1
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Ioannou IA, Brooks NJ, Kuimova MK, Elani Y. Visualizing Actin Packing and the Effects of Actin Attachment on Lipid Membrane Viscosity Using Molecular Rotors. JACS AU 2024; 4:2041-2049. [PMID: 38818078 PMCID: PMC11134356 DOI: 10.1021/jacsau.4c00237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 06/01/2024]
Abstract
The actin cytoskeleton and its elaborate interplay with the plasma membrane participate in and control numerous biological processes in eukaryotic cells. Malfunction of actin networks and changes in their dynamics are related to various diseases, from actin myopathies to uncontrolled cell growth and tumorigenesis. Importantly, the biophysical and mechanical properties of actin and its assemblies are deeply intertwined with the biological functions of the cytoskeleton. Novel tools to study actin and its associated biophysical features are, therefore, of prime importance. Here we develop a new approach which exploits fluorescence lifetime imaging microscopy (FLIM) and environmentally sensitive fluorophores termed molecular rotors, acting as quantitative microviscosity sensors, to monitor dynamic viscoelastic properties of both actin structures and lipid membranes. In order to reproduce a minimal actin cortex in synthetic cell models, we encapsulated and attached actin networks to the lipid bilayer of giant unilamellar vesicles (GUVs). Using a cyanine-based molecular rotor, DiSC2(3), we show that different types of actin bundles are characterized by distinct packing, which can be spatially resolved using FLIM. Similarly, we show that a lipid bilayer-localized molecular rotor can monitor the effects of attaching cross-linked actin networks to the lipid membrane, revealing an increase in membrane viscosity upon actin attachment. Our approach bypasses constraints associated with existing methods for actin imaging, many of which lack the capability for direct visualization of biophysical properties. It can therefore contribute to a deeper understanding of the role that actin plays in fundamental biological processes and help elucidate the underlying biophysics of actin-related diseases.
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Affiliation(s)
- Ion A. Ioannou
- Department
of Chemistry, Imperial College London, Molecular
Sciences Research Hub, London W12 0BZ, U.K.
- Department
of Chemical Engineering, Imperial College
London, South Kensington, London SW7 2AZ, U.K.
| | - Nickolas J. Brooks
- Department
of Chemistry, Imperial College London, Molecular
Sciences Research Hub, London W12 0BZ, U.K.
| | - Marina K. Kuimova
- Department
of Chemistry, Imperial College London, Molecular
Sciences Research Hub, London W12 0BZ, U.K.
| | - Yuval Elani
- Department
of Chemical Engineering, Imperial College
London, South Kensington, London SW7 2AZ, U.K.
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2
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Sperber J, Zachem TJ, Prakash R, Owolo E, Yamamoto K, Nguyen AD, Hockenberry H, Ross WA, Herndon JE, Codd PJ, Goodwin CR. A blinded study using laser induced endogenous fluorescence spectroscopy to differentiate ex vivo spine tumor, healthy muscle, and healthy bone. Sci Rep 2024; 14:1921. [PMID: 38253556 PMCID: PMC10803777 DOI: 10.1038/s41598-023-50995-4] [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: 07/11/2023] [Accepted: 12/28/2023] [Indexed: 01/24/2024] Open
Abstract
Ten patients undergoing surgical resection for spinal tumors were selected. Samples of tumor, muscle, and bone were resected, de-identified by the treating surgeon, and then scanned with the TumorID technology ex vivo. This study investigates whether TumorID technology is able to differentiate three different human clinical fresh tissue specimens: spine tumor, normal muscle, and normal bone. The TumorID technology utilizes a 405 nm excitation laser to target endogenous fluorophores, thereby allowing for the detection of tissue based on emission spectra. Metabolic profiles of tumor and healthy tissue vary, namely NADH (bound and free emission peak, respectively: 487 nm, 501 nm) and FAD (emission peak: 544) are endogenous fluorophores with distinct concentrations in tumor and healthy tissue. Emission spectra analyzed consisted of 74 scans of spine