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Gongalsky MB, Muftieva DA, Saarinen JKS, Isomaki A, Pervushin NV, Kopeina GS, Peltonen LJ, Strachan CJ, Zhivotovsky B, Santos HA, Osminkina LA. Nonresonant CARS Imaging of Porous and Solid Silicon Nanoparticles in Human Cells. ACS Biomater Sci Eng 2021; 8:4185-4195. [PMID: 34553922 DOI: 10.1021/acsbiomaterials.1c00771] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Coherent anti-Stokes Raman scattering (CARS), a nonlinear optical method for rapid visualization of biological objects, represents a progressive tool in biology and medicine to explore cells and tissue structures in living systems and biopsies. In this study, we report efficient nonresonant CARS imaging of silicon nanoparticles (SiNPs) in human cells as a proof of concept. As both bulk and porous silicon exhibit a high third-order nonlinear susceptibility, χ(3), which is responsible for the CARS intensity, it is possible to visualize the SiNPs without specific labels. Porous and solid SiNPs were obtained from layers of porous and nonporous silicon nanowires and mesoporous silicon. Electron microscopy and Raman spectroscopy showed that porous SiNPs consisted of ∼3 nm silicon nanocrystals (nc-Si) and pores, whereas solid nanoparticles comprised ∼30 nm nc-Si. All types of SiNPs were nontoxic at concentrations up to 500 μg/mL after 24 h of incubation with cells. We demonstrated that although nc-Si possesses a distinguished narrow Raman band of about 520 cm-1, it is possible to detect a high CARS signal from SiNPs in the epi-direction even in a nonresonant regime. 3D CARS images showed that all types of studied SiNPs were visualized as bright spots inside the cytoplasm of cells after 3-6 h of incubation because of the contrast provided by the high third-order nonlinear susceptibility of SiNPs, which is 1 × 104 to 1 × 105 times higher than that of water and typical biological media. Overall, CARS microscopy can provide localization of SiNPs within biological structures at the cellular level and can be a powerful tool for in vitro monitoring of silicon-based drug delivery systems or use SiNPs as labels to monitor various bioprocesses inside living cells.
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Affiliation(s)
- Maxim B Gongalsky
- Lomonosov Moscow State University, Faculty of Physics, Leninskie Gory 1, Moscow 119991, Russian Federation
| | - Daniela A Muftieva
- Lomonosov Moscow State University, Faculty of Physics, Leninskie Gory 1, Moscow 119991, Russian Federation
| | - Jukka K S Saarinen
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki FI-00014, Finland
| | - Antti Isomaki
- Biomedicum Imaging Unit, Faculty of Medicine, University of Helsinki, Haartmaninkatu 8 (PO Box 63), Helsinki 00014, Finland
| | - Nikolay V Pervushin
- Faculty of Fundamental Medicine, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russian Federation
| | - Gelina S Kopeina
- Faculty of Fundamental Medicine, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russian Federation
| | - Leena J Peltonen
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki FI-00014, Finland
| | - Clare J Strachan
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki FI-00014, Finland
| | - Boris Zhivotovsky
- Faculty of Fundamental Medicine, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russian Federation.,Institute of Environmental Medicine, Division of Toxicology, Karolinska Institutet, Box 210, Stockholm SE-171 77, Sweden
| | - Hélder A Santos
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki FI-00014, Finland.,Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki FI-00014, Finland
| | - Liubov A Osminkina
- Lomonosov Moscow State University, Faculty of Physics, Leninskie Gory 1, Moscow 119991, Russian Federation.,Institute for Biological Instrumentation of Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russian Federation
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Deckert V, Deckert-Gaudig T, Cialla-May D, Popp J, Zell R, Deinhard-Emmer S, Sokolov AV, Yi Z, Scully MO. Laser spectroscopic technique for direct identification of a single virus I: FASTER CARS. Proc Natl Acad Sci U S A 2020; 117:27820-4. [PMID: 33093197 DOI: 10.1073/pnas.2013169117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Surface features of a virus are very important in determining its virility. For example, the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to the ACE2 receptor site of the host cell with a much stronger affinity than did the original SARS virus. Thus, it is clearly important to understand the virion surface structure. To that end, the present paper combines the spatial resolution of atomic force microscopy and the spectral resolution of coherent Raman spectroscopy. This combination of tip-enhanced microscopy using femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering (FAST CARS) with enhanced resolution (FASTER CARS) allows us to map a single virus particle with nanometer resolution and chemical specificity. From the famous 1918 H1N1 influenza to the present COVID-19 pandemic, the need for improved viral detection techniques is all too apparent. The aim of the present paper is to show that identification of individual virus particles in clinical sample materials quickly and reliably is near at hand. First of all, our team has developed techniques for identification of virions based on a modular atomic force microscopy (AFM). Furthermore, femtosecond adaptive spectroscopic techniques with enhanced resolution via coherent anti-Stokes Raman scattering (FASTER CARS) using tip-enhanced techniques markedly improves the sensitivity [M. O. Scully, et al., Proc. Natl. Acad. Sci. U.S.A. 99, 10994–11001 (2002)].
