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Mo Y, Xu J, Zhou H, Zhao Y, Chen K, Zhang J, Deng L, Zhang S. A machine learning-assisted fluorescent sensor array utilizing silver nanoclusters for coffee discrimination. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 322:124760. [PMID: 38959644 DOI: 10.1016/j.saa.2024.124760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 06/04/2024] [Accepted: 06/28/2024] [Indexed: 07/05/2024]
Abstract
Coffee is a globally consumed commodity of substantial commercial significance. In this study, we constructed a fluorescent sensor array based on two types of polymer templated silver nanoclusters (AgNCs) for the detection of organic acids and coffees. The nanoclusters exhibited different interactions with organic acids and generated unique fluorescence response patterns. By employing principal component analysis (PCA) and random forest (RF) algorithms, the sensor array exhibited good qualitative and quantitative capabilities for organic acids. Then the sensor array was used to distinguish coffees with different processing methods or roast degrees and the recognition accuracy achieved 100%. It could also successfully identify 40 coffee samples from 12 geographical origins. Moreover, it demonstrated another satisfactory performance for the classification of pure coffee samples with their binary and ternary mixtures or other beverages. In summary, we present a novel method for detecting and identifying multiple coffees, which has considerable potential in applications such as quality control and identification of fake blended coffees.
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Affiliation(s)
- Yidan Mo
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Jinming Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Huangmei Zhou
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Yu Zhao
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Kai Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Jie Zhang
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Lunhua Deng
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China.
| | - Sanjun Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China; NYU-ECNU Institute of Physics at NYU Shanghai, No.3663, North Zhongshan Rd., Shanghai 200062, China.
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2
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Peng W, Zhou JW, Li ML, Sun L, Zhang YJ, Li JF. Construction of nanoparticle-on-mirror nanocavities and their applications in plasmon-enhanced spectroscopy. Chem Sci 2024; 15:2697-2711. [PMID: 38404398 PMCID: PMC10882497 DOI: 10.1039/d3sc05722d] [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: 10/26/2023] [Accepted: 01/11/2024] [Indexed: 02/27/2024] Open
Abstract
Plasmonic nanocavities exhibit exceptional capabilities in visualizing the internal structure of a single molecule at sub-nanometer resolution. Among these, an easily manufacturable nanoparticle-on-mirror (NPoM) nanocavity is a successful and powerful platform for demonstrating various optical phenomena. Exciting advances in surface-enhanced spectroscopy using NPoM nanocavities have been developed and explored, including enhanced Raman, fluorescence, phosphorescence, upconversion, etc. This perspective emphasizes the construction of NPoM nanocavities and their applications in achieving higher enhancement capabilities or spatial resolution in dark-field scattering spectroscopy and plasmon-enhanced spectroscopy. We describe a systematic framework that elucidates how to meet the requirements for studying light-matter interactions through the creation of well-designed NPoM nanocavities. Additionally, it provides an outlook on the challenges, future development directions, and practical applications in the field of plasmon-enhanced spectroscopy.
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Affiliation(s)
- Wei Peng
- College of Energy, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China
| | - Jing-Wen Zhou
- College of Energy, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China
| | - Mu-Lin Li
- College of Energy, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China
| | - Lan Sun
- College of Energy, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China
| | - Yue-Jiao Zhang
- College of Energy, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China
| | - Jian-Feng Li
- College of Energy, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China
- College of Chemistry, Chemical Engineering and Environment, Minnan Normal University Zhangzhou 363000 China
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3
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Xu J, Chen X, Zhou H, Zhao Y, Cheng Y, Wu Y, Zhang J, Chen J, Zhang S. Machine learning-assisted photoluminescent sensor array based on gold nanoclusters for the discrimination of antibiotics with test paper. Talanta 2024; 266:125122. [PMID: 37651910 DOI: 10.1016/j.talanta.2023.125122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 09/02/2023]
Abstract
Antibiotic residues accumulation in the environment endangers ecosystems and human health. There is an urgent need for a facile and efficient strategy to detect antibiotics. Here, we report a photoluminescent sensor array based on protein-stabilized gold nanoclusters (AuNCs) for the detection of two families of antibiotics, tetracyclines and quinolones. The nanoclusters were synthesized with bovine serum albumin (BSA) and ovalbumin (OVA), respectively. They had different interactions with seven kinds of antibiotics and exhibited diverse photoluminescence (PL) responses, which were analyzed by linear discriminant analysis and ExtraTrees algorithms. The sensor array performed well in both classification and quantification of seven antibiotics. And the quantitative results of all antibiotics obtained R2 of no less than 0.99 at 0-100 μM when using suitable regression models. Additionally, the sensor array was able to distinguish antibiotic mixtures and multiple interfering substances, and it also kept 100% classification accuracy in river water samples. Moreover, test paper assisted by a smartphone was applied for quick detection of antibiotics, with good performance in both HEPES buffer and river water. These studies reveal great potential for the point-of-use analysis of antibiotics in environmental monitoring.
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Affiliation(s)
- Jinming Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai, 200241, China
| | - Xihang Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai, 200241, China
| | - Huangmei Zhou
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai, 200241, China
| | - Yu Zhao
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai, 200241, China
| | - Yuchi Cheng
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai, 200241, China
| | - Ying Wu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, No.500, Dongchuan Rd., Shanghai, 200241, China.
| | - Jie Zhang
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai, 200241, China
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai, 200241, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi, 030006, China
| | - Sanjun Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai, 200241, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi, 030006, China; NYU-ECNU Institute of Physics at NYU Shanghai, No.3663, North Zhongshan Rd., Shanghai, 200062, China.
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4
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Netaev A, Schierbaum N, Seidl K. Artificial Neural Network (ANN)-Based Determination of Fractional Contributions from Mixed Fluorophores using Fluorescence Lifetime Measurements. J Fluoresc 2024; 34:305-311. [PMID: 37212979 PMCID: PMC10808714 DOI: 10.1007/s10895-023-03261-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/04/2023] [Indexed: 05/23/2023]
Abstract
Here we present an artificial neural network (ANN)-approach to determine the fractional contributions Pi from fluorophores to a multi-exponential fluorescence decay in time-resolved lifetime measurements. Conventionally, Pi are determined by extracting two parameters (amplitude and lifetime) for each underlying mono-exponential decay using non-linear fitting. However, in this case parameter estimation is highly sensitive to initial guesses and weighting. In contrast, the ANN-based approach robustly gives the Pi without knowledge of amplitudes and lifetimes. By experimental measurements and Monte-Carlo simulations, we comprehensively show that accuracy and precision of Pi determination with ANNs and hence the number of distinguishable fluorophores depend on the fluorescence lifetimes' differences. For mixtures of up to five fluorophores, we determined the minimum uniform spacing Δτmin between lifetimes to obtain fractional contributions with a standard deviation of 5%. In example, five lifetimes can be distinguished with a respective minimum uniform spacing of approx. 10 ns even when the fluorophores' emission spectra are overlapping. This study underlines the enormous potential of ANN-based analysis for multi-fluorophore applications in fluorescence lifetime measurements.
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Affiliation(s)
- Alexander Netaev
- Fraunhofer Institute for Microelectronic Circuits and Systems, Finkenstr. 61, 47057, Duisburg, Germany.
| | - Nicolas Schierbaum
- Fraunhofer Institute for Microelectronic Circuits and Systems, Finkenstr. 61, 47057, Duisburg, Germany
| | - Karsten Seidl
- Fraunhofer Institute for Microelectronic Circuits and Systems, Finkenstr. 61, 47057, Duisburg, Germany
- Department of Electronic Components and Circuits and Center for Nanointegration Duisburg-Essen (CENIDE), University Duisburg-Essen, 47057, Duisburg, Germany
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5
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Thapa P, Bhatt S, Mishra D, Mehta DS. Effect of fluorescein dye concentration in oral cancer tissue: Statistical and spectroscopic analysis. Photodiagnosis Photodyn Ther 2023; 44:103889. [PMID: 37949386 DOI: 10.1016/j.pdpdt.2023.103889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/12/2023]
Abstract
Oral cancer screening with exogenous agents is highly demanding due to high sensitivity, as the early diagnosis plays a vital role in achieving favorable outcomes for oral squamous cell carcinomas (OSCC) by facilitating prompt detection and comprehensive surgical removal. Optical techniques utilizing the local application of fluorescein dye or fluorescence-guided surgery offer potential for early OSCC detection. The use of fluorescein dye in oral cancer is significantly less, and there is a need to inspect the local application of fluorescein dye in oral cancer patients. Concentration-based investigations of the dye with OSCC patients are essential to ensure accurate fluorescence-guided surgery and screening with fluorescein labeling and to mitigate possible adverse effects. Additionally, analyzing the dye distribution within OSCC tissues can provide insights into their heterogeneity, a critical indicator of malignancy. The present study includes a concentration-based statistical and spectroscopic analysis of fluorescein dye in ex-vivo and in-vivo OSCC patients. In the ex-vivo examination of OSCC tissues, five concentrations (18.66 ± 0.06, 9.51 ± 0.02, 6.38 ± 0.01, 4.80 ± 0.004, and 3.85 ± 0.002 millimolar) are employed for optical analysis. The ex-vivo OSCC tissues are analyzed for multiple statistical parameters at all concentrations, and the results are thoroughly described. Additionally, spectroscopic analysis is conducted on all concentrations for a comprehensive evaluation. Following optical analysis of all five concentrations in the ex-vivo study, two concentrations, 6.38 ± 0.01 and 4.80 ± 0.004 millimolar, are identified as suitable for conducting in-vivo investigations of oral cancer. A detailed spectroscopic and statistical study of OSCC tissues in-vivo has been done using these two concentrations.
