Aluminum Nanoholes for Optical Biosensing

Abstract

Sub-wavelength diameter holes in thin metal layers can exhibit remarkable optical features that make them highly suitable for (bio)sensing applications. Either as efficient light scattering centers for surface plasmon excitation or metal-clad optical waveguides, they are able to form strongly localized optical fields that can effectively interact with biomolecules and/or nanoparticles on the nanoscale. As the metal of choice, aluminum exhibits good optical and electrical properties, is easy to manufacture and process and, unlike gold and silver, its low cost makes it very promising for commercial applications. However, aluminum has been scarcely used for biosensing purposes due to corrosion and pitting issues. In this short review, we show our recent achievements on aluminum nanohole platforms for (bio)sensing. These include a method to circumvent aluminum degradation—which has been successfully applied to the demonstration of aluminum nanohole array (NHA) immunosensors based on both, glass and polycarbonate compact discs supports—the use of aluminum nanoholes operating as optical waveguides for synthesizing submicron-sized molecularly imprinted polymers by local photopolymerization, and a technique for fabricating transferable aluminum NHAs onto flexible pressure-sensitive adhesive tapes, which could facilitate the development of a wearable technology based on aluminum NHAs.

Critical assessment of relevant methods in the field of biosensors with direct optical detection based on fibers and waveguides using plasmonic, resonance, and interference effects

“…A survey on modifications of optical fibers and applications in various fieldsespecially diagnosticsin combination with a discussion of future challenges are given in [135]. Nanowires, nanoparticles, and nanoholes are used for biosensing [136]. A large number of types of fiber sensors are reviewed [137] and challenges and prospects are discussed recently [138].…”

Optical Biosensors for Label-Free Detection of Small Molecules

“…Barrios et al [46] demonstrated the applicability of aluminum nanohole arrays (NHAs), deposited onto a microscope coverslip, for sensing applications. The pre-polymerization mixture was deposited onto the NHAs, and the light was efficiently confined inside favoring the photopolymerization of submicron-sized MIP patterns selective to rhodamine 123 (R123), as a model template molecule.…”

“…Evaluation of the selective recognition of R123 by the imprinted polymer was carried out by fluorescence lifetime imaging microscopy with single photon timing measurements. A similar approach has been applied to the development of biosensors for the detection of biotin as a model analyte, in combination with glass, polycarbonate compact discs (PC CDs) or transferable aluminum NHAs onto flexible pressure-sensitive adhesive tapes using label-free SPR measurements [46,47].…”

Comparative Analysis on Dielectric Gold and Aluminium Triangular Junctions: Impact of Ionic Strength and Background Electrolyte by pH Variations

“…Further, aluminium can be easily manufactured and it also displays great optical and electrical characteristics. In the biosensor, aluminium utilization seems to be not preferable because of the corrosion due to oxidation and pitting problems 28 . Other than oxidation matter, aluminium is apparently unstable in acidic and alkaline conditions, which can be validated using the outcome of sensor's performance at different pH.…”