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
|
Type |
Combination |
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 |
|
|
|
NGS |
|
|
Anti-Amine Magnetic Beads |
Surfaces are suitable for covalent bonding. |
Conjugation applications are like carboxylate-modified beads. |
|
Non-surfactant, non-protein blocked surfaces. |
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|
Low nonspecific binding. |
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|
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|
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. |
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|
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. |
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|
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. |
immunoprecipitation |
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 | http://en.genfine.com/product/159.html |
| MS03H | 100-300 | Virus/Genome extraction. Perform well in whole blood Genome. | http://en.genfine.com/product/156.html |
| MS07H | 200-300 | Virus extraction. Good monodispersion. No magnetic beads residual. | http://en.genfine.com/product/160.html |
| 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. | http://en.genfine.com/product/158.html |
| K | 20-100 | cfDNA extraction. Perform well in cfDNA buffer. | http://en.genfine.com/product/157.html |
| GF | 400-1000 | Genome extraction. No magnetic beads residual. Quick reaction time. Extract high purity DNA/RNA | http://en.genfine.com/product/161.html |
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