tumor, 150 scans of healthy normal bone, and 111 scans of healthy normal muscle. An excitation wavelength of 405 nm was used to obtain emission spectra from tissue as previously described. Emission spectra consisted of approximately 1400 wavelength intensity pairs between 450 and 750 nm. Kruskal-Wallis tests were conducted comparing AUC distributions for each treatment group, α = 0.05. Spectral signatures varied amongst the three different tissue types. All pairwise comparisons among tissues for Free NADH were statistically significant (Tumor vs. Muscle: p = 0.0006, Tumor vs. Bone: p < 0.0001, Bone vs. Muscle: p = 0.0357). The overall comparison of tissues for FAD (506.5-581.5 nm) was also statistically significant (p < 0.0001), with two pairwise comparisons being statistically significant (Tumor vs. Muscle: p < 0.0001, Tumor vs. Bone: p = 0.0045, Bone vs. Muscle: p = 0.249). These statistically significant differences were maintained when stratifying tumor into metastatic carcinoma (N = 57) and meningioma (N = 17). TumorID differentiates tumor tissue from normal bone and normal muscle providing further clinical evidence of its efficacy as a tissue identification tool. Future studies should evaluate TumorID's ability to serve as an adjunctive tool for intraoperative assessment of surgical margins and surgical decision-making.
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Affiliation(s)
- Jacob Sperber
- Department of Neurosurgery, Duke University School of Medicine, Durham, USA
| | - Tanner J Zachem
- Department of Neurosurgery, Duke University School of Medicine, Durham, USA
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, USA
| | - Ravi Prakash
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, USA
| | - Edwin Owolo
- Department of Neurosurgery, Duke University School of Medicine, Durham, USA
| | - Kent Yamamoto
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, USA
| | - Annee D Nguyen
- Department of Neurosurgery, Duke University School of Medicine, Durham, USA
| | | | - Weston A Ross
- Department of Neurosurgery, Duke University School of Medicine, Durham, USA
| | - James E Herndon
- Department of Biostatistics & Bioinformatics, Duke University School of Medicine, Durham, USA
| | - Patrick J Codd
- Department of Neurosurgery, Duke University School of Medicine, Durham, USA
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, USA
- Duke Cancer Institute, Duke University Medical Center, 200 Trent Drive DUMC 3807, Durham, NC, 27710, USA
| | - C Rory Goodwin
- Department of Neurosurgery, Duke University School of Medicine, Durham, USA.
- Duke Cancer Institute, Duke University Medical Center, 200 Trent Drive DUMC 3807, Durham, NC, 27710, USA.
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3
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Valls PO, Esposito A. Signalling dynamics, cell decisions, and homeostatic control in health and disease. Curr Opin Cell Biol 2022; 75:102066. [PMID: 35245783 PMCID: PMC9097822 DOI: 10.1016/j.ceb.2022.01.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 11/13/2022]
Abstract
Cell signalling engenders cells with the capability to receive and process information from the intracellular and extracellular environments, trigger and execute biological responses, and communicate with each other. Ultimately, cell signalling is responsible for maintaining homeostasis at the cellular, tissue and systemic level. For this reason, cell signalling is a topic of intense research efforts aimed to elucidate how cells coordinate transitions between states in developing and adult organisms in physiological and pathological conditions. Here, we review current knowledge of how cell signalling operates at multiple spatial and temporal scales, focusing on how single-cell analytical techniques reveal mechanisms underpinning cell-to-cell variability, signalling plasticity, and collective cellular responses.
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Affiliation(s)
- Pablo Oriol Valls
- MRC Cancer Unit, University of Cambridge, Cambridge, CB2 0XZ, United Kingdom
| | - Alessandro Esposito
- MRC Cancer Unit, University of Cambridge, Cambridge, CB2 0XZ, United Kingdom; Centre for Genome Engineering and Maintenance, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, United Kingdom.
