Using Magnetic Silica for Protein and Peptide Isolation

Topics Covered

Introduction to Protein and Peptide Isolation
MagSi- Protein A and G
     MagSi-protein A order information
     MagSi Protein G Order information
MagSi-STA beads
     MagSi-STA order information
New MagSi-WCX Beads (Weak Cation Exchange)
     MagSi-WCX Order Information
     MagSi-COOH Order Information
     MagSi-NH2 Order Information
Customized products – MagCustom
     Advantages of MagCustom
     MagCustom Workflow

Introduction to Protein and Peptide Isolation

Isolation, separation and purification of proteins and peptides, as well as of other specific molecules, are commonly used in biotechnology research and production. New separation techniques, capable of treating dilute solutions or solutions containing only minute amounts of target molecules in the presence of vast amounts of accompanying compounds in both small and large-scale processes, even in the presence of particulate matter, are necessary.

A wide variety of techniques are used today involving a variety of chromatography, electrophoresis, ultra- filtration, precipitation and other procedures, whereof affinity chromatography being one of the most important techniques. However, these basic techniques have severe disadvantages over the use of magnetic nanoparticle solutions as provided here.

MagSi- Protein A and G

Protein A and protein G are recombinant proteins that bind with high affinity to the Fc portion of several classes and subclasses of immunoglobulin (IgG ´s) from a variety of species. Specific antigens are bound in a second step reversible towards the bound IgG. A following washing step and elution by pH shift generates the purified target protein under native conditions. MagSi protein A and G beads can be regenerated and reused several times (up to 10 times), incl large volume scales.

Certain applications of MagSi Protein A and G include

  • High yield protein purification
  • High yield antibody isolation
  • Immuno precipitation

The advantage of protein G and A beads, compared to streptavidin beads, is that the antibody does not need to be biotinylated and the binding is reversible. So they are ideal for protein isolation and proteomics. Having access to protein A or protein G makes it is possible to isolate immunoglobulins from many organisms (Table 1).

Table 1. Relative Affinity of Protein A and Protein G

IgG Protein A Protein G
Human Strong Strong
Mouse Strong, IgG1 weak Strong
Rat Weak Strong
Goat Weak/No binding Strong
Guinea Pig Strong Weak
Rabbit Strong Strong
Bovine Weak Strong
Sheep Weak Strong
Horse Weak Strong
Dog Strong Weak
Cat Strong No binding
Pig Strong Strong

Comparison of MagSi-protein A and G beads with Dynabeads® Protein G product >MagSi-protein A and G beads are characterized by low unspecific binding and a high binding capacity. For example 1 mg of the MagSi-protein A 600 (600 nm sized magnetic beads) bind more than 30 µg IgG and the binding capacity of the MagSi protein G beads is visualized in Figure 1.

Figure 1. Comparison of MagSi protein G with competitor bead. Lane 1: MagSi-protein G 600, lane 2: Magsi-protein G 1.0, lane 3: competitor Protein G beads. Beads subjected to same sample lysate with use of standard protocols for each product.

MagSi-protein A order information

MagSi magnetic silica particles with recombinant Protein A covalently bound to the particle surface.

Art. Nr. Product Conc. Size Volume
MD10011 MagSi-protein A 600 10mg/ml 600nm 1ml
MD11011 MagSi-protein A 600 10mg/ml 600nm 5ml
MD01011 MagSi-protein A 1.0 10mg/ml 1μm 1ml
MD02011 MagSi-protein A 1.0 10mg/ml 1μm 5ml

MagSi Protein G Order information

MagSi magnetic silica particles with recombinant Protein G covalently bound to the particle surface.

Art. Nr. Product Conc. Size Volume
MD10012 MagSi-protein G 600 10mg/ml 600nm 1ml
MD11012 MagSi-protein G 600 10mg/ml 600nm 5ml
MD01012 MagSi-protein G 1.0 10mg/ml 1μm 1ml
MD02012 MagSi-protein G 1.0 10mg/ml 1μm 5ml

MagSi-STA beads

MagSi-STA beads are magnetic silica beads coated with Streptavidin. The beads can be used in numerous biological and biochemical applications based on the very strong Streptavidin-Biotin binding. Silica beads coated with Streptavidin can be used to isolate biotinylated proteins or other biotinylated molecules out of different media.

It is easy to bind a biotinylated antibody to the MagSi-STA bead to isolate a specific target protein out of a cell lysate. The magnetic properties allow easy and quick washing steps in ELISA assays or protein isolations. In addition, since beads are in suspension – and therefore the coupled antibody – the incubation time can be shortened when compared to ELISA tests using antibody coated micro plates.


  • Isolation of biotinylated target molecules
  • Immunoassays
  • Binding of biotinylated antibodies
  • Cell bacteria isolation
  • Protein purification

The MagSi-STA beads are characterized by a high biotin uptake. The biotin uptake capacity of free fluorescein labeled biotin is 3000 – 7000 pmol/mg beads for both, the MagSi-STA 600 and the MagSi STA 1.0 beads.


This high binding capacity leads to the following advantages:

  • High target sensitivity
  • Low incubation time
  • Cost effectiveness

MagSi-STA order information

MagSi magnetic silica particles with a monolayer of high quality streptavidin covalently attached to the bead surface.

