A novel passive detection method for glucose sensing based on enzyme-catalyzed reaction regulating magnetic anisotropy

Researchers from various countries have focused on developing a passive glucose detection system to realize real-time monitoring of glucose content in the human body in the past decades. Here, we prepared Si/SiO₂/Ta/Co/Pt/GOx/Nafion magnetic anisotropy sensor to realize the passive detection of glucose. We have established the corresponding relationship between glucose concentration and the variation in magnetic properties of magnetization. Therefore, the passive detection of diagnosis was realized. The electrons produced by the enzyme-catalyzed reaction can linearly regulate magnetic heterostructures’ saturation magnetic field intensity. The magnetic anisotropy sensor shows a linear relationship in the range of 0 mM to 5 mM between the glucose concentration and the saturation magnetic field variation. The correlation coefficient is as high as R = 0.992. The sensitivity of the as-fabricated sensor is 132 emu·mM⁻¹·cm⁻³, with the limit of detection (LOD) about 698.1 µM. Also, the magnetic anisotropy sensor performs well in the test environment containing ascorbic acid, urea, NaCl, and KCl. Compared with the detection results of the commercial blood glucose meter, the relative errors (RES) of this method were within 10%, which indicates that the results given by the as-fabricated magnetic anisotropy sensor were in good agreement with the values given by the commercial glucose meter. This study proposes a novel passive detection method for glucose sensing, verifying that the electrons produced by the enzyme-catalyzed glucose reaction can regularly regulate the characteristic magnetic parameters of the spintronic device. The corresponding research ideas can be extended to detecting other enzyme-catalyzed reactions.