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Chen S, Liu Z, Li B, Hou Y, Peng Y, Li J, Yuan Q, Gan W. Probing the structural evolution on the surface of cardiolipin vesicles with an amphiphilic second harmonic generation and fluorescence probe. J Chem Phys 2024; 161:014705. [PMID: 38949588 DOI: 10.1063/5.0211845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 06/15/2024] [Indexed: 07/02/2024] Open
Abstract
Investigating the influence of the ambient chemical environment on molecular behaviors in liposomes is crucial for understanding and manipulating cellular vitality as well as the capabilities of lipid drug carriers in various environments. Here, we designed and synthesized a second harmonic generation (SHG) and fluorescence probe molecule called Pyr-Py+-N+ (PPN), which possesses membrane-targeting capability. We employed PPN to investigate the response of lipid vesicles composed of cardiolipin to the presence of exogenous salt. The kinetic behaviors, including the adsorption and embedding of PPN on the surface of small unilamellar vesicles (SUVs) composed of cardiolipin, were analyzed. The response of the SUVs to the addition of NaCl was also monitored. A rapid decrease in vesicle size can be evidenced through the rapid drop in SHG emission originating from PPN located on the vesicle surface.
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Affiliation(s)
- Shujiao Chen
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China and School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
| | - Zhongcheng Liu
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Bifei Li
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China and School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
| | - Yi Hou
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China and School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
| | - Yingying Peng
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China and School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
| | - Jianhui Li
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China and School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
| | - Qunhui Yuan
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, School of Materials Science and Engineering, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China
| | - Wei Gan
- Shenzhen Key Laboratory of Flexible Printed Electronics Technology, School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China and School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
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2
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Oliden-Sánchez A, Sola-Llano R, Pérez-Pariente J, Gómez-Hortigüela L, Martínez-Martínez V. Confinement of a Styryl Dye into Nanoporous Aluminophosphates: Channels vs. Cavities. Int J Mol Sci 2024; 25:3577. [PMID: 38612388 PMCID: PMC11011965 DOI: 10.3390/ijms25073577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/07/2024] [Accepted: 03/13/2024] [Indexed: 04/14/2024] Open
Abstract
Styryl dyes are generally poor fluorescent molecules inherited from their flexible molecular structures. However, their emissive properties can be boosted by restricting their molecular motions. A tight confinement into inorganic molecular sieves is a good strategy to yield highly fluorescent hybrid systems. In this work, we compare the confinement effect of two Mg-aluminophosphate zeotypes with distinct pore systems (the AEL framework, a one-dimensional channeled structure with elliptical pores of 6.5 Å × 4.0 Å, and the CHA framework, composed of large cavities of 6.7 Å × 10.0 Å connected by eight-ring narrower windows) for the encapsulation of 4-DASPI styryl dye (trans-4-[4-(Dimethylamino)styryl]-1-methylpyridinium iodide). The resultant hybrid systems display significantly improved photophysical features compared to 4-DASPI in solution as a result of tight confinement in both host inorganic frameworks. Molecular simulations reveal a tighter confinement of 4-DASPI in the elliptical channels of AEL, explaining its excellent photophysical properties. On the other hand, a singular arrangement of 4-DASPI dye is found when confined within the cavity-based CHA framework, where the 4-DASPI molecule spans along two adjacent cavities, with each aromatic ring sitting on these adjacent cavities and the polymethine chain residing within the narrower eight-ring window. However, despite the singularity of this host-guest arrangement, it provides less tight confinement for 4-DASPI than AEL, resulting in a slightly lower quantum yield.
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Affiliation(s)
- Ainhoa Oliden-Sánchez
- Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apartado 644, 48080 Bilbao, Spain; (A.O.-S.); (R.S.-L.)
| | - Rebeca Sola-Llano
- Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apartado 644, 48080 Bilbao, Spain; (A.O.-S.); (R.S.-L.)
| | - Joaquín Pérez-Pariente
- Instituto de Catálisis y Petroleoquímica (CSIC), c/Marie Curie 2, Cantoblanco, 28049 Madrid, Spain;
| | - Luis Gómez-Hortigüela
- Instituto de Catálisis y Petroleoquímica (CSIC), c/Marie Curie 2, Cantoblanco, 28049 Madrid, Spain;
| | - Virginia Martínez-Martínez
- Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apartado 644, 48080 Bilbao, Spain; (A.O.-S.); (R.S.-L.)
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3
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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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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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5
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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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6
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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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Woodford CR, Frady EP, Smith RS, Morey B, Canzi G, Palida SF, Araneda RC, Kristan WB, Kubiak CP, Miller EW, Tsien RY. Improved PeT molecules for optically sensing voltage in neurons. J Am Chem Soc 2015; 137:1817-24. [PMID: 25584688 DOI: 10.1021/ja510602z] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
VoltageFluor (VF) dyes have the potential to measure voltage optically in excitable membranes with a combination of high spatial and temporal resolution essential to better characterize the voltage dynamics of large groups of excitable cells. VF dyes sense voltage with high speed and sensitivity using photoinduced electron transfer (PeT) through a conjugated molecular wire. We show that tuning the driving force for PeT (ΔGPeT + w) through systematic chemical substitution modulates voltage sensitivity, estimate (ΔGPeT + w) values from experimentally measured redox potentials, and validate the voltage sensitivities in patch-clamped HEK cells for 10 new VF dyes. VF2.1(OMe).H, with a 48% ΔF/F per 100 mV, shows approximately 2-fold improvement over previous dyes in HEK cells, dissociated rat cortical neurons, and medicinal leech ganglia. Additionally, VF2.1(OMe).H faithfully reports pharmacological effects and circuit activity in mouse olfactory bulb slices, thus opening a wide range of previously inaccessible applications for voltage-sensitive dyes.
