Nanowire Sensors and Arrays for Chemical/Biomolecule Detection
M. Yun, C. Lee, R.P. Vasquez, K. Ramanathan, M.A. Bangar, W. Chen, A. Mulchandan and N.V. Myung
Jet Propulsion Laboratory, US
nanowire sensor, biosensor
We report electrochemical growth of nanowire sensors using e-beam patterned electrolyte channels, potentially enabling the controlled fabrication of individually addressable arrays. The electrodeposition technique results in nanowires with controlled dimensions, positions, alignments, and chemical compositions. Using this technique, we have fabricated single palladium nanowires with diameters between 75 nm and 350 nm and conducting polymer nanowires (i.e. polypyrrole and polyaniline) with diameters between 100 nm (Fig. 1) and 500 nm. Using these single wires, we have successfully demonstrated gas sensing with Pd nanowires and pH sensing with polypyrrole nanowires. In addition, a simple one-step method for fabricating single biologically-functionalized conducting polymer (polypyrrole) nanowire on prepatterned electrodes and its application to biosensing was also demonstrated. The biologically functionalized polypyrrole nanowires were formed by the electropolymerization of pyrrole monomer with entrapped biomolecules in single steps (e.g., avidin, biotin and streptavidin conjugated CdSe quantum dots). When challenged with biotin-DNA, the avidin- and streptavidin-polypyrrole nanowires generated a rapid change in resistance to as low as 1 nM demonstrating the utility of the biomolecule-functionalized nanowire as biosensor. In addition, we have successfully demonstrated a biochemical sensor capable of detecting glucose and are investigating a biomedical sensor capable of detecting thyroid hormones using bundled nanowires.
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Nanotech 2005 Conference Program Abstract