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Rzepiela J, Liberka M, Zychowicz M, Wang J, Tokoro H, Piotrowska K, Baś S, Ohkoshi SI, Chorazy S. SHG-active luminescent thermometers based on chiral cyclometalated dicyanidoiridate(iii) complexes. Inorg Chem Front 2024; 11:1366-1380. [PMID: 38420599 PMCID: PMC10897766 DOI: 10.1039/d3qi02482b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 01/12/2024] [Indexed: 03/02/2024]
Abstract
Multifunctional optical materials can be realized by combining stimuli-responsive photoluminescence (PL), e.g., optical thermometry, with non-linear optical (NLO) effects, such as second-harmonic generation (SHG). We report a novel approach towards SHG-active luminescent thermometers achieved by constructing unique iridium(iii) complexes, cis-[IrIII(CN)2(R,R-pinppy)2]- (R,R-pinppy = (R,R)-2-phenyl-4,5-pinenopyridine), bearing both a chiral 2-phenylpyridine derivative and cyanido ligands, the latter enabling the formation of a series of molecular materials: (TBA)[IrIII(CN)2(R,R-pinppy)2]·2MeCN (1) (TBA+ = tetrabutylammonium) and (nBu-DABCO)2[IrIII(CN)2(R,R-pinppy)2](i)·MeCN (2) (nBu-DABCO+ = 1-(n-butyl)-1,4-diazabicyclo-[2.2.2]octan-1-ium) hybrid salts, (TBA)2{[LaIII(NO3)3(H2O)0.5]2[IrIII(CN)2(R,R-pinppy)2]2} (3) square molecules, and {[LaIII(NO3)2(dmf)3][IrIII(CN)2(R,R-pinppy)2]}·MeCN (4) coordination chains. Thanks to the chiral pinene group, 1-4 crystallize in non-centrosymmetric space groups leading to SHG activity, while the N,C-coordination of ppy-type ligands to Ir(iii) centers generates visible charge-transfer (CT) photoluminescence. The PL characteristics are distinctly temperature-dependent which was utilized in achieving ratiometric optical thermometry below 220 K. The PL phenomena were rationalized by DFT/TD-DFT calculations indicating an MLCT-type of the emission in obtained Ir(iii) complexes with the rich vibronic structure providing a few emission bands that variously depend on temperature due to the role of thermally activated vibrations. As these crucial vibrational modes depend on the crystal lattice, the thermometry performance differs within 1-4 being the most efficient in 4 while the SHG is by far the best also for 4. This proves that pinene-functionalized cyclometalated dicyanidoiridates(iii) are great prerequisites for tunable PL-NLO conjunction with the most effective multifunctionality ensured by the insertion of these anions into bimetallic frameworks.
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Affiliation(s)
- Jan Rzepiela
- Faculty of Chemistry, Jagiellonian University Gronostajowa 2 30-387 Kraków Poland
- Jagiellonian University, Doctoral School of Exact and Natural Sciences Łojasiewicza 11 30-348 Kraków Poland
| | - Michal Liberka
- Faculty of Chemistry, Jagiellonian University Gronostajowa 2 30-387 Kraków Poland
- Jagiellonian University, Doctoral School of Exact and Natural Sciences Łojasiewicza 11 30-348 Kraków Poland
| | - Mikolaj Zychowicz
- Faculty of Chemistry, Jagiellonian University Gronostajowa 2 30-387 Kraków Poland
- Jagiellonian University, Doctoral School of Exact and Natural Sciences Łojasiewicza 11 30-348 Kraków Poland
| | - Junhao Wang
- Department of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba 1-1-1 Tennodai Tsukuba Ibaraki 305-8573 Japan
- Department of Chemistry, School of Science, The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-0033 Japan
| | - Hiroko Tokoro
- Department of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba 1-1-1 Tennodai Tsukuba Ibaraki 305-8573 Japan
| | - Kinga Piotrowska
- Faculty of Chemistry, Jagiellonian University Gronostajowa 2 30-387 Kraków Poland
- Jagiellonian University, Doctoral School of Exact and Natural Sciences Łojasiewicza 11 30-348 Kraków Poland
| | - Sebastian Baś
- Faculty of Chemistry, Jagiellonian University Gronostajowa 2 30-387 Kraków Poland
| | - Shin-Ichi Ohkoshi
- Department of Chemistry, School of Science, The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-0033 Japan
| | - Szymon Chorazy
- Faculty of Chemistry, Jagiellonian University Gronostajowa 2 30-387 Kraków Poland
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Aghigh A, Bancelin S, Rivard M, Pinsard M, Ibrahim H, Légaré F. Second harmonic generation microscopy: a powerful tool for bio-imaging. Biophys Rev 2023; 15:43-70. [PMID: 36909955 PMCID: PMC9995455 DOI: 10.1007/s12551-022-01041-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 12/21/2022] [Indexed: 01/20/2023] Open
Abstract
Second harmonic generation (SHG) microscopy is an important optical imaging technique in a variety of applications. This article describes the history and physical principles of SHG microscopy and its more advanced variants, as well as their strengths and weaknesses in biomedical applications. It also provides an overview of SHG and advanced SHG imaging in neuroscience and microtubule imaging and how these methods can aid in understanding microtubule formation, structuration, and involvement in neuronal function. Finally, we offer a perspective on the future of these methods and how technological advancements can help make SHG microscopy a more widely adopted imaging technique.
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Affiliation(s)
- Arash Aghigh
- Centre Énergie Matériaux Télécommunications, Institut National de La Recherche Scientifique, Varennes, QC Canada
| | | | - Maxime Rivard
- National Research Council Canada, Boucherville, QC Canada
| | - Maxime Pinsard
- Institut National de Recherche en Sciences Et Technologies Pour L’environnement Et L’agriculture, Paris, France
| | - Heide Ibrahim
- Centre Énergie Matériaux Télécommunications, Institut National de La Recherche Scientifique, Varennes, QC Canada
| | - François Légaré
- Centre Énergie Matériaux Télécommunications, Institut National de La Recherche Scientifique, Varennes, QC Canada
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3
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Page EF, Blake MJ, Foley GA, Calhoun TR. Monitoring membranes: The exploration of biological bilayers with second harmonic generation. CHEMICAL PHYSICS REVIEWS 2022; 3:041307. [PMID: 36536669 PMCID: PMC9756348 DOI: 10.1063/5.0120888] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 11/03/2022] [Indexed: 12/23/2022]
Abstract
Nature's seemingly controlled chaos in heterogeneous two-dimensional cell membranes stands in stark contrast to the precise, often homogeneous, environment in an experimentalist's flask or carefully designed material system. Yet cell membranes can play a direct role, or serve as inspiration, in all fields of biology, chemistry, physics, and engineering. Our understanding of these ubiquitous structures continues to evolve despite over a century of study largely driven by the application of new technologies. Here, we review the insight afforded by second harmonic generation (SHG), a nonlinear optical technique. From potential measurements to adsorption and diffusion on both model and living systems, SHG complements existing techniques while presenting a large exploratory space for new discoveries.
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Affiliation(s)
- Eleanor F. Page
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Marea J. Blake
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Grant A. Foley
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Tessa R. Calhoun
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
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4
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Zhao Y, Fuji T. Two-dimensional free space electric field imaging using electric field induced second harmonic generation. OPTICS LETTERS 2022; 47:2999-3002. [PMID: 35709035 DOI: 10.1364/ol.460742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
We present a new, to the best of our knowledge, approach for the measurement of the localized electric field distribution in air using electric field induced second harmonic generation combined with a microscopic imaging technique. This method only needs two snapshot second harmonic images with orthogonal polarizations to obtain the two-dimensional spatial distribution of the intensity and direction of the electric field. The distribution of a local electric field was clearly measured with a spatial resolution of 8.8 µm by using this method. The measurement of a single second harmonic image takes 5 s by using a 5 kHz repetition rate femtosecond laser.
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5
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Khadria A. Tools to measure membrane potential of neurons. Biomed J 2022; 45:749-762. [DOI: 10.1016/j.bj.2022.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 05/08/2022] [Accepted: 05/29/2022] [Indexed: 12/31/2022] Open
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Riazanski V, Mauleon G, Zimnicka AM, Chen S, Nelson DJ. Phagosomal chloride dynamics in the alveolar macrophage. iScience 2022; 25:103636. [PMID: 35024579 PMCID: PMC8733233 DOI: 10.1016/j.isci.2021.103636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 10/11/2021] [Accepted: 12/14/2021] [Indexed: 12/04/2022] Open
Abstract
Acidification in intracellular organelles is tightly linked to the influx of Cl- counteracting proton translocation by the electrogenic V-ATPase. We quantified the dynamics of Cl- transfer accompanying cargo incorporation into single phagosomes in alveolar macrophages (AMs). Phagosomal Cl- concentration and acidification magnitude were followed in real time with maximal acidification achieved at levels of approximately 200 mM. Live cell confocal microscopy verified that phagosomal Cl- influx utilized predominantly the Cl- channel CFTR. Relative levels of elemental chlorine (Cl) in hard X-ray fluorescence microprobe (XFM) analysis within single phagosomes validated the increase in Cl- content. XFM revealed the complex interplay between elemental K content inside the phagosome and changes in Cl- during phagosomal particle uptake. Cl- -dependent changes in phagosomal membrane potential were obtained using second harmonic generation (SHG) microscopy. These studies provide a mechanistic insight for screening studies in drug development targeting pulmonary inflammatory disease.
