Rapid Bacteria Detection at Low Concentrations UsingSequential Immunomagnetic Separation and Paper-Based Isotachophoresis

Detecting bacteria is important in the fields of human health, environmental monitoring, and food safety. Foodborne pathogens alone are estimated to cause 420 000 deaths annually, with low-income regions affected most. Despite improvements in bacterial detection, fast, disposable, low-cost, sensitive, and user-friendly methods are still needed. Traditional methods for detecting bacteria rely primarily on cell culturing or polymerase chain reaction (PCR), which require highly trained personnel and a central laboratory and take several hours or even days to deliver results. Low-cost methods like lateral flow immunoassays exist but frequently suffer from poor sensitivity and/or lack quantitative results. Here, a rapid method for detecting bacteria at very low concentrations is presented using two sequential preconcentration steps. In the first preconcentration step, the sample is mixed with antibody-modified magnetic particles and free antibodies conjugated to β-galactosidase (β-gal). The target bacteria are...