Phagomagnetic separation and electrochemical magneto-genosensing of pathogenic bacteria.

This paper addresses the use of bacteriophages immobilized on magnetic particles for the biorecognition of the pathogenic bacteria, followed by electrochemical magneto-genosensing of the bacteria. The P22 bacteriophage specific to Salmonella (serotypes A, B, and D1) is used as a model. The bacteria are captured and preconcentrated by the bacteriophage-modified magnetic particles through the host interaction with high specificity and efficiency. DNA amplification of the captured bacteria is then performed by double-tagging polymerase chain reaction (PCR). Further detection of the double-tagged amplicon is achieved by electrochemical magneto-genosensing. The strategy is able to detect in 4 h as low as 3 CFU mL(-1) of Salmonella in Luria-Bertani (LB) media. This approach is compared with conventional culture methods and PCR-based assay, as well as with immunological screening assays for bacteria detection, highlighting the outstanding stability and cost-efficient and animal-free production of bacteriophages as biorecognition element in biosensing devices.