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Affiliation(s)
- Vladimir Riazanski
- The University of Chicago, Department of Pharmacological and Physiological Sciences, 947 E. 58th Street, MC 0926, Chicago, IL 60637, USA
| | - Gerardo Mauleon
- The University of Chicago, Department of Pharmacological and Physiological Sciences, 947 E. 58th Street, MC 0926, Chicago, IL 60637, USA
| | - Adriana M. Zimnicka
- The University of Chicago, Department of Pharmacological and Physiological Sciences, 947 E. 58th Street, MC 0926, Chicago, IL 60637, USA
| | - Si Chen
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Deborah J. Nelson
- The University of Chicago, Department of Pharmacological and Physiological Sciences, 947 E. 58th Street, MC 0926, Chicago, IL 60637, USA
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7
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Li B, Li J, Gan W, Tan Y, Yuan Q. Unveiling the Molecular Dynamics in a Living Cell to the Subcellular Organelle Level Using Second-Harmonic Generation Spectroscopy and Microscopy. Anal Chem 2021; 93:14146-14152. [PMID: 34648265 DOI: 10.1021/acs.analchem.1c02604] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Second-harmonic generation (SHG) microscopy has been proved to be a powerful method for investigating the structures of biomaterials. SHG spectra were also generally used to probe the adsorption and cross-membrane transport of molecules on lipid bilayers in situ and in real time. In this work, we applied SHG and two-photon fluorescence (TPF) spectra to investigate the dynamics of an amphiphilic ion with an SHG and TPF chromophore, D289 (4-(4-diethylaminostyry)-1-methyl-pyridinium iodide), on the surface of human chronic myelogenous leukemia (K562) cells and the subcellular structures inside the cells. The adsorption and cross-membrane transport of D289 into the cells and then into the organelles such as mitochondria were revealed. SHG images were also recorded and used to demonstrate their capability of probing molecular dynamics in organelles in K562 cells. This work demonstrated the first SHG investigation of the cross-membrane transport dynamics on the surface of subcellular organelles. It may also shed light on the differentiation of different types of subcellular structures in cells.
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Affiliation(s)
- Bifei Li
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, Also School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong; School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
| | - Jianhui Li
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, Also School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong; School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
| | - Wei Gan
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, Also School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong; School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
| | - Ying Tan
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Biology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong 518055, China
| | - Qunhui Yuan
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, Also School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China
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8
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Lanin AA, Chebotarev AS, Kelmanson IV, Pochechuev MS, Fetisova ES, Bilan DS, Shevchenko EK, Ivanov AA, Fedotov AB, Belousov VV, Zheltikov AM. Single-beam multimodal nonlinear-optical imaging of structurally complex events in cell-cycle dynamics. JPHYS PHOTONICS 2021. [DOI: 10.1088/2515-7647/ac159a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract
We demonstrate a multimodal nonlinear-optical imaging that combines second- and third-harmonic generation (SHG and THG) with three-photon-excited fluorescence (3PEF) as a means to resolve fine details of the cell structure and trace its transformations throughout structurally complex episodes of cell-cycle dynamics, including the key stages and signatures in cell division. When zoomed in on cell mitosis, this technique enables a high-contrast multimodal imaging of intra- and extracellular signatures of cell division, detecting, via a multiplex, 3PEF/SHG/THG readout, a remarkable diversity of shapes, sizes, and symmetries in a truly single-beam setting, with no need for beam refocusing or field-waveform re-adjustment.
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Bouquiaux C, Castet F, Champagne B. Unravelling the Effects of Cholesterol on the Second-Order Nonlinear Optical Responses of Di-8-ANEPPS Dye Embedded in Phosphatidylcholine Lipid Bilayers. J Phys Chem B 2021; 125:10195-10212. [PMID: 34491062 DOI: 10.1021/acs.jpcb.1c05630] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cholesterol is known for its role in maintaining the correct fluidity and rigidity of the animals cell membranes and thus their functions. Assessing the content and the role of cholesterol in lipid bilayers is therefore of crucial importance for a deeper understanding and control of membrane functioning. In this computational work, we investigate bilayers built from three types of glycerophospholipid phosphatidylcholine (PC) lipids, namely dipalmitoylphosphatidylcholine (DPPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and dioleoylphosphatidylcholine (DOPC), and containing different amounts of cholesterol by analyzing the second-harmonic generation (SHG) nonlinear optical (NLO) response of a probe molecule, di-8-ANEPPS, inserted into the membranes. This molecular property presents the advantage to be specific to interfacial regions such as lipid bilayers. To unravel these effects, Molecular Dynamics (MD) simulations have been performed on both DPPC and DOPC lipids by varying the cholesterol mole fraction (from 0 to 0.66), while POPC was only considered as a pure bilayer. In the case of the structural properties of the bilayers, all the analyses converge toward the same conclusion: as the mole fraction of cholesterol increases, the systems become more rigid, confirming the condensing effect of cholesterol. In addition, the chromophore is progressively more aligned with respect to the normal to the bilayer. On the contrary, addition of unsaturation disorders the lipid bilayers, with barely no impact on the alignment of the chromophore. Then, using the frames obtained from the MD simulations, the first hyperpolarizability β of the dye in its environment has been computed at the TDDFT level. On the one hand, the addition of cholesterol induces a progressive increase of the diagonal component the β tensor parallel to the bilayer normal. On the other hand, larger β values have been calculated for the unsaturated than for the saturated lipid systems. In summary, this study illustrates the relationship between the composition and structure of the bilayers and the NLO responses of the embedded dye.
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Affiliation(s)
- Charlotte Bouquiaux
- Theoretical Chemistry Lab, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, rue de Bruxelles, 61, B-5000 Namur, Belgium
| | - Frédéric Castet
- , Institut des Sciences Moléculaires, UMR 5255 CNRS, University of Bordeaux, cours de la Libération 351, F-33405 Talence Cedex, France
| | - Benoît Champagne
- Theoretical Chemistry Lab, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, rue de Bruxelles, 61, B-5000 Namur, Belgium
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10
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Narasimhan M, Gallei M, Tan S, Johnson A, Verstraeten I, Li L, Rodriguez L, Han H, Himschoot E, Wang R, Vanneste S, Sánchez-Simarro J, Aniento F, Adamowski M, Friml J. Systematic analysis of specific and nonspecific auxin effects on endocytosis and trafficking. PLANT PHYSIOLOGY 2021; 186:1122-1142. [PMID: 33734402 PMCID: PMC8195513 DOI: 10.1093/plphys/kiab134] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 01/23/2021] [Indexed: 05/08/2023]
Abstract
The phytohormone auxin and its directional transport through tissues are intensively studied. However, a mechanistic understanding of auxin-mediated feedback on endocytosis and polar distribution of PIN auxin transporters remains limited due to contradictory observations and interpretations. Here, we used state-of-the-art methods to reexamine the auxin effects on PIN endocytic trafficking. We used high auxin concentrations or longer treatments versus lower concentrations and shorter treatments of natural indole-3-acetic acid (IAA) and synthetic naphthalene acetic acid (NAA) auxins to distinguish between specific and nonspecific effects. Longer treatments of both auxins interfere with Brefeldin A-mediated intracellular PIN2 accumulation and also with general aggregation of endomembrane compartments. NAA treatment decreased the internalization of the endocytic tracer dye, FM4-64; however, NAA treatment also affected the number, distribution, and compartment identity of the early endosome/trans-Golgi network, rendering the FM4-64 endocytic assays at high NAA concentrations unreliable. To circumvent these nonspecific effects of NAA and IAA affecting the endomembrane system, we opted for alternative approaches visualizing the endocytic events directly at the plasma membrane (PM). Using total internal reflection fluorescence microscopy, we saw no significant effects of IAA or NAA treatments on the incidence and dynamics of clathrin foci, implying that these treatments do not affect the overall endocytosis rate. However, both NAA and IAA at low concentrations rapidly and specifically promoted endocytosis of photo-converted PIN2 from the PM. These analyses identify a specific effect of NAA and IAA on PIN2 endocytosis, thus, contributing to its polarity maintenance and furthermore illustrate that high auxin levels have nonspecific effects on trafficking and endomembrane compartments.
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Affiliation(s)
| | - Michelle Gallei
- Institute of Science and Technology (IST), Klosterneuburg 3400, Austria
| | - Shutang Tan
- Institute of Science and Technology (IST), Klosterneuburg 3400, Austria
| | - Alexander Johnson
- Institute of Science and Technology (IST), Klosterneuburg 3400, Austria
| | - Inge Verstraeten
- Institute of Science and Technology (IST), Klosterneuburg 3400, Austria
| | - Lanxin Li
- Institute of Science and Technology (IST), Klosterneuburg 3400, Austria
| | - Lesia Rodriguez
- Institute of Science and Technology (IST), Klosterneuburg 3400, Austria
| | - Huibin Han
- Institute of Science and Technology (IST), Klosterneuburg 3400, Austria
| | - Ellie Himschoot
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
| | - Ren Wang
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
| | - Steffen Vanneste
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Judit Sánchez-Simarro
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universitat de Valencia, 46100 Burjassot, Spain
| | - Fernando Aniento
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universitat de Valencia, 46100 Burjassot, Spain
| | - Maciek Adamowski
- Institute of Science and Technology (IST), Klosterneuburg 3400, Austria
| | - Jiří Friml
- Institute of Science and Technology (IST), Klosterneuburg 3400, Austria
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11
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Wang C, Wen Y, Sun J, Zhou J. Broadband second-harmonic generation from artificial optical nonlinearity. OPTICS LETTERS 2021; 46:2368-2371. [PMID: 33988585 DOI: 10.1364/ol.423200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/16/2021] [Indexed: 06/12/2023]
Abstract
In this Letter, we present a mechanism for effectively broadening the bandwidth of second-harmonic generation (SHG) with the metamaterial-based artificial optical nonlinearity. As the nonlinear response of the artificial nonlinearity arising from the magnetoelectric coupling constructed by the meta-molecule (MM) structure, the broadband second-order nonlinearity can be built by simply combining the MMs with different geometrical sizes together. The physical model and the numerical simulation fully support the artificial generation and modulation of the broadband second harmonics. Our work suggests a new route for realizing the on-chip custom-designed nonlinear optical devices with broadband operation.