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4
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San Martín A, Arce-Molina R, Aburto C, Baeza-Lehnert F, Barros LF, Contreras-Baeza Y, Pinilla A, Ruminot I, Rauseo D, Sandoval PY. Visualizing physiological parameters in cells and tissues using genetically encoded indicators for metabolites. Free Radic Biol Med 2022; 182:34-58. [PMID: 35183660 DOI: 10.1016/j.freeradbiomed.2022.02.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 02/07/2023]
Abstract
The study of metabolism is undergoing a renaissance. Since the year 2002, over 50 genetically-encoded fluorescent indicators (GEFIs) have been introduced, capable of monitoring metabolites with high spatial/temporal resolution using fluorescence microscopy. Indicators are fusion proteins that change their fluorescence upon binding a specific metabolite. There are indicators for sugars, monocarboxylates, Krebs cycle intermediates, amino acids, cofactors, and energy nucleotides. They permit monitoring relative levels, concentrations, and fluxes in living systems. At a minimum they report relative levels and, in some cases, absolute concentrations may be obtained by performing ad hoc calibration protocols. Proper data collection, processing, and interpretation are critical to take full advantage of these new tools. This review offers a survey of the metabolic indicators that have been validated in mammalian systems. Minimally invasive, these indicators have been instrumental for the purposes of confirmation, rebuttal and discovery. We envision that this powerful technology will foster metabolic physiology.
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Affiliation(s)
- A San Martín
- Centro de Estudios Científicos (CECs), Valdivia, Chile.
| | - R Arce-Molina
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - C Aburto
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | | | - L F Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - Y Contreras-Baeza
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - A Pinilla
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - I Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - D Rauseo
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - P Y Sandoval
- Centro de Estudios Científicos (CECs), Valdivia, Chile
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5
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Zou G, Yu W, Xu Y, Li Y, Hu R, Qu J, Liu L. Investigation of apoptosis based on fluorescence lifetime imaging microscopy with a mitochondria-targeted viscosity probe. RSC Adv 2021; 11:38750-38758. [PMID: 35493215 PMCID: PMC9044426 DOI: 10.1039/d1ra06697h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/16/2021] [Indexed: 12/20/2022] Open
Abstract
Cell apoptosis detection based on the functionality changes of cellular organelles, such as mitochondria, offers a quantitative method compared to morphology-based detection. However, the conventional detection methods for potential variation of the mitochondrial membrane based on fluorescence spectrum changes cannot offer a precise quantification of the degree of apoptosis. Here, a mitochondria-targeted two-photon viscosity probe (TPA-Mit), which sensitively responds to viscosity variations with fluorescence lifetime changes, is designed to detect the viscosity of mitochondria. Noteworthily, the proposed phasor fluorescence lifetime imaging microscopy (phasor-FLIM) allows for more precise quantification (in terms of smaller uncertainty) when estimating the degree of apoptosis with a microviscosity probe. The experimental results of SKOV-3 cells show that the fluorescence lifetime of mitochondria-targeted TPA-Mit increased from 550 ps to 800 ps after 24 hours of paclitaxel (PTX)-induced apoptosis. We believe that our method provides a new means for the measurement of cellular microviscosity and apoptosis monitoring at early stages. Here we designed a mitochondria-targeted two-photon viscosity probe (TPA-Mit), which sensitively responds to viscosity variations with fluorescence lifetime changes.![]()
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Affiliation(s)
- Gengjin Zou
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province, Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University China
| | - Wenhui Yu
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province, Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University China
| | - Yunjian Xu
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province, Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University China
| | - Yanping Li
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province, Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University China
| | - Rui Hu
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province, Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University China
| | - Junle Qu
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province, Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University China
| | - Liwei Liu
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province, Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University China
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6
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Sorrells JE, Iyer RR, Yang L, Chaney EJ, Marjanovic M, Tu H, Boppart SA. Single-photon peak event detection (SPEED): a computational method for fast photon counting in fluorescence lifetime imaging microscopy. OPTICS EXPRESS 2021; 29:37759-37775. [PMID: 34808842 PMCID: PMC8687103 DOI: 10.1364/oe.439675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Fluorescence lifetime imaging microscopy (FLIM) characterizes samples by examining the temporal properties of fluorescence emission, providing useful contrast within samples based on the local physical and biochemical environment of fluorophores. Despite this, FLIM applications have been limited in scope by either poor accuracy or long acquisition times. Here, we present a method for computational single-photon counting of directly sampled time-domain FLIM data that is capable of accurate fluorescence lifetime and intensity measurements while acquiring over 160 Mega-counts-per-second with sub-nanosecond time resolution between consecutive photon counts. We demonstrate that our novel method of Single-photon PEak Event Detection (SPEED) is more accurate than direct pulse sampling and faster than established photon counting FLIM methods. We further show that SPEED can be implemented for imaging and quantifying samples that benefit from higher -throughput and -dynamic range imaging with real-time GPU-accelerated processing and use this capability to examine the NAD(P)H-related metabolic dynamics of apoptosis in human breast cancer cells. Computational methods for photon counting such as SPEED open up more opportunities for fast and accurate FLIM imaging and additionally provide a basis for future innovation into alternative FLIM techniques.