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Affiliation(s)
- Pramila Thapa
- Bio-photonics and Green-photonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz-Khas, New Delhi 110016, India
| | - Sunil Bhatt
- Bio-photonics and Green-photonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz-Khas, New Delhi 110016, India
| | - Deepika Mishra
- Department of Oral Pathology and Microbiology, Center for Dental Education & Research, All India Institute of Medical Sciences (AIIMS), Ansari Nagar, New Delhi 110029, India
| | - Dalip Singh Mehta
- Bio-photonics and Green-photonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz-Khas, New Delhi 110016, India.
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6
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Duru J, Rüfenacht A, Löhle J, Pozzi M, Forró C, Ledermann L, Bernardi A, Matter M, Renia A, Simona B, Tringides CM, Bernhard S, Ihle SJ, Hengsteler J, Maurer B, Zhang X, Nakatsuka N. Driving electrochemical reactions at the microscale using CMOS microelectrode arrays. LAB ON A CHIP 2023; 23:5047-5058. [PMID: 37916299 PMCID: PMC10661664 DOI: 10.1039/d3lc00630a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 10/25/2023] [Indexed: 11/03/2023]
Abstract
Precise control of pH values at electrode interfaces enables the systematic investigation of pH-dependent processes by electrochemical means. In this work, we employed high-density complementary metal-oxide-semiconductor (CMOS) microelectrode arrays (MEAs) as miniaturized systems to induce and confine electrochemical reactions in areas corresponding to the pitch of single electrodes (17.5 μm). First, we present a strategy for generating localized pH patterns on the surface of the CMOS MEA with unprecedented spatial resolution. Leveraging the versatile routing capabilities of the switch matrix beneath the CMOS MEA, we created arbitrary combinations of anodic and cathodic electrodes and hence pH patterns. Moreover, we utilized the system to produce polymeric surface patterns by additive and subtractive methods. For additive patterning, we controlled the in situ formation of polydopamine at the microelectrode surface through oxidation of free dopamine above a threshold pH > 8.5. For subtractive patterning, we removed cell-adhesive poly-L-lysine from the electrode surface and backfilled the voids with antifouling polymers. Such polymers were chosen to provide a proof-of-concept application of controlling neuronal growth via electrochemically-induced patterns on the CMOS MEA surface. Importantly, our platform is compatible with commercially available high-density MEAs and requires no custom equipment, rendering the findings generalizable and accessible.
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Affiliation(s)
- Jens Duru
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Arielle Rüfenacht
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Josephine Löhle
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Marcello Pozzi
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Csaba Forró
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Linus Ledermann
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Aeneas Bernardi
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Michael Matter
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - André Renia
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | | | - Christina M Tringides
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Stéphane Bernhard
- Macromolecular Engineering Laboratory, Department of Mechanical and Process Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland
| | - Stephan J Ihle
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Julian Hengsteler
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Benedikt Maurer
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Xinyu Zhang
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
| | - Nako Nakatsuka
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Switzerland.
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7
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Wilda CB, Burnstock A, Suhling K, Mattioli Della Rocca F, Henderson RK, Nedbal J. Visualising varnish removal for conservation of paintings by fluorescence lifetime imaging (FLIM). HERITAGE SCIENCE 2023; 11:127. [PMID: 37333623 PMCID: PMC10276100 DOI: 10.1186/s40494-023-00957-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/17/2023] [Indexed: 06/20/2023]
Abstract
The removal of varnish from the surface is a key step in painting conservation. Varnish removal is traditionally monitored by examining the painting surface under ultraviolet illumination. We show here that by imaging the fluorescence lifetime instead, much better contrast, sensitivity, and specificity can be achieved. For this purpose, we developed a lightweight (4.8 kg) portable instrument for macroscopic fluorescence lifetime imaging (FLIM). It is based on a time-correlated single-photon avalanche diode (SPAD) camera to acquire the FLIM images and a pulsed 440 nm diode laser to excite the varnish fluorescence. A historical model painting was examined to demonstrate the capabilities of the system. We found that the FLIM images provided information on the distribution of the varnish on the painting surface with greater sensitivity, specificity, and contrast compared to the traditional ultraviolet illumination photography. The distribution of the varnish and other painting materials was assessed using FLIM during and after varnish removal with different solvent application methods. Monitoring of the varnish removal process between successive solvent applications by a swab revealed an evolving image contrast as a function of the cleaning progress. FLIM of dammar and mastic resin varnishes identified characteristic changes to their fluorescence lifetimes depending on their ageing conditions. Thus, FLIM has a potential to become a powerful and versatile tool to visualise varnish removal from paintings. Graphical Abstract
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Affiliation(s)
- Christine B. Wilda
- Department of Physics, King’s College London, Strand, London, WC2R 2LS United Kingdom
- The Courtauld, Somerset House, Strand, London, WC1X 0RN United Kingdom
- ConservArt, 6620 E Rogers Cir, Boca Raton, FL 33487 United States
| | - Aviva Burnstock
- The Courtauld, Somerset House, Strand, London, WC1X 0RN United Kingdom
| | - Klaus Suhling
- Department of Physics, King’s College London, Strand, London, WC2R 2LS United Kingdom
| | - Francesco Mattioli Della Rocca
- School of Engineering, University of Edinburgh, King’s Buildings, Edinburgh, EH9 3JL United Kingdom
- Europe Technology Development Centre, Sony Semiconductor Solutions - Sony Europe B.V., Trento, Italy
| | - Robert K. Henderson
- School of Engineering, University of Edinburgh, King’s Buildings, Edinburgh, EH9 3JL United Kingdom
| | - Jakub Nedbal
- Department of Physics, King’s College London, Strand, London, WC2R 2LS United Kingdom
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8
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Guzmán-Méndez Ó, Reza MM, Meza B, Jara-Cortés J, Peón J. Solvent Effects on the Singlet-Triplet Couplings in Nitroaromatic Compounds. J Phys Chem B 2023. [PMID: 37327487 DOI: 10.1021/acs.jpcb.3c01143] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Nitrated polycyclic molecules can present the largest singlet-triplet crossing rates among organic molecules. This implies that most of these compounds have no detectable steady-state fluorescence. In addition, some nitroaromatics undergo a complex series of photoinduced atom rearrangements that result in nitric oxide dissociation. The overall photochemistry of these systems depends critically on the competition between the rapid intersystem crossing channel and other excited-state pathways. In this contribution, we sought to characterize the degree of stabilization of the S1 state due to solute-solvent interactions, and to quantify the effect of such stabilization on their photophysical pathways. We studied 2- and 4-nitropyrene (2-NP and 4-NP), which are atypically emissive nitroaromatics in a series of solvents. From steady-state and time-resolved measurements, the S1 state of these molecules shows significant stabilization as the solvent polarity is increased. On the other hand, specific triplet states that are iso-energetic with the emissive singlet (T3 for 2-NP and T2 for 4-NP) in nonpolar solvents become slightly de-stabilized upon increasing the solvent polarity. These combined effects result in rapid singlet-triplet population transfer in nonpolar solvents for both molecules. In contrast, for solvents with even slightly higher polarities, the first excited singlet is stabilized in relation to the specific triplet states, leading to much longer S1 lifetimes. These effects can be summarized as a highly solvent-dependent coupling/decoupling of the manifolds. Similar effects are also likely to be present in other nitroaromatics where there is a dynamic competition between nitric oxide dissociation and intersystem crossing. The drastic effects of the solvent polarity in the manifold crossing pathway should be taken into consideration in both theoretical and experimental studies of nitroaromatics.
