1
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Sirimatayanant S, Andruniów T. Tuning Two-Photon Absorption in Rhodopsin Chromophore via Backbone Modification: The Story Told by CC2 and TD-DFT. J Chem Theory Comput 2024. [PMID: 39269133 DOI: 10.1021/acs.jctc.4c00675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2024]
Abstract
We investigate here a systematic way to tune two-photon transition strengths (δ2PA) and two-photon absorption (2PA) cross sections (σ2PA) of the rhodopsin's chromophore 11-cis-retinal protonated Schiff base (RPSB) via the modulation of the methyl groups pattern along its polyene chain. Our team employed the resolution of identity, coupled cluster approximate second order (RI-CC2) method with Dunning's aug-cc-pVDZ basis set, to determine the structural impact on δ2PA, as well as its correlation to both transition dipole moments and permanent electric dipole moments. Seven structures were probed in vacuo, including five-double-bond-conjugated model of the native chromophore, shortened by the β-ionone ring (RPSB5), and its de/methylated analogues: 9-methyl, 13-methyl, planar and twisted models of 9,10-dimethyl and 9,10,13-trimethyl. Our results demonstrate that the magnitude of δ2PA is dictated by both the position and number of methylated groups attached to its polyene chain as well as the degree of dihedral twist that is introduced due to the de/methylation. In fact, a strong correlation between δ2PA enhancement and the presence of a C13-methyl group in the planar RPSB5 species is found. Trends in δ2PA values follow the trends observed in their corresponding changes in the permanent dipole moment upon the S0-S1 excitation nearly exactly. The assessment of four DFT functionals, i.e., M11, MN15, CAM-B3LYP, and BHandHLYP, previously found most successful in predicting 2PA properties in biological chromophores, points to a long-range-corrected hybrid meta-GGA M11 as the top-performing functional, albeit still delivering underestimated δ2PA and σ2PA values by a factor of 3.3-5.3 with respect to the CC2 results. In the case of global-hybrid meta-NGA (MN15), as well as CAM-B3LYP and BHandHLYP functionals, this factor deteriorates significantly to 6.7-20.9 and is mostly related to significantly lower quality of the ground- and excited-state dipole moments.
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Affiliation(s)
- Saruti Sirimatayanant
- Institute of Advanced Materials, Department of Chemistry, Wroclaw University of Science and Technology, Wyb. Wyspiańskiego 27, Wrocław 50-370, Poland
| | - Tadeusz Andruniów
- Institute of Advanced Materials, Department of Chemistry, Wroclaw University of Science and Technology, Wyb. Wyspiańskiego 27, Wrocław 50-370, Poland
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2
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Sims RR, Bendifallah I, Grimm C, Lafirdeen ASM, Domínguez S, Chan CY, Lu X, Forget BC, St-Pierre F, Papagiakoumou E, Emiliani V. Scanless two-photon voltage imaging. Nat Commun 2024; 15:5095. [PMID: 38876987 PMCID: PMC11178882 DOI: 10.1038/s41467-024-49192-2] [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: 12/24/2022] [Accepted: 05/28/2024] [Indexed: 06/16/2024] Open
Abstract
Two-photon voltage imaging has long been heralded as a transformative approach capable of answering many long-standing questions in modern neuroscience. However, exploiting its full potential requires the development of novel imaging approaches well suited to the photophysical properties of genetically encoded voltage indicators. We demonstrate that parallel excitation approaches developed for scanless two-photon photostimulation enable high-SNR two-photon voltage imaging. We use whole-cell patch-clamp electrophysiology to perform a thorough characterization of scanless two-photon voltage imaging using three parallel illumination approaches and lasers with different repetition rates and wavelengths. We demonstrate voltage recordings of high-frequency spike trains and sub-threshold depolarizations from neurons expressing the soma-targeted genetically encoded voltage indicator JEDI-2P-Kv. Using a low repetition-rate laser, we perform multi-cell recordings from up to fifteen targets simultaneously. We co-express JEDI-2P-Kv and the channelrhodopsin ChroME-ST and capitalize on their overlapping two-photon absorption spectra to simultaneously evoke and image action potentials using a single laser source. We also demonstrate in vivo scanless two-photon imaging of multiple cells simultaneously up to 250 µm deep in the barrel cortex of head-fixed, anaesthetised mice.
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Affiliation(s)
- Ruth R Sims
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Imane Bendifallah
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Christiane Grimm
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | | | - Soledad Domínguez
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Chung Yuen Chan
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Xiaoyu Lu
- Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX, USA
| | - Benoît C Forget
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - François St-Pierre
- Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | | | - Valentina Emiliani
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France.
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3
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Gest AMM, Lazzari-Dean JR, Ortiz G, Yaeger-Weiss SK, Boggess SC, Miller EW. A red-emitting carborhodamine for monitoring and measuring membrane potential. Proc Natl Acad Sci U S A 2024; 121:e2315264121. [PMID: 38551837 PMCID: PMC10998576 DOI: 10.1073/pnas.2315264121] [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: 10/06/2023] [Accepted: 01/25/2024] [Indexed: 04/02/2024] Open
Abstract
Biological membrane potentials, or voltages, are a central facet of cellular life. Optical methods to visualize cellular membrane voltages with fluorescent indicators are an attractive complement to traditional electrode-based approaches, since imaging methods can be high throughput, less invasive, and provide more spatial resolution than electrodes. Recently developed fluorescent indicators for voltage largely report changes in membrane voltage by monitoring voltage-dependent fluctuations in fluorescence intensity. However, it would be useful to be able to not only monitor changes but also measure values of membrane potentials. This study discloses a fluorescent indicator which can address both. We describe the synthesis of a sulfonated tetramethyl carborhodamine fluorophore. When this carborhodamine is conjugated with an electron-rich, methoxy (-OMe) containing phenylenevinylene molecular wire, the resulting molecule, CRhOMe, is a voltage-sensitive fluorophore with red/far-red fluorescence. Using CRhOMe, changes in cellular membrane potential can be read out using fluorescence intensity or lifetime. In fluorescence intensity mode, CRhOMe tracks fast-spiking neuronal action potentials (APs) with greater signal-to-noise than state-of-the-art BeRST 1 (another voltage-sensitive fluorophore). CRhOMe can also measure values of membrane potential. The fluorescence lifetime of CRhOMe follows a single exponential decay, substantially improving the quantification of membrane potential values using fluorescence lifetime imaging microscopy (FLIM). The combination of red-shifted excitation and emission, mono-exponential decay, and high voltage sensitivity enable fast FLIM recording of APs in cardiomyocytes. The ability to both monitor and measure membrane potentials with red light using CRhOMe makes it an important approach for studying biological voltages.
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Affiliation(s)
| | | | - Gloria Ortiz
- Department of Chemistry, University of California, Berkeley, CA 94720
| | | | - Steven C Boggess
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Evan W Miller
- Department of Chemistry, University of California, Berkeley, CA 94720
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720
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4
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Turnbull JL, Miller EW. An open and shut case? Chemistry to control xanthene dyes. TRENDS IN CHEMISTRY 2024; 6:164-172. [PMID: 39036609 PMCID: PMC11257214 DOI: 10.1016/j.trechm.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
Fluorescent dyes are an indispensable part of the scientific enterprise. Xanthene-based fluorophores, like fluorescein and rhodamine, have been in continual use across numerous fields since their invention in the late 19th century. Modern methods to synthesize and expand the scope of xanthene dye chemistry have enabled new colors, enhanced stability, and improved brightness. Modifications to the 3-position of xanthene dyes have been, until recently, less well-explored. Here, we discuss how small changes to the identity of the substituent at the 3-position of fluoresceins and rhodamines can profoundly alter the properties of xanthene dyes, with the potential to unlock new applications at the interface of chemistry and biology.
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Affiliation(s)
- Joshua L. Turnbull
- Department of Chemistry, University of California, Berkeley, CA 94720, United States of America
| | - Evan W. Miller
- Department of Chemistry, University of California, Berkeley, CA 94720, United States of America
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, United States of America
- Helen Wills Neuroscience Institute University of California, Berkeley, CA 94720, United States of America
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5
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Lam CK, Fung LY, Wang Y. Orientation and Membrane Partition Free Energy of PeT-Based Voltage-Sensitive Dyes from Molecular Simulations. J Phys Chem B 2024; 128:2734-2744. [PMID: 38459942 PMCID: PMC10961725 DOI: 10.1021/acs.jpcb.3c08090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/19/2024] [Accepted: 02/20/2024] [Indexed: 03/11/2024]
Abstract
Voltage measurement via small-molecule fluorescent indicators is a valuable approach in deciphering complex dynamics in electrically excitable cells. However, our understanding of various physicochemical properties governing the performance of fluorescent voltage sensors based on the photoinduced electron transfer (PeT) mechanism remains incomplete. Here, through extensive molecular dynamics and free energy calculations, we systematically examine the orientation and membrane partition of three PeT-based voltage-sensing VoltageFluor (VF) dyes in different lipid environment. We show that the symmetry of the molecular scaffold and the net charge of the hydrophilic headgroup of a given VF dye dominate its orientation and membrane partition, respectively. Our work provides a mechanistic understanding of the physical properties contributing to the voltage sensitivity, signal-to-noise ratio, as well as membrane distribution of VF dyes and sheds light onto rational design principles of PeT-based fluorescent probes in general.