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12
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Mizuguchi T, Nuriya M. Applications of second harmonic generation (SHG)/sum-frequency generation (SFG) imaging for biophysical characterization of the plasma membrane. Biophys Rev 2020; 12:10.1007/s12551-020-00768-4. [PMID: 33108561 PMCID: PMC7755958 DOI: 10.1007/s12551-020-00768-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022] Open
Abstract
The plasma membrane is a lipid bilayer of < 10 nm width that separates intra- and extra-cellular environments and serves as the site of cell-cell communication, as well as communication between cells and the extracellular environment. As such, biophysical phenomena at and around the plasma membrane play key roles in determining cellular physiology and pathophysiology. Thus, the selective visualization and characterization of the plasma membrane are crucial aspects of research in wide areas of biology and medicine. However, the specific characterization of the plasma membrane has been a challenge using conventional imaging techniques, which are unable to effectively distinguish between signals arising from the plasma membrane and those from intracellular lipid structures. In this regard, interface-specific second harmonic generation (SHG) and sum-frequency generation (SFG) imaging demonstrate great potential. When combined with exogenous SHG/SFG active dyes, SHG/SFG can specifically highlight the plasma membrane as the most prominent interface associated with cells. Furthermore, SHG/SFG imaging can be readily extended to multimodal multiphoton microscopy with simultaneous occurrence of other multiphoton phenomena, including multiphoton excitation and coherent Raman scattering, which shed light on the biophysical properties of the plasma membrane from different perspectives. Here, we review traditional and current applications, as well as the prospects of long-known but unexplored SHG/SFG imaging techniques in biophysics, with special focus on their use in the biophysical characterization of the plasma membrane.
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Affiliation(s)
- Takaha Mizuguchi
- Department of Pharmacology School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Mutsuo Nuriya
- Department of Pharmacology School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, 332-0012, Japan.
- Keio Advanced Research Center for Water Biology and Medicine, Keio University, 2-15-45 Mita, Minato-ku, Tokyo, 108-8345, Japan.
- Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Hodogaya, Yokohama, Kanagawa, 240-8501, Japan.
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13
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Bouquiaux C, Tonnelé C, Castet F, Champagne B. Second-Order Nonlinear Optical Properties of an Amphiphilic Dye Embedded in a Lipid Bilayer. A Combined Molecular Dynamics–Quantum Chemistry Study. J Phys Chem B 2020; 124:2101-2109. [DOI: 10.1021/acs.jpcb.9b10988] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Charlotte Bouquiaux
- Theoretical Chemistry Laboratory, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, B-5000 Namur, Belgium
| | - Claire Tonnelé
- University of Bordeaux, Institut des Sciences Moléculaires, UMR 5255 CNRS, Cours de la Libération 351, F-33405 Talence Cedex, France
| | - Frédéric Castet
- University of Bordeaux, Institut des Sciences Moléculaires, UMR 5255 CNRS, Cours de la Libération 351, F-33405 Talence Cedex, France
| | - Benoît Champagne
- Theoretical Chemistry Laboratory, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, B-5000 Namur, Belgium
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14
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Lanin AA, Pochechuev MS, Chebotarev AS, Kelmanson IV, Belousov VV, Zheltikov AM. Nonlinear-optical stain-free stereoimaging of astrocytes and gliovascular interfaces. JOURNAL OF BIOPHOTONICS 2019; 12:e201800432. [PMID: 30891920 DOI: 10.1002/jbio.201800432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 03/10/2019] [Accepted: 03/17/2019] [Indexed: 06/09/2023]
Abstract
Methods of nonlinear optics provide a vast arsenal of tools for label-free brain imaging, offering a unique combination of chemical specificity, the ability to detect fine morphological features, and an unprecedentedly high, subdiffraction spatial resolution. While these techniques provide a rapidly growing platform for the microscopy of neurons and fine intraneural structures, optical imaging of astroglia still largely relies on filament-protein-antibody staining, subject to limitations and difficulties especially severe in live-brain studies. Once viewed as an ancillary, inert brain scaffold, astroglia are being promoted, as a part of an ongoing paradigm shift in neurosciences, into the role of a key active agent of intercellular communication and information processing, playing a significant role in brain functioning under normal and pathological conditions. Here, we show that methods of nonlinear optics provide a unique resource to address long-standing challenges in label-free astroglia imaging. We demonstrate that, with a suitable beam-focusing geometry and careful driver-pulse compression, microscopy of second-harmonic generation (SHG) can enable a high-resolution label-free imaging of fibrillar structures of astrocytes, most notably astrocyte processes and their endfeet. SHG microscopy of astrocytes is integrated in our approach with nonlinear-optical imaging of red blood cells based on third-harmonic generation (THG) enhanced by a three-photon resonance with the Soret band of hemoglobin. With astroglia and red blood cells providing two physically distinct imaging contrasts in SHG and THG channels, a parallel detection of the second and third harmonics enables a high-contrast, high-resolution, stain-free stereoimaging of gliovascular interfaces in the central nervous system. Transverse scans of the second and third harmonics are shown to resolve an ultrafine texture of blood-vessel walls and astrocyte-process endfeet on gliovascular interfaces with a spatial resolution within 1 μm at focusing depths up to 20 μm inside a brain.
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Affiliation(s)
- Aleksandr A Lanin
- Physics Department, International Laser Center, M.V. Lomonosov Moscow State University, Moscow, Russia
- Russian Quantum Center, Moscow, Russia
| | - Matvei S Pochechuev
- Physics Department, International Laser Center, M.V. Lomonosov Moscow State University, Moscow, Russia
- Kurchatov Institute National Research Center, Moscow, Russia
| | - Artem S Chebotarev
- Physics Department, International Laser Center, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Ilya V Kelmanson
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Vsevolod V Belousov
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Aleksei M Zheltikov
- Physics Department, International Laser Center, M.V. Lomonosov Moscow State University, Moscow, Russia
- Russian Quantum Center, Moscow, Russia
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas
- Kurchatov Institute National Research Center, Moscow, Russia
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15
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Lim H. Harmonic Generation Microscopy 2.0: New Tricks Empowering Intravital Imaging for Neuroscience. Front Mol Biosci 2019; 6:99. [PMID: 31649934 PMCID: PMC6794408 DOI: 10.3389/fmolb.2019.00099] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 09/17/2019] [Indexed: 01/08/2023] Open
Abstract
Optical harmonic generation, e.g., second- (SHG) and third-harmonic generation (THG), provides intrinsic contrasts for three-dimensional intravital microscopy. Contrary to two-photon excited fluorescence (TPEF), however, they have found relatively specialized applications, such as imaging collagenous and non-specific tissues, respectively. Here we review recent advances that broaden the capacity of SHG and THG for imaging the central nervous system in particular. The fundamental contrast mechanisms are reviewed as they encode novel information including molecular origin, spectroscopy, functional probes, and image analysis, which lay foundations for promising future applications in neuroscience.
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Affiliation(s)
- Hyungsik Lim
- Department of Physics and Astronomy, Hunter College and the Graduate Center of the City University of New York, New York, NY, United States
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16
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Miller LN, Brewer WT, Williams JD, Fozo EM, Calhoun TR. Second Harmonic Generation Spectroscopy of Membrane Probe Dynamics in Gram-Positive Bacteria. Biophys J 2019; 117:1419-1428. [PMID: 31586521 DOI: 10.1016/j.bpj.2019.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/11/2019] [Accepted: 09/13/2019] [Indexed: 11/17/2022] Open
Abstract
Bacterial membranes are complex mixtures with dispersity that is dynamic over scales of both space and time. To capture adsorption onto and transport within these mixtures, we conduct simultaneous second harmonic generation (SHG) and two-photon fluorescence measurements on two different gram-positive bacterial species as the cells uptake membrane-specific probe molecules. Our results show that SHG not only can monitor the movement of small molecules across membrane leaflets but also is sensitive to higher-level ordering of the molecules within the membrane. Further, we show that the membranes of Staphylococcus aureus remain more dynamic after longer times at room temperature in comparison to Enterococcus faecalis. Our findings provide insight into the variability of activities seen between structurally similar molecules in gram-positive bacteria while also demonstrating the power of SHG to examine these dynamics.