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Affiliation(s)
- Óscar Guzmán-Méndez
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510 Ciudad de México, México
| | - Mariana M Reza
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510 Ciudad de México, México
| | - Brandon Meza
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510 Ciudad de México, México
| | - Jesús Jara-Cortés
- Unidad Académica de Ciencias Básicas e Ingenierías, Universidad Autónoma de Nayarit, Tepic 63155, México
| | - Jorge Peón
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510 Ciudad de México, México
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9
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Morales-Moreno MD, Valdés-Galindo EG, Reza MM, Fiordelisio T, Peon J, Hernandez-Garcia A. Multiplex gRNAs Synergically Enhance Detection of SARS-CoV-2 by CRISPR-Cas12a. CRISPR J 2023; 6:116-126. [PMID: 36944123 DOI: 10.1089/crispr.2022.0074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023] Open
Abstract
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) diagnostic methods have a large potential to effectively detect SARS-CoV-2 with sensitivity and specificity nearing 100%, comparable to quantitative polymerase chain reaction. Yet, there is room for improvement. Commonly, one guide CRISPR RNA (gRNA) is used to detect the virus DNA and activate Cas collateral activity, which cleaves a reporter probe. In this study, we demonstrated that using 2-3 gRNAs in parallel can create a synergistic effect, resulting in a 4.5 × faster cleaving rate of the probe and increased sensitivity compared to using individual gRNAs. The synergy is due to the simultaneous activation of CRISPR-Cas12a and the improved performance of each gRNA. This approach was able to detect as few as 10 viral copies of the N-gene of SARS-CoV-2 RNA after a preamplification step using reverse transcription loop-mediated isothermal amplification. The method was able to accurately detect 100% of positive and negative clinical samples in ∼25 min using a fluorescence plate reader and ∼45 min with lateral flow strips.
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Affiliation(s)
- Melissa D Morales-Moreno
- Laboratory of Biomolecular Engineering and Bionanotechnology, Department of Chemistry of Biomacromolecules, Institute of Chemistry, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Erick G Valdés-Galindo
- Laboratory of Biomolecular Engineering and Bionanotechnology, Department of Chemistry of Biomacromolecules, Institute of Chemistry, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Mariana M Reza
- Department of Physical Chemistry, Institute of Chemistry, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Tatiana Fiordelisio
- Laboratorio de Neuroendocrinología Comparada, Laboratorio Nacional de Soluciones Biomiméticas para Diagnóstico y Terapia LaNSBioDyT, Faculty of Sciences, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Jorge Peon
- Department of Physical Chemistry, Institute of Chemistry, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Armando Hernandez-Garcia
- Laboratory of Biomolecular Engineering and Bionanotechnology, Department of Chemistry of Biomacromolecules, Institute of Chemistry, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
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10
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Xu J, Yuan H, Zhou H, Zhao Y, Wu Y, Zhang J, Zhang S. A novel fluorescent sensor array to identify Baijiu based on the single gold nanocluster probe. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 284:121787. [PMID: 36087404 DOI: 10.1016/j.saa.2022.121787] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/16/2022] [Accepted: 08/23/2022] [Indexed: 05/26/2023]
Abstract
Baijiu occupies a vital position in Chinese food and China's market. Strict evaluation of Baijiu is highly demanded. In this study, we constructed a novel fluorescent sensor array based on the single glutathione-protected gold nanoclusters (AuNCs) probe for the detection of organic acids and Baijiu. The fluorescence of AuNCs was simply modulated by three metal ions (Cu2+, Mn2+, and Ag+), and formed new complexes as sensing elements. These four sensing elements responded variously to nine organic acids, and further chemometric analysis results allowed for the classification and quantification of acids. Moreover, the sensor array successfully identified 21 Baijiu samples of different brands among 11 aroma types. It could also distinguish Baijiu of different qualities as well as pure Baijiu from its adulterations and showed high selectivity among multiple interfering drinks. The results demonstrated that the AuNCs-based sensor array has considerable potential for quality monitoring of Baijiu.
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Affiliation(s)
- Jinming Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd, Shanghai 200241, China
| | - Hao Yuan
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd, Shanghai 200241, China
| | - Huangmei Zhou
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd, Shanghai 200241, China
| | - Yu Zhao
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd, Shanghai 200241, China
| | - Ying Wu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, No.500, Dongchuan Rd, Shanghai 200241, China.
| | - Jie Zhang
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Sanjun Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd, Shanghai 200241, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China; NYU-ECNU Institute of Physics at NYU Shanghai, No.3663, North Zhongshan Rd, Shanghai 200062, China.
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11
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Martínez-Bourget D, Rocha E, Labra-Vázquez P, Santillan R, Ortiz-López B, Ortiz-Navarrete V, Maraval V, Chauvin R, Farfán N. BODIPY-Ethynylestradiol molecular rotors as fluorescent viscosity probes in endoplasmic reticulum. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 283:121704. [PMID: 35985231 DOI: 10.1016/j.saa.2022.121704] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/20/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
Due to their capability for sensing changes in viscosity, fluorescent molecular rotors (FMRs) have emerged as potential tools to develop several promising viscosity probes; most of them, however, localize non-selectively within cells, precluding changes in the viscosity of specific cellular microdomains to be studied by these means. Following previous reports on enhanced fluorophore uptake efficiency and selectivity by incorporation of biological submolecular fragments, here we report two potential BODIPY FMRs based on an ethynylestradiol spindle, a non-cytotoxic semisynthetic estrogen well recognized by human cells. A critical evaluation of the potential of these fluorophores for being employed as FMRs is presented, including the photophysical characterization of the probes, SXRD studies and TD-DFT computations, as well as confocal microscopy imaging in MCF-7 (breast cancer) cells.
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Affiliation(s)
- Diego Martínez-Bourget
- Facultad de Química, Departamento de Química Orgánica, Universidad Nacional Autónoma de México, Coyoacán 04510, CDMX, México
| | - Erika Rocha
- Facultad de Química, Departamento de Química Orgánica, Universidad Nacional Autónoma de México, Coyoacán 04510, CDMX, México
| | - Pablo Labra-Vázquez
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, 31077 Toulouse, France
| | - Rosa Santillan
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740, 07000, México
| | - Benjamín Ortiz-López
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, CINVESTAV, Apdo., Postal 14-740, México, D.F. 07000, Mexico
| | - Vianney Ortiz-Navarrete
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, CINVESTAV, Apdo., Postal 14-740, México, D.F. 07000, Mexico
| | - Valérie Maraval
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, 31077 Toulouse, France
| | - Remi Chauvin
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, 31077 Toulouse, France
| | - Norberto Farfán
- Facultad de Química, Departamento de Química Orgánica, Universidad Nacional Autónoma de México, Coyoacán 04510, CDMX, México.
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12
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The BrightEyes-TTM as an open-source time-tagging module for democratising single-photon microscopy. Nat Commun 2022; 13:7406. [PMID: 36456575 PMCID: PMC9715684 DOI: 10.1038/s41467-022-35064-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 11/09/2022] [Indexed: 12/03/2022] Open
Abstract
Fluorescence laser-scanning microscopy (LSM) is experiencing a revolution thanks to new single-photon (SP) array detectors, which give access to an entirely new set of single-photon information. Together with the blooming of new SP LSM techniques and the development of tailored SP array detectors, there is a growing need for (i) DAQ systems capable of handling the high-throughput and high-resolution photon information generated by these detectors, and (ii) incorporating these DAQ protocols in existing fluorescence LSMs. We developed an open-source, low-cost, multi-channel time-tagging module (TTM) based on a field-programmable gate array that can tag in parallel multiple single-photon events, with 30 ps precision, and multiple synchronisation events, with 4 ns precision. We use the TTM to demonstrate live-cell super-resolved fluorescence lifetime image scanning microscopy and fluorescence lifetime fluctuation spectroscopy. We expect that our BrightEyes-TTM will support the microscopy community in spreading SP-LSM in many life science laboratories.
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13
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Fauvel M, Trybala A, Tseluiko D, Starov VM, Bandulasena HCH. Foam-Based Electrophoretic Separation of Charged Dyes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13935-13942. [PMID: 36322953 PMCID: PMC9671044 DOI: 10.1021/acs.langmuir.2c02228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Electrophoretic separation of a fluorescent dye mixture, containing rhodamine B (RB) and fluorescein, in liquid foams stabilized by anionic, cationic, or non-ionic surfactants in water-glycerol mixtures was studied in a custom-designed foam separation device. The effects of the external electric field applied across the foam and the initial pH of the solution on the effectiveness of separation were also studied. The fluid motion due to electroosmosis and the resulting back pressure within the foam and local pH changes were found to be complex and affected the separation. Fluorescein dye molecules, which have a positive or negative charge depending on the solution pH, aggregated in the vicinity of an electrode, leaving a pure band of neutral dye RB. The effectiveness of the separation was quantified by the percentage width of the pure RB band, which was found to be between 29 and 42%. This study demonstrates the potential of liquid foam as a platform for electrophoretic separation.
