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Bénard M, Chamot C, Schapman D, Debonne A, Lebon A, Dubois F, Levallet G, Komuro H, Galas L. Combining sophisticated fast FLIM, confocal microscopy, and STED nanoscopy for live-cell imaging of tunneling nanotubes. Life Sci Alliance 2024; 7:e202302398. [PMID: 38649185 PMCID: PMC11035862 DOI: 10.26508/lsa.202302398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 04/25/2024] Open
Abstract
Cell-to-cell communication via tunneling nanotubes (TNTs) is a challenging topic with a growing interest. In this work, we proposed several innovative tools that use red/near-infrared dye labeling and employ lifetime-based imaging strategies to investigate the dynamics of TNTs in a living mesothelial H28 cell line that exhibits spontaneously TNT1 and TNT2 subtypes. Thanks to a fluorescence lifetime imaging microscopy module being integrated into confocal microscopy and stimulated emission depletion nanoscopy, we applied lifetime imaging, lifetime dye unmixing, and lifetime denoising techniques to perform multiplexing experiments and time-lapses of tens of minutes, revealing therefore structural and functional characteristics of living TNTs that were preserved from light exposure. In these conditions, vesicle-like structures, and tubular- and round-shaped mitochondria were identified within living TNT1. In addition, mitochondrial dynamic studies revealed linear and stepwise mitochondrial migrations, bidirectional movements, transient backtracking, and fission events in TNT1. Transfer of Nile Red-positive puncta via both TNT1 and TNT2 was also detected between living H28 cells.
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Affiliation(s)
- Magalie Bénard
- University Rouen Normandie, INSERM, CNRS, Normandie Université, HeRacLeS US51, UAR2026, PRIMACEN, Rouen, France
| | - Christophe Chamot
- University Rouen Normandie, INSERM, CNRS, Normandie Université, HeRacLeS US51, UAR2026, PRIMACEN, Rouen, France
| | - Damien Schapman
- University Rouen Normandie, INSERM, CNRS, Normandie Université, HeRacLeS US51, UAR2026, PRIMACEN, Rouen, France
| | - Aurélien Debonne
- University Rouen Normandie, INSERM, CNRS, Normandie Université, HeRacLeS US51, UAR2026, PRIMACEN, Rouen, France
- University Rouen Normandie, INSERM, Normandie Université, UMR1245, Rouen, France
| | - Alexis Lebon
- University Rouen Normandie, INSERM, CNRS, Normandie Université, HeRacLeS US51, UAR2026, PRIMACEN, Rouen, France
| | - Fatéméh Dubois
- Université de Caen Normandie, CNRS, Normandie Université, ISTCT UMR6030, Caen, France
- Service d'Anatomie et Cytologie Pathologiques, CHU de Caen, Caen, France
| | - Guénaëlle Levallet
- Université de Caen Normandie, CNRS, Normandie Université, ISTCT UMR6030, Caen, France
- Service d'Anatomie et Cytologie Pathologiques, CHU de Caen, Caen, France
| | - Hitoshi Komuro
- University Rouen Normandie, INSERM, CNRS, Normandie Université, HeRacLeS US51, UAR2026, PRIMACEN, Rouen, France
| | - Ludovic Galas
- University Rouen Normandie, INSERM, CNRS, Normandie Université, HeRacLeS US51, UAR2026, PRIMACEN, Rouen, France
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2
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Booth E, Garre M, Wu D, Daly HC, O’Shea DF. A NIR-Fluorochrome for Live Cell Dual Emission and Lifetime Tracking from the First Plasma Membrane Interaction to Subcellular and Extracellular Locales. Molecules 2024; 29:2474. [PMID: 38893352 PMCID: PMC11174088 DOI: 10.3390/molecules29112474] [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: 04/19/2024] [Revised: 05/15/2024] [Accepted: 05/22/2024] [Indexed: 06/21/2024] Open
Abstract
Molecular probes with the ability to differentiate between subcellular variations in acidity levels remain important for the investigation of dynamic cellular processes and functions. In this context, a series of cyclic peptide and PEG bio-conjugated dual near-infrared emissive BF2-azadipyrromethene fluorophores with maxima emissions at 720 nm (at pH > 6) and 790 nm (at pH < 5) have been developed and their aqueous solution photophysical properties determined. Their inter-converting emissions and fluorescence lifetime characteristics were exploited to track their spatial and temporal progression from first contact with the plasma membrane to subcellular locales to their release within extracellular vesicles. A pH-dependent reversible phenolate/phenol interconversion on the fluorophore controlled the dynamic changes in dual emission responses and corresponding lifetime changes. Live-cell confocal microscopy experiments in the metastatic breast cancer cell line MDA-MB-231 confirmed the usability of the dual emissive properties for imaging over prolonged periods. All three derivatives performed as probes capable of real-time continuous imaging of fundamental cellular processes such as plasma membrane interaction, tracking endocytosis, lysosomal/large acidic vesicle accumulation, and efflux within extracellular vesicles without perturbing cellular function. Furthermore, fluorescence lifetime imaging microscopy provided valuable insights regarding fluorophore progression through intracellular microenvironments over time. Overall, the unique photophysical properties of these fluorophores show excellent potential for their use as information-rich probes.
