Integrative Graduate Education and Research Training (IGERT)

ProBING THE SKIN USING MICROELECTROMECHANICAL SYSTEMS (mEMS) APPLICATION

As depicted through science fiction movies and novels, medical diagnostics and surgeries are preformed with in-vivo tools.  In a fictional scenario, the human body is scanned either by a hand- held device or a full body scanner.  Depending on the diagnostic tool utilized, a computer interface processes and detects any anomalies. Then, corrective treatment is used to eliminate or compensate for any anomaly(s). Today, the health care industry strives for efficiency and fast diagnostic responses. In this respect, the future of medical technology is aiming for non-invasive medical instrumentations. Currently, a portable hand-held device, the SonoPrep Skin Permeation device, allows for non-invasive transdermal diagnostic and drug delivery through the stratum corneum. It is manufactured by Sontra Medical Corporation. Research on the electrical properties of the skin has been investigated since the early 1900s.  This paper will present nine various electrode systems which validate and promote diagnostic measurements based on electrical properties from the skin.

The skin’s electrical properties can include capacitance, conductivity, resistance, and impedance. Impedance is defined as a complex quantity (phasor voltage per phasor current).   The skin is electrically modeled by a resistor in parallel with a capacitor. The resistor represents the extracellular and intracellular fluid of the cell. Likewise, the capacitor represents the cell membrane’s capacitance. Electrode systems have been designed to extrapolate information from the skin. These systems are based on the fundamental theory of electrical fields. Few techniques used to collect data are electroporation, electrical capacitance, and electrical impedance. The relevant studies are discussed in the following paragraphs.