To achieve an ultra-high sensitivity for IMR Bio-Assay, XacPro-S101 system has been developed as high-Tc SQUID-based and devoted to quantitatively measure the concentration of to-be-detected bio-molecules. SQUID is an abbreviation of superconducting quantum interference device, which is stated as the most sensitive sensor for magnetic signals.

High-Tc SQUID shows a noise level lower than that of the magnetic signal generated by magnetic beads by 2-3 orders of magnitude. Hence, SQUID can detect a tiny change in the ac magnetic susceptibility of reagents due to the clustering or conjugation of magnetic beads associating with target bio-molecules.

XacPro-S101 consists of two units: sample unit and sensing unit.
To-be-detected sample is sitting in the sample unit, while SQUID is posited in the sensing unit. A flux-transfer coil is used to connect these two units for transferring magnetic signals from sample to SQUID. XacPro-S101 is capable of quantitatively detecting the ultra-low concentration of bio-targets with aids of regents with adequate bio-functionalized magnetic beads. For example, the sensitivities in assaying human prostaglandin E1 is 10 -4 ppt ( = 10-4 pg/ml).

Ref.:
"Hyper-high-sensitivity wash-free magnetoreduction assay on bio-molecules using high-Tc superconducting quantum interference devices", J. Appl. Phys. 103, 14703 (2008).