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Affiliation(s)
- Matthieu Fauvel
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
| | - Anna Trybala
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
| | - Dmitri Tseluiko
- Department
of Mathematics, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
| | - Victor Mikhilovich Starov
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
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14
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Metal-Organic frameworks encapsulated Ag Nanoparticle-Nanoclusters with enhanced luminescence for simultaneous detection and removal of Chromium(VI). Microchem J 2022. [DOI: 10.1016/j.microc.2022.107722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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15
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Durán-Hernández J, Muñoz-Rugeles L, Guzmán-Méndez Ó, M Reza M, Cadena-Caicedo A, García-Montalvo V, Peón J. Sensitization of Nd 3+ Luminescence by Simultaneous Two-Photon Excitation through a Coordinating Polymethinic Antenna. J Phys Chem A 2022; 126:2498-2510. [PMID: 35436116 DOI: 10.1021/acs.jpca.2c01052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have designed and synthesized two new cyaninic Nd3+ complexes where the lanthanide emission can be induced from simultaneous two-photon absorption followed by energy migration. These complexes correspond to a molecular design that uses an antenna ligand formed by the functionalization of a heptamethine dye with 5-ol-phenanthroline or 4-phenyl-terpyridine derivatives. These complexes employ the important nonlinear optical properties of symmetric polymethines to sensitize the lanthanide ion. We verified that simultaneous biphotonic excitation indirectly induces the 4F3/2 → 4I11/2 Nd3+ emission using femtosecond laser pulses tuned below the first electronic transition of the antenna. The simultaneous two-photon excitation events initially form the nonlinear-active second excited singlet of the polymethine antenna, which rapidly evolves into its first excited singlet. This state in turn induces the formation of the emissive Nd3+ states through energy transfer. The role of the first excited singlet of the antenna as the donor state in this process was verified through time resolution of the antenna's fluorescence. These measurements also provided the rates for antenna-lanthanide energy transfer, which indicate that the phenanthroline-type ligand is approximately five times more efficient for energy transfer than the phenyl-terpyridine derivative due to their relative donor-acceptor distances. The simultaneous two-photon excitation of this polymethine antenna allows for high spatial localization of the Nd3+excitation events.
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Affiliation(s)
- Jesús Durán-Hernández
- Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Leonardo Muñoz-Rugeles
- Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Óscar Guzmán-Méndez
- Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Mariana M Reza
- Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Andrea Cadena-Caicedo
- Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | | | - Jorge Peón
- Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
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16
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Xu J, Zhou H, Zhang Y, Zhao Y, Yuan H, He X, Wu Y, Zhang S. Copper nanoclusters-based fluorescent sensor array to identify metal ions and dissolved organic matter. JOURNAL OF HAZARDOUS MATERIALS 2022; 428:128158. [PMID: 35016123 DOI: 10.1016/j.jhazmat.2021.128158] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/12/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
In recent years, the prevention and control of water pollution has received extensive attention. There is a need to develop simple and effective strategies for the rapid detection of metal ions and dissolved organic matter (DOM) in order to improve water quality. To this end, the first copper nanoclusters (CuNCs)-based fluorescent sensor array was done to identify 12 metal ions (Pb2+, Fe3+, Cu2+, Cd2+, Cr3+, Co2+, Ni2+, Zn2+, Ag+, Fe2+, Hg2+, and Al3+) and DOM (humic substances, lipids, fatty acids, amino acids, and lignans). The results revealed that CuNCs that were synthesized with polyethyleneimine (PEI), histidine (His), and glutathione (GSH) exhibited different binding abilities to metal ions and DOM. These unique fluorescence responses were analyzed using principal component analysis (PCA) and linear discriminant analysis (LDA) to identify metal ions and DOM in the buffer. The aforementioned 12 metal ions were classified at a limit concentration of 1.5 μM. Moreover, quantification of metal ions was achieved even at a low concentration of 0.83 μM (Zn2+). This array also worked well in the recognition of metal ions in tap water as well as distinguishing riverine and seawater samples of different regions, which was of great significance in environmental monitoring.
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Affiliation(s)
- Jinming Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Huangmei Zhou
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Yixue Zhang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Yu Zhao
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Hao Yuan
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Xiaoxiao He
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China
| | - Ying Wu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China.
| | - Sanjun Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No.500, Dongchuan Rd., Shanghai 200241, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China; NYU-ECNU Institute of Physics at NYU Shanghai, No.3663, North Zhongshan Rd., Shanghai 200062, China.
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17
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Optimisation of a lozenge-based sensor for detecting impending blockage of urinary catheters. Biosens Bioelectron 2022; 197:113775. [PMID: 34781179 DOI: 10.1016/j.bios.2021.113775] [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: 09/20/2021] [Revised: 11/02/2021] [Accepted: 11/05/2021] [Indexed: 11/20/2022]
Abstract
Catheter-associated urinary tract infections resulting from urease-positive microorganisms are more likely to cause a urinary catheter blockage owing to the urease activity of the microbes. Catheter blockage can be dangerous and increases the risk of severe infections, such as sepsis. Ureases, a virulence factor in Proteus mirabilis, cause an increase in urine pH - leading to blockage. An optimised biosensor "lozenge" is presented here, which is able to detect impending catheter blockage. This lozenge has been optimised to allow easy manufacture and commercialisation. It functions as a sensor in a physiologically representative model of a catheterised urinary tract, providing 6.7 h warning prior to catheter blockage. The lozenge is stable in healthy human urine and can be sterilized for clinical use by ethylene oxide. Clinically, the lozenge will provide a visible indication of impending catheter blockage, enabling quicker clinical intervention and thus reducing the morbidity and mortality associated with blockage.
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18
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Zhou H, Zhao Y, Chen X, Zhang S. Ultrafast Spectroscopic Studies of the pH responsive 9-Acridinecarboxylic Acid as a Ratiometric and Fluorescence Lifetime pH Indicator. Microchem J 2022. [DOI: 10.1016/j.microc.2022.107240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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19
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Zhao Z, Cao S, Li H, Li D, He Y, Wang X, Chen J, Zhang S, Xu J, Knutson JR. Ultrafast excited-state dynamics of thiazole orange. Chem Phys 2022; 553. [DOI: 10.1016/j.chemphys.2021.111392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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20
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Liao P, Zang S, Wu T, Jin H, Wang W, Huang J, Tang BZ, Yan Y. Generating circularly polarized luminescence from clusterization-triggered emission using solid phase molecular self-assembly. Nat Commun 2021; 12:5496. [PMID: 34535652 PMCID: PMC8448880 DOI: 10.1038/s41467-021-25789-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 08/19/2021] [Indexed: 02/08/2023] Open
Abstract
Purely-organic clusterization-triggered emission (CTE) has displayed promising abilities in bioimaging, chemical sensing, and multicolor luminescence. However, it remains absent in the field of circularly polarized luminescence (CPL) due to the difficulties in well-aligning the nonconventional luminogens. We report a case of CPL generated with CTE using the solid phase molecular self-assembly (SPMSA) of poly-L-lysine (PLL) and oleate ion (OL), that is, the macroscopic CPL supramolecular film self-assembled by the electrostatic complex of PLL/OL under mechanical pressure. Well-defined interface charge distribution, given by lamellar mesophases of OL ions, forces the PLL chains to fold regularly as a requirement of optimal electrostatic interactions. Further facilitated by hydrogen bonding, the through-space conjugation (TSC) of orderly aligned electron-rich O and N atoms leads to CTE-based CPL, which is capable of transferring energy to an acceptor via a Förster resonance energy transfer (FRET) process, making it possible to develop environmentally friendly and economic CPL from sustainable and renewable materials.
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Affiliation(s)
- Peilong Liao
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Shihao Zang
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Tongyue Wu
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Hongjun Jin
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Wenkai Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Jianbin Huang
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Ben Zhong Tang
- Shenzhen Institute of Molecular Aggregate Science and Engineering, School of Science and Engineering, The Chinese University of Hong Kong, 2001 Longxiang Boulevard, Longgang, Shenzhen, Guangdong, 518172, China.
| | - Yun Yan
- Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
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21
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Angulo G, Kardaś TM, Rodríguez-Rodríguez H. Some aspects about time broadening in fluorescence up-conversion measurements. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:063003. [PMID: 34243531 DOI: 10.1063/5.0047695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 06/05/2021] [Indexed: 06/13/2023]
Abstract
Several aspects contributing to the temporal broadening in the measurement of ultrafast fluorescence by means of up-conversion wave mixing are presented: the characteristics of the sample, those of the collection optics, and the wave mixing with the gate pulse in a non-linear crystal. It is concluded that these contributions are emission wavelength dependent and can be as important as the pulse durations in determining the instrument response function in this technique.
