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Temperini ME, Polito R, Intze A, Gillibert R, Berkmann F, Baldassarre L, Giliberti V, Ortolani M. A mid-infrared laser microscope for the time-resolved study of light-induced protein conformational changes. Rev Sci Instrum 2023; 94:064102. [PMID: 37862502 DOI: 10.1063/5.0136676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 05/26/2023] [Indexed: 10/22/2023]
Abstract
We have developed a confocal laser microscope operating in the mid-infrared range for the study of light-sensitive proteins, such as rhodopsins. The microscope features a co-aligned infrared and visible illumination path for the selective excitation and probing of proteins located in the IR focus only. An external-cavity tunable quantum cascade laser provides a wavelength tuning range (5.80-6.35 µm or 1570-1724 cm-1) suitable for studying protein conformational changes as a function of time delay after visible light excitation with a pulsed LED. Using cryogen-free detectors, the relative changes in the infrared absorption of rhodopsin thin films around 10-4 have been observed with a time resolution down to 30 ms. The measured full-width at half maximum of the Airy disk at λ = 6.08 µm in transmission mode with a confocal arrangement of apertures is 6.6 µm or 1.1λ. Dark-adapted sample replacement at the beginning of each photocycle is then enabled by exchanging the illuminated thin-film location with the microscope mapping stage synchronized to data acquisition and LED excitation and by averaging hundreds of time traces acquired in different nearby locations within a homogeneous film area. We demonstrate that this instrument provides crucial advantages for time-resolved IR studies of rhodopsin thin films with a slow photocycle. Time-resolved studies of inhomogeneous samples may also be possible with the presented instrument.
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Affiliation(s)
- Maria Eleonora Temperini
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, Rome 00185, Italy
- Center for Life Nano & Neuro Science CL2NS, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome 00161, Italy
| | - Raffaella Polito
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, Rome 00185, Italy
| | - Antonia Intze
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, Rome 00185, Italy
- Center for Life Nano & Neuro Science CL2NS, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome 00161, Italy
| | - Raymond Gillibert
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, Rome 00185, Italy
| | - Fritz Berkmann
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, Rome 00185, Italy
| | - Leonetta Baldassarre
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, Rome 00185, Italy
| | - Valeria Giliberti
- Center for Life Nano & Neuro Science CL2NS, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome 00161, Italy
| | - Michele Ortolani
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, Rome 00185, Italy
- Center for Life Nano & Neuro Science CL2NS, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome 00161, Italy
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2
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Malerba M, Sotgiu S, Schirato A, Baldassarre L, Gillibert R, Giliberti V, Jeannin M, Manceau JM, Li L, Davies AG, Linfield EH, Alabastri A, Ortolani M, Colombelli R. Detection of Strong Light-Matter Interaction in a Single Nanocavity with a Thermal Transducer. ACS Nano 2022; 16:20141-20150. [PMID: 36399696 DOI: 10.1021/acsnano.2c04452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The concept of strong light-matter coupling has been demonstrated in semiconductor structures, and it is poised to revolutionize the design and implementation of components, including solid state lasers and detectors. We demonstrate an original nanospectroscopy technique that permits the study of the light-matter interaction in single subwavelength-sized nanocavities where far-field spectroscopy is not possible using conventional techniques. We inserted a thin (∼150 nm) polymer layer with negligible absorption in the mid-infrared range (5 μm < λ < 12 μm) inside a metal-insulator-metal resonant cavity, where a photonic mode and the intersubband transition of a semiconductor quantum well are strongly coupled. The intersubband transition peaks at λ = 8.3 μm, and the nanocavity is overall 270 nm thick. Acting as a nonperturbative transducer, the polymer layer introduces only a limited alteration of the optical response while allowing to reveal the optical power absorbed inside the concealed cavity. Spectroscopy of the cavity losses is enabled by the polymer thermal expansion due to heat dissipation in the active part of the cavity, and performed using atomic force microscopy (AFM). This innovative approach allows the typical anticrossing characteristic of the polaritonic dispersion to be identified in the cavity loss spectra at the single nanoresonator level. Results also suggest that near-field coupling of the external drive field to the top metal patch mediated by a metal-coated AFM probe tip is possible, and it enables the near-field mapping of the cavity mode symmetry including in the presence of a strong light-matter interaction.
