A simple, one-step method for fabricating single biologically functionalized conducting-polymer (polypyrrole) nanowire on prepatterned electrodes and its application to biosensing was demonstrated. The biologically functionalized polypyrrole was formed by the electropolymerization of an aqueous solution of pyrrole monomer and the model biomolecule, avidin- or streptavidin-conjugated ZnSe/CdSe quantum dots, within 100 or 200 nm wide by 3 mum long channels between gold electrodes on prefabricated silicon substrate. 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. The method offers advantages of direct incorporation of functional biological molecules into the conducting-polymer nanowire during its synthesis, site-specific positioning, built-in electrical contacts, and scalability to high-density nanoarrays over the reported silicon nanowire and carbon nanotube biosensors.

A facile technique for fabrication of individually addressable, conducting polymer nanowire arrays of controlled dimension, high aspect ratio, and site-specific positioning using electrodeposition between electrodes in channels created on semiconducting and insulating surfaces that can be easily scaled up is reported. In addition, the ability to create “arrays” of conducting polymer nanowires of same or different materials on the same chip has been demonstrated. The fidelity, quality, and electrical properties of single polypyrrole and polyaniline nanowires have been examined by SEM and I−V characteristics. Dendrite-free conducting polymer nanowires completely confined within the channels with full dimension control were observed. I−V characteristic of such nanowires show the ohmic nature of the contact with Au electrode.

Sol-gel-derived glasses have emerged as a new class of materials well suited for the immobilization of biomolecules. As a consequence, they are also finding new applications as platforms for chemical sensors. Room temperature (or lower) processing conditions, chemical inertness, negligible swelling effects, tunable porosity, and the high purity of sol-gel-derived glasses make them ideal for many types of sensor applications. We

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