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Gold nanoparticle-labeled biosensor for rapid and sensitive detection of bacterial pathogens.

Wang Y, Alocilja EC - J Biol Eng (2015)

Bottom Line: By measuring the amount of AuNPs through an electrochemical method, the presence and the amount of the target bacteria were determined.Results showed a sensitivity of 10(1) colony forming units per milliliter (cfu/ml) with a linear range of 10(1)-10(6) cfu/ml.Compared to conventional culture plating methods, the biosensor reduced the detection time from 2 to 4 days to less than 1 hour with a simple target extraction method.

View Article: PubMed Central - PubMed

Affiliation: Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824 USA ; Present address: Division of Food Processing Science and Technology, U. S. Food and Drug Administration, Bedford Park, IL 60501 USA.

ABSTRACT

Background: Escherichia coli O157:H7 is one of the major foodborne bacterial pathogens and also a biodefense agent. To ensure food safety and public health, it is very important to develop rapid methods for E. coli O157:H7 detection. In this study, we designed a nanoparticle-labeled biosensor for the rapid detection of E. coli O157:H7 in broth.

Results: Magnetic nanoparticles (MNPs) were conjugated with monoclonal antibodies (Abs) to separate target E. coli O157:H7 cells from broth samples. Gold nanoparticles (AuNPs) were conjugated with polyclonal Abs, and were then introduced to the MNP-target complex to form a sandwich MNP-target-AuNP. By measuring the amount of AuNPs through an electrochemical method, the presence and the amount of the target bacteria were determined. Results showed a sensitivity of 10(1) colony forming units per milliliter (cfu/ml) with a linear range of 10(1)-10(6) cfu/ml.

Conclusions: Compared to conventional culture plating methods, the biosensor reduced the detection time from 2 to 4 days to less than 1 hour with a simple target extraction method. The AuNP-labeled biosensor has potential applications in the rapid detection of infectious agents for public health, biodefense, and food/water safety.

No MeSH data available.


Related in: MedlinePlus

Peak current vs. cell concentration of the gold nanoparticle (AuNP)-labeled biosensor for E. coli O157:H7 detection. The signal shows a linear relationship between 101 to 106 cfu/ml
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Fig6: Peak current vs. cell concentration of the gold nanoparticle (AuNP)-labeled biosensor for E. coli O157:H7 detection. The signal shows a linear relationship between 101 to 106 cfu/ml

Mentions: A linear relationship between signal to noise ratio (SNR) and cell concentration is shown in Fig. 6, with an R2 value of 0.953. The SNR was calculated as the peak current of AuNPs for each concentration divided by the current at 0.3 V of the blank, which was used as the signal of this biosensor. The SNR for 101, 102, 103, 104, 105 and 106 cfu/ml are 1.28, 1.56, 1.69, 1.73, 2.12 and 2.36, respectively. A statistical analysis using t test was conducted and the results are presented in Table 1. As shown, cell concentration at 101 cfu/ml has a P value of 0.0546 (which is close to critical value of P = 0.05). The P value for other concentrations shows that the samples are significantly different from the blank. Therefore, the lowest cell concentration is weakly 101 cfu/ml and strongly at 102 cfu/ml. These results verify that MNP-Ab-cell-Ab-AuNP is an effective approach to highly sensitive detection. The specificity of the biosensor, which largely depends on the monoclonal antibody used in magnetic separation, was evaluated in another study by our lab [21]. An inclusivity of 94 % and an exclusivity of 69 % was obtained [21]. The inclusivity was calculated as the number of positive tests identified by the antibody divided by the actual total positive test number. The exclusivity was calculated as the number of negative tests identified divided by the actual total negative test number. The specificity of the monoclonal and polyclonal Abs-based sandwich configuration was also verified in our previous study [8].Fig. 6


Gold nanoparticle-labeled biosensor for rapid and sensitive detection of bacterial pathogens.

Wang Y, Alocilja EC - J Biol Eng (2015)

Peak current vs. cell concentration of the gold nanoparticle (AuNP)-labeled biosensor for E. coli O157:H7 detection. The signal shows a linear relationship between 101 to 106 cfu/ml
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4591638&req=5

Fig6: Peak current vs. cell concentration of the gold nanoparticle (AuNP)-labeled biosensor for E. coli O157:H7 detection. The signal shows a linear relationship between 101 to 106 cfu/ml
Mentions: A linear relationship between signal to noise ratio (SNR) and cell concentration is shown in Fig. 6, with an R2 value of 0.953. The SNR was calculated as the peak current of AuNPs for each concentration divided by the current at 0.3 V of the blank, which was used as the signal of this biosensor. The SNR for 101, 102, 103, 104, 105 and 106 cfu/ml are 1.28, 1.56, 1.69, 1.73, 2.12 and 2.36, respectively. A statistical analysis using t test was conducted and the results are presented in Table 1. As shown, cell concentration at 101 cfu/ml has a P value of 0.0546 (which is close to critical value of P = 0.05). The P value for other concentrations shows that the samples are significantly different from the blank. Therefore, the lowest cell concentration is weakly 101 cfu/ml and strongly at 102 cfu/ml. These results verify that MNP-Ab-cell-Ab-AuNP is an effective approach to highly sensitive detection. The specificity of the biosensor, which largely depends on the monoclonal antibody used in magnetic separation, was evaluated in another study by our lab [21]. An inclusivity of 94 % and an exclusivity of 69 % was obtained [21]. The inclusivity was calculated as the number of positive tests identified by the antibody divided by the actual total positive test number. The exclusivity was calculated as the number of negative tests identified divided by the actual total negative test number. The specificity of the monoclonal and polyclonal Abs-based sandwich configuration was also verified in our previous study [8].Fig. 6

Bottom Line: By measuring the amount of AuNPs through an electrochemical method, the presence and the amount of the target bacteria were determined.Results showed a sensitivity of 10(1) colony forming units per milliliter (cfu/ml) with a linear range of 10(1)-10(6) cfu/ml.Compared to conventional culture plating methods, the biosensor reduced the detection time from 2 to 4 days to less than 1 hour with a simple target extraction method.

View Article: PubMed Central - PubMed

Affiliation: Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824 USA ; Present address: Division of Food Processing Science and Technology, U. S. Food and Drug Administration, Bedford Park, IL 60501 USA.

ABSTRACT

Background: Escherichia coli O157:H7 is one of the major foodborne bacterial pathogens and also a biodefense agent. To ensure food safety and public health, it is very important to develop rapid methods for E. coli O157:H7 detection. In this study, we designed a nanoparticle-labeled biosensor for the rapid detection of E. coli O157:H7 in broth.

Results: Magnetic nanoparticles (MNPs) were conjugated with monoclonal antibodies (Abs) to separate target E. coli O157:H7 cells from broth samples. Gold nanoparticles (AuNPs) were conjugated with polyclonal Abs, and were then introduced to the MNP-target complex to form a sandwich MNP-target-AuNP. By measuring the amount of AuNPs through an electrochemical method, the presence and the amount of the target bacteria were determined. Results showed a sensitivity of 10(1) colony forming units per milliliter (cfu/ml) with a linear range of 10(1)-10(6) cfu/ml.

Conclusions: Compared to conventional culture plating methods, the biosensor reduced the detection time from 2 to 4 days to less than 1 hour with a simple target extraction method. The AuNP-labeled biosensor has potential applications in the rapid detection of infectious agents for public health, biodefense, and food/water safety.

No MeSH data available.


Related in: MedlinePlus