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Affiliation(s)
- Gonzalo Angulo
- Institute of Physical Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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22
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Seita A, Nakaoka H, Okura R, Wakamoto Y. Intrinsic growth heterogeneity of mouse leukemia cells underlies differential susceptibility to a growth-inhibiting anticancer drug. PLoS One 2021; 16:e0236534. [PMID: 33524064 PMCID: PMC7850478 DOI: 10.1371/journal.pone.0236534] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 01/14/2021] [Indexed: 11/18/2022] Open
Abstract
Cancer cell populations consist of phenotypically heterogeneous cells. Growing evidence suggests that pre-existing phenotypic differences among cancer cells correlate with differential susceptibility to anticancer drugs and eventually lead to a relapse. Such phenotypic differences can arise not only externally driven by the environmental heterogeneity around individual cells but also internally by the intrinsic fluctuation of cells. However, the quantitative characteristics of intrinsic phenotypic heterogeneity emerging even under constant environments and their relevance to drug susceptibility remain elusive. Here we employed a microfluidic device, mammalian mother machine, for studying the intrinsic heterogeneity of growth dynamics of mouse lymphocytic leukemia cells (L1210) across tens of generations. The generation time of this cancer cell line had a distribution with a long tail and a heritability across generations. We determined that a minority of cell lineages exist in a slow-cycling state for multiple generations. These slow-cycling cell lineages had a higher chance of survival than the fast-cycling lineages under continuous exposure to the anticancer drug Mitomycin C. This result suggests that heritable heterogeneity in cancer cells’ growth in a population influences their susceptibility to anticancer drugs.
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Affiliation(s)
- Akihisa Seita
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Hidenori Nakaoka
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- * E-mail: (HN); (YW)
| | - Reiko Okura
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuichi Wakamoto
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Research Center for Complex Systems Biology, The University of Tokyo, Tokyo, Japan
- Universal Biology Institute, The University of Tokyo, Tokyo, Japan
- * E-mail: (HN); (YW)
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23
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Cao N, Xu J, Zhou H, Zhao Y, Xu J, Li J, Zhang S. A fluorescent sensor array based on silver nanoclusters for identifying heavy metal ions. Microchem J 2020. [DOI: 10.1016/j.microc.2020.105406] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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24
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Zhou Y, Mowlazadeh Haghighi S, Liu Z, Wang L, Hruby VJ, Cai M. Development of Ligand-Drug Conjugates Targeting Melanoma through the Overexpressed Melanocortin 1 Receptor. ACS Pharmacol Transl Sci 2020; 3:921-930. [PMID: 33073191 DOI: 10.1021/acsptsci.0c00072] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Indexed: 12/31/2022]
Abstract
Melanoma is a lethal form of skin cancer. Despite recent breakthroughs of BRAF-V600E and PD-1 inhibitors showing remarkable clinical responses, melanoma can eventually survive these targeted therapies and become resistant. To solve the drug resistance issue, we designed and synthesized ligand-drug conjugates that couple cytotoxic drugs, which have a low cancer resistance issue, with the melanocortin 1 receptor (MC1R) agonist melanotan-II (MT-II), which provides specificity to MC1R-overexpressing melanoma. The drug-MT-II conjugates maintain strong binding interactions to MC1R and induce selective drug delivery to A375 melanoma cells through its MT-II moiety in vitro. Furthermore, using camptothecin as the cytotoxic drug, camptothecin-MT-II (compound 1) can effectively inhibit A375 melanoma cell growth with an IC50 of 16 nM. By providing selectivity to melanoma cells through its MT-II moiety, this approach of drug-MT-II conjugates enables us to have many more options for cytotoxic drug selection, which can be the key to solving the cancer resistant problem for melanoma.
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Affiliation(s)
- Yang Zhou
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
| | - Saghar Mowlazadeh Haghighi
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
| | - Zekun Liu
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
| | - Lingzhi Wang
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
| | - Victor J Hruby
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
| | - Minying Cai
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721, United States
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25
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Dai L, Liu J, Liang K, Yang R, Han D, Lu B. Realization of a time-correlated photon counting technique for fluorescence analysis. BIOMEDICAL OPTICS EXPRESS 2020; 11:2205-2212. [PMID: 32341877 PMCID: PMC7173894 DOI: 10.1364/boe.385870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/11/2020] [Accepted: 03/18/2020] [Indexed: 05/21/2023]
Abstract
An ultralow level light detection module, the time-correlated photon counter, is proposed and evaluated for fluorescence analysis. The time-correlated photon counter employs a silicon photomultiplier as a photon counting sensor in conjunction with a Poisson statistics algorithm and a double time windows technique, and therefore it can accurately count the photon number. The time-correlated photon counter is compatible with the time-correlated single photon counting technique and can record the arrival time of very faint light signals. This low-cost and compact instrument was used to analyze the intensity and lifetime of fluorescein isothiocyanate; a limit of detection of 16 pg/ml with a large linear dynamic range from 2.86 pg/ml to 0.5 µg/ml was obtained, and the lifetime of fluorescein isothiocyanate was measured to be 3.758 ns, which agrees well with the results of a sophisticated commercial fluorescence analysis instrument. The time-correlated photon counter may be useful in applications such as point-of-care testing.
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Affiliation(s)
- Lei Dai
- Key Laboratory of Beam Technology of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China
| | - Jian Liu
- Key Laboratory of Beam Technology of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China
| | - Kun Liang
- Key Laboratory of Beam Technology of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China
| | - Ru Yang
- Key Laboratory of Beam Technology of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China
| | - Dejun Han
- Key Laboratory of Beam Technology of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China
- Beijing Key Laboratory of Applied Optics, Beijing 100875, China
| | - Bo Lu
- Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, China
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26
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Levitt JA, Poland SP, Krstajic N, Pfisterer K, Erdogan A, Barber PR, Parsons M, Henderson RK, Ameer-Beg SM. Quantitative real-time imaging of intracellular FRET biosensor dynamics using rapid multi-beam confocal FLIM. Sci Rep 2020; 10:5146. [PMID: 32198437 PMCID: PMC7083966 DOI: 10.1038/s41598-020-61478-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/14/2020] [Indexed: 01/21/2023] Open
Abstract
Fluorescence lifetime imaging (FLIM) is a quantitative, intensity-independent microscopical method for measurement of diverse biochemical and physical properties in cell biology. It is a highly effective method for measurements of Förster resonance energy transfer (FRET), and for quantification of protein-protein interactions in cells. Time-domain FLIM-FRET measurements of these dynamic interactions are particularly challenging, since the technique requires excellent photon statistics to derive experimental parameters from the complex decay kinetics often observed from fluorophores in living cells. Here we present a new time-domain multi-confocal FLIM instrument with an array of 64 visible beamlets to achieve parallelised excitation and detection with average excitation powers of ~ 1–2 μW per beamlet. We exemplify this instrument with up to 0.5 frames per second time-lapse FLIM measurements of cAMP levels using an Epac-based fluorescent biosensor in live HeLa cells with nanometer spatial and picosecond temporal resolution. We demonstrate the use of time-dependent phasor plots to determine parameterisation for multi-exponential decay fitting to monitor the fractional contribution of the activated conformation of the biosensor. Our parallelised confocal approach avoids having to compromise on speed, noise, accuracy in lifetime measurements and provides powerful means to quantify biochemical dynamics in living cells.
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Affiliation(s)
- James A Levitt
- Microscopy Innovation Centre, Guy's Campus, Kings College, London, SE1 1UL, UK.,Richard Dimbleby Laboratories, School of Cancer and Pharmaceutical Sciences, Guy's Campus, Kings College London, London, SE1 1UL, UK
| | - Simon P Poland
- Richard Dimbleby Laboratories, School of Cancer and Pharmaceutical Sciences, Guy's Campus, Kings College London, London, SE1 1UL, UK
| | - Nikola Krstajic
- Institute for Microelectronics and Nanosystems, School of Engineering, College of Science and Engineering, University of Edinburgh, Edinburgh, EH9 3FB, UK
| | - Karin Pfisterer
- Randall Centre for Cell and Molecular Biophysics, Guy's Campus, Kings College, London, SE1 1UL, UK
| | - Ahmet Erdogan
- Institute for Microelectronics and Nanosystems, School of Engineering, College of Science and Engineering, University of Edinburgh, Edinburgh, EH9 3FB, UK
| | - Paul R Barber
- UCL Cancer Institute, Paul O'Gorman Building, University College London, London, WC1E 6DD, UK
| | - Maddy Parsons
- Randall Centre for Cell and Molecular Biophysics, Guy's Campus, Kings College, London, SE1 1UL, UK
| | - Robert K Henderson
- Institute for Microelectronics and Nanosystems, School of Engineering, College of Science and Engineering, University of Edinburgh, Edinburgh, EH9 3FB, UK
| | - Simon M Ameer-Beg
- Richard Dimbleby Laboratories, School of Cancer and Pharmaceutical Sciences, Guy's Campus, Kings College London, London, SE1 1UL, UK.
