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Electrochemical biosensor for rapid and sensitive detection of magnetically extracted bacterial pathogens.

Setterington EB, Alocilja EC - Biosensors (Basel) (2012)

Bottom Line: Cyclic voltammetry is combined with immunomagnetic separation in a rapid method requiring approximately 1 h for presumptive positive/negative results.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA. ebs@msu.edu.

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.

No MeSH data available.


Related in: MedlinePlus

Cyclic voltammograms (a) and charge transfer values; (b) for electrochemical tests performed on pure B. cereus and E. coli O157:H7 cells, suspended at various concentrations in 0.1 M HCl solution, in the absence of c/sNPs.
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biosensors-02-00015-f004: Cyclic voltammograms (a) and charge transfer values; (b) for electrochemical tests performed on pure B. cereus and E. coli O157:H7 cells, suspended at various concentrations in 0.1 M HCl solution, in the absence of c/sNPs.

Mentions: From each electrochemical test, cyclic voltammograms (plot of response current vs. applied potential) were recorded. The third scan (of three consecutive scans performed) was chosen for analysis because it shows the most pronounced differences in current flow for different samples. Figure 4 depicts cyclic voltammograms and charge transfer values for pure (a) B. cereus and (b) E. coli O157:H7 cells suspended in 0.1 M HCl, in the absence of c/sNPs. The presence of cells has no effect on the electrochemical response, except at the highest concentrations tested, which are 106 and 107 CFU/mL. The increase in charge transfer observed at this high concentration can be explained by the conductivity of bacterial cell membranes and cytoplasm [19]. If the cells are packed densely enough, their membranes could form a conductive wire through which current is able to flow. Additionally, leakage of ions and cytoplasm out of the cells into the surrounding medium, which could be significant at high cell concentrations, increases the conductivity of the bulk solution and thereby increases current flow.


Electrochemical biosensor for rapid and sensitive detection of magnetically extracted bacterial pathogens.

Setterington EB, Alocilja EC - Biosensors (Basel) (2012)

Cyclic voltammograms (a) and charge transfer values; (b) for electrochemical tests performed on pure B. cereus and E. coli O157:H7 cells, suspended at various concentrations in 0.1 M HCl solution, in the absence of c/sNPs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263547&req=5

biosensors-02-00015-f004: Cyclic voltammograms (a) and charge transfer values; (b) for electrochemical tests performed on pure B. cereus and E. coli O157:H7 cells, suspended at various concentrations in 0.1 M HCl solution, in the absence of c/sNPs.
Mentions: From each electrochemical test, cyclic voltammograms (plot of response current vs. applied potential) were recorded. The third scan (of three consecutive scans performed) was chosen for analysis because it shows the most pronounced differences in current flow for different samples. Figure 4 depicts cyclic voltammograms and charge transfer values for pure (a) B. cereus and (b) E. coli O157:H7 cells suspended in 0.1 M HCl, in the absence of c/sNPs. The presence of cells has no effect on the electrochemical response, except at the highest concentrations tested, which are 106 and 107 CFU/mL. The increase in charge transfer observed at this high concentration can be explained by the conductivity of bacterial cell membranes and cytoplasm [19]. If the cells are packed densely enough, their membranes could form a conductive wire through which current is able to flow. Additionally, leakage of ions and cytoplasm out of the cells into the surrounding medium, which could be significant at high cell concentrations, increases the conductivity of the bulk solution and thereby increases current flow.

Bottom Line: Cyclic voltammetry is combined with immunomagnetic separation in a rapid method requiring approximately 1 h for presumptive positive/negative results.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA. ebs@msu.edu.

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.

No MeSH data available.


Related in: MedlinePlus