Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 3

TEM (a) and HRTEM (b) images of CdTe QDs.</p

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 7

(a) Fluorescence spectra of aptasensors with different concentrations (from a to h: 1010, 107, 105, 104, 103, 102, 10, 0 cfu•mL-1) of S. Typhimurium; (b) calibration curve of the fluorescence intensity of the QDs@ssDNA2 at 612 nm for S. Typhimurium detection.</p

Specificity result for the detection of <i>S</i>. <i>enteritidis</i>, <i>S</i>. <i>aureus</i>, <i>E</i>. <i>coli O157</i>:<i>H7</i>, <i>L</i>. <i>monocytogenes</i>, <i>B</i>. <i>cereus</i>, <i>P</i>. <i>aeruginosa</i> and <i>S</i>. <i>Typhimurium</i>.

Specificity result for the detection of S. enteritidis, S. aureus, E. coli O157:H7, L. monocytogenes, B. cereus, P. aeruginosa and S. Typhimurium.</p

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 6

(a) UV-visible absorption spectrum of 10 μL of 1 mg•mL-1 streptavidin-coated MNPs decorated with 50 μL of 10 nM aptamer. (b) Fluorescence spectra of different concentrations (from 70 μL to 10 μL) of ssDNA2@CdTe QDs of 30 μg·mL-1 ssDNA2@CdTe QDs. (c) Fluorescence spectra of aptamer&QDs-ssDNA2@MNPs after different incubation times with S. Typhimurium. (d) Fluorescence spectra of aptamer&QDs-ssDNA2@MNPs incubated with S. Typhimurium at different incubation temperatures.</p

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 1

The flow chart diagram of synthesis of QDs (a), QDs-ssDNA2 (b) and aptamer@MNPs (c).</p

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 2

Schematic diagram of (a) the synthesis of streptavidin magnetic nanoparticles and carboxyl CdTe QDs, (b) illustration of the detection of S. Typhimurium.</p

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 5

UV-vis absorption spectrum of MNPs@aptamer (curve a) and aptamer (curve b).</p

Comparison of different methods for the detection of <i>S</i>. <i>Typhimurium</i>.

Comparison of different methods for the detection of S. Typhimurium.</p

Aptamer-based fluorometric determination of <i>Salmonella Typhimurium</i> using Fe₃O₄ magnetic separation and CdTe quantum dots - Fig 4

(a) Fluorescence spectra of QDs (curve a) and QDs@ssDNA2 (curve b); (b) UV-vis absorption spectrum of QDs and QDs@ssDNA2.</p

Determination of <i>S</i>. <i>Typhimurium</i> in real samples.

Determination of S. Typhimurium in real samples.</p