Development of A Point-of-Use Testing Platform for Detecting Bacteria Infection in Raw Milk

The detection and quantification of bacteria are essential to environment and food quality monitoring. Escherichia coli (E. coli) is a common pathogen, also a causative agent of mastitis. Traditional methods usually require samples to be tested in a laboratory. However, sending samples to remote lab increases the cost of time and money spent on delivery. Sometimes, samples can degrade during this long progress and cause inaccuracy. A low cost and reusable sensor is designed to perform on-site quantification. The sensor composed of two layers of asymmetrical mesh electrodes, which is used in coordination magnetic microparticles functionalized with bacterium-specific antibody. Immunological binding between the bacteria and its antibody is utilized to identify the target. The sensor can selectively detect coagulated clusters of bacteria and magnetic microparticles, which is based on negative dielectrophoresis and alternating current electrothermal microflows. A hypothesis is proposed and experimentally validated to explain the sensing mechanism, which is used to improve the detection sensitivity. Further, a compact and embedded testing kit (aceTeK) is developed to help perform point-of-use testing and diagnosis. Data is acquired, processed, and analyzed to yield a conclusion about the existence of any bacteria infection in the milk.