Abstract:

The influence of antibody-coupling methods such as direct binding and streptavidin-biotin system on the
capture efficiency of immunomagnetic beads of different sizes (180, 350 nm and 1150 nm) for Listeria monocytogenes was
compared. The results showed that the capture efficiency of immunomagnetic beads using streptavidin-biotin method was
approximately two-fold higher than that of direct binding method. Meanwhile, the size of magnetic beads had significantly
effect on the capture efficiency. When the dosage of immunomagnetic beads was 100 μg, the capture efficiencies of
beads 180, 350 nm and 1150 nm in diameter were 95%, 18% and 9%, respectively, during the separation of Listeria
monocytogenes. Therefore, the 180-nm-diameter immunomagnetic beads prepared with streptavidin-biotin system can
provide a low-cost, easy-to- use and efficient method for rapid enrichment and detection of Listeria monocytogenes.

Key words: Listeria monocytogenes, immunomagnetic separation, streptavidin