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Affiliation(s)
- Lindsey N Miller
- Department of Chemistry, University of Tennesseee, Knoxville, Tennessee
| | - William T Brewer
- Department of Microbiology, University of Tennesseee, Knoxville, Tennessee
| | - Julia D Williams
- Department of Microbiology, University of Tennesseee, Knoxville, Tennessee
| | - Elizabeth M Fozo
- Department of Microbiology, University of Tennesseee, Knoxville, Tennessee
| | - Tessa R Calhoun
- Department of Chemistry, University of Tennesseee, Knoxville, Tennessee.
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17
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Pochechuev MS, Lanin AA, Kelmanson IV, Bilan DS, Kotova DA, Chebotarev AS, Tarabykin V, Fedotov AB, Belousov VV, Zheltikov AM. Stain-free subcellular-resolution astrocyte imaging using third-harmonic generation. OPTICS LETTERS 2019; 44:3166-3169. [PMID: 31199407 DOI: 10.1364/ol.44.003166] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 04/11/2019] [Indexed: 06/09/2023]
Abstract
We demonstrate stain-free, high-contrast, subcellular-resolution imaging of astroglial cells using epi-detected third-harmonic generation (THG). The astrocyte-imaging capability of THG is verified by colocalizing THG images with fluorescence images of astrocytes expressing a genetically encodable fluorescent reporter. We show that THG imaging with an optimized point-spread function can reliably detect significant subcellular features of astrocytes, including cell nuclei, as well as the soma shape and boundaries.
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18
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Khadria A, Fleischhauer J, Boczarow I, Wilkinson JD, Kohl MM, Anderson HL. Porphyrin Dyes for Nonlinear Optical Imaging of Live Cells. iScience 2018; 4:153-163. [PMID: 30240737 PMCID: PMC6147020 DOI: 10.1016/j.isci.2018.05.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/09/2018] [Accepted: 05/22/2018] [Indexed: 11/28/2022] Open
Abstract
Second harmonic generation (SHG)-based probes are useful for nonlinear optical imaging of biological structures, such as the plasma membrane. Several amphiphilic porphyrin-based dyes with high SHG coefficients have been synthesized with different hydrophilic head groups, and their cellular targeting has been studied. The probes with cationic head groups localize better at the plasma membrane than the neutral probes with zwitterionic or non-charged ethylene glycol-based head groups. Porphyrin dyes with only dications as hydrophilic head groups localize inside HEK293T cells to give SHG, whereas tricationic dyes localize robustly at the plasma membrane of cells, including neurons, in vitro and ex vivo. The copper(II) complex of the tricationic dye with negligible fluorescence quantum yield works as an SHG-only dye. The free-base tricationic dye has been demonstrated for two-photon fluorescence and SHG-based multimodal imaging. This study demonstrates the importance of a balance between the hydrophobicity and hydrophilicity of amphiphilic dyes for effective plasma membrane localization.
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Affiliation(s)
- Anjul Khadria
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, UK
| | - Jan Fleischhauer
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, UK
| | - Igor Boczarow
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, UK
| | - James D Wilkinson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, UK
| | - Michael M Kohl
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Harry L Anderson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, UK.
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19
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Khadria A, de Coene Y, Gawel P, Roche C, Clays K, Anderson HL. Push-pull pyropheophorbides for nonlinear optical imaging. Org Biomol Chem 2018; 15:947-956. [PMID: 28054076 DOI: 10.1039/c6ob02319c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pyropheophorbide-a methyl ester (PPa-OMe) has been modified by attaching electron-donor and -acceptor groups to alter its linear and nonlinear optical properties. Regioselective bromination of the terminal vinyl position and Suzuki coupling were used to attach a 4-(N,N-diethylaminophenyl) electron-donor group. The electron-acceptor dicyanomethylene was attached at the cyclic ketone position through a Knoevenagel condensation. Four different derivatives of PPa-OMe, containing either electron-donor or electron-acceptor groups, or both, were converted to hydrophilic bis-TEG amides to generate a series of amphiphilic dyes. The absorption and emission properties of all the dyes were compared to a previously reported push-pull type porphyrin-based dye and a commercial push-pull styryl dye, FM4-64. Electrochemical measurements reveal that the electron donor group causes a greater decrease in HOMO-LUMO gap than the electron-acceptor. TD-DFT calculations on optimized geometries (DFT) of all four dyes show that the HOMO is mostly localized on the donor, 4-(N,N-diethylaminophenyl), while the LUMO is distributed around the chlorin ring and the electron-acceptor. Hyper-Rayleigh scattering experiments show that the first-order hyperpolarizabilities of the dyes increase on attaching either electron-donor or -acceptor groups, having the highest value when both the donor and acceptor groups are attached. Two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) images of the bis-TEG amide attached dyes in lipid monolayer-coated droplets of water-in-oil reveal that the TPEF and SHG involve transition dipole moments in different orientations.
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Affiliation(s)
- Anjul Khadria
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, UK.
| | - Yovan de Coene
- Department of Chemistry, University of Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium.
| | - Przemyslaw Gawel
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, UK.
| | - Cécile Roche
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, UK.
| | - Koen Clays
- Department of Chemistry, University of Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium.
| | - Harry L Anderson
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, UK.
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20
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Nuriya M, Fukushima S, Momotake A, Shinotsuka T, Yasui M, Arai T. Multimodal two-photon imaging using a second harmonic generation-specific dye. Nat Commun 2016; 7:11557. [PMID: 27156702 PMCID: PMC4865818 DOI: 10.1038/ncomms11557] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 04/07/2016] [Indexed: 11/09/2022] Open
Abstract
Second harmonic generation (SHG) imaging can be used to visualize unique biological phenomena, but currently available dyes limit its application owing to the strong fluorescent signals that they generate together with SHG. Here we report the first non-fluorescent and membrane potential-sensitive SHG-active organic dye Ap3. Ap3 is photostable and generates SH signals at the plasma membrane with virtually no fluorescent signals, in sharp contrast to the previously used fluorescent dye FM4-64. When tested in neurons, Ap3-SHG shows linear membrane potential sensitivity and fast responses to action potentials, and also shows significantly reduced photodamage compared with FM4-64. The SHG-specific nature of Ap3 allows simultaneous and completely independent imaging of SHG signals and fluorescent signals from various reporter molecules, including markers of cellular organelles and intracellular calcium. Therefore, this SHG-specific dye enables true multimodal two-photon imaging in biological samples. Current dyes for second harmonic generation (SHG) imaging strongly fluoresce, limiting their application. Here the authors develop a SHG-specific dye, Ap3, that partitions into cell membranes, displays sensitivity to membrane potential and has virtually no fluorescence emission at SHG imaging wavelengths.
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Affiliation(s)
- Mutsuo Nuriya
- Department of Pharmacology School of Medicine, Keio University, 35 Shinanomachi, Tokyo 160-8582, Japan.,Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama 240-8501, Japan
| | - Shun Fukushima
- Graduate School of Pure and Applied Sciences and Tsukuba Research Center for Interdisciplinary Materials Science (TIMS), University of Tsukuba, Tsukuba 305-8577, Japan
| | - Atsuya Momotake
- Graduate School of Pure and Applied Sciences and Tsukuba Research Center for Interdisciplinary Materials Science (TIMS), University of Tsukuba, Tsukuba 305-8577, Japan
| | - Takanori Shinotsuka
- Department of Pharmacology School of Medicine, Keio University, 35 Shinanomachi, Tokyo 160-8582, Japan
| | - Masato Yasui
- Department of Pharmacology School of Medicine, Keio University, 35 Shinanomachi, Tokyo 160-8582, Japan
| | - Tatsuo Arai
- Graduate School of Pure and Applied Sciences and Tsukuba Research Center for Interdisciplinary Materials Science (TIMS), University of Tsukuba, Tsukuba 305-8577, Japan
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21
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Moorjani S. Miniaturized Technologies for Enhancement of Motor Plasticity. Front Bioeng Biotechnol 2016; 4:30. [PMID: 27148525 PMCID: PMC4834582 DOI: 10.3389/fbioe.2016.00030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 03/21/2016] [Indexed: 11/13/2022] Open
Abstract
The idea that the damaged brain can functionally reorganize itself – so when one part fails, there lies the possibility for another to substitute – is an exciting discovery of the twentieth century. We now know that motor circuits once presumed to be hardwired are not, and motor-skill learning, exercise, and even mental rehearsal of motor tasks can turn genes on or off to shape brain architecture, function, and, consequently, behavior. This is a very significant alteration from our previously static view of the brain and has profound implications for the rescue of function after a motor injury. Presentation of the right cues, applied in relevant spatiotemporal geometries, is required to awaken the dormant plastic forces essential for repair. The focus of this review is to highlight some of the recent progress in neural interfaces designed to harness motor plasticity, and the role of miniaturization in development of strategies that engage diverse elements of the neuronal machinery to synergistically facilitate recovery of function after motor damage.
