Dielectrophoresis-based microwire biosensor for rapid detection of Escherichia coli K-12 in ground beef

Abstract

By combining a functionalized microwire sensor with a dielectrophoresis (DEP) technique, a rapid and accurate detection method for bacterial pathogens was developed and demonstrated. The gold-tungsten microsensor (sensing diameter, 25 μm) was functionalized with specific Escherichia coli (E. coli) antibodies against surface antigens to capture E. coli bacterial cells from phosphate buffer saline (PBS) and ground beef. The DEP technique consisted of the application of a pin-type microwire and large base electrode under an alternating current (AC) electric field of 10 Vpp at a frequency of 3 MHz. Additionally, bovine serum albumin (BSA) was utilized as a blocking agent for the attachment of nonspecific proteins to the microwire surface to prevent false positive signals due to nonspecific binding. The resistance and fluorescent intensity (FI) demonstrated a linear relationship with the concentration of E. coli cells ranging from 103 to 107 CFU/mL. These results showed that DEP can be used as a reliable alternative for the detection of E. coli without a blocking effect minimizing the significant difference between PBS and ground beef.