Solid-medium-integrated impedimetric biosensor for real-time monitoring of microorganisms

Rapid, real-time detection of pathogenic microorganisms is an emerging and quickly evolving field of research, especially with regard to microorganisms that pose a major threat to public health. Herein, a new method that uses bioimpedance and solid culture medium for the real-time monitoring of bacterial growth is introduced. We fabricated a new impedimetric biosensor by integrating solid medium and two plane electrodes attached on two facing sides of an acryl well, during bioelectrical impedance analysis, the solid medium showed the characteristics of a homogenous conductive material. In a real-time impedance measurement, our solid medium biosensor could monitor bacterial growth in situ with a detection time of similar to 4 h. We applied different culture media (e.g. Tryptic Soy Agar, Luria Agar, and Nutrient Agar) to our biosensor and found that a low conductive medium was optimal for the monitoring of the bacterial growth due to low threshold in the variation of the impedance signal. Our data indicate that the solid medium biosensor is useful for detection of pathogenic microorganisms, thereby providing a new analytical tool for impedance microbiology. (C) 2009 Elsevier B.V. All rights reserved.