Electrochemical Biosensor for Rapid and Sensitive Detection of Magnetically Extracted Bacterial Pathogens

• Main Authors: Evangelyn C. Alocilja, Emma B. Setterington
• Format: Article
• Language: English
• Published: MDPI AG 2012-01-01
• Series: Biosensors
• Subjects: electrochemical biosensor; pathogen detection; magnetic polyaniline; screen-printed carbon electrode; cyclic voltammetry
• Online Access: http://www.mdpi.com/2079-6374/2/1/15

Biological defense and security applications demand rapid, sensitive detection of bacterial pathogens. This work presents a novel qualitative electrochemical detection technique which is applied to two representative bacterial pathogens, Bacillus cereus (as a surrogate for B. anthracis) and Escherichia coli O157:H7, resulting in detection limits of 40 CFU/mL and 6 CFU/mL, respectively, from pure culture. Cyclic voltammetry is combined with immunomagnetic separation in a rapid method requiring approximately 1 h for presumptive positive/negative results. An immunofunctionalized magnetic/polyaniline core/shell nano-particle (c/sNP) is employed to extract target cells from the sample solution and magnetically position them on a screen-printed carbon electrode (SPCE) sensor. The presence of target cells significantly inhibits current flow between the electrically active c/sNPs and SPCE. This method has the potential to be adapted for a wide variety of target organisms and sample matrices, and to become a fully portable system for routine monitoring or emergency detection of bacterial pathogens.