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Li J, Wang D, Pottenburgh J, Bower AJ, Asanad S, Lai EW, Simon C, Im L, Huryn LA, Tao Y, Tam J, Saeedi OJ. Visualization of erythrocyte stasis in the living human eye in health and disease. iScience 2023; 26:105755. [PMID: 36594026 PMCID: PMC9803835 DOI: 10.1016/j.isci.2022.105755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/25/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022] Open
Abstract
Blood cells trapped in stasis have been reported within the microcirculation, but their relevance to health and disease has not been established. In this study, we introduce an in vivo imaging approach that reveals the presence of a previously-unknown pool of erythrocytes in stasis, located within capillary segments of the CNS, and present in 100% of subjects imaged. These results provide a key insight that blood cells pause as they travel through the choroidal microvasculature, a vascular structure that boasts the highest blood flow of any tissue in the body. Demonstration of clinical utility using deep learning reveals that erythrocyte stasis is altered in glaucoma, indicating the possibility of more widespread changes in choroidal microvascular than previously realized. The ability to monitor the choroidal microvasculature at the single cell level may lead to novel strategies for tracking microvascular health in glaucoma, age-related macular degeneration, and other neurodegenerative diseases.
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Affiliation(s)
- Joanne Li
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Dongyi Wang
- Bioimaging and Machine Vision Laboratory, Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Jessica Pottenburgh
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrew J. Bower
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Samuel Asanad
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Eric W. Lai
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Caroline Simon
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Lily Im
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Laryssa A. Huryn
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yang Tao
- Bioimaging and Machine Vision Laboratory, Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Johnny Tam
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Osamah J. Saeedi
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
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2
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Zhang H, Zhu L, Gao DS, Liu Y, Zhang J, Yan M, Qian J, Xi W. Imaging the Deep Spinal Cord Microvascular Structure and Function with High-Speed NIR-II Fluorescence Microscopy. SMALL METHODS 2022; 6:e2200155. [PMID: 35599368 DOI: 10.1002/smtd.202200155] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/23/2022] [Indexed: 06/15/2023]
Abstract
The spinal cord (SC) is crucial for a myriad of somatosensory, autonomic signal processing, and transductions. Understanding the SC vascular structure and function thus plays an integral part in neuroscience and clinical research. However, the dense layers of myelinated ascending axons on the dorsal side inconveniently grant the SC tissue with high optical scattering property, which significantly hinders the imaging depth of the SC vasculature in vivo. Commonly used antiscattering techniques such as multiphoton fluorescence microscopy have low imaging speed and cannot capture the rapid vascular particle flow without significant motion blur. Here, advantage of the high penetration of near-infrared (NIR)-II fluorescence is taken to demonstrate a deep SC vascular structural image stack up to 350 µm, comparable to two-photon microscopy. Furthermore, the red blood cells are labelled with the clinically approved NIR dye indocyanine. The combination of a fast NIR camera and indocyanine green-red blood cells (RBCs) makes it possible to attain high-speed 100 frame-per-second NIR-II imaging to identify the corresponding changes in RBC velocity during the external hind leg stimulus. For the first time, it is established that the NIR-II region would be a promising spectral window for SC imaging. NIR-II fluorescence microscopy has excellent potential for clinical and basic science research on SC.