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Affiliation(s)
- Chun Kei Lam
- Department of Physics, The
Chinese University
of Hong Kong, Shatin, Hong Kong SAR, China
| | - Lap Yan Fung
- Department of Physics, The
Chinese University
of Hong Kong, Shatin, Hong Kong SAR, China
| | - Yi Wang
- Department of Physics, The
Chinese University
of Hong Kong, Shatin, Hong Kong SAR, China
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6
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Turnbull JL, Golden RP, Benlian BR, Henn KM, Lipman SM, Miller EW. Mild and scalable synthesis of phosphonorhodamines. Chem Sci 2023; 14:11365-11373. [PMID: 37886078 PMCID: PMC10599461 DOI: 10.1039/d3sc02590j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 08/28/2023] [Indexed: 10/28/2023] Open
Abstract
Since their discovery in 1887, rhodamines have become indispensable fluorophores for biological imaging. Recent studies have extensively explored heteroatom substitution at the 10' position and a variety of substitution patterns on the 3',6' nitrogens. Although 3-carboxy- and 3-sulfono-rhodamines were first reported in the 19th century, the 3-phosphono analogues have never been reported. Here, we report a mild, scalable synthetic route to 3-phosphonorhodamines. We explore the substrate scope and investigate mechanistic details of an exogenous acid-free condensation. Tetramethyl-3-phosphonorhodamine (phosTMR) derivatives can be accessed on the 1.5 mmol scale in up to 98% yield (2 steps). phosTMR shows a 12- to 500-fold increase in water solubility relative to 3-carboxy and 3-sulfonorhodamine derivatives and has excellent chemical stability. Additionally, phosphonates allow for chemical derivatization; esterification of phosTMR facilitates intracellular delivery with localization profiles that differ from 3-carboxyrhodamines. The free phosphonate can be incorporated into a molecular wire scaffold to create a phosphonated rhodamine voltage reporter, phosphonoRhoVR. PhosRhoVR 1 can be synthesized in just 6 steps, with an overall yield of 37% to provide >400 mg of material, compared to a 6-step, ∼2% yield for the previously reported RhoVR 1. PhosRhoVR 1 possesses excellent voltage sensitivity (37% ΔF/F) and a 2-fold increase in cellular brightness compared to RhoVR 1.
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Affiliation(s)
- Joshua L Turnbull
- Department of Chemistry, University of California Berkeley CA 94720-1460 USA
| | - Ryan P Golden
- Department of Chemistry, University of California Berkeley CA 94720-1460 USA
| | - Brittany R Benlian
- Department of Molecular & Cell Biology, University of California Berkeley CA 94720-1460 USA
| | - Katharine M Henn
- Helen Wills Neuroscience Institute, University of California Berkeley CA 94720-1460 USA
| | - Soren M Lipman
- Department of Chemistry, University of California Berkeley CA 94720-1460 USA
| | - Evan W Miller
- Department of Chemistry, University of California Berkeley CA 94720-1460 USA
- Department of Molecular & Cell Biology, University of California Berkeley CA 94720-1460 USA
- Helen Wills Neuroscience Institute, University of California Berkeley CA 94720-1460 USA
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7
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Bounds HA, Sadahiro M, Hendricks WD, Gajowa M, Gopakumar K, Quintana D, Tasic B, Daigle TL, Zeng H, Oldenburg IA, Adesnik H. All-optical recreation of naturalistic neural activity with a multifunctional transgenic reporter mouse. Cell Rep 2023; 42:112909. [PMID: 37542722 PMCID: PMC10755854 DOI: 10.1016/j.celrep.2023.112909] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/23/2023] [Accepted: 07/14/2023] [Indexed: 08/07/2023] Open
Abstract
Determining which features of the neural code drive behavior requires the ability to simultaneously read out and write in neural activity patterns with high precision across many neurons. All-optical systems that combine two-photon calcium imaging and targeted photostimulation enable the activation of specific, functionally defined groups of neurons. However, these techniques are unable to test how patterns of activity across a population contribute to computation because of an inability to both read and write cell-specific firing rates. To overcome this challenge, we make two advances: first, we introduce a genetic line of mice for Cre-dependent co-expression of a calcium indicator and a potent soma-targeted microbial opsin. Second, using this line, we develop a method for read-out and write-in of precise population vectors of neural activity by calibrating the photostimulation to each cell. These advances offer a powerful and convenient platform for investigating the neural codes of computation and behavior.
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Affiliation(s)
- Hayley A Bounds
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA; The Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Masato Sadahiro
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - William D Hendricks
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Marta Gajowa
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Karthika Gopakumar
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Daniel Quintana
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | | | | | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Ian Antón Oldenburg
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
| | - Hillel Adesnik
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA; The Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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8
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Sirimatayanant S, Andruniów T. Benchmarking two-photon absorption strengths of rhodopsin chromophore models with CC3 and CCSD methodologies: An assessment of popular density functional approximations. J Chem Phys 2023; 158:094106. [PMID: 36889953 DOI: 10.1063/5.0135594] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
This work presents the investigations of the impact of an increasing electron correlation in the hierarchy of coupled-cluster methods, i.e., CC2, CCSD, and CC3, on two-photon absorption (2PA) strengths for the lowest excited state of the minimal rhodopsin's chromophore model-cis-penta-2,4-dieniminium cation (PSB3). For a larger chromophore's model [4-cis-hepta-2,4,6-trieniminium cation (PSB4)], CC2 and CCSD calculations of 2PA strengths were performed. Additionally, 2PA strengths predicted by some popular density functional theory (DFT) functionals differing in HF exchange contribution were assessed against the reference CC3/CCSD data. For PSB3, the accuracy of 2PA strengths increases in the following order: CC2 < CCSD < CC3, with the CC2 deviation from both higher-level methods exceeding 10% at 6-31+G* basis sets and 2% at aug-cc-pVDZ basis set. However, for PSB4, this trend is reversed and CC2-based 2PA strength is larger than the corresponding CCSD value. Among the DFT functionals investigated, CAM-B3LYP and BHandHLYP provide 2PA strengths in best compliance with reference data, however, with the error approaching an order of magnitude.
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Affiliation(s)
- Saruti Sirimatayanant
- Institute of Advanced Materials, Department of Chemistry, Wroclaw University of Science and Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Tadeusz Andruniów
- Institute of Advanced Materials, Department of Chemistry, Wroclaw University of Science and Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw, Poland
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9
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Sims RR, Bendifallah I, Grimm C, Mohamed-Lafirdeen A, Lu X, St-Pierre F, Papagiakoumou E, Emiliani V. Scanless two-photon voltage imaging. RESEARCH SQUARE 2023:rs.3.rs-2412371. [PMID: 36747617 PMCID: PMC9900978 DOI: 10.21203/rs.3.rs-2412371/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Parallel light-sculpting methods have been used to perform scanless two-photon photostimulation of multiple neurons simultaneously during all-optical neurophysiology experiments. We demonstrate that scanless two-photon excitation also enables high-resolution, high-contrast, voltage imaging by efficiently exciting fluorescence in a large fraction of the cellular soma. We present a thorough characterisation of scanless two-photon voltage imaging using existing parallel approaches and lasers with different repetition rates. We demonstrate voltage recordings of high frequency spike trains and sub-threshold depolarizations in intact brain tissue from neurons expressing the soma-targeted genetically encoded voltage indicator JEDI-2P-kv. Using a low repetition-rate laser, we perform recordings from up to ten neurons simultaneously. Finally, by co-expressing JEDI-2P-kv and the channelrhodopsin ChroME-ST in neurons of hippocampal organotypic slices, we perform single-beam, simultaneous, two-photon voltage imaging and photostimulation. This enables in-situ validation of the precise number and timing of light evoked action potentials and will pave the way for rapid and scalable identification of functional brain connections in intact neural circuits.
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Affiliation(s)
- Ruth R. Sims
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, F-75012 Paris, France
| | - Imane Bendifallah
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, F-75012 Paris, France
| | - Christiane Grimm
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, F-75012 Paris, France
| | | | - Xiaoyu Lu
- Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX, USA
| | - François St-Pierre
- Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX, USA
- Department of Neuroscience and Department of Biochemistry and Molecular Biology, Houston, TX, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | | | - Valentina Emiliani
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, F-75012 Paris, France
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10
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Raliski BK, Mun DM, Miller EW. Sulfone Rhodamines for Voltage Imaging. Chem Asian J 2022; 17:e202200906. [PMID: 36356288 PMCID: PMC9772261 DOI: 10.1002/asia.202200906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/11/2022] [Indexed: 11/12/2022]
Abstract
Fluorescent indicators that respond to changes in biological membrane potentials provide a powerful complement to existing methods for monitoring neuronal activity. Indicators that absorb and emit in the near infrared window are especially attractive, since lower energy wavelengths excite fewer biological molecules and can penetrate more deeply into biological tissues. In this work, we incorporate sulfone rhodamine chromophores into a voltage-sensitive scaffold in order to generate voltage sensitive fluorophores which absorb and emit above 700 nm. These Sulfone Rhodamine Voltage Reporters (SuRhoVRs) partition into cell membranes and display good sensitivity to membrane potential changes. The most sensitive SuRhoVR derivative also displays excellent photostability and can track membrane potential changes in dissociated rat hippocampal neurons.
