Arrayed amorphous wire sensing system for large-area magnetic beads detection

Amorphous wire sensors exhibit significant potential for magnetic bead-based biological detection applications due to their high sensitivity to magnetic fields. However, the flexibility and structural heterogeneity of amorphous microwires hinder their integration into MEMS processes, and their detection area restricts their effectiveness in biological detection applications. To overcome these limitations, we proposed a novel magnetic bead detection system based on the amorphous microwire GMI sensor. The sensor operates based on the off-diagonal magneto-impedance effect, detecting magnetic beads by measuring the voltage change in a pick-up coil. This system utilizes microfabricated grooves on glass substrates to enable precise alignment and fixation of the microwires. To expand the sensing area, an array configuration was adopted. The sensor exhibited a resolution of 0.75nT, a sensitivity of 5.997 V/Oe, and a linearity of 99.97 % within ±0.75 Oe range. Furthermore, by integrating microfluidic technology, we constructed a real-time detection system for monitoring magnetic bead solutions. This system can monitor magnetic bead solutions at concentrations ranging from 1 to 50 μg/ml over an area of 11 mm × 7 mm.