BeaverBeads Mag COOH Carboxyl Magnetic Polymer Beads, 300 nm

Product Overview

BeaverBeads™ Mag COOH-300 are monodisperse superparamagnetic microspheres with an Fe₃O₄ core and a hydrophilic polymer shell carrying surface carboxyl groups. At 300 nm they sit at the small end of the BeaverBeads COOH range, where the very high surface-area-to-volume ratio maximises capture efficiency per milligram of bead and the particles stay suspended long enough for homogeneous binding kinetics.

Surface carboxyls are activated with EDC and NHS and coupled through stable amide bonds to any ligand bearing a primary amine — antibodies, proteins, peptides and amine-modified oligonucleotides. The result is a custom capture reagent with the low non-specific binding and tight size distribution that quantitative immunoassays require.

How it works

Beads are washed into MES buffer at pH 5.0, activated with freshly prepared EDC and NHS for 30 minutes at 25 °C, then coupled to 50–200 µg of ligand at pH 8.0. After coupling, residual activated sites are blocked and the conjugate is washed into a storage buffer. The manufacturer's manuals under Documents give the full procedure and quenching conditions.

Applications

Magnetic chemiluminescent immunoassay (CLIA) development, immunoprecipitation, cell sorting, phage display screening, targeted nucleic acid capture, biosensor construction, and drug screening and delivery studies.

Choosing the right size

The Mag COOH series is supplied at 300 nm (this product, Cat. 70106), 500 nm, 1 µm, 2 µm and 5 µm. Carboxyl density rises with particle size in this family — roughly 60 µmol/g at 300 nm against 200–250 µmol/g at 1–5 µm — but the smaller bead gives faster, more homogeneous binding and stays dispersed longer. Choose 300 nm when binding kinetics and suspension stability matter more than absolute capacity per gram; choose the larger sizes when you need faster magnetic pelleting or higher capacity. Where an agarose matrix and much lower background are preferred, see BeaverBeads Magrose COOH.

Handling and safety

Do not freeze, dry out or centrifuge these beads — each causes irreversible aggregation and loss of surface activity. Vortex or sonicate briefly before every use; sub-micron beads settle during storage. A magnetic separator is required, and separation of 300 nm particles takes longer than for micron beads. 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.