Method for detecting bacteria amount of gold nanoparticles by using coated antibody

Abstract

The invention discloses a method for detecting bacterial amount of gold nanoparticles by using a coated antibody. The method provided by the invention comprises the following steps: I, the gold nanoparticles which are coated with a specific antibody of bacteria to be detected are reacted with a sample, and thus reaction liquid is obtained; and II, a dark-field scattering image can be obtained by using a dark-field microscope to observe the reaction liquid obtained in the step I, and the amount of the bacteria to be detected can be obtained by analyzing the dark-field scattering image with an image analysis technology. According to the method disclosed by the invention, The test shows that since the gold nanoparticles which are modified by the antibody are used as a probe to carry out a dark-field scattering imaging, and an automation image identification technology is adopted; and therefore the method has the advantages of high sensitivity, strong specificity, fast detection speed and capability of being suitable for quick and sensitive detection of bacillus coli.

Description

technical field [0001] The invention relates to the field of biotechnology, in particular to a method for detecting the number of bacteria with gold nanoparticles coated with antibodies. Background technique [0002] The detection of E. coli in food and water is of great significance for food hygiene. my country's current detection standard for Escherichia coli in food GB 4789.3-2010 adopts the count detection method based on differential culture, including two detection methods of coliform MPN count method and coliform plate count method. Both of these two detection methods require quite a long incubation time, such as 4 days for the MPN method and 3 days for the plate counting method, so they are not suitable for the rapid detection of food samples, especially fresh and live products. In terms of rapid detection methods, there are currently more immune methods such as ELISA, immunomagnetic bead enrichment, and immunochromatography, as well as a series of PCR-based detecti...

AI Technical Summary

Problems solved by technology

In terms of rapid detection methods, there are currently more immune methods such as ELISA, immunomagnetic bead enrichment, and immunochromatography, as well as a series of detection methods based on PCR (such as real-time PCR for rapid analysis, multiplex detection methods that focus on the simultaneous detection of multiple bacteria). PCR, reverse transcription PCR that can distinguish dead bacteria from live bacteria, and immune PCR for bacteria expressing specific toxins, etc.) can shorten the time required for the detection step, and the analysis and detection of the sample can be completed within several minutes to several hours, but Both of them are detection methods based on calibration curves, and the detection limit is still high due to the poor consistency of individual bacteria.

Therefore, when using the above method to detect actual samples, it is still necessary to carry out more complicated pretreatment and culture enrichment on the samples, and the total time required for the detection is still relatively long.

In addition, the reagents or instruments used in immunological methods such as ELISA and PCR series methods are expensive, and the detection cost is high, which is not suitable for large-scale promotion and use.

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