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Affiliation(s)
- Samira Moorjani
- Department of Physiology and Biophysics, and the Washington National Primate Research Center, University of Washington , Seattle, WA , USA
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22
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López-Duarte I, Chairatana P, Wu Y, Pérez-Moreno J, Bennett PM, Reeve JE, Boczarow I, Kaluza W, Hosny NA, Stranks SD, Nicholas RJ, Clays K, Kuimova MK, Anderson HL. Thiophene-based dyes for probing membranes. Org Biomol Chem 2015; 13:3792-802. [PMID: 25703541 DOI: 10.1039/c4ob02507e] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We report the synthesis of four new cationic dipolar push–pull dyes, together with an evaluation of their photophysical and photobiological characteristics pertinent to imaging membranes by fluorescence and second harmonic generation (SHG). All four dyes consist of an N,N-diethylaniline electron-donor conjugated to a pyridinium electron-acceptor via a thiophene bridge, with either vinylene (–CH=CH–) or ethynylene (–C≡C–) linking groups, and with either singly-charged or doubly-charged pyridinium terminals. The absorption and fluorescence behavior of these dyes were compared to a commercially available fluorescent membrane stain, the styryl dye FM4-64. The hyperpolarizabilities of all dyes were compared using hyper-Rayleigh scattering at 800 nm. Cellular uptake, localization, toxicity and phototoxicity were evaluated using tissue cell cultures (HeLa, SK-OV-3 and MDA-231). Replacing the central alkene bridge of FM4-64 with a thiophene does not substantially change the absorption, fluorescence or hyperpolarizability, whereas changing the vinylene-links to ethynylenes shifts the absorption and fluorescence to shorter wavelengths, and reduces the hyperpolarizability by about a factor of two. SHG and fluorescence imaging experiments in live cells showed that the doubly-charged thiophene dyes localize in plasma membranes, and exhibit lower internalization rates compared to FM4-64, resulting in less signal from the cell cytosol. At a typical imaging concentration of 1 μM, the doubly-charged dyes showed no significant light or dark toxicity, whereas the singly-charged dyes are phototoxic even at 0.5 μM. The doubly-charged dyes showed phototoxicity at concentrations greater than 10 μM, although they do not generate singlet oxygen, indicating that the phototoxicity is type I rather than type II. The doubly-charged thiophene dyes are more effective than FM4-64 as SHG dyes for live cells.
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Affiliation(s)
- Ismael López-Duarte
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Oxford, UK OX1 3TA.
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23
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Allegra Mascaro AL, Sacconi L, Silvestri L, Knott G, Pavone FS. Multi-Modal Optical Imaging of the Cerebellum in Animals. THE CEREBELLUM 2015; 15:18-20. [PMID: 26476852 DOI: 10.1007/s12311-015-0730-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Thanks to their flexibility, optical techniques could be the key to explore anatomy, plasticity, and functionality of the cerebellum. As an example, an in vivo analysis of the dynamic remodeling of cerebellar axons by nonlinear microscopy can provide fundamental insights of the mechanism that promotes neuronal regeneration. Several studies showed that damaged climbing fibers are capable of regrowing also in adult animals. The investigation of the time-lapse dynamics of degeneration and regeneration of these axons within their complex environment can be performed by time-lapse two-photon fluorescence (TPF) imaging in vivo. Here, we show that single axonal branches can be dissected by laser axotomy, thus avoiding collateral damage to the adjacent dendrite and the formation of a persistent glial scar. Despite the very small denervated area, the injured axons consistently reshaped the connectivity with surrounding neurons and sprouted new branches through the intact surroundings. Correlative light and electron microscopy revealed that the sprouted branch contains large numbers of vesicles, with varicosities in the close vicinity of Purkinje dendrites. By using an RNA interference approach, we found that downregulating GAP-43 causes a significant increase in the turnover of presynaptic boutons and hampers the generation of reactive sprouts. Further, we report how nonlinear microscopy in combination with novel voltage sensitive dyes or transgenic mice allow optical registrations of action potential across a population of neurons opening promising prospective in understanding brain functionality. Finally, we describe novel implementations of light-sheet microscopy to resolve neuronal anatomy in whole cerebellum with cellular resolution. The understanding gained from these complementary optical methods may provide a deeper comprehension of the cerebellum.
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Affiliation(s)
- Anna Letizia Allegra Mascaro
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Via Nello Carrara 1, Sesto Fiorentino, 50019, Italy. .,National Research Council, National Institute of Optics, Largo Fermi 6, Florence, 50125, Italy.
| | - Leonardo Sacconi
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Via Nello Carrara 1, Sesto Fiorentino, 50019, Italy.,National Research Council, National Institute of Optics, Largo Fermi 6, Florence, 50125, Italy
| | - Ludovico Silvestri
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Via Nello Carrara 1, Sesto Fiorentino, 50019, Italy.,National Research Council, National Institute of Optics, Largo Fermi 6, Florence, 50125, Italy
| | - Graham Knott
- Ctr. Interdisciplinaire de Microscopie Electronique, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
| | - Francesco S Pavone
- European Laboratory for Non-Linear Spectroscopy, University of Florence, Via Nello Carrara 1, Sesto Fiorentino, 50019, Italy.,National Research Council, National Institute of Optics, Largo Fermi 6, Florence, 50125, Italy.,Department of Physics and Astronomy, University of Florence, Via Sansone 1, Sesto Fiorentino, 50019, Italy.,International Center for Computational Neurophotonics (ICON) Foundation, Via Nello Carrara 1, Sesto Fiorentino, 50019, Italy
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24
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Popovic MA, Carnevale N, Rozsa B, Zecevic D. Electrical behaviour of dendritic spines as revealed by voltage imaging. Nat Commun 2015; 6:8436. [PMID: 26436431 PMCID: PMC4594633 DOI: 10.1038/ncomms9436] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 08/20/2015] [Indexed: 12/23/2022] Open
Abstract
Thousands of dendritic spines on individual neurons process information and mediate plasticity by generating electrical input signals using a sophisticated assembly of transmitter receptors and voltage-sensitive ion channel molecules. Our understanding, however, of the electrical behaviour of spines is limited because it has not been possible to record input signals from these structures with adequate sensitivity and spatiotemporal resolution. Current interpretation of indirect data and speculations based on theoretical considerations are inconclusive. Here we use an electrochromic voltage-sensitive dye which acts as a transmembrane optical voltmeter with a linear scale to directly monitor electrical signals from individual spines on thin basal dendrites. The results show that synapses on these spines are not electrically isolated by the spine neck to a significant extent. Electrically, they behave as if they are located directly on dendrites.
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Affiliation(s)
- Marko A Popovic
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.,Institute for Multidisciplinary Research, Belgrade University, Belgrade 11030, Serbia
| | - Nicholas Carnevale
- Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Balazs Rozsa
- Institute of Experimental Medicine of the Hungarian Academy of Sciences, Budapest H-1083, Hungary.,The Faculty of Information Technology, Pázmány Péter University, Budapest H-1083, Hungary
| | - Dejan Zecevic
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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25
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Mishra A, Sahu S, Tripathi S, Krishnamoorthy G. Photoinduced intramolecular charge transfer in trans-2-[4'-(N,N-dimethylamino)styryl]imidazo[4,5-b]pyridine: effect of introducing a C[double bond, length as m-dash]C double bond. Photochem Photobiol Sci 2015; 13:1476-86. [PMID: 25103414 DOI: 10.1039/c4pp00237g] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The spectral characteristics of trans-2-[4'-(N,N-dimethylamino)styryl]imidazo[4,5-b]pyridine (t-DMASIP-b) have been investigated using absorption and fluorescence techniques, and compared with 2-(4'-N,N-dimethylamino)imidazo[4,5-b]pyridine (DMAPIP-b). The study reveals that introduction of a C[double bond, length as m-dash]C double bond strongly perturbs the photophysics of the system. Unlike DMAPIP-b, t-DMASIP-b emits a single emission in aprotic and protic solvents. The emission occurs from the locally excited state in nonpolar solvents and from a planar intramolecular charge transfer (PICT) state in polar solvents. Multiple linear regression analysis suggests that among the different solvent parameters, the dipolar interaction contributes more to the stabilization of the system in both the ground and excited states. Theoretical calculations suggest that, unlike in DMAPIP-b, proton coupled twisted intramolecular charge transfer (TICT) emission does not occur in t-DMASIP-b. The higher quantum yield obtained in the viscous solvent glycerol is attributed to the restriction of the twisting of the olefinic bond. The photoirradiation of t-DMASIP-b shows that isomerization takes place in all solvents, including viscous glycerol. The theoretically simulated potential energy surface shows that isomerization occurs via a phantom state, which is a nonradiative process. The rise in temperature favors the photoisomerization, thus, the fluorescence quantum yield decreases. The prototropic study indicates that, unlike in DMAPIP-b, the protonation takes place at different places to form the monocations.
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Affiliation(s)
- Anasuya Mishra
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, India.
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26
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Foust AJ, Zampini V, Tanese D, Papagiakoumou E, Emiliani V. Computer-generated holography enhances voltage dye fluorescence discrimination in adjacent neuronal structures. NEUROPHOTONICS 2015; 2:021007. [PMID: 26157998 PMCID: PMC4478842 DOI: 10.1117/1.nph.2.2.021007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/05/2014] [Indexed: 05/11/2023]
Abstract
Voltage-sensitive fluorescence indicators enable tracking neuronal electrical signals simultaneously in multiple neurons or neuronal subcompartments difficult to access with patch electrodes. However, efficient widefield epifluorescence detection of rapid voltage fluorescence transients necessitates that imaged cells and structures lie sufficiently far from other labeled structures to avoid contamination from out of focal plane and scattered light. We overcame this limitation by exciting dye fluorescence with one-photon computer-generated holography shapes contoured to axons or dendrites of interest, enabling widefield detection of voltage fluorescence with high spatial specificity. By shaping light onto neighboring axons and dendrites, we observed that dendritic back-propagating action potentials were broader and slowly rising compared with axonal action potentials, differences not measured in the same structures illuminated with a large "pseudowidefield" (pWF) spot of the same excitation density. Shaped illumination trials showed reduced baseline fluorescence, higher baseline noise, and fractional fluorescence transient amplitudes two times greater than trials acquired with pWF illumination of the same regions.
