Gallium chiral nanoshaping for circular polarization handling

Cuscunà, Massimo; Manoccio, Mariachiara; Esposito, Marco; Scuderi, M.; Nicotra, Giuseppe; Tarantini, Iolena; Melcarne, Angelo; Tasco, V.; Losurdo, María; Passaseo, A.

doi:10.1039/d0mh01078b

Cited by 10 publications

(15 citation statements)

References 63 publications

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“…This depends on the relative core-shell size and on the interplay between nanostructure shape and size and inspecting wavelength. In our speci c case, a decay length of 128nm is expected for the plasmonic eld 52 at the CD peak of 500nm through the shell, by considering the optical dispersion of the Pt-based core 41 and of the P-oPD shell (Supporting gure S2). Therefore, we can assume that the measured shell thickness of 12nm still supports the plasmon propagation out to the nanosystem surface.…”

Section: Resultsmentioning

confidence: 99%

Chip-Based Chiral 3D Metamaterial with Functional Core-Shell Architecture for Femtomolar Biodetection

Manoccio¹,

Esposito²,

Primiceri³

et al. 2021

Preprint

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Advanced sensing tools capable to detect extremely low concentrations of circulating biomarkers can open unexplored routes towards early diagnostics of diseases and their progression monitoring. Plasmonic sensors are an emerging technology enabling different optical effects that can be used as molecular tracking solutions. Here we demonstrate the sensing capabilities of a chip-based metamaterial, combining the 3D chiral geometry with an optically functional core-shell architecture. The sensor can be easily handled and exhibits reliability and stability during the whole functionalization and analytical procedure thanks to the on-chip format. The system shows a linear shift of circular dichroism spectrum upon interaction with different concentrations of TAR DNA-binding protein TDP-43, a clinically relevant biomarker for neurodegenerative disease screening. The measurements were performed in spiked solution as well as in human serum, with concentrations from 1pM down to 10fM, a range not accessible with commonly used immunological assays and that can thus open new perspectives for disease knowledge and early diagnostics.

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Section: Resultsmentioning

confidence: 99%

Chip-Based Chiral 3D Metamaterial with Functional Core-Shell Architecture for Femtomolar Biodetection

Manoccio¹,

Esposito²,

Primiceri³

et al. 2021

Preprint

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“…[ 26 ] However, it is fundamentally challenging to sculpture liquid metals in a chiral nano‐shape under ambient conditions to generate chiral plasmonics in the UV–vis–NIR region, which are highly desired for advanced optical and biological applications. To the best of our knowledge, there was only one report on using focused ion beam‐induced deposition to constrain Ga cores in a helical shell formed by decomposition of dielectric precursors, to impose the chiroplasmonics on Ga. [ 27 ] Fabrication of chiral liquid metals and investigation of their optical activity are in its infancy.…”

Section: Introductionmentioning

confidence: 99%

Nanohelix‐Induced Optical Activity of Liquid Metal Nanoparticles

Yang¹,

Lin

et al. 2022

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Liquid metals (such as gallium or Ga) exist in liquid states under ambient conditions and are hardly sculpted in chiral structures. Herein, through electron‐beam evaporation of Ga, hemispherical achiral Ga nanoparticles (NPs) are randomly immobilized along helical surfaces of SiO2 nanohelices (NHs), functioning as a chiral template. Helical assembly of Ga NPs shows chiroplasmonic optical activity owing to collective plasmon–plasmon interactions, which can be tuned as a function of a helical SiO2 pitch (P) and the amount of Ga evaporated. At a P of ≈150 nm, the chiroplasmonic optical activity, evaluated with anisotropic g‐factor, can be as large as ≈0.1. Because the SiO2 NHs and Ga NPs have high environmental stability of nanostructures, the chiroplasmonic optical activity shows excellent anti‐aging stability, despite slight blue shift and chiroplasmonic degradation for the first 2 weeks. Spontaneous oxidation of the Ga NPs enables the formation of dense Ga2O3 layers covering Ga cores to prevent further oxidation and thus to stabilize the chiroplasmonic optical activity. This work devises an alternative approach to impose optical activity onto Ga NPs, providing an additional degree of freedom (i.e., chirality) for Ga‐based flexible electronic devices to develop advanced applications of 3D display, circular polarizers, bio‐imaging, and bio‐detection.

