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Pham DL, Gillette AA, Riendeau J, Wiech K, Guzman EC, Datta R, Skala MC. Perspectives on label-free microscopy of heterogeneous and dynamic biological systems. JOURNAL OF BIOMEDICAL OPTICS 2025; 29:S22702. [PMID: 38434231 PMCID: PMC10903072 DOI: 10.1117/1.jbo.29.s2.s22702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/22/2023] [Accepted: 12/14/2023] [Indexed: 03/05/2024]
Abstract
Significance Advancements in label-free microscopy could provide real-time, non-invasive imaging with unique sources of contrast and automated standardized analysis to characterize heterogeneous and dynamic biological processes. These tools would overcome challenges with widely used methods that are destructive (e.g., histology, flow cytometry) or lack cellular resolution (e.g., plate-based assays, whole animal bioluminescence imaging). Aim This perspective aims to (1) justify the need for label-free microscopy to track heterogeneous cellular functions over time and space within unperturbed systems and (2) recommend improvements regarding instrumentation, image analysis, and image interpretation to address these needs. Approach Three key research areas (cancer research, autoimmune disease, and tissue and cell engineering) are considered to support the need for label-free microscopy to characterize heterogeneity and dynamics within biological systems. Based on the strengths (e.g., multiple sources of molecular contrast, non-invasive monitoring) and weaknesses (e.g., imaging depth, image interpretation) of several label-free microscopy modalities, improvements for future imaging systems are recommended. Conclusion Improvements in instrumentation including strategies that increase resolution and imaging speed, standardization and centralization of image analysis tools, and robust data validation and interpretation will expand the applications of label-free microscopy to study heterogeneous and dynamic biological systems.
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Affiliation(s)
- Dan L. Pham
- University of Wisconsin—Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | | | | | - Kasia Wiech
- University of Wisconsin—Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | | | - Rupsa Datta
- Morgridge Institute for Research, Madison, Wisconsin, United States
| | - Melissa C. Skala
- University of Wisconsin—Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
- Morgridge Institute for Research, Madison, Wisconsin, United States
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2
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Hu L, Morganti S, Nguyen U, Benavides OR, Walsh AJ. Label-free optical imaging of cell function and collagen structure for cell-based therapies. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2023; 25:100433. [PMID: 36642995 PMCID: PMC9836225 DOI: 10.1016/j.cobme.2022.100433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cell-based therapies harness functional cells or tissues to mediate healing and treat disease. Assessment of cellular therapeutics requires methods that are non-destructive to ensure therapies remain viable and uncontaminated for use in patients. Optical imaging of endogenous collagen, by second-harmonic generation, and the metabolic coenzymes NADH and FAD, by autofluorescence microscopy, provides tissue structure and cellular information. Here, we review applications of label-free nonlinear optical imaging of cellular metabolism and collagen second-harmonic generation for assessing cell-based therapies. Additionally, we discuss the potential of label-free imaging for quality control of cell-based therapies, as well as the current limitations and potential future directions of label-free imaging technologies.
