title: The detection of specific biomolecular interactions with micro-Hall magnetic sensors.
abstract: The detection of reagent-free specific biomolecular interactions through sensing of nanoscopic magnetic labels provides one of the most promising routes to biosensing with solid-state devices. In particular, Hall sensors based on semiconductor heterostructures have shown exceptional magnetic moment sensitivity over a large dynamic field range suitable for magnetic biosensing using superparamagnetic labels. Here we demonstrate the capability of such micro-Hall sensors to detect specific molecular binding using biotin-streptavidin as a model system. We apply dip-pen nanolithography to selectively biotinylate the active areas of InAs micro-Hall devices with nanoscale precision. Specific binding of complementarily functionalized streptavidin-coated superparamagnetic beads to the Hall crosses occurs via molecular recognition, and magnetic detection of the assembled beads is achieved at room temperature using phase sensitive micro-Hall magnetometry. The experiment constitutes the first unambiguous demonstration of magnetic detection of specific biomolecular interactions with semiconductor micro-Hall sensors, and the selective molecular functionalization and resulting localized bead assembly demonstrate the possibility of multiplexed sensing of multiple target molecules using a single device with an array of micro-Hall sensors.
authors: Department of Physics and MARTECH, Florida State University, Tallahassee, FL 32306, USA.
authors: Pradeep
authors: P
authors: Manandhar
authors: Kan-Sheng
authors: KS
authors: Chen
authors: Khaled
authors: K
authors: Aledealat
authors: Goran
authors: G
authors: Mihajlović
authors: C Steven
authors: CS
authors: Yun
authors: Mark
authors: M
authors: Field
authors: Gerard J
authors: GJ
authors: Sullivan
authors: Geoffrey F
authors: GF
authors: Strouse
authors: P Bryant
authors: PB
authors: Chase
authors: Stephan
authors: S
authors: von Molnár
authors: Peng
authors: P
authors: Xiong
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D001710:Biotin / Q000378:metabolism*; D008280:Magnetics / Q000295:instrumentation*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D019809:Streptavidin / Q000378:metabolism*
chemical_list: D001710:Biotin; D019809:Streptavidin