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Affiliation(s)
- Clifford R Woodford
- Departments of Chemistry and Biochemistry, ‡Pharmacology, §Neurosciences Graduate Group, ∥Division of Biological Sciences, ⊥Biomedical Sciences, and #Howard Hughes Medical Institute, University of California, San Diego , La Jolla, California 92093, United States
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8
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Tropcheva R, Lesev N, Danova S, Stoitsova S, Kaloyanova S. Novel cyanine dyes and homodimeric styryl dyes as fluorescent probes for assessment of lactic acid bacteria cell viability. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 143:120-9. [PMID: 25618816 DOI: 10.1016/j.jphotobiol.2015.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 12/26/2014] [Accepted: 01/03/2015] [Indexed: 11/28/2022]
Abstract
Innovations in labeling techniques and in the design and synthesis of dye structures are closely related to the development of service equipment such as light sources and detection methods. Novel styryl homodimers and monomethine cyanine dyes were synthesized and their staining abilities for discrimination between live and dead lactic acid bacterial cells were investigated. The dyes were combined in pairs based on their excitation and emission maxima and the capacity to penetrate through cell membranes of viable bacterial cells. The absorption maxima in the same region and the large Stocks shifts of the styryl derivatives allowed viability analysis to be done with epifluorescent microscope with a very basic configuration - one light source about 480nm and one filter for the fluorescent emissions. A staining protocol was developed and applied for live/dead analysis of Bulgarian yoghurt starters. The live cells quantification by the fluorescence dyes coincided well with the results of the much more time-consuming tests by plate counting. Thus, the proposed dye combinations are appropriate for rapid viability estimation in small laboratories that may have conventional equipment.
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Affiliation(s)
- Rositsa Tropcheva
- The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Nedyalko Lesev
- Faculty of Chemistry and Pharmacy, University of Sofia, 1 James Bourchier Ave., 1164 Sofia, Bulgaria
| | - Svetla Danova
- The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Stoyanka Stoitsova
- The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Stefka Kaloyanova
- Faculty of Chemistry and Pharmacy, University of Sofia, 1 James Bourchier Ave., 1164 Sofia, Bulgaria.
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9
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Grosjean K, Mongrand S, Beney L, Simon-Plas F, Gerbeau-Pissot P. Differential effect of plant lipids on membrane organization: specificities of phytosphingolipids and phytosterols. J Biol Chem 2015; 290:5810-25. [PMID: 25575593 DOI: 10.1074/jbc.m114.598805] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The high diversity of the plant lipid mixture raises the question of their respective involvement in the definition of membrane organization. This is particularly the case for plant plasma membrane, which is enriched in specific lipids, such as free and conjugated forms of phytosterols and typical phytosphingolipids, such as glycosylinositolphosphoceramides. This question was here addressed extensively by characterizing the order level of membrane from vesicles prepared using various plant lipid mixtures and labeled with an environment-sensitive probe. Fluorescence spectroscopy experiments showed that among major phytosterols, campesterol exhibits a stronger ability than β-sitosterol and stigmasterol to order model membranes. Multispectral confocal microscopy, allowing spatial analysis of membrane organization, demonstrated accordingly the strong ability of campesterol to promote ordered domain formation and to organize their spatial distribution at the membrane surface. Conjugated sterol forms, alone and in synergy with free sterols, exhibit a striking ability to order membrane. Plant sphingolipids, particularly glycosylinositolphosphoceramides, enhanced the sterol-induced ordering effect, emphasizing the formation and increasing the size of sterol-dependent ordered domains. Altogether, our results support a differential involvement of free and conjugated phytosterols in the formation of ordered domains and suggest that the diversity of plant lipids, allowing various local combinations of lipid species, could be a major contributor to membrane organization in particular through the formation of sphingolipid-sterol interacting domains.
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Affiliation(s)
- Kevin Grosjean
- From UMR1347 Agroécologie, ERL 6300 CNRS, Université de Bourgogne, 17 Rue Sully, BP 86510, 21065 Dijon Cedex, France
| | - Sébastien Mongrand
- the Laboratoire de Biogenèse Membranaire (LBM), CNRS, UMR 5200, F-33000 Villenave d'Ornon, France, the Laboratoire de Biogenèse Membranaire (LBM), Université de Bordeaux, UMR 5200, F-33000 Villenave d'Ornon, France
| | - Laurent Beney
- the Laboratoire Procédés Alimentaires et Microbiologiques, AgroSup Dijon, F-21000 Dijon, France, and
| | - Françoise Simon-Plas
- ERL 6300 CNRS, INRA, UMR1347 Agroécologie, 17 Rue Sully, BP 86510, 21065 Dijon Cedex, France
| | - Patricia Gerbeau-Pissot
- From UMR1347 Agroécologie, ERL 6300 CNRS, Université de Bourgogne, 17 Rue Sully, BP 86510, 21065 Dijon Cedex, France,
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10
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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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11
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Demchenko AP, Duportail G, Oncul S, Klymchenko AS, Mély Y. Introduction to fluorescence probing of biological membranes. Methods Mol Biol 2015; 1232:19-43. [PMID: 25331125 DOI: 10.1007/978-1-4939-1752-5_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Fluorescence is one of the most powerful and commonly used tools in biophysical studies of biomembrane structure and dynamics that can be applied on different levels, from lipid monolayers and bilayers to living cells, tissues, and whole animals. Successful application of this method relies on proper design of fluorescence probes with optimized photophysical properties. These probes are efficient for studying the microscopic analogs of viscosity, polarity, and hydration, as well as the molecular order, environment relaxation, and electrostatic potentials at the sites of their location. Being smaller than the membrane width they can sense the gradients of these parameters across the membrane. We present examples of novel dyes that achieve increased spatial resolution and information content of the probe responses. In this respect, multiparametric environment-sensitive probes feature considerable promise.
