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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

Immunomagnetic separation from sample matrix, magnetic alignment on SPCE surface, and electrochemical detection of B. cereus and E. coli O157:H7 cells.
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biosensors-02-00015-f002: Immunomagnetic separation from sample matrix, magnetic alignment on SPCE surface, and electrochemical detection of B. cereus and E. coli O157:H7 cells.

Mentions: The immuno-c/sNPs were used to isolate target cells from pure culture. Serial dilutions of B. cereus and E. coli O157:H7 cultures grown overnight in trypticase soy agar were prepared independently of one another in 0.1% (w/v) peptone water. Immuno-c/sNPs and an aliquot of the appropriate bacterial dilution (containing serially diluted cells and culture media) were combined in PBS buffer (for a final c/sNP concentration of 1 mg/mL), and hybridized for 30 min at room temperature with rotation. The immuno-c/sNP-cell complexes were magnetically separated and the supernatant removed. Complexes were washed twice with wash buffer (Tween-20 in PBS) and resuspended in PBS buffer. The immuno-c/sNP-cell solutions, and also pure bacterial dilutions, were plated to determine the number of viable cells present. Capture efficiency was calculated as the number of viable cells captured divided by the number of viable cells in the original dilution. The immunomagnetic separation procedure is depicted in Figure 2. Upon completion of immuno-functionalization of c/sNPs and immunomagnetic separation of target cells, the polyaniline shell of the c/sNPs visibly changed color from dark green to dark blue.


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

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

Immunomagnetic separation from sample matrix, magnetic alignment on SPCE surface, and electrochemical detection of B. cereus and E. coli O157:H7 cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-02-00015-f002: Immunomagnetic separation from sample matrix, magnetic alignment on SPCE surface, and electrochemical detection of B. cereus and E. coli O157:H7 cells.
Mentions: The immuno-c/sNPs were used to isolate target cells from pure culture. Serial dilutions of B. cereus and E. coli O157:H7 cultures grown overnight in trypticase soy agar were prepared independently of one another in 0.1% (w/v) peptone water. Immuno-c/sNPs and an aliquot of the appropriate bacterial dilution (containing serially diluted cells and culture media) were combined in PBS buffer (for a final c/sNP concentration of 1 mg/mL), and hybridized for 30 min at room temperature with rotation. The immuno-c/sNP-cell complexes were magnetically separated and the supernatant removed. Complexes were washed twice with wash buffer (Tween-20 in PBS) and resuspended in PBS buffer. The immuno-c/sNP-cell solutions, and also pure bacterial dilutions, were plated to determine the number of viable cells present. Capture efficiency was calculated as the number of viable cells captured divided by the number of viable cells in the original dilution. The immunomagnetic separation procedure is depicted in Figure 2. Upon completion of immuno-functionalization of c/sNPs and immunomagnetic separation of target cells, the polyaniline shell of the c/sNPs visibly changed color from dark green to dark blue.

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