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Geitner R, Legesse FB, Kuhl N, Bocklitz TW, Zechel S, Vitz J, Hager M, Schubert US, Dietzek B, Schmitt M, Popp J. Do You Get What You See? Understanding Molecular Self-Healing. Chemistry 2018; 24:2493-2502. [PMID: 29266504 DOI: 10.1002/chem.201705836] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Indexed: 11/11/2022]
Abstract
The self-healing ability of self-healing materials is often analyzed using morphologic microscopy images. Here it was possible to show that morphologic information alone is not sufficient to judge the status of a self-healing process and molecular information is required as well. When comparing molecular coherent anti-Stokes Raman scattering (CARS) and morphological laser reflection images during a standard scratch healing test of an intrinsic self-healing polymer network, it was found that the morphologic closing of the scratch and the molecular crosslinking of the material do not take place simultaneously. This important observation can be explained by the fact that the self-healing process of the thiol-ene based polymer network is limited by the mobility of alkene-containing compounds, which can only be monitored by molecular CARS microscopy and not by standard morphological imaging. Additionally, the recorded CARS images indicate a mechanochemical activation of the self-healing material by the scratching/damaging process, which leads to an enhanced self-healing behavior in the vicinity of the scratch.
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Affiliation(s)
- Robert Geitner
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Fisseha-Bekele Legesse
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Natascha Kuhl
- Institute for Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany.,Jena Center of Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - Thomas W Bocklitz
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany.,Leibniz Institute for Photonic Technology (IPHT) Jena, Albert-Einstein-Str. 9, 07745, Jena, Germany
| | - Stefan Zechel
- Institute for Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany.,Jena Center of Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - Jürgen Vitz
- Institute for Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany.,Jena Center of Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - Martin Hager
- Institute for Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany.,Jena Center of Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - Ulrich S Schubert
- Institute for Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany.,Jena Center of Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany
| | - Benjamin Dietzek
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany.,Jena Center of Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany.,Leibniz Institute for Photonic Technology (IPHT) Jena, Albert-Einstein-Str. 9, 07745, Jena, Germany
| | - Michael Schmitt
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Jürgen Popp
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany.,Jena Center of Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany.,Leibniz Institute for Photonic Technology (IPHT) Jena, Albert-Einstein-Str. 9, 07745, Jena, Germany
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Scherer S, Wollrab E, Codutti L, Carlomagno T, da Costa SG, Volkmer A, Bronja A, Schmitz OJ, Ott A. Chemical Analysis of a "Miller-Type" Complex Prebiotic Broth : Part II: Gas, Oil, Water and the Oil/Water-Interface. ORIGINS LIFE EVOL B 2016; 47:381-403. [PMID: 27896547 PMCID: PMC5705758 DOI: 10.1007/s11084-016-9528-8] [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] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/02/2016] [Indexed: 12/14/2022]
Abstract
