Targeted capture of pathogenic bacteria using a mammalian cell receptor coupled with dielectrophoresis on a biochip.

Efficient capture of target analyte on biosensor platforms is a prerequisite for reliable and specific detection of pathogenic microorganisms in a microfluidic chip. Antibodies have been widely used as ligands; however, because of their occasional unsatisfactory performance, a search for alternative receptors is underway. Heat shock protein 60 (Hsp60), a eukaryotic mitochondrial chaperon protein is a receptor for Listeria adhesion protein (LAP) during Listeria monocytogenes infection. This paper reports application of biotinylated Hsp60 as a capture molecule for living (viable) L. monocytogenes in a microfluidic environment. Hsp60, immobilized on the surface of streptavidin-coated silicon dioxide exhibited specific capture of pathogenic Listeria against a background of other Listeria species, Salmonella, Escherichia, Bacillus, Pseudomonas, Serratia, Hafnia, Enterobacter, Citrobacter, and Lactobacillus. The capture efficiency of L. monocytogenes was 83 times greater than another Listeria receptor, the monoclonal antibody, mAb-C11E9. Additionally, the capture rate was further increased on a Hsp60-coated biochip by 60% when a dielectrophoresis force was applied for 5 min at the beginning of the final 1 h incubation step. Our data show that Hsp60 could be used for specific detection of L. monocytogenes on a biochip sensor platform.