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Affiliation(s)
| | | | | | | | - Donal F. O’Shea
- Department of Chemistry, Royal College of Surgeons in Ireland (RCSI), D02 PN40 Dublin, Ireland
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3
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Spadin FS, Gergely LP, Kämpfer T, Frenz M, Vermathen M. Fluorescence lifetime imaging and phasor analysis of intracellular porphyrinic photosensitizers applied with different polymeric formulations. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 254:112904. [PMID: 38579534 DOI: 10.1016/j.jphotobiol.2024.112904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 03/06/2024] [Accepted: 04/01/2024] [Indexed: 04/07/2024]
Abstract
The fluorescence lifetime of a porphyrinic photosensitizer (PS) is an important parameter to assess the aggregation state of the PS even in complex biological environments. Aggregation-induced quenching of the PS can significantly reduce the yield of singlet oxygen generation and thus its efficiency as a medical drug in photodynamic therapy (PDT) of diseased tissues. Hydrophobicity and the tendency to form aggregates pose challenges on the development of efficient PSs and often require carrier systems. A systematic study was performed to probe the impact of PS structure and encapsulation into polymeric carriers on the fluorescence lifetime in solution and in the intracellular environment. Five different porphyrinic PSs including chlorin e6 (Ce6) derivatives and tetrakis(m-hydroxyphenyl)-porphyrin and -chlorin were studied in free form and combined with polyvinylpyrrolidone (PVP) or micelles composed of triblock-copolymers or Cremophor. Following incubation of HeLa cells with these systems, fluorescence lifetime imaging combined with phasor analysis and image segmentation was applied to study the lifetime distribution in the intracellular surrounding. The data suggest that for free PSs, the structure-dependent cell uptake pathways determine their state and emission lifetimes. PS localization in the plasma membrane yielded mostly monomers with long fluorescence lifetimes whereas the endocytic pathway with subsequent lysosomal deposition adds a short-lived component for hydrophilic anionic PSs. Prolonged incubation times led to increasing contributions from short-lived components that derive from aggregates mainly localized in the cytoplasm. Encapsulation of PSs into polymeric carriers led to monomerization and mostly fluorescence emission decays with long fluorescence lifetimes in solution. However, the efficiency depended on the binding strength that was most pronounced for PVP. In the cellular environment, PVP was able to maintain monomeric long-lived species over prolonged incubation times. This was most pronounced for Ce6 derivatives with a logP value around 4.5. Micellar encapsulation led to faster release of the PSs resulting in multiple components with long and short fluorescence lifetimes. The hydrophilic hardly aggregating PS exhibited a mostly stable invariant lifetime distribution over time with both carriers. The presented data are expected to contribute to optimized PDT treatment protocols and improved PS-carrier design for preventing intracellular fluorescence quenching. In conclusion, amphiphilic and concurrent hydrophobic PSs with high membrane affinity as well as strong binding to the carrier have best prospects to maintain their photophysical properties in vivo and serve thus as efficient photodynamic diagnosis and PDT drugs.
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Affiliation(s)
- Florentin S Spadin
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Lea P Gergely
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, Freiestrasse 3, 3012 Bern, Switzerland
| | - Tobias Kämpfer
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, Freiestrasse 3, 3012 Bern, Switzerland
| | - Martin Frenz
- Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.
| | - Martina Vermathen
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, Freiestrasse 3, 3012 Bern, Switzerland.