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27
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Zhou X, Li Z, Deng X, Yan B, Wang Z, Chen X, Huang S. High performance perovskite solar cells using Cu 9S 5 supraparticles incorporated hole transport layers. NANOTECHNOLOGY 2019; 30:445401. [PMID: 31349240 DOI: 10.1088/1361-6528/ab3604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We disclose novel photovoltaic device physics and present details of device mechanisms by investigating perovskite solar cells (PSCs) incorporating Cu9S5@SiO2 supraparticles (SUPs) into Spiro-OMeTAD based hole transport layers (HTLs). High quality colloidal Cu9S5 nanocrystals (NCs) were prepared using a hot-injection approach. Multiple Cu9S5 NCs were further embedded in silica to construct a Cu9S5@SiO2 SUP. Cu9S5@SiO2 SUPs were blended into Spiro-OMeTAD based HTLs with different weight ratios. Theoretical and experimental results show that the very strong light scattering or reflecting properties of Cu9S5@SiO2 SUPs blended in the PSC device in a proper proportion distribute to increase the light energy trapped within the device, leading to significant enhancement of light absorption in the active layer. Additionally, the incorporated Cu9S5@SiO2 SUPs can also promote the electrical conductivity and hole-transport capacity of the HTL. Significantly larger conductivity and higher hole injection efficiency were demonstrated in the HTM with the optimal weight ratios of Cu9S5@SiO2 SUPs. As a result, efficient Cu9S5 SUPs based PSC devices were obtained with average power conversion efficiency (PCE) of 18.21% at an optimal weight ratio of Cu9S5 SUPs. Compared with PSC solar cells without Cu9S5@SiO2 SUPs (of which the average PCE is 14.38%), a remarkable enhancement over 26% in average PCE was achieved. This study provides an innovative approach to efficiently promote the performance of PSC devices by employing optically stable, low-cost and green p-type semiconductor SUPs.
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Affiliation(s)
- Xin Zhou
- Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, School of Physics and Materials Science, East China Normal University, North Zhongshan Rd. 3663, Shanghai 200062, People's Republic of China
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28
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Lazzari-Dean JR, Gest AM, Miller EW. Optical estimation of absolute membrane potential using fluorescence lifetime imaging. eLife 2019; 8:44522. [PMID: 31545164 PMCID: PMC6814365 DOI: 10.7554/elife.44522] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 09/16/2019] [Indexed: 12/29/2022] Open
Abstract
All cells maintain ionic gradients across their plasma membranes, producing transmembrane potentials (Vmem). Mounting evidence suggests a relationship between resting Vmem and the physiology of non-excitable cells with implications in diverse areas, including cancer, cellular differentiation, and body patterning. A lack of non-invasive methods to record absolute Vmem limits our understanding of this fundamental signal. To address this need, we developed a fluorescence lifetime-based approach (VF-FLIM) to visualize and optically quantify Vmem with single-cell resolution in mammalian cell culture. Using VF-FLIM, we report Vmem distributions over thousands of cells, a 100-fold improvement relative to electrophysiological approaches. In human carcinoma cells, we visualize the voltage response to growth factor stimulation, stably recording a 10-15 mV hyperpolarization over minutes. Using pharmacological inhibitors, we identify the source of the hyperpolarization as the Ca2+-activated K+ channel KCa3.1. The ability to optically quantify absolute Vmem with cellular resolution will allow a re-examination of its signaling roles.
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Affiliation(s)
- Julia R Lazzari-Dean
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Anneliese Mm Gest
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Evan W Miller
- Department of Chemistry, University of California, Berkeley, Berkeley, United States.,Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, United States
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29
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Zhu JL, Xu L, Ren YY, Zhang Y, Liu X, Yin GQ, Sun B, Cao X, Chen Z, Zhao XL, Tan H, Chen J, Li X, Yang HB. Switchable organoplatinum metallacycles with high quantum yields and tunable fluorescence wavelengths. Nat Commun 2019; 10:4285. [PMID: 31537803 PMCID: PMC6753206 DOI: 10.1038/s41467-019-12204-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 08/27/2019] [Indexed: 01/14/2023] Open
Abstract
The preparation of fluorescent discrete supramolecular coordination complexes (SCCs) has attracted considerable attention within the fields of supramolecular chemistry, materials science, and biological sciences. However, many challenges remain. For instance, fluorescence quenching often occurs due to the heavy-atom effect arising from the Pt(II)-based building block in Pt-based SCCs. Moreover, relatively few methods exist for tuning of the emission wavelength of discrete SCCs. Thus, it is still challenging to construct discrete SCCs with high fluorescence quantum yields and tunable fluorescence wavelengths. Here we report nine organoplatinum fluorescent metallacycles that exhibit high fluorescence quantum yields and tunable fluorescence wavelengths through simple regulation of their photoinduced electron transfer (PET) and intramolecular charge transfer (ICT) properties. Moreover, 3D fluorescent films and fluorescent inks for inkjet printing were fabricated using these metallacycles. This work provides a strategy to solve the fluorescence quenching problem arising from the heavy-atom effect of Pt(II), and offers an alternative approach to tune the emission wavelengths of discrete SCCs in the same solvent. Fluorescent supramolecular coordination complexes are of interest for chemical sensing and optical devices. Here the authors synthesize nine organoplatinum metallacycles with high quantum yields, whose fluorescence wavelengths are tuned through manipulation of their photoinduced electron transfer and intramolecular charge transfer properties.
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Affiliation(s)
- Jun-Long Zhu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663N. Zhongshan Road, Shanghai, 200062, China
| | - Lin Xu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663N. Zhongshan Road, Shanghai, 200062, China.
| | - Yuan-Yuan Ren
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663N. Zhongshan Road, Shanghai, 200062, China
| | - Ying Zhang
- College of Chemistry, Beijing Normal University, Beijing, 100050, China
| | - Xi Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663N. Zhongshan Road, Shanghai, 200062, China
| | - Guang-Qiang Yin
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663N. Zhongshan Road, Shanghai, 200062, China.,Department of Chemistry, University of South Florida, Tampa, FL, 33620, USA
| | - Bin Sun
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663N. Zhongshan Road, Shanghai, 200062, China
| | - Xiaodan Cao
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200062, China
| | - Zhuang Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200062, China
| | - Xiao-Li Zhao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663N. Zhongshan Road, Shanghai, 200062, China
| | - Hongwei Tan
- College of Chemistry, Beijing Normal University, Beijing, 100050, China
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200062, China
| | - Xiaopeng Li
- Department of Chemistry, University of South Florida, Tampa, FL, 33620, USA
| | - Hai-Bo Yang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663N. Zhongshan Road, Shanghai, 200062, China.
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30
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Figueiras E, Silvestre OF, Ihalainen TO, Nieder JB. Phasor-assisted nanoscopy reveals differences in the spatial organization of major nuclear lamina proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118530. [PMID: 31415840 DOI: 10.1016/j.bbamcr.2019.118530] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/18/2019] [Accepted: 08/05/2019] [Indexed: 11/15/2022]
Abstract
Phasor-assisted Metal Induced Energy Transfer-Fluorescence Lifetime Imaging Microscopy (MIET-FLIM) nanoscopy is introduced as a powerful tool for functional cell biology research. Thin metal substrates can be used to obtain axial super-resolution via nanoscale distance-dependent MIET from fluorescent dyes towards a nearby metal layer, thereby creating fluorescence lifetime contrast between dyes located at different nanoscale distance from the metal. Such data can be used to achieve axially super-resolved microscopy images, a process known as MIET-FLIM nanoscopy. Suitability of the phasor approach in MIET-FLIM nanoscopy is first demonstrated using nanopatterned substrates, and furthermore applied to characterize the distance distribution of the epithelial basal membrane of a biological cell from the gold substrate. The phasor plot of an entire cell can be used to characterize the full Förster resonance energy transfer (FRET) trajectory as a large distance heterogeneity within the sensing range of about 100 nm from the metal surface is present due to the extended shape of cell with curvatures. In contrast, the different proteins of nuclear lamina show strong confinement close to the nuclear envelope in nanoscale. We find the lamin B layer resides in average at shorter distances from the gold surface compared to the lamin A/C layer located in more extended ranges. This and the observed heterogeneity of the protein layer thicknesses suggests that A- and B-type lamins form distinct networks in the nuclear lamina. Our results provide detailed insights for the study of the different roles of lamin proteins in chromatin tethering and nuclear mechanics.
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Affiliation(s)
- Edite Figueiras
- Department of Nanophotonics, Ultrafast Bio- and Nanophotonics Group, INL - International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Oscar F Silvestre
- Department of Nanophotonics, Ultrafast Bio- and Nanophotonics Group, INL - International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Teemu O Ihalainen
- Faculty of Medicine and Health Technology, BioMediTech, Tampere University, 33014 Tampere, Finland
| | - Jana B Nieder
- Department of Nanophotonics, Ultrafast Bio- and Nanophotonics Group, INL - International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal.