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Affiliation(s)
- Benjamin K. Raliski
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720-1460, USA
| | - Dong Min Mun
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720-1460, USA
| | - Evan W. Miller
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720-1460, USA,Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720-1460, USA,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720-1460, USA
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11
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Guilbert J, Légaré A, De Koninck P, Desrosiers P, Desjardins M. Toward an integrative neurovascular framework for studying brain networks. NEUROPHOTONICS 2022; 9:032211. [PMID: 35434179 PMCID: PMC8989057 DOI: 10.1117/1.nph.9.3.032211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/11/2022] [Indexed: 05/28/2023]
Abstract
Brain functional connectivity based on the measure of blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signals has become one of the most widely used measurements in human neuroimaging. However, the nature of the functional networks revealed by BOLD fMRI can be ambiguous, as highlighted by a recent series of experiments that have suggested that typical resting-state networks can be replicated from purely vascular or physiologically driven BOLD signals. After going through a brief review of the key concepts of brain network analysis, we explore how the vascular and neuronal systems interact to give rise to the brain functional networks measured with BOLD fMRI. This leads us to emphasize a view of the vascular network not only as a confounding element in fMRI but also as a functionally relevant system that is entangled with the neuronal network. To study the vascular and neuronal underpinnings of BOLD functional connectivity, we consider a combination of methodological avenues based on multiscale and multimodal optical imaging in mice, used in combination with computational models that allow the integration of vascular information to explain functional connectivity.
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Affiliation(s)
- Jérémie Guilbert
- Université Laval, Department of Physics, Physical Engineering, and Optics, Québec, Canada
- Université Laval, Centre de recherche du CHU de Québec, Québec, Canada
| | - Antoine Légaré
- Université Laval, Department of Physics, Physical Engineering, and Optics, Québec, Canada
- Centre de recherche CERVO, Québec, Canada
- Université Laval, Department of Biochemistry, Microbiology, and Bioinformatics, Québec, Canada
| | - Paul De Koninck
- Centre de recherche CERVO, Québec, Canada
- Université Laval, Department of Biochemistry, Microbiology, and Bioinformatics, Québec, Canada
| | - Patrick Desrosiers
- Université Laval, Department of Physics, Physical Engineering, and Optics, Québec, Canada
- Centre de recherche CERVO, Québec, Canada
| | - Michèle Desjardins
- Université Laval, Department of Physics, Physical Engineering, and Optics, Québec, Canada
- Université Laval, Centre de recherche du CHU de Québec, Québec, Canada
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12
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Fiala T, Mosharov EV, Wang J, Mendieta AM, Choi SJ, Fialova E, Hwu C, Sulzer D, Sames D. Chemical Targeting of Rhodol Voltage-Sensitive Dyes to Dopaminergic Neurons. ACS Chem Neurosci 2022; 13:1251-1262. [PMID: 35400149 DOI: 10.1021/acschemneuro.1c00862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Optical imaging of changes in the membrane potential of living cells can be achieved by means of fluorescent voltage-sensitive dyes (VSDs). A particularly challenging task is to efficiently deliver these highly lipophilic probes to specific neuronal subpopulations in brain tissue. We have tackled this task by designing a solubilizing, hydrophilic polymer platform that carries a high-affinity ligand for a membrane protein marker of interest and a fluorescent VSD. Here, we disclose an improved design of polymer-supported probes for chemical, nongenetic targeting of voltage sensors to axons natively expressing the dopamine transporter in ex vivo mouse brain tissue. We first show that for negatively charged rhodol VSDs functioning on the photoinduced electron transfer principle, poly(ethylene glycol) as a carrier enables targeting with higher selectivity than the polysaccharide dextran in HEK cell culture. In the same experimental setting, we also demonstrate that incorporation of an azetidine ring into the rhodol chromophore substantially increases the brightness and voltage sensitivity of the respective VSD. We show that the superior properties of the optimized sensor are transferable to recording of electrically evoked activity from dopaminergic axons in mouse striatal slices after averaging of multiple trials. Finally, we suggest the next milestones for the field to achieve single-scan recordings with nongenetically targeted VSDs in native brain tissue.
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Affiliation(s)
- Tomas Fiala
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Eugene V. Mosharov
- Department of Neurology, Columbia University Irving Medical Center, New York, New York 10032, United States
| | - Jihang Wang
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Adriana M. Mendieta
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Se Joon Choi
- Department of Psychiatry, Columbia University Irving Medical Center, New York, New York 10032, United States
| | - Eva Fialova
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Christopher Hwu
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - David Sulzer
- Department of Neurology, Columbia University Irving Medical Center, New York, New York 10032, United States
- Department of Psychiatry, Columbia University Irving Medical Center, New York, New York 10032, United States
- Department of Pharmacology, Columbia University Irving Medical Center, New York, New York 10032, United States
- Department of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, United States
| | - Dalibor Sames
- Department of Chemistry, Columbia University, New York, New York 10027, United States
- NeuroTechnology Center at Columbia University, New York, New York 10027, United States
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13
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Abdelfattah AS, Ahuja S, Akkin T, Allu SR, Brake J, Boas DA, Buckley EM, Campbell RE, Chen AI, Cheng X, Čižmár T, Costantini I, De Vittorio M, Devor A, Doran PR, El Khatib M, Emiliani V, Fomin-Thunemann N, Fainman Y, Fernandez-Alfonso T, Ferri CGL, Gilad A, Han X, Harris A, Hillman EMC, Hochgeschwender U, Holt MG, Ji N, Kılıç K, Lake EMR, Li L, Li T, Mächler P, Miller EW, Mesquita RC, Nadella KMNS, Nägerl UV, Nasu Y, Nimmerjahn A, Ondráčková P, Pavone FS, Perez Campos C, Peterka DS, Pisano F, Pisanello F, Puppo F, Sabatini BL, Sadegh S, Sakadzic S, Shoham S, Shroff SN, Silver RA, Sims RR, Smith SL, Srinivasan VJ, Thunemann M, Tian L, Tian L, Troxler T, Valera A, Vaziri A, Vinogradov SA, Vitale F, Wang LV, Uhlířová H, Xu C, Yang C, Yang MH, Yellen G, Yizhar O, Zhao Y. Neurophotonic tools for microscopic measurements and manipulation: status report. NEUROPHOTONICS 2022; 9:013001. [PMID: 35493335 PMCID: PMC9047450 DOI: 10.1117/1.nph.9.s1.013001] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Neurophotonics was launched in 2014 coinciding with the launch of the BRAIN Initiative focused on development of technologies for advancement of neuroscience. For the last seven years, Neurophotonics' agenda has been well aligned with this focus on neurotechnologies featuring new optical methods and tools applicable to brain studies. While the BRAIN Initiative 2.0 is pivoting towards applications of these novel tools in the quest to understand the brain, this status report reviews an extensive and diverse toolkit of novel methods to explore brain function that have emerged from the BRAIN Initiative and related large-scale efforts for measurement and manipulation of brain structure and function. Here, we focus on neurophotonic tools mostly applicable to animal studies. A companion report, scheduled to appear later this year, will cover diffuse optical imaging methods applicable to noninvasive human studies. For each domain, we outline the current state-of-the-art of the respective technologies, identify the areas where innovation is needed, and provide an outlook for the future directions.
