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Rathbone E, Fu D. Quantitative Optical Imaging of Oxygen in Brain Vasculature. J Phys Chem B 2024. [PMID: 38991095 DOI: 10.1021/acs.jpcb.4c01277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
The intimate relationship between neuronal activity and cerebral oxygenation underpins fundamental brain functions like cognition, sensation, and motor control. Optical imaging offers a noninvasive approach to assess brain oxygenation and often serves as an indirect proxy for neuronal activity. However, deciphering neurovascular coupling─the intricate interplay between neuronal activity, blood flow, and oxygen delivery─necessitates independent, high spatial resolution, and high temporal resolution measurements of both microvasculature oxygenation and neuronal activation. This Perspective examines the established optical techniques employed for brain oxygen imaging, specifically functional near-infrared spectroscopy, photoacoustic imaging, optical coherence tomography, and two-photon phosphorescent lifetime microscopy, highlighting their fundamental principles, strengths, and limitations. Several other emerging optical techniques are also introduced. Finally, we discuss key technological challenges and future directions for quantitative optical oxygen imaging, paving the way for a deeper understanding of oxygen metabolism in the brain.
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Affiliation(s)
- Emily Rathbone
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Dan Fu
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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2
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Huang Z, Yang S, Li C, Xie X, Wang Y. The effects of intermittent hypoxic training on the aerobic capacity of exercisers: a systemic review and meta-analysis. BMC Sports Sci Med Rehabil 2023; 15:174. [PMID: 38115083 PMCID: PMC10731756 DOI: 10.1186/s13102-023-00784-3] [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: 04/18/2023] [Accepted: 12/07/2023] [Indexed: 12/21/2023]
Abstract
OBJECTIVE To systematically review the effects of intermittent hypoxic training on the aerobic capacity of exercisers. METHODS PubMed, Embase, The Cochrane Library, and Web of Science databases were electronically searched to collect studies on the effects of intermittent hypoxic training on the aerobic capacity of exercisers from January 1, 2000, to January 12, 2023. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies. Then, meta-analysis was performed by using Stata SE 16.0 software. RESULTS A total of 19 articles from 27 studies were included. The results of the meta-analysis showed that compared with the control group, the intermittent hypoxic training group had significantly increased maximal oxygen uptake [weighted mean difference = 3.20 (95%CI: 1.33 ~ 5.08)] and hemoglobin [weighted mean difference = 0.25 (95%CI: 0.04 ~ 0.45)]. CONCLUSION Intermittent hypoxic training can significantly improve the aerobic capacity of exercisers. Due to the limited quantity and quality of the included studies, more high-quality studies are needed to verify the above conclusion.
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Affiliation(s)
- Zhihao Huang
- School of Big Data and Fundamental Sciences, Shandong Institute of Petroleum and Chemical Technology, Dongying, China
| | - Shulin Yang
- School of Big Data and Fundamental Sciences, Shandong Institute of Petroleum and Chemical Technology, Dongying, China
| | - Chunyang Li
- School of Sports Sciences, Nanjing Normal University, Nanjing, China.
| | - Xingchao Xie
- School of Big Data and Fundamental Sciences, Shandong Institute of Petroleum and Chemical Technology, Dongying, China
| | - Yongming Wang
- School of Big Data and Fundamental Sciences, Shandong Institute of Petroleum and Chemical Technology, Dongying, China
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3
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Wang E, Whitcomb LA, Chicco AJ, Wilson JW. Transient absorption spectroscopy and imaging of redox in muscle mitochondria. BIOMEDICAL OPTICS EXPRESS 2022; 13:2103-2116. [PMID: 35519286 PMCID: PMC9045930 DOI: 10.1364/boe.452559] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 03/03/2022] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
Mitochondrial redox is an important indicator of cell metabolism and health, with implications in cancer, diabetes, aging, neurodegenerative diseases, and mitochondrial disease. The most common method to observe redox of individual cells and mitochondria is through fluorescence of NADH and FAD+, endogenous cofactors serve as electron transport inputs to the mitochondrial respiratory chain. Yet this leaves out redox within the respiratory chain itself. To a degree, the missing information can be filled in by exogenous fluorophores, but at the risk of disturbed mitochondrial permeability and respiration. Here we show that variations in respiratory chain redox can be detected up by visible-wavelength transient absorption microscopy (TAM). In TAM, the selection of pump and probe wavelengths can provide multiphoton imaging contrast between non-fluorescent molecules. Here, we applied TAM with a pump at 520nm and probe at 450nm, 490nm, and 620nm to elicit redox contrast from mitochondrial respiratory chain hemeproteins. Experiments were performed with reduced and oxidized preparations of isolated mitochondria and whole muscle fibers, using mitochondrial fuels (malate, pyruvate, and succinate) to set up physiologically relevant oxidation levels. TAM images of muscle fibers were analyzed with multivariate curve resolution (MCR), revealing that the response at 620nm probe provides the best redox contrast and the most consistent response between whole cells and isolated mitochondria.
