Preparation and Characterization of Perforated SERS Active Array for Particle Trapping and Sensitive Molecular Analysis

Rigó, István; Vereš, M.; Holczer, Eszter; Hakkel, Orsolya; Deák, András; Fürjes, Péter

doi:10.3390/bios9030093

Cited by 7 publications

(6 citation statements)

References 12 publications

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“…This approach has been applied by using superhydrophobic plasmonic materials 29 and substrates with complex geometries that can concentrate, capture or trap EVs within the area of plasmonic enhancement. Researchers developed SERS substrates with a vast variety of surface geometries including micropillars, 30 nanopillars, 31 microbowls 29 and nanobowls, 32 nanoporous films, 33 and perforated pyramidal structures 34 that have allowed trapping of EVs in hot spot locations. In some cases, preparation of such substrates requires the use of laborious lithography methods, clean room, or expensive equipment.…”

Section: ■ Introductionmentioning

confidence: 99%

Complementary Metal-Oxide-Semiconductor-Based Sensing Platform for Trapping, Imaging, and Chemical Characterization of Biological Samples

Imanbekova

Saridag

Kahraman

et al. 2022

ACS Appl. Opt. Mater.

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Complementary metal-oxide-semiconductor (CMOS) imaging sensors provide the unique opportunity for combining lensless imaging with new modalities that enable sample handling and chemical characterization. In this study, we present a new CMOS-based sensing platform for trapping, imaging, and chemical characterization of samples via SERS (CMOS-TrICC). The SERS substrate is fabricated directly on a CMOS imaging sensor by depositing a thin metallic layer on top of the CMOS microlenses. SERS activity is based on square unit cell patterned, closely spaced, micrometer-sized microlenses on the surface of the imaging sensor. Morphological analysis of the surface revealed an intracavity depth of approximately 700 nm and height-dependent width ranging from a minimum of just a few nm between two lenses to a maximum of 1400 nm, with a flat valley exhibiting approximately 300 nm width at the bottom between four lenses. These morphological features concentrate electromagnetic fields into SERS hot spots and at the same time help trap nanometer-sized particles in the wells created by the microlenses. The strongest plasmonic effect is expected in the gaps between the microlenses. Simulations were used to map the distribution of the electromagnetic field enhancement on the SERS substrate surface and at a distance above it. The performance of the SERS substrate and its dependence on the silver layer thickness were examined using 4-aminotheophenol and rhodamine 6G with the experimental enhancement factor measured to be 5.0 × 10 4 . We demonstrated the use of this substrate for parallel trapping of 100 nm nanospheres and extracellular vesicles (EVs) in the gaps between the microlenses and SERS characterization of these particles in the hot spots. SERS intensities are 2 orders of magnitude higher in the nanogaps between the microlenses (intracavity area) than on top of the microlenses, and for polystyrene, they exhibited signature peaks centered at 1000 and 1600 cm −1 . SERS spectra of small EVs collected from intracavity areas where EVs were trapped show peaks known to arise from their main biochemical constituents, such as lipids, proteins, and nucleic acids. While the surface of the CMOS imaging sensor became SERS active by the addition of the metallic layer, the imaging capability is maintained and provides the opportunity for direct on-chip lensless imaging with spatial resolution limited by the pixel size, opening new directions for integrated (bio)sensing devices.

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Section: ■ Introductionmentioning

confidence: 99%

Complementary Metal-Oxide-Semiconductor-Based Sensing Platform for Trapping, Imaging, and Chemical Characterization of Biological Samples

Imanbekova

Saridag

Kahraman

et al. 2022

ACS Appl. Opt. Mater.