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Affiliation(s)
- Ahmed S. Abdelfattah
- Brown University, Department of Neuroscience, Providence, Rhode Island, United States
| | - Sapna Ahuja
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Taner Akkin
- University of Minnesota, Department of Biomedical Engineering, Minneapolis, Minnesota, United States
| | - Srinivasa Rao Allu
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Joshua Brake
- Harvey Mudd College, Department of Engineering, Claremont, California, United States
| | - David A. Boas
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Erin M. Buckley
- Georgia Institute of Technology and Emory University, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
- Emory University, Department of Pediatrics, Atlanta, Georgia, United States
| | - Robert E. Campbell
- University of Tokyo, Department of Chemistry, Tokyo, Japan
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Anderson I. Chen
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Xiaojun Cheng
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Tomáš Čižmár
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Irene Costantini
- University of Florence, European Laboratory for Non-Linear Spectroscopy, Department of Biology, Florence, Italy
- National Institute of Optics, National Research Council, Rome, Italy
| | - Massimo De Vittorio
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Anna Devor
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Patrick R. Doran
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Mirna El Khatib
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | | | - Natalie Fomin-Thunemann
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Yeshaiahu Fainman
- University of California San Diego, Department of Electrical and Computer Engineering, La Jolla, California, United States
| | - Tomas Fernandez-Alfonso
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Christopher G. L. Ferri
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Ariel Gilad
- The Hebrew University of Jerusalem, Institute for Medical Research Israel–Canada, Department of Medical Neurobiology, Faculty of Medicine, Jerusalem, Israel
| | - Xue Han
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Andrew Harris
- Weizmann Institute of Science, Department of Brain Sciences, Rehovot, Israel
| | | | - Ute Hochgeschwender
- Central Michigan University, Department of Neuroscience, Mount Pleasant, Michigan, United States
| | - Matthew G. Holt
- University of Porto, Instituto de Investigação e Inovação em Saúde (i3S), Porto, Portugal
| | - Na Ji
- University of California Berkeley, Department of Physics, Berkeley, California, United States
| | - Kıvılcım Kılıç
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Evelyn M. R. Lake
- Yale School of Medicine, Department of Radiology and Biomedical Imaging, New Haven, Connecticut, United States
| | - Lei Li
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Tianqi Li
- University of Minnesota, Department of Biomedical Engineering, Minneapolis, Minnesota, United States
| | - Philipp Mächler
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Evan W. Miller
- University of California Berkeley, Departments of Chemistry and Molecular & Cell Biology and Helen Wills Neuroscience Institute, Berkeley, California, United States
| | | | | | - U. Valentin Nägerl
- Interdisciplinary Institute for Neuroscience University of Bordeaux & CNRS, Bordeaux, France
| | - Yusuke Nasu
- University of Tokyo, Department of Chemistry, Tokyo, Japan
| | - Axel Nimmerjahn
- Salk Institute for Biological Studies, Waitt Advanced Biophotonics Center, La Jolla, California, United States
| | - Petra Ondráčková
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Francesco S. Pavone
- National Institute of Optics, National Research Council, Rome, Italy
- University of Florence, European Laboratory for Non-Linear Spectroscopy, Department of Physics, Florence, Italy
| | - Citlali Perez Campos
- Columbia University, Zuckerman Mind Brain Behavior Institute, New York, United States
| | - Darcy S. Peterka
- Columbia University, Zuckerman Mind Brain Behavior Institute, New York, United States
| | - Filippo Pisano
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Ferruccio Pisanello
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Francesca Puppo
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Bernardo L. Sabatini
- Harvard Medical School, Howard Hughes Medical Institute, Department of Neurobiology, Boston, Massachusetts, United States
| | - Sanaz Sadegh
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Sava Sakadzic
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Shy Shoham
- New York University Grossman School of Medicine, Tech4Health and Neuroscience Institutes, New York, New York, United States
| | - Sanaya N. Shroff
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - R. Angus Silver
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Ruth R. Sims
- Sorbonne University, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Spencer L. Smith
- University of California Santa Barbara, Department of Electrical and Computer Engineering, Santa Barbara, California, United States
| | - Vivek J. Srinivasan
- New York University Langone Health, Departments of Ophthalmology and Radiology, New York, New York, United States
| | - Martin Thunemann
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Lei Tian
- Boston University, Departments of Electrical Engineering and Biomedical Engineering, Boston, Massachusetts, United States
| | - Lin Tian
- University of California Davis, Department of Biochemistry and Molecular Medicine, Davis, California, United States
| | - Thomas Troxler
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Antoine Valera
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Alipasha Vaziri
- Rockefeller University, Laboratory of Neurotechnology and Biophysics, New York, New York, United States
- The Rockefeller University, The Kavli Neural Systems Institute, New York, New York, United States
| | - Sergei A. Vinogradov
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Flavia Vitale
- Center for Neuroengineering and Therapeutics, Departments of Neurology, Bioengineering, Physical Medicine and Rehabilitation, Philadelphia, Pennsylvania, United States
| | - Lihong V. Wang
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Hana Uhlířová
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Chris Xu
- Cornell University, School of Applied and Engineering Physics, Ithaca, New York, United States
| | - Changhuei Yang
- California Institute of Technology, Departments of Electrical Engineering, Bioengineering and Medical Engineering, Pasadena, California, United States
| | - Mu-Han Yang
- University of California San Diego, Department of Electrical and Computer Engineering, La Jolla, California, United States
| | - Gary Yellen
- Harvard Medical School, Department of Neurobiology, Boston, Massachusetts, United States
| | - Ofer Yizhar
- Weizmann Institute of Science, Department of Brain Sciences, Rehovot, Israel
| | - Yongxin Zhao
- Carnegie Mellon University, Department of Biological Sciences, Pittsburgh, Pennsylvania, United States
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14
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Kirk MJ, Benlian BR, Han Y, Gold A, Ravi A, Deal PE, Molina RS, Drobizhev M, Dickman D, Scott K, Miller EW. Voltage Imaging in Drosophila Using a Hybrid Chemical-Genetic Rhodamine Voltage Reporter. Front Neurosci 2021; 15:754027. [PMID: 34867164 PMCID: PMC8637050 DOI: 10.3389/fnins.2021.754027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/15/2021] [Indexed: 12/03/2022] Open
Abstract
We combine a chemically-synthesized, voltage-sensitive fluorophore with a genetically encoded, self-labeling enzyme to enable voltage imaging in Drosophila melanogaster. Previously, we showed that a rhodamine voltage reporter (RhoVR) combined with the HaloTag self-labeling enzyme could be used to monitor membrane potential changes from mammalian neurons in culture and brain slice. Here, we apply this hybrid RhoVR-Halo approach in vivo to achieve selective neuron labeling in intact fly brains. We generate a Drosophila UAS-HaloTag reporter line in which the HaloTag enzyme is expressed on the surface of cells. We validate the voltage sensitivity of this new construct in cell culture before driving expression of HaloTag in specific brain neurons in flies. We show that selective labeling of synapses, cells, and brain regions can be achieved with RhoVR-Halo in either larval neuromuscular junction (NMJ) or in whole adult brains. Finally, we validate the voltage sensitivity of RhoVR-Halo in fly tissue via dual-electrode/imaging at the NMJ, show the efficacy of this approach for measuring synaptic excitatory post-synaptic potentials (EPSPs) in muscle cells, and perform voltage imaging of carbachol-evoked depolarization and osmolarity-evoked hyperpolarization in projection neurons and in interoceptive subesophageal zone neurons in fly brain explants following in vivo labeling. We envision the turn-on response to depolarizations, fast response kinetics, and two-photon compatibility of chemical indicators, coupled with the cellular and synaptic specificity of genetically-encoded enzymes, will make RhoVR-Halo a powerful complement to neurobiological imaging in Drosophila.
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Affiliation(s)
- Molly J. Kirk
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Brittany R. Benlian
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Yifu Han
- Department of Neurobiology, University of Southern California, Los Angeles, CA, United States
| | - Arya Gold
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, United States
| | - Ashvin Ravi
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, United States
| | - Parker E. Deal
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, United States
| | - Rosana S. Molina
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Mikhail Drobizhev
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA, United States
| | - Kristin Scott
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
| | - Evan W. Miller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, United States
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
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15
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Talone B, Pozzi P, Cavagnini M, Polli D, Pozzi G, Mapelli J. Experimental determination of shift-less aberration bases for sensorless adaptive optics in nonlinear microscopy. OPTICS EXPRESS 2021; 29:37617-37627. [PMID: 34808830 DOI: 10.1364/oe.435262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
Adaptive optics can improve the performance of optical systems and devices by correcting phase aberrations. While in most applications wavefront sensing is employed to drive the adaptive optics correction, some microscopy methods may require sensorless optimization of the wavefront. In these cases, the correction is performed by describing the aberration as a linear combination of a base of influence functions, optimizing an image quality metric as a function of the coefficients. The influence functions base is generally chosen to either efficiently represent the adaptive device used or to describe generic wavefronts in an orthogonal fashion. A rarely discussed problem is that most correction bases have elements which introduce, together with a correction of the aberration, a shift of the imaging field of view in three dimensions. While simple methods to solve the problem are available for linear microscopy methods, nonlinear microscopy techniques such as multiphoton or second harmonic generation microscopy require non-trivial base determination. In this paper, we discuss the problem, and we present a method for calibrating a shift-less base on a spatial light modulator for two-photon microscopy.
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16
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Adesnik H, Abdeladim L. Probing neural codes with two-photon holographic optogenetics. Nat Neurosci 2021; 24:1356-1366. [PMID: 34400843 PMCID: PMC9793863 DOI: 10.1038/s41593-021-00902-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/30/2021] [Indexed: 02/07/2023]
Abstract
Optogenetics ushered in a revolution in how neuroscientists interrogate brain function. Because of technical limitations, the majority of optogenetic studies have used low spatial resolution activation schemes that limit the types of perturbations that can be made. However, neural activity manipulations at finer spatial scales are likely to be important to more fully understand neural computation. Spatially precise multiphoton holographic optogenetics promises to address this challenge and opens up many new classes of experiments that were not previously possible. More specifically, by offering the ability to recreate extremely specific neural activity patterns in both space and time in functionally defined ensembles of neurons, multiphoton holographic optogenetics could allow neuroscientists to reveal fundamental aspects of the neural codes for sensation, cognition and behavior that have been beyond reach. This Review summarizes recent advances in multiphoton holographic optogenetics that substantially expand its capabilities, highlights outstanding technical challenges and provides an overview of the classes of experiments it can execute to test and validate key theoretical models of brain function. Multiphoton holographic optogenetics could substantially accelerate the pace of neuroscience discovery by helping to close the loop between experimental and theoretical neuroscience, leading to fundamental new insights into nervous system function and disorder.
