MagQu provides a novel and efficient assay technology involving the use of magnetic beads, bio-probes, and high-sensitivity reader. Instead of utilizing sandwich-type, plan-type labeling, MagQu developed an easy-operation, wash-free, less-time-consuming, high-specificity, high-sensitivity, and customizable assays. The advanced assay platform is so-called ImmunoMagnetic Reduction (IMR) bio-assays.

The assay principle of IMR is briefly described as follows. In IMR, the reagent is a solution having homogeneously dispersed magnetic nanoparticles, which are coated with hydrophilic surfactants and bio-probes such as antibodies. Under external multiple ac magnetic fields, magnetic nanoparticles oscillate with the multiple ac magnetic fields via magnetic interaction.

Thus, the reagent under external multiple ac magnetic fields shows a magnetic property, called multiple-frequency ac magnetic susceptibility . Via the bio-probes on the outmost shell, magnetic nanoparticles associate with and magnetically label bio-molecules to be detected. Due to the association, magnetic nanoparticles become either larger or clustered. The response of these larger/clustered magnetic nanoparticles to external multiple ac magnetic fields is much less than that of originally individual magnetic nanoparticles. Thus, the magnetic susceptibility of the reagent is reduced due to the association between magnetic nanoparticles and detected bio-molecules. This is why the method is referred as ImmunoMagnetic Reduction (IMR) bio-assay.  Furthermore, the concentration of the to-be-detected bio-molecules in the sample can be detected via measuring the normalized reduction, (- ) / , of the magnetic reagent.  XacPro-E101 and XacPro-S101 probe the normalized reduction in , hereafter referred as /, to quantitatively identify the concentration of the to-be-detected bio-molecules in samples.

Ref.: "Magnetic susceptiility reduction method for magnetically labeled immunoassay", Appl. Phys. Lett. 88, 212512 (2006).