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Affiliation(s)
- Erkang Wang
- Department of Electrical & Computer
Engineering, Colorado State University,
1373 Campus Delivery, Fort Collins, CO 80523, USA
| | - Luke A. Whitcomb
- Department of Biomedical Sciences,
Colorado State University, 1601 Campus
Delivery, Fort Collins, CO 80523, USA
| | - Adam J. Chicco
- Department of Biomedical Sciences,
Colorado State University, 1601 Campus
Delivery, Fort Collins, CO 80523, USA
| | - Jesse W. Wilson
- Department of Electrical & Computer
Engineering, Colorado State University,
1373 Campus Delivery, Fort Collins, CO 80523, USA
- School of Biomedical Engineering,
Colorado State University, 1301 Campus
Delivery, Fort Collins, CO 80523, USA
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4
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Francis AT, Manifold B, Carlson EC, Hu R, Hill AH, Men S, Fu D. In vivo simultaneous nonlinear absorption Raman and fluorescence (SNARF) imaging of mouse brain cortical structures. Commun Biol 2022; 5:222. [PMID: 35273325 PMCID: PMC8913696 DOI: 10.1038/s42003-022-03166-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/08/2022] [Indexed: 12/03/2022] Open
Abstract
Label-free multiphoton microscopy is a powerful platform for biomedical imaging. Recent advancements have demonstrated the capabilities of transient absorption microscopy (TAM) for label-free quantification of hemoglobin and stimulated Raman scattering (SRS) microscopy for pathological assessment of label-free virtual histochemical staining. We propose the combination of TAM and SRS with two-photon excited fluorescence (TPEF) to characterize, quantify, and compare hemodynamics, vessel structure, cell density, and cell identity in vivo between age groups. In this study, we construct a simultaneous nonlinear absorption, Raman, and fluorescence (SNARF) microscope with the highest reported in vivo imaging depth for SRS and TAM at 250–280 μm to enable these multimodal measurements. Using machine learning, we predict capillary-lining cell identities with 90% accuracy based on nuclear morphology and capillary relationship. The microscope and methodology outlined herein provides an exciting route to study several research topics, including neurovascular coupling, blood-brain barrier, and neurodegenerative diseases. In this study a microscope is constructed that carries out simultaneous nonlinear absorption, Raman, and fluorescence (SNARF). Machine learning is then used to predict capillary-lining cell identities with 90% accuracy based on nuclear morphology and capillary relationship, which in combination with the developed microscope, can provide a means to study several fields such as neurovascular coupling.
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Affiliation(s)
- Andrew T Francis
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Bryce Manifold
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Elena C Carlson
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Ruoqian Hu
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Andrew H Hill
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Shuaiqian Men
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Dan Fu
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA.
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5
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Kaza N, Ojaghi A, Robles FE. Hemoglobin quantification in red blood cells via dry mass mapping based on UV absorption. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210112LR. [PMID: 34378368 PMCID: PMC8353376 DOI: 10.1117/1.jbo.26.8.086501] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/16/2021] [Indexed: 05/31/2023]
Abstract
SIGNIFICANCE The morphological properties and hemoglobin (Hb) content of red blood cells (RBCs) are essential biomarkers to diagnose or monitor various types of hematological disorders. Label-free mass mapping approaches enable accurate Hb quantification from individual cells, serving as promising alternatives to conventional hematology analyzers. Deep ultraviolet (UV) microscopy is one such technique that allows high-resolution, molecular imaging, and absorption-based mass mapping. AIM To compare UV absorption-based mass mapping at four UV wavelengths and understand variations across wavelengths and any assumptions necessary for accurate Hb quantification. APPROACH Whole blood smears are imaged with a multispectral UV microscopy system, and the RBCs' dry masses are computed. This approach is compared to quantitative phase imaging-based mass mapping using data from an interferometric UV imaging system. RESULTS Consistent Hb mass and mean corpuscular Hb values are obtained at all wavelengths, with the precision of the single-cell mass measurements being nearly identical at 220, 260, and 280 nm but slightly lower at 300 nm. CONCLUSIONS A full hematological analysis (including white blood cell identification and characterization, and Hb quantification) may be achieved using a single UV illumination wavelength, thereby improving the speed and cost-effectiveness.