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Affiliation(s)
- Hillel Adesnik
- Department of Molecular and Cell Biology and the Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA.
| | - Lamiae Abdeladim
- Department of Molecular and Cell Biology and the Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA
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17
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Grupi A, Shapira Z, Yudovich S, Degani-Katzav N, Weiss S. Point-localized, site-specific membrane potential optical recording by single fluorescent nanodiscs. ACTA ACUST UNITED AC 2021; 1:None. [PMID: 34568861 PMCID: PMC8448295 DOI: 10.1016/j.bpr.2021.100007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/20/2021] [Indexed: 01/02/2023]
Abstract
Nanodisc technology was implemented as a platform for voltage nanosensors. A fluorescence (Förster) resonance energy transfer (FRET)- based voltage-sensing scheme employing fluorescent nanodiscs and the hydrophobic ion dipicrylamine was developed and utilized to optically record membrane potentials on the single-nanodisc level. Ensemble and single-nanosensor recordings were demonstrated for HEK293 cells and primary cortical neuron cells. Conjugation of nanodiscs to anti-GABAA antibodies allowed for site-specific membrane potential measurements from postsynaptic sites.
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Affiliation(s)
- Asaf Grupi
- Department of Physics, Institute for Nanotechnology and Advanced Materials.,Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Zehavit Shapira
- Department of Physics, Institute for Nanotechnology and Advanced Materials.,Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Shimon Yudovich
- Department of Physics, Institute for Nanotechnology and Advanced Materials.,Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Nurit Degani-Katzav
- Department of Physics, Institute for Nanotechnology and Advanced Materials.,Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Shimon Weiss
- Department of Physics, Institute for Nanotechnology and Advanced Materials.,Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel.,Department of Chemistry and Biochemistry.,California NanoSystems Institute, University of California Los Angeles, Los Angeles, California
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18
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Lazzari-Dean JR, Miller EW. Optical Estimation of Absolute Membrane Potential Using One- and Two-Photon Fluorescence Lifetime Imaging Microscopy. Bioelectricity 2021; 3:197-203. [PMID: 34734167 DOI: 10.1089/bioe.2021.0007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Background: Membrane potential (V mem) exerts physiological influence across a wide range of time and space scales. To study V mem in these diverse contexts, it is essential to accurately record absolute values of V mem, rather than solely relative measurements. Materials and Methods: We use fluorescence lifetime imaging of a small molecule voltage sensitive dye (VF2.1.Cl) to estimate mV values of absolute membrane potential. Results: We test the consistency of VF2.1.Cl lifetime measurements performed on different single-photon counting instruments and find that they are in striking agreement (differences of <0.5 ps/mV in the slope and <50 ps in the y-intercept). We also demonstrate that VF2.1.Cl lifetime reports absolute V mem under two-photon (2P) illumination with better than 20 mV of V mem resolution, a nearly 10-fold improvement over other lifetime-based methods. Conclusions: We demonstrate that VF-FLIM is a robust and portable metric for V mem across imaging platforms and under both one-photon and 2P illumination. This work is a critical foundation for application of VF-FLIM to record absolute membrane potential signals in thick tissue.
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Affiliation(s)
- Julia R Lazzari-Dean
- Department of Chemistry, University of California, Berkeley, Berkeley, California, USA
| | - Evan W Miller
- Department of Chemistry, University of California, Berkeley, Berkeley, California, USA.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California, USA
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19
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Vygranenko KV, Poronik YM, Wrzosek A, Szewczyk A, Gryko DT. Red emissive sulfone-rhodols as mitochondrial imaging agents. Chem Commun (Camb) 2021; 57:7782-7785. [PMID: 34263888 DOI: 10.1039/d1cc02687a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The controlled hydrolysis of sulfone-rhodamines affords a series of core-modified red-emitting rhodols, the fluorescence of which is sensitive to solvent polarity with pronounced bathochromic shifts recorded in both DMSO and CH3CN combined with an up to 8-fold increase in the fluorescence quantum yield.
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Affiliation(s)
- Kateryna V Vygranenko
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Yevgen M Poronik
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Antoni Wrzosek
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland.
| | - Adam Szewczyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland.
| | - Daniel T Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
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20
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Post MR, Sulzer D. The chemical tools for imaging dopamine release. Cell Chem Biol 2021; 28:748-764. [PMID: 33894160 PMCID: PMC8532025 DOI: 10.1016/j.chembiol.2021.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/23/2021] [Accepted: 04/06/2021] [Indexed: 02/07/2023]
Abstract
Dopamine is a modulatory neurotransmitter involved in learning, motor functions, and reward. Many neuropsychiatric disorders, including Parkinson's disease, autism, and schizophrenia, are associated with imbalances or dysfunction in the dopaminergic system. Yet, our understanding of these pervasive public health issues is limited by our ability to effectively image dopamine in humans, which has long been a goal for chemists and neuroscientists. The last two decades have witnessed the development of many molecules used to trace dopamine. We review the small molecules, nanoparticles, and protein sensors used with fluorescent microscopy/photometry, MRI, and PET that shape dopamine research today. None of these tools observe dopamine itself, but instead harness the biology of the dopamine system-its synthetic and metabolic pathways, synaptic vesicle cycle, and receptors-in elegant ways. Their advantages and weaknesses are covered here, along with recent examples and the chemistry and biology that allow them to function.
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Affiliation(s)
- Michael R Post
- Department of Psychiatry, Columbia University Medical Center, New York, NY, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA.
| | - David Sulzer
- Departments of Psychiatry, Neurology, and Pharmacology, Columbia University Medical Center, New York, NY, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA.
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21
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Chien MP, Brinks D, Testa-Silva G, Tian H, Phil Brooks F, Adam Y, Bloxham B, Gmeiner B, Kheifets S, Cohen AE. Photoactivated voltage imaging in tissue with an archaerhodopsin-derived reporter. SCIENCE ADVANCES 2021; 7:7/19/eabe3216. [PMID: 33952514 PMCID: PMC8099184 DOI: 10.1126/sciadv.abe3216] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 03/15/2021] [Indexed: 05/19/2023]
Abstract
Photoactivated genetically encoded voltage indicators (GEVIs) have the potential to enable optically sectioned voltage imaging at the intersection of a photoactivation beam and an imaging beam. We developed a pooled high-throughput screen to identify archaerhodopsin mutants with enhanced photoactivation. After screening ~105 cells, we identified a novel GEVI, NovArch, whose one-photon near-infrared fluorescence is reversibly enhanced by weak one-photon blue or two-photon near-infrared excitation. Because the photoactivation leads to fluorescent signals catalytically rather than stoichiometrically, high fluorescence signals, optical sectioning, and high time resolution are achieved simultaneously at modest blue or two-photon laser power. We demonstrate applications of the combined molecular and optical tools to optical mapping of membrane voltage in distal dendrites in acute mouse brain slices and in spontaneously active neurons in vivo.
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Affiliation(s)
- Miao-Ping Chien
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, Netherlands
- Oncode Institute, Utrecht, Netherlands
| | - Daan Brinks
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, Netherlands
- Department of Imaging Physics, Delft University of Technology, Delft, Netherlands
| | - Guilherme Testa-Silva
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Howard Hughes Medical Institute, Cambridge, MA 02138, USA
| | - He Tian
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - F Phil Brooks
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Yoav Adam
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Blox Bloxham
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Benjamin Gmeiner
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Simon Kheifets
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Adam E Cohen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
- Howard Hughes Medical Institute, Cambridge, MA 02138, USA
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22
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Gonzalez MA, Walker AS, Cao KJ, Lazzari-Dean JR, Settineri NS, Kong EJ, Kramer RH, Miller EW. Voltage Imaging with a NIR-Absorbing Phosphine Oxide Rhodamine Voltage Reporter. J Am Chem Soc 2021; 143:2304-2314. [PMID: 33501825 PMCID: PMC7986050 DOI: 10.1021/jacs.0c11382] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The development of fluorescent dyes that emit and absorb light at wavelengths greater than 700 nm and that respond to biochemical and biophysical events in living systems remains an outstanding challenge for noninvasive optical imaging. Here, we report the design, synthesis, and application of near-infrared (NIR)-absorbing and -emitting optical voltmeter based on a sulfonated, phosphine-oxide (po) rhodamine for voltage imaging in intact retinas. We find that po-rhodamine based voltage reporters, or poRhoVRs, display NIR excitation and emission profiles at greater than 700 nm, show a range of voltage sensitivities (13 to 43% ΔF/F per 100 mV in HEK cells), and can be combined with existing optical sensors, like Ca2+-sensitive fluorescent proteins (GCaMP), and actuators, like light-activated opsins ChannelRhodopsin-2 (ChR2). Simultaneous voltage and Ca2+ imaging reveals differences in activity dynamics in rat hippocampal neurons, and pairing poRhoVR with blue-light based ChR2 affords all-optical electrophysiology. In ex vivo retinas isolated from a mouse model of retinal degeneration, poRhoVR, together with GCaMP-based Ca2+ imaging and traditional multielectrode array (MEA) recording, can provide a comprehensive physiological activity profile of neuronal activity, revealing differences in voltage and Ca2+ dynamics within hyperactive networks of the mouse retina. Taken together, these experiments establish that poRhoVR will open new horizons in optical interrogation of cellular and neuronal physiology in intact systems.