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Affiliation(s)
- Hequn Zhang
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), Department of Anesthesiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310020, China
- MOE Frontier Science Center for Brain Research and Brain Machine Integration, Zhejiang University, Hangzhou, 310058, China
| | - Liang Zhu
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), Department of Anesthesiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310020, China
- MOE Frontier Science Center for Brain Research and Brain Machine Integration, Zhejiang University, Hangzhou, 310058, China
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310027, China
| | - Dave Schwinn Gao
- Key Laboratory of The Diagnosis and Treatment of Severe Trauma and Burn of Zhejiang Province, Department of Anesthesiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Yin Liu
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), Department of Anesthesiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310020, China
- MOE Frontier Science Center for Brain Research and Brain Machine Integration, Zhejiang University, Hangzhou, 310058, China
| | - Jun Zhang
- Department of Spine Surgery, Zhejiang Provincial People's Hospital, Hangzhou Medical School People's Hospital, Shangtang Road 158th, Hangzhou, Zhejiang Province, 310014, China
| | - Min Yan
- Key Laboratory of The Diagnosis and Treatment of Severe Trauma and Burn of Zhejiang Province, Department of Anesthesiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Jun Qian
- State Key Laboratory of Modern Optical Instrumentations, Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Wang Xi
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT), Department of Anesthesiology, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310020, China
- MOE Frontier Science Center for Brain Research and Brain Machine Integration, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and instrument Science, Zhejiang University, Hangzhou, 310027, China
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3
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Tang JC, Lee CH, Lu T, Vankayala R, Hanley T, Azubuogu C, Li J, Nair MG, Jia W, Anvari B. Membrane Cholesterol Enrichment of Red Blood Cell-Derived Microparticles Results in Prolonged Circulation. ACS APPLIED BIO MATERIALS 2022; 5:650-660. [PMID: 35006664 PMCID: PMC9924066 DOI: 10.1021/acsabm.1c01104] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Particles fabricated from red blood cells (RBCs) can serve as vehicles for delivery of various biomedical cargos. Flipping of phosphatidylserine (PS) from the inner to the outer membrane leaflet normally occurs during the fabrication of such particles. PS externalization is a signal for phagocytic removal of the particles from circulation. Herein, we demonstrate that membrane cholesterol enrichment can mitigate the outward display of PS on microparticles engineered from RBCs. Our in-vitro results show that the phagocytic uptake of cholesterol-enriched particles by murine macrophages takes place at a lowered rate, resulting in reduced uptake as compared to RBC-derived particles without cholesterol enrichment. When administered via tail-vein injection into healthy mice, the percent of injected dose (ID) per gram of extracted blood for cholesterol-enriched particles was ∼1.5 and 1.8 times higher than the particles without cholesterol enrichment at 4 and 24 h, respectively. At 24 h, ∼43% ID/g of the particles without cholesterol enrichment was eliminated or metabolized while ∼94% ID/g of the cholesterol-enriched particles were still retained in the body. These results indicate that membrane cholesterol enrichment is an effective method to reduce PS externalization on the surface of RBC-derived particles and increase their longevity in circulation.
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Affiliation(s)
- Jack C. Tang
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States; Present Address: University of Southern California, Los Angeles, California 90033, United States
| | - Chi-Hua Lee
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Thompson Lu
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States
| | - Raviraj Vankayala
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States; Present Address: Indian Institute of Technology Jodhpur, Karwar, Jodhpur, Rajasthan 342037, India
| | - Taylor Hanley
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States
| | - Chiemerie Azubuogu
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92023, United States
| | - Jiang Li
- Division of Biomedical Sciences, University of California, Riverside, Riverside, California 92521, United States
| | - Meera G. Nair
- Division of Biomedical Sciences, University of California, Riverside, Riverside, California 92521, United States
| | - Wangcun Jia
- Beckman Laser Institute & Medical Clinic, University of California, Irvine, Irvine, California 92617, United States
| | - Bahman Anvari
- Department of Bioengineering and Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
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4
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Marino MJ, Gehlbach PL, Rege A, Jiramongkolchai K. Current and novel multi-imaging modalities to assess retinal oxygenation and blood flow. Eye (Lond) 2021; 35:2962-2972. [PMID: 34117399 PMCID: PMC8526664 DOI: 10.1038/s41433-021-01570-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 01/28/2021] [Accepted: 04/20/2021] [Indexed: 02/05/2023] Open
Abstract
Retinal ischemia characterizes the underlying pathology in a multitude of retinal diseases that can ultimately lead to vision loss. A variety of novel imaging modalities have been developed to characterize retinal ischemia by measuring retinal oxygenation and blood flow in-vivo. These technologies offer valuable insight into the earliest pathophysiologic changes within the retina and provide physicians and researchers with new diagnostic and monitoring capabilities. Future retinal imaging technologies with the capability to provide affordable, noninvasive, and comprehensive data on oxygen saturation, vasculature, and blood flow mechanics are needed. This review will highlight current and future trends in multimodal imaging to assess retinal blood flow and oxygenation.
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Affiliation(s)
- Michael J. Marino
- grid.415233.20000 0004 0444 3298Department of Medicine, MedStar Union Memorial Hospital, Baltimore, MD USA
| | - Peter L. Gehlbach
- grid.21107.350000 0001 2171 9311Retina Division, The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Abhishek Rege
- grid.505446.6Vasoptic Medical, Inc., Baltimore, MD USA
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5
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Hanley T, Vankayala R, Lee CH, Tang JC, Burns JM, Anvari B. Phototheranostics Using Erythrocyte-Based Particles. Biomolecules 2021; 11:729. [PMID: 34068081 PMCID: PMC8152750 DOI: 10.3390/biom11050729] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 02/06/2023] Open
Abstract
There has been a recent increase in the development of delivery systems based on red blood cells (RBCs) for light-mediated imaging and therapeutic applications. These constructs are able to take advantage of the immune evasion properties of the RBC, while the addition of an optical cargo allows the particles to be activated by light for a number of promising applications. Here, we review some of the common fabrication methods to engineer these constructs. We also present some of the current light-based applications with potential for clinical translation, and offer some insight into future directions in this exciting field.