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4
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Obeso JL, López-Cervantes VB, Flores CV, Martínez A, Amador-Sánchez YA, Portillo-Velez NS, Lara-García HA, Leyva C, Solis-Ibarra D, Peralta RA. CYCU-3: an Al(III)-based MOF for SO 2 capture and detection. Dalton Trans 2024; 53:4790-4796. [PMID: 38372055 DOI: 10.1039/d3dt04073a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
The Al(III)-based MOF CYCU-3 exhibits a relevant SO2 adsorption performance with a total uptake of 11.03 mmol g-1 at 1 bar and 298 K. CYCU-3 displays high chemical stability towards dry and wet SO2 exposure. DRIFTS experiments and computational calculations demonstrated that hydrogen bonding between SO2 molecules and bridging Al(III)-OH groups are the preferential adsorption sites. In addition, photoluminescence experiments demonstrated the relevance of CYCU-3 for application in SO2 detection with good selectivity for SO2 over CO2 and H2O. The change in fluorescence performance demonstrates a clear turn-on effect after SO2 interaction. Finally, the suppression of ligand-metal energy transfer along with the enhancement of ligand-centered π* → π electronic transition was proposed as a plausible fluorescence mechanism.
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Affiliation(s)
- Juan L Obeso
- Instituto Politécnico Nacional, CICATA U. Legaria, Laboratorio Nacional de Ciencia, Tecnología y Gestión Integrada del Agua (LNAgua), Legaria 694, Irrigación, 11500, Miguel Hidalgo, CDMX, Mexico
- Laboratorio de Fisicoquímica y Reactividad de Superficies (LaFReS), Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, CU, Coyoacán, 04510, Ciudad de México, Mexico.
| | - Valeria B López-Cervantes
- Instituto Politécnico Nacional, CICATA U. Legaria, Laboratorio Nacional de Ciencia, Tecnología y Gestión Integrada del Agua (LNAgua), Legaria 694, Irrigación, 11500, Miguel Hidalgo, CDMX, Mexico
| | - Catalina V Flores
- Instituto Politécnico Nacional, CICATA U. Legaria, Laboratorio Nacional de Ciencia, Tecnología y Gestión Integrada del Agua (LNAgua), Legaria 694, Irrigación, 11500, Miguel Hidalgo, CDMX, Mexico
- Laboratorio de Fisicoquímica y Reactividad de Superficies (LaFReS), Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, CU, Coyoacán, 04510, Ciudad de México, Mexico.
| | - Ana Martínez
- Departamento de Materiales de baja Dimensionalidad. Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México. Circuito Interior SN, Ciudad Universitaria, CP 04510, Coyoacán, CDMX, Mexico
| | - Yoarhy A Amador-Sánchez
- Laboratorio de Fisicoquímica y Reactividad de Superficies (LaFReS), Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, CU, Coyoacán, 04510, Ciudad de México, Mexico.
| | - N S Portillo-Velez
- Departamento de Química, División de Ciencias Básicas e Ingeniería. Universidad Autónoma Metropolitana (UAM-I), 09340, Mexico.
| | - Hugo A Lara-García
- Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, Mexico City 0100, Mexico
| | - Carolina Leyva
- Instituto Politécnico Nacional, CICATA U. Legaria, Laboratorio Nacional de Ciencia, Tecnología y Gestión Integrada del Agua (LNAgua), Legaria 694, Irrigación, 11500, Miguel Hidalgo, CDMX, Mexico
| | - Diego Solis-Ibarra
- Laboratorio de Fisicoquímica y Reactividad de Superficies (LaFReS), Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, CU, Coyoacán, 04510, Ciudad de México, Mexico.
| | - Ricardo A Peralta
- Departamento de Química, División de Ciencias Básicas e Ingeniería. Universidad Autónoma Metropolitana (UAM-I), 09340, Mexico.
