(521f) Impedance Sensing with Micro- and Nanoscale Metallic Elements for Chemical Detection

Many surface events such as adsorption/desorption, surface binding and modification can cause impedance variation of the substrates, especially for those consisting of micro- and nanoscale elements. Therefore impedimetric sensing may be a promising way to develop low-cost, label-free and portable devices for chemical detection and point-of-care diagnostics. Interests in our lab have focused on fabrication of micro- and nanoscale metallic elements and their applications for chemical and biomolecular sensing. We have successfully fabricated regenerable bimetallic atom-scale junctions (such as Au-Ag-Au and Au-Cu-Au) by electrochemical methods both on open Si chip surface and in PDMS microfluidic channels. More stable metallic nanowires have also been fabricated by several different ways on Si and a comparative study of their electrical and chemical sensing properties has been carried out. In addition, we have fabricated microscale interdigitated electrode arrays on insulating substrates such as glass and used them as the impedimetric sensing elements to monitor changes in intracellular physiology of immobilized cells caused by toxins in water.