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Affiliation(s)
- Monica A. Gonzalez
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Alison S. Walker
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Department of Helen Wills Neuroscience Institute. University of California, Berkeley, California 94720, United States
| | - Kevin J. Cao
- Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, United States
| | - Julia R. Lazzari-Dean
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Nicholas S. Settineri
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Eui Ju Kong
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Richard H. Kramer
- Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, United States
- Department of Helen Wills Neuroscience Institute. University of California, Berkeley, California 94720, United States
| | - Evan W. Miller
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, United States
- Department of Helen Wills Neuroscience Institute. University of California, Berkeley, California 94720, United States
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23
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Olson JE, Hu Z, Best MD, Jensen L, Camden JP. Surface-enhanced hyper-Raman scattering of Rhodamine 6G isotopologues: Assignment of lower vibrational frequencies. J Chem Phys 2021; 154:034703. [PMID: 33499640 DOI: 10.1063/5.0031679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We report a comprehensive experimental and theoretical study of the lower-wavenumber vibrational modes in the surface-enhanced hyper-Raman scattering (SEHRS) of Rhodamine 6G (R6G) and its isotopologue R6G-d4. Measurements acquired on-resonance with two different electronic states, S1 and S2, are compared to the time-dependent density functional theory computations of the resonance hyper-Raman spectra and electrodynamics-quantum mechanical computations of the SEHRS spectra on-resonance with S1 and S2. After accounting for surface orientation, we find excellent agreement between experiment and theory for both R6G and its isotopologue. We then present a detailed analysis of the complex vibronic coupling effects in R6G and the importance of surface orientation for characterizing the system. This combination of theory and experiment allows, for the first time, an unambiguous assignment of lower-wavenumber vibrational modes of R6G and its isotopologue R6G-d4.
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Affiliation(s)
- Jacob E Olson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA
| | - Zhongwei Hu
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802-4615, USA
| | - Michael D Best
- Department of Chemistry, University of Tennessee, 1420 Circle Drive, Knoxville, Tennessee 37996, USA
| | - Lasse Jensen
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802-4615, USA
| | - Jon P Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA
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24
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Kato T, Strakova K, García-Calvo J, Sakai N, Matile S. Mechanosensitive Fluorescent Probes, Changing Color Like Lobsters during Cooking: Cascade Switching Variations. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2020. [DOI: 10.1246/bcsj.20200157] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Takehiro Kato
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Karolina Strakova
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - José García-Calvo
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Naomi Sakai
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Stefan Matile
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
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25
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Wang S, Li B, Zhang F. Molecular Fluorophores for Deep-Tissue Bioimaging. ACS CENTRAL SCIENCE 2020; 6:1302-1316. [PMID: 32875073 PMCID: PMC7453417 DOI: 10.1021/acscentsci.0c00544] [Citation(s) in RCA: 114] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Indexed: 05/08/2023]
Abstract
Fluorescence imaging has made tremendous inroads toward understanding the complexity of biological systems, but in vivo deep-tissue imaging remains a great challenge due to the optical opacity of biological tissue. Recent improvements in laser and detector manufacturing have allowed the expansion of nonlinear and linear fluorescence imaging to the underexplored "tissue-transparent" second near-infrared (NIR-II; 1000-1700 nm) window, opening up new opportunities for optical access deep inside opaque tissue. Molecular fluorophores have historically played a major role in fluorescence bioimaging. It is increasingly important to design new molecular fluorophores to fully unlock the potential of NIR-II imaging techniques. In this outlook, we give an overview of the novel molecular fluorophores developed for deep-tissue bioimaging in the past five years and discuss their pros and cons in applications. Guidelines for designing new molecular fluorophores with the desirable properties are also provided.
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Affiliation(s)
| | | | - Fan Zhang
- Department of Chemistry,
State Key Laboratory of Molecular Engineering of Polymers, Shanghai
Key Laboratory of Molecular Catalysis and Innovative Materials and
iChem, Fudan University, Shanghai 200433, P. R. China
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26
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Bruemmer KJ, Crossley SWM, Chang CJ. Activity-Based Sensing: A Synthetic Methods Approach for Selective Molecular Imaging and Beyond. Angew Chem Int Ed Engl 2020; 59:13734-13762. [PMID: 31605413 PMCID: PMC7665898 DOI: 10.1002/anie.201909690] [Citation(s) in RCA: 144] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Indexed: 01/10/2023]
Abstract
Emerging from the origins of supramolecular chemistry and the development of selective chemical receptors that rely on lock-and-key binding, activity-based sensing (ABS)-which utilizes molecular reactivity rather than molecular recognition for analyte detection-has rapidly grown into a distinct field to investigate the production and regulation of chemical species that mediate biological signaling and stress pathways, particularly metal ions and small molecules. Chemical reactions exploit the diverse chemical reactivity of biological species to enable the development of selective and sensitive synthetic methods to decipher their contributions within complex living environments. The broad utility of this reaction-driven approach facilitates application to imaging platforms ranging from fluorescence, luminescence, photoacoustic, magnetic resonance, and positron emission tomography modalities. ABS methods are also being expanded to other fields, such as drug and materials discovery.
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Affiliation(s)
- Kevin J Bruemmer
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Steven W M Crossley
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Christopher J Chang
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, 94720, USA
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27
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Liu Y, Lu Y, Chen G, Wang Q. Recent Progress of Hybrid Optical Probes for Neural Membrane Potential Imaging. Biotechnol J 2020; 15:e2000086. [PMID: 32662937 DOI: 10.1002/biot.202000086] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/04/2020] [Indexed: 12/17/2022]
Abstract
The neural membrane potential of nerve cells is the basis of neural activity production, which controls advanced brain activities such as memory, emotion, and learning. In the past decades, optical voltage indicator has emerged as a promising tool to decode neural activities with high-fidelity and excellent spatiotemporal resolution. In particular, the hybrid optical probes can combine the advantageous photophysical properties of different components such as voltage-sensitive molecules, highly fluorescent fluorophores, membrane-targeting tags, and optogenetic materials, thus showing numerous advantages in improving the photoluminescence intensity, voltage sensitivity, photostability, and cell specificity of probes. In this review, the current state-of-the-art hybrid probes are highlighted, that are designed by using fluorescent proteins, organic dyes, and fluorescent nanoprobes as the fluorophores, respectively. Then, the design strategies, voltage-sensing mechanisms and the in vitro and in vivo neural activity imaging applications of the hybrid probes are summarized. Finally, based on the current achievements of voltage imaging studies, the challenges and prospects for design and application of hybrid optical probes in the future are presented.
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Affiliation(s)
- Yongyang Liu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Yaxin Lu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Guangcun Chen
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China
| | - Qiangbin Wang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, 230026, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China.,College of Materials Sciences and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
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28
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Fiala T, Wang J, Dunn M, Šebej P, Choi SJ, Nwadibia EC, Fialova E, Martinez DM, Cheetham CE, Fogle KJ, Palladino MJ, Freyberg Z, Sulzer D, Sames D. Chemical Targeting of Voltage Sensitive Dyes to Specific Cells and Molecules in the Brain. J Am Chem Soc 2020; 142:9285-9301. [PMID: 32395989 DOI: 10.1021/jacs.0c00861] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Voltage sensitive fluorescent dyes (VSDs) are important tools for probing signal transduction in neurons and other excitable cells. The impact of these highly lipophilic sensors has, however, been limited due to the lack of cell-specific targeting methods in brain tissue or living animals. We address this key challenge by introducing a nongenetic molecular platform for cell- and molecule-specific targeting of synthetic VSDs in the brain. We employ a dextran polymer particle to overcome the inherent lipophilicity of VSDs by dynamic encapsulation and high-affinity ligands to target the construct to specific neuronal cells utilizing only native components of the neurotransmission machinery at physiological expression levels. Dichloropane, a monoamine transporter ligand, enables targeting of dense dopaminergic axons in the mouse striatum and sparse noradrenergic axons in the mouse cortex in acute brain slices. PFQX in conjunction with ligand-directed acyl imidazole chemistry enables covalent labeling of AMPA-type glutamate receptors in the same brain regions. Probe variants bearing either a classical electrochromic ANEP dye or state-of-the-art VoltageFluor-type dye respond to membrane potential changes in a similar manner to the parent dyes, as shown by whole-cell patch recording. We demonstrate the feasibility of optical voltage recording with our probes in brain tissue with one-photon and two-photon fluorescence microscopy and define the signal limits of optical voltage imaging with synthetic sensors under a low photon budget determined by the native expression levels of the target proteins. This work demonstrates the feasibility of a chemical targeting approach and expands the possibilities of cell-specific imaging and pharmacology.
