A giant magnetoimpedance sensor for sensitive detection of streptavidin‐coupled Dynabeads

Abstract

An integrated giant magnetoimpedance (GMI) sensor has been used for the detection of Dynabeads® MyOne Streptavidin C1 (DMS). An Au film was sputtered onto magnetic sensing elements for the immobilization of DMS in order to develop an integrated biosensor for potentially biomedical applications. The GMI responses were measured for the detection of DMS from 0.1 µg mL−1 to 100 µg mL−1. We observed that the GMI effect was greatly improved at high frequencies owing to the presence of superparamagnetic beads. It was found that magnetic dipole fields had partly canceled each other out due to the uneven distributions and high‐density clusters of Dynabeads. High‐detection sensitivity was achieved in the detection of low concentrations of DMS. This integrated GMI sensor is well suited for detection of magnetic beads‐labeled biological components.

Magneto-Impedance Biosensor Sensitivity: Effect and Enhancement

“…If a cluster of magnetic beads forms, the adjacent magnetic fields produced by the beads would cancel each other out, resulting in a lower magnetic signal. A similar finding is shown in Figure 7c,d, where the lowest Dynabead concentration (0.1 µg/mL) shows the highest MI effect [113]. They also observed that when Dynabeads were unevenly distributed at concentrations of 1 µg/mL the MI was reduced.…”

“…They also observed that when Dynabeads were unevenly distributed at concentrations of 1 μg/mL the MI was reduced. This reduction in MI is assumed to be due to non-uniform distribution and high-level clusters beads [ 113 ]. Comparable findings have been reported, where large MI responses have been achieved at low concentrations [ 111 , 114 , 115 ].…”

“…MI effect frequency dependence for the same Dynabeads in ( c ). Figures ( a ) and ( b ) reproduced from [ 112 ] with permission from Springer Nature, Figures ( c ) and ( d ) reproduced from [ 113 ] with permission from John Wiley and Sons.…”

“…Therefore, to avoid the offset effect of the stary magnetic field, an inter-bead gap equivalent to at least the bead diameter is required, resulting in roughly 1500 × 3000 beads. [113] with permission from John Wiley and Sons.…”

Fluorescent Nanosensor for Probing Histone Acetyltransferase Activity Based on Acetylation Protection and Magnetic Graphitic Nanocapsules

“…Currently, a novel graphene nanomaterial, namely core‐shell magnetic graphitic nanocapsule (MGN), has been developed, which inherits the superior quenching ability of graphene and magnetic separation property of magnetic nanoparticles . The excellent properties of MGN show great potential in nucleic acid detection, cell enrichment, and electrochemical analysis.…”