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Affiliation(s)
- Amanda J. Foust
- Paris Descartes University, Biomedical and Fundamental Science Faculty, Wavefront-Engineering Microscopy Group, Neurophotonics Laboratory, CNRS UMR8250, 45, rue des Saints Pères, 75270 Paris Cedex 06, France
| | - Valeria Zampini
- Paris Descartes University, Biomedical and Fundamental Science Faculty, Wavefront-Engineering Microscopy Group, Neurophotonics Laboratory, CNRS UMR8250, 45, rue des Saints Pères, 75270 Paris Cedex 06, France
| | - Dimitrii Tanese
- Paris Descartes University, Biomedical and Fundamental Science Faculty, Wavefront-Engineering Microscopy Group, Neurophotonics Laboratory, CNRS UMR8250, 45, rue des Saints Pères, 75270 Paris Cedex 06, France
| | - Eirini Papagiakoumou
- Paris Descartes University, Biomedical and Fundamental Science Faculty, Wavefront-Engineering Microscopy Group, Neurophotonics Laboratory, CNRS UMR8250, 45, rue des Saints Pères, 75270 Paris Cedex 06, France
- INSERM, 45, rue des Saints Pères, 75270 Paris Cedex 06, France
| | - Valentina Emiliani
- Paris Descartes University, Biomedical and Fundamental Science Faculty, Wavefront-Engineering Microscopy Group, Neurophotonics Laboratory, CNRS UMR8250, 45, rue des Saints Pères, 75270 Paris Cedex 06, France
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Loew LM, Lewis A. Second Harmonic Imaging of Membrane Potential. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 859:473-92. [PMID: 26238065 DOI: 10.1007/978-3-319-17641-3_19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The non-linear optical effect known as second harmonic generation (SHG) has been recognized since the earliest days of the laser. But it has only been in the last 20 years that it has begun to emerge as a viable microscope imaging contrast mechanism for visualization of cell and tissue structure and function. This is because only small modifications are required to equip a standard laser scanning 2-photon microscope for second harmonic imaging microscopy (SHIM). SHG signals from certain membrane-bound dyes are highly sensitive to membrane potential, indicating that SHIM may become a valuable probe of cell physiology. However, for the current generation of dyes and microscopes, the small signal size limits the number of photons that can be collected during the course of a fast action potential. Better dyes and optimized microscope optics could ultimately lead to the ability to image neuronal electrical activity with SHIM.
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Affiliation(s)
- Leslie M Loew
- Department of Cell Biology, R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT, 06030-1507, USA,
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Fisher JAN, Salzberg BM. Two-Photon Excitation of Fluorescent Voltage-Sensitive Dyes: Monitoring Membrane Potential in the Infrared. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 859:427-53. [PMID: 26238063 DOI: 10.1007/978-3-319-17641-3_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Functional imaging microscopy based on voltage-sensitive dyes (VSDs) has proven effective for revealing spatio-temporal patterns of activity in vivo and in vitro. Microscopy based on two-photon excitation of fluorescent VSDs offers the possibility of recording sub-millisecond membrane potential changes on micron length scales in cells that lie upwards of one millimeter below the brain's surface. Here we describe progress in monitoring membrane voltage using two-photon excitation (TPE) of VSD fluorescence, and detail an application of this emerging technology in which action potentials were recorded in single trials from individual mammalian nerve terminals in situ. Prospects for, and limitations of this method are reviewed.
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Loew LM. Design and Use of Organic Voltage Sensitive Dyes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 859:27-53. [PMID: 26238048 DOI: 10.1007/978-3-319-17641-3_2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The chemistry and the physics of voltage sensitive dyes (VSDs) should be understood and appreciated as a prerequisite for their optimal application to problems in neuroscience cardiology. This chapter provides a basic understanding of the properties of the large variety of available organic VSDs. The mechanisms by which the dyes respond to voltage guides the best set up of the optics for recording or imaging electrophysiological activity. The physical and chemical properties of the dyes can be tuned to optimize delivery to and staining of the cells in different experimental preparations. The aim of this chapter is to arm the experimentalists who use the dyes with enough information and data to be able to intelligently choose the best dye for their specific requirements.
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Affiliation(s)
- Leslie M Loew
- Department of Cell Biology, R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT, 06030-6406, USA,
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Imaging Submillisecond Membrane Potential Changes from Individual Regions of Single Axons, Dendrites and Spines. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 859:57-101. [PMID: 26238049 PMCID: PMC5671121 DOI: 10.1007/978-3-319-17641-3_3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A central question in neuronal network analysis is how the interaction between individual neurons produces behavior and behavioral modifications. This task depends critically on how exactly signals are integrated by individual nerve cells functioning as complex operational units. Regional electrical properties of branching neuronal processes which determine the input-output function of any neuron are extraordinarily complex, dynamic, and, in the general case, impossible to predict in the absence of detailed measurements. To obtain such a measurement one would, ideally, like to be able to monitor, at multiple sites, subthreshold events as they travel from the sites of origin (synaptic contacts on distal dendrites) and summate at particular locations to influence action potential initiation. It became possible recently to carry out this type of measurement using high-resolution multisite recording of membrane potential changes with intracellular voltage-sensitive dyes. This chapter reviews the development and foundation of the method of voltage-sensitive dye recording from individual neurons. Presently, this approach allows monitoring membrane potential transients from all parts of the dendritic tree as well as from axon collaterals and individual dendritic spines.
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Wilson SA, Millard A, Lewis A, Loew LM. Monitoring membrane potential with second-harmonic generation. Cold Spring Harb Protoc 2014; 2014:643-654. [PMID: 24890213 DOI: 10.1101/pdb.prot081786] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This protocol describes the nonlinear optical phenomenon known as second-harmonic generation (SHG) and discusses its special attributes for imaging membrane-potential changes in single cells and multicellular preparations. Undifferentiated N1E-115 mouse neuroblastoma cells are used as a model cellular system for membrane electrophysiology. Styryl and naphthylstyryl dyes, also known as hemicyanines, are a class of electrochromic membrane-staining probes that have been used to monitor membrane potential by fluorescence; they also produce SHG images of cell membranes with SHG intensities that are sensitive to voltage. These experiments allow for the precise characterization of the voltage sensitivity of SHG and identification of the optimal wavelength for the incident laser fundamental light. This protocol presents the steps for the culture, staining, patching, and imaging of cells. The details of the imaging system and the measurements obtained are discussed, as are the prospects of this technology for imaging membrane potential changes in neuronal preparations.
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Milne BF, Norman P, Nogueira F, Cardoso C. Marine natural products from the deep Pacific as potential non-linear optical chromophores. Phys Chem Chem Phys 2014; 15:14814-22. [PMID: 23907146 DOI: 10.1039/c3cp52528g] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Theoretical analysis using quadratic response theory within the time-dependent density functional theory (TDDFT) formalism shows that the dermacozines, a group of phenazine-based compounds isolated from cultures of Dermacoccus abyssi found in the Mariana Trench, possess large first hyperpolarisability (β) values at common incident laser wavelengths that are highly sensitive to the degree and type of substitution of the core structure. The phenazine moiety is a versatile and tunable chromophore for non-linear optics and this work serves to highlight the potential that (marine) natural products, even those found in the darkest places on the planet, may have for aiding developments in optical materials design.
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Affiliation(s)
- Bruce F Milne
- Centre for Computational Physics, Department of Physics, University of Coimbra, Rua Larga, 3004-516, Coimbra, Portugal.
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Crosignani V, Jahid S, Dvornikov AS, Gratton E. A deep tissue fluorescence imaging system with enhanced SHG detection capabilities. Microsc Res Tech 2014; 77:368-73. [PMID: 24610799 DOI: 10.1002/jemt.22354] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Revised: 02/21/2014] [Accepted: 02/23/2014] [Indexed: 11/05/2022]
Abstract
We describe a novel two-photon fluorescence microscopy system capable of producing high-quality second harmonic generation (SHG) images in thick turbid media by using an innovative detection system. This novel detection system is capable of detecting photons from a very large surface area. This system has proven effective in providing images of thick turbid samples, both biological and artificial. Due to its transmission detection geometry, the system is particularly suitable for detecting SHG signals, which are generally forward directed. In this article, we present comparative data acquired simultaneously on the same sample with the forward and epidetection schemes.