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31
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Hirmiz N, Tsikouras A, Osterlund EJ, Richards M, Andrews DW, Fang Q. Cross-talk reduction in a multiplexed synchroscan streak camera with simultaneous calibration. OPTICS EXPRESS 2019; 27:22602-22614. [PMID: 31510548 DOI: 10.1364/oe.27.022602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/14/2019] [Indexed: 06/10/2023]
Abstract
The streak camera is a picosecond resolution photodetector with parallel input capability; however, the degree of multiplexing is limited by crosstalk and temporal uncertainty in the sweeping field. We introduced a fixed time delay between adjacent fibers to reduce crosstalk in the synchroscan mode. The fixed delay and a tunable electronic delay between the input pulse and the synchroscan unit allows robust separation modes between the streaks, while spatial and temporal nonlinearities can be calibrated in. The efficacy of the design is demonstrated through a 100-fold multiplexed confocal fluorescence lifetime imaging microscope in live cells.
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32
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Li L, Zhang C, Wang P, Wang A, Zhou J, Chen G, Xu J, Yang Y, Zhao Y, Zhang S, Tian Y. Imaging the Redox States of Live Cells with the Time-Resolved Fluorescence of Genetically Encoded Biosensors. Anal Chem 2019; 91:3869-3876. [PMID: 30777423 DOI: 10.1021/acs.analchem.8b04292] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Redox environments in cells influence many important physiological and pathological processes. In this study, the time-resolved fluorescence of a recently reported thiol redox-sensitive sensor based on vertebrate fluorescent protein UnaG, roUnaG, was studied, along with the application of the time-resolved fluorescence of roUnaG to image the redox states of the mitochondria, cytoplasm, and nucleus in live cells. Time-resolved fluorescence images of roUnaG clearly demonstrated that potent anticancer compound KP372-1 induced extreme oxidative stress. A more stressful redox state observed in activated macrophages further demonstrated the validity of roUnaG with time-resolved fluorescence. For comparison, time-resolved fluorescence images of four other frequently used redox biosensors (roGFP1, HyPer, HyPerRed, and rxRFP) were also captured. The time-resolved fluorescence allows an intrinsically ratiometric measurement for biosensors with one excitation wavelength and provides new opportunities for bioimaging.
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Affiliation(s)
- Lei Li
- State Key Laboratory of Precision Spectroscopy , East China Normal University , 3663 North Zhongshan Road , Shanghai 200062 , China.,School of Science , Jiangnan University , Wuxi 214122 , China
| | | | - Peng Wang
- State Key Laboratory of Precision Spectroscopy , East China Normal University , 3663 North Zhongshan Road , Shanghai 200062 , China
| | | | - Jiasheng Zhou
- State Key Laboratory of Precision Spectroscopy , East China Normal University , 3663 North Zhongshan Road , Shanghai 200062 , China
| | - Guoqing Chen
- School of Science , Jiangnan University , Wuxi 214122 , China
| | - Jianhua Xu
- State Key Laboratory of Precision Spectroscopy , East China Normal University , 3663 North Zhongshan Road , Shanghai 200062 , China
| | - Yi Yang
- Optogenetics & Synthetic Biology Interdisciplinary Research Center, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences , Chinese Academy of Sciences , Shanghai 200031 , China
| | | | - Sanjun Zhang
- State Key Laboratory of Precision Spectroscopy , East China Normal University , 3663 North Zhongshan Road , Shanghai 200062 , China.,Collaborative Innovation Center of Extreme Optics , Shanxi University , Taiyuan , Shanxi 030006 , China.,NYU-ECNU Institute of Physics at NYU Shanghai , No. 3663, North Zhongshan Road , Shanghai 200062 , China
| | - Yang Tian
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering , East China Normal University , Dongchuan Road 500 , Shanghai 200241 , China
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33
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Zhong Y, Song B, Shen X, Guo D, He Y. Fluorescein sodium ligand-modified silicon nanoparticles produce ultrahigh fluorescence with robust pH- and photo-stability. Chem Commun (Camb) 2019; 55:365-368. [DOI: 10.1039/c8cc07340f] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Water-dispersed silicon nanoparticles (SiNPs) feature ultrahigh fluorescence (photoluminescent quantum yield (PLQY): ∼90%), robust pH- and photo-stability, and favourable biocompatibility.
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Affiliation(s)
- Yiling Zhong
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices
- Institute of Functional Nano & Soft Materials (FUNSOM), and Collaborative Innovation Centre of Suzhou Nano Science and Technology (NANO-CIC)
- Soochow University
- Suzhou
- China
| | - Bin Song
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices
- Institute of Functional Nano & Soft Materials (FUNSOM), and Collaborative Innovation Centre of Suzhou Nano Science and Technology (NANO-CIC)
- Soochow University
- Suzhou
- China
| | - Xiaobin Shen
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices
- Institute of Functional Nano & Soft Materials (FUNSOM), and Collaborative Innovation Centre of Suzhou Nano Science and Technology (NANO-CIC)
- Soochow University
- Suzhou
- China
| | - Daoxia Guo
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices
- Institute of Functional Nano & Soft Materials (FUNSOM), and Collaborative Innovation Centre of Suzhou Nano Science and Technology (NANO-CIC)
- Soochow University
- Suzhou
- China
| | - Yao He
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices
- Institute of Functional Nano & Soft Materials (FUNSOM), and Collaborative Innovation Centre of Suzhou Nano Science and Technology (NANO-CIC)
- Soochow University
- Suzhou
- China
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34
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pH Resistant Ratiometric Measurement of Nicotinamide Adenine Dinucleotide Levels by Time-resolved Fluorescence Spectroscopy. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2019. [DOI: 10.1016/s1872-2040(18)61138-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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35
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Zheng K, Jensen TP, Rusakov DA. Monitoring intracellular nanomolar calcium using fluorescence lifetime imaging. Nat Protoc 2018; 13:581-597. [PMID: 29470463 DOI: 10.1038/nprot.2017.154] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nanomolar-range fluctuations of intracellular [Ca2+] are critical for brain cell function but remain difficult to measure. We have advanced a microscopy technique to monitor intracellular [Ca2+] in individual cells in acute brain slices (also applicable in vivo) using fluorescence lifetime imaging (FLIM) of the Ca2+-sensitive fluorescent indicator Oregon Green BAPTA1 (OGB-1). The OGB-1 fluorescence lifetime is sensitive to [Ca2+] within the 10-500 nM range but not to other factors such as viscosity, temperature, or pH. This protocol describes the requirements, setup, and calibration of the FLIM system required for OGB-1 imaging. We provide a step-by-step procedure for whole-cell OGB-1 loading and two-photon FLIM. We also describe how to analyze the obtained FLIM data using total photon count and gated-intensity record, a ratiometric photon-counting approach that provides a highly improved signal-to-noise ratio and greater sensitivity of absolute [Ca2+] readout. We demonstrate our technique in nerve cells in situ, and it is adaptable to other cell types and fluorescent indicators. This protocol requires a basic understanding of FLIM and experience in single-cell electrophysiology and cell imaging. Setting up the FLIM system takes ∼2 d, and OGB-1 loading, imaging, and data analysis take 2 d.
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Affiliation(s)
- Kaiyu Zheng
- UCL Institute of Neurology, University College London, London, UK
| | - Thomas P Jensen
- UCL Institute of Neurology, University College London, London, UK
| | - Dmitri A Rusakov
- UCL Institute of Neurology, University College London, London, UK
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36
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Shen N, Riedl JA, Carvajal Berrio DA, Davis Z, Monaghan MG, Layland SL, Hinderer S, Schenke-Layland K. A flow bioreactor system compatible with real-time two-photon fluorescence lifetime imaging microscopy. ACTA ACUST UNITED AC 2018; 13:024101. [PMID: 29148433 DOI: 10.1088/1748-605x/aa9b3c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bioreactors are essential cell and tissue culture tools that allow the introduction of biophysical signals into in vitro cultures. One major limitation is the need to interrupt experiments and sacrifice samples at certain time points for analyses. To address this issue, we designed a bioreactor that combines high-resolution contact-free imaging and continuous flow in a closed system that is compatible with various types of microscopes. The high throughput fluid flow bioreactor was combined with two-photon fluorescence lifetime imaging microscopy (2P-FLIM) and validated. The hydrodynamics of the bioreactor chamber were characterized using COMSOL. The simulation of shear stress indicated that the bioreactor system provides homogeneous and reproducible flow conditions. The designed bioreactor was used to investigate the effects of low shear stress on human umbilical vein endothelial cells (HUVECs). In a scratch assay, we observed decreased migration of HUVECs under shear stress conditions. Furthermore, metabolic activity shifts from glycolysis to oxidative phosphorylation-dependent mechanisms in HUVECs cultured under low shear stress conditions were detected using 2P-FLIM. Future applications for this bioreactor range from observing cell fate development in real-time to monitoring the environmental effects on cells or metabolic changes due to drug applications.