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3
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Zhou X, Haudenschild AK, Li C, Marcu L. Multimodal fluorescence lifetime imaging and optical coherence tomography for longitudinal monitoring of tissue-engineered cartilage maturation in a preclinical implantation model. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:026003. [PMID: 36818585 PMCID: PMC9932524 DOI: 10.1117/1.jbo.28.2.026003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Significance Cartilage tissue engineering is a promising strategy for effective curative therapies for treatment of osteoarthritis. However, tissue engineers depend predominantly on time-consuming, expensive, and destructive techniques as quality control to monitor the maturation of engineered cartilage. This practice can be impractical for large-scale biomanufacturing and prevents spatial and temporal monitoring of tissue growth, which is critical for the fabrication of clinically relevant-sized cartilage constructs. Nondestructive multimodal imaging techniques combining fluorescence lifetime imaging (FLIm) and optical coherence tomography (OCT) hold great potential to address this challenge. Aim The feasibility of using multimodal FLIm-OCT for nondestructive, spatial, and temporal monitoring of self-assembled cartilage tissue maturation in a preclinical mouse model is investigated. Approach Self-assembled cartilage constructs were developed for 4 weeks in vitro followed by 4 weeks of in vivo maturation in nude mice. Sterile and nondestructive in situ multispectral FLIm and OCT imaging were carried out at multiple time points ( t = 2 , 4, and 8 weeks) during tissue development. FLIm and 3D volumetric OCT images were reconstructed and used for the analysis of tissue biochemical homogeneity, morphology, and structural integrity. A biochemical homogeneity index was computed to characterize nonhomogeneous tissue growth at different time points. OCT images were validated against histology. Results FLIm detects heterogenous extracellular matrix (ECM) growth of tissue-engineered cartilage. The outer edge of the tissue construct exhibited longer fluorescence lifetime in 375 to 410 and 450 to 485 nm spectral channels, indicating increase in collagen content. Significant ( p < 0.05 ) decrease of construct homogeneity index was observed between t = 2 weeks and t = 4 weeks. Both FLIm and OCT images revealed defects (voids) at the center of the tissue construct during in vitro culture ( t = 2 and 4 weeks). Cyst formation during in vivo culture was detected by OCT and confirmed with histology. Conclusions The ability of multimodal FLIm-OCT to nondestructively monitor the heterogenous growth of engineered tissue constructs in situ is demonstrated. Spatial and temporal variation of construct ECM component was detected by FLIm. OCT reveals structural defects (voids and cysts). This multimodal approach has great potential to replace costly destructive tests in the manufacturing of tissue-engineered medical products, facilitating their clinical translation.
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Affiliation(s)
- Xiangnan Zhou
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
| | - Anne K. Haudenschild
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
| | - Cai Li
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
| | - Laura Marcu
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
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4
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Non-destructive, continuous monitoring of biochemical, mechanical, and structural maturation in engineered tissue. Sci Rep 2022; 12:16227. [PMID: 36171228 PMCID: PMC9519952 DOI: 10.1038/s41598-022-18702-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 08/17/2022] [Indexed: 11/08/2022] Open
Abstract
Regulatory guidelines for tissue engineered products require stringent characterization during production and necessitate the development of novel, non-destructive methods to quantify key functional parameters for clinical translation. Traditional assessments of engineered tissues are destructive, expensive, and time consuming. Here, we introduce a non-destructive, inexpensive, and rapid sampling and analysis system that can continuously monitor the mechanical, biochemical, and structural properties of a single sample over extended periods of time. The label-free system combines the imaging modalities of fluorescent lifetime imaging and ultrasound backscatter microscopy through a fiber-based interface for sterile monitoring of tissue quality. We tested the multimodal system using tissue engineered articular cartilage as an experimental model. We identified strong correlations between optical and destructive testing. Combining FLIm and UBM results, we created a novel statistical model of tissue homogeneity that can be applied to tissue engineered constructs prior to implantation. Continuous monitoring of engineered tissues with this non-destructive system has the potential for in-process monitoring of tissue engineered products, reducing costs and improving quality controls in research, manufacturing, and clinical applications.
