New superparamagnetic fluorescent particles for flow-cytometric multiplex analyses
For the simultaneous detection of different analytes, multiplex analyses with flow cytometers have proven a very efficient method in quite a number of sample types. The process relies on highly monodisperse polymer particles with distinctively graded fluorescence intensities as well as particle diameters. In order to achieve a high sample throughput, the automatization of the technology is desireable. To date, this challenge is not solved in a satisfactory manner by any of the competitors in the market. A smart way toward the automation of particle-based methods is the usage of paramagnetic beads that can be moved and directed by external magnetic fields and thus are suited for computer-aided process sequences. microParticles GmbH’s scientists now succeeded in the manufacture of 7 µm diameter superparamagnetic polymer particles with up to 12 fluorescent intensities that are distinct from each other. In combination with analogous 5 µm diameter beads, a whole range of up to 20 distinguishable superparamagnetic fluorescent particles was set up. For the coupling of antibodies to the particles they have been equipped with carboxyl functions (PS-MAG-Fluo-COOH, see figure). Our investigations also yielded a good batch-to-batch reproducibility both with respect to particle diameters and fluorescence intensities.