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Affiliation(s)
- Nischita Kaza
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, Georgia, United States
| | - Ashkan Ojaghi
- Georgia Institute of Technology and Emory University, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
| | - Francisco E. Robles
- Georgia Institute of Technology and Emory University, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
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Zhang C, Aldana-Mendoza JA. Coherent Raman scattering microscopy for chemical imaging of biological systems. JPHYS PHOTONICS 2021. [DOI: 10.1088/2515-7647/abfd09] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Abstract
Coherent Raman scattering (CRS) processes, including both the coherent anti-Stokes Raman scattering and stimulated Raman scattering, have been utilized in state-of-the-art microscopy platforms for chemical imaging of biological samples. The key advantage of CRS microscopy over fluorescence microscopy is label-free, which is an attractive characteristic for modern biological and medical sciences. Besides, CRS has other advantages such as higher selectivity to metabolites, no photobleaching, and narrow peak width. These features have brought fast-growing attention to CRS microscopy in biological research. In this review article, we will first briefly introduce the history of CRS microscopy, and then explain the theoretical background of the CRS processes in detail using the classical approach. Next, we will cover major instrumentation techniques of CRS microscopy. Finally, we will enumerate examples of recent applications of CRS imaging in biological and medical sciences.
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7
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Jiang J, Grass D, Zhou Y, Warren WS, Fischer MC. Beyond intensity modulation: new approaches to pump-probe microscopy. OPTICS LETTERS 2021; 46:1474-1477. [PMID: 33720215 DOI: 10.1364/ol.417905] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
Pump-probe microscopy is an emerging nonlinear imaging technique based on high repetition rate lasers and fast intensity modulation. Here, we present new methods for pump-probe microscopy that keep the beam intensity constant and instead modulate the inter-pulse time delay or the relative polarization. These techniques can improve image quality for samples that have poor heat dissipation or long-lived radiative states and can selectively address nonlinear interactions in the sample. We experimentally demonstrate this approach and point out the advantages over conventional intensity modulation.
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Blake MJ, Colon BA, Calhoun TR. Leaving the Limits of Linearity for Light Microscopy. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2020; 124:24555-24565. [PMID: 34306294 PMCID: PMC8301257 DOI: 10.1021/acs.jpcc.0c07501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Nonlinear microscopy has enabled additional modalities for chemical contrast, deep penetration into biological tissues, and the ability to collect dynamics on ultrafast timescales across heterogenous samples. The additional light fields introduced to a sample offer seemingly endless possibilities for variation to optimize and customize experimentation and the extraction of physical insight. This perspective highlights three areas of growth in this diverse field: the collection of information across multiple timescales, the selective imaging of interfacial chemistry, and the exploitation of quantum behavior for future imaging directions. Future innovations will leverage the work of the studies reviewed here as well as address the current challenges presented.
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Affiliation(s)
- Marea J Blake
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996
| | - Brandon A Colon
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996
| | - Tessa R Calhoun
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996
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Francis AT, Shears MJ, Murphy SC, Fu D. Direct Quantification of Single Red Blood Cell Hemoglobin Concentration with Multiphoton Microscopy. Anal Chem 2020; 92:12235-12241. [PMID: 32786430 DOI: 10.1021/acs.analchem.0c01609] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Blood disorders, diseases, and infections often affect the shape, number, and content of red blood cells (RBCs) dramatically. To combat these pathologies, many therapies target RBCs and their contents directly. Mean corpuscular hemoglobin concentration (MCHC) is an important pathological metric in both identification and treatment. However, current methods for RBC analysis and MCHC quantification rely on bulk measurements. Single RBC measurements could provide necessary insight into the heterogeneity of RBC health and improve therapeutic efficacy. In this study, we present a novel multimodal multiphoton approach for quantifying hemoglobin concentration at single RBC resolution. We achieve this by collecting two images simultaneously that allows us to excite water with stimulated Raman scattering and hemoglobin with transient absorption. This multimodal imaging is enabled by a newly designed orthogonal modulation theme for dual-channel lock-in detection. By leveraging water as an internal standard, we quantify MCHC of healthy RBCs and RBCs infected with Plasmodium yoelii, a commonly studied rodent parasite model.
