Improved biomolecular detection based on a plasmonic nanoporous gold film fabricated by oblique angle deposition.

Nak-Hyeon Kim,Munsik Choi,Jae Su Yu,Jung Woo Leem,Tae-Seong Kim,Kyung Min Byun,Tae Woo Kim

doi:10.1364/oe.23.018777

Abstract

We demonstrated an enhanced surface plasmon resonance (SPR) detection by incorporating a nanoporous gold film on a thin gold substrate. Nanoscale control of thickness and roughness of the nanoporous layer was successfully accomplished by oblique angle deposition. In biosensing experiments, the results obtained by biotin-streptavidin interaction showed that SPR samples with a nanoporous gold layer provided a notable sensitivity improvement compared to a conventional bare gold film, which is attributed to an excitation of local plasmon field and an increased surface reaction area. Imaging sensitivity enhancement factor was employed to estimate an overall sensor performance of the fabricated samples and an optimal SPR structure was determined. Our approach is intended to show the feasibility and extend the applicability of the nanoporous gold film-mediated SPR biosensor to diverse biomolecular binding events.

Highlights

Surface plasmon resonance (SPR) occurring at noble metal surfaces or metallic nanoparticles has been a great interest in a variety of fields such as nanoscale photonics [1], nanolithography [2], and biological sensing and imaging [3]
We demonstrated an enhanced surface plasmon resonance (SPR) detection by incorporating a nanoporous gold film on a thin gold substrate
Nanoscale control of thickness and roughness of the nanoporous layer was successfully accomplished by oblique angle deposition

Summary

Introduction

Surface plasmon resonance (SPR) occurring at noble metal surfaces or metallic nanoparticles has been a great interest in a variety of fields such as nanoscale photonics [1], nanolithography [2], and biological sensing and imaging [3]. With an advance of nanofabrication technology, periodic metallic nanostructures such as nanodot, nanohole and nanograting have been successfully realized using top-down processes in order to acquire designable and predictable plasmonic properties [13,14]. While such engineered way allows to assure a reliability in detection signal as well as to optimize a size, shape, and distribution of metallic nanostructures, those methods require complicated and high-priced fabrication procedure, especially for finer nanostructures. Detection of a binding event between biotins and streptavidin molecules has been tested experimentally to verify an enhanced sensitivity of a nanoporous thin gold film fabricated by OAD method

2-1. Sample preparation

2-2. SPR measurement system

2-3. Biotin-streptavidin binding interaction

Results and discussion

Conclusion