Effect of the Size of Immunomagnetic Beads on Capture Efficiency for Foodborne Pathogenic Bacteria

Abstract:

Particle size is a critical factor for capture efficiency (CE) of immunomagnetic beads (IMBs). IMBs were prepared by conjugating micrometer size (1 μm) or submicrometer size (300 nm)of superparamagnetic beads with anti- Salmonella polyclonal antibody. The amount of coupled antibody and the recovery rate were measured by flow cytometer and spectrophotometer, respectively. The results showed that compared with micron-IMBs, submicron-IMBs had a higher amount of coupled antibody and a higher recovery rate in buffer, and the CE was higher (300 nm: 55%, 1 μm: 41%). However, submicron-IMBs had a lower recovery rate in milk, which led to asignificant reduction of the CE of submicron-IMBs(300 nm: 15%, 1 μm: 26%). Therefore, the particle size of IMBs should be determined according to the volume and viscosity of samples.