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Affiliation(s)
- Andrew T Francis
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Melanie J Shears
- Department of Laboratory Medicine and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, 750 Republican Street, Seattle, Washington 98109, United States
| | - Sean C Murphy
- Department of Laboratory Medicine and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, 750 Republican Street, Seattle, Washington 98109, United States
| | - Dan Fu
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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Colon BA, Hassan MR, Saleheen A, Baker CA, Calhoun TR. Total Internal Reflection Transient Absorption Microscopy: An Online Detection Method for Microfluidics. J Phys Chem A 2020; 124:4160-4170. [PMID: 32338897 DOI: 10.1021/acs.jpca.9b12046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Microreactors have garnered widespread attention for their tunability and precise control of synthetic parameters to efficiently produce target species. Despite associated advances, a lack of online detection and optimization methods has stalled the progression of microfluidic reactors. Here we employ and characterize a total internal reflection transient absorption microscopy (TIRTAM) instrument to image excited state dynamics on a continuous flow device. The experiments presented demonstrate the capability to discriminate between different chromophores as well as in differentiating the effects of local chemical environments that a chromophore experiences. This work presents the first such online transient absorption measurements and provides a new direction for the advancement and optimization of chemical reactions in microfluidic devices.
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Affiliation(s)
- Brandon A Colon
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Muhammad Redwan Hassan
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Amirus Saleheen
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Christopher A Baker
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Tessa R Calhoun
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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11
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Zhu Y, Cheng JX. Transient absorption microscopy: Technological innovations and applications in materials science and life science. J Chem Phys 2020; 152:020901. [PMID: 31941290 PMCID: PMC7195865 DOI: 10.1063/1.5129123] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/15/2019] [Indexed: 01/08/2023] Open
Abstract
Transient absorption (TA) spectroscopy has been extensively used in the study of excited state dynamics of various materials and molecules. The transition from TA spectroscopy to TA microscopy, which enables the space-resolved measurement of TA, is opening new investigations toward a more complete picture of excited state dynamics in functional materials, as well as the mapping of crucial biopigments for precision diagnosis. Here, we review the recent instrumental advancement that is pushing the limit of spatial resolution, detection sensitivity, and imaging speed. We further highlight the emerging application in materials science and life science.
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Affiliation(s)
- Yifan Zhu
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA
| | - Ji-Xin Cheng
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA
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12
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Hill AH, Munger E, Francis AT, Manifold B, Fu D. Frequency Modulation Stimulated Raman Scattering Microscopy through Polarization Encoding. J Phys Chem B 2019; 123:8397-8404. [PMID: 31532680 DOI: 10.1021/acs.jpcb.9b07075] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Stimulated Raman scattering (SRS) microscopy is a powerful method for imaging molecular distributions based on their intrinsic vibrational contrast. However, despite a growing list of biological applications, SRS is frequently hindered by a parasitic background signal which both overpowers the signal in low-signal applications and makes the extraction of quantitative information from images challenging. Frequency modulation (FM) has been used to suppress this parasitic background. However, many FM-SRS methods require either the acquisition of multiple images or the addition of multiple optomechanical components and an extensive realignment procedure. Herein, we report a new procedure for alignment-free FM-SRS utilizing polarization encoding. We demonstrate the efficacy of this approach, along with parabolic amplification of the Stokes pulse, at removing parasitic background signals in SRS microscopy applications. We further highlight how this technique can be used to suppress Raman signals from major molecular species to unveil spectral signatures from nucleic acids in both murine brain tissue and whole blood. Due to its ease of use and demonstrated experimental capabilities, we expect this technique to see broad use in the SRS microscopy community.
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Affiliation(s)
- Andrew H Hill
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
| | - Eleanor Munger
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
| | - Andrew T Francis
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
| | - Bryce Manifold
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
| | - Dan Fu
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , United States
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