Magnetic Particles: Their Applications from Sample Preparations to Biosensing Platforms

Abstract

The growing interest in magnetic materials as a universal tool has been shown by an increasing number of scientific publications regarding magnetic materials and its various applications. Substantial progress has been recently made on the synthesis of magnetic iron oxide particles in terms of size, chemical composition, and surface chemistry. In addition, surface layers of polymers, silica, biomolecules, etc., on magnetic particles, can be modified to obtain affinity to target molecules. The developed magnetic iron oxide particles have been significantly utilized for diagnostic applications, such as sample preparations and biosensing platforms, leading to the selectivity and sensitivity against target molecules and the ease of use in the sensing systems. For the process of sample preparations, the magnetic particles do assist in target isolation from biological environments, having non-specific molecules and undesired molecules. Moreover, the magnetic particles can be easily applied for various methods of biosensing devices, such as optical, electrochemical, and magnetic phenomena-based methods, and also any methods combined with microfluidic systems. Here we review the utilization of magnetic materials in the isolation/preconcentration of various molecules and cells, and their use in various techniques for diagnostic biosensors that may greatly contribute to future innovation in point-of-care and high-throughput automation systems.

Point-of-care diagnostics for infectious diseases: From methods to devices

“…Magnetic biosensors, which employ the magnetic phenomena of magnetic materials to achieve sensitive detections of the analytes, have received surging interests for POC detection applications in the past decades [53] , [123] , [252] . Compared with other biosensors, magnetic biosensors have a couple of advantages.…”

“…Besides, magnetic biosensors exhibit high specificity, sensitivity and high signal-to-noise ratio due to the negligible magnetic background signal of biological samples [256] , [257] , [258] . After several decades of development, there have been several classes of magnetic biosensors developed, such as giant magnetoresistance (GMR) biosensors, magnetic tunnel junction biosensors, magnetic particle spectroscopy (MPS) biosensors, and the nuclear magnetic resonance biosensors and so on [252] , [259] . Among them, GMR biosensors and MPS biosensors have been widely investigated for POC detection of infectious diseases in the past years.…”

Surface-Enhanced Raman Scattering Sensing of Transition Metal Ions in Waters

“… 23 For instance, magnetic-based extraction and preconcentration of the target analyte from complex media enable high throughput sample processing with the additional improvement of the limit of detection (LOD) by several orders of magnitude. 24 On the other hand, separation tools such as capillary techniques are beneficial for the selective quantification of multiple target analytes. 25 However, it has to be stressed that excessively extensive and laborious sample processing makes far less attractive the use of nanotechnology in decentralized analysis.…”

Affinity biosensors developed with quantum dots in microfluidic systems

“…On-chip magnetic bead manipulation designs are also utilized for the development of QD-based electrochemical and optical biosensors [ 70 ]. Magnetic beads into microfluidic platforms to sense viruses, biomolecules, cells, and environmental pollutants have been widely reported in the literature [ 113 – 116 ]. Biomolecules to detect analytes have been labeled mainly with enzymatic and fluorescent labels for their posterior detection by magnetic beads.…”