A photoelectrochemical detection method for ochratoxin a based on double signal amplification

A kind of ochratoxin and photoelectrochemical technology, which is applied in the direction of measuring devices, scientific instruments, and material analysis through electromagnetic means, can solve the problems that the stability needs to be further improved, so as to hinder electron transfer, weaken the signal, and improve the recognition ability and the effect of sensitivity

CN108760852BActive Publication Date: 2021-03-23JIANGXI NORMAL UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2021-03-23

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Abstract

A photoelectrochemical ochratoxin A detection method based on double signal amplification is provided. A graphene oxide / cadmium sulfide / molybdenum disulfide / nanogold composite is adopted as a photoelectric active material. An accessory DNA and an ochratoxin A aptamer modify an electrode through hybridization in order to form a biological sensing interface, porphyrin is embedded into a DNA double-strand structure, a substrate photoelectric material is sensitized and strong photocurrent signals are generated. Ochratoxin A that is a detection target is combined with the aptamer, and therefore, aporphyrin photosensitizer on the surface of the electrode falls off on the one hand to significantly weaken the photocurrent signals, on the other hand, the DNA labeled with silica nanoparticles is bound to the surface of the electrode to further weaken the signals due to steric hindrance effects, and the change of photocurrent and the concentration of the target have a linear relationship in a certain range. The method is suitable for specific identification of the aptamer and the target, and a double signal amplification mechanism is adopted, so that high-sensitivity high-selectivity detection of the concentration of the target can be achieved.
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Description

technical field

[0001] The invention relates to a photoelectrochemical ochratoxin A detection method based on double signal amplification, including the construction of a photoelectrochemical biosensor of graphene oxide / cadmium sulfide / molybdenum disulfide / nano-gold composite, belonging to the field of photoelectrochemical bioanalysis. Background technique

[0002] Ochratoxin is a secondary metabolite produced by certain species of Aspergillus and Penicillium, which has a wide range of pollution and can contaminate almost all kinds of food commodities (such as wheat, corn, barley, rye, beans, potatoes, bread, dried fruit, nuts, wine). Ochratoxins are mainly composed of ochratoxins A, B, and C, among which ochratoxin A (OTA) is the most toxic, widely distributed, and most closely related to human health. Due to the toxic, teratogenic, carcinogenic, mutagenic and immunosuppressive effects of OTA on animals and humans, rapid and sensitive detection of OTA is of great hygienic ...

Examples

Embodiment 1

[0027] (1) 0.006mol Na 2 MoO 4 and an equivalent amount of CdSO 4 Added to 30mL concentration is 0.1mg mL -1In the aqueous dispersion of graphene oxide, subsequently, 0.25mol thiourea was added to the above solution and stirred for 2 hours to form a milky white suspension; the suspension was transferred to a 50mL reactor and reacted for 18 hours at 200 degrees Celsius; the resulting solid product Centrifuge and wash several times, and then redisperse into 10mL aqueous solution.

[0028] (2) Nano-gold modified graphene oxide supported cadmium sulfide molybdenum sulfide nanocomposite (GO-CdS-MoS 2 -Au): 48.6 μL sodium citrate (100 mM), 10 μL Tween 80 (100 mM) and 10 μL HAuCl 4 ·3H 2 O (48.5mM) was quickly added to the GO-CdS-MoS prepared in step (1) 2 In the dispersion liquid, microwave heating to 60° C. for 5 minutes to react, and the obtained product was alternately washed three times with ethanol and water.

[0029] (3) Add 1.8mL n-hexanol, 7.5mL cyclohexane and 1.77mL...