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5
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Houston JP, Valentino S, Bitton A. Fluorescence Lifetime Measurements and Analyses: Protocols Using Flow Cytometry and High-Throughput Microscopy. Methods Mol Biol 2024; 2779:323-351. [PMID: 38526793 DOI: 10.1007/978-1-0716-3738-8_15] [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] [Indexed: 03/27/2024]
Abstract
This chapter focuses on applications and protocols that involve the measurement of the fluorescence lifetime as an informative cytometric parameter. The timing of fluorescence decay has been well-studied for cell counting, sorting, and imaging. Therefore, provided herein is an overview of the techniques used, how they enhance cytometry protocols, and the modern techniques used for lifetime analysis. The background and theory behind fluorescence decay kinetic measurements in cells is first discussed followed by the history of the development of time-resolved flow cytometry. These sections are followed by a review of applications that benefit from the quantitative nature of fluorescence lifetimes as a photophysical trait. Lastly, perspectives on the modern ways in which the fluorescence lifetime is scanned at high throughputs which include high-speed microscopy and machine learning are provided.
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Affiliation(s)
- Jessica P Houston
- Department of Chemical & Materials Engineering, New Mexico State University, Las Cruces, NM, USA.
| | - Samantha Valentino
- Department of Chemical & Materials Engineering, New Mexico State University, Las Cruces, NM, USA
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6
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Zhang Z, Liu X, He M, Huang Y, Xu L, Han Y, Zhu D, Hao X, Kuang C, Liu X. High-throughput multiplexed fluorescence lifetime microscopy. OPTICS LETTERS 2023; 48:5547-5550. [PMID: 37910699 DOI: 10.1364/ol.503136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023]
Abstract
Fluorescence lifetime microscopy has been widely used in quantifying cellular interaction or histopathological identification of different stained tissues. A novel, to the best of our knowledge, approach for high-throughput multiplexed fluorescence lifetime imaging is presented. To establish a high-throughput fluorescence lifetime acquisition system, a uniformed illumination optical focus array was generated by a novel computer-generated hologram algorithm based on matrix triple product. This, in conjunction with an array detector and multichannel time-correlated single-photon counting, enables the full use of the acquisition ability of each detector. By utilizing interval segmentation of photon time detection, a high-throughput multiplexed fluorescence lifetime imaging is achieved. Experimental results demonstrate that this method achieves a fivefold increase in the collection throughput of fluorescence lifetime and is capable of simultaneous dual-target fluorescence lifetime measurement.
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7
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Balasubramanian H, Hobson CM, Chew TL, Aaron JS. Imagining the future of optical microscopy: everything, everywhere, all at once. Commun Biol 2023; 6:1096. [PMID: 37898673 PMCID: PMC10613274 DOI: 10.1038/s42003-023-05468-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/16/2023] [Indexed: 10/30/2023] Open
Abstract
The optical microscope has revolutionized biology since at least the 17th Century. Since then, it has progressed from a largely observational tool to a powerful bioanalytical platform. However, realizing its full potential to study live specimens is hindered by a daunting array of technical challenges. Here, we delve into the current state of live imaging to explore the barriers that must be overcome and the possibilities that lie ahead. We venture to envision a future where we can visualize and study everything, everywhere, all at once - from the intricate inner workings of a single cell to the dynamic interplay across entire organisms, and a world where scientists could access the necessary microscopy technologies anywhere.
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Affiliation(s)
| | - Chad M Hobson
- Advanced Imaging Center; Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Teng-Leong Chew
- Advanced Imaging Center; Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Jesse S Aaron
- Advanced Imaging Center; Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, 20147, USA.
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8
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Motz R, Sun AC, Lehnherr D, Ruccolo S. High-Throughput Determination of Stern-Volmer Quenching Constants for Common Photocatalysts and Quenchers. ACS ORGANIC & INORGANIC AU 2023; 3:266-273. [PMID: 37810410 PMCID: PMC10557125 DOI: 10.1021/acsorginorgau.3c00019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 10/10/2023]
Abstract
Mechanistic information on reactions proceeding via photoredox catalysis has enabled rational optimizations of existing reactions and revealed new synthetic pathways. One essential step in any photoredox reaction is catalyst quenching via photoinduced electron transfer or energy transfer with either a substrate, additive, or cocatalyst. Identification of the correct quencher using Stern-Volmer studies is a necessary step for mechanistic understanding; however, such studies are often cumbersome, low throughput and require specialized luminescence instruments. This report describes a high-throughput method to rapidly acquire a series of Stern-Volmer constants, employing readily available fluorescence plate readers and 96-well plates. By leveraging multichannel pipettors or liquid dispensing robots in combination with fast plate readers, the sampling frequency for quenching studies can be improved by several orders of magnitude. This new high-throughput method enabled the rapid collection of 220 quenching constants for a library of 20 common photocatalysts with 11 common quenchers. The extensive Stern-Volmer constant table generated greatly facilitates the systematic comparison between quenchers and can provide guidance to the synthetic community interested in designing and understanding catalytic photoredox reactions.
