Detection of DNA by Magnetic Labels and Magnetoresistive Sensors

Jörg Schotter1,2, P.B. Kamp3, Michael Panhorst2, Monika Brzeska2, A. Becker3, and Hubert Brückl1,2 1ARC Seibersdorf research GmbH, Nano-Systemtechnologien, Donau-City-St. 1, A-1220 Vienna, Austria 2Department of Physics, University of Bielefeld, Universitätsst. 25, D-33615 Bielefeld, Germany 3Department of Biology, University of Bielefeld, Universitätsst. 25, D-33615 Bielefeld, Germany e-mail: Joerg.Schotter@arcs.ac.at URL: http://www.spinelectronics.de

For future lab-on-a-chip devices, compact and inexpensive detection units are required that directly translate the abundance of certain biomolecules into an electronic signal. By detecting specifically bound magnetic labels with magnetoresistive sensors, a versatile platform can be designed that fulfils those requirements and even enables on-chip manipulation of biomolecules by suitable magnetic gradient fields. Here, we present sensitive recognition of different types of magnetic labels by sensors based both on Giant- and Tunneling-Magnetoresistance. Hybridization experiments show that our prototype magnetoresistive biosensor can detect complex DNA with a length of one thousand base pairs down to a concentration of about 20 pM [1]. A direct comparison of our magnetoresistive and a standard fluorescent detection method clearly shows the advantage and competitiveness of our approach.