Gold nanorod-based localized surface plasmon resonance biosensors: A review

Abstract

Noble metal nanoparticle-based localized surface plasmon resonance (LSPR) is an advanced and powerful label-free biosensing technique which is well-known for its high sensitivity to the surrounding refractive index change in the local environment caused by the biomolecular interactions around the sensing area. The characteristics of the LSPR effect in such sensors are highly dependent on the size, shape and nature of the material properties of the metallic nanoparticles considered. Among the various types of metallic nanoparticles used in studies employing the LSPR technique, the use of gold nanorods (GNRs) has attracted particular attention for the development of sensitive LSPR biosensors, this arising from the unique and intriguing optical properties of the material. This paper provides a detailed review of the key underpinning science for such systems and of recent progress in the development of a number of LSPRbased biosensors which use GNR as the active element, including an overview of the sensing principle, the synthesis of GNRs, the fabrication of a number of biosensors, techniques for surface modification of GNRs and finally their performance in several biosensing applications. The review ends with a consideration of key advances in GNR-based LSPR sensing and prospects for future research and advances for the development of the GNR-based LSPR biosensors. Contents

Synthesis methods of gold nanoparticles for Localized Surface Plasmon Resonance (LSPR) sensor applications

“…The excitation of LSPR occurred when a charge separation happened between the free electron and ionic metal core due to the interaction between the electric field of light and free electron in the nanoparticles. Thus, the restoring force (Coulomb repulsion among the free electron) forced the free electron to shift in different direction [19].…”

Full alignment of dispersed colloidal nanorods by alternating electric fields

“…Although use can be made of the anisotropic properties of single nanorods, 2,7,8 applications such as polarized light emitting diodes, 9 photovoltaic energy conversion, optical sensors or switches [10][11][12][13] require layers or volumes with large ensembles of aligned nanorods. In this context, various methods for the collective alignment of colloidal nanorods have been explored.…”

Anisotropic Gold-based Nanoparticles: Preparation, Properties, and Applications

“…49,50 This spectral change is applicable in the qualitative sensing of various molecules. 51,52 These sensing applications were a variation of Mirkin's method that used spherical gold nanoparticles, 53 but the sensitivities were improved because of the unique spectroscopic properties of gold nanorods.…”