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Affiliation(s)
- Mario Malerba
- Centre de Nanosciences et de Nanotechnologies (C2N), CNRS UMR 9001, Université Paris-Saclay, 10 Boulevard Thomas Gobert, 91120Palaiseau, France
| | - Simone Sotgiu
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185Rome, Italy
| | - Andrea Schirato
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133Milan, Italy
- Istituto Italiano di Tecnologia, via Morego 30, 16163Genoa, Italy
| | - Leonetta Baldassarre
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185Rome, Italy
| | - Raymond Gillibert
- Center for Life NanoScience, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161Rome, Italy
| | - Valeria Giliberti
- Center for Life NanoScience, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161Rome, Italy
| | - Mathieu Jeannin
- Centre de Nanosciences et de Nanotechnologies (C2N), CNRS UMR 9001, Université Paris-Saclay, 10 Boulevard Thomas Gobert, 91120Palaiseau, France
| | - Jean-Michel Manceau
- Centre de Nanosciences et de Nanotechnologies (C2N), CNRS UMR 9001, Université Paris-Saclay, 10 Boulevard Thomas Gobert, 91120Palaiseau, France
| | - Lianhe Li
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, LS29JTLeeds, United Kingdom
| | - Alexander Giles Davies
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, LS29JTLeeds, United Kingdom
| | - Edmund H Linfield
- School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, LS29JTLeeds, United Kingdom
| | - Alessandro Alabastri
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, Texas77005, United States
| | - Michele Ortolani
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185Rome, Italy
- Center for Life NanoScience, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161Rome, Italy
| | - Raffaele Colombelli
- Centre de Nanosciences et de Nanotechnologies (C2N), CNRS UMR 9001, Université Paris-Saclay, 10 Boulevard Thomas Gobert, 91120Palaiseau, France
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3
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Temperini ME, Di Giacinto F, Romanò S, Di Santo R, Augello A, Polito R, Baldassarre L, Giliberti V, Papi M, Basile U, Niccolini B, Krasnowska EK, Serafino A, De Spirito M, Di Gaspare A, Ortolani M, Ciasca G. Antenna-enhanced mid-infrared detection of extracellular vesicles derived from human cancer cell cultures. J Nanobiotechnology 2022; 20:530. [PMID: 36514065 PMCID: PMC9746222 DOI: 10.1186/s12951-022-01693-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 10/30/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Extracellular Vesicles (EVs) are sub-micrometer lipid-bound particles released by most cell types. They are considered a promising source of cancer biomarkers for liquid biopsy and personalized medicine due to their specific molecular cargo, which provides biochemical information on the state of parent cells. Despite this potential, EVs translation process in the diagnostic practice is still at its birth, and the development of novel medical devices for their detection and characterization is highly required. RESULTS In this study, we demonstrate mid-infrared plasmonic nanoantenna arrays designed to detect, in the liquid and dry phase, the specific vibrational absorption signal of EVs simultaneously with the unspecific refractive index sensing signal. For this purpose, EVs are immobilized on the gold nanoantenna surface by immunocapture, allowing us to select specific EV sub-populations and get rid of contaminants. A wet sample-handling technique relying on hydrophobicity contrast enables effortless reflectance measurements with a Fourier-transform infrared (FTIR) spectro-microscope in the wavelength range between 10 and 3 µm. In a proof-of-principle experiment carried out on EVs released from human colorectal adenocarcinoma (CRC) cells, the protein absorption bands (amide-I and amide-II between 5.9 and 6.4 µm) increase sharply within minutes when the EV solution is introduced in the fluidic chamber, indicating sensitivity to the EV proteins. A refractive index sensing curve is simultaneously provided by our sensor in the form of the redshift of a sharp spectral edge at wavelengths around 5 µm, where no vibrational absorption of organic molecules takes place: this permits to extract of the dynamics of EV capture by antibodies from the overall molecular layer deposition dynamics, which is typically measured by commercial surface plasmon resonance sensors. Additionally, the described metasurface is exploited to compare the spectral response of EVs derived from cancer cells with increasing invasiveness and metastatic potential, suggesting that the average secondary structure content in EVs can be correlated with cell malignancy. CONCLUSIONS Thanks to the high protein sensitivity and the possibility to work with small sample volumes-two key features for ultrasensitive detection of extracellular vesicles- our lab-on-chip can positively impact the development of novel laboratory medicine methods for the molecular characterization of EVs.
