Design and Fabrication of Nanofluidic Systems with Integrated Sensing Electrodes for Rapid Biomolecule Characterization

<p>A transparent nanofluidic system with embedded sensing electrodes was designed and fabricated by integrating Atomic Force Microscopy (AFM) nanolithography, Focused Ion Beam (FIB) milling and metal deposition, and standard microfabrication processing. The fabrication process started with the evaporation of chrome/gold (Cr/Au) onto a Pyrex 7740 wafer followed by photolithography and wet etching of the microchannels. The wafer was patterned a second time to form Au microelectrodes with 15-45 micrometer separation gaps in the nanochannel region. Sensing electrodes (up to one micron wide) were then deposited using FIB to bridge the gaps. The nanochannels were realized through both AFM nanolithography and FIB milling techniques, which simultaneously cut through the electrodes and connected the microchannels. A 100-nanometer (nm) thick layer of amorphous silicon was deposited on a separate Pyrex 7740 substrate by PECVD and used to cap the nanochannel chip through anodic bonding. The completed nanofluidic system was tested successfully for flow patency by pumping Fluorescein Isothiocyanate (FITC) through the nanochannel. The average flow rate in the nanochannel was estimated by monitoring the displacement of the liquid/air interface in the microchannel. The sensing electrodes were used to perform I-V curve measurements of fluids with different electrical conductivities in the nanochannel. As a proof of concept for biomolecule characterization, negatively-charged nanobeads (20-nm yellow-green FluoSpheres®) were translocated through the nanochannel and their corresponding electrical signatures were measured by the embedded sensing electrodes. The result was in general agreement with the electrical tunneling behavior of the nanobeads.</p>

Name thesis:degree_name

Master of Science in Microelectronics-Photonics (MS)

Level thesis:degree_level

Thesis

Year dc:date.available

2013

Author dc:creator

• Busch, Taylor Bradley

Advisor dc:contributor.advisor

• Tung, Chao-Hung Steve

Contributors dc:contributor

• Vickers, Kenneth G.
• Kim, Jin-Woo

• Pure sciences
• Applied sciences
• Biomolecule characterization
• Genome sequencing
• Nanochannel
• Nanoelectrode
• Nanofluidics
• Pyrex
• Biomedical
• Fluid Dynamics
• Nanomedicine
• Nanoscience and Nanotechnology

Repository record dc:identifier

https://scholarworks.uark.edu/etd/723

OAI identifier oai:identifier

oai:scholarworks.uark.edu:etd-1722