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5
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Yakimov BP, Vlasova II, Efremov YM, Maksimov EG, Shirshin EA, Kagan VE, Timashev PS. Detection of HOCl-driven degradation of the pericardium scaffolds by label-free multiphoton fluorescence lifetime imaging. Sci Rep 2022; 12:10329. [PMID: 35725581 PMCID: PMC9209456 DOI: 10.1038/s41598-022-14138-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 05/17/2022] [Indexed: 11/24/2022] Open
Abstract
Artificial biomaterials can significantly increase the rate of tissue regeneration. However, implantation of scaffolds leads not only to accelerated tissue healing but also to an immune response of the organism, which results in the degradation of the biomaterial. The synergy of the immune response and scaffold degradation processes largely determines the efficiency of tissue regeneration. Still, methods suitable for fast, accurate and non-invasive characterization of the degradation degree of biomaterial are highly demandable. Here we show the possibility of monitoring the degradation of decellularized bovine pericardium scaffolds under conditions mimicking the immune response and oxidation processes using multiphoton tomography combined with fluorescence lifetime imaging (MPT-FLIM). We found that the fluorescence lifetimes of genipin-induced cross-links in collagen and oxidation products of collagen are prominent markers of oxidative degradation of scaffolds. This was verified in model experiments, where the oxidation was induced with hypochlorous acid or by exposure to activated neutrophils. The fluorescence decay parameters also correlated with the changes of micromechanical properties of the scaffolds as assessed using atomic force microscopy (AFM). Our results suggest that FLIM can be used for quantitative assessments of the properties and degradation of the scaffolds essential for the wound healing processes in vivo.
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Affiliation(s)
- B P Yakimov
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia, 119048.,Faculty of Physics, M.V. Lomonosov Moscow State University, 1-2 Leninskie Gory, Moscow, Russia, 119991
| | - I I Vlasova
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia, 119048.,Department of Advanced Biomaterials, Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia, 119048
| | - Y M Efremov
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia, 119048.,Department of Advanced Biomaterials, Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia, 119048
| | - E G Maksimov
- Faculty of Biology, M.V. Lomonosov Moscow State University, 1-12 Leninskie Gory, Moscow, Russia, 119991
| | - E A Shirshin
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia, 119048. .,Faculty of Physics, M.V. Lomonosov Moscow State University, 1-2 Leninskie Gory, Moscow, Russia, 119991.
| | - V E Kagan
- Department of Advanced Biomaterials, Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia, 119048.,Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - P S Timashev
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia, 119048. .,Department of Advanced Biomaterials, Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia, 119048. .,Faculty of Chemistry, M.V. Lomonosov Moscow State University, 1-3 Leninskie Gory, Moscow, Russia, 119991.
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6
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Poole JJA, Mostaço-Guidolin LB. Optical Microscopy and the Extracellular Matrix Structure: A Review. Cells 2021; 10:1760. [PMID: 34359929 PMCID: PMC8308089 DOI: 10.3390/cells10071760] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 02/07/2023] Open
Abstract
Biological tissues are not uniquely composed of cells. A substantial part of their volume is extracellular space, which is primarily filled by an intricate network of macromolecules constituting the extracellular matrix (ECM). The ECM serves as the scaffolding for tissues and organs throughout the body, playing an essential role in their structural and functional integrity. Understanding the intimate interaction between the cells and their structural microenvironment is central to our understanding of the factors driving the formation of normal versus remodelled tissue, including the processes involved in chronic fibrotic diseases. The visualization of the ECM is a key factor to track such changes successfully. This review is focused on presenting several optical imaging microscopy modalities used to characterize different ECM components. In this review, we describe and provide examples of applications of a vast gamut of microscopy techniques, such as widefield fluorescence, total internal reflection fluorescence, laser scanning confocal microscopy, multipoint/slit confocal microscopy, two-photon excited fluorescence (TPEF), second and third harmonic generation (SHG, THG), coherent anti-Stokes Raman scattering (CARS), fluorescence lifetime imaging microscopy (FLIM), structured illumination microscopy (SIM), stimulated emission depletion microscopy (STED), ground-state depletion microscopy (GSD), and photoactivated localization microscopy (PALM/fPALM), as well as their main advantages, limitations.
