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Yanez CO, Morales AR, Yue X, Urakami T, Komatsu M, Järvinen TAH, Belfield KD. Deep vascular imaging in wounds by two-photon fluorescence microscopy. PLoS One 2013; 8:e67559. [PMID: 23844028 PMCID: PMC3699647 DOI: 10.1371/journal.pone.0067559] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 05/20/2013] [Indexed: 01/22/2023] Open
Abstract
Deep imaging within tissue (over 300 μm) at micrometer resolution has become possible with the advent of two-photon fluorescence microscopy (2PFM). The advantages of 2PFM have been used to interrogate endogenous and exogenous fluorophores in the skin. Herein, we employed the integrin (cell-adhesion proteins expressed by invading angiogenic blood vessels) targeting characteristics of a two-photon absorbing fluorescent probe to image new vasculature and fibroblasts up to ≈ 1600 μm within wound (neodermis)/granulation tissue in lesions made on the skin of mice. Reconstruction revealed three dimensional (3D) architecture of the vascular plexus forming at the regenerating wound tissue and the presence of a fibroblast bed surrounding the capillaries. Biologically crucial events, such as angiogenesis for wound healing, may be illustrated and analyzed in 3D on the whole organ level, providing novel tools for biomedical applications.
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Affiliation(s)
- Ciceron O. Yanez
- Department of Chemistry, University of Central Florida, Orlando, Florida, United States of America
| | - Alma R. Morales
- Department of Chemistry, University of Central Florida, Orlando, Florida, United States of America
| | - Xiling Yue
- Department of Chemistry, University of Central Florida, Orlando, Florida, United States of America
| | - Takeo Urakami
- Sanford-Burnham Medical Research Institute at Lake Nona, Orlando, Florida, United States of America
| | - Masanobu Komatsu
- Sanford-Burnham Medical Research Institute at Lake Nona, Orlando, Florida, United States of America
| | - Tero A. H. Järvinen
- Department of Orthopaedic Surgery, Tampere City Hospital and Medical School, University of Tampere, Tampere, Finland
| | - Kevin D. Belfield
- Department of Chemistry, University of Central Florida, Orlando, Florida, United States of America
- The College of Optics and Photonics, University of Central Florida, Orlando, Florida, United States of America
- * E-mail:
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Non-invasive depth profile imaging of the stratum corneum using confocal Raman microscopy: first insights into the method. Eur J Pharm Sci 2013; 50:601-8. [PMID: 23764946 DOI: 10.1016/j.ejps.2013.05.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/21/2013] [Accepted: 05/31/2013] [Indexed: 11/21/2022]
Abstract
The stratum corneum is a strong barrier that must be overcome to achieve successful transdermal delivery of a pharmaceutical agent. Many strategies have been developed to enhance the permeation through this barrier. Traditionally, drug penetration through the stratum corneum is evaluated by employing tape-stripping protocols and measuring the content of the analyte. Although effective, this method cannot provide a detailed information regarding the penetration pathways. To address this issue various microscopic techniques have been employed. Raman microscopy offers the advantage of label free imaging and provides spectral information regarding the chemical integrity of the drug as well as the tissue. In this paper we present a relatively simple method to obtain XZ-Raman profiles of human stratum corneum using confocal Raman microscopy on intact full thickness skin biopsies. The spectral datasets were analysed using a spectral unmixing algorithm. The spectral information obtained, highlights the different components of the tissue and the presence of drug. We present Raman images of untreated skin and diffusion patterns for deuterated water and beta-carotene after Franz-cell diffusion experiment.
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Stefania S, Simona S, Paola A, Luisa B, Stefania B, Jennifer C, Chiara F, Paul F, Stefania G, Karsten K, Cristina M, Clifford T, Christopher D. High-resolution multiphoton tomography and fluorescence lifetime imaging of UVB-induced cellular damage on cultured fibroblasts producing fibres. Skin Res Technol 2013; 19:251-7. [PMID: 23590582 DOI: 10.1111/srt.12034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2012] [Indexed: 12/20/2022]
Abstract
BACKGROUND Multiphoton tomography (MPT) is suitable to perform both ex vivo and in vivo investigations of living skin and cell cultures with submicron resolution. Fluorescence lifetime imaging (FLIM) generates image contrast between different states of tissue characterized by various fluorescence decay rates. Our purpose was to combine MPT and FLIM to evaluate fibroblasts and collagen fibres produced in vitro. METHODS Fibroblast cultures, 2-4 days old, at a subconfluent stage, were evaluated before and after irradiation with a single UVB dose. One month old cultures stimulated with ascorbic acid were also assessed. RESULTS After UVB radiation, fibroblasts appear irregular in size, lose their alignment and show a decrease in fluorescence lifetime. One month-old fibroblasts, producing collagen fibres after stimulation with ascorbic acid, appear as small roundish structures intermingled by filaments showing a granular arrangement. CONCLUSION The combination of MPT and FLIM may be useful for the in vitro study of cell modifications induced by injurious or protective agents and drugs.
