Magnetic Bead: What is it?

Magnetic beads consist of tiny iron oxide particles (20 to 30 nm), such as magnetite (Fe3O4), which are superparamagnetic. Superparamagnetic beads differ from common ferromagnets in that they only exhibit magnetic properties in the presence of an external magnetic field. This property depends on the size of the particles in the bead and enables the bead and any material bound to it to separate in suspension. Since they don’t attract each other outside of a magnetic field, they can be used without worrying about unwanted clumping.

There are many types of magnetic beads available. Different coatings and chemistries give each type of bead its binding properties that can be used for the magnetic separation of nucleic acids, proteins, or other biomolecules in an easy, efficient, and scalable manner.

This ease of use makes it easy to automate and is ideal for a range of applications including sample preparation for next-generation sequencing (NGS) and PCR, protein purification, molecular and immunodiagnostics, and even magnetic activated cell sorting (MACS).

What is magnetic separation?

Magnetic separation uses a magnetic field to separate micron-sized paramagnetic particles from a suspension. In molecular biology, magnetic beads provide a simple and reliable method to purify various types of biomolecules, including genomic DNA, plasmids, mitochondrial DNA, RNA, and proteins. The main advantage of using magnetic beads is that you can isolate nucleic acids and other biomolecules directly from crude samples as well as from a variety of different types of samples.

How does magnetic bead DNA extraction work?

Magnetic beads have been around for decades. Their potential in nucleic acid purification was recognized as demonstrated by the 1990 US patent.

After binding the DNA, an external magnetic field attracts the magnetic beads to the outer edge of the tube, immobilizing them. When the beads are immobilized, the bead-bound DNA is retained during the washing steps. Elution buffer is added, and the magnetic field is removed, releasing the DNA as a purified sample ready for quantification and analysis.

This method eliminates the need for vacuum or centrifugation, minimizes shear forces on target molecules, requires fewer steps and reagents than other DNA extraction protocols, and is suitable for use in 24, 96, and 384 well plates automation.

Comparison of Magnetic Bead Surface Chemistry and Applications



Application field

Carboxylic acid-modified magnetic beads can

Can be directly captured in conjunction with nucleic acids. 

Covalently linked

Surfaces suitable for covalent bonding. 

Affinity purification

Molecules containing amino groups can be captured. 

Nucleic acid isolation and purification


Anti-Amine Magnetic Beads

Surfaces are suitable for covalent bonding. 

Conjugation applications are like carboxylate-modified beads. 

Non-surfactant, non-protein blocked surfaces.

Low nonspecific binding.

Oligo(dT) Coated Magnetic Beads with

with mRNA poly-A tail mRNA

mRNA extraction and purification reverse transcription PCR

High stability of the hybrid colloid

cDNA library construction

NGS (RNA Sequencing)

Streptavidin-coated magnetic beads bind

Binds biotinylated ligands such as proteins, nucleic acids, and peptides. Covalently bound streptavidin coating.

Fast reaction kinetics.

Sample preparation and assay development for genomics and proteomics.

Low nonspecific binding.

High throughput and precision.

Streptavidin-blocked magnetic beads bindings

Binds biotinylated ligands such as proteins, nucleic acids, and peptides.

Molecular and Immunodiagnostics

Non-surfactant, non-protein blocked surfaces.

NGS library preparation

Non-specific binding is lower by additional blocking of non-specific binding sites compared to non-streptavidin-coated beads.


Coated Magnetic Beads

Binds biotinylated ligands such as proteins, nucleic acids, and peptides.

Sample preparation and assay development for genomics and proteomics.

Fast reaction kinetics.

Low nonspecific binding.

High throughput and precision.

Protein A/G Magnetic Beads

Binds IgA and IgG protein affinity

Affinity purification and pull-down immunoprecipitation

IgA/IgG fusion protein-based coating. Extensive binding capabilities. 

Silica Coated Magnetic Beads

Reversibly binds nucleic acids based on salt concentration. 

Nucleic acid extraction for molecular diagnostic applications such as qPCR.

Monodisperse particles in the size range 400 µm or 700 µm.

Agarose Magnetic Beads

Broad ligand selection. 

Affinity purification or capture

Porous, providing greater surface area than other magnetic beads. 



Genfine’s Magnetic Beads Product Line


Product Name Partical Size(nm) Features Website
MS01H 50-300 Virus DNA/RNA extraction. Can be used in different extraction buffers. Wide applications
MS03H 100-300 Virus/Genome extraction. Perform well in whole blood Genome.
MS07H 200-300  Virus extraction. Good monodispersion. No magnetic beads residual.
MS08H To be tested  Virus extraction. Perform well in different DNA/RNA virus extraction buffers. Good adaptability, Coming Soon
MS01C 50-300 Virus extraction beads. The Hydroxyl function group perform well in certain Buffers.
K 20-100 cfDNA extraction. Perform well in cfDNA buffer.
GF 400-1000 Genome extraction.  No magnetic beads residual. Quick reaction time. Extract high purity DNA/RNA


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