We have analyzed the chemical variety obtained by Miller-Urey-type experiments using nuclear magnetic resonance (NMR) spectroscopy and coherent anti-Stokes Raman scattering (CARS) spectroscopy, gas chromatography followed by mass spectrometry (GC/MS) and two-dimensional gas chromatography followed by mass spectrometry (GCxGC/MS). In the course of a running Miller-Urey-type experiment, a hydrophobic organic layer emerged besides the hydrophilic aqueous phase and the gaseous phase that were initially present. The gas phase mainly consisted of aromatic compounds and molecules containing C≡C or C≡N triple bonds. The hydrophilic phase contained at least a few thousands of different molecules, primarily distributed in a range of 50 and 500 Da. The hydrophobic phase is characterized by carbon-rich, oil-like compounds and their amphiphilic derivatives containing oxygen with tensioactive properties. The presence of a wide range of oxidized molecules hints to the availability of oxygen radicals. We suggest that they intervene in the formation of alkylated polyethylene glycol (PEG) in the oil/water interface. CARS spectroscopy revealed distinct vibrational molecular signatures. In particular, characteristic spectral bands for cyanide compounds were observed if the broth was prepared with electric discharges in the gaseous phase. The characteristic spectral bands were absent if discharges were released onto the water surface. NMR spectroscopy on the same set of samples independently confirmed the observation. In addition, NMR spectroscopy revealed overall high chemical variability that suggests strong non-linearities due to interdependent, sequential reaction steps.
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Affiliation(s)
- Sabrina Scherer
- Biologische Experimentalphysik, Universität des Saarlandes, Campus, Geb. B2 1, 66123 Saarbrücken, Germany
| | - Eva Wollrab
- Biologische Experimentalphysik, Universität des Saarlandes, Campus, Geb. B2 1, 66123 Saarbrücken, Germany
- Present Address: Laboratory of Microbial Morphogenesis and Growth, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Luca Codutti
- Centre of Biomolecular Drug Research, Leibniz University, Schneiderberg 38, 30167 Hannover, Germany
| | - Teresa Carlomagno
- Centre of Biomolecular Drug Research, Leibniz University, Schneiderberg 38, 30167 Hannover, Germany
| | - Stefan Gomes da Costa
- Coherent Raman Scattering Microscopy and Single-Molecule Spectroscopy Group, 3. Institute of Physics, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Andreas Volkmer
- Coherent Raman Scattering Microscopy and Single-Molecule Spectroscopy Group, 3. Institute of Physics, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Amela Bronja
- Applied Analytical Chemistry, University of Duisburg-Essen, Campus Essen, S05 T01 B35, Universitaetsstr. 5, 45141 Essen, Germany
| | - Oliver J. Schmitz
- Applied Analytical Chemistry, University of Duisburg-Essen, Campus Essen, S05 T01 B35, Universitaetsstr. 5, 45141 Essen, Germany
| | - Albrecht Ott
- Biologische Experimentalphysik, Universität des Saarlandes, Campus, Geb. B2 1, 66123 Saarbrücken, Germany
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Tolstik E, Osminkina LA, Akimov D, Gongalsky MB, Kudryavtsev AA, Timoshenko VY, Heintzmann R, Sivakov V, Popp J. Linear and Non-Linear Optical Imaging of Cancer Cells with Silicon Nanoparticles. Int J Mol Sci 2016; 17:E1536. [PMID: 27626408 PMCID: PMC5037811 DOI: 10.3390/ijms17091536] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 09/02/2016] [Accepted: 09/05/2016] [Indexed: 01/02/2023] Open
Abstract
New approaches for visualisation of silicon nanoparticles (SiNPs) in cancer cells are realised by means of the linear and nonlinear optics in vitro. Aqueous colloidal solutions of SiNPs with sizes of about 10-40 nm obtained by ultrasound grinding of silicon nanowires were introduced into breast cancer cells (MCF-7 cell line). Further, the time-varying nanoparticles enclosed in cell structures were visualised by high-resolution structured illumination microscopy (HR-SIM) and micro-Raman spectroscopy. Additionally, the nonlinear optical methods of two-photon excited fluorescence (TPEF) and coherent anti-Stokes Raman scattering (CARS) with infrared laser excitation were applied to study the localisation of SiNPs in cells. Advantages of the nonlinear methods, such as rapid imaging, which prevents cells from overheating and larger penetration depth compared to the single-photon excited HR-SIM, are discussed. The obtained results reveal new perspectives of the multimodal visualisation and precise detection of the uptake of biodegradable non-toxic SiNPs by cancer cells and they are discussed in view of future applications for the optical diagnostics of cancer tumours.
