Dynabeads™ MyOne™ Streptavidin T1

This is dependent on coating or the biotinylated molecule properties. Our recommendation is that this should be tested to find optimum conditions for the specific assay.

Find additional tips, troubleshooting help, and resources within our Dynabeads Nucleic Acid Purification Support Center.

The density of Dynabeads magnetic beads is a challenging property to determine. The reason is that Dynabeads magnetic beads have a 17-37% magnetic iron oxide content in order to have a reasonable magnetic separation time, and the density of the iron oxide is about 4.9 g/cm³. Dynabeads magnetic beads are composite materials, being a mix of polymers and iron oxide, and there are very few polymers that have a density below 1.

The sedimentation rate depends on the bead diameter squared, so the sedimentation of a 1 µm bead is much slower than that of 2.8 µm. The effect of diameter on sedimentation rate is to some extent counteracted by the fact that smaller beads need to have a higher content of iron oxide for magnetic separation applications. Typically, our M-280 Dynabeads (diameter 2.8 µm) have a density of 1.4 g DS/cm³ (DS = dry substance), our M-270 Dynabeads (diameter 2.8 µm) and M-450 Dynabeads (diameter 4.5 µm) have a density of 1.6 g DS/cm³, and our MyOne Dynabeads (diameter 1 µm) have a density of 1.8 g DS/cm³.

Find additional tips, troubleshooting help, and resources within our Dynabeads Nucleic Acid Purification Support Center as well as our Dynabeads Cell Isolation and Expansion Support Center and Protein Immunoprecipitation (IP), Co-Immunoprecipitation (Co-IP), and Pulldown Support Center.

When exposed to a sample consisting of different types of molecules, any solid phase matrix can interact with these molecules due to hydrophobicity, charge or other types of interactions. It is not surprising that you get non-specific binding to the beads. This method is actually used for pre-clearing of sample and is not considered a good negative control. When pre-blocked and coated with a specific molecule, beads show a lot less non-specific binding than when they are not coated. As a negative control, you could try beads that are coated with an irrelevant molecule.

Find additional tips, troubleshooting help, and resources within ourProtein Immunoprecipitation (IP), Co-Immunoprecipitation (Co-IP), and Pulldown Support Center.

There are two methods to dissociate the non-biotinylated DNA from the biotinylated DNA strand. The following protocols are based on using 20 µL of Dynabeads Streptavidin, but are scalable. Both methods may release very small amounts of complementary biotinylated strand from streptavidin. If it is critical that no biotinylated strand is released, either adopt a different biotin modification using dual biotin (two biotin groups in sequence) or covalently bind DNA to e.g., Dynabeads M-270 Carboxylic Acid.

Using heat:

- Wash the DNA coated Dynabeads in 50 µL 1 x SSC.*
- Resuspend the beads in another 50 µL of 1 x SSC Incubate at 95 degrees C for 5 mins.
- Quickly put the tube in magnet stand for 1-2 mins and transfer the supernatant to a new tube.
- The supernatant contains your non-biotinylated DNA strand.

Using NaOH:

- Wash the DNA coated Dynabeads in 50 µL 1 x SSC.*
- Resuspend the beads in 20 µl of freshly prepared 0.15 M NaOH.
- Incubate at room temperature for 10 mins. Put the tube in magnet stand for 1-2 mins and transfer the supernatant to a new tube.
- The supernatant contains your non-biotinylated DNA strand. Neutralize the probe by adding 2.2 µL 10 x TE, pH 7.5 and 1.3 µL 1.25 M acetic acid.

Wash the Dynabeads coated with biotinylated strand once with 50 µL 0.1M NaOH, once with 50 µL of B&W buffer and once with 50 µL TE buffer.

*1 x SSC (0.15 M NaCl, 0.015 M sodium citrate. Dissolve the reagents in 800 mL water. Adjust pH to 7.0 with NaOH. Adjust the volume to 1 liter with water).

Find additional tips, troubleshooting help, and resources within our Dynabeads Nucleic Acid Purification Support Center.

Assay the supernatant for unbound molecules. This will determine the amount of molecule bound to the Dynabeads. For nucleic acids, the concentration can be checked by OD readings, or by running a gel. For proteins, the concentration in the supernatant can be determined by a spectrometer using a protein assay like BCA. Alternatively, you can label the molecule with radioactivity or fluorescence and measure the concentration of molecule directly on the beads (former) or in the supernatant (latter).

Find additional tips, troubleshooting help, and resources within our Dynabeads Nucleic Acid Purification Support Center.