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Affiliation(s)
- Taylor Hanley
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; (T.H.); (R.V.); (J.C.T.); (J.M.B.)
| | - Raviraj Vankayala
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; (T.H.); (R.V.); (J.C.T.); (J.M.B.)
- Radoptics, Limited Liability Company, 1002 Health Sciences Road, East, Suite P214, Irvine, CA 92612, USA
| | - Chi-Hua Lee
- Department of Biochemistry, University of California, Riverside, CA 92521, USA;
| | - Jack C. Tang
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; (T.H.); (R.V.); (J.C.T.); (J.M.B.)
| | - Joshua M. Burns
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; (T.H.); (R.V.); (J.C.T.); (J.M.B.)
| | - Bahman Anvari
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; (T.H.); (R.V.); (J.C.T.); (J.M.B.)
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6
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Cho KA, Rege A, Jing Y, Chaurasia A, Guruprasad A, Arthur E, Cabrera DeBuc D. Portable, non-invasive video imaging of retinal blood flow dynamics. Sci Rep 2020; 10:20236. [PMID: 33214571 PMCID: PMC7677377 DOI: 10.1038/s41598-020-76407-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 07/27/2020] [Indexed: 02/04/2023] Open
Abstract
Retinal blood flow (RBF) information has the potential to offer insight into ophthalmic health and disease that is complementary to traditional anatomical biomarkers as well as to retinal perfusion information provided by fluorescence or optical coherence tomography angiography (OCT-A). The present study was performed to test the functional attributes and performance of the XyCAM RI, a non-invasive imager that obtains and assesses RBF information. The XyCAM RI was installed and used in two different settings to obtain video recordings of the blood flow in the optic nerve head region in eyes of healthy subjects. The mean blood flow velocity index (BFVi) in the optic disc and in each of multiple arterial and venous segments was obtained and shown to reveal a temporal waveform with a peak and trough that correlates with a cardiac cycle as revealed by a reference pulse oximeter (correlation between respective peak-to-peak distances was 0.977). The intra-session repeatability of the XyCAM RI was high with a coefficient of variation (CV) of 1.84 ± 1.13% across both sites. Artery-vein comparisons were made by estimating, in a pair of adjacent arterial and venous segments, various temporal waveform metrics such as pulsatility index, percent time in systole and diastole, and change in vascular blood volume over a cardiac cycle. All arterial metrics were shown to have significant differences with venous metrics (p < 0.001). The XyCAM RI, therefore, by obtaining repeatable blood flow measurements with high temporal resolution, permits the differential assessment of arterial and venous blood flow patterns in the retina that may facilitate research into disease pathophysiology and biomarker development for diagnostics.
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Affiliation(s)
| | | | - Yici Jing
- Vasoptic Medical, Inc., Baltimore, MD, USA
| | | | | | - Edmund Arthur
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Delia Cabrera DeBuc
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 N.W. 10th Avenue, Room 509, Miami, FL, 33136, USA.
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7
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Asanad S, Mohammed I, Sadun AA, Saeedi OJ. OCTA in neurodegenerative optic neuropathies: emerging biomarkers at the eye-brain interface. Ther Adv Ophthalmol 2020; 12:2515841420950508. [PMID: 32923939 PMCID: PMC7457690 DOI: 10.1177/2515841420950508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/13/2020] [Indexed: 12/22/2022] Open
Abstract
OCTA imaging in optic neuropathies.
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Affiliation(s)
- Samuel Asanad
- Department of Ophthalmology and Visual Sciences, University of Maryland Eye Associates, University of Maryland Medical Center and University of Maryland School of Medicine, 419 W. Redwood St., Baltimore, MD 21201, USA
| | - Isa Mohammed
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alfredo A Sadun
- Doheny Eye Center, Los Angeles, CA, USA; Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Osamah J Saeedi
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
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8
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Measurement of Retinal Microvascular Blood Velocity Using Erythrocyte Mediated Velocimetry. Sci Rep 2019; 9:20178. [PMID: 31882799 PMCID: PMC6934793 DOI: 10.1038/s41598-019-56239-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 12/07/2019] [Indexed: 01/08/2023] Open
Abstract
Changes in retinal blood flow may be involved in the pathogenesis of glaucoma and other ocular diseases. Erythrocyte mediated velocimetry (EMV) is a novel technique where indocyanine green (ICG) dye is sequestered in erythrocyte ghosts and autologously re-injected to allow direct visualization of erythrocytes for in vivo measurement of speed. The purpose of this study is to determine the mean erythrocyte speed in the retinal microvasculature, as well as the intravisit and intervisit variability of EMV. Data from 23 EMV sessions from control, glaucoma suspect, and glaucoma patients were included in this study. In arteries with an average diameter of 43.11 µm ± 6.62 µm, the mean speed was 7.17 mm/s ± 2.35 mm/s. In veins with an average diameter of 45.87 µm ± 12.04 µm, the mean speed was 6.05 mm/s ± 1.96 mm/s. Intravisit variability, as measured by the mean coefficient of variation, was 3.57% (range 0.44-9.68%). Intervisit variability was 4.85% (range 0.15-8.43%). EMV may represent reliable method for determination of retinal blood speed, potentially allowing insights into the effects of pharmacologic agents or pathogenesis of ocular diseases.