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Affiliation(s)
- Elen Tolstik
- Leibniz Institute of Photonic Technology, Jena 07745, Germany.
| | - Liubov A Osminkina
- Physics Department, Lomonosov Moscow State University, Moscow 119991, Russia.
- Interational Laboratory "Bio-Nanophotonics", National Research Nuclear University "Moscow Engineering Physics Institute", Moscow 115409, Russia.
| | - Denis Akimov
- Leibniz Institute of Photonic Technology, Jena 07745, Germany.
| | - Maksim B Gongalsky
- Physics Department, Lomonosov Moscow State University, Moscow 119991, Russia.
| | - Andrew A Kudryavtsev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Pushino 142290, Russia.
| | - Victor Yu Timoshenko
- Physics Department, Lomonosov Moscow State University, Moscow 119991, Russia.
- Interational Laboratory "Bio-Nanophotonics", National Research Nuclear University "Moscow Engineering Physics Institute", Moscow 115409, Russia.
| | - Rainer Heintzmann
- Leibniz Institute of Photonic Technology, Jena 07745, Germany.
- Institute of Physical Chemistry, Abbe Center of Photonics, Friedrich-Schiller-University, Jena 07743, Germany.
| | | | - Jürgen Popp
- Leibniz Institute of Photonic Technology, Jena 07745, Germany.
- Institute of Physical Chemistry, Abbe Center of Photonics, Friedrich-Schiller-University, Jena 07743, Germany.
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Heuke S, Chernavskaia O, Bocklitz T, Legesse FB, Meyer T, Akimov D, Dirsch O, Ernst G, von Eggeling F, Petersen I, Guntinas-Lichius O, Schmitt M, Popp J. Multimodal nonlinear microscopy of head and neck carcinoma - toward surgery assisting frozen section analysis. Head Neck 2016; 38:1545-52. [PMID: 27098552 DOI: 10.1002/hed.24477] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 01/06/2016] [Accepted: 03/16/2016] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Treatment of early cancer stages is deeply connected to a good prognosis, a moderate reduction of the quality of life, and comparably low treatment costs. METHODS Head and neck squamous cell carcinomas were investigated using the multimodal combination of coherent anti-Stokes Raman scattering (CARS), two-photon excited fluorescence (TPEF), and second-harmonic generation (SHG) microscopy. RESULTS An increased median TPEF to CARS contrast was found comparing cancerous and healthy squamous epithelium with a p value of 1.8·10(-10) . A following comprehensive image analysis was able to predict the diagnosis of imaged tissue sections with an overall accuracy of 90% for a 4-class model. CONCLUSION Nonlinear multimodal imaging is verified objectively as a valuable diagnostic tool that complements conventional staining protocols and can serve as filter in future clinical routine reducing the pathologist's workload. © 2016 Wiley Periodicals, Inc. Head Neck 38: First-1552, 2016.
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Affiliation(s)
- Sandro Heuke
- Leibniz Institute of Photonic Technology, Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University, Jena, Germany
| | - Olga Chernavskaia
- Leibniz Institute of Photonic Technology, Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University, Jena, Germany
| | - Thomas Bocklitz
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University, Jena, Germany
| | - Fisseha Bekele Legesse
- Leibniz Institute of Photonic Technology, Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University, Jena, Germany
| | - Tobias Meyer
- Leibniz Institute of Photonic Technology, Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University, Jena, Germany
| | - Denis Akimov
- Leibniz Institute of Photonic Technology, Jena, Germany
| | - Olaf Dirsch
- Institute of Pathology, Klinikum Chemnitz, Chemnitz, Germany
| | - Günther Ernst
- Leibniz Institute of Photonic Technology, Jena, Germany.,Department of Otorhinolaryngology, Jena University Hospital, Jena, Germany
| | - Ferdinand von Eggeling
- Leibniz Institute of Photonic Technology, Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University, Jena, Germany.,Department of Otorhinolaryngology, Jena University Hospital, Jena, Germany
| | - Iver Petersen
- Institute of Pathology, Jena University Hospital, Jena, Germany
| | | | - Michael Schmitt
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University, Jena, Germany
| | - Jürgen Popp
- Leibniz Institute of Photonic Technology, Jena, Germany. .,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University, Jena, Germany.