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Affiliation(s)
- Maria Eleonora Temperini
- grid.7841.aDepartment of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Rome, Italy ,grid.25786.3e0000 0004 1764 2907Center for Life Neuro and Nano Sciences IIT@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | - Flavio Di Giacinto
- grid.414603.4Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, Rome, Italy ,grid.8142.f0000 0001 0941 3192Dipartimento di Neuroscienze, Sezione di Fisica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Sabrina Romanò
- grid.414603.4Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, Rome, Italy ,grid.8142.f0000 0001 0941 3192Dipartimento di Neuroscienze, Sezione di Fisica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Riccardo Di Santo
- grid.414603.4Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, Rome, Italy
| | - Alberto Augello
- grid.414603.4Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, Rome, Italy
| | - Raffaella Polito
- grid.7841.aDepartment of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Rome, Italy
| | - Leonetta Baldassarre
- grid.7841.aDepartment of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Rome, Italy
| | - Valeria Giliberti
- grid.25786.3e0000 0004 1764 2907Center for Life Neuro and Nano Sciences IIT@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | - Massimiliano Papi
- grid.414603.4Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, Rome, Italy ,grid.8142.f0000 0001 0941 3192Dipartimento di Neuroscienze, Sezione di Fisica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Umberto Basile
- grid.414603.4Dipartimento di Scienze di Laboratorio e Infettivologiche, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Benedetta Niccolini
- grid.8142.f0000 0001 0941 3192Dipartimento di Neuroscienze, Sezione di Fisica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ewa K. Krasnowska
- grid.5326.20000 0001 1940 4177Institute of Translational Pharmacology, National Research Council of Italy, Rome, Italy
| | - Annalucia Serafino
- grid.5326.20000 0001 1940 4177Institute of Translational Pharmacology, National Research Council of Italy, Rome, Italy
| | - Marco De Spirito
- grid.414603.4Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, Rome, Italy ,grid.8142.f0000 0001 0941 3192Dipartimento di Neuroscienze, Sezione di Fisica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Alessandra Di Gaspare
- grid.414603.4Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, Rome, Italy ,grid.509494.5NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Michele Ortolani
- grid.7841.aDepartment of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Rome, Italy ,grid.25786.3e0000 0004 1764 2907Center for Life Neuro and Nano Sciences IIT@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | - Gabriele Ciasca
- grid.414603.4Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, Rome, Italy ,grid.8142.f0000 0001 0941 3192Dipartimento di Neuroscienze, Sezione di Fisica, Università Cattolica del Sacro Cuore, Rome, Italy
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Tanga AA, Giliberti V, Vitucci F, Vitulano D, Bruni V, Rossetti A, Messina GC, Daniele M, Ruocco G, Ortolani M. Terahertz scattering microscopy for dermatology diagnostics. J Phys Photonics 2021. [DOI: 10.1088/2515-7647/abfecb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
We explore the possibility of detecting anomalous structures buried under the skin surface by studying the deviations from the ideal Airy pattern of the point-spread function (PSF) of a terahertz microscope that includes the skin as one of the reflecting surfaces of the optical system. Using a custom terahertz microscope with a monochromatic point source emitting at 0.611 THz, we record the PSF images with a microbolometer camera. Skin simulants based on collagen gel, with and without artificial buried structures, have been analyzed. The geometrical features characterizing the PSF deformations have been extracted automatically from the PSF images. A machine learning algorithm applied to these geometrical features produces a reliable classification of targets with or without buried structures with error below 5%. It can even classify targets with anisotropic buried structures according to their different orientation.
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Occhicone A, Pea M, Polito R, Giliberti V, Sinibaldi A, Mattioli F, Cibella S, Notargiacomo A, Nucara A, Biagioni P, Michelotti F, Ortolani M, Baldassarre L. Spectral Characterization of Mid-Infrared Bloch Surface Waves Excited on a Truncated 1D Photonic Crystal. ACS Photonics 2021; 8:350-359. [PMID: 33585665 PMCID: PMC7871362 DOI: 10.1021/acsphotonics.0c01657] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Indexed: 06/01/2023]
Abstract
The many fundamental roto-vibrational resonances of chemical compounds result in strong absorption lines in the mid-infrared region (λ ∼ 2-20 μm). For this reason, mid-infrared spectroscopy plays a key role in label-free sensing, in particular, for chemical recognition, but often lacks the required sensitivity to probe small numbers of molecules. In this work, we propose a vibrational sensing scheme based on Bloch surface waves (BSWs) on 1D photonic crystals to increase the sensitivity of mid-infrared sensors. We report on the design and deposition of CaF2/ZnS 1D photonic crystals. Moreover, we theoretically and experimentally demonstrate the possibility to sustain narrow σ-polarized BSW modes together with broader π-polarized modes in the range of 3-8 μm by means of a customized Fourier transform infrared spectroscopy setup. The multilayer stacks are deposited directly on CaF2 prisms, reducing the number of unnecessary interfaces when exciting in the Kretschmann-Raether configuration. Finally, we compare the performance of mid-IR sensors based on surface plasmon polaritons with the BSW-based sensor. The figures of merit found for BSWs in terms of confinement of the electromagnetic field and propagation length puts them as forefrontrunners for label-free and polarization-dependent sensing devices.
