Magnetic supercluster particles for highly sensitive magnetic biosensing of proteins

Abstract

A strategy is reported to improve the detection limits of current giant magnetoresistance (GMR) biosensors by augmenting the effective magnetic moment that the magnetic tags on the biosensors can exert. Magnetic supercluster particles (MSPs), each of which consists of ~ 1000 superparamagnetic cores, are prepared by a wet-chemical technique and are utilized to improve the limit of detection of GMR biosensors down to 17.6 zmol for biotin as a target molecule. This value is more than four orders of magnitude lower than that of the conventional colorimetric assay performed using the same set of reagents except for the signal transducer. The applicability of MSPs in immunoassay is further demonstrated by simultaneously detecting vascular endothelial growth factor (VEGF) and C-reactive protein (CRP) in a duplex assay format. MSPs outperform commercially available magnetic nanoparticles in terms of signal intensity and detection limit.

Real-time temperature correction for magnetoresistive biosensors integrated with temperature modulator

“…GMR biosensors consist of multiple nanoscale layers of magnetic and nonmagnetic materials, as described previously ( Gaster et al, 2009 ; Kim et al, 2022 ). GMR biosensors with a stack of seed layer/IrMn (8)/CoFe (2)/Ru (0.8)/CoFe (2)/Cu (2.3)/CoFe (4.5)/capping layer (all thickness in nm) were fabricated in a 10 × 8 array on a silicon die (chip).…”

“…To observe binding signals, half of the GMR sensors were coated with biotinylated BSA, and the other half was treated with BSA as a negative control. The GMR sensors were prepared with a previously reported protocol ( Kim et al, 2022 ). Briefly, a GMR sensor chip was washed twice with acetone, methanol, and isopropanol.…”

Co-crosslinking strategy for dual functionalization of small magnetic nanoparticles with redox probes and biological probes

“…And these surface functionalization strategies can potentially address the dispersion stability of MNPs, particularly for these bare MNPs. On the other side, they can also provide a solution to combine these multi-functionalities of redox signal amplification or biological capture, for their use of biosensing [ 10 – 12 ]. Clearly, surface functionalization strategies played a significant role in the aid of wide MNP application.…”

Magnetic-Guided Targeted Delivery of Zerumbone/Spion Co-Loaded in Nanostructured Lipid Carrier into Breast Cancer Cells

“…Moreover, SPION is an attractive drug delivery system due to its biocompatibility, chemical stability, and inherent multifunctionality [7,8]. The versatility of SPION leads to their utilization in a wide range of biomedical applications, including magnetic resonance imaging (MRI) as a contrast agent [9], drug delivery [10], magnetic hyperthermia treatment (MHT) [11] and biosensing [12]. However, the direct application of SPION is limited by its tendency to agglomerate in biological fluids and subsequent removal by the cells of reticuloendothelial system (RES) [8,13].…”