Nanowire-Based Electrochemical Biosensors

Abstract

We review recent advances in biosensors based on one-dimensional (1-D) nanostructure field-effect transistors (FET). Specifically, we address the fabrication, functionalization, assembly/alignment and sensing applications of FET based on carbon nanotubes, silicon nanowires and conducting polymer nanowires. The advantages and disadvantages of various fabrication, functionalization, and assembling procedures of these nanosensors are reviewed and discussed. We evaluate how they have been used for detection of various biological molecules and how such devices have enabled the achievement of high sensitivity and selectivity with low detection limits. Finally, we conclude by highlighting some of the challenges researchers face in the 1-D nanostructures research arena and also predict the direction toward which future research in this area might be directed.

Magnetic field alignment of template released ferromagnetic nanowires

“…49 For applications where site-specific location and orientation of nanostructures is required, such as electronic circuits and sensors, global magnetic alignment in conjunction with other methods for locating the nanowires onto specified positions on a device structure can assist in the orientation of nanowires. Such positioning techniques include chemical bonding via biochemical functionalization, 37,50 localized electric field assisted alignment, 26,29,30 and localized magnetic field gradients. 39 For applications of nanowires in sensors, such as for biotechnology applications, 26 where nanostructures need to make contact between electrodes, but the precise orientation of the nanowires is not significant, then magnetic alignment would be beneficial.…”

“…Such positioning techniques include chemical bonding via biochemical functionalization, 37,50 localized electric field assisted alignment, 26,29,30 and localized magnetic field gradients. 39 For applications of nanowires in sensors, such as for biotechnology applications, 26 where nanostructures need to make contact between electrodes, but the precise orientation of the nanowires is not significant, then magnetic alignment would be beneficial. For applications in other sensors, such as for magnetic field detection 51 and for building electronic components and logic circuits 52,53 that require high levels of precision in orientation and location, magnetic alignment of nanostructures alone does not provide a technical solution.…”

“…Therefore, a variety of techniques have been utilised to manipulate and control electrodeposited nanowires suspended in a solvent including thermocapillary motion of nanowire suspensions in microchannels, 25,26 electrostatics, [26][27][28] electric field, 26,29,30 and magnetic field [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] assisted alignment. Recently, magnetic field have been utilized by several researchers to control assembly and alignment of carbon nanotubes, 26,40 Ni, [31][32][33][34][35] semiconductor, 26 conductive polymer 26 nanowires, as well as metallic nanowires such as gold, 37,39 bismuth, 42 coppertin, 41 Pt, 43 and ZnO (Ref. 38) capped with Ni ends by manually drop casting a dilute suspension containing these nanowires between two electrodes predefined on a specimen by lithographic techniques and using two permanent magnets.…”

Organic Surface Modification of Silicon Nanowire-Based Sensor Devices

“…However, the main focus of these reviews is on the modification of large planar substrates, while the focus if this chapter is on SiNW-based devices. A review by Wanekaya et al contains a paragraph on the covalent functionalization of SiNWs with biomolecules (Wanekaya, 2006). Very recent reviews also include sections with brief schemes for SiNW functionalization (Shao, 2010;Tey, 2010).…”

Synthesis of brush-like CdS nanorod arrays through a novel hydrothermal reaction of simultaneous solvent-oxidation-hydrolysis

“…Over the past few years, shape control of nanomaterials has raised significant concerns in the preparation of one-dimensional (1D) nanomaterials such as nanorods, nanowires, nanotubes and nanobelts because they are expected to play an important role in fabricating nanodevices with novel electrical, magnetic and optical properties [1][2][3][4] etc. Much research has been done on CdS 1D nanomaterials because of its good catalytic performances and excellent nonlinear optical properties [5][6].…”