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Affiliation(s)
- Agostino Occhicone
- SAPIENZA
University of Rome, Department of Basic
and Applied Sciences for Engineering, Via A. Scarpa, 16, 00161 Roma, Italy
| | - Marialilia Pea
- CNR
Consiglio Nazionale delle Ricerche, Institute for Photonics and Nanotechnologies, Via Cineto Romano, 42, 00156 Roma, Italy
| | - Raffaella Polito
- SAPIENZA
University of Rome, Department of Physics, Piazzale Aldo Moro, 5, 00185 Roma, Italy
| | - Valeria Giliberti
- Istituto
Italiano di Tecnologia, Center for Life
Nanosciences, Viale Regina
Elena, 291, 00161 Roma, Italy
| | - Alberto Sinibaldi
- SAPIENZA
University of Rome, Department of Basic
and Applied Sciences for Engineering, Via A. Scarpa, 16, 00161 Roma, Italy
| | - Francesco Mattioli
- CNR
Consiglio Nazionale delle Ricerche, Institute for Photonics and Nanotechnologies, Via Cineto Romano, 42, 00156 Roma, Italy
| | - Sara Cibella
- CNR
Consiglio Nazionale delle Ricerche, Institute for Photonics and Nanotechnologies, Via Cineto Romano, 42, 00156 Roma, Italy
| | - Andrea Notargiacomo
- CNR
Consiglio Nazionale delle Ricerche, Institute for Photonics and Nanotechnologies, Via Cineto Romano, 42, 00156 Roma, Italy
| | - Alessandro Nucara
- SAPIENZA
University of Rome, Department of Physics, Piazzale Aldo Moro, 5, 00185 Roma, Italy
| | - Paolo Biagioni
- Politecnico
di Milano, Department of Physics, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy
| | - Francesco Michelotti
- SAPIENZA
University of Rome, Department of Basic
and Applied Sciences for Engineering, Via A. Scarpa, 16, 00161 Roma, Italy
| | - Michele Ortolani
- SAPIENZA
University of Rome, Department of Physics, Piazzale Aldo Moro, 5, 00185 Roma, Italy
- Istituto
Italiano di Tecnologia, Center for Life
Nanosciences, Viale Regina
Elena, 291, 00161 Roma, Italy
| | - Leonetta Baldassarre
- SAPIENZA
University of Rome, Department of Physics, Piazzale Aldo Moro, 5, 00185 Roma, Italy
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6
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Temperini ME, Polito R, Intze A, Schade U, Puskar L, Ritter E, Baldassarre L, Ortolani M, Giliberti V. Infrared nanospectroscopy study of the light-induced conformational changes of Channelrhodopsin. EPJ Web Conf 2021. [DOI: 10.1051/epjconf/202125513001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The channelrhodopsin-ChR2 is a light-sensitive transmembrane protein that acts as a selective ion channel between the intra- and the extra-cellular environments. In the last decade, ChR2 has proven to be essential for optogenetics, because, if expressed in mammalian neural cells, it enables the control of neuronal activity in response to visible light. Mid-infrared difference spectroscopy can probe the functional conformational changes of light-sensitive proteins, however intrinsic limitations of standard IR spectroscopy in terms of diffraction, and therefore number of probed proteins, require that the mid-IR experiments be performed on huge numbers of lipid membrane patches with overexpressed proteins. In this work, we apply for the first time IR difference nanospectroscopy, based on the use of mid-IR lasers and an atomic force microscope (AFM), to single membrane patches containing ChR2, obtaining relevant spectroscopy results for optogenetic applications and, more generally, for future experimental studies of light-sensitive proteins at the nanoscale.
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Costanzo G, Šponer JE, Šponer J, Cirigliano A, Benedetti P, Giliberti V, Polito R, Di Mauro E. Front Cover: Sustainability and Chaos in the Abiotic Polymerization of 3′,5′ Cyclic Guanosine Monophosphate: The Role of Aggregation (ChemSystemsChem 1/2021). ChemSystemsChem 2021. [DOI: 10.1002/syst.202000057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Giovanna Costanzo
- Institute of Molecular Biology and Pathology, CNR Piazzale A. Moro 5 00185 Rome Italy
| | - Judit E. Šponer
- Institute of Biophysics of the Czech Academy of Sciences Královopolská 135 61265 Brno Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences Královopolská 135 61265 Brno Czech Republic
| | - Angela Cirigliano
- Institute of Molecular Biology and Pathology, CNR Piazzale A. Moro 5 00185 Rome Italy
| | - Piero Benedetti
- Department of Biology University of Padua (Italy) On leave at: Centro Linceo “Beniamino Segre” Accademia Nazionale dei Lincei via della Lungara 10 00165 Rome Italy
| | - Valeria Giliberti
- Center for Life NanoSciences Istituto Italiano di Tecnologia (IIT) Viale Regina Elena 291 00166 Rome Italy
| | - Raffaella Polito
- Department of Physics Sapienza University of Rome Piazzale Aldo Moro 2 00185 Rome Italy
| | - Ernesto Di Mauro
- Institute of Molecular Biology and Pathology, CNR Piazzale A. Moro 5 00185 Rome Italy
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8
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Costanzo G, Šponer JE, Šponer J, Cirigliano A, Benedetti P, Giliberti V, Polito R, Di Mauro E. Sustainability and Chaos in the Abiotic Polymerization of 3’,5’ Cyclic Guanosine Monophosphate: The Role of Aggregation. ChemSystemsChem 2020. [DOI: 10.1002/syst.202000056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Giovanna Costanzo
- Institute of Molecular Biology and Pathology, CNR Piazzale A. Moro 5 00185 Rome Italy
| | - Judit E. Šponer