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Affiliation(s)
- Rachel
N. Motz
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Alexandra C. Sun
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Dan Lehnherr
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Serge Ruccolo
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
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9
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Investigating Plant Protein-Protein Interactions Using FRET-FLIM with a Focus on the Actin Cytoskeleton. Methods Mol Biol 2023; 2604:353-366. [PMID: 36773249 DOI: 10.1007/978-1-0716-2867-6_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The study of protein-protein interactions is fundamental to understanding how actin-dependent processes are controlled through the regulation of actin-binding proteins by their interactors. FRET-FLIM (Förster resonance energy transfer-fluorescence lifetime imaging microscopy) is a sensitive bioimaging method to detect protein-protein interactions in living cells through measurement of FRET, facilitated by the interactions of fluorophore-tagged fusion protein. As a sensitive and noninvasive method for the spatiotemporal visualization of dynamic protein-protein interactions, FRET-FLIM holds several advantages over other methods of protein interaction assays. FRET-FLIM has been widely employed to characterize many plant protein interactions, including interactions between actin-regulatory proteins and their binding partners. As we increasingly understand the plant actin cytoskeleton to coordinate a diverse number of complex functions, the study of actin-regulatory proteins and their interactors becomes increasingly technically challenging. Sophisticated and sensitive in vivo methods such as FRET-FLIM are likely to be crucial to the study of protein-protein interactions as more complex and challenging hypotheses are addressed.
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10
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Peng X, Huang J, Li M, Chen Z, Yan W, Qu J. Lipid Membrane Alterations in Tumor Spheroids Revealed by Fluorescence Lifetime Microscopy Imaging. Anal Chem 2023; 95:575-580. [PMID: 36576346 DOI: 10.1021/acs.analchem.2c05126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Three-dimensional (3D) cultured tumor spheroid models, as one type of in vitro model, have been proven to have more physiological similarities to in vivo animal models than cells in 2D cultures. Tumor spheroids have been widely used in preclinical experiments of anticancer drug treatments, providing reliable data in pathogenetic research. Currently, different 3D cell culture conditions, even in the same cell line, generate heterogeneous spheroids in morphology and size, resulting in different growth rates or drug-killing responses. Therefore, the measurement and evaluation of the properties of tumor spheroids have become highly demanding tasks with huge challenges. For functional characterization of tumor spheroids, the microenvironment sensitivity and quantitative properties of the fluorescence lifetime microscopy imaging (FLIM) technique have great advantages for improving the reliability of cell physiological testing. In this paper, we have proposed a FLIM-based approach to observe the lipid components labeled with Nile red of cells in both 3D and 2D cultures. The imaging data and analysis provided basic information on the sizes, morphologies, and cell membrane fluorescence lifetime values of the tumor spheroids. FLIM data showed that the microenvironment of the cell membrane in the 3D model was largely altered compared to that in the 2D culture. Next, a series of parameters that may influence the lipid components of tumor cells and tumor spheroids were tested by FLIM, including pH, viscosity, and polarity. The results showed that pH and viscosity contributed little to the change in fluorescence lifetime values, while the change in cell membrane polarity was the main cause of the alterations in fluorescence lifetime data, suggesting that cell membrane polarity should be considered a marker in distinguishing tumor spheroids from cellular physiological status. In conclusion, this FLIM-based testing process has been proven to be a quantitative method for measuring the differences between the cells of the 3D model from the 2D cultured cells with satisfactory sensitivity and accuracy, providing a high potential standard assay in the quality evaluation and control of tumor spheroids for future anticancer drug development.
