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.
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.
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.
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.