Design, fabrication and characterization of plasmonic gratings for SERS

Romanato, Filippo; Pilot, Roberto; Massari, Michele; Ongarello, T.; Pirruccio, Giuseppe; Zilio, Pierfrancesco; Ruffato, Gianluca; Carli, Marta; Sammito, D.; Giorgis, V.; Garoli, Denis; Signorini, Raffaella; Schiavuta, Piero; Bozio, Renato

doi:10.1016/j.mee.2011.02.052

Cited by 15 publications

(13 citation statements)

References 6 publications

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“…The diameter of the laser spot is about 2 μm with the 20× objective. The slit width was set at 100 μm, unless differently specified in the text. Micro2 . An He–Ne laser (Melles Griot) at 632.8 nm is used as excitation light source, and the laser beam is coupled to a microscope (Olympus BX 40).…”

Section: Methodsmentioning

confidence: 99%

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Validation of SERS enhancement factor measurements

Pilot

Bozio

2017

J Raman Spectroscopy

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The huge signal enhancement that motivates the rapid spreading of surface‐enhanced Raman scattering (SERS) in a wide range of applications is commonly quantified by measuring the enhancement factor (EF). Concerning this important parameter, in this paper, we tackle 2 points: (a) We validate the use of a Macro Raman configuration with line focus to measure the EFs, against the more common Micro Raman one. The validation is carried out by comparing the EFs measured in the 2 configurations with the well‐established methodology, on the same set of commercial substrates. Macro Raman with line focus can be advantageous over the Micro Raman because it can provide a higher signal‐to‐noise ratio at equal laser intensity impinging on the sample (useful in sensing or analytical applications). (b) It is a common practice for practitioners validating an experiment by measuring a commercial compound, acting as a “standard,” whose properties have been already determined in the literature: To our knowledge, an equivalent “standard” does not exist for EF measurements, probably due to the reproducibility and aging issues that prevent them from being identically reproduced in different laboratories. Because the EF is the cross‐section ratio of a test molecule under SERS and normal Raman conditions, if one replaces the SERS substrate and the reference liquid with 2 commercial materials in the EF measurement procedure, this leads to the determination of another cross‐section ratio: We propose then to use the cross‐section ratio of suitable commercial materials for the validation of the instrumental procedure used to measure EFs.

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Section: Methodsmentioning

confidence: 99%

“…SERS is currently a very fast‐growing area of research that has found many applications in the field of optical plasmonic sensors . For example, it has been exploited in the detection of biological species, chemical warfare agents, pesticides, food additives, and in the fields of art preservation and forensic science .…”

Section: Introductionmentioning

confidence: 99%

Validation of SERS enhancement factor measurements

Pilot

Bozio

2017

J Raman Spectroscopy

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“…This strong increase in sensitivity (that may even allow single‐molecule detection), along with the inherent Raman fingerprint recognition capabilities, has triggered lots of interest in the scientific community, as indicated by the rise in the percentage of papers (over the total) published in this field, especially from 2000 . All aspects of SERS have been subjects of intense studies: the physical phenomena that regulate the amplification of the signal, the fabrication and optimization of the substrates, the materials suitable for SERS amplification, and its applications. SERS applications span very diverse fields, in continuous expansion.…”

Section: Introductionmentioning

confidence: 99%

SERS detection of food contaminants by means of portable Raman instruments

Pilot

2018

J Raman Spectroscopy

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Surface‐enhanced Raman scattering (SERS) has been emerging as a powerful tool for the detection of a variety of analytes due to its very high sensitivity and fingerprinting recognition capabilities. Technological progresses in the equipment for Raman analysis are contributing to its transition from a technically demanding research method to a more widely available analytical technique. In particular, the commercialization of portable or handheld instruments has opened up the possibility of performing in situ analysis. In this review, a selection of the SERS substrates that are expected to be more suitable for use in combination with portable instruments is presented: Substrates are compared, for example, in terms of performance, reproducibility, ease of fabrication, and surface area. Moreover, this paper provides a survey of the current diffusion of portable Raman instruments in the SERS detection of food contaminants: The investigation of several analytes is summarized (mainly toxins, virus, bacteria, pesticides, forbidden food dyes, and preservatives), reporting on the limits of detection and on the eventual coupling with concentration or separation techniques. A brief perspective on possible future developments of the SERS detection with portable instruments is also provided.

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“…The procedures here used for solution bioconjugation have been selected so to be economical and to be reproducible also within laboratories that are not highly equipped to perform chemical synthesis. The 5 KDa PEO conjugate prepared according to this procedure was used as a probe for complementary DNA detection using a Grating-Coupling Surface Plasmon Resonance (GC-SPR) system [ 28 , 29 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Chromatography-Free Purification of PNA-PEO Conjugates for the Functionalisation of Gold Sensors

et al. 2012

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Peptide Nucleic Acids (PNAs) linked to high molecular weight (MW) poly(ethylene oxide) (PEO) derivatives could be useful conjugates for the direct functionalisation of gold surfaces dedicated to Surface Plasmon Resonance (SPR)-based DNA sensing. However their use is hampered by the difficulty to obtain them through a convenient and economical route. In this work we compared three synthetic strategies to obtain PNA-high MW PEO conjugates composed of (a) a 15-mer PNA sequence as the probe complementary to genomic DNA of Mycobacterium tuberculosis, (b) a PEO moiety (2 or 5 KDa MW) and (c) a terminal trityl-protected thiol necessary (after acidic deprotection) for grafting to gold surfaces. The 15-mer PNA was obtained by solid-phase synthesis. Its amino terminal group was later condensed to bi-functional PEO derivatives (2 and 5 KDa MW) carrying a Trt-cysteine at one end and a carboxyl group at the other end. The reaction was carried out either in solution, using HATU or PyOxim as coupling agents, or through the solid-phase approach, with 49.6%, 100% and 5.2% yield, respectively. A differential solvent extraction strategy for product purification without the need for chromatography is described. The ability of the 5 KDa PEO conjugate to function as a probe for complementary DNA detection was demonstrated using a Grating-Coupling Surface Plasmon Resonance (GC-SPR) system. The optimized PEO conjugation and purification protocols are economical and simple enough to be reproduced also within laboratories that are not highly equipped for chemical synthesis.

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Design, fabrication and characterization of plasmonic gratings for SERS

Cited by 15 publications

References 6 publications

Validation of SERS enhancement factor measurements

Validation of SERS enhancement factor measurements

SERS detection of food contaminants by means of portable Raman instruments

Synthesis and Chromatography-Free Purification of PNA-PEO Conjugates for the Functionalisation of Gold Sensors

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