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Lis D, Cecchet F. Localized surface plasmon resonances in nanostructures to enhance nonlinear vibrational spectroscopies: towards an astonishing molecular sensitivity. Beilstein J Nanotechnol 2014; 5:2275-92. [PMID: 25551056 PMCID: PMC4273228 DOI: 10.3762/bjnano.5.237] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 11/04/2014] [Indexed: 05/20/2023]
Abstract
Vibrational transitions contain some of the richest fingerprints of molecules and materials, providing considerable physicochemical information. Vibrational transitions can be characterized by different spectroscopies, and alternatively by several imaging techniques enabling to reach sub-microscopic spatial resolution. In a quest to always push forward the detection limit and to lower the number of needed vibrational oscillators to get a reliable signal or imaging contrast, surface plasmon resonances (SPR) are extensively used to increase the local field close to the oscillators. Another approach is based on maximizing the collective response of the excited vibrational oscillators through molecular coherence. Both features are often naturally combined in vibrational nonlinear optical techniques. In this frame, this paper reviews the main achievements of the two most common vibrational nonlinear optical spectroscopies, namely surface-enhanced sum-frequency generation (SE-SFG) and surface-enhanced coherent anti-Stokes Raman scattering (SE-CARS). They can be considered as the nonlinear counterpart and/or combination of the linear surface-enhanced infrared absorption (SEIRA) and surface-enhanced Raman scattering (SERS) techniques, respectively, which are themselves a branching of the conventional IR and spontaneous Raman spectroscopies. Compared to their linear equivalent, those nonlinear vibrational spectroscopies have proved to reach higher sensitivity down to the single molecule level, opening the way to astonishing perspectives for molecular analysis.
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Affiliation(s)
- Dan Lis
- Research Centre in Physics of Matter and Radiation (PMR), University of Namur (UNamur), 61 rue de Bruxelles, B-5000 Namur, Belgium
| | - Francesca Cecchet
- Research Centre in Physics of Matter and Radiation (PMR), University of Namur (UNamur), 61 rue de Bruxelles, B-5000 Namur, Belgium
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Lei TC, Masihzadeh O, Kahook MY, Ammar DA. Imaging the effects of prostaglandin analogues on cultured trabecular meshwork cells by coherent anti-stokes Raman scattering. Invest Ophthalmol Vis Sci 2013; 54:5972-80. [PMID: 23900606 DOI: 10.1167/iovs.13-12065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The aim of this study was to nondestructively monitor morphological changes to the lipid membranes of primary cultures of living human trabecular meshwork cells (hTMC) without the application of exogenous label. METHODS Live hTMC were imaged using two nonlinear optical techniques: coherent anti-Stokes Raman scattering (CARS) and two-photon autofluorescence (TPAF). The hTMC were treated with a commercial formulation of latanoprost (0.5 μg/mL) for 24 hours before imaging. Untreated cells and cells treated with vehicle containing the preservative benzalkonium chloride (BAK; 2 μg/mL) were imaged as controls. After CARS/TPAF imaging, hTMC were fixed, stained with the fluorescent lipid dye Nile Red, and imaged by conventional confocal microscopy to verify lipid membrane structures. RESULTS Analysis of CARS/TPAF images of hTMC treated with latanoprost revealed multiple intracellular lipid membranes absent from untreated or BAK-treated hTMC. Treatment of hTMC with sodium fluoride or ouabain, agents shown to cause morphological changes to hTMC, also did not induce formation of intracellular lipid membranes. CONCLUSIONS CARS microscopy detected changes in living hTMC morphology that were validated by subsequent histological stain. Prostaglandin-induced changes to hTMC involved rearrangement of lipid membranes within these cells. These in vitro results identify a novel biological response to a class of antiglaucoma drugs, and further experiments are needed to establish how this effect is involved in the hypotensive action of prostaglandin analogues in vivo.
