Detection of highly sensitive Escherichia coli (E. coli) bacteria using an electrochemical sensor based on zinc oxide/polyvinyl alcohol nanocomposite

Escherichia coli (E. coli) bacteria is found in various water and food sources, posing a significant threat to human health by potentially causing several diseases. Therefore, this study aimed to explore the fabrication of electrochemical sensor based on ZnO/PVA nanocomposite. The fabrication was carried out using a screen-printed carbon electrode (SPCE), with ZnO/PVA nanocomposite serving as a modifying material on the working electrode through the drop-casting method. ZnO/PVA nanocomposite was characterized using Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD), I-V, and cyclic voltammetry electrochemistry. The results of FESEM characterization showed an even distribution of ZnO in PVA matrix with an average of 59 nm particle size. The modification of the working electrode with ZnO/ PVA nanocomposite showed an improved current response. Furthermore, a response time of approximately 3-5 min was achieved with a limit of detection (LOD) of 1.97 x 106 CFU during E. coli detection testing. This phenomenon enabled the prototype sensor to detect the presence of E. coli, shown by an increase in current generated during cyclic voltammetry testing. Based on the potential for further development, electrochemical sensor based on ZnO/PVA nanocomposite showed promise in becoming a leading option for E. coli detection.