- Institute of Biophysics of the Czech Academy of Sciences Královopolská 135 61265 Brno Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences Královopolská 135 61265 Brno Czech Republic
| | - Angela Cirigliano
- Institute of Molecular Biology and Pathology, CNR Piazzale A. Moro 5 00185 Rome Italy
| | - Piero Benedetti
- Department of Biology University of Padua (Italy) On leave at: Centro Linceo “Beniamino Segre” Accademia Nazionale dei Lincei via della Lungara 10 00165 Rome Italy
| | - Valeria Giliberti
- Center for Life NanoSciences Istituto Italiano di Tecnologia (IIT) Viale Regina Elena 291 00166 Rome Italy
| | - Raffaella Polito
- Department of Physics Sapienza University of Rome Piazzale Aldo Moro 2 00185 Rome Italy
| | - Ernesto Di Mauro
- Institute of Molecular Biology and Pathology, CNR Piazzale A. Moro 5 00185 Rome Italy
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9
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Gallacher K, Millar RW, Paul DJ, Frigerio J, Ballabio A, Isella G, Rusconi F, Biagioni P, Giliberti V, Sorgi A, Baldassarre L, Ortolani M. Characterization of integrated waveguides by atomic-force-microscopy-assisted mid-infrared imaging and spectroscopy. Opt Express 2020; 28:22186-22199. [PMID: 32752485 DOI: 10.1364/oe.393748] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/15/2020] [Indexed: 06/11/2023]
Abstract
A novel spectroscopy technique to enable the rapid characterization of discrete mid-infrared integrated photonic waveguides is demonstrated. The technique utilizes lithography patterned polymer blocks that absorb light strongly within the molecular fingerprint region. These act as integrated waveguide detectors when combined with an atomic force microscope that measures the photothermal expansion when infrared light is guided to the block. As a proof of concept, the technique is used to experimentally characterize propagation loss and grating coupler response of Ge-on-Si waveguides at wavelengths from 6 to 10 µm. In addition, when the microscope is operated in scanning mode at fixed wavelength, the guided mode exiting the output facet is imaged with a lateral resolution better than 500 nm i.e. below the diffraction limit. The characterization technique can be applied to any mid-infrared waveguide platform and can provide non-destructive in-situ testing of discrete waveguide components.
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10
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Giliberti V, Polito R, Ritter E, Broser M, Hegemann P, Puskar L, Schade U, Zanetti-Polzi L, Daidone I, Corni S, Rusconi F, Biagioni P, Baldassarre L, Ortolani M. Tip-Enhanced Infrared Difference-Nanospectroscopy of the Proton Pump Activity of Bacteriorhodopsin in Single Purple Membrane Patches. Nano Lett 2019; 19:3104-3114. [PMID: 30950626 PMCID: PMC6745627 DOI: 10.1021/acs.nanolett.9b00512] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/02/2019] [Indexed: 05/21/2023]
Abstract
Photosensitive proteins embedded in the cell membrane (about 5 nm thickness) act as photoactivated proton pumps, ion gates, enzymes, or more generally, as initiators of stimuli for the cell activity. They are composed of a protein backbone and a covalently bound cofactor (e.g. the retinal chromophore in bacteriorhodopsin (BR), channelrhodopsin, and other opsins). The light-induced conformational changes of both the cofactor and the protein are at the basis of the physiological functions of photosensitive proteins. Despite the dramatic development of microscopy techniques, investigating conformational changes of proteins at the membrane monolayer level is still a big challenge. Techniques based on atomic force microscopy (AFM) can detect electric currents through protein monolayers and even molecular binding forces in single-protein molecules but not the conformational changes. For the latter, Fourier-transform infrared spectroscopy (FTIR) using difference-spectroscopy mode is typically employed, but it is performed on macroscopic liquid suspensions or thick films containing large amounts of purified photosensitive proteins. In this work, we develop AFM-assisted, tip-enhanced infrared difference-nanospectroscopy to investigate light-induced conformational changes of the bacteriorhodopsin mutant D96N in single submicrometric native purple membrane patches. We obtain a significant improvement compared with the signal-to-noise ratio of standard IR nanospectroscopy techniques by exploiting the field enhancement in the plasmonic nanogap that forms between a gold-coated AFM probe tip and an ultraflat gold surface, as further supported by electromagnetic and thermal simulations. IR difference-spectra in the 1450-1800 cm-1 range are recorded from individual patches as thin as 10 nm, with a diameter of less than 500 nm, well beyond the diffraction limit for FTIR microspectroscopy. We find clear spectroscopic evidence of a branching of the photocycle for BR molecules in direct contact with the gold surfaces, with equal amounts of proteins either following the standard proton-pump photocycle or being trapped in an intermediate state not directly contributing to light-induced proton transport. Our results are particularly relevant for BR-based optoelectronic and energy-harvesting devices, where BR molecular monolayers are put in contact with metal surfaces, and, more generally, for AFM-based IR spectroscopy studies of conformational changes of proteins embedded in intrinsically heterogeneous native cell membranes.