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Wang D, Haytham A, Mayo L, Tao Y, Saeedi O. Automated retinal microvascular velocimetry based on erythrocyte mediated angiography. BIOMEDICAL OPTICS EXPRESS 2019; 10:3681-3697. [PMID: 31360609 PMCID: PMC6640827 DOI: 10.1364/boe.10.003681] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/13/2019] [Accepted: 06/17/2019] [Indexed: 05/13/2023]
Abstract
Retinal blood flow is an emerging biomarker in ocular and systemic disease. Erythrocyte mediated angiography (EMA) is a novel technique that provides an easily interpretable blood flow velocity quantification by directly tracing individual moving erythrocyte ghosts over time in vivo, imaged using a scanning laser ophthalmoscope (Heidelberg Retina Angiograph platform). This tracking procedure, however, requires time-consuming manual analysis to determine blood flow. To overcome this current bottleneck, we developed an objective and automated velocimetry approach, EMA - Automated Velocimetry (EMA-AV), which is based on a modified sequential Monte Carlo method. The intra-class correlation coefficient (ICC) between trained human graders and EMA-AV is 0.98 for mean vessel velocity estimation and 0.92 for frame by frame erythrocyte velocity estimation. This study proves EMA-AV is a reliable tool for quantification of retinal microvascular velocity and flow and establishes EMA-AV as a reliable and interpretable tool for quantifying retinal microvascular velocity.
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Affiliation(s)
- Dongyi Wang
- Bio-Imaging and Machine Vision Lab, Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742,
USA
| | - Ayman Haytham
- Aureus University School of Medicine, Wayaca 31C, Oranjestad,
Aruba
| | - Lakyn Mayo
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, 419 W Redwood Street, Suite 470, Baltimore, MD 21201,
USA
| | - Yang Tao
- Bio-Imaging and Machine Vision Lab, Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742,
USA
| | - Osamah Saeedi
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, 419 W Redwood Street, Suite 470, Baltimore, MD 21201,
USA
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10
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Tang JC, Partono A, Anvari B. Near-Infrared-Fluorescent Erythrocyte-Mimicking Particles: Physical and Optical Characteristics. IEEE Trans Biomed Eng 2019; 66:1034-1044. [PMID: 30130175 PMCID: PMC6382600 DOI: 10.1109/tbme.2018.2866368] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Exogenous fluorescent materials activated by near-infrared (NIR) light can offer deep optical imaging with subcellular resolution, and enhanced image contrast. We have engineered NIR particles by doping hemoglobin-depleted erythrocyte ghosts (EGs) with indocyanine green (ICG). We refer to these optical particles as NIR erythrocyte-mimicking transducers (NETs). A particular feature of NETs is that their diameters can be tuned from micrometer to nanometer scale, thereby, providing a capability for broad NIR biomedical imaging applications. Herein, we investigate the effects of ICG concentration on key material properties of micrometer-sized NETs, and nanometer-sized NETs fabricated by either sonication or mechanical extrusion of EGs. The zeta potentials of NETs do not vary significantly with ICG concentration, suggesting that ICG is encapsulated within NETs regardless of particle size or ICG concentration. Loading efficiency of ICG into the NETs monotonically decreases with increasing values of ICG concentration. Based on quantitative analyses of the fluorescence emission spectra of the NETs, we determine that 20 μM ICG utilized during fabrication of NETs presents an optimal concentration that maximizes the integrated fluorescence emission for micrometer- and nanometer-sized NETs. Encapsulation of the ICG in these constructs also enhances the fluorescence stability and quantum yield of ICG. These results guide the engineering of NETs with maximal NIR emission for imaging applications such as fluorescence-guided tumor resection and real-time angiography.
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