Spindle-like Fe3O4 nanoparticles for improving sensitivity and repeatability of giant magnetoresistance biosensors

Abstract

Magnetic labels are one of the most important components in giant magnetoresistance (GMR) biodetection systems and affect detection signals directly. Many researchers have improved the detection performance of GMR biosensors by optimizing the properties of their magnetic labels, including size, shape, coercivity, and magnetization. In most studies, magnetic labels are usually spherical, and there is little research involving alternative shapes. In this work, we prepared spindlelike Fe3O4 nanoparticles (NPs) by hydrothermal and heating reduction. The as-prepared magnetic NPs were incorporated in the GMR biodetection system. An ultralow limitation of detection concentration of 0.05 ng/ml was achieved, which can be attributed to the shape anisotropy of the spindlelike magnetic particles. A wide linear work range, 0.05–1000 ng/ml, can be achieved by the use of the spindlelike Fe3O4 NPs in GMR biodetection. Moreover, the NPs exhibit good repeatability after multiple measurements, which can be attributed to the NPs’ stable and effective magnetic diffusion field. The use of spindlelike Fe3O4 NPs as magnetic labels in this work provides a new method for improving the sensitivity and repeatability of GMR biodetection.

A New Platform of Iron Oxide-Based Nanoparticles Assay Using GMR Chip-Based Sensor With Microcontroller

“…7(a), decreasing the effective magnetic field reduces the number of magnetic moments parallel to the H B . As the MNPs are located on the surface of the GMR chip, the voltage is reduced [22] due to the MNPs' stray field that increases the resistivity of the GMR chip. A higher concentration of MNPs, which indicates the larger number of MNPs attached to the GMR chip surface, generates a larger net stray field [42] that causes a more voltage reduction [22].…”

“…To realize a simple system of GMR-based biosensors, previous works have employed the bare-die manufactured GMR chip for MNPs assay. Guan et al [22] reported the spindle-MNPs detection using bare-die GMR chip GF708 produced by Sensitec GmbH, Germany. With a similar chip, Zhang et al [23] quantified the Fe 3 O 4 MNPs concentration.…”

Evaluation of Metglas/polyvinylidene fluoride magnetoelectric bilayer composites for flexible in-plane resonant magnetic sensors

“…human body of about 10 -13 T to a strong magnetic field of over 1000 T [1][2][3][4][5]. Many kinds of magnetic field sensors based on various physical effects have been developed and applied, including fluxgate sensors [2,[5][6][7], Hall sensors, giant magnetoresistance (GMR) sensors [8][9][10][11][12], superconducting quantum interference devices [3,[13][14][15][16][17], optical pump atomic magnetometers [18][19][20][21] and so on. With the rise of wearable devices, as the core component of wearable device systems, flexible magnetic sensors have been widely studied [22][23][24][25][26].…”