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Affiliation(s)
- Alexander P Demchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kiev, 01030, Ukraine,
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12
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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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14
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Jinno Y, Shoda K, Rial-Verde E, Yuste R, Miyawaki A, Tsutsui H. Engineering a genetically-encoded SHG chromophore by electrostatic targeting to the membrane. Front Mol Neurosci 2014; 7:93. [PMID: 25505870 PMCID: PMC4245886 DOI: 10.3389/fnmol.2014.00093] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 11/08/2014] [Indexed: 11/22/2022] Open
Abstract
Although second harmonic generation (SHG) microscopy provides unique imaging advantages for voltage imaging and other biological applications, genetically-encoded SHG chromophores remain relatively unexplored. SHG only arises from non-centrosymmetric media, so an anisotropic arrangement of chromophores is essential to provide strong SHG signals. Here, inspired by the mechanism by which K-Ras4B associates with plasma membranes, we sought to achieve asymmetric arrangements of chromophores at the membrane-cytoplasm interface using the fluorescent protein mVenus. After adding a farnesylation motif to the C-terminus of mVenus, nine amino acids composing its β-barrel surface were replaced by lysine, forming an electrostatic patch. This protein (mVe9Knus-CVIM) was efficiently targeted to the plasma membrane in a geometrically defined manner and exhibited SHG in HEK293 cells. In agreement with its design, mVe9Knus-CVIM hyperpolarizability was oriented at a small angle (~7.3°) from the membrane normal. Genetically-encoded SHG chromophores could serve as a molecular platform for imaging membrane potential.
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Affiliation(s)
- Yuka Jinno
- Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University Suita, Japan
| | - Keiko Shoda
- Laboratory for Cell Function Dynamics, Brain Science Institute, RIKEN Wako, Japan
| | - Emiliano Rial-Verde
- Department of Biological Sciences, Neurotechnology Center, Columbia University New York, NY, USA
| | - Rafael Yuste
- Department of Biological Sciences, Neurotechnology Center, Columbia University New York, NY, USA
| | - Atsushi Miyawaki
- Laboratory for Cell Function Dynamics, Brain Science Institute, RIKEN Wako, Japan
| | - Hidekazu Tsutsui
- Laboratory for Cell Function Dynamics, Brain Science Institute, RIKEN Wako, Japan ; Formation of and Information Processing by Neural Networks, and Control, PRESTO, Japan Science and Technology Agency (JST) Kawaguchi, Japan ; Department of Material Science, Japan Advanced Institute of Science and Technology Nomi, Japan
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15
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Blake HL, Robinson D. QM/MM studies of contemporary and novel membrane raft fluorescent probes. Molecules 2014; 19:10230-41. [PMID: 25029071 PMCID: PMC6271554 DOI: 10.3390/molecules190710230] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 07/09/2014] [Accepted: 07/10/2014] [Indexed: 11/22/2022] Open
Abstract
We have studied a number of contemporary and novel membrane probes, selected for their structural similarity to membrane raft components, in order to properly anchor themselves within a sphingolipid/cholesterol rich region. A QM/MM approach was adopted in order to understand the structural and electrostatic influences of fluorescence emission shifts of the probes in different lipid and solvation environments. The proposed modifications to the membrane probes have shown encouraging data relating not only to emission shifts within the membrane, but also their ability to anchor within a membrane raft domain and the stability to internalization within a membrane system.
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Affiliation(s)
- Hannah L Blake
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - David Robinson
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
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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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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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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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19
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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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20
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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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21
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Lien CH, Tilbury K, Chen SJ, Campagnola PJ. Precise, motion-free polarization control in Second Harmonic Generation microscopy using a liquid crystal modulator in the infinity space. BIOMEDICAL OPTICS EXPRESS 2013; 4:1991-2002. [PMID: 24156059 PMCID: PMC3799661 DOI: 10.1364/boe.4.001991] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 08/22/2013] [Accepted: 08/23/2013] [Indexed: 05/02/2023]
Abstract
Second Harmonic Generation (SHG) microscopy coupled with polarization analysis has great potential for use in tissue characterization, as molecular and supramolecular structural details can be extracted. Such measurements are difficult to perform quickly and accurately. Here we present a new method that uses a liquid crystal modulator (LCM) located in the infinity space of a SHG laser scanning microscope that allows the generation of any desired linear or circular polarization state. As the device contains no moving parts, polarization can be rotated accurately and faster than by manual or motorized control. The performance in terms of polarization purity was validated using Stokes vector polarimetry, and found to have minimal residual polarization ellipticity. SHG polarization imaging characteristics were validated against well-characterized specimens having cylindrical and/or linear symmetries. The LCM has a small footprint and can be implemented easily in any standard microscope and is cost effective relative to other technologies.
