Conference Proceeding

Nanostructured electrodes for ultrasensitive electrochemical impedance detection of pathogens

Dr. Abebaw Jemere,
National Institute for Nanotechnology, Canada

Dr. Abebaw Jemere is a senior research officer at the National Institute for Nanotechnology (NINT), National Research Council Canada, Edmonton, Alberta. He obtained his Ph.D from the University of Alberta in 2003, specializing in microfabrication and miniaturization of analytical systems for bioanalytical applications. Prior to NINT, he worked at CMC Microsystems (Kingston, Ontario) and Advanced Integrated Microsystems (Edmonton, Alberta) as staff scientist developing microfluidics based protein processing chips interfaced with mass spectrometry for proteomics applications. Dr. Jemere’s current research interest lies at the intersection of micro/nanotechnology and bio-and environmental systems, particularly in the development of biosensors and lab-on-a-chip systems for chemical and biochemical analysis, in molecular self-assembly and the development of thin films for the separation and detection of small molecules. Dr. Jemere has published over 35 manuscripts in peer reviewed journals and conference proceedings, and holds 2 patents.

Nanotechnology has tremendous potential to enhance the performance of biosensors. The chemical, electronic, and optical properties of nanomaterials generally depend on both their dimensions and their morphology. A major advantage of using nanomaterials in biosensing is the number of bioreceptor molecules immobilized on the detector surface can be as low as a single molecule. As a result the number of analyte molecules required to generate a measurable signal could be just a few providing very low limits of detection. As a sensitive, non-destructive, and label-free detection method, electrochemicalimpedance spectroscopy (EIS) has recently received considerable attention for the characterization of electrical properties in biological interfaces. We self-assembled gold nanoparticles on gold electrodes to yield multi-layered molecular structures for sensitive pathogen detection and in situ regeneration of the sensor electrode. The use of molecular self-assembly and gold nanoparticles plus EIS detection rendered a detection limit of 30 virus particles/ml for adenovirus 5 and 100 cells/ml for E-coli 0157:H7. The gold nanoparticle sensor surface could be self-assembled and regenerated at least 30 times without losing analytical performance. We also fabricated indium tin oxide nanoporous electrodes, using the glancing angle deposition (GLAD) technique, for disposable and yet highly sensitive EIS detection of pathogens. GLAD utilizes oblique angle physical vapor deposition combined with precision substrate rotation to engineer nano-columns. The combination of nanotechnology and EIS is an attractive and powerful concept for future chemical and biological sensors research and integration in to lab-on-a-chip devices for field deployable sensors.

Published: 27 April 2017