A Nanoplasmonic-Based Biosensing Approach for Wide-Range and Highly Sensitive Detection of Chemicals.

Francesco Arcadio,Caterina Eramo,Guido Chiaretti,Giovanni Porto,Chiara Perri,Nunzio Cennamo,Luigi Zeni,Aldo Minardo,Girolamo D’Agostino,Stefania Di Ronza

doi:10.3390/nano11081961

Abstract

In a specific biosensing application, a nanoplasmonic sensor chip has been tested by an experimental setup based on an aluminum holder and two plastic optical fibers used to illuminate and collect the transmitted light. The studied plasmonic probe is based on gold nanograting, realized on the top of a Poly(methyl methacrylate) (PMMA) chip. The PMMA substrate could be considered as a transparent substrate and, in such a way, it has been already used in previous work. Alternatively, here it is regarded as a slab waveguide. In particular, we have deposited upon the slab surface, covered with a nanograting, a synthetic receptor specific for bovine serum albumin (BSA), to test the proposed biosensing approach. Exploiting this different experimental configuration, we have determined how the orientation of the nanostripes forming the grating pattern, with respect to the direction of the input light (longitudinal or orthogonal), influences the biosensing performances. For example, the best limit of detection (LOD) in the BSA detection that has been obtained is equal to 23 pM. Specifically, the longitudinal configuration is characterized by two observable plasmonic phenomena, each sensitive to a different BSA concentration range, ranging from pM to µM. This aspect plays a key role in several biochemical sensing applications, where a wide working range is required.

Highlights

Planar waveguide-based sensors have shown great potential in several application fields and represent an active research area
In the nano-patterned slab waveguide covered by gold nanofilm and Molecularly imprinted polymers (MIPs) receptor layer, two different plasmonic phenomena, on the sensor surfaces interested in the functionalization process, can be excited
In Ref. [39], there was evidence only of the first kind of plasmonic phenomenon since the direction of the input light was orthogonal with respect to the sensor surface, and this working condition does not allow the excitation of surface plasmons (SPs) on the continuous gold film nearby the nanograting

Summary

Introduction

Planar waveguide-based sensors have shown great potential in several application fields and represent an active research area The development of these devices has mainly been boosted by the increasing need for rapid and automated devices to operate in several areas [1,2,3,4,5,6,7,8,9]. Several configurations exist, based on planar slab waveguide integrated on silicon (Si)-based substrate used for multiple applications, like gas sensing [18,19,20,21,22], magnetic field sensing [23,24], biological and chemical species detection [2,6,25,26,27], and so on These platforms take advantage of the technological and fabrication processes of the microelectronic industry.

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Methods

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Discussion

Conclusion