Influence of Random Plasmonic Metasurfaces on Fluorescence Enhancement.

Veronica Anăstăsoaie,Dana Cristea,Adrian Dinescu,Gabriel Craciun,Cristian Kusko,Iuliana Mihalache,Catalin Parvulescu,Roxana Tomescu,Stefan Caramizoiu

doi:10.3390/ma15041429

Abstract

One of the strategies employed to increase the sensitivity of the fluorescence-based biosensors is to deposit chromophores on plasmonic metasurfaces which are periodic arrays of resonating nano-antennas that allow the control of the electromagnetic field leading to fluorescence enhancement. While artificially engineered metasurfaces realized by micro/nano-fabrication techniques lead to a precise tailoring of the excitation field and resonant cavity properties, the technological overhead, small areas, and high manufacturing cost renders them unsuitable for mass production. A method to circumvent these challenges is to use random distribution of metallic nanoparticles sustaining plasmonic resonances, which present the properties required to significantly enhance the fluorescence. We investigate metasurfaces composed of random aggregates of metal nanoparticles deposited on a silicon and glass substrates. The finite difference time domain simulations of the interaction of the incident electromagnetic wave with the structures reveals a significant enhancement of the excitation field, which is due to the resonant plasmonic modes sustained by the nanoparticles aggregates. We experimentally investigated the role of these structures in the fluorescent behaviour of Rhodamine 6G dispersed in polymethylmethacrylate finding an enhancement that is 423-fold. This suggests that nanoparticle aggregates have the potential to constitute a suitable platform for low-cost, mass-produced fluorescent biosensors.

Highlights

There is currently a growing need in the biomedical field to find reliable, fast and low-cost methods for monitoring intermolecular interactions, cancer detection and cell study
To understand the fluorescence enhancement in our samples, we examined the strucunderstand the fluorescence enhancement in our samples, weregarded examined the turesTo formed by the deposition of the thin metallic films
Since these nanoparticles can be described in terms of two contributing phenomena: the local electromagnetic field present resonant plasmonic modes, the fluorescence enhancement occurring between nanoparticles leading to an increase of the excitation rate enhancement

Summary

Introduction

There is currently a growing need in the biomedical field to find reliable, fast and low-cost methods for monitoring intermolecular interactions, cancer detection and cell study. A method to increase the response of the biosensors is to employ the effect of metasurfaces upon the fluorescence enhancement (FLEN) offering the advantages of a fast and sensitive detection for various biological samples such as proteins and antibodies [2,3,4,5,6,7,8,9,10,11], DNA [12,13,14,15,16,17], cells [18,19], and cancer biomarkers [20,21,22,23]. In the last few years, it was demonstrated that they have the potential to control both the propagation and the emission of light at the nanoscale as well

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Conclusion