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“…Core–shell nanosystems combining materials with different sign permittivities (i.e., metals with dielectrics) are expected to exhibit different effects on absorption and scattering at their resonance frequency and to modify the electric field distribution around the nanostructures. − This depends on the relative core–shell size and on the interplay between nanostructure shape and size and inspecting wavelength. In our specific case, a decay length of 128 nm is expected for the plasmonic field at the CD peak of 500 nm through the shell by considering the optical dispersion of the Pt-based core and of the P-oPD shell (Figure S2). Therefore, we can assume that the measured shell thickness of 12 nm still supports the plasmon propagation out to the nanosystem surface.…”

mentioning

confidence: 96%

“…This depends on the relative core-shell size and on the interplay between nanostructure shape and size and inspecting wavelength. In our specific case, a decay length of 128nm is expected for the plasmonic field [45] at the CD peak of 500nm through the shell, by considering the optical dispersion of the Pt-based core [21] and of the P-oPD shell (supporting figure S2). Therefore, we can assume that the measured shell thickness of 12nm still supports the plasmon propagation out to the nanosystem surface.…”

mentioning

confidence: 98%

“…Our work proposes a compact metamaterial with chiral properties as a novel optical biosensing concept, with sensitivity of about 800nm/RIU and FOM= 1276 RIU -1 , and capable to detect TDP-43 protein concentrations between 1pM and 10fM, even in the complex human serum fluid, thanks to the background-free differential signal. Further improvement in sensitivity can be envisioned thanks to the size-, geometry-and material-dependent engineering of the sensor [45,57] , leading to even more pronounced bisignated circular dichroism (in the degree level and beyond), with steeper stop bands, for larger and easier-to-detect spectral shifts. Being a miniaturized photonic component, it can be embedded within a portable point of care system, with a simple integrated optical read out, considering that it works in transmittance under normal incidence conditions, thus not requiring complex excitation geometries.…”

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confidence: 99%

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Femtomolar Biodetection by a Compact Core–Shell 3D Chiral Metamaterial

et al. 2021

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Highly sensitive and selective label free devices for real-time identification of specific biomarkers are expected to significantly impact the biosensing field. The ability of plasmonic systems to confine the light in nanometer volume and to manipulate it by tuning the size, shape and material features of the nanostructures, makes these systems promising candidates for biomedical devices. In this work we demonstrate the engineered sensing capabilities of a compact array of 3D metal dielectric core-shell chiral metamaterial. The intrinsic chirality of the nano-helices makes the system circular polarization dependent and unaffected by the background interferences, allowing to work even in complex environment. The core-shell architecture enhances the sensing properties of the chiral metamaterial on both in the far and near field, also offering a large surface to molecular immobilization. With our system we recorded sensitivity of about 800nm/RIU and FOM= 1276 RIU -1 . The sensing abilities of the system is demonstrated with the detection of the TAR DNA-binding protein 43 (TDP-43), a critical biomarker for the screening of neurodegenerative diseases. In particular, the sensor was tested in different environments, such as human serum, with concentrations ranging from 1pM down to 10fM, opening new perspectives for novel diagnostic tools.

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Gallium chiral nanoshaping for circular polarization handling

Abstract: In this work we report the local growth of ordered arrays of 3D core-shell chiral nanohelices based on plasmonic gallium metal. The structures can be engineered in a single step...

Cited by 10 publications

References 63 publications

Chip-Based Chiral 3D Metamaterial with Functional Core-Shell Architecture for Femtomolar Biodetection

Chip-Based Chiral 3D Metamaterial with Functional Core-Shell Architecture for Femtomolar Biodetection

Nanohelix‐Induced Optical Activity of Liquid Metal Nanoparticles

Femtomolar Biodetection by a Compact Core–Shell 3D Chiral Metamaterial

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