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Affiliation(s)
- Nian Shen
- Department of Women's Health, Research Institute of Women's Health, University Hospital of the Eberhard Karls University, Tübingen, Germany. Department of Cell and Tissue Engineering, Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Stuttgart, Germany
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37
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Chang M, Li L, Hu H, Hu Q, Wang A, Cao X, Yu X, Zhang S, Zhao Y, Chen J, Yang Y, Xu J. Using Fractional Intensities of Time-resolved Fluorescence to Sensitively Quantify NADH/NAD + with Genetically Encoded Fluorescent Biosensors. Sci Rep 2017. [PMID: 28646144 PMCID: PMC5482812 DOI: 10.1038/s41598-017-04051-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In this paper, we propose a novel and sensitive ratiometric analysis method that uses the fractional intensities of time-resolved fluorescence of genetically encoded fluorescent NADH/NAD+ biosensors, Peredox, SoNar, and Frex. When the conformations of the biosensors change upon NADH/NAD+ binding, the fractional intensities (αiτi) have opposite changing trends. Their ratios could be exploited to quantify NADH/NAD+ levels with a larger dynamic range and higher resolution versus commonly used fluorescence intensity and lifetime methods. Moreover, only one excitation and one emission wavelength are required for this ratiometric measurement. This eliminates problems of traditional excitation-ratiometric and emission-ratiometric methods. This method could be used to simplify the design and achieve highly sensitive analyte quantification of genetically encoded fluorescent biosensors. Wide potential applications could be developed for imaging live cell metabolism based on this new method.
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Affiliation(s)
- Mengfang Chang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062, China
| | - Lei Li
- State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062, China
| | - Hanyang Hu
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, 130 Mei Long Road, Shanghai, 200237, China.,Optogenetics & Synthetic Biology Interdisciplinary Research Center, CAS Center for Excellence in Brain Science, 130 Mei Long Road, Shanghai, 200237, China.,Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai, 200237, China
| | - Qingxun Hu
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, 130 Mei Long Road, Shanghai, 200237, China.,Optogenetics & Synthetic Biology Interdisciplinary Research Center, CAS Center for Excellence in Brain Science, 130 Mei Long Road, Shanghai, 200237, China.,Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai, 200237, China
| | - Aoxue Wang
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, 130 Mei Long Road, Shanghai, 200237, China.,Optogenetics & Synthetic Biology Interdisciplinary Research Center, CAS Center for Excellence in Brain Science, 130 Mei Long Road, Shanghai, 200237, China.,Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai, 200237, China
| | - Xiaodan Cao
- State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062, China
| | - Xiantong Yu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062, China
| | - Sanjun Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062, China.
| | - Yuzheng Zhao
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, 130 Mei Long Road, Shanghai, 200237, China. .,Optogenetics & Synthetic Biology Interdisciplinary Research Center, CAS Center for Excellence in Brain Science, 130 Mei Long Road, Shanghai, 200237, China. .,Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai, 200237, China.
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062, China
| | - Yi Yang
- Synthetic Biology and Biotechnology Laboratory, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, 130 Mei Long Road, Shanghai, 200237, China.,Optogenetics & Synthetic Biology Interdisciplinary Research Center, CAS Center for Excellence in Brain Science, 130 Mei Long Road, Shanghai, 200237, China.,Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai, 200237, China
| | - Jianhua Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062, China
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38
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Li L, Yi H, Jia M, Chang M, Zhou Z, Zhang S, Pan H, Chen Y, Chen J, Xu J. Time-Resolved Fluorescence of Water-Soluble Pyridinium Salt: Sensitive Detection of the Conformational Changes of Bovine Serum Albumin. APPLIED SPECTROSCOPY 2016; 70:1733-1738. [PMID: 27324423 DOI: 10.1177/0003702816644609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/15/2016] [Indexed: 06/06/2023]
Abstract
In this paper, we report a pyridinium salt "turn-on" fluorescent probe, 4-[2-(4-Dimethylamino-phenyl)-vinyl]-1-methylpyridinium iodide (p-DASPMI), and applied its time-resolved fluorescence (TRF) to monitor the protein conformational changes. Both the fluorescence lifetime and quantum yield (QY) of p-DASPMI were increased about two orders of magnitude after binding to the protein bovine serum albumin (BSA). The free p-DASPMI in solution presents an ultrashort fluorescence lifetime (12.4 ps), thus it does not interfere the detection of bound p-DASPMI which has nanosecond fluorescence lifetime. Decay-associated spectra (DAS) show that p-DASPMI molecules bind to subdomains IIA and IIIA of BSA. The TRF decay profiles of p-DASPMI can be described by multi-exponential decay function ([Formula: see text]), and the obtained parameters, such as lifetimes ([Formula: see text]), fractional amplitudes ([Formula: see text]), and fractional intensities ([Formula: see text]), may be used to deduce the conformational changes of BSA. The pH and Cu2+ induced conformational changes of BSA were investigated through the TRF of p-DASPMI. The results show that the p-DASPMI is a candidate fluorescent probe in studying the conformational changes of proteins through TRF spectroscopy and microscopy in the visible range.
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Affiliation(s)
- Lei Li
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Hua Yi
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Menghui Jia
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Mengfang Chang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Zhongneng Zhou
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Sanjun Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China Collaborative Innovation Centre of Extreme Optics, Shanxi University, Taiyuan, China
| | - Haifeng Pan
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Yan Chen
- Tongji Hospital Affiliated to Tongji University, Shanghai, China
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Jianhua Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China Collaborative Innovation Centre of Extreme Optics, Shanxi University, Taiyuan, China
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Li L, Chang M, Yi H, Jia M, Cao X, Zhou Z, Zhang S, Pan H, Shih CW, Jimenez R, Xu J. Using Pyridinium Styryl Dyes as the Standards of Time-Resolved Instrument Response. APPLIED SPECTROSCOPY 2016; 70:1195-1201. [PMID: 27231333 DOI: 10.1177/0003702816652363] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/13/2015] [Indexed: 06/05/2023]
Abstract
In this paper, two pyridinium styryl dyes, [2-(4-dimethylamino-phenyl)-vinyl]-1-methylpyridinium iodide (DASPMI), were synthesized and characterized by steady state fluorescence spectroscopy as well as picosecond and femtosecond time-resolved fluorescence spectroscopies. Both dyes exhibit large Stokes shifts and fluorescence decays equivalent to the instrument response function (IRF) standards employed in time-correlated single-photon counting. Due to their styryl and pyridinium moieties, DASPMIs have higher peak fluorescence intensity and shorter excited-state lifetimes than iodide ion-quenched fluorophores. The fluorescence lifetimes of o-DASPMI and p-DASPMI were measured to be 6.6 ps and 12.4 ps, respectively. The fluorescence transients of these DASPMIs were used as the IRFs for iterative reconvolution fitting of the time-resolved fluorescence decay profiles of Rhodamine B (RhB), sulforhodamine B (SRB), and the SRB-SRB2m RNA aptamer complex. The quality of the fits employing the DASPMI-derived IRFs are consistently equivalent to those employing IRFs obtained from light scattering. These results indicate that DASPMI-derived IRFs may be suited for a broad range of applications in time-resolved spectroscopy and fluorescence lifetime imaging microscopy (FLIM), especially in the visible emission range.
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Affiliation(s)
- Lei Li
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Mengfang Chang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Hua Yi
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Menghui Jia
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Xiaodan Cao
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Zhongneng Zhou
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Sanjun Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Haifeng Pan
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
| | - Chun-Wei Shih
- JILA, National Institute of Standards and Technology (NIST), University of Colorado, Boulder, Colorado, USA
| | - Ralph Jimenez
- JILA, National Institute of Standards and Technology (NIST), University of Colorado, Boulder, Colorado, USA
| | - Jianhua Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
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The interactions between a small molecule and G-quadruplexes are visualized by fluorescence lifetime imaging microscopy. Nat Commun 2015; 6:8178. [PMID: 26350962 PMCID: PMC4579598 DOI: 10.1038/ncomms9178] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/25/2015] [Indexed: 12/12/2022] Open
Abstract
Guanine-rich oligonucleotides can fold into quadruple-stranded helical structures known as G-quadruplexes. Mounting experimental evidence has gathered suggesting that these non-canonical nucleic acid structures form in vivo and play essential biological roles. However, to date, there are no small-molecule optical probes to image G-quadruplexes in live cells. Herein, we report the design and development of a small fluorescent molecule, which can be used as an optical probe for G-quadruplexes. We demonstrate that the fluorescence lifetime of this new probe changes considerably upon interaction with different nucleic acid topologies. Specifically, longer fluorescence lifetimes are observed in vitro for G-quadruplexes than for double- and single-stranded nucleic acids. Cellular studies confirm that this molecule is cell permeable, has low cytotoxicity and localizes primarily in the cell nucleus. Furthermore, using fluorescence lifetime imaging microscopy, live-cell imaging suggests that the probe can be used to study the interaction of small molecules with G-quadruplexes in vivo. Guanine-rich oligonucleotides can fold into secondary structures known as G-quadruplexes that are proposed to have various biological roles. Here, Shivalingam et al. develop a cell-permeable, low-toxicity probe that can be used to probe interactions between G-quadruplexes and small molecules in vivo.
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