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Affiliation(s)
- Seidenari Stefania
- Department of Dermatology, University of Modena and Reggio Emilia, 41124 Modena, Italy
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Rollakanti KR, Kanick SC, Davis SC, Pogue BW, Maytin EV. Techniques for fluorescence detection of protoporphyrin IX in skin cancers associated with photodynamic therapy. ACTA ACUST UNITED AC 2013; 2:287-303. [PMID: 25599015 DOI: 10.1515/plm-2013-0030] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Photodynamic therapy (PDT) is a treatment modality that uses a specific photosensitizing agent, molecular oxygen, and light of a particular wavelength to kill cells targeted by the therapy. Topically administered aminolevulinic acid (ALA) is widely used to effectively treat cancerous and precancerous skin lesions, resulting in targeted tissue damage and little to no scarring. The targeting aspect of the treatment arises from the fact that ALA is preferentially converted into protoporphyrin IX (PpIX) in neoplastic cells. To monitor the amount of PpIX in tissues, techniques have been developed to measure PpIX-specific fluorescence, which provides information useful for monitoring the abundance and location of the photosensitizer before and during the illumination phase of PDT. This review summarizes the current state of these fluorescence detection techniques. Non-invasive devices are available for point measurements, or for wide-field optical imaging, to enable monitoring of PpIX in superficial tissues. To gain access to information at greater tissue depths, multi-modal techniques are being developed which combine fluorescent measurements with ultrasound or optical coherence tomography, or with microscopic techniques such as confocal or multiphoton approaches. The tools available at present, and newer devices under development, offer the promise of better enabling clinicians to inform and guide PDT treatment planning, thereby optimizing therapeutic outcomes for patients.
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Affiliation(s)
- Kishore R Rollakanti
- Department of Chemical and Biomedical Engineering, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA; and Department of Biomedical Engineering, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Stephen C Kanick
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA
| | - Scott C Davis
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA
| | - Edward V Maytin
- Department of Chemical and Biomedical Engineering, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA; Department of Biomedical Engineering, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA; and Department of Dermatology, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Arginelli F, Manfredini M, Bassoli S, Dunsby C, French P, König K, Magnoni C, Ponti G, Talbot C, Seidenari S. High resolution diagnosis of common nevi by multiphoton laser tomography and fluorescence lifetime imaging. Skin Res Technol 2012; 19:194-204. [DOI: 10.1111/srt.12035] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Federica Arginelli
- Department of Dermatology; University of Modena and Reggio Emilia; Modena Italy
| | - Marco Manfredini
- Department of Dermatology; University of Modena and Reggio Emilia; Modena Italy
| | - Sara Bassoli
- Department of Dermatology; University of Modena and Reggio Emilia; Modena Italy
| | - Christopher Dunsby
- Department of Physics; South Kensington Campus; Imperial College London London UK
| | - Paul French
- Department of Physics; South Kensington Campus; Imperial College London London UK
| | - Karsten König
- Department of Biophotonics and Lasertechnology; Saarland University; Saarbrücken Germany
- JenLab GmbH; Jena Germany
| | - Cristina Magnoni
- Department of Dermatology; University of Modena and Reggio Emilia; Modena Italy
| | - Giovanni Ponti
- Department of Dermatology; University of Modena and Reggio Emilia; Modena Italy
- Department of Clinical and Diagnostic Medicine and Public Health; University Hospital of Modena and Reggio Emilia; Italy
| | - Clifford Talbot
- Department of Physics; South Kensington Campus; Imperial College London London UK
| | - Stefania Seidenari
- Department of Dermatology; University of Modena and Reggio Emilia; Modena Italy
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Couet F, Mantovani D. Perspectives on the advanced control of bioreactors for functional vascular tissue engineering in vitro. Expert Rev Med Devices 2012; 9:233-9. [PMID: 22702253 DOI: 10.1586/erd.12.15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Tissue engineering aims to produce tissues using cells and materials. The action of designing tissues involves observing the process of growth to understand its underlying mechanisms. It requires manipulation of the critical parameters for cell growth and remodeling to produce structured tissues and functional organs. Tissue engineers face the challenge of orchestrating the signals in a cell's microenvironment to efficiently grow an anisotropic and hierarchical tissue. It can be performed in vivo through the design of bioactive scaffolds and manipulation of biological signals using growth factors. It can also be performed in vitro in a controlled environment called the bioreactor. This article addresses the matter of finding the optimal dynamic sequence of culture conditions in a bioreactor for the maturation of tissues. Artificial intelligence and optimal control are accelerating technologies towards an understanding of tissue regeneration. The particular example of the functional engineering of small-diameter blood vessels has been chosen to illustrate this idea.
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Affiliation(s)
- Frédéric Couet
- Laboratory for Biomaterials and Bioengineering, Department of Min-Met-Materials Engineering and University Hospital Research Center, Laval University, Québec City, QC, G1V 0A6, Canada
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Riemann I, Le Harzic R, Mpoukouvalas K, Heimann A, Kempski O, Charalampaki P. Sub-cellular tumor identification and markerless differentiation in the rat brain in vivo by multiphoton microscopy. Lasers Surg Med 2012; 44:719-25. [PMID: 23018677 DOI: 10.1002/lsm.22079] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2012] [Indexed: 11/07/2022]
Abstract
OBJECTIVE/BACKGROUND Aim of the current study was to localize and differentiate between tumor (glioma) and healthy tissue in rat brains on a cellular level. Near-infrared multiphoton microscopy takes advantage of the simultaneous absorption of two