BeaverBeads Streptavidin Magnetic Beads, 2 um

Product Overview

BeaverBeads™ Streptavidin are superparamagnetic microspheres with streptavidin covalently coupled to the bead surface. The streptavidin–biotin interaction has a dissociation constant of about 10⁻¹⁵ M, among the strongest non-covalent bonds in biology, which makes it the standard way to capture anything that can be biotinylated: antibodies, antigens, oligonucleotides, proteins and peptides.

Because the ligand is attached covalently rather than adsorbed, it does not leach during washes. The beads are uniform in size and regular in shape, which gives predictable magnetic separation times and makes them suitable for automated, high-throughput platforms as well as manual work.

Binding capacity at 2 µm

Biotinylated single-stranded oligonucleotide (24 nt): ≥350 pmol per mg of beads. Biotinylated IgG: ≥15 µg per mg of beads. Supplied at 10 mg/mL.

Within the BeaverBeads Streptavidin family, oligonucleotide capacity is highest at the small end — 450 pmol/mg at both 300 nm and 1 µm, 350 pmol/mg at 2 µm, 300 pmol/mg at 5 µm. The 2 µm bead is the usual compromise: enough capacity for most capture work, with fast, clean magnetic pelleting that sub-micron beads cannot match.

Applications

Immunoassay and chemiluminescence. Used as the solid phase in magnetic particle chemiluminescence immunoassay (CLIA) and ELISA, capturing a biotinylated capture antibody. The manufacturer's manual gives a complete CLIA protocol using 50 µL of beads per well of a 96-well plate with 15-minute incubations at 37 °C.

Nucleic acid work. Isolation of nucleic acids, preparation of nucleic acid probes, and hybridisation capture of DNA and RNA using biotinylated probes.

Protein–nucleic acid interaction. Biotinylated DNA or RNA fragments immobilised on the beads are used to pull down and identify the proteins that bind them.

Also used for immunoprecipitation, cell sorting and phage display screening.

Coupling your biotinylated ligand

The manufacturer's procedure washes the beads three times, then incubates them with the biotinylated antibody or protein at a bead concentration of 1 mg/mL for 30 minutes at room temperature on a rotating mixer, followed by five washes. The full protocol is in the user manual under Documents.

Handling and safety

Do not freeze or dry the beads. Vortex for about 20 seconds to a uniform suspension before every use. A magnetic separator is required. The preservative contains ProClin-300 and BSA; if either interferes with your assay, wash the beads into your own buffer before starting. Keep beads and separators away from metal objects, electronic devices and implanted electronic devices such as cardiac pacemakers.

For Research Use Only. Not for use in diagnostic or therapeutic procedures. Specifications are those published by the manufacturer, BEAVER Biomedical Engineering Co., Ltd.