Art. Nr. Product Conc. Size Volume
MD16001 MagSi-STA 600 10mg/ml 600nm 2ml
MD18001 MagSi-STA 600 10mg/ml 600nm 10ml
MD01001 MagSi-STA 1.0 10mg/ml 1μm 2ml
MD03001 MagSi-STA 1.0 10mg/ml 1μm 10ml

New MagSi-WCX Beads (Weak Cation Exchange)

Recently amsbio have launched the MagSi-WCX (weak cation exchange) type of beads for chromatographic purification of native proteins. MagSi-WCX beads are magnetic silica beads with a high magnetic content optimized for protein and peptide separation. The high magnetic strength makes them applicable for both manual and automated/robotic fractionation, because the beads will typically collect in less than 1 minute when magnetic force is applied.

This quick and complete separation gives very good reproducibility since no beads will be lost during washing steps. Furthermore the quick bind wash and elute protocol shortens significantly the protocol time over conventional column based ion exchange chromatography. Use of magnetic beads in cation exchange chromatography allows easy scalability from ng protein/peptide scale up to mg (gr) amount of your target protein.

MagSi-WCX Order Information

MagSi magnetic silica particles with weak cation exchange surface (WCX)

Art. Nr. Product Conc. Size Volume
MD01023 MagSi-WCX 20mg/ml 1.2μm 2ml
MD04023 MagSi-WCX 20mg/ml 1.2μm 20ml


MagSi Tools are building block beads that are suitable to detect and capture and covalently your own specific target molecule, whether it is a protein, peptide, small molecule or other bio-molecule to the surface of the beads.

Low unspecific binding, easy to use protocols and unique advantages of the MagSi tools make these beads an ideal tool for your life science research project. MagSi-tools beads come with a proven, stable and robust surface chemistry. amsbio will assist you to choose the right chemistry and protocols for your specific research project.

MagSi-COOH Order Information

MagSi magnetic silica particles coated with a carboxyl group containing polymer, covalently attached to bead surface.

Art. Nr. Product Conc. Size Volume
MD16004 MagSi-S-COOH 600 10mg/ml 600nm 2ml
MD18004 MagSi-S-COOH 600 10mg/ml 600nm 10ml
MD01004 MagSi-S-COOH 1.0 10mg/ml 1μm 2ml
MD03004 MagSi-S-COOH 1.0 10mg/ml 1μm 10ml

MagSi-NH2 Order Information

MagSi magnetic silica particles with modified surface for NH2 coupling chemistry.

Art. Nr. Product Conc. Size Volume
MD16005 MagSi-S-NH2 600 10mg/ml 600nm 2ml
MD18005 MagSi-S-NH2 600 10mg/ml 600nm 10ml
MD01005 MagSi-S-NH2 1.0 10mg/ml 1μm 2ml
MD03005 MagSi-S-NH2 1.0 10mg/ml 1μm 10ml

Customized products – MagCustom

What if catalogue products do not meet your needs? Suppose you have the antibody to capture your specific cells or proteins; you have a read out system at hand to detect fluorescent dyes at different wavelengths, but the fluorescent signal is under the detection limit. We can provide a customized, rapid solution for you: MagCustom.

amsbio's tailor made magnetic and non magnetic beads are available in small scales and at reasonable prices. No matter if you have to couple one or two different fluorescent dyes, a specific peptide, protein, or antibody. We will find a solution to develop the product to your needs.

Figure 2. MagCustom toolbox. Quantum dots (green) or fluorescent dyes (red) and any other molecules (?) can be encapsulated next to the Ferro Fluids (black). On the surface different biomolecules like antibodies, proteins, streptavidin (STA), protein A or G and other biological and non- biological molecules can be attached on demand

Advantages of MagCustom

The advantages of MagCustom are:

  • Short development cycles: Speed and versatility of the manufacturing process enable us to offer beside ready to use products tailor-made particles with a wide range of features and short term development cycles on demand.
  • Various Matrix materials: Silica, Polymers, Gelatine
  • Customized encapsulation of Magnetic colloids, fluorescent dyes and quantum dots, drug and biological substances
  • Highly flexible: Magnetic / Non Magnetic basic beads and biocompatible
  • Hydrophilic / Hydrophobic substances
  • Choice of various fluorescent dyes
  • Choice of different binding groups
  • Choice of different ligand attachments
  • Various spacers in different sizes

MagCustom Workflow

To guarantee you a high standard and reliability amsbio builds up a process for handling of customer requests. The diagram on the right (example of the coupling of a specific antibody to magnetic beads of a specific size) gives you an idea of our workf low and the steps involved.

The company has developed a 3 Phase MagCustom work-flow from a simple feasibility study (Phase I) over a development study (phase II) up to production of customized products (phase III) under standardized conditions, incl. SOP management for production, QA/QC, raw material purchasing, warehousing and logistics. The table above gives you an overview on the MagCustom work-flow.


AMSBIO’s mission is to be a profitable premier provider of quality life science research reagents and services helping customers develop innovative methods, processes, products and medicines.

This is achieved by offering small and medium size manufacturers, academic groups and revenue generating biotechs a unique partnership for the global market and by providing state of the art and cost effective solutions to end users and partners.

Source: AMSBIO.

For more information on this source, please visit AMSBIO.

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