Electronic Sensing Systems for Next Generation SDS PAGE Technologies

This document presents an assessment on the viability of an electronically measured, miniaturised alternative to “sodium dodecyl sulphate polyacrylamide gel electrophoresis”, abbreviated as SDS-PAGE or simply Gel Electrophoresis. An understanding of alternating electrical fields and its effects on dielectrics with and without the presence of ionic substances suggests that a capacitive electrode could be used as a sensor in detecting the motion of ions under a large external electrostatic field. Photolithography was used to manufacture small scale interdigitated capacitor loops to be used in conjunction with a sensor holder to measure effects of varying electric field strength on the motion of salt ions through agarose gel. The polarity of the electric field was also reversed to determine whether the process of ionic motion was reversible. The sensor was capable of measuring the gradual introduction of salt ions through the gel but unsuccessful in reversing the process of ionic measurement. A second double mesh experiment was also conducted to enable salt ions to pass through the sensor in order to detect the possibility of a peak and then reduction of voltage readings. This experiment also studied the effects of varying salt concentration and showed a higher voltage reading for higher salt concentrations as well as a slightly faster transition time when an electric field was present compared to the absence of a field however was unable to record a drop of voltage after 24 hours.