Magnetic Bead Based Detection of Biomarkers by Phase Shift Measurement in Complex Sample Matrices
Stefan Scheuermann,
Researcher,
Fraunhofer IPA
[FROM SPEAKER] In clinical chemistry, the direct analytical detection of biomarkers in complex samples like whole blood still presents an enormous obstacle to overcome in order to provide rapid and highly specific biodetection systems for diagnostics. One main problem is high background of these samples preventing direct quantification by intensity measurements. Especially biomarkers for cardiovascular diseases - the leading cause of death globally - represent an important role in clinical diagnostics. In this research we focus on the detection of cardiac Troponin (cTn), a highly specific and sensitive biomarker for myocardial infarction. The detection technology is based on alternating magnetic fields forcing functionalized magnetic particles directed against cTn to oscillate within a sample container. Binding events of functionalized magnetic particles with cTn molecules lead to an increased load of cTn on the magnetic particles surface. This rise in inertial load of the magnetic particles results in delayed response to the alternating magnetic fields. The payload of magnetic beads in presence of cTn is further enhanced by sandwich formation with non-magnetic beads to create large phase shifts. Detection of the shift in response time is proportional to the concentration of cTn in the sample. We could demonstrate the capability of this technology to detect directly signals in blood in the range of available high sensitive assays while sample processing and measurements was rapid and simple.
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