Electrochemical plasmonic sensors

Abstract

The enormous progress of nanotechnology during the last decade has made it possible to fabricate a great variety of nanostructures. On the nanoscale, metals exhibit special electrical and optical properties, which can be utilized for novel applications. In particular, plasmonic sensors including both the established technique of surface plasmon resonance and more recent nanoplasmonic sensors, have recently attracted much attention. However, some of the simplest and most successful sensors, such as the glucose biosensor, are based on electrical readout. In this review we describe the implementation of electrochemistry with plasmonic nanostructures for combined electrical and optical signal transduction. We highlight results from different types of metallic nanostructures such as nanoparticles, nanowires, nanoholes or simply films of nanoscale thickness. We briefly give an overview of their optical properties and discuss implementation of electrochemical methods. In particular, we review studies on how electrochemical potentials influence the plasmon resonances in different nanostructures, as this type of fundamental understanding is necessary for successful combination of the methods. Although several combined platforms exist, many are not yet in use as sensors partly because of the complicated effects from electrochemical potentials on plasmon resonances. Yet, there are clearly promising aspects of these sensor combinations and we conclude this review by discussing the advantages of synchronized electrical and optical readout, illustrating the versatility of these technologies.

Single-Particle Plasmon Voltammetry (spPV) for Detecting Anion Adsorption

“…7-10 As demonstrated via ensemble spectroscopy, nanoparticle plasmons report on their local dielectric environment (nanometer range), 11-13 and thus make ideal candidates for electrochemical reaction sensing. 4,10,[14][15][16][17][18][19][20] We seek to develop an optical method for monitoring electrochemical reactions at individual nanoparticles that would allow parallel monitoring of many nanoparticles in situ.Potential-controlled sulfate ion adsorption to gold is useful for demonstrating plasmonbased sensing because there are multiple benchmark examples. Bulk spectroelectrochemical methods have been successful in sensing sulfate adsorption on planar gold electrodes via second harmonic generation (SHG), 21 two dimensional Fourier transform infrared spectroscopy (2D FTIR), 22 and surface enhanced Raman spectroscopy (SERS).…”

An Electronic Sensor for Detection of Early-Stage Biomarker/s for Ovarian Cancer

“…We have also attempted to address the question that has been raised by our previous work: Whether the presence of redox probe is important when using faradic EIS (fEIS) as a detection technique. This issue has recently been raised and discussed by other investigators [35]. In this study, we have addressed this issue by proposing an unconventional mechanism of detection for EIS and explaining how it works.…”

“…Our work generated a discussion of whether it is important to use a redox probe at all [35], as also discussed by other groups [38]. Therefore, we decided to test the effect of the presence/absence of redox probe on the sensor response with a DC bias.…”

Electroanalytical Sensor Technology

“…At present the majority of electrochemical sensor development is application orientated which has resulted in the extreme miniaturisation of sensing devices. This is in a large way due to the concurrent advances in nanotechnology which has allowed the fabrication of novel sensors possessing signal transduction mechanisms that exploit the unique physical phenomena of the nanoscale [81]. These sensors may utilise, for example, the spectroscopy of plasmonic nanoparticles, the deflection of cantilevers and the conductivity of nanowires [81,82].…”