Fabrication of Resistive E. coli Biosensor Based on ZnO Nanorods and Nanoparticles

In this paper, a biosensor has been fabricated using ZnO nanorods and nanoparticles to detect different concentrations of the E. coli bacteria. The innovation of this paper lies in design and fabrication of the resistive type E Coli bacteria sensor. To make this biosensors, printed circuit board based electrodes are designed and made in an interdigitated shape. Both hydrothermal and drop cast methods have been used to grow zinc oxide nanorods and to form a layer of zinc oxide nanoparticles on copper electrodes, respectively. By using these biosensors, different concentrations of the E. coli bacteria in water are measured. When the sensor is in contact to the bacteria, the resistance is changed because of reactions with the zinc oxide. The biosensor output is provided as a voltage proportional to the resistance change between the interdigitated electrodes. The results have been measured for biosensors exposed to UV light. The effect of zinc oxide nanoparticles concentration and PCB dimensions on voltage and sensitivity of the biosensors are also investigated. The measurement results using the fabricated biosensors have been compared and the biosensor with the highest sensitivity has been introduced.