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Affiliation(s)
- Janet E. Sorrells
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Rishyashring R. Iyer
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Lingxiao Yang
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Eric J. Chaney
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Marina Marjanovic
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Haohua Tu
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Stephen A. Boppart
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Cancer Center at Illinois, Urbana, IL 61801, USA
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7
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Khaliduzzaman A, Omwange KA, Al Riza DF, Konagaya K, Kamruzzaman M, Alom MS, Gao T, Saito Y, Kondo N. Antioxidant assessment of agricultural produce using fluorescence techniques: a review. Crit Rev Food Sci Nutr 2021:1-12. [PMID: 34702101 DOI: 10.1080/10408398.2021.1992747] [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: 10/20/2022]
Abstract
The study of bioactive compounds like food antioxidants is getting huge attention and curiosity by researchers and other relevant stakeholders (e.g., food and pharmaceutical industries) due to their health benefits. However, the currently available protocols to estimate the antioxidant activity of foods are time-consuming, destructive, require complex procedures for sample preparation, need technical persons, and not possible for real-time application, which are very important for large-scale or industrial applications. On the other hand, fluorescence spectroscopy and imaging techniques are relatively new, fast, mostly nondestructive, and possible to apply real-time to detect the antioxidants of foods. However, there is no review article on fluorescence techniques for estimating antioxidants in agricultural produces. Therefore, the present review comprehensively summarizes the overview of fluorescence phenomena, techniques (i.e., spectroscopy and computer vision), and their potential to monitor antioxidants in fruits and vegetables. Finally, opportunities and challenges of fluorescence techniques are described toward developing next-generation protocols for antioxidants measurement. Fluorescence techniques (both spectroscopy and imaging) are simpler and faster than available traditional methods of antioxidants measurement. Moreover, the fluorescence imaging technique has the potential to apply in real-time antioxidant identification in agricultural produce such as fruits and vegetables. Therefore, this technique might be used as a next-generation protocol for qualitative and quantitative antioxidants measurement after improvements like new material technologies for sensor (detector) and light sources for higher sensitivity and reduce the cost of implementing real-world applications.
