SpheroTechnical Notes #20 - Activation Techniques for Hydroxyl Magnetic Particles

Hydroxylic particles are used to facilitate the development of immunoassays, as well as, quantitate, isolate purify and characterize proteins, cells, or various target analytes. In order to provide the benefits of hydroxyl groups, Spherotech offers SPHERO Hydroxyethyl (HEMA)/Polystyrene Copolymeric Magnetic Particles. These copolymeric particles provide a hydrophilic surface which reduces denaturation of immobilized protein. In addition, the hydroxyethyl groups hydrogen bonds with a layer of water in an aqueous solution preventing aggregation of the particles. These two characteristics translate into longer ligand stability, lower nonspecific binding potential, and a more stable particle solution compared to particles of more hydrophobic surfaces.

Although hydroxyl groups do not spontaneously reactive toward functional groups on biomolecules, they can be activated for covalent coupling by a number of known reaction mechanisms. The reactions result in covalent attachment of ligands and can be performed under aqueous or non-aqueous conditions. By utilizing non-aqueous conditions the hydrolysis of activating agents and the intermediate groups is prevented.

The SPHERO HEMA/Polystyrene Copolymeric Magnetic Particles::
- Minimize non-specificity problems and provide stable particle solutions
- Can be activated using a variety of methods for the coupling of ligands in either aqueous or non-aqueous solutions
- Yield intermediate after activation that will then bind to thiolated ligand or the amino groups in the ligand being conjugated.
- Can utilize cross-linkers that serve as spacers between the bound ligand and the particle
- Serve to expand the repertoire of molecules capable of being conjugated to magnetic beads
Select the link below to download the complete SpheroTECHNICAL NOTE. (PDF format)

SpheroTechnical Note #20 will provide the following information:
  • An introduction to the hydroxylic beads and their benefits
  • A protocol for the utilization of a maleimide-and-isocyanate crosslinker for attaching hydroxyl magnetic particles to compounds with sulfhydryl groups
  • A protocol for the activation of hydroxyl magnetic particles using imidazole carbamestes for the spontaneous binding to proteins
  • A protocol for the activation of hydroxyl magnetic particles using disuccinimidyl carbonate to create a NHS-carbonate particle