Magnetophoretic chromatography for the detection of pathogenic bacteria with the naked eye

A facile and sensitive analytical method that uses gold-coated magnetic nanoparticle clusters (Au/MNCs) and magnetophoretic chromatography with a precision pipet has been developed for the detection of Salmonella bacteria. Antibody-conjugated Au/MNCs are used to capture the Salmonella bacteria in milk and are then separated from the milk by applying an external magnetic field. The Salmonella-containing solution is sucked into a precision pipet tip to which a viscous polymer solution is then added. Once the magnetophoretic chromatography process has been carried out for 10 min, the presence of 100 cfu/mL Salmonella bacteria can be detected with the naked eye because the bacteria have become concentrated at the narrow pipet tip. The performance of this method was evaluated by using dynamic light scattering and light absorption spectroscopy.