Magnetic beads are a key tool used to ensure convenience and reliability for molecular applications and immunodiagnostics.
However, in order to ensure fast, reliable results, it is crucial to understand the key considerations for each magnetic bead characteristic in order to troubleshoot problems as they arise.
This infographic deciphers how each characteristic influences magnetic bead separation and explores strategies to achieve optimal performance.
Download this infographic to explore top tips concerning:
- Bead size, surface area and concentration
- Parking area and magnetic response
- Sedimentation and aggregation
Troubleshooting
magnetic beads
Mastering magnetic bead characteristics
Considerations Top tips
The collective surface area of beads in solution provides
the functionality, essentially the binding capacity of
the assay.
For efficiency and performance, surface area should be
adjusted to meet specific requirements. If it is too large,
there is a risk of nonspecific activity. If it is too small, the
yield or capacity is compromised.
Surface area is often extrapolated based on the bead size,
assuming a smooth surface and near spherical shape.
Actual measurement can be via Brunauer, Emmett, and
Teller (BET) analysis.
Considerations Top tips
Magnetic particles have a range of sizes from less than
100 nm to more than 100 µm.
Larger beads have bigger surface areas individually, but
collectively, smaller beads have a larger surface area
because there’s less space between them.
There are two main options:
• Monodispersed: beads with similar sizes
• Polydispersed: beads with a range of sizes
You can measure bead size by laser diffraction using
a particle size analyzer or a dynamic light scattering
system, both of which will provide size distribution data.
Electron microscopy is also used to look at beads on an
individual level.
Considerations Top tips
Speed to magnet, or magnetic response, is determined
by the magnetic moment of the beads and their
concentrations. For viscous solutions, faster beads are
preferred. When collecting beads, ensure that all beads
have reached the magnet for consistent results.
Magnetic response rate can be measured with optical
systems such as a spectrophotometer or a Sepmag
separation system. Remember that higher concentrations
of beads travel faster, so use projected assay conditions to
measure magnetic response effectively