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Affiliation(s)
- Valeria Giliberti
- Istituto
Italiano di Tecnologia, Center for Life NanoScience, Viale Regina Elena 291, I-00161 Roma, Italy
- E-mail:
| | - Raffaella Polito
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, I-00185 Roma, Italy
| | - Eglof Ritter
- Humboldt-Universität
zu Berlin, Institut für
Biologie, Invalidenstraße
42, D-10115 Berlin, Germany
| | - Matthias Broser
- Humboldt-Universität
zu Berlin, Institut für
Biologie, Invalidenstraße
42, D-10115 Berlin, Germany
| | - Peter Hegemann
- Humboldt-Universität
zu Berlin, Institut für
Biologie, Invalidenstraße
42, D-10115 Berlin, Germany
| | - Ljiljana Puskar
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Ulrich Schade
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Laura Zanetti-Polzi
- Department
of Physical and Chemical Sciences, University
of L’Aquila, Via Vetoio, I-67010 L’Aquila, Italy
| | - Isabella Daidone
- Department
of Physical and Chemical Sciences, University
of L’Aquila, Via Vetoio, I-67010 L’Aquila, Italy
| | - Stefano Corni
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
- CNR
Institute
of Nanoscience, Via Campi
213/A, I-41125 Modena, Italy
| | - Francesco Rusconi
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Paolo Biagioni
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Leonetta Baldassarre
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, I-00185 Roma, Italy
| | - Michele Ortolani
- Istituto
Italiano di Tecnologia, Center for Life NanoScience, Viale Regina Elena 291, I-00161 Roma, Italy
- Department
of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, I-00185 Roma, Italy
- E-mail:
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Giliberti V, Badioli M, Nucara A, Calvani P, Ritter E, Puskar L, Aziz EF, Hegemann P, Schade U, Ortolani M, Baldassarre L. Heterogeneity of the Transmembrane Protein Conformation in Purple Membranes Identified by Infrared Nanospectroscopy. Small 2017; 13:1701181. [PMID: 28960799 DOI: 10.1002/smll.201701181] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 08/02/2017] [Indexed: 06/07/2023]
Abstract
Cell membranes are intrinsically heterogeneous, as the local protein and lipid distribution is critical to physiological processes. Even in template systems embedding a single protein type, like purple membranes, there can be a different local response to external stimuli or environmental factors, resulting in heterogeneous conformational changes. Despite the dramatic advances of microspectroscopy techniques, the identification of the conformation heterogeneity is still a challenging task. Tip-enhanced infrared nanospectroscopy is here used to identify conformational changes connected to the hydration state of the transmembrane proteins contained in a 50 nm diameter cell membrane area, without the need for fluorescent labels. In dried purple membrane monolayers, areas with fully hydrated proteins are found among large numbers of molecules with randomly distributed hydration states. Infrared nanospectroscopy results are compared to the spectra obtained with diffraction-limited infrared techniques based on the use of synchrotron radiation, in which the diffraction limit still prevents the observation of nanoscale heterogeneity.
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Affiliation(s)
- Valeria Giliberti
- Istituto Italiano di Tecnologia, Center for Life NanoScience, Viale Regina Elena 291, I-00161, Roma, Italy
| | - Michela Badioli
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, I-00185, Roma, Italy
| | - Alessandro Nucara
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, I-00185, Roma, Italy
| | - Paolo Calvani
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, I-00185, Roma, Italy
| | - Eglof Ritter
- Humboldt-Universität zu Berlin, Institut für Biologie, Invalidenstraße 42, D-10115, Berlin, Germany
| | - Ljiljana Puskar
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489, Berlin, Germany
| | - Emad Flear Aziz
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489, Berlin, Germany
| | - Peter Hegemann
- Humboldt-Universität zu Berlin, Institut für Biologie, Invalidenstraße 42, D-10115, Berlin, Germany
| | - Ulrich Schade
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489, Berlin, Germany
| | - Michele Ortolani
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, I-00185, Roma, Italy
| | - Leonetta Baldassarre
- Istituto Italiano di Tecnologia, Center for Life NanoScience, Viale Regina Elena 291, I-00161, Roma, Italy
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, I-00185, Roma, Italy
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Giliberti V, Baldassarre L, Rosa A, de Turris V, Ortolani M, Calvani P, Nucara A. Protein clustering in chemically stressed HeLa cells studied by infrared nanospectroscopy. Nanoscale 2016; 8:17560-17567. [PMID: 27714081 DOI: 10.1039/c6nr05783g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Photo-Thermal Induced Resonance (PTIR) nanospectroscopy, tuned towards amide-I absorption, was used to study the distribution of proteic material in 34 different HeLa cells, of which 18 were chemically stressed by oxidative stress with Na3AsO3. The cell nucleus was found to provide a weaker amide-I signal than the surrounding cytoplasm, while the strongest PTIR signal comes from the perinuclear region. AFM topography shows that the cells exposed to oxidative stress undergo a volume reduction with respect to the control cells, through an accumulation of the proteic material around and above the nucleus. This is confirmed by the PTIR maps of the cytoplasm, where the pixels providing a high amide-I signal were identified with a space resolution of ∼300 × 300 nm. By analyzing their distribution with two different statistical procedures we found that the probability to find protein clusters smaller than 0.6 μm in the cytoplasm of stressed HeLa cells is higher by 35% than in the control cells. These results indicate that it is possible to study proteic clustering within single cells by label-free optical nanospectroscopy.