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Affiliation(s)
- Viera Crosignani
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California Irvine, Irvine, California, 92697
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34
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Toyota T, Banno T, Nitta S, Takinoue M, Nomoto T, Natsume Y, Matsumura S, Fujinami M. Molecular Building Blocks and Their Architecture in Biologically/Environmentally Compatible Soft Matter Chemical Machinery. J Oleo Sci 2014; 63:1085-98. [DOI: 10.5650/jos.ess14190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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35
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Nuriya M, Momotake A, Kimura Y, Yasui M, Kasai H, Arai T. Evaluation of Dialkylaminofluorene-Based Hemicyanine Dyes for Second Harmonic Generation Imaging by the Direct Comparison Approach. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2013. [DOI: 10.1246/bcsj.20130094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Mutsuo Nuriya
- Department of Pharmacology School of Medicine, Keio University
| | - Atsuya Momotake
- Graduate School of Pure and Applied Sciences, University of Tsukuba
| | - Yuta Kimura
- Graduate School of Pure and Applied Sciences, University of Tsukuba
| | - Masato Yasui
- Department of Pharmacology School of Medicine, Keio University
| | - Haruo Kasai
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo
| | - Tatsuo Arai
- Graduate School of Pure and Applied Sciences, University of Tsukuba
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36
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Reeve JE, Corbett AD, Boczarow I, Kaluza W, Barford W, Bayley H, Wilson T, Anderson HL. Porphyrins for Probing Electrical Potential Across Lipid Bilayer Membranes by Second Harmonic Generation. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201304515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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37
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Reeve JE, Corbett AD, Boczarow I, Kaluza W, Barford W, Bayley H, Wilson T, Anderson HL. Porphyrins for probing electrical potential across lipid bilayer membranes by second harmonic generation. Angew Chem Int Ed Engl 2013; 52:9044-8. [PMID: 23861287 PMCID: PMC3881515 DOI: 10.1002/anie.201304515] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Indexed: 11/08/2022]
Affiliation(s)
- James E Reeve
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
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38
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Tominaga T, Tominaga Y. A new nonscanning confocal microscopy module for functional voltage-sensitive dye and Ca2+ imaging of neuronal circuit activity. J Neurophysiol 2013; 110:553-61. [PMID: 23615547 DOI: 10.1152/jn.00856.2012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent advances in fluorescent confocal microscopy and voltage-sensitive and Ca(2+) dyes have vastly improved our ability to image neuronal circuits. However, existing confocal systems are not fast enough or too noisy for many live-cell functional imaging studies. Here, we describe and demonstrate the function of a novel, nonscanning confocal microscopy module. The optics, which are designed to fit the standard camera port of the Olympus BX51WI epifluorescent microscope, achieve a high signal-to-noise ratio (SNR) at high temporal resolution, making this configuration ideal for functional imaging of neuronal activities such as the voltage-sensitive dye (VSD) imaging. The optics employ fixed 100- × 100-pinhole arrays at the back focal plane (optical conjugation plane), above the tube lens of a usual upright microscope. The excitation light travels through these pinholes, and the fluorescence signal, emitted from subject, passes through corresponding pinholes before exciting the photodiodes of the imager: a 100- × 100-pixel metal-oxide semiconductor (MOS)-type pixel imager with each pixel corresponding to a single 100- × 100-μm photodiode. This design eliminated the need for a scanning device; therefore, acquisition rate of the imager (maximum rate of 10 kHz) is the only factor limiting acquisition speed. We tested the application of the system for VSD and Ca(2+) imaging of evoked neuronal responses on electrical stimuli in rat hippocampal slices. The results indicate that, at least for these applications, the new microscope maintains a high SNR at image acquisition rates of ≤0.3 ms per frame.
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Affiliation(s)
- Takashi Tominaga
- Laboratory for Neural Circuit Systems, Institute of Neuroscience, Tokushima Bunri University, Shido, Sanuki, Kagawa, Japan.
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39
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De Meulenaere E, Nguyen Bich N, de Wergifosse M, Van Hecke K, Van Meervelt L, Vanderleyden J, Champagne B, Clays K. Improving the second-order nonlinear optical response of fluorescent proteins: the symmetry argument. J Am Chem Soc 2013; 135:4061-9. [PMID: 23406416 DOI: 10.1021/ja400098b] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have successfully designed and expressed a new fluorescent protein with improved second-order nonlinear optical properties. It is the first time that a fluorescent protein has been rationally altered for this particular characteristic. On the basis of the specific noncentrosymmetry requirements for second-order nonlinear optical effects, we had hypothesized that the surprisingly low first hyperpolarizability (β) of the enhanced yellow fluorescent protein (eYFP) could be explained by centrosymmetric stacking of the chromophoric Tyr66 and the neighboring Tyr203 residue. The inversion center was removed by mutating Tyr203 into Phe203, with minor changes in the linear optical properties and even an improved fluorescence quantum yield. Structure determination by X-ray crystallography as well as linear optical characterization corroborate a correct folding and maturation. Measurement of β by means of hyper-Rayleigh scattering (HRS) as well as their analysis using quantum chemistry calculations validate our hypothesis. This observation can eventually lead to improved red fluorescent proteins for even better performance. On the basis of the specific function (second-harmonic generation), the color of its emission, and in analogy with the "fruit" names, we propose SHardonnay as the name for this Tyr203Phe mutant of eYFP.
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Affiliation(s)
- Evelien De Meulenaere
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, BE-3001 Leuven, Belgium
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40
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Popovic MA, Gao X, Carnevale NT, Zecevic D. Cortical dendritic spine heads are not electrically isolated by the spine neck from membrane potential signals in parent dendrites. Cereb Cortex 2012; 24:385-95. [PMID: 23054810 DOI: 10.1093/cercor/bhs320] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The evidence for an important hypothesis that cortical spine morphology might participate in modifying synaptic efficacy that underlies plasticity and possibly learning and memory mechanisms is inconclusive. Both theory and experiments suggest that the transfer of excitatory postsynaptic potential signals from spines to parent dendrites depends on the spine neck morphology and resistance. Furthermore, modeling of signal transfer in the opposite direction predicts that synapses on spine heads are not electrically isolated from voltages in the parent dendrite. In sharp contrast to this theoretical prediction, one of a very few measurements of electrical signals from spines reported that slow hyperpolarizing membrane potential changes are attenuated considerably by the spine neck as they spread from dendrites to synapses on spine heads. This result challenges our understanding of the electrical behavior of spines at a fundamental level. To re-examine the specific question of the transfer of dendritic signals to synapses of spines, we took advantage of a high-sensitivity Vm-imaging technique and carried out optical measurements of electrical signals from 4 groups of spines with different neck length and simultaneously from parent dendrites. The results show that spine neck does not filter membrane potential signals as they spread from the dendrites into the spine heads.
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41
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Surface functionalization of barium titanate SHG nanoprobes for in vivo imaging in zebrafish. Nat Protoc 2012; 7:1618-33. [PMID: 22899331 DOI: 10.1038/nprot.2012.087] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
To address the need for a bright, photostable labeling tool that allows long-term in vivo imaging in whole organisms, we recently introduced second harmonic generating (SHG) nanoprobes. Here we present a protocol for the preparation and use of a particular SHG nanoprobe label, barium titanate (BT), for in vivo imaging in living zebrafish embryos. Chemical treatment of the BT nanoparticles results in surface coating with amine-terminal groups, which act as a platform for a variety of chemical modifications for biological applications. Here we describe cross-linking of BT to a biotin-linked moiety using click chemistry methods and coating of BT with nonreactive poly(ethylene glycol) (PEG). We also provide details for injecting PEG-coated SHG nanoprobes into zygote-stage zebrafish embryos, and in vivo imaging of SHG nanoprobes during gastrulation and segmentation. Implementing the PROCEDURE requires a basic understanding of laser-scanning microscopy, experience with handling zebrafish embryos and chemistry laboratory experience. Functionalization of the SHG nanoprobes takes ∼3 d, whereas zebrafish preparation, injection and imaging setup should take approximately 2-4 h.
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42
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Fink AE, Bender KJ, Trussell LO, Otis TS, DiGregorio DA. Two-photon compatibility and single-voxel, single-trial detection of subthreshold neuronal activity by a two-component optical voltage sensor. PLoS One 2012; 7:e41434. [PMID: 22870221 PMCID: PMC3411718 DOI: 10.1371/journal.pone.0041434] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 06/27/2012] [Indexed: 11/29/2022] Open
Abstract
Minimally invasive measurements of neuronal activity are essential for understanding how signal processing is performed by neuronal networks. While optical strategies for making such measurements hold great promise, optical sensors generally lack the speed and sensitivity necessary to record neuronal activity on a single-trial, single-neuron basis. Here we present additional biophysical characterization and practical improvements of a two-component optical voltage sensor (2cVoS), comprised of the neuronal tracer dye, DiO, and dipicrylamine (DiO/DPA). Using laser spot illumination we demonstrate that membrane potential-dependent fluorescence changes can be obtained in a wide variety of cell types within brain slices. We show a correlation between membrane labeling and the sensitivity of the magnitude of fluorescence signal, such that neurons with the brightest membrane labeling yield the largest ΔF/F values per action potential (AP; ∼40%). By substituting a blue-shifted donor for DiO we confirm that DiO/DPA works, at least in part, via a Förster resonance energy transfer (FRET) mechanism. We also describe a straightforward iontophoretic method for labeling multiple neurons with DiO and show that DiO/DPA is compatible with two-photon (2P) imaging. Finally, exploiting the high sensitivity of DiO/DPA, we demonstrate AP-induced fluorescence transients (fAPs) recorded from single spines of hippocampal pyramidal neurons and single-trial measurements of subthreshold synaptic inputs to granule cell dendrites. Our findings suggest that the 2cVoS, DiO/DPA, enables optical measurements of trial-to-trial voltage fluctuations with very high spatial and temporal resolution, properties well suited for monitoring electrical signals from multiple neurons within intact neuronal networks.
