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Metal nanowires have been prepared with segments of different materials along their lengths. These particles can be synthesized in a large number of optically distinguishable striping patterns, and thus have been referred to as barcoded nanowires. These barcoded wires can be used for encoding information such as the type of biological assay being performed on the surface of the particle. Thus they have application in multiplexed bioanalysis.
A variety of methods exist for metal and semiconductor nanowire synthesis. Of these, few are capable of producing wires with segments of different materials along the length of the wire. Templated electrodeposition has been used for production of striped metal nanowires tens to hundreds of nanometers in diameter and several microns in length. The length of each segment can be as small as tens of nanometers or as long as the entire wire. The resulting nanowires have potential application as components in self-assembled functional electronic devices. Segments of differing electronic properties (e.g., conductors, semiconductors, and even monolayers) can be incorporated to prepare building blocks for the bottom-up assembly of electronic devices.
Optically encoded (barcoded) particles also have potential applications analogous to barcodes in the retail industry, where the products are tracked by the barcode pattern. Typically, the barcode labels used on retail products are readily identifiable to the human eye. In addition to these overt tags, there is also interest in microscopic barcodes invisible to the naked eye. Striped nanowires can serve as such microscopic identifiers, and have enormous potential for use in biological sensing applications where many different bioassays must be simultaneously followed. In this last application, the barcoded nanowires perform a function analogous to the individual spots of a DNA microarray, encoding the identity of biomolecules attached to their surface.