CN104634968A - Biosensor system for pathogenic bacterium detection - Google Patents

Abstract

The invention relates to a biosensor system for detecting pathogenic bacteria, comprising two parts: the first part consists of a magnetostrictive material with antibodies bound on its surface, a Helmholtz coil (a Helmholtz coil) and a closed speaker A biosensor platform composed of devices. The second part is an information analysis system composed of DC power supply, wires, coils and lock-in amplifiers or network analyzer (AV3620) or impedance analyzer (Agilent 4294A). The detection limit of the biosensor of the present invention is 100cfu/mL, and the detection time varies with the viscosity of the detection solution, generally within 20-60min. Therefore, the biosensor of the present invention has the advantages of short detection time and low detection limit, can detect pathogenic bacteria in liquid or solid samples simply, quickly and accurately, and is also suitable for portable applications.

Description

Biosensor system for detection of pathogenic bacteria

technical field

The invention relates to the technical field of detection, in particular to a biosensor system for detection of pathogenic bacteria.

Background technique

Various analytical procedures are known in the art for detecting target species in test samples. For example, using the specific response mechanism of the immune system, the presence or amount of antigens can be determined by staining or molecular labeling of antibodies. The present invention also uses the specific reaction mechanism of the immune system to bind the antibody on the surface of the magnetostrictive material through molecular modification. When the antigen is combined with the antibody, the frequency of the material changes, and the antigen's frequency is determined through information system analysis. presence or quantity.

Recently, magnetostrictive material biosensing is known, and magnetostrictive material is used as a functional material for energy and information conversion, that is, it is used as a sensitive element for sensor information conversion. The biosensor of the present invention uses the magnetostrictive material as the platform of the biosensor.

The magnetostrictive material of the recently known magnetostrictive material biosensor is molecularly modified, and its active group is a mercapto group, which is generally used on electrodes for electrochemical reactions.

Magnetic labels have recently been used in microfluidic assays to detect the presence or amount of analytes. The use of magnetic labels as, for example, magnetic particles, also called magnetic beads, can be actuated by applying a magnetic field and thus speed up the analysis process. Magnetic beads are identified using an optical detection system.

It is known recently that the bacterium solution to be tested is added to the colloidal gold particle solution containing the aptamer of the target microorganism and the aptamer complementary chain to incubate, and the aptamer complementary chain is connected on the surface of the colloidal gold particle I, and the target microorganism and the aptamer complementary chain are connected to each other. The recognition and binding of the aptamer is a change in the aggregation and dispersion state of the colloidal gold particles, resulting in a change in the color of the solution to judge the detection result.

Recently, it is known that a biosensitive sensor is used to capture the sample detection solution, and a blank control and a standard positive concentration control are set at the same time to start the adenosine triphosphate synthesis reaction, and then a fluorescent scanner is used for detection.

Contents of the invention

The object of the present invention is to provide a biosensor system capable of detecting pathogenic bacteria in liquid or solid samples. In order to realize the purpose of the present invention, it is planned to adopt the following technical solutions:

One aspect of the present invention relates to a magnetostrictive material biosensor system for detecting bacteria, comprising:

Magnetostrictive materials and surface-bound antibodies;

Working coil, Helmholtz coil, power connection line, and DC power supply;

An information analysis system, the information analysis system includes a network analysis system and an impedance analysis system. There are 3 methods for information analysis: lock-in amplifier method, network analyzer (AV3620) method and impedance analyzer (Agilent 4294A) method. A preferred embodiment is the network analyzer method.

In a preferred embodiment of the present invention, it is characterized in that the material used for the working coil is an alloy material capable of causing resonance with the magnetostrictive material. The magnetostrictive material described in the present invention is a class of material whose length, width and height all change under the action of a magnetic field. In this embodiment, the magnetostrictive material used is usually magnetostrictive microparticles (MSP) or Magnetostrictive microcantilever (MSMC), generally its optimal length is the diameter of the coil wire.

In a preferred embodiment of the present invention, it is characterized in that the surface of the magnetostrictive material is coated with a SiO ₂ shell, and then the amino group is derivatized on the molecular surface, and then the amino group is hydroxylated to bind the antibody through the hydroxyl group.

Another aspect of the present invention also relates to a method for detecting pathogenic bacteria in a sample using the above-mentioned magnetostrictive material biosensor system for detecting bacteria, which is characterized in that it includes the following steps:

Place the magnetostrictive material bound with antibody in the working coil, let the sample slowly flow through the magnetic strip through the pipeline, so that the bacteria in the sample can bind to its antibody;

Detect the change of the resonant frequency produced by the magnetic strip and the coil, and after processing by the information system, the number of germs can be determined.

In a preferred embodiment of the present invention, it is characterized in that described method is used for following detection:

- Used for the detection of pathogenic bacteria in liquid foods such as beverages, milk, and oils,

-For the detection of pathogenic bacteria on the surface of fresh fruits and vegetables.

