Magnetic Bead—Magic Bullet

Abstract

Microfluidics is assumed to be one of the leading and most promising areas of research since the early 1990s. In microfluidic systems, small spherical magnetic particles with superparamagnetic properties, called magnetic beads, play an important role in the design of innovative methods and tools, especially in bioanalysis and medical sciences. The intention of this review paper is to address main aspects from the state-of-the-art in the area of magnetic bead research, while demonstrating the broad variety of applications and the huge potential to solve fundamental biological and medical problems in the fields of diagnostics and therapy. Basic issues and demands related to the fabrication of magnetic particles and physical properties of nanosize magnets are discussed in Section 2. Of main interest are the control and adjustment of the nanoparticles’ properties and the availability of adequate approaches for particle detection via their magnetic field. Section 3 presents an overview of magnetic bead applications in nanomedicine. In Section 4, practical aspects of sample manipulation and separation employing magnetic beads are described. Finally, the benefits related to the use of magnetic bead-based microfluidic systems are summarized, illustrating ongoing questions and open tasks to be solved on the way to an approaching microfluidic age.

Advances in Magnetic Nanoparticles for Biomedical Applications

“…Parallel to the boom of LOC, nanomaterials attracted large attention in the scientific community and have been combined with these platforms to improve the analytical performance and overcome the frequent constraint inherent to miniaturization in terms of sensitivity and selectivity, especially when concerning the analysis of real samples . This is mostly related to their superior surface‐to‐volume area for further surface modification or functionalization compared to flat surfaces or macroscaled particles.…”

“…This is mostly related to their superior surface‐to‐volume area for further surface modification or functionalization compared to flat surfaces or macroscaled particles. This modification can be performed in order to modify a wide range of surface properties including roughness, hydrophilicity, surface charge, surface energy, biocompatibility, reactivity, among others . In particular, the use of MNPs in LOC systems provides new possibilities of capturing, transporting, labeling, and detecting entities in complex aqueous systems, as they can be influenced and guided by an external magnetic field by means of permanent magnet or electromagnets, which is independent of any other biological, microfluidic, or chemical procedures .…”

Magnetic Beads in Marine Toxin Detection: A Review

“…Magnetic beads (MBs) are particles that consist of magnetite (Fe 3 O 4 ) or maghemite (mostly in the face-centered cubic crystal modification γ-Fe 2 O 3 ) and they have a superparamagnetic or a ferromagnetic behaviour, depending on their size and magnetic content [9]. Superparamagnetism is a particular kind of magnetism that occurs in sufficiently small ferromagnetic or ferrimagnetic particles, which exhibit magnetic properties only when placed in a magnetic field, with no residual magnetism once the magnetic field is removed or switched off.…”

Evaluation of bone marrow microenvironment could change how myelodysplastic syndromes are diagnosed and treated

“…Recent advances in immunomagnetic sorting methods have enabled the development of water-dispersible beads and no-wash detachment of the magnetic beads after cell isolation (44,45). These innovations might prevent the indirect activation or phenotypic changes secondary to the application of the technique in cases where a positive selection is desired.…”