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Affiliation(s)
- Tim C Lei
- Department of Electrical Engineering, University of Colorado Denver, Denver, Colorado, USA
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Ammar DA, Lei TC, Kahook MY, Masihzadeh O. Imaging the intact mouse cornea using coherent anti-stokes Raman scattering (CARS). Invest Ophthalmol Vis Sci 2013; 54:5258-65. [PMID: 23821187 DOI: 10.1167/iovs.12-11513] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE The aim of this study was to image the cellular and noncellular structures of the cornea and limbus in an intact mouse eye using the vibrational oscillation of the carbon-hydrogen bond in lipid membranes and autofluorescence as label-free contrast agents. METHODS Freshly enucleated mouse eyes were imaged using two nonlinear optical techniques: coherent anti-Stokes Raman scattering (CARS) and two-photon autofluorescence (TPAF). Sequential images were collected through the full thickness of the cornea and limbal regions. Line scans along the transverse/sagittal axes were also performed. RESULTS Analysis of multiple CARS/TPAF images revealed that corneal epithelial and endothelial cells could be identified by the lipid-rich plasma membrane CARS signal. The fluorescent signal from the collagen fibers of the corneal stroma was evident in the TPAF channel. The transition from the cornea to sclera at the limbus was marked by a change in collagen pattern (TPAF channel) and thickness of surface cells (CARS channel). Regions within the corneal stroma that lack collagen autofluorescence coincided with CARS signal, indicating the presence of stromal fibroblasts or nerve fibers. CONCLUSIONS The CARS technique was successful in imaging cells in the intact mouse eye, both at the surface and within corneal tissue. Multiphoton images were comparable to histologic sections. The methods described here represent a new avenue for molecular specific imaging of the mouse eye. The lack of need for tissue fixation is unique compared with traditional histology imaging techniques.
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Affiliation(s)
- David A Ammar
- Department of Ophthalmology, University of Colorado Denver, Aurora, Colorado 80045, USA
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Masihzadeh O, Ammar DA, Kahook MY, Lei TC. Coherent anti-stokes Raman scattering (CARS) microscopy: a novel technique for imaging the retina. Invest Ophthalmol Vis Sci 2013; 54:3094-101. [PMID: 23580484 DOI: 10.1167/iovs.13-11642] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To image the cellular and noncellular structures of the retina in an intact mouse eye without the application of exogenous fluorescent labels using noninvasive, nondestructive techniques. METHODS Freshly enucleated mouse eyes were imaged using two nonlinear optical techniques: coherent anti-Stokes Raman scattering (CARS) and two-photon autofluorescence (TPAF). Cross sectional transverse sections and sequential flat (en face) sagittal sections were collected from a region of sclera approximately midway between the limbus and optic nerve. Imaging proceeded from the surface of the sclera to a depth of ∼60 μm. RESULTS The fluorescent signal from collagen fibers within the sclera was evident in the TPAF channel; the scleral collagen fibers showed no organization and appeared randomly packed. The sclera contained regions lacking TPAF and CARS fluorescence of ∼3 to 15 μm in diameter that could represent small vessels or scleral fibroblasts. Intense punctate CARS signals from the retinal pigment epithelial layer were of a size and shape of retinyl storage esters. Rod outer segments could be identified by the CARS signal from their lipid-rich plasma membranes. CONCLUSIONS CARS microscopy can be used to image the outer regions of the mammalian retina without the use of a fluorescent dye or exogenously expressed recombinant protein. With technical advancements, CARS/TPAF may represent a new avenue for noninvasively imaging the retina and might complement modalities currently used in clinical practice.
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Affiliation(s)
- Omid Masihzadeh
- Department of Ophthalmology, University of Colorado Denver, Aurora, Colorado, USA
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