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Affiliation(s)
- Alin Khaliduzzaman
- Laboratory of Bio-sensing Engineering, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.,Department of Food Engineering and Technology, Sylhet Agricultural University, Sylhet, Bangladesh
| | - Ken Abamba Omwange
- Laboratory of Bio-sensing Engineering, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Dimas Firmanda Al Riza
- Department of Agricultural Engineering, Faculty of Agricultural Technology, University of Brawijaya, Malang, Indonesia
| | - Keiji Konagaya
- Faculty of Corroborative Regional Innovation, Ehime University, Matsuyama, Ehime, Japan
| | - Mohammed Kamruzzaman
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Md Siddik Alom
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA
| | - Tianqi Gao
- Laboratory of Bio-sensing Engineering, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yoshito Saito
- Laboratory of Bio-sensing Engineering, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Naoshi Kondo
- Laboratory of Bio-sensing Engineering, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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8
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Bowman AJ, Kasevich MA. Resonant Electro-Optic Imaging for Microscopy at Nanosecond Resolution. ACS NANO 2021; 15:16043-16054. [PMID: 34546704 DOI: 10.1021/acsnano.1c04470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We demonstrate an electro-optic wide-field method to enable fluorescence lifetime microscopy (FLIM) with high throughput and single-molecule sensitivity. Resonantly driven Pockels cells are used to efficiently gate images at 39 MHz, allowing fluorescence lifetime to be captured on standard camera sensors. Lifetime imaging of single molecules is enabled in wide field with exposure times of less than 100 ms. This capability allows combination of wide-field FLIM with single-molecule super-resolution localization microscopy. Fast single-molecule dynamics such as FRET and molecular binding events are captured from wide-field images without prior spatial knowledge. A lifetime sensitivity of 1.9 times the photon shot-noise limit is achieved, and high throughput is shown by acquiring wide-field FLIM images with millisecond exposure and >108 photons per frame. Resonant electro-optic FLIM allows lifetime contrast in any wide-field microscopy method.
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Affiliation(s)
- Adam J Bowman
- Physics Department, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305, United States
| | - Mark A Kasevich
- Physics Department, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305, United States
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9
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Giampetraglia M, Weigelin B. Recent advances in intravital microscopy for preclinical research. Curr Opin Chem Biol 2021; 63:200-208. [PMID: 34274700 DOI: 10.1016/j.cbpa.2021.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 05/08/2021] [Accepted: 05/14/2021] [Indexed: 12/14/2022]
Abstract
Intravital microscopy (IVM) has revolutionized our understanding of single-cell behavior in complex tissues by enabling real-time observation of molecular and cellular processes in their natural environment. In preclinical research, IVM has emerged as a standard tool for mechanistic studies of therapy response and the rational design of new treatment strategies. Technological developments keep expanding the imaging depth and quality that can be achieved in living tissue, and the maturation of imaging modalities such as fluorescence and phosphorescence lifetime imaging facilitates co-registration of individual cell dynamics with metabolic tissue states. Correlation of IVM with mesoscopic and macroscopic imaging modalities further promotes the translation of mechanistic insights gained by IVM into clinically relevant information. This review highlights some of the recent advances in IVM that have made the transition from experimental optical techniques to practical applications in basic and preclinical research.
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Affiliation(s)
- Martina Giampetraglia
- David H. Koch Center for Applied Research of Genitourinary Cancers, Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA
| | - Bettina Weigelin
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tübingen, Tübingen, Germany; Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", University of Tübingen, Germany.
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10
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Trinh AL, Esposito A. Biochemical resolving power of fluorescence lifetime imaging: untangling the roles of the instrument response function and photon-statistics. BIOMEDICAL OPTICS EXPRESS 2021; 12:3775-3788. [PMID: 34457379 PMCID: PMC8367261 DOI: 10.1364/boe.428070] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/21/2021] [Accepted: 05/28/2021] [Indexed: 05/29/2023]
Abstract
A deeper understanding of spatial resolution has led to innovations in microscopy and the disruption of biomedical research, as with super-resolution microscopy. To foster similar advances in time-resolved and spectral imaging, we have previously introduced the concept of 'biochemical resolving power' in fluorescence microscopy. Here, we apply those concepts to investigate how the instrument response function (IRF), sampling conditions, and photon-statistics limit the biochemical resolution of fluorescence lifetime microscopy. Using Fisher information analysis and Monte Carlo simulations, we reveal the complex dependencies between photon-statistics and the IRF, permitting us to quantify resolution limits that have been poorly understood (e.g., the minimum resolvable decay time for a given width of the IRF and photon-statistics) or previously underappreciated (e.g., optimization of the IRF for biochemical detection). With this work, we unravel common misunderstandings on the role of the IRF and provide theoretical insights with significant practical implications on the design and use of time-resolved instrumentation.
