Barik, Avijit2019-04-092019-04-092017-02https://hdl.handle.net/11299/202429University of Minnesota Ph.D. dissertation. February 2017. Major: Biomedical Engineering. Advisor: Sang-Hyun Oh. 1 computer file (PDF); xi, 167 pages.Performance of surface-based plasmonic biosensors is often plagued by diffusion-limited transport, which complicates detection from low-concentration analytes. By harnessing gradient forces available from the sharp metallic edges, tips or gaps that are often found in the plasmonic sensors, it is possible to combine a dielectrophoretic concentration approach to overcome the mass transport limitations. A transparent electrode is integrated with the plasmonic substrates that allow dielectrophoresis without interfering with the label-free sensing schemes such as surface plasmon resonance or Raman spectroscopy. Furthermore, by shrinking the gap between gold electrodes to sub-10 nm, we show ultralow-power trapping of nanoparticles and biomolecules. Reducing the operating voltages diminishes Joule heating, bubble formation and electrochemical surface reactions - hurdles associated with traditional electrodes for dielectrophoresis. The ultralow power electronic operation combined with plasmonic detection has potential in high-density on-chip integration and portable biosensing.enBiosensorsDielectrophoresisMass transportNanogap electrodesNanoparticle trappingPlasmonicsThesis or Dissertation