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 Listeriaadhesion protein (LAP) during Listeria monocytogenes infection. This paper reports application of biotinylated Hsp60 as a capture molecule for living (viable) L. monocytogenesin a microf-luidic environment. Hsp60, immobilized on the surface of streptavidin-coated silicon dioxide exhibited specific capture of pathogenic Listeria against a background of other Listeriaspecies, Salmonella, Escherichia, Bacillus, Pseudomonas, Serratia, Hafnia, Enterobacter, Citro-bacter, and Lactobacillus. The capture efficiency of L. monocytogeneswas 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.