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Affiliation(s)
- Andrew L Trinh
- MRC Cancer Unit, University of Cambridge, Cambridge, United Kingdom
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11
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Dmitriev RI, Intes X, Barroso MM. Luminescence lifetime imaging of three-dimensional biological objects. J Cell Sci 2021; 134:1-17. [PMID: 33961054 PMCID: PMC8126452 DOI: 10.1242/jcs.254763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A major focus of current biological studies is to fill the knowledge gaps between cell, tissue and organism scales. To this end, a wide array of contemporary optical analytical tools enable multiparameter quantitative imaging of live and fixed cells, three-dimensional (3D) systems, tissues, organs and organisms in the context of their complex spatiotemporal biological and molecular features. In particular, the modalities of luminescence lifetime imaging, comprising fluorescence lifetime imaging (FLI) and phosphorescence lifetime imaging microscopy (PLIM), in synergy with Förster resonance energy transfer (FRET) assays, provide a wealth of information. On the application side, the luminescence lifetime of endogenous molecules inside cells and tissues, overexpressed fluorescent protein fusion biosensor constructs or probes delivered externally provide molecular insights at multiple scales into protein-protein interaction networks, cellular metabolism, dynamics of molecular oxygen and hypoxia, physiologically important ions, and other physical and physiological parameters. Luminescence lifetime imaging offers a unique window into the physiological and structural environment of cells and tissues, enabling a new level of functional and molecular analysis in addition to providing 3D spatially resolved and longitudinal measurements that can range from microscopic to macroscopic scale. We provide an overview of luminescence lifetime imaging and summarize key biological applications from cells and tissues to organisms.
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Affiliation(s)
- Ruslan I. Dmitriev
- Tissue Engineering and Biomaterials Group, Department of
Human Structure and Repair, Faculty of Medicine and Health Sciences,
Ghent University, Ghent 9000,
Belgium
| | - Xavier Intes
- Department of Biomedical Engineering, Center for
Modeling, Simulation and Imaging for Medicine (CeMSIM),
Rensselaer Polytechnic Institute, Troy, NY
12180-3590, USA
| | - Margarida M. Barroso
- Department of Molecular and Cellular
Physiology, Albany Medical College,
Albany, NY 12208, USA
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12
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Bitton A, Sambrano J, Valentino S, Houston JP. A Review of New High-Throughput Methods Designed for Fluorescence Lifetime Sensing From Cells and Tissues. FRONTIERS IN PHYSICS 2021; 9:648553. [PMID: 34007839 PMCID: PMC8127321 DOI: 10.3389/fphy.2021.648553] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Though much of the interest in fluorescence in the past has been on measuring spectral qualities such as wavelength and intensity, there are two other highly useful intrinsic properties of fluorescence: lifetime (or decay) and anisotropy (or polarization). Each has its own set of unique advantages, limitations, and challenges in detection when it comes to use in biological studies. This review will focus on the property of fluorescence lifetime, providing a brief background on instrumentation and theory, and examine the recent advancements and applications of measuring lifetime in the fields of high-throughput fluorescence lifetime imaging microscopy (HT-FLIM) and time-resolved flow cytometry (TRFC). In addition, the crossover of these two methods and their outlooks will be discussed.
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13
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Chacko JV, Lee HN, Wu W, Otegui MS, Eliceiri KW. Hyperdimensional Imaging Contrast Using an Optical Fiber. SENSORS 2021; 21:s21041201. [PMID: 33572130 PMCID: PMC7914562 DOI: 10.3390/s21041201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/01/2021] [Accepted: 02/05/2021] [Indexed: 11/16/2022]
Abstract
Fluorescence properties of a molecule can be used to study the structural and functional nature of biological processes. Physical properties, including fluorescence lifetime, emission spectrum, emission polarization, and others, help researchers probe a molecule, produce desired effects, and infer causes and consequences. Correlative imaging techniques such as hyperdimensional imaging microscopy (HDIM) combine the physical properties and biochemical states of a fluorophore. Here we present a fiber-based imaging system that can generate hyper-dimensional contrast by combining multiple fluorescence properties into a single fluorescence lifetime decay curve. Fluorescence lifetime imaging microscopy (FLIM) with controlled excitation polarization and temporally dispersed emission can generate a spectrally coded, polarization-filtered lifetime distribution for a pixel. This HDIM scheme generates a better contrast between different molecules than that from individual techniques. This setup uses only a single detector and is simpler to implement, modular, cost-efficient, and adaptable to any existing FLIM microscope. We present higher contrast data from Arabidopsis thaliana epidermal cells based on intrinsic anthocyanin emission properties under multiphoton excitation. This work lays the foundation for an alternative hyperdimensional imaging system and demonstrates that contrast-based imaging is useful to study cellular heterogeneity in biological samples.