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Affiliation(s)
- Tomas Fiala
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Jihang Wang
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Matthew Dunn
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Peter Šebej
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Se Joon Choi
- Department of Psychiatry, Columbia University Irving Medical Center, New York, New York 10027, United States
| | - Ekeoma C Nwadibia
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Eva Fialova
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Diana M Martinez
- Department of Psychiatry, Columbia University Irving Medical Center, New York, New York 10027, United States
| | - Claire E Cheetham
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Keri J Fogle
- Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.,Pittsburgh Institute of Neurodegenerative Diseases (PIND), University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Michael J Palladino
- Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.,Pittsburgh Institute of Neurodegenerative Diseases (PIND), University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Zachary Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States.,Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - David Sulzer
- Department of Psychiatry, Columbia University Irving Medical Center, New York, New York 10027, United States.,Department of Psychiatry, Columbia University Irving Medical Center, New York, New York 10027, United States.,Department of Pharmacology, Columbia University Irving Medical Center, New York, New York 10027, United States.,Department of Molecular Therapeutics, New York Psychiatric Institute, New York, New York 10032, United States
| | - Dalibor Sames
- Department of Chemistry, Columbia University, New York, New York 10027, United States.,NeuroTechnology Center at Columbia University, New York, New York 10027, United States
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29
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Bruemmer KJ, Crossley SWM, Chang CJ. Aktivitätsbasierte Sensorik: ein synthetisch‐methodischer Ansatz für die selektive molekulare Bildgebung und darüber hinaus. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201909690] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Kevin J. Bruemmer
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
| | | | - Christopher J. Chang
- Department of Chemistry University of California, Berkeley Berkeley CA 94720 USA
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute University of California, Berkeley Berkeley CA 94720 USA
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30
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Abstract
Membrane potential is a fundamental biophysical property maintained by every cell on earth. In specialized cells like neurons, rapid changes in membrane potential drive the release of chemical neurotransmitters. Coordinated, rapid changes in neuronal membrane potential across large numbers of interconnected neurons form the basis for all of human cognition, sensory perception, and memory. Despite the importance of this highly orchestrated and distributed activity, the traditional method for recording membrane potential is through the use of highly invasive single-cell electrodes that offer only a small glimpse of the total activity within a system. Fluorescent dyes that change their optical properties in response to changes in biological voltage have the potential to provide a powerful complement to traditional electrode-based methods of inquiry. Voltage-sensitive fluorescent indicators would allow the direct observation of membrane potential changes, significantly expanding our ability to monitor membrane potential dynamics in living systems. Toward this end, we have initiated a program to design, synthesize, and apply voltage-sensitive fluorophores that report on membrane potential dynamics with high sensitivity and speed. The basis for this optical voltage sensing is membrane potential-dependent photoinduced electron transfer (PeT). Voltage-sensitive fluorophores, or VoltageFluors, possess a fluorophore, a conjugated molecular wire, and an aniline donor. At resting potentials, in which the cell has a hyperpolarized or negative potential relative to the outside of the cell, PeT from the aniline donor is enhanced and fluorescence is diminished. At depolarized potentials, the membrane potential decreases the rate of PeT, allowing an increase in fluorescence. We show that a number of different fluorophores, molecular wires, and aniline donors can be employed to generate fast and sensitive VoltageFluor dyes. Multiple lines of evidence point to a PeT-based mechanism for voltage sensing, delivering fast response kinetics (∼25 ns), good sensitivity (>60% ΔF/F), compatibility with two-photon illumination, excellent signal-to-noise, and the ability to detect neuronal and cardiac action potentials in single trials. In this Account, we provide an overview of the challenges facing the design of fluorescent voltage indicators. We trace the development of molecular wire-based fluorescent voltage indicators within our group, beginning from fluorescein-based VoltageFluor to long-wavelength indicators that use modern fluorophores like silicon rhodamine and carbofluorescein. We examine design principles for PeT-based voltage indicators, showcase the use of our recent indicators for two-photon voltage imaging in intact brains, and explore the development of hybrid indicators that can localize to genetically defined cells. Finally, we highlight outstanding challenges to and opportunities for voltage imaging.
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Affiliation(s)
- Pei Liu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Evan W. Miller
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, United States
- Department of Helen Wills Neuroscience Institute. University of California, Berkeley, California 94720, United States
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31
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Deal PE, Liu P, Al-Abdullatif SH, Muller VR, Shamardani K, Adesnik H, Miller EW. Covalently Tethered Rhodamine Voltage Reporters for High Speed Functional Imaging in Brain Tissue. J Am Chem Soc 2020; 142:614-622. [PMID: 31829585 PMCID: PMC6949409 DOI: 10.1021/jacs.9b12265] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Voltage-sensitive fluorophores enable the direct visualization of membrane potential changes in living systems. To pair the speed and sensitivity of chemically synthesized fluorescent indicators with cell-type specific genetic methods, we here develop Rhodamine-based Voltage Reporters (RhoVR) that can be covalently tethered to genetically encoded, self-labeling enzymes. These chemical-genetic hybrids feature a photoinduced electron transfer triggered RhoVR voltage-sensitive indicator coupled to a chloroalkane HaloTag ligand through a long, water-soluble polyethylene glycol linker (RhoVR-Halo). When applied to cells, RhoVR-Halo dyes selectively and covalently bind to surface-expressed HaloTag enzyme on genetically modified cells. RhoVR-Halo dyes maintain high voltage sensitivities-up to 34% ΔF/F per 100 mV-and fast response times typical of untargeted RhoVRs, while gaining the selectivity of genetically encodable voltage indicators. We show that RhoVR-Halos can record action potentials in single trials from cultured rat hippocampal neurons and can be used in concert with green-fluorescent Ca2+ indicators like GCaMP to provide simultaneous voltage and Ca2+ imaging. In a brain slice, RhoVR-Halos provide exquisite labeling of defined cells and can be imaged using epifluorescence, confocal, or two-photon microscopy. Using high-speed epifluorescence microscopy, RhoVR-Halos provide a read-out of action potentials from labeled cortical neurons in a rat brain slice, without the need for trial averaging. These results demonstrate the potential of hybrid chemical-genetic voltage indicators to combine the optical performance of small-molecule chromophores with the inherent selectivity of genetically encodable systems, permitting imaging modalities inaccessible to either technique individually.
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Affiliation(s)
- Parker E. Deal
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Pei Liu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Sarah H. Al-Abdullatif
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Vikram R. Muller
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Kiarash Shamardani
- Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, United States
- Helen Wills Neuroscience Institute. University of California, Berkeley, California 94720, United States
| | - Hillel Adesnik
- Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, United States
- Helen Wills Neuroscience Institute. University of California, Berkeley, California 94720, United States
| | - Evan W. Miller
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Department of Molecular & Cell Biology, University of California, Berkeley, California 94720, United States
- Helen Wills Neuroscience Institute. University of California, Berkeley, California 94720, United States
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32
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Zhang X, Sakai N, Matile S. Methyl Scanning for Mechanochemical Chalcogen-Bonding Cascade Switches. ChemistryOpen 2020; 9:18-22. [PMID: 31921541 PMCID: PMC6946998 DOI: 10.1002/open.201900288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Indexed: 12/14/2022] Open
Abstract
Chalcogen-bonding cascade switching was introduced recently to produce the chemistry tools needed to image physical forces in biological systems. In the original flipper probe, one methyl group appeared to possibly interfere with the cascade switch. In this report, this questionable methyl group is replaced by a hydrogen. The deletion of this methyl group in planarizable push-pull probes was not trivial because it required the synthesis of dithienothiophenes with four different substituents on the four available carbons. The mechanosensitivity of the resulting demethylated flipper probe was nearly identical to that of the original. Thus methyl groups in the switching region are irrelevant for function, whereas those in the twisting region are essential. This result supports the chalcogen-bonding cascade switching concept and, most importantly, removes significant synthetic demands from future probe development.
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Affiliation(s)
- Xiang Zhang
- Department of Organic ChemistryUniversity of GenevaGenevaSwitzerland
| | - Naomi Sakai
- Department of Organic ChemistryUniversity of GenevaGenevaSwitzerland
| | - Stefan Matile
- Department of Organic ChemistryUniversity of GenevaGenevaSwitzerland
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33
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Levin M, Selberg J, Rolandi M. Endogenous Bioelectrics in Development, Cancer, and Regeneration: Drugs and Bioelectronic Devices as Electroceuticals for Regenerative Medicine. iScience 2019; 22:519-533. [PMID: 31837520 PMCID: PMC6920204 DOI: 10.1016/j.isci.2019.11.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/15/2019] [Accepted: 11/12/2019] [Indexed: 12/21/2022] Open
Abstract
A major frontier in the post-genomic era is the investigation of the control of coordinated growth and three-dimensional form. Dynamic remodeling of complex organs in regulative embryogenesis, regeneration, and cancer reveals that cells and tissues make decisions that implement complex anatomical outcomes. It is now essential to understand not only the genetics that specifies cellular hardware but also the physiological software that implements tissue-level plasticity and robust morphogenesis. Here, we review recent discoveries about the endogenous mechanisms of bioelectrical communication among non-neural cells that enables them to cooperate in vivo. We discuss important advances in bioelectronics, as well as computational and pharmacological tools that are enabling the taming of biophysical controls toward applications in regenerative medicine and synthetic bioengineering.
