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Electrochemical Immunoassay of Escherichia coli O157:H7 Using Ag@SiO2 Nanoparticles as Labels.

Chen GZ, Yin ZZ, Lou JF - J Anal Methods Chem (2014)

Bottom Line: Silica coated silver (Ag@SiO2) nanoparticles were prepared and characterized by transmission electron microscope (TEM) and UV-vis absorption, and the nanoparticles were used as labels in sandwich-type immunosensor of Escherichia coli O157:H7 (E. coli O157:H7).Then, the number of E. coli O157:H7 could be indirectly reflected by the signal intensity of labeled Ag(+).And the results showed that the DPV signals were proportional to the logarithm of the E. coli O157:H7 concentration in the range from 20 cfu/mL to 8.0 × 10(3) cfu/mL with the detection limit of 13 cfu/mL.

View Article: PubMed Central - PubMed

Affiliation: College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, China.

ABSTRACT
Silica coated silver (Ag@SiO2) nanoparticles were prepared and characterized by transmission electron microscope (TEM) and UV-vis absorption, and the nanoparticles were used as labels in sandwich-type immunosensor of Escherichia coli O157:H7 (E. coli O157:H7). The labels involved in immunoreaction were dissolved by mixed acid of hydrofluoric acid and nitric acid, and the released Ag(+) ions were electrochemical stripping analyzed (via differential pulse voltammetry, DPV) at poly(acrylic acid)/poly(diallyldimethylammonium chloride)/carbon nanotubes (PAA/PDCNT) modified glass carbon electrode (GCE), which obviously enhanced the signal of Ag(+) stripping. Then, the number of E. coli O157:H7 could be indirectly reflected by the signal intensity of labeled Ag(+). And the results showed that the DPV signals were proportional to the logarithm of the E. coli O157:H7 concentration in the range from 20 cfu/mL to 8.0 × 10(3) cfu/mL with the detection limit of 13 cfu/mL.

No MeSH data available.


Related in: MedlinePlus

Effects of (a) incubation temperature and (b) incubation time on the stripping current response of Ag+ from immunoreaction labels. The concentration of E. coli O157:H7 was 500 cfu/mL.
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fig2: Effects of (a) incubation temperature and (b) incubation time on the stripping current response of Ag+ from immunoreaction labels. The concentration of E. coli O157:H7 was 500 cfu/mL.

Mentions: Incubation temperature and incubation time were important factors for the immunological reaction. The effect of incubation temperature was studied in the range of 25 to 50°C via the stripping current of Ag+ from immunoreaction labels (Figure 2(a)). It was found that the maximum signal occurred at an incubation temperature of 37°C. When the temperature was higher than 37°C, the peak current reduced, which might be attributed to the decrease of the biomolecule activity at high temperature [19]. Therefore, 37°C was selected as incubation temperature.


Electrochemical Immunoassay of Escherichia coli O157:H7 Using Ag@SiO2 Nanoparticles as Labels.

Chen GZ, Yin ZZ, Lou JF - J Anal Methods Chem (2014)

Effects of (a) incubation temperature and (b) incubation time on the stripping current response of Ag+ from immunoreaction labels. The concentration of E. coli O157:H7 was 500 cfu/mL.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4020444&req=5

fig2: Effects of (a) incubation temperature and (b) incubation time on the stripping current response of Ag+ from immunoreaction labels. The concentration of E. coli O157:H7 was 500 cfu/mL.
Mentions: Incubation temperature and incubation time were important factors for the immunological reaction. The effect of incubation temperature was studied in the range of 25 to 50°C via the stripping current of Ag+ from immunoreaction labels (Figure 2(a)). It was found that the maximum signal occurred at an incubation temperature of 37°C. When the temperature was higher than 37°C, the peak current reduced, which might be attributed to the decrease of the biomolecule activity at high temperature [19]. Therefore, 37°C was selected as incubation temperature.

Bottom Line: Silica coated silver (Ag@SiO2) nanoparticles were prepared and characterized by transmission electron microscope (TEM) and UV-vis absorption, and the nanoparticles were used as labels in sandwich-type immunosensor of Escherichia coli O157:H7 (E. coli O157:H7).Then, the number of E. coli O157:H7 could be indirectly reflected by the signal intensity of labeled Ag(+).And the results showed that the DPV signals were proportional to the logarithm of the E. coli O157:H7 concentration in the range from 20 cfu/mL to 8.0 × 10(3) cfu/mL with the detection limit of 13 cfu/mL.

View Article: PubMed Central - PubMed

Affiliation: College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, China.

ABSTRACT
Silica coated silver (Ag@SiO2) nanoparticles were prepared and characterized by transmission electron microscope (TEM) and UV-vis absorption, and the nanoparticles were used as labels in sandwich-type immunosensor of Escherichia coli O157:H7 (E. coli O157:H7). The labels involved in immunoreaction were dissolved by mixed acid of hydrofluoric acid and nitric acid, and the released Ag(+) ions were electrochemical stripping analyzed (via differential pulse voltammetry, DPV) at poly(acrylic acid)/poly(diallyldimethylammonium chloride)/carbon nanotubes (PAA/PDCNT) modified glass carbon electrode (GCE), which obviously enhanced the signal of Ag(+) stripping. Then, the number of E. coli O157:H7 could be indirectly reflected by the signal intensity of labeled Ag(+). And the results showed that the DPV signals were proportional to the logarithm of the E. coli O157:H7 concentration in the range from 20 cfu/mL to 8.0 × 10(3) cfu/mL with the detection limit of 13 cfu/mL.

No MeSH data available.


Related in: MedlinePlus