in the following three research areas:

Biophysics of Bioimpedance: Exploring and quantifying the available electrical property contrast between tissues types and pathologies and developing, testing, and modeling hypotheses that describe the underlying biophysical mechanisms responsible for this contrast.
Bioimpedance Technology Development: Developing technologies, instrumentation, and computational infrastructure to accurately gauge and image these electrical properties.
Clinical Applications of Bioimpedance: Leveraging the knowledge gained from understanding contrast levels and mechanisms and the instrumentation designed and constructed to integrate these technologies into the clinical environment.

What is impedance?

Impedance is the ratio between voltage and current. It describes the total opposition of a circuit to AC or DC signals. In our lab, we typically perform experiments with current carrying electrodes (CC) and voltage pick-up electrodes (PU).

Bioimpedance is the ability of a tissue, or other biological material, to resist current flow. Tissue can be regarded as a dielectric. From literature, it has been shown that different tissue types and conditions show characteristic values at certain frequencies.

Using what we know about the relationship between impedance and electrical relationships, we can also calculate the resistance, reactance, and even conductivity.

What is the difference between EIS and EIT?

Electrical impedance spectroscopy is one way to apply impedance where measurements are taken across a spectrum of frequencies with the same electrodes. At low frequencies, we are able to collect information about the area surrounding cells. At high frequencies, the signals travel through cells giving information about the internal cellular properties.

Electrical Impedance Tomography is also capable of taking measurements at a spectrum of frequencies. The main difference is that EIT requires significantly more electrodes. By taking measurements with numerous combinations of electrodes, we can eventually create a map of the material under measurement.

EIT - Electrical Impedance Tomography

Our lab applies EIT in different ways! Check out the People tab to learn more about how our lab members work with EIT.

Sadaf T. Dr. Murphy Sophie L. Allaire D. Zenia V.

ECIS - Electrical Cellular Impedance Spectroscopy

This is the application of impedance to study cellular or other microscale components.

Read more about Riley F. and Mimi L. whose research covers this area.

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