Facile and Rapid Detection of Pathogenic Bacteria Using Immuno-Magnetophoretic Assay

Harmful pathogenic bacteria provoke various diseases such as food poisoning, and they are becoming a major public health issue. Since micro-organisms can easily proliferate over time, the rapid detection of bacteria at early stage is desired to prevent food poisoning. We have developed a novel immunomagnetic flow assay for the facile and rapid detection of pathogenic bacteria. A type of pathogenic bacteria, Salmonella typhimurium were captured by antibody-functionalized magnetic nanoparticle clusters (AbMNCs), and they were magnetically separated in a cylindrical microchannel. Approximately 99% of AbMNCs-Salmonella complexes capture rate was achieved under the high flow rate by stacked permanent magnets with certain gap distance between each magnet which maximized the magnetic force. The resulting concentration of the bacteria was determined by ATP luminescence measurements. The detection limit was better than 10 cfu/mL and the overall assay time for 1 mL sample took less than 30 minutes. To our knowledge, our 3D immunomagnetic flow assay is the first demonstration of rapid and facile detecting method for pathogenic bacteria with high sensitivity, which has a great potential to revolutionize the food inspection processes.