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Ocean Nanotech offers magnetic beads that are uniform and superparamagnetic for immobilization, capturing, or isolation. These magnetic beads provide an easy handling tool without tedious centrifugation, filtration, or precipitation. With a layer of biocompatible coating on the surface of these magnetic beads, Alpha Biobeads provides magnetic beads as an ideal platform with significantly low non-specific binding.

Types and Uses

A. Magnetic beads with different sizes and structures

     Ocean Nanotech offer three types of magnetic beads to fit different applications. They are Super Mag, Mono Mag, and Hi-Sur Mag.

bead type

     Super Mag are a series of magnetic beads with superparamagnetic Fe2O3 as the core and a layer of biocompatible coating on the surface. With the excellent size control techniques, Alpha Biobeads could control the superparamagnetic Fe2O3 core continuously from 50 nm to 200 nm with size distribution less than 20 %.   

     The physical size of Super Mag is larger than the critical size (~20 nm) of a superparamagnetic iron oxide nanoparticle. However, they remain superparamagnetic due to their small single crystal size (~10 nm). With the large physical size, these types of the magnetic beads could be separated or attracted by an external magnetic field much faster than the magnetic single crystals. For example, it will take around 1 or 2 minutes for a Super Mag beads with diameter of 200 nm to be separated in solution under the same magnetic field if it takes about 12 hours for a 20 nm iron oxide nanoparticle to be separated from solution. The weight percentage of magnetic content in Super Mag is >80 % to ensure the fast magnetic response.

      The fast response to a magnetic field is just one of the merits of Super Mag. Super Mag has much higher colloidal stability than the magnetic beads with size of 1 µm or larger. This characteristic make Super Mag an ideal tool for assay development or cell separation.

super mag tem

      Mono Mag is another type of magnetic beads that Alpha Biobeads can offers. By taking advantage of the monodispersed polystyrene template. Mono Mag has very narrow size distribution (<5%). The uniformity of shape, size, and surface area of Mono Mag offers rapid reaction kinetics in liquid phase and excellent accessibility. The reduced variability ensures the more reliable and reproducible results a variety of experiments.

       The weight percentage of magnetic content in Mono Mag is >60 % and Mono Mag offers the fastest magnetic response among three different types of magnetic beads from Alpha (Super Mag, Mono Mag, and Hi-Sur Mag).

mono mag tem


       In order to fit certain applications with desire of high binding capacity, Alpha Biobeads developed Hi-Sur Mag with average diameter of 1 µm (nominal). Like Mono Mag, Hi-Sur Mag also takes advantage of polystyrene template as the core. However, this type of magnetic beads has larger and rough surface area than the Mono Mag (1 µm) due to the randomly growth of magnetic content (Fe2O3) on the surface of polystyrene.

      The large surface area created by the random distributed magnetic content make this type of magnetic beads have the highest surface area amount different magnetic beads with size of 1 µm or larger. The high surface area ensures the highest binding capacity for for ligands or proteins immobilization, capturing, or isolation.

hisur mag tem