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Affiliation(s)
- Chi-Hsiang Lien
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan
| | - Karissa Tilbury
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Shean-Jen Chen
- Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan
| | - Paul J. Campagnola
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- Medical Physics Department, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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22
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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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23
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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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24
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Demchenko AP. Modern views on the structure and dynamics of biological membranes. ACTA ACUST UNITED AC 2012. [DOI: 10.7124/bc.000029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- A. P. Demchenko
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine
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25
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Klymchenko AS, Duportail G, Mély Y. 3-Hydroxychromone Probes Precisely Located and Oriented in Lipid Bilayers: A Toolkit for Biomembrane Research. SPRINGER SERIES ON FLUORESCENCE 2012. [DOI: 10.1007/4243_2012_44] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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26
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In vivo imaging of myelin in the vertebrate central nervous system using third harmonic generation microscopy. Biophys J 2011; 100:1362-71. [PMID: 21354410 DOI: 10.1016/j.bpj.2011.01.031] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Accepted: 01/13/2011] [Indexed: 11/18/2022] Open
Abstract
Loss of myelin in the central nervous system (CNS) leads to debilitating neurological deficits. High-resolution optical imaging of myelin in the CNS of animal models is limited by a lack of in vivo myelin labeling strategies. We demonstrated that third harmonic generation (THG) microscopy-a coherent, nonlinear, dye-free imaging modality-provides micrometer resolution imaging of myelin in the mouse CNS. In fixed tissue, we found that THG signals arose from white matter tracts and were colocalized with two-photon excited fluorescence (2PEF) from a myelin-specific dye. In vivo, we used simultaneous THG and 2PEF imaging of the mouse spinal cord to resolve myelin sheaths surrounding individual fluorescently-labeled axons, and followed myelin disruption after spinal cord injury. Finally, we suggest optical mechanisms that underlie the myelin specificity of THG. These results establish THG microscopy as an ideal tool for the study of myelin loss and recovery.
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27
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Robinson D, Besley NA, O’Shea P, Hirst JD. Di-8-ANEPPS Emission Spectra in Phospholipid/Cholesterol Membranes: A Theoretical Study. J Phys Chem B 2011; 115:4160-7. [DOI: 10.1021/jp1111372] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David Robinson
- School of Chemistry and ‡School of Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Nicholas A. Besley
- School of Chemistry and ‡School of Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Paul O’Shea
- School of Chemistry and ‡School of Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Jonathan D. Hirst
- School of Chemistry and ‡School of Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
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28
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Przybylo M, Borowik T, Langner M. Fluorescence Techniques for Determination of the Membrane Potentials in High Throughput Screening. J Fluoresc 2010; 20:1139-57. [DOI: 10.1007/s10895-010-0665-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 04/05/2010] [Indexed: 01/14/2023]
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29
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Reeve JE, Anderson HL, Clays K. Dyes for biological second harmonic generation imaging. Phys Chem Chem Phys 2010; 12:13484-98. [DOI: 10.1039/c003720f] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Barsu C, Cheaib R, Chambert S, Queneau Y, Maury O, Cottet D, Wege H, Douady J, Bretonnière Y, Andraud C. Neutral push-pull chromophores for nonlinear optical imaging of cell membranes. Org Biomol Chem 2010; 8:142-50. [DOI: 10.1039/b915654b] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Sundelacruz S, Levin M, Kaplan DL. Role of membrane potential in the regulation of cell proliferation and differentiation. Stem Cell Rev Rep 2009; 5:231-46. [PMID: 19562527 PMCID: PMC10467564 DOI: 10.1007/s12015-009-9080-2] [Citation(s) in RCA: 325] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 06/07/2009] [Indexed: 12/11/2022]
Abstract
Biophysical signaling, an integral regulator of long-term cell behavior in both excitable and non-excitable cell types, offers enormous potential for modulation of important cell functions. Of particular interest to current regenerative medicine efforts, we review several examples that support the functional role of transmembrane potential (V(mem)) in the regulation of proliferation and differentiation. Interestingly, distinct V(mem) controls are found in many cancer cell and precursor cell systems, which are known for their proliferative and differentiation capacities, respectively. Collectively, the data demonstrate that bioelectric properties can serve as markers for cell characterization and can control cell mitotic activity, cell cycle progression, and differentiation. The ability to control cell functions by modulating bioelectric properties such as V(mem) would be an invaluable tool for directing stem cell behavior toward therapeutic goals. Biophysical properties of stem cells have only recently begun to be studied and are thus in need of further characterization. Understanding the molecular and mechanistic basis of biophysical regulation will point the way toward novel ways to rationally direct cell functions, allowing us to capitalize upon the potential of biophysical signaling for regenerative medicine and tissue engineering.
