Micro-fluidic magnetic bead detection method and device based on giant magneto-resistance

Abstract

The invention discloses a micro-fluidic magnetic bead detection method and a micro-fluidic magnetic bead detection device based on giant magneto-resistance. The method comprises the steps of feeding an immune-magnetic bead solution in an immune-magnetic bead solution inlet, feeding a cell solution by a cell solution inlet, mixing the two solutions in a mixing chamber to form a mixed solution and then entering an inverted tri-prism micro-tube, magnetizing immune-magnetic beads by a magnetic field generated by a permanent magnet, and slowly flowing the immune-magnetic beads along the tube wall of the tri-prism micro-tube; the resistance value of a giant magneto-resistance chip is changed due to the influence on a horizontal magnetic field obtained by immune-magnetic bead magnetization, a level signal of a connecting point of a Wheatstone bridge is output a signal processing module by the giant magneto-resistance chip, and a signal processing module is used for judging the distance between the immune-magnetic bead distance and the center of a giant magneto-resistance resistor stripe according to the resistance value of the giant magneto-resistance calculated according to an input level. The method provided by the invention is applicable to detecting the positions of microcosmic substances, and being capable of precisely detecting the position change of the immune-magnetic beads.

Description

technical field [0001] The invention relates to the application field of microfluidics, in particular to a method and a device for detecting the position of magnetic beads by using a giant magnetoresistance sensor. Background technique [0002] Immunomagnetic beads are a new immunological technology developed in recent years. It combines the unique advantages of solidified reagents with highly specific immunological reactions. Based on immunology, it penetrates into pathology, physiology, pharmacology, and microorganisms. It has been widely used in immunoassay, cell separation, purification of biological macromolecules and molecular biology. [0003] At present, the research on the quantitative detection of immunomagnetic beads is relatively extensive and in-depth, but there is almost no research on the localization of immunomagnetic beads. Some existing magnetic substance positioning methods and devices are almost all for macroscopic substances. For example, in the patent ...

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Problems solved by technology

[0003] At present, the research on the quantitative detection of immunomagnetic beads is relatively extensive and in-depth, but there is almost no research on the localization of immunomagnetic beads.

Some existing magnetic substance positioning methods and devices are almost all for macroscopic substances. For example, in the patent literature with the Chinese patent application number 201210224965.X and the name "a remote positioning method and system for objects containing permanent magnets" Provided is a remote positioning method and system based on no less than four magnetic field sensor array planes, the target area is located between four or more magnetic field sensor array planes, the point with the strongest field of each plane is found, and then the three-dimensional geometry is used Knowledge combined with the information of magnetic field compensation can locate the remote target. The sensor array includes four or more non-fixed magnetic field sensor array planes, a Hall sensor, and a magnetoresistive sensor; but the method and system have the following disadvantages: first , the structure of the sensor array is relatively complex, which increases the difficulty of the manufacturing process; second, the resolution of the sensor used is relatively large, and it is difficult to detect small changes, so it is not suitable for the positioning of microscopic substances. If the system is used to locate some microscopic magnetic materials , the error is larger

However, this article simply studies the effect of the position change of the magnetic beads on the giant magnetoresistance value under the condition of a one-dimensional fixed linear trajectory, and does not describe how to specifically detect the spatial position of the microfluidic magnetic beads.

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