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Affiliation(s)
- Xiao Peng
- College of Physics and Optoelectronic Engineering, Shenzhen Key Laboratory of Photonics and Biophotonics, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen518060, P. R. China
| | - Jingwen Huang
- College of Physics and Optoelectronic Engineering, Shenzhen Key Laboratory of Photonics and Biophotonics, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen518060, P. R. China
| | - Mingyue Li
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Sipailou #2, Nanjing, Jiangsu210096, P. R. China
| | - Zaozao Chen
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Sipailou #2, Nanjing, Jiangsu210096, P. R. China
| | - Wei Yan
- College of Physics and Optoelectronic Engineering, Shenzhen Key Laboratory of Photonics and Biophotonics, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen518060, P. R. China
| | - Junle Qu
- College of Physics and Optoelectronic Engineering, Shenzhen Key Laboratory of Photonics and Biophotonics, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen518060, P. R. China
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11
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Pal R, Kumar ATN. Comparison of fluorescence lifetime and multispectral imaging for quantitative multiplexing in biological tissue. BIOMEDICAL OPTICS EXPRESS 2022; 13:3854-3868. [PMID: 35991924 PMCID: PMC9352286 DOI: 10.1364/boe.459935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/03/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Fluorescence lifetime (FLT) multiplexing and multispectral imaging (MSI) are both frequently employed for in vitro and ex vivo biological studies. In vivo applications of MSI for deep seated fluorophores require consideration of diffusive light propagation in biological tissue. We have previously shown that a well-known redshift of fluorescence spectra in diffusive medium induces a fluorophore cross-talk, which cannot be accounted for even with known optical properties of the medium. In contrast, FLT measurements remain largely unaffected by light propagation in tissue, enabling zero cross-talk and accurate relative quantification. While a fully quantitative estimation of fluorophore concentrations requires depth resolved tomographic imaging, this is often not possible due to the difficulty of estimating tissue optical properties and modelling light propagation in complex tissue geometries. Here, we experimentally investigate the performance of planar (non-tomographic) MSI and FLT multiplexing for the quantitative recovery of multiple near-infrared fluorophores embedded in 4-8 mm thick tissue. We show that FLT multiplexing provides a superior quantification accuracy (error < 10%) compared to MSI (error = 20-107%) in tissue. The error rates for MSI increased with tissue thickness and can be directly attributed to the spectral redshift induced cross-talk between emission spectra. Our data indicate that planar FLT multiplexing can provide high quantification accuracy in thick biological tissue without a need for optical property estimation, thereby offering an important validation tool for rapid quantification of fluorophore concentrations in bulk tissue.
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12
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Optimization of Advanced Live-Cell Imaging through Red/Near-Infrared Dye Labeling and Fluorescence Lifetime-Based Strategies. Int J Mol Sci 2021; 22:ijms222011092. [PMID: 34681761 PMCID: PMC8537913 DOI: 10.3390/ijms222011092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/08/2021] [Accepted: 10/09/2021] [Indexed: 12/30/2022] Open
Abstract
Fluorescence microscopy is essential for a detailed understanding of cellular processes; however, live-cell preservation during imaging is a matter of debate. In this study, we proposed a guide to optimize advanced light microscopy approaches by reducing light exposure through fluorescence lifetime (τ) exploitation of red/near-infrared dyes. Firstly, we characterized key instrumental elements which revealed that red/near-infrared laser lines with an 86x (Numerical Aperture (NA) = 1.2, water immersion) objective allowed high transmission of fluorescence signals, low irradiance and super-resolution. As a combination of two technologies, i.e., vacuum tubes (e.g., photomultiplier) and semiconductor microelectronics (e.g., avalanche photodiode), type S, X and R of hybrid detectors (HyD-S, HyD-X and HyD-R) were particularly adapted for red/near-infrared photon counting and τ separation. Secondly, we tested and compared lifetime-based imaging including coarse τ separation for confocal microscopy, fitting and phasor plot analysis for fluorescence lifetime microscopy (FLIM), and lifetimes weighting for enhanced stimulated emission depletion (STED) nanoscopy, in light of red/near-infrared multiplexing. Mainly, we showed that the choice of appropriate imaging approach may depend on fluorochrome number, together with their spectral/lifetime characteristics and STED compatibility. Photon-counting mode and sensitivity of HyDs together with phasor plot analysis of fluorescence lifetimes enabled the flexible and fast imaging of multi-labeled living H28 cells. Therefore, a combination of red/near-infrared dyes labeling with lifetime-based strategies offers new perspectives for live-cell imaging by enhancing sample preservation through acquisition time and light exposure reduction.
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