A Rapid and Ultra-sensitive Sensing Strategy based on Tunable Dielectrophoresis for Robust POC Detection

Sensitive and specific detection of pathogenic bacteria was important for early and appropriate antibiotic treatment of infected humans and animals. Also, the detection of Gram-negative bacteria, such as Escherichia, had a significant implication in food safety as the organisms were a major cause of food-borne illnesses. Our previous studies demonstrated that dielectrophoretic (DEP) capacitive sensing could be used to accelerate the detection by simultaneous DEP attraction of target bioparticles to the sensor surface and direct monitoring of interfacial capacitance. In this report, we implemented stepwise voltages for the detection of Gram-negative bacteria with high sensitivity and selectivity. The sensor achieved a detection limit of 282.1 cells/mL and a dynamic range of 282.1~2.82×104 cells/mL. The tunable dielectrophoresis approach is applicable for improved detection of other bioparticles.