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Affiliation(s)
- Ann E Fink
- Unit of Dynamic Neuronal Imaging, Department of Neuroscience, Paris, France
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43
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Vanzi F, Sacconi L, Cicchi R, Pavone FS. Protein conformation and molecular order probed by second-harmonic-generation microscopy. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:060901. [PMID: 22734730 DOI: 10.1117/1.jbo.17.6.060901] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Second-harmonic-generation (SHG) microscopy has emerged as a powerful tool to image unstained living tissues and probe their molecular and supramolecular organization. In this article, we review the physical basis of SHG, highlighting how coherent summation of second-harmonic response leads to the sensitivity of polarized SHG to the three-dimensional distribution of emitters within the focal volume. Based on the physical description of the process, we examine experimental applications for probing the molecular organization within a tissue and its alterations in response to different biomedically relevant conditions. We also describe the approach for obtaining information on molecular conformation based on SHG polarization anisotropy measurements and its application to the study of myosin conformation in different physiological states of muscle. The capability of coupling the advantages of nonlinear microscopy (micrometer-scale resolution in deep tissue) with tools for probing molecular structure in vivo renders SHG microscopy an extremely powerful tool for the advancement of biomedical optics, with particular regard to novel technologies for molecular diagnostic in vivo.
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Affiliation(s)
- Francesco Vanzi
- University of Florence, Department of Evolutionary Biology Leo Pardi, Florence, Italy
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44
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Dempsey WP, Fraser SE, Pantazis P. SHG nanoprobes: Advancing harmonic imaging in biology. Bioessays 2012; 34:351-60. [DOI: 10.1002/bies.201100106] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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45
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Pagès S, Côté D, De Koninck P. Optophysiological approach to resolve neuronal action potentials with high spatial and temporal resolution in cultured neurons. Front Cell Neurosci 2011; 5:20. [PMID: 22016723 PMCID: PMC3191737 DOI: 10.3389/fncel.2011.00020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 09/15/2011] [Indexed: 12/02/2022] Open
Abstract
Cell to cell communication in the central nervous system is encoded into transient and local membrane potential changes (ΔVm). Deciphering the rules that govern synaptic transmission and plasticity entails to be able to perform Vm recordings throughout the entire neuronal arborization. Classical electrophysiology is, in most cases, not able to do so within small and fragile neuronal subcompartments. Thus, optical techniques based on the use of fluorescent voltage-sensitive dyes (VSDs) have been developed. However, reporting spontaneous or small ΔVm from neuronal ramifications has been challenging, in part due to the limited sensitivity and phototoxicity of VSD-based optical measurements. Here we demonstrate the use of water soluble VSD, ANNINE-6plus, with laser-scanning microscopy to optically record ΔVm in cultured neurons. We show that the sensitivity (>10% of fluorescence change for 100 mV depolarization) and time response (sub millisecond) of the dye allows the robust detection of action potentials (APs) even without averaging, allowing the measurement of spontaneous neuronal firing patterns. In addition, we show that back-propagating APs can be recorded, along distinct dendritic sites and within dendritic spines. Importantly, our approach does not induce any detectable phototoxic effect on cultured neurons. This optophysiological approach provides a simple, minimally invasive, and versatile optical method to measure electrical activity in cultured neurons with high temporal (ms) resolution and high spatial (μm) resolution.
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Affiliation(s)
- Stéphane Pagès
- Centre de Recherche Université Laval Robert-Giffard, Université Laval Québec, QC, Canada
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46
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Cox G. Biological applications of second harmonic imaging. Biophys Rev 2011; 3:131. [PMID: 28510062 DOI: 10.1007/s12551-011-0052-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Accepted: 07/04/2011] [Indexed: 11/26/2022] Open
Abstract
Second Harmonic Generation (SHG) microscopy dates back to 1974, but effective biological use of the technique has a history of barely 10 years. It is now widely used to image collagen in many different applications, and is becoming useful for imaging myosin and some polysaccharides. A separate line on research has focussed on SHG dyes, which can provide high-speed indication of membrane potential and are now in use in neurobiology. This review looks at the progress to date in these different fields.
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Affiliation(s)
- Guy Cox
- Australian Centre for Microscopy and Microanalysis, University of Sydney, NSW, 2006, Australia.
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47
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Popovic MA, Foust AJ, McCormick DA, Zecevic D. The spatio-temporal characteristics of action potential initiation in layer 5 pyramidal neurons: a voltage imaging study. J Physiol 2011; 589:4167-87. [PMID: 21669974 DOI: 10.1113/jphysiol.2011.209015] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The spatial pattern of Na(+) channel clustering in the axon initial segment (AIS) plays a critical role in tuning neuronal computations, and changes in Na(+) channel distribution have been shown to mediate novel forms of neuronal plasticity in the axon. However, immunocytochemical data on channel distribution may not directly predict spatio-temporal characteristics of action potential initiation, and prior electrophysiological measures are either indirect (extracellular) or lack sufficient spatial resolution (intracellular) to directly characterize the spike trigger zone (TZ). We took advantage of a critical methodological improvement in the high sensitivity membrane potential imaging (V(m) imaging) technique to directly determine the location and length of the spike TZ as defined in functional terms. The results show that in mature axons of mouse cortical layer 5 pyramidal cells, action potentials initiate in a region ∼20 μm in length centred between 20 and 40 μm from the soma. From this region, the AP depolarizing wave invades initial nodes of Ranvier within a fraction of a millisecond and propagates in a saltatory fashion into axonal collaterals without failure at all physiologically relevant frequencies. We further demonstrate that, in contrast to the saltatory conduction in mature axons, AP propagation is non-saltatory (monotonic) in immature axons prior to myelination.
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Affiliation(s)
- Marko A Popovic
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, Department C/M Physiology, 333 Cedar Street, New Haven, CT, USA
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48
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Second-harmonic generation imaging of membrane potential with retinal analogues. Biophys J 2011; 100:232-42. [PMID: 21190676 DOI: 10.1016/j.bpj.2010.11.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/16/2010] [Accepted: 11/17/2010] [Indexed: 11/23/2022] Open
Abstract
Second-harmonic generation (SHG) by membrane-incorporated probes is a nonlinear optical signal that is voltage-sensitive and the basis of a sensitive method for imaging membrane potential. The voltage dependence of SHG by four different probes, three retinoids (all-trans retinal), and two new retinal analogs, 3-methyl-7-(4'-dimethylamino-phenyl)-2,4,6-heptatrienal (AR-3) and 3,7-dimethyl-9-(4'-dimethylamino-phenyl)-2,4,6,8-nonatetraenal (AR-4), and a styryl dye (FM4-64), were compared in HEK-293 cells. Results were analyzed by fitting data with an expression based on an electrooptic mechanism for SHG, which depends on the complex-valued first- and second-order nonlinear electric susceptibilities (χ² and χ³) of the probe. This gave values for the voltage sensitivity at the cell's resting potential, the voltage where the SHG is minimal, and the amplitude of the signal at that voltage for each of the four compounds. These measures show that χ² and χ³ are complex numbers for all compounds except all-trans retinal, consistent with the proximities of excitation and/or emission wavelengths to molecular resonances. Estimates of probe orientation and location in the membrane electric field show that, for the far-from-resonance case, the shot noise-limited signal/noise ratio depends on the location of the probe in the membrane, and on χ³ but not on χ².
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49
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Label-free live brain imaging and targeted patching with third-harmonic generation microscopy. Proc Natl Acad Sci U S A 2011; 108:5970-5. [PMID: 21444784 DOI: 10.1073/pnas.1018743108] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The ability to visualize neurons inside living brain tissue is a fundamental requirement in neuroscience and neurosurgery. Especially the development of a noninvasive probe of brain morphology with micrometer-scale resolution is highly desirable, as it would provide a noninvasive approach to optical biopsies in diagnostic medicine. Two-photon laser-scanning microscopy (2PLSM) is a powerful tool in this regard, and has become the standard for minimally invasive high-resolution imaging of living biological samples. However, while 2PLSM-based optical methods provide sufficient resolution, they have been hampered by the requirement for fluorescent dyes to provide image contrast. Here we demonstrate high-contrast imaging of live brain tissue at cellular resolution, without the need for fluorescent probes, using optical third-harmonic generation (THG). We exploit the specific geometry and lipid content of brain tissue at the cellular level to achieve partial phase matching of THG, providing an alternative contrast mechanism to fluorescence. We find that THG brain imaging allows rapid, noninvasive label-free imaging of neurons, white-matter structures, and blood vessels simultaneously. Furthermore, we exploit THG-based imaging to guide micropipettes towards designated neurons inside live tissue. This work is a major step towards label-free microscopic live brain imaging, and opens up possibilities for the development of laser-guided microsurgery techniques in the living brain.
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Abstract
In the last decades, imaging membrane potential has become a fruitful approach to study neural circuits, especially in invertebrate preparations with large, resilient neurons. At the same time, particularly in mammalian preparations, voltage imaging methods suffer from poor signal to noise and secondary side effects, and they fall short of providing single-cell resolution when imaging of the activity of neuronal populations. As an introduction to these techniques, we briefly review different voltage imaging methods (including organic fluorophores, SHG chromophores, genetic indicators, hybrid, nanoparticles, and intrinsic approaches) and illustrate some of their applications to neuronal biophysics and mammalian circuit analysis. We discuss their mechanisms of voltage sensitivity, from reorientation, electrochromic, or electro-optical phenomena to interaction among chromophores or membrane scattering, and highlight their advantages and shortcomings, commenting on the outlook for development of novel voltage imaging methods.
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Affiliation(s)
- Darcy S Peterka
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
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