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“…SERS offers diverse potential applications, including environmental monitoring, bio-analyses, forensic analyses, food quality control, material characterizations, etc. [ 51 , 52 , 53 , 54 , 55 ]. Credited to its remarkable sensitivity and enhancement factor as high as 10 11 , SERS technique can enable single-molecule level detection [ 56 , 57 , 58 ].…”

Section: Introductionmentioning

confidence: 99%

Rapid Fabrication of Fe and Pd Thin Films as SERS-Active Substrates via Dynamic Hydrogen Bubble Template Method

Raj¹,

Scaglione²,

Rizzi³

2022

Nanomaterials

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Fe and Pd thin film samples have been fabricated in a rapid fashion utilizing the versatile technique of dynamic hydrogen bubble template (DHBT) method via potentiostatic electrodeposition over a copper substrate. The morphology of the samples is dendritic, with the composition being directly proportional to the deposition time. All the samples have been tested as SERS substrates for the detection of Rhodamine 6G (R6G) dye. The samples perform very well, with the best performance shown by the Pd samples. The lowest detectable R6G concentration was found to be 10−6 M (479 μgL−1) by one of the Pd samples with the deposition time of 180 s. The highest enhancement of signals noticed in this sample can be attributed to its morphology, which is more nanostructured compared to other samples, which is extremely conducive to the phenomenon of localized surface plasmon resonance (LSPR). Overall, these samples are cheaper, easy to prepare with a rapid fabrication method, and show appreciable SERS performance.

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“…After evaporating a thin gold layer, inverted pyramidal wells were e.g. used to trap a gold nanoparticle, which further increased the near-field enhancement [19]. Metal can also be evaporated onto the pyramidal silicon wells through the opening of the silicon etch mask to fabricate single inverted nanopyramids [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

“…used to trap a gold nanoparticle, which further increased the near-field enhancement [19]. Metal can also be evaporated onto the pyramidal silicon wells through the opening of the silicon etch mask to fabricate single inverted nanopyramids [19][20][21][22]. After mechanical stripping the structures show ultra-smooth surfaces, which benefits the electromagnetic enhancement at the edges and tips [23].…”

Section: Introductionmentioning

confidence: 99%

Hexagonal arrays of plasmonic gold nanopyramids on flexible substrates for surface-enhanced Raman scattering

et al. 2021

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Surface-enhanced Raman scattering (SERS) with pyramidal nanostructures increases the signal of Raman active analytes, since hotspots form at the edges and tip of a nano-pyramid under illumination. 2D hexagonal arrays of pyramidal nanostructures with a quadratic base are fabricated through cost-effective nano-sphere lithography and transferred onto elastomeric polydimethylsiloxane (PDMS). By making use of the {111} crystal plane of a silicon (100) wafer, an inverted pyramidal array is etched, which serves as the complementary negative for the gold nanostructures. Either a continuous gold thin-film with protruding pyramids or separate isolated nano-pyramids are produced. Three main fabrication strategies are presented, in which a linker molecule between the PDMS and the gold is mandatory to increase the weak Au-PDMS adhesion. 3-Mercaptopropyltriethoxysilane (MPTS) is able to bind to both PDMS and to the gold structures, thus strongly increasing stability under mechanical strain. The SERS enhancement is verified by Raman mapping of 4-mercaptobenzoic acid (4-MBA) molecules. Fabrication on a flexible substrate paves the way for future applications on curved surfaces or insitu tunable resonances.

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Preparation and Characterization of Perforated SERS Active Array for Particle Trapping and Sensitive Molecular Analysis

Cited by 7 publications

References 12 publications

Complementary Metal-Oxide-Semiconductor-Based Sensing Platform for Trapping, Imaging, and Chemical Characterization of Biological Samples

Complementary Metal-Oxide-Semiconductor-Based Sensing Platform for Trapping, Imaging, and Chemical Characterization of Biological Samples

Rapid Fabrication of Fe and Pd Thin Films as SERS-Active Substrates via Dynamic Hydrogen Bubble Template Method

Hexagonal arrays of plasmonic gold nanopyramids on flexible substrates for surface-enhanced Raman scattering

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