Researchers’ needs are driving advances in the biomagnetic separations market. Recognizing that binding capacity is one of the key criteria scientists use when choosing particles, Thermo Scientific launched SeraMag® SpeedBead™ streptavidin-blocked particles this month. This bead offers many of the same qualities as the SeraMag particles, but magnetic response time occurs at least two times faster, reports Aaron Craig, marketing communications specialist.
This faster response means that clinical diagnostics assays can be performed more quickly, and that particles move more quickly through viscous solutions in molecular biology, he adds. The more rapid response time is partially attributed to the greater quantity of magnetite that is added, essentially by encapsulating the original SeraMag particle with a second layer of magnetite and a surface coating.
“These beads offer medium- to high-binding capacities, up to 55 micrograms of biotinylated IgG,” Craig says.
The greatest value of the newest addition to the SpeedBead family, however, may be the particles’ ability to reduce nonspecific binding, which yields more accurate assays.
As Craig explains, nonspecific binding of lipids, proteins, etc. can interfere with assay precision and reliability. The streptavidin-blocked particles have a new surface treatment that reduces the tendency for undesired entities bind to the bead. Blocked beads minimize nonspecific binding in many applications while maintaining their specific biotin binding capacity.
SpeedBeads are 1 micron in diameter, and so have a slow settling rate minus the magnetic field, Craig says. These superparamagnetic beads are surfactant free and can be sonicated. They are encapsulated, so no iron is exposed.
Craig says the industry is subtly changing, as researchers gravitate toward kits. “Kits save time for our customers.” The Seradyn division of Thermo Fisher Scientific also develops custom beads. In that segment of the market, he says he is seeing interest in enzymatic coatings.