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Affiliation(s)
- V Giliberti
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, V.le Regina Elena 291, 00161 Roma, Italy
| | - L Baldassarre
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, V.le Regina Elena 291, 00161 Roma, Italy and Dipartimento di Fisica, Università di Roma La Sapienza, P.le Aldo Moro 5, 00185 Roma, Italy.
| | - A Rosa
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, V.le Regina Elena 291, 00161 Roma, Italy and Dipartimento di Biologia e Biotecnologie Charles Darwin, Universita di Roma La Sapienza, P.le Aldo Moro 5, 00185 Roma, Italy
| | - V de Turris
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, V.le Regina Elena 291, 00161 Roma, Italy
| | - M Ortolani
- Dipartimento di Fisica, Università di Roma La Sapienza, P.le Aldo Moro 5, 00185 Roma, Italy.
| | - P Calvani
- Dipartimento di Fisica, Università di Roma La Sapienza, P.le Aldo Moro 5, 00185 Roma, Italy.
| | - A Nucara
- Dipartimento di Fisica, Università di Roma La Sapienza, P.le Aldo Moro 5, 00185 Roma, Italy.
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13
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Baldassarre L, Giliberti V, Rosa A, Ortolani M, Bonamore A, Baiocco P, Kjoller K, Calvani P, Nucara A. Mapping the amide I absorption in single bacteria and mammalian cells with resonant infrared nanospectroscopy. Nanotechnology 2016; 27:075101. [PMID: 26778320 DOI: 10.1088/0957-4484/27/7/075101] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Infrared (IR) nanospectroscopy performed in conjunction with atomic force microscopy (AFM) is a novel, label-free spectroscopic technique that meets the increasing request for nano-imaging tools with chemical specificity in the field of life sciences. In the novel resonant version of AFM-IR, a mid-IR wavelength-tunable quantum cascade laser illuminates the sample below an AFM tip working in contact mode, and the repetition rate of the mid-IR pulses matches the cantilever mechanical resonance frequency. The AFM-IR signal is the amplitude of the cantilever oscillations driven by the thermal expansion of the sample after absorption of mid-IR radiation. Using purposely nanofabricated polymer samples, here we demonstrate that the AFM-IR signal increases linearly with the sample thickness t for t > 50 nm, as expected from the thermal expansion model of the sample volume below the AFM tip. We then show the capability of the apparatus to derive information on the protein distribution in single cells through mapping of the AFM-IR signal related to the amide-I mid-IR absorption band at 1660 cm(-1). In Escherichia Coli bacteria we see how the topography changes, observed when the cell hosts a protein over-expression plasmid, are correlated with the amide I signal intensity. In human HeLa cells we obtain evidence that the protein distribution in the cytoplasm and in the nucleus is uneven, with a lateral resolution better than 100 nm.
