This will challenge and hopefully refute the misconception that only semiconducting neither nanowires are feasible for sensing.Currently the emergent field of nanowire systems is strongly dominated by the work on semiconducting nanowires, with silicon nanowires in field-effect transistor Inhibitors,Modulators,Libraries (FET) configurations as the obvious current system of choice [1,4�C6]. The favorable electrical properties of certain materials containing e.g., silicon [6�C9], gallium [10], cadmium [11,12], titanium [13], or carbon (i.e., carbon nanotube-based FET devices) [4,5] have yielded promising results in chemical sensing, biosensing and integrated electronics. Such nanowires represent very attractive bioelectrochemical transducer components, since their conductance is sensitive to surface perturbations induced by biochemical analytes [14,15].

Nanowires have earned so much attention that Roy et al. related nanowire-based systems to a paradigm Inhibitors,Modulators,Libraries shift in biosensing, but their focus seems only to extend to electrical sensing systems [4]. Proposed here is a new combination of sensing techniques at the nanoscale itself enabled by the design and implementation of arrays of gold and silver nanowires to harness the combined advantages of the wire array��s optical response and electrically conductive nature. In this work two types of large-scale Inhibitors,Modulators,Libraries noble-metal nanowire arrays, evaporated and particle-based, were fabricated.Analogous to plasmonic nanoparticle or nanohole systems [16�C18], plasmonic nanowires exhibit characteristic optical resonance around the visible wavelength, known as localized surface plasmon resonance (LSPR).

The resonance wavelength and field strength is dependent on the material, size, shape, separation from other plasmonic structures (e.g., periodic gaps between nanowires) and surrounding medium. For biosensing, the adsorption of biomolecules within the enhanced field is detected as a resonance peak shift, since the adsorbed molecules have Inhibitors,Modulators,Libraries a higher refractive index than the surrounding solution. Compared to bulk metal, charge density oscillations in metallic nano-objects are confined in all directions where the structural dimension is significantly smaller than excitation wavelength [19]. Thus, nanoparticles demonstrate a case of total confinement, but nanowires are a special geometric case with a 1-D length axis that can be regarded as infinitely long compared to their width.

Due to the Anacetrapib missing confinement along the length axis, localized plasmon oscillations are restricted to the plane perpendicular to the length axis. Thus, LSP modes in nanowires can only be excited selleck chem by the component of polarized light perpendicular to the wire [20].Yet at present there is a fundamental lack of understanding of the exact and predictable response of nanowires or the response of environments surrounding nanowires upon stimulation.