The main reason for changing from latex to magnetic latex particles is the need for a change from an homogeneous to an heterogeneous immunoassay. The latter allows washing steps, which potentially help to improve analytical sensitivity and to reduce interference from sample components. The main consideration in shifting from a process that utilizes latex beads to one that uses magnetic latex beads will be the physical separation process itself. Applications that utilize latex beads traditionally make use of a centrifuge or, alternatively, tangential filtration. In contrast, processes that use magnetic latex beads are carried out in a biomagnetic separator. As such, it is necessary to acquire an adequate separator for the process. Ideally, this would be a homogeneous separator.
This post is about choosing the right platform for a given biomarker. If you want detailed information about this topic, download our free ebook The Advanced Guide for the use of Magnetic Beads in Chemiluminescent Immunoassays:
Practical concerns of magnetic beads
Practical concerns when working with magnetic beads include being aware that they have a stronger tendency than latex particles to fall out of solution because of their higher density. Thus, when using magnetic beads, it is important that the suspension undergoes constant mixing. Typically, this is done by placing the bead suspension on a mixer to insure that the beads remain evenly dispersed. Differently to latex particles, a ready to use magnetic bead suspension needs to be resuspended prior to use.
The chemistry of attachment to the particle is not an issue when switching from latex to magnetic latex beads, as it would be when switching over from gold nanoparticles. Both latex and magnetic latex beads use the same types of covalent bonds to attach molecules, so there is no need to seek out alternate attachment sites on the protein. A better quality in the covalent binding can be achieved with magnetic particles because of their faster separation or washing steps.
The main issue when making a switch from latex particles to magnetic latex particles is the difference in the techniques that utilize the two types of particles. Once the protocols are in place, magnetic separation processes prove to be faster and more efficient than protocols that utilize non-magnetic latex particles.
Don't forget to check these posts from our blog in order to get a deeper insight into magnetic particles and immunoassays:
- Using streptavidin magnetic beads in Chemiluminescent Immunoassays
- A great variety of magnetic particles for multiple applications
- Moving from Gold Particles to Magnetic Beads in IVD Assays
