Single metal and conducting polymer nanowires used as chemical/bio molecular sensors

Abstract

We present the fabrication of single nanowires composed of different materials including Palladium (Pd), Polyaniline (PANI) and Polypyrrole (PPy) via electrochemical deposition. The individual nanowires have diameters within 100 nm and lengths from 3 to 10 μm. A gate-assisted growth further improves the growth and limits the size of the nanowires. Single Pd, PPy and PANI nanowires are used as sensors to detect multiple chemical gases, including hydrogen (H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ), methanol (CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> OH), and nitrogen dioxide (NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ). Each nanowire shows repeatable and reproducible sensing signals, with very low detection limits. Single PPy nanowire entrapped with anti-IgE aptamers is also fabricated with good morphology for biosensor applications. This aptamer-doped single nanowire is used to detect IgE and shows good performance in this report.