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Affiliation(s)
- Jenu V. Chacko
- Center for Quantitative Cell Imaging, University of Wisconsin, Madison, WI 53706, USA; (J.V.C.); (H.N.L.); (W.W.); (M.S.O.)
| | - Han Nim Lee
- Center for Quantitative Cell Imaging, University of Wisconsin, Madison, WI 53706, USA; (J.V.C.); (H.N.L.); (W.W.); (M.S.O.)
- Department of Botany, University of Wisconsin, Madison, WI, 53706, USA
| | - Wenxin Wu
- Center for Quantitative Cell Imaging, University of Wisconsin, Madison, WI 53706, USA; (J.V.C.); (H.N.L.); (W.W.); (M.S.O.)
| | - Marisa S. Otegui
- Center for Quantitative Cell Imaging, University of Wisconsin, Madison, WI 53706, USA; (J.V.C.); (H.N.L.); (W.W.); (M.S.O.)
- Department of Botany, University of Wisconsin, Madison, WI, 53706, USA
| | - Kevin W. Eliceiri
- Center for Quantitative Cell Imaging, University of Wisconsin, Madison, WI 53706, USA; (J.V.C.); (H.N.L.); (W.W.); (M.S.O.)
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53706, USA
- Department of Medical Physics, University of Wisconsin, Madison, WI 53706, USA
- Morgridge Institute for Research, University of Wisconsin, Madison, WI 53706, USA
- Correspondence:
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Ameer-Beg S, Suhling K, Kuimova M. Special issue on fluorescence lifetime imaging (FLIM): from fundamentals to applications. Methods Appl Fluoresc 2020; 8:040401. [PMID: 33021203 DOI: 10.1088/2050-6120/abad19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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15
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Datta R, Heaster TM, Sharick JT, Gillette AA, Skala MC. Fluorescence lifetime imaging microscopy: fundamentals and advances in instrumentation, analysis, and applications. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-43. [PMID: 32406215 PMCID: PMC7219965 DOI: 10.1117/1.jbo.25.7.071203] [Citation(s) in RCA: 305] [Impact Index Per Article: 76.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/24/2020] [Indexed: 05/18/2023]
Abstract
SIGNIFICANCE Fluorescence lifetime imaging microscopy (FLIM) is a powerful technique to distinguish the unique molecular environment of fluorophores. FLIM measures the time a fluorophore remains in an excited state before emitting a photon, and detects molecular variations of fluorophores that are not apparent with spectral techniques alone. FLIM is sensitive to multiple biomedical processes including disease progression and drug efficacy. AIM We provide an overview of FLIM principles, instrumentation, and analysis while highlighting the latest developments and biological applications. APPROACH This review covers FLIM principles and theory, including advantages over intensity-based fluorescence measurements. Fundamentals of FLIM instrumentation in time- and frequency-domains are summarized, along with recent developments. Image segmentation and analysis strategies that quantify spatial and molecular features of cellular heterogeneity are reviewed. Finally, representative applications are provided including high-resolution FLIM of cell- and organelle-level molecular changes, use of exogenous and endogenous fluorophores, and imaging protein-protein interactions with Förster resonance energy transfer (FRET). Advantages and limitations of FLIM are also discussed. CONCLUSIONS FLIM is advantageous for probing molecular environments of fluorophores to inform on fluorophore behavior that cannot be elucidated with intensity measurements alone. Development of FLIM technologies, analysis, and applications will further advance biological research and clinical assessments.
