System and method for gene detection

A system for gene detection comprising:

• a sensor module comprising a plurality of magnetic sensors in an arrangement of a matrix;
• and
• a signal processing chip;
• wherein:
• the plurality of magnetic sensors are chemically pretreated and combined with a biological probe;
• the combined magnetic sensors and biological probe are disposed in a DC magnetic field and an AC magnetic field, and in sufficient contact with combined magnetic particles and DNA molecules to be detected, so that the DNA molecules to be detected are matched and hybridized with the biological probe;
• the plurality of magnetic sensors are then cleaned so that the DNA molecules to be detected that are not hybridized are removed;
• the magnetic particles combined with the DNA molecules to be detected that are hybridized are relatively fixed above the magnetic sensors so that a scattered magnetic field is formed and the reluctivity of the magnetic sensors varies under the scattered magnetic field;
• the sensor module is formed on the signal processing chip through sputtering;
• the signal processing chip comprises a front-end circuit configured to transform variation of the reluctivity of the magnetic sensors into a first electrical signal and a signal processing circuit configured to process the first electrical signal and output a second electrical signal representing a detection result of a DNA molecule to be detected;
• the front-end circuit comprises a row address selector and a column address selector coordinated with each other and configured to allow the current to flow into selected magnetic sensors, and a biasing circuit and a pre-amplifier;
• the biasing circuit comprises a plurality of diodes individually corresponding to the plurality of magnetic sensors;
• each diode is connected in series with a corresponding magnetic sensor so as to prevent the current from flowing into unselected magnetic sensors;
• the pre-amplifier comprises a differential amplifier, a first clipper stabilizing circuit, a second clipper stabilizing circuit, a third clipper stabilizing circuit, a first resistor and a second resistor;
• the differential amplifier comprises a positive input port, a negative input port, a first positive output port, a first negative output port, a second positive output port and a second negative output port;
• the first clipper stabilizing circuit is connected with the first positive output port and the first negative output port;
• the second clipper stabilizing circuit is connected with the second positive output port and the second negative output port;
• the third clipper stabilizing circuit is connected with the positive input port and the negative input port;
• the positive input port is connected with the first negative output port through the first resistor;
• the negative input port is connected with the second negative output port through the second resistor;
• the input signal of the differential amplifier is an electrical signal output from the plurality of magnetic sensors and representing variation of the reluctivity of the magnetic sensors, and input through the positive input port and the negative input port;
• and
• the output signals of the differential amplifier comprise a first output signal output from the first positive output port and a second output signal output from the second positive output port.

A method for gene detection comprising:

• step 1:
• magnetizing a plurality of magnetic particles with a DC magnetic field and an AC magnetic field;
• step 2:
• combining a plurality of magnetized magnetic particles and a plurality of DNA molecules to be detected;
• step 3:
• chemically pretreating magnetic sensors and combining the magnetic sensors with a biological probe;
• step 4:
• establishing the DC magnetic field and the AC magnetic field around the combined magnetic sensors and biological probe as described in step 3 and establishing a signal baseline;
• step 5:
• disposing the combined DNA molecules to be detected and magnetic particles as described in step 2 on the combined magnetic sensors and biological probe as described in step 3 so that the combined DNA molecules to be detected and magnetic particles are in sufficient contact with the combined magnetic sensors and biological probe;
• step 6:
• cleaning the plurality of magnetic sensors, removing the DNA molecules to be detected that are not hybridized, and then relatively fixing the magnetic particles combined with the hybridized DNA molecules to be detected above the magnetic sensors so that a scattered magnetic field can be formed;
• step 7:
• transforming variation of the reluctivity of the plurality of magnetic sensors into a first electrical signal through a signal processing chip, the reluctivity of the plurality of magnetic sensors varying under the scattered magnetic field;
• and
• step 8:
• processing the first electrical signal and outputting a second electrical signal representing a detection result of the DNA molecules to be detected with the signal processing chip.