Design of Biological Weak Magnetic Field Detection System Based on TMR Sensor

Biological weak magnetic field detection has gradually become a research hotspot.The miniaturized and high performance magnetic sensor detection system has important application prospects in biomolecular detection, magnetic anomaly detection, aerospace and other fields. Traditional biomolecular detection methods are expensive, time-consuming and low accuracy, and are gradually replaced by new magnetic sensor detection methods. In this study, a biodetection system based on the tunnel magnetoresistive effect sensor is proposed to detect magnetosomes in the following magnetotactic bacteria. The biological detection system is composed of the TMR and the differential amplifier, which is of great significance for the early detection of human cancer in the future. In this paper, a biological detection system is first used to simulate the detection of weak biological magnetic field in energized solenoid. The measurement range of the biological weak magnetic field detection system is ± 30 Oe, and the magnetic induction intensity change of 10nT can be accurately identified. The linear regression equation Y = 0.90926 + 0.00113X (R = 0.99983, P < 0.0001, N = 10) was obtained by amplifying the TMR output signal through a differential amplifier. At the same time, the average number of magnetosomes in magnetotactic bacteria is 22.8, which can satisfy the accurate detection of 103 units of magnetotactic bacteria. By measuring magnetotactic bacteria with different gradient concentrations, the regression equation between magnetotactic bacteria concentration and output voltage is Y = 0.90926 + 0.06732X (R = 0.99838, P < 0.0001, N = 6). This method can detect the biological weak magnetic field quickly and accurately with good recovery and reproducibility.