title: Electrochemical biosensor for rapid and sensitive detection of magnetically extracted bacterial pathogens.
abstract: 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.
authors.affiliation: Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA. ebs@msu.edu.
authors.forename: Emma B
authors.initials: EB
authors.lastname: Setterington
authors.affiliation: Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA. alocilja@msu.edu.
authors.forename: Evangelyn C
authors.initials: EC
authors.lastname: Alocilja