The Estapor® super paramagnetic microspheres are worldwide known as means of magnetic separation and the streptavidin -biotin interaction is very strong (Kd = 10-15M). Then, once coupled with streptavidin, our bioactivated beads provide you with one of the best tools for biomagnetic separation and purification

 

Our streptavidin coated magnetic microspheres provide an efficient solid-phase for separation or purification of all kind of biotinylated biomolecules, including antigens, antibodies or nucleic acids
from different sources such blood, sera, tissues and food.

 

An increasing number of industrial or research applications presently include :

• Immuno-assays, Chemiluminescent-assays or Radioimmuno-assays
• Molecular Biology, Cell Biology
• Microbiology and Virology
• High Throughput Screening (HTS)

 

Magnetic bioseparation or biopurification of antigens, antibodies or nucleic acids with Estapor® coated microspheres are both a simple and reproducible technique which provide an easier, faster and cheaper alternative to column purification, centrifugation or extraction with organic solvents. 

 

 

Characteristics	Advantages
Streptavidin coverage is optimized	Binding capacity is improved
Streptavidin is covalently coupled	Reagent is more stable
Estapor® microspheres are perfectly uniform	Non specific binding is really reduced
Estapor® microspheres are perfectly spherical	Aggregation problems are lower
Estapor® microspheres are encapsulated	Biomolecules are protected from iron
Estapor® microspheres have a 1µm size	Surface area and reactivity are higher
Estapor® microspheres are super paramagnetic	After attraction beads re-suspension is easier
Estapor® microspheres contain 40% of ferrite	Magnetic attraction is very fast

 

Protocol for the immobilization of biotinylated nucleic acids to Estapor® streptavidin coated microspheres

 

1°) Estapor® streptavidin microspheres should be washed twice with buffer before use. An
appropriate buffer to the desired application should be used. Nuclease-free material must be
used.
2°) Resuspend Estapor® streptavidin coated beads thoroughly (vortex) before use.
3°) Prewash the streptavidin coated beads with 10 x SSC-buffer (1.5 M NaCl, 0.15 M tri-sodium
citrate at pH 7.0). DNase and RNase inhibitors : add 15 to 20 Units.
4°) Mix the biotinylated DNA/RNA/Oligonucleotides with the streptavidin coated beads,and then
incubate the solution at room temperature for 15 min (oligonucleotides) or 30 min (longer
sequences) respectively. During this step, maintain the streptavidin-coated beads in
suspension, even their small size ensures that they remain in solution.
5°) Place the tube for 2 to 3 min in the magnetic rack. Remove the supernatant.
6°) Wash the streptavidin coated beads with bound nucleic acids, twice with 10 x SSC.
7°) Resuspend the streptavidin coated beads in an appropriate buffer according to your application.

 

 

Binding capacity

 

1 mg of Estapor® streptavidin coated beads will bind at least 400 pmole of biotinylated
oligonucleotides and more than 5 µg of biotinylated proteins.

 

Due to high COOH group density on their surface, the protein streptavidin is covalently attached to the Estapor® beads. For this reason, Estapor® streptavidin coated beads can be regenerated and reused for the same application with no significant loss of yield. Once used, Streptavidin coated beads should be stored at 4-6° C in the storage buffer - antiprotease (Trasylol®) could be added.

 

According to the evidence that microsphere requirements for capturing microbial cells (such as E.coli or Salmonella) are different from those for isolating nucleic acids (DNA, RNA or PCR products), we have launched a new program for developing smaller and larger super paramagnetic microspheres

 

Estapor's new proprietary polymerisation technology (patent pending) has recently created a new line of COOH microspheres from 0.3µm to 3.0 µm. Then, we have selected five different sizes of microspheres in order to better cover all the applications using streptavidin coated beads.

 

High surface area, high content of ferrite, high level of COOH groups and low non-specific-binding are among the main characteristics of this selection.

 

Now, Estapor® offers a complete range of streptavidin coated beads well suited for industrial or research applications involving biotinylated ligands.

 

Size (µm)	0.31	0.86	1.00	1.91	2.60
Ferrite (%)	40	55	40	13	30
Particle number (n/ml)	4.2 1011	1.6 1010	1.2 1010	2.4 109	0.8 109
Binding capacity of a biotinylated IgG (µg/mg)	7.7	7.5	6.6	4.4	3.3
Product number	BE-M08/03	BE-M08/08	BE-M08/10	BE-M08/19	BE-M08/26
Main advantages
Surface area	+++	++	++	+	+
Binding capacity	+++	+++	++	+	+
Magnetic separation	++	+++	+++	++	++++

 

Presentation 

• Particle content : 1% (10 mg/ml).
• Pack sizes : 2ml, 10ml and 50 ml. Larger volume on request.
• Product is suspended in Phosphate Buffer pH 7.4 containing bovine albumin and sodium azide
• 0.09%. 

 

Stability and Storage

 

Product must be stored at 4-6°C. Do not freeze. Product is stable for 24 months.