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Affiliation(s)
- Joshua J A Poole
- Department of Systems and Computer Engineering, Faculty of Engineering and Design, Carleton University 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - Leila B Mostaço-Guidolin
- Department of Systems and Computer Engineering, Faculty of Engineering and Design, Carleton University 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
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7
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Zhou X, Bec J, Yankelevich D, Marcu L. Multispectral fluorescence lifetime imaging device with a silicon avalanche photodetector. OPTICS EXPRESS 2021; 29:20105-20120. [PMID: 34266107 PMCID: PMC8237936 DOI: 10.1364/oe.425632] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 05/08/2023]
Abstract
We report the design, development, and characterization of a novel multi-spectral fluorescence lifetime measurement device incorporating solid-state detectors and automated gain control. For every excitation pulse (∼1 µJ, 600 ps), this device records complete fluorescence decay from multiple spectral channels simultaneously within microseconds, using a dedicated UV enhanced avalanche photodetector and analog to digital convert (2.5 GS/s) in each channel. Fast (<2 ms) channel-wise dynamic range adjustment maximizes the signal-to-noise ratio. Fluorophores with known lifetime ranging from 0.5-6.0 ns were used to demonstrate the device accuracy. Current results show the clear benefits of this device compared to existing devices employing microchannel-plate photomultiplier tubes. This is demonstrated by 5-fold reduction of lifetime measurement variability in identical conditions, independent gain adjustment in each spectral band, and 4-times faster imaging speed. The use of solid-state detectors will also facilitate future improved performance and miniaturization of the instrument.
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Affiliation(s)
- Xiangnan Zhou
- Department of Biomedical Engineering, University of California, 451 Health Sciences Drive, Davis, California 95616, USA
| | - Julien Bec
- Department of Biomedical Engineering, University of California, 451 Health Sciences Drive, Davis, California 95616, USA
| | - Diego Yankelevich
- Department of Electrical and Computer Engineering, University of California, 3101 Kemper Hall, Davis, California 95616, USA
| | - Laura Marcu
- Department of Biomedical Engineering, University of California, 451 Health Sciences Drive, Davis, California 95616, USA
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8
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Bielajew BJ, Hu JC, Athanasiou KA. Collagen: quantification, biomechanics, and role of minor subtypes in cartilage. NATURE REVIEWS. MATERIALS 2020; 5:730-747. [PMID: 33996147 PMCID: PMC8114887 DOI: 10.1038/s41578-020-0213-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/28/2020] [Indexed: 05/02/2023]
Abstract
Collagen is a ubiquitous biomaterial in vertebrate animals. Although each of its 28 subtypes contributes to the functions of many different tissues in the body, most studies on collagen or collagenous tissues have focussed on only one or two subtypes. With recent developments in analytical chemistry, especially mass spectrometry, significant advances have been made toward quantifying the different collagen subtypes in various tissues; however, high-throughput and low-cost methods for collagen subtype quantification do not yet exist. In this Review, we introduce the roles of collagen subtypes and crosslinks, and describe modern assays that enable a deep understanding of tissue physiology and disease states. Using cartilage as a model tissue, we describe the roles of major and minor collagen subtypes in detail; discuss known and unknown structure-function relationships; and show how tissue engineers may harness the functional characteristics of collagen to engineer robust neotissues.
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Affiliation(s)
- Benjamin J. Bielajew
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617, USA
| | - Jerry C. Hu
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617, USA
| | - Kyriacos A. Athanasiou
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617, USA
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9
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Vazquez-Portalatin N, Alfonso-Garcia A, Liu JC, Marcu L, Panitch A. Physical, Biomechanical, and Optical Characterization of Collagen and Elastin Blend Hydrogels. Ann Biomed Eng 2020; 48:2924-2935. [PMID: 32929559 DOI: 10.1007/s10439-020-02605-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/02/2020] [Indexed: 12/13/2022]
Abstract
Collagen and elastin proteins are major components of the extracellular matrix of many organs. The presence of collagen and elastin networks, and their associated properties, in different tissues have led scientists to study collagen and elastin composites for use in tissue engineering. In this study, we characterized physical, biochemical, and optical properties of gels composed of collagen and elastin blends. We demonstrated that the addition of varying amounts of elastin to the constructs alters collagen fibrillogenesis, D-banding pattern length, and storage modulus. However, the addition of elastin does not affect collagen fibril diameter. We also evaluated the autofluorescence properties of the different collagen and elastin blends with fluorescence lifetime imaging (FLIm). Autofluorescence emission showed a red shift with the addition of elastin to the hydrogels. The fluorescence lifetime values of the gels increased with the addition of elastin and were strongly correlated with the storage moduli measurements. These results suggest that FLIm can be used to monitor the gels' mechanical properties nondestructively. These collagen and elastin constructs, along with the FLIm capabilities, can be used to develop and study collagen and elastin composites for tissue engineering and regenerative medicine.
