The objective of this thesis is to introduce and demonstrate a novel magnetic bead detector based on inductive detection at the ferromagnetic resonance (FMR) frequency for use in bio-sensing applications. Detection ability is demonstrated through theoretical arguments, numerical computer simulations, and experimental characterization of micro-fabricated detectors.
The detector is composed of two uniplanar rf waveguides (coplanar waveguide and slotline) terminated together at a short-circuit junction, which serves as the sensitive area.
Experimental characterization of a micro-fabricated junction gives a signal ranging between 1 microvolt/volt and 12 microvolts/volt, depending on the number of beads at the junction as well spatial distribution of the beads. The locations around the tips of the CPW were shown to be the most sensitive.
A more complex rf circuit design was created employing the detection junction, and detection of magnetic beads was successfully shown at rf frequencies around 6 GHz in this configuration. Due to lack of FMR characterization data for magnetic beads in the literature, several varieties of magnetic beads were characterized using a CPW transmission line and custom apparatus to determine FMR properties. Finally, successful detection of magnetic beads was demonstrated in a system-level integration experiment employing the detector junction in combination with microfluidics and bio-chemical surface modifications. / Graduation date: 2010
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/12308 |
| Date | 03 June 2009 |
| Creators | Ghionea, Simon |
| Contributors | Dhagat, Pallavi |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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