- For the detection of bacteria in drinking water.

-For the detection of pathogenic bacteria in human urine samples.

-Pathogen diagnostic tool for food and environmental diagnosis.

The information analysis system of the biosensor of the present invention includes a network analysis system and an impedance analysis system, etc. Usually, the network analysis system uses a vector network analyzer for frequency sweep detection, and can also build a simple circuit, using chips such as amplitude and phase measurement to detect magnetic Amplitude change in a stretchable material. Because the network analysis system is relatively large and expensive, it is necessary to simplify the program in portable applications.

The detection limit of the biosensor of the present invention is 100cfu/mL, and the detection time varies with the viscosity of the detection solution, generally within 20-60min. The biosensor system disclosed in the invention can detect bacteria on liquid or solid surfaces, and the method is simple, fast and accurate, and is also suitable for portable applications.

Description of drawings

Fig. 1 is the illustration of the liquid sample detected by the magnetostrictive material biosensor of the present invention;

Figure 2 is a schematic diagram of the connection relationship between the coil and the magnetic strip, and the specifications of the magnetic strip vary depending on the object to be detected.

Detailed ways

Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

An embodiment of using the biosensor system of the present invention to detect an aqueous solution containing Listeria:

Step 1. Magnetostrictive material binding antibody

The magnetostrictive material is coated with a SiO2 shell, and then the amino group is derivatized on the molecular surface, and then the amino group is hydroxylated, and the antibody is bound after adding a catalyst.

Step 2. Combination of antibody and antigen

The magnetic strip bound with the antibody is placed in the coil, and the aqueous solution is slowly flowed through the magnetic strip through the pipeline (composed of a leather tube and a glass tube), so that the Listeria in the aqueous solution can bind to its antibody.

Step 3. Detection

The number of Listeria can be determined through the change of the resonant frequency generated by the magnetic strip and the coil and processed by the information system.

Step 4. The test results are as follows:

Dynamic frequency of biosensor detection of Listeria

It is not difficult to see from the above results that the frequency of the test results of this sample decreases with the increase of the bacterial concentration, and the frequency basically remains stable when the concentration reaches a high level.

Utilize the embodiment of biosensor system of the present invention to the detection of pathogenic bacteria on apple surface:

Step 1. Immunospecific reaction on apple surface

First put the apple in the detection container, then sprinkle 55 magnetic strips bound with antibodies (50 for detection and 5 for control) on the surface of the apple, wait for 1min, let the antibody bound on the magnetic strip Antibodies bind to Salmonella.

Step 2. Test results

The wireless detector detects 55 magnetic stripes for 1 min each.

Step 3. Data processing and result judgment

If the resonance frequency of the detection sensor is the same as that of the control, it is considered that there is no Salmonella on the apple, and if the detection peak value is lower than that of the control, it is determined that there is Salmonella infection in the apple.

Step 4, reclaim the magnet on the surface of the apple with an electromagnet.

The test results are as follows:

The test sensor had the same resonant frequency as the control, and it was determined that the apples were free of Salmonella infection.

The above description is a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (5)

1. A magnetostrictive material biosensor system for detecting bacteria, comprising: Magnetostrictive microparticles and surface-bound antibodies; Working coil, Helmholtz coil, power connection line, and DC power supply; Information analysis system, including lock-in amplifier, network analyzer (AV3620) or impedance analyzer (Agilent 4294A) in the described information analysis system; Preferably, described information analysis system is network analysis system. 2. The magnetostrictive material biosensor system according to claim 1, characterized in that the material used for the working coil is an alloy material capable of resonating with the magnetostrictive material. 3. The magnetostrictive material biosensor system according to claim 1, characterized in that the surface of the magnetostrictive material is coated with SiO ₂ shells, then derivatized amino groups on its molecular surface, and then amino groups are hydroxylated, and then the amino groups are hydroxylated. Binding antibody. 4. The method for detecting pathogenic bacteria in a sample using the above-mentioned magnetostrictive material biosensor system for detecting bacteria is characterized in that it comprises the following steps: Place the magnetostrictive material bound with antibody in the working coil, let the sample slowly flow through the magnetic strip through the pipeline, so that the bacteria in the sample can bind to its antibody; Detect the change of the resonant frequency produced by the magnetic strip and the coil, and after processing by the information system, the number of germs can be determined. 5. The method according to claim 4, characterized in that said method is used for the following detections: - Used for the detection of pathogenic bacteria in beverages, milk, and oily liquid foods; -For the detection of pathogenic bacteria on the surface of fresh fruits and vegetables; - for the detection of bacteria in drinking water; - For the detection of pathogenic bacteria in human urine samples; -Pathogen diagnostic tool for food and environmental diagnosis.