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Affiliation(s)
- Nelda Vazquez-Portalatin
- Biomedical Engineering Department, University of California, Davis, 451 Health Sciences Dr, Davis, CA, 95616, USA.,Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Dr, West Lafayette, IN, 47907, USA
| | - Alba Alfonso-Garcia
- Biomedical Engineering Department, University of California, Davis, 451 Health Sciences Dr, Davis, CA, 95616, USA
| | - Julie C Liu
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Dr, West Lafayette, IN, 47907, USA.,Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Dr, West Lafayette, IN, 47907, USA
| | - Laura Marcu
- Biomedical Engineering Department, University of California, Davis, 451 Health Sciences Dr, Davis, CA, 95616, USA
| | - Alyssa Panitch
- Biomedical Engineering Department, University of California, Davis, 451 Health Sciences Dr, Davis, CA, 95616, USA. .,Department of Surgery, University of California, Davis, 2335 Stockton Boulevard, Sacramento, CA, 95817, USA.
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10
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Shaik TA, Alfonso-Garcia A, Richter M, Korinth F, Krafft C, Marcu L, Popp J. FLIm and Raman Spectroscopy for Investigating Biochemical Changes of Bovine Pericardium upon Genipin Cross-Linking. Molecules 2020; 25:E3857. [PMID: 32854230 PMCID: PMC7503846 DOI: 10.3390/molecules25173857] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 12/11/2022] Open
Abstract
Biomaterials used in tissue engineering and regenerative medicine applications benefit from longitudinal monitoring in a non-destructive manner. Label-free imaging based on fluorescence lifetime imaging (FLIm) and Raman spectroscopy were used to monitor the degree of genipin (GE) cross-linking of antigen-removed bovine pericardium (ARBP) at three incubation time points (0.5, 1.0, and 2.5 h). Fluorescence lifetime decreased and the emission spectrum redshifted compared to that of uncross-linked ARBP. The Raman signature of GE-ARBP was resonance-enhanced due to the GE cross-linker that generated new Raman bands at 1165, 1326, 1350, 1380, 1402, 1470, 1506, 1535, 1574, 1630, 1728, and 1741 cm-1. These were validated through density functional theory calculations as cross-linker-specific bands. A multivariate multiple regression model was developed to enhance the biochemical specificity of FLIm parameters fluorescence intensity ratio (R2 = 0.92) and lifetime (R2 = 0.94)) with Raman spectral results. FLIm and Raman spectroscopy detected biochemical changes occurring in the collagenous tissue during the cross-linking process that were characterized by the formation of a blue pigment which affected the tissue fluorescence and scattering properties. In conclusion, FLIm parameters and Raman spectroscopy were used to monitor the degree of cross-linking non-destructively.
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Affiliation(s)
- Tanveer Ahmed Shaik
- Leibniz Institute of Photonic Technology Jena e.V., Albert-Einstein-Str. 9, 07745 Jena, Germany; (T.A.S.); (F.K.); (C.K.)
| | - Alba Alfonso-Garcia
- Biomedical Engineering Department, University of California Davis, Davis, CA 95616, USA;
| | - Martin Richter
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany;
| | - Florian Korinth
- Leibniz Institute of Photonic Technology Jena e.V., Albert-Einstein-Str. 9, 07745 Jena, Germany; (T.A.S.); (F.K.); (C.K.)
| | - Christoph Krafft
- Leibniz Institute of Photonic Technology Jena e.V., Albert-Einstein-Str. 9, 07745 Jena, Germany; (T.A.S.); (F.K.); (C.K.)
| | - Laura Marcu
- Biomedical Engineering Department, University of California Davis, Davis, CA 95616, USA;
| | - Jürgen Popp
- Leibniz Institute of Photonic Technology Jena e.V., Albert-Einstein-Str. 9, 07745 Jena, Germany; (T.A.S.); (F.K.); (C.K.)