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Affiliation(s)
- L Baldassarre
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, V.le Regina Elena 291, Rome I-00185, Italy
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14
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Nucara A, Maselli P, Giliberti V, Carbonaro M. Epicatechin-induced conformational changes in β-lactoglobulin B monitored by FT-IR spectroscopy. Springerplus 2013; 2:661. [PMID: 24353978 PMCID: PMC3866372 DOI: 10.1186/2193-1801-2-661] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 11/12/2013] [Indexed: 12/31/2022]
Abstract
ABSTRACT The interaction between whey carrier protein β-lactoglobulin B and (-)-epicatechin, a major dietary flavonoid with a wide range of health-promoting biological activities, was investigated by Fourier transform infrared spectroscopy in physiological conditions. Amide I spectra of epicatechin - β-lactoglobulin complexes, in D2O buffer solutions, pD= 6.8, at molar ratios from 0.5:1 to 15:1, were measured by using a cell device specifically created. Changes in secondary structure elements at increasing epicatechin concentrations were quantified. Two different trends were observed for the intensities of β-sheet, random coil, and side chain contributions. At molar ratios ≤2 the β-exposed strand contributions (1625 cm(-1)) increased at the expence of the β-antiparallel sheet band (1637 cm(-1)). At molar ratios >2 the intensities of both β structures slightly decreased. The same behaviour was observed for the side chain contributions (band around 1610 ÷ 1620 cm(-1)). In addition, a conformational transition to a slightly opened structure, followed by aggregate formation at the highest molar ratios, were revealed. The results suggest that binding of epicatechin to β-lactoglobulin in physiological conditions occurs at the surface of the protein molecule, resulting in protein dissociation at molar ratios ≤2 with minor changes in secondary structure. This finding provides further evidence for the possibility of successful use of the protein as a carrier of flavonoids, epicatechin included.
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Affiliation(s)
- Alessandro Nucara
- Consiglio per la Ricerca e la sperimentazione in Agricoltura - Centro di Ricerca per gli Alimenti e la Nutrizione, Via Ardeatina 546, 00178 Rome, Italy
| | - Paola Maselli
- Consiglio per la Ricerca e la sperimentazione in Agricoltura - Centro di Ricerca per gli Alimenti e la Nutrizione, Via Ardeatina 546, 00178 Rome, Italy
| | - Valeria Giliberti
- CNR-Istituto di Fotonica e Nanotecnologie, Via Cineto Romano 42, 00156 Rome, Italy
| | - Marina Carbonaro
- Consiglio per la Ricerca e la sperimentazione in Agricoltura - Centro di Ricerca per gli Alimenti e la Nutrizione, Via Ardeatina 546, 00178 Rome, Italy
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15
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Di Pietro P, Ortolani M, Limaj O, Di Gaspare A, Giliberti V, Giorgianni F, Brahlek M, Bansal N, Koirala N, Oh S, Calvani P, Lupi S. Observation of Dirac plasmons in a topological insulator. Nat Nanotechnol 2013; 8:556-60. [PMID: 23872838 DOI: 10.1038/nnano.2013.134] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 06/12/2013] [Indexed: 05/26/2023]
Abstract
Plasmons are quantized collective oscillations of electrons and have been observed in metals and doped semiconductors. The plasmons of ordinary, massive electrons have been the basic ingredients of research in plasmonics and in optical metamaterials for a long time. However, plasmons of massless Dirac electrons have only recently been observed in graphene, a purely two-dimensional electron system. Their properties are promising for novel tunable plasmonic metamaterials in the terahertz and mid-infrared frequency range. Dirac fermions also occur in the two-dimensional electron gas that forms at the surface of topological insulators as a result of the strong spin-orbit interaction existing in the insulating bulk phase. One may therefore look for their collective excitations using infrared spectroscopy. Here we report the first experimental evidence of plasmonic excitations in a topological insulator (Bi2Se3). The material was prepared in thin micro-ribbon arrays of different widths W and periods 2W to select suitable values of the plasmon wavevector k. The linewidth of the plasmon was found to remain nearly constant at temperatures between 6 K and 300 K, as expected when exciting topological carriers. Moreover, by changing W and measuring the plasmon frequency in the terahertz range versus k we show, without using any fitting parameter, that the dispersion curve agrees quantitatively with that predicted for Dirac plasmons.
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Affiliation(s)
- P Di Pietro
- CNR-SPIN, Corso F. Perrone, 16152 Genoa, Italy
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16
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Baldassarre L, Ortolani M, Nucara A, Maselli P, Di Gaspare A, Giliberti V, Calvani P. Intrinsic linewidth of the plasmonic resonance in a micrometric metal mesh. Opt Express 2013; 21:15401-15408. [PMID: 23842327 DOI: 10.1364/oe.21.015401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The intrinsic linewidth and angular dispersion of Surface Plasmon Polariton resonance of a micrometric metal mesh have been measured with a collimated mid-infrared beam, provided by an External Cavity tunable Quantum Cascade Laser. We show that the use of a collimated beam yields an observed resonance linewidth γ = 12 cm(-1) at the resonance frequency ν0 = 1658 cm(-1), better by an order of magnitude than with a non-collimated beam. The extremely narrow plasmon resonance attained by our mesh is then exploited to reconstruct, by varying the QCL angle of incidence θ, the angular intensity distribution f(θ) of a globar at the focal plane of a conventional imaging setup. We thus show that f(θ) is better reproduced by a Gaussian distribution than by a uniform one, in agreement with ray-tracing simulation.
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Affiliation(s)
- L Baldassarre
- Center for Life NanoScience@Sapienza, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00185 Rome, Italy
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