Colorimetric aptamer sensor based on nanogold-DNA and method for detecting oxytetracycline by using colorimetric aptamer sensor

An aptamer sensor, nano-gold technology, applied in the measurement of color/spectral properties, analysis by chemical reaction of materials, and material analysis by observing the impact on chemical indicators, which can solve the problem of expensive equipment and many interference factors. , instability and other problems, to achieve the effects of high recovery, high sensitivity and specificity, and simple and easy production methods

Pending Publication Date: 2020-02-07
CAPITAL NORMAL UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, there are mainly the following methods for the detection of antibiotic residues in eggs and other foods: fluorescence spectrophotometry has high sensitivity and strong specificity, but there are many interference factors and is unstable; thin-layer chromatography has the advantages of simple operation, short detection period, However, ideal separation effect cannot be achieved only with developing agent; liquid chromatography is a relatively classic separation and detection method with high separation efficiency, but the equipment used is expensive, and it is not easy to be widely used; enzyme-linked immunoassay is a relatively new detection method This method can be widely used in residue analysis, and has the advantages of rapidity, selectivity and high sensitivity; capillary electrophoresis analysis has been applied to the detection of tetracycline antibiotics, but it is mainly detected by optical analysis, so the sensitivity is limited. limitation

Method used

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  • Colorimetric aptamer sensor based on nanogold-DNA and method for detecting oxytetracycline by using colorimetric aptamer sensor
  • Colorimetric aptamer sensor based on nanogold-DNA and method for detecting oxytetracycline by using colorimetric aptamer sensor
  • Colorimetric aptamer sensor based on nanogold-DNA and method for detecting oxytetracycline by using colorimetric aptamer sensor

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Experimental program
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preparation example Construction

[0032] S1. Preparation of gold nanoparticles (AuNPs): AuNPs with a diameter of 13 nanometers (nm) can be prepared by reducing chloroauric acid with sodium citrate. The concentration of the chloroauric acid solution is 1 millimolar (mM), and the molar ratio of chloroauric acid and sodium citrate is 5:19.4. The concentration of nanogold solution prepared by this method is about 10 nanomole per liter (nM).

[0033] S2. Packing of DNA: Centrifuge the DNA in the form of aerosol in a centrifuge at a speed of 8000 revolutions per minute (rpm) for 5 minutes (min) to make it aggregate into a dry powder form; follow the instructions on the primer delivery list Add a certain amount of secondary filtered water to the indicated volume; divide the centrifuged primers with ultrapure water into several small tubes, and shake them well to facilitate subsequent experiments; take a certain volume of DNA stock solution in each tube, and put It is diluted 100 times, and its precise concentration ...

Embodiment 1

[0040] Example 1. Preparation of gold nanoparticles: Gold nanoparticles with a diameter of 13 nm can be prepared by reducing chloroauric acid with sodium citrate. The concentration of the chloroauric acid solution is 1 mM, and the molar ratio of chloroauric acid to sodium citrate is 5:19.4. The concentration of gold nanoparticles solution prepared by this method is about 10 nM.

[0041] The results showed that the prepared nano-gold solution was wine red, and its particle size and surface color were consistent with the literature reports. Taking ultrapure water as a blank, scan from wavelength 400 to 800 on the UV-visible spectrophotometer, and draw the absorption curve of nano gold, such as figure 1 As shown, the maximum absorption wavelength of gold nanoparticles appears at 520nm, which is the characteristic peak of plasmon absorption on the surface of spherical gold nanoparticles with a diameter of about 13nm. Calculated by Lambert-Beer's law, the concentration of the pre...

Embodiment 2

[0043] Embodiment 2. The colorimetric detection of oxytetracycline:

[0044] Take 100 μL of 40 mM urea solution in a centrifuge tube, add 400 μL of phosphoric acid (PB) (10 mM) solution, mix well, and incubate at room temperature for 30 min. Subsequently, 25 μL of OTC solutions of different concentrations were added, mixed well, and incubated under the same conditions for 15 min. Finally, add 10 μL of 1.25 M NaCl solution and dilute to 250 μL with ultrapure water. After the solution is stable for 5 minutes, transfer it to a quartz cuvette, measure the absorbance at 520nm and 620nm at room temperature using a UV spectrophotometer, and calculate A 620 / A 520 . Each sample was parallelized 6 times.

[0045] The results show that the detection principle of the colorimetric sensor based on AuNPs-OTC aptamer is as follows: image 3 shown. The dispersed gold nanometer solution is wine red, adding NaCl can reduce the repulsion between the unmodified negatively charged gold nanop...

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Abstract

The invention relates to a colorimetric aptamer sensor based on nanogold-DNA and a method for detecting oxytetracycline by using the colorimetric aptamer sensor, and belongs to the technical field ofenvironmental monitoring. The colorimetric aptamer sensor provided by the invention comprises nanogold and an OTC aptamer. The method for detecting oxytetracycline by applying the colorimetric aptamersensor comprises the following steps: 1, preparing the nanogold; 2, preparing the OTC aptamer; 3, mixing the nanogold and the OTC aptamer. The colorimetric sensor designed by the invention has the advantages of simplicity and convenience in operation, short detection time, high sensitivity, good selectivity, low detection limit, macroscopic property and the like, and is superior to other traditional OTC detection methods. The aptamer sensor disclosed by the invention can be successfully used for detecting oxytetracycline in an actual egg sample and detecting a recovery rate result of OTC in the egg sample, so the detection result is satisfactory; and a certain reference is provided for applying an aptamer-nanogold colorimetric method to detection of small molecules in foods.

Description

technical field [0001] The invention relates to a nano-gold-DNA-based colorimetric aptamer sensor and a method for detecting oxytetracycline using the sensor, in particular to a method for detecting oxytetracycline in eggs based on a nano-gold-DNA colorimetric aptamer sensor , belonging to the technical field of environmental monitoring. Background technique [0002] Animal food is one of the main foods that people rely on for survival. With the improvement of people's living standards, the consumption of animal food is increasing day by day. In the process of raising animals, in order to prevent and treat diseases, promote animal growth, and improve the utilization rate of nutrients in feed, antibiotics are widely used in compound feed, which has brought considerable economic benefits. However, the problem of their residues in animal foods has become increasingly prominent, and people's long-term consumption of such animal foods containing drug residues will pose a serious...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/78G01N21/33
CPCG01N21/33G01N21/78
Inventor 来晓霞闫尚刘桐刘月影相玉红
Owner CAPITAL NORMAL UNIVERSITY
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