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Affiliation(s)
- Rupsa Datta
- Morgridge Institute for Research, Madison, Wisconsin, United States
| | - Tiffany M. Heaster
- Morgridge Institute for Research, Madison, Wisconsin, United States
- University of Wisconsin, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Joe T. Sharick
- Morgridge Institute for Research, Madison, Wisconsin, United States
| | - Amani A. Gillette
- Morgridge Institute for Research, Madison, Wisconsin, United States
- University of Wisconsin, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Melissa C. Skala
- Morgridge Institute for Research, Madison, Wisconsin, United States
- University of Wisconsin, Department of Biomedical Engineering, Madison, Wisconsin, United States
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Sameni S, Zhang R, Digman MA. The Phasor FLIM Method Reveals a Link Between a Change in Energy Metabolism and mHtt protein spread in Healthy Mammalian Cells when Co-cultured with Huntington Diseased Cells. Methods Appl Fluoresc 2020; 9. [PMID: 32235053 DOI: 10.1088/2050-6120/ab854d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 03/31/2020] [Indexed: 11/12/2022]
Abstract
Huntington Disease (HD) is a late-onset autosomal neurodegenerative disease characterized by the aggregations of mutant Huntingtin proteins (mHTT). A glutamine stretch (PolyQ) at the N-terminal of the Huntingtin protein is generated by the abnormal expansion of CAG trinucleotide repeats in exon 1 of the HTT gene. While the resulting polyQ aggregates are the predominate feature of HD , the intercellular spread of the expanded protein and the effect upon this transfer inside healthy cells have not yet fully understood. Here, we have employed the phasor Fluorescence Lifetime Imaging Microscopy (FLIM) method to measure NADH fluorescence lifetime change after the internalization of the PolyQ protein. Based on our analysis, we have found a significant decrease in the fraction of bound NADH in both cytoplasmic and nucleus regions when cells are co-cultured or when healthy cells uptake the supernatant containing polyQ proteins and aggregates. Overall, our FLIM study combined with confocal fluorescence imaging visualizes the absorption of the mutant Htt protein aggregates which results in a distinct NADH fluorescence lifetime between control cells and acceptor cells. These studies show, for the first time, the influence of how neighboring cells expressing the expanded Htt protein can regulate energy metabolism in healthy cells.
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Affiliation(s)
- Sara Sameni
- CNL, Salk Institute, La Jolla, California, UNITED STATES
| | - Run Zhang
- Surgery, University of California San Francisco, San Francisco, California, UNITED STATES
| | - Michelle A Digman
- Biomedical Engineering, University of California Irvine, University of California, Irvine, CA, United States, Irvine, California, UNITED STATES
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Esposito A. How many photons are needed for FRET imaging? BIOMEDICAL OPTICS EXPRESS 2020; 11:1186-1202. [PMID: 32133242 PMCID: PMC7041441 DOI: 10.1364/boe.379305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 12/15/2019] [Accepted: 01/21/2020] [Indexed: 06/10/2023]
Abstract
Förster resonance energy transfer (FRET) imaging is an essential analytical method in biomedical research. The limited photon-budget experimentally available, however, imposes compromises between spatiotemporal and biochemical resolutions, photodamage and phototoxicity. The study of photon-statistics in biochemical imaging is thus important in guiding the efficient design of instrumentation and assays. Here, we show a comparative analysis of photon-statistics in FRET imaging demonstrating how the precision of FRET imaging varies vastly with imaging parameters. Therefore, we provide analytical and numerical tools for assay optimization. Fluorescence lifetime imaging microscopy (FLIM) is a very robust technique with excellent photon-efficiencies. However, we show that also intensity-based FRET imaging can reach high precision by utilizing information from both donor and acceptor fluorophores.
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Affiliation(s)
- Alessandro Esposito
- MRC Cancer Unit, University of Cambridge, Biomedical Campus, Cambridge, CB20XY, UK
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