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Affiliation(s)
- Sarah Sundelacruz
- Department of Biomedical Engineering, Tufts University, 4 Colby St., Medford, MA 02155, USA
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32
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Demchenko AP, Mély Y, Duportail G, Klymchenko AS. Monitoring biophysical properties of lipid membranes by environment-sensitive fluorescent probes. Biophys J 2009; 96:3461-70. [PMID: 19413953 DOI: 10.1016/j.bpj.2009.02.012] [Citation(s) in RCA: 301] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 02/11/2009] [Accepted: 02/17/2009] [Indexed: 01/21/2023] Open
Abstract
We review the main trends in the development of fluorescence probes to obtain information about the structure, dynamics, and interactions in biomembranes. These probes are efficient for studying the microscopic analogs of viscosity, polarity, and hydration, as well as the molecular order, environment relaxation, and electrostatic potentials at the sites of their location. Progress is being made in increasing the information content and spatial resolution of the probe responses. Multichannel environment-sensitive probes that can distinguish between different membrane physicochemical properties through multiple spectroscopic parameters show considerable promise.
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33
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Scherschel JA, Rubart M. Cardiovascular imaging using two-photon microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2008; 14:492-506. [PMID: 18986603 PMCID: PMC2583458 DOI: 10.1017/s1431927608080835] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Two-photon excitation microscopy has become the standard technique for high resolution deep tissue and intravital imaging. It provides intrinsic three-dimensional resolution in combination with increased penetration depth compared to single-photon confocal microscopy. This article will describe the basic physical principles of two-photon excitation and will review its multiple applications to cardiovascular imaging, including second harmonic generation and fluorescence laser scanning microscopy. In particular, the capability and limitations of multiphoton microscopy to assess functional heterogeneity on a cellular scale deep within intact, Langendorff-perfused hearts are demonstrated. It will also discuss the use of two-photon excitation-induced release of caged compounds for the study of intracellular calcium signaling and intercellular dye transfer.
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Affiliation(s)
- John A Scherschel
- Department of Pediatrics, Division of Cardiology, Wells Center for Pediatric Research, 1044 West Walnut Street, Indianapolis, IN 46202, USA
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34
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Yan P, Xie A, Wei M, Loew LM. Amino(oligo)thiophene-based environmentally sensitive biomembrane chromophores. J Org Chem 2008; 73:6587-94. [PMID: 18665648 DOI: 10.1021/jo800852h] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
There is a growing need for cellular imaging with fluorescent probes that emit at longer wavelengths to minimize the effects of absorption, autofluorescence, and scattering from biological tissue. In this paper a series of new environmentally sensitive hemicyanine dyes featuring amino(oligo)thiophene donors have been synthesized via aldol condensation between a 4-methylpyridinium salt and various amino(oligo)thiophene carboxaldehydes, which were, in turn, obtained from amination of bromo(oligo)thiophene carboxaldehyde. Side chains on these fluorophores impart a strong affinity for biological membranes. Compared with benzene analogues, these thiophene fluorophores show significant red shift in the absorption and emission spectra, offering compact red and near-infrared emitting fluorophores. More importantly, both the fluorescence quantum yields and the emission peaks are very sensitive to various environmental factors such as solvent polarity or viscosity, membrane potential, and membrane composition. These chromophores also exhibit strong nonlinear optical properties, including two-photon fluorescence and second harmonic generation, which are themselves environmentally sensitive. The combination of long wavelength fluorescence and nonlinear optical properties make these chromophores very suitable for applications that require sensing or imaging deep inside tissues.
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Affiliation(s)
- Ping Yan
- Richard D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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35
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Friedl P, Wolf K, von Andrian UH, Harms G. Biological second and third harmonic generation microscopy. ACTA ACUST UNITED AC 2008; Chapter 4:Unit 4.15. [PMID: 18228516 DOI: 10.1002/0471143030.cb0415s34] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Multiphoton microscopy has become a standard method for noninvasive imaging of thick specimens with subcellular resolution. Higher harmonic generation microscopy (HHGM), based on nonlinear multiphoton excitation, is a contrast mechanism for the structural and molecular imaging of native samples in cell culture and in fixed and live tissues, for both, three-dimensional and four-dimensional reconstructions. HHGM comprises second and third harmonic generation (SHG, THG) of ordered molecules, can be obtained without exogenous labels, and provides detailed real-time optical reconstruction of fibrillar collagen, myosin, microtubules, and membrane potential, as well as cell depolarization. This unit presents the principles of SHG and THG and the basic setup of a HHGM system, and summarizes current applications in cell biology. Multimodal multiphoton microscopy using HHGM together with two-photon excited fluorescence will develop into a key approach to real-time imaging of cell dynamics in the context of live tissues.