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany;
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11
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Shaik TA, Alfonso-García A, Zhou X, Arnold KM, Haudenschild AK, Krafft C, Griffiths LG, Popp J, Marcu L. FLIm-Guided Raman Imaging to Study Cross-Linking and Calcification of Bovine Pericardium. Anal Chem 2020; 92:10659-10667. [PMID: 32598134 PMCID: PMC7539574 DOI: 10.1021/acs.analchem.0c01772] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Bovine pericardium (BP) is a vascular biomaterial used in cardiovascular surgery that is typically cross-linked for masking antigenicity and enhance stability. There is a need for biochemical evaluation of the tissue properties prior to implantation to ensure that quality and reliability standards are met. Here, engineered antigen removed BP (ARBP) that was cross-linked with 0.2% and 0.6% glutaraldehyde (GA), and further calcified in vitro to simulate graft calcifications upon implantation was characterized nondestructively using fluorescence lifetime imaging (FLIm) to identify regions of interest which were then assessed by Raman spectroscopy. We observed that the tissue fluorescence lifetime shortened, and that Raman bands at 856, 935, 1282, and 1682 cm-1 decreased, and at 1032 and 1627 cm-1 increased with increasing GA cross-linking. Independent classification analysis based on fluorescence lifetime and on Raman spectra discriminated between GA-ARBP and untreated ARBP with an accuracy of 91% and 66%, respectively. Pearson's correlation analysis showed a strong correlation between pyridinium cross-links measured with high-performance liquid chromatography and fluorescence lifetime measured at 380-400 nm (R = -0.76, p = 0.00094), as well as Raman bands at 856 cm-1 for hydroxy-proline (R = -0.68, p = 0.0056) and at 1032 cm-1 for hydroxy-pyridinium (R = 0.74, p = 0.0016). Calcified areas of GA cross-linked tissue showed characteristic hydroxyapatite (959 and 1038 cm-1) bands in the Raman spectrum and fluorescence lifetime shortened by 0.4 ns compared to uncalcified regions. FLIm-guided Raman imaging could rapidly identify degrees of cross-linking and detected calcified regions with high chemical specificity, an ability that can be used to monitor tissue engineering processes for applications in regenerative medicine.
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Affiliation(s)
- Tanveer Ahmed Shaik
- Leibniz Institute of Photonic Technology Jena e.V., Albert-Einstein-Strasse 9, 07745 Jena, Germany
| | - Alba Alfonso-García
- Department of Biomedical Engineering, University of California Davis, One Shields Avenue, Davis, California 95616, United States
| | - Xiangnan Zhou
- Department of Biomedical Engineering, University of California Davis, One Shields Avenue, Davis, California 95616, United States
| | - Katherine M Arnold
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905, United States
| | - Anne K Haudenschild
- Department of Biomedical Engineering, University of California Davis, One Shields Avenue, Davis, California 95616, United States
| | - Christoph Krafft
- Leibniz Institute of Photonic Technology Jena e.V., Albert-Einstein-Strasse 9, 07745 Jena, Germany
| | - Leigh G Griffiths
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905, United States
| | - Jürgen Popp
- Leibniz Institute of Photonic Technology Jena e.V., Albert-Einstein-Strasse 9, 07745 Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Laura Marcu
- Department of Biomedical Engineering, University of California Davis, One Shields Avenue, Davis, California 95616, United States
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