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Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA.
| | - John Selberg
- Electrical and Computer Engineering Department, University of California, Santa Cruz, CA 95064, USA
| | - Marco Rolandi
- Electrical and Computer Engineering Department, University of California, Santa Cruz, CA 95064, USA
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34
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Caglar M, Pandya R, Xiao J, Foster SK, Divitini G, Chen RYS, Greenham NC, Franze K, Rao A, Keyser UF. All-Optical Detection of Neuronal Membrane Depolarization in Live Cells Using Colloidal Quantum Dots. NANO LETTERS 2019; 19:8539-8549. [PMID: 31686516 PMCID: PMC7007274 DOI: 10.1021/acs.nanolett.9b03026] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 11/05/2019] [Indexed: 05/30/2023]
Abstract
Luminescent semiconductor quantum dots (QDs) have recently been suggested as novel probes for imaging and sensing cell membrane voltages. However, a key bottleneck for their development is a lack of techniques to assess QD responses to voltages generated in the aqueous electrolytic environments typical of biological systems. Even more generally, there have been relatively few efforts to assess the response of QDs to voltage changes in live cells. Here, we develop a platform for monitoring the photoluminescence (PL) response of QDs under AC and DC voltage changes within aqueous ionic environments. We evaluate both traditional CdSe/CdS and more biologically compatible InP/ZnS QDs at a range of ion concentrations to establish their PL/voltage characteristics on chip. Wide-field, few-particle PL measurements with neuronal cells show the QDs can be used to track local voltage changes with greater sensitivity (ΔPL up to twice as large) than state-of-the-art calcium imaging dyes, making them particularly appealing for tracking subthreshold events. Additional physiological observation studies showed that while CdSe/CdS dots have greater PL responses on membrane depolarization, their lower cytotoxicity makes InP/ZnS far more suitable for voltage sensing in living systems. Our results provide a methodology for the rational development of QD voltage sensors and highlight their potential for imaging changes in cell membrane voltage.
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Affiliation(s)
- Mustafa Caglar
- Department
of Physics, Cavendish Laboratory, University
of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Raj Pandya
- Department
of Physics, Cavendish Laboratory, University
of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - James Xiao
- Department
of Physics, Cavendish Laboratory, University
of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Sarah K. Foster
- Department
of Physiology, Development, and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, United Kingdom
| | - Giorgio Divitini
- Department
of Materials Science and Metallurgy, University
of Cambridge, Cambridge CB3 0FS, United Kingdom
| | - Richard Y. S. Chen
- Department
of Physics, Cavendish Laboratory, University
of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Neil C. Greenham
- Department
of Physics, Cavendish Laboratory, University
of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Kristian Franze
- Department
of Physiology, Development, and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, United Kingdom
| | - Akshay Rao
- Department
of Physics, Cavendish Laboratory, University
of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Ulrich F. Keyser
- Department
of Physics, Cavendish Laboratory, University
of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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35
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Macchione M, Goujon A, Strakova K, Humeniuk HV, Licari G, Tajkhorshid E, Sakai N, Matile S. A Chalcogen-Bonding Cascade Switch for Planarizable Push-Pull Probes. Angew Chem Int Ed Engl 2019; 58:15752-15756. [PMID: 31539191 PMCID: PMC7035594 DOI: 10.1002/anie.201909741] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Indexed: 11/08/2022]
Abstract
Planarizable push-pull probes have been introduced to demonstrate physical forces in biology. However, the donors and acceptors needed to polarize mechanically planarized probes are incompatible with their twisted resting state. The objective of this study was to overcome this "flipper dilemma" with chalcogen-bonding cascade switches that turn on donors and acceptors only in response to mechanical planarization of the probe. This concept is explored by molecular dynamics simulations as well as chemical double-mutant cycle analysis. Cascade switched flipper probes turn out to excel with chemical stability, red shifts adding up to high significance, and focused mechanosensitivity. Most important, however, is the introduction of a new, general and fundamental concept that operates with non-trivial supramolecular chemistry, solves an important practical problem and opens a wide chemical space.
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Affiliation(s)
- Mariano Macchione
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Antoine Goujon
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Karolina Strakova
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Heorhii V Humeniuk
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Giuseppe Licari
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology and Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology and Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Naomi Sakai
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Stefan Matile
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
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Strakova K, Poblador‐Bahamonde AI, Sakai N, Matile S. Fluorescent Flipper Probes: Comprehensive Twist Coverage. Chemistry 2019; 25:14935-14942. [DOI: 10.1002/chem.201903604] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/01/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Karolina Strakova
- Department of Organic ChemistryUniversity of Geneva Geneva Switzerland
| | | | - Naomi Sakai
- Department of Organic ChemistryUniversity of Geneva Geneva Switzerland
| | - Stefan Matile
- Department of Organic ChemistryUniversity of Geneva Geneva Switzerland
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Macchione M, Goujon A, Strakova K, Humeniuk HV, Licari G, Tajkhorshid E, Sakai N, Matile S. A Chalcogen‐Bonding Cascade Switch for Planarizable Push–Pull Probes. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201909741] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Mariano Macchione
- Department of Organic Chemistry University of Geneva Geneva Switzerland
| | - Antoine Goujon
- Department of Organic Chemistry University of Geneva Geneva Switzerland
| | - Karolina Strakova
- Department of Organic Chemistry University of Geneva Geneva Switzerland
| | | | - Giuseppe Licari
- NIH Center for Macromolecular Modeling and Bioinformatics Beckman Institute for Advanced Science and Technology and Department of Biochemistry University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics Beckman Institute for Advanced Science and Technology and Department of Biochemistry University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Naomi Sakai
- Department of Organic Chemistry University of Geneva Geneva Switzerland
| | - Stefan Matile
- Department of Organic Chemistry University of Geneva Geneva Switzerland
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Ortiz G, Liu P, Naing SHH, Muller VR, Miller EW. Synthesis of Sulfonated Carbofluoresceins for Voltage Imaging. J Am Chem Soc 2019; 141:6631-6638. [PMID: 30978010 DOI: 10.1021/jacs.9b01261] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We present the design, synthesis, and applications of a new class of voltage-sensitive fluorescent indicators built on a modified carbofluorescein scaffold. Carbofluoresceins are an attractive target for responsive probes because they maintain oxygen substitution patterns at the 3' and 6' positions, similar to fluorescein, while simultaneously possessing excitation and emission profiles red-shifted nearly 50 nm compared to fluorescein. However, the high p Ka of carbofluorescein dyes, coupled with their tendency to cyclize to nonfluorescent configurations, precludes their use in voltage-imaging applications. Here, we overcome the limitations of carbofluoresceins via chlorination to lower the p Ka by 2 units to 5.2 and sulfonation to prevent cyclization to the nonabsorbing form. To achieve this, we devise a synthetic route to halogenated sulfonated carbofluoresceins from readily available, inexpensive starting materials. New, chlorinated sulfone carbofluoresceins have low p Ka values (5.2) and can be incorporated into phenylenevinylene molecular wire scaffolds to create carboVoltage-sensitive fluorophores (carboVF dyes). The best of the new carboVF dyes, carboVF2.1(OMe).Cl, possesses excitation and emission profiles of >560 nm, displays high voltage sensitivity (>30% Δ F/ F per 100 mV), and can be used in the presence of other blue-excited fluorophores such as green fluorescent protein. Because carboVF2.1(OMe).Cl contains a phenolic oxygen, it can be incorporated into fluorogenic labeling strategies. Alkylation with a sterically bulky cyclopropylmethyl-derived acetoxymethyl ether renders carboVF weakly fluorescent; we show that fluorescence can be restored by the action of porcine liver esterase both in vitro and on the surface of living cells and neurons. Together, these results suggest chlorinated sulfone carbofluoresceins can be promising candidates for hybrid chemical-genetic voltage imaging at wavelengths beyond typical fluorescein excitation and emission.
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Advances in Engineering and Application of Optogenetic Indicators for Neuroscience. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9030562] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Our ability to investigate the brain is limited by available technologies that can record biological processes in vivo with suitable spatiotemporal resolution. Advances in optogenetics now enable optical recording and perturbation of central physiological processes within the intact brains of model organisms. By monitoring key signaling molecules noninvasively, we can better appreciate how information is processed and integrated within intact circuits. In this review, we describe recent efforts engineering genetically-encoded fluorescence indicators to monitor neuronal activity. We summarize recent advances of sensors for calcium, potassium, voltage, and select neurotransmitters, focusing on their molecular design, properties, and current limitations. We also highlight impressive applications of these sensors in neuroscience research. We adopt the view that advances in sensor engineering will yield enduring insights on systems neuroscience. Neuroscientists are eager to adopt suitable tools for imaging neural activity in vivo, making this a golden age for engineering optogenetic indicators.
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