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36
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Rusu CF, Lanig H, Othersen OG, Kryschi C, Clark T. Monitoring Biological Membrane-Potential Changes: A CI QM/MM Study. J Phys Chem B 2008; 112:2445-55. [DOI: 10.1021/jp075372+] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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37
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Teisseyre TZ, Millard AC, Yan P, Wuskell JP, Wei MD, Lewis A, Loew LM. Nonlinear optical potentiometric dyes optimized for imaging with 1064-nm light. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:044001. [PMID: 17867805 DOI: 10.1117/1.2772276] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Nonlinear optical phenomena, such as two-photon fluorescence (2PF) and second harmonic generation (SHG), in combination with voltage sensitive dyes, can be used to acquire high-resolution spatio temporal maps of electrical activity in excitable cells and tissue. Developments in 1064-nm fiber laser technology have simplified the generation of high-intensity, long-wavelength, femtosecond light pulses, capable of penetrating deep into tissue. To merge these two advances requires the design and synthesis of new dyes that are optimized for longer wavelengths and that produce fast and sensitive responses to membrane potential changes. In this work, we have systematically screened a series of new dyes with varying chromophores and sidechains that anchor them in cell membranes. We discovered several dyes that could potentially be used for in vivo measurements of cellular electrical activity because of their rapid and sensitive responses to membrane potential. Some of these dyes show optimal activity for SHG; others for 2PF. This regulated approach to dye screening also allows significant insight into the molecular mechanisms behind both SHG and 2PF. In particular, the differing patterns of sensitivity and kinetics for these two nonlinear optical modalities indicate that their voltage sensitivity originates from differing mechanisms.
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Affiliation(s)
- Thomas Z Teisseyre
- University of Connecticut Health Center, Richard D. Berlin Center for Cell Analysis and Modeling, 263 Farmington Avenue, MC-1507, Farmington, Connecticut 06030-1507, USA
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38
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Vercillo NC, Herald KJ, Fox JM, Der BS, Dattelbaum JD. Analysis of ligand binding to a ribose biosensor using site-directed mutagenesis and fluorescence spectroscopy. Protein Sci 2007; 16:362-8. [PMID: 17242374 PMCID: PMC2203328 DOI: 10.1110/ps.062595707] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Computational design of proteins with altered ligand specificity is an emerging method for the creation of new biosensing systems. In this work, we investigated the outcome of site-directed mutagenesis on the Escherichia coli ribose binding protein (RBP), which is frequently used as a design scaffold for computational searches. A ribose biosensor was first constructed whereby an environmentally sensitive fluorescent probe was covalently attached to RBP at position S265C. This protein conjugate displayed a 54% decrease in emission intensity upon the addition of saturating ribose concentrations and exhibited an apparent dissociation constant (K(d) ) of 3.4 microM. Site-directed mutants within the RBP binding pocket were created and examined for ribose binding ability and overall structural stability. Because as many as 12 mutations are needed to alter ligand specificity in RBP, we measured the effect of single and multiple alanine mutations on stability and signal transduction potential of the ribose biosensor. Single alanine mutations had significant impact on both stability and signaling. Mutations of N190A and F214A each produced melting temperatures >8 degrees C below those observed for the wild-type protein. Residue Q235, located in the hinge region of RBP, appeared to be a hot spot for global protein stability as well. Additional single alanine mutations demonstrated as much as 200-fold increase in apparent K(d) but retained overall protein stability. The data collected from this study may be incorporated into design algorithms to help create more stable biosensors and optimize signal transduction properties for a variety of important analytes.
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Affiliation(s)
- Natalie C Vercillo
- Department of Chemistry, University of Richmond, Gottwald Center for Sciences, Richmond, Virginia 23173, USA
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39
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Stuart GJ, Palmer LM. Imaging membrane potential in dendrites and axons of single neurons. Pflugers Arch 2006; 453:403-10. [PMID: 17001494 DOI: 10.1007/s00424-006-0149-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 08/02/2006] [Indexed: 10/24/2022]
Abstract
This review focuses on the use of imaging techniques to record electrical signaling in the fine processes of neurons such as dendrites and axons. Voltage imaging began with the use and development of externally applied voltage-sensitive dyes. With the introduction of internally applied dyes and advances in detection technology, it is now possible to record supra-threshold action potential responses, as well as sub-threshold synaptic potentials, in fine neuronal processes including dendritic spines. The development of genetically coded sensors, as well as variants of laser scanning microscopy such as second harmonic generation, offers promise for further advances in this field. Through the use and further development of these methods, optical imaging of membrane potential will continue to be a valuable tool for investigators wishing to explore the electrical events underlying single neuronal computation.
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Affiliation(s)
- Greg J Stuart
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia.
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40
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Vanzi F, Capitanio M, Sacconi L, Stringari C, Cicchi R, Canepari M, Maffei M, Piroddi N, Poggesi C, Nucciotti V, Linari M, Piazzesi G, Tesi C, Antolini R, Lombardi V, Bottinelli R, Pavone FS. New techniques in linear and non-linear laser optics in muscle research. J Muscle Res Cell Motil 2006; 27:469-79. [PMID: 16933024 DOI: 10.1007/s10974-006-9084-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Accepted: 06/26/2006] [Indexed: 11/26/2022]
Abstract
This review proposes a brief summary of two applications of lasers to muscle research. The first application (laser tweezers), is now a well-established technique in the field, adopted by several laboratories in the world and producing a constant stream of original data, fundamental for our improved understanding of muscle contraction at the level of detail that only single molecule measurements can provide. As an example of the power of this technique, here we focus on some recent results, revealing the performance of the working stroke in at least two distinct steps also in skeletal muscle myosin. A second laser-based technique described here is second-harmonic generation; the application of this technique to muscle research is very recent. We describe the main results obtained thus far in this area and the potentially remarkable impact that this technology may have in muscle research.
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Affiliation(s)
- F Vanzi
- LENS (European Laboratory for Non-linear Spectroscopy), University of Florence, Via Nello Carrara 1, 50019, Sesto Fiorentino, Firenze, Italy
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41
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Jin L, Millard AC, Wuskell JP, Dong X, Wu D, Clark HA, Loew LM. Characterization and application of a new optical probe for membrane lipid domains. Biophys J 2006; 90:2563-75. [PMID: 16415047 PMCID: PMC1403187 DOI: 10.1529/biophysj.105.072884] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this article, we characterize the fluorescence of an environmentally sensitive probe for lipid membranes, di-4-ANEPPDHQ. In large unilamellar lipid vesicles (LUVs), its emission spectrum shifts up to 30 nm to the blue with increasing cholesterol concentration. Independently, it displays a comparable blue shift in liquid-ordered relative to liquid-disordered phases. The cumulative effect is a 60-nm difference in emission spectra for cholesterol containing LUVs in the liquid-ordered state versus cholesterol-free LUVs in the liquid-disordered phase. Given these optical properties, we use di-4-ANEPPDHQ to image the phase separation in giant unilamellar vesicles with both linear and nonlinear optical microscopy. The dye shows green and red fluorescence in liquid-ordered and -disordered domains, respectively. We propose that this reflects the relative rigidity of the molecular packing around the dye molecules in the two phases. We also observe a sevenfold stronger second harmonic generation signal in the liquid-disordered domains, consistent with a higher concentration of the dye resulting from preferential partitioning into the disordered phase. The efficacy of the dye for reporting lipid domains in cell membranes is demonstrated in polarized migrating neutrophils.
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Affiliation(s)
- Lei Jin
- Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut 06030-1507, USA
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Millard AC, Jin L, Wuskell JP, Boudreau DM, Lewis A, Loew LM. Wavelength- and Time-Dependence of Potentiometric Non-linear Optical Signals from Styryl Dyes. J Membr Biol 2005; 208:103-11. [PMID: 16645740 DOI: 10.1007/s00232-005-0823-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Indexed: 11/27/2022]
Abstract
Second harmonic generation (SHG) imaging microscopy is an important emerging technique for biological research, complementing existing one- and two-photon fluorescence (2PF) methods. A non-linear phenomenon employing light from mode-locked Ti:sapphire or fiber-based lasers, SHG results in intrinsic optical sectioning without the need for a confocal aperture. Furthermore, as a second-order process SHG is confined to loci lacking a center of symmetry, a constraint that is readily satisfied by lipid membranes with only one leaflet stained by a dye. Of particular interest is "resonance-enhanced" SHG from styryl dyes in cellular membranes and the possibility that SHG is sensitive to transmembrane potential. We have previously confirmed this, using simultaneous voltage-clamping and non-linear imaging of cells to find that SHG is up to four times more sensitive to potential than fluorescence. In this work, we have extended these results in two directions. First, with a range of wavelengths available from a mode-locked Ti:sapphire laser and a fiber-based laser, we have more fully investigated SHG and 2PF voltage-sensitivity from ANEP and ASTAP chromophores, obtaining SHG sensitivity spectra that are consistent with resonance enhancements. Second, we have modified our system to coordinate the application of voltage-clamp steps with non-linear image acquisition to more precisely characterize the time dependence of SHG and 2PF voltage sensitivity, finding that, at least for some dyes, SHG responds more slowly than fluorescence to changes in transmembrane potential.
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Affiliation(s)
- A C Millard
- Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, 06030, USA
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Plotnikov SV, Millard AC, Campagnola PJ, Mohler WA. Characterization of the myosin-based source for second-harmonic generation from muscle sarcomeres. Biophys J 2005; 90:693-703. [PMID: 16258040 PMCID: PMC1367074 DOI: 10.1529/biophysj.105.071555] [Citation(s) in RCA: 325] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Several biologically important protein structures give rise to strong second-harmonic generation (SHG) in their native context. In addition to high-contrast optical sections of cells and tissues, SHG imaging can provide detailed structural information based on the physical constraints of the optical effect. In this study we characterize, by biochemical and optical analysis, the critical structures underlying SHG from the complex muscle sarcomere. SHG emission arises from domains of the sarcomere containing thick filaments, even within nascent sarcomeres of differentiating myocytes. SHG from isolated myofibrils is abolished by extraction of myosin, but is unaffected by removal or addition of actin filaments. Furthermore, the polarization dependence of sarcomeric SHG is not affected by either the proportion of myosin head domains or the orientation of myosin heads. By fitting SHG polarization anisotropy readings to theoretical response curves, we find an orientation for the elemental harmonophore that corresponds well to the pitch of the myosin rod alpha-helix along the thick filament axis. Taken together, these data indicate that myosin rod domains are the key structures giving SHG from striated muscle. This study should guide the interpretation of SHG contrast in images of cardiac and skeletal muscle tissue for a variety of biomedical applications.
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Affiliation(s)
- Sergey V Plotnikov
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3301, USA
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Dombeck DA, Sacconi L, Blanchard-Desce M, Webb WW. Optical recording of fast neuronal membrane potential transients in acute mammalian brain slices by second-harmonic generation microscopy. J Neurophysiol 2005; 94:3628-36. [PMID: 16093337 DOI: 10.1152/jn.00416.2005] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although nonlinear microscopy and fast (approximately 1 ms) membrane potential (Vm) recording have proven valuable for neuroscience applications, their potentially powerful combination has not yet been shown for studies of Vm activity deep in intact tissue. We show that laser illumination of neurons in acute rat brain slices intracellularly filled with FM4-64 dye generates an intense second-harmonic generation (SHG) signal from somatic and dendritic plasma membranes with high contrast >125 microm below the slice surface. The SHG signal provides a linear response to DeltaVm of approximately 7.5%/100 mV. By averaging repeated line scans (approximately 50), we show the ability to record action potentials (APs) optically with a signal-to-noise ratio (S/N) of approximately 7-8. We also show recording of fast Vm steps from the dendritic arbor at depths inaccessible with previous methods. The high membrane contrast and linear response of SHG to DeltaVm provides the advantage that signal changes are not degraded by background and can be directly quantified in terms of DeltaVm. Experimental comparison of SHG and two-photon fluorescence Vm recording with the best known probes for each showed that the SHG technique is superior for Vm recording in brain slice applications, with FM4-64 as the best tested SHG Vm probe.
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Affiliation(s)
- Daniel A Dombeck
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
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Abstract
Current models for cellular plasma membranes focus on spatial heterogeneity and how this heterogeneity relates to cell function. In particular, putative lipid raft membrane domains have been postulated to exist based in large part on the results that a significant fraction of the membrane is detergent insoluble and that molecules facilitating key membrane processes like signal transduction are often found in the detergent-resistant membrane fraction. Yet, the in vivo existence of lipid rafts remains extremely controversial because, despite being sought for more than a decade, evidence for their presence in intact cell membranes is inconclusive. In this review, a variety of experimental techniques that have been or might be used to look for lipid microdomains in intact cell membranes are described. Experimental results are highlighted and the strengths and limitations of different techniques for microdomain identification and characterization are assessed.
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Affiliation(s)
- B Christoffer Lagerholm
- Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
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Jin L, Millard AC, Wuskell JP, Clark HA, Loew LM. Cholesterol-enriched lipid domains can be visualized by di-4-ANEPPDHQ with linear and nonlinear optics. Biophys J 2005; 89:L04-6. [PMID: 15879475 PMCID: PMC1366585 DOI: 10.1529/biophysj.105.064816] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present a membrane-staining dye, di-4-ANEPPDHQ, which differentiates liquid-ordered phases from liquid-disordered phases coexisting in model membranes under both linear and nonlinear microscopies. The dye's fluorescence emission spectrum is blue-shifted 60 nm in liquid-ordered phases compared with liquid-disordered phases, and shows strong second harmonic generation in the liquid-disordered phase compared with the liquid-ordered phase. The ease of staining and the ability of this single dye to detect both phases, should lead to broad applications in biophysical studies of lipid domains in model membranes and cells.
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Affiliation(s)
- Lei Jin
- Department of Cell Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, Connecticut 06030-1507, USA
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Abstract
Second harmonic generation offers an important alternative and complement to fluorescence for the imaging of cellular structure and function. Staining the eggs of the sea urchin, Lytechinus pictus, with the styryl dye di-8-ANEPPS, we have observed large changes in both second harmonic generation and two-photon fluorescence after fertilization, consistent with the dynamics of exocytosis of cortical granules. With nonlinear imaging on a scanning microscope, we are able to visualize the wave of exocytosis in real time.
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Affiliation(s)
- Andrew C Millard
- Department of Cell Biology, University of Connecticut Health Center, Farmington, 06030-1507, USA
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Abstract
Nonlinear microscopy, a general term that embraces any microscopy technique based on nonlinear optics, is further establishing itself as an important tool in neurobiology. Recent advances in labels, labeling techniques, and the use of native or genetically encoded contrast agents have bolstered the capacity of nonlinear microscopes to image the structure and function of not just single cells but of entire networks of cells. Along with novel strategies to image over exceptionally long durations and with increased depth penetration in living brains, these advances are opening new opportunities in neurobiology that were previously unavailable.
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Affiliation(s)
- Jerome Mertz
- Boston University, Department of Biomedical Engineering, 44 Cummington Street, Boston, Massachusetts 02215, USA.
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Sacconi L, D'Amico M, Vanzi F, Biagiotti T, Antolini R, Olivotto M, Pavone FS. Second-harmonic generation sensitivity to transmembrane potential in normal and tumor cells. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:024014. [PMID: 15910088 DOI: 10.1117/1.1895205] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Second-harmonic generation (SHG) is emerging as a powerful tool for the optical measurement of transmembrane potential in live cells with high sensitivity and temporal resolution. Using a patch clamp, we characterize the sensitivity of the SHG signal to transmembrane potential for the RH 237 dye in various normal and tumor cell types. SHG sensitivity shows a significant dependence on the type of cell, ranging from 10 to 17% per 100 mV. Furthermore, in the samples studied, tumor cell lines display a higher sensitivity compared to normal cells. In particular, the SHG sensitivity increases in the cell line Balb/c3T3 by the transformation induced with SV40 infection of the cells. We also demonstrate that fluorescent labeling of the membrane with RH 237 at the concentration used for SHG measurements does not induce any measurable alteration in the electrophysiological properties of the cells investigated. Therefore, SHG is suitable for the investigation of outstanding questions in electrophysiology and neurobiology.
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Affiliation(s)
- L Sacconi
- University of Trento, Department of Physics, via Sommarive 14, I-38050 Povo, Trento, Italy
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