Bacteria detection utilizing electrical conductivity

Real-time and specific detection of single bacterium remains a fundamental challenge and draws very much attention. Using test patterns composed of interdigitated Au-electrode arrays modified with antibody, the specific and quantitative detection of the electrical conductivity of a single Escherichia coli (E. coli, JM109) has been carried out in this work. The key is to ensure low background current of the antibody-modified test patterns before bacteria detection (< 0.7 pA in this case) and minimize the residual moisture or hydration after E. coli immobilization, such as via the use of 1-min bake at 50 degrees C prior to electrical measurement. This method holds great potential for future application in the real-time, specific, and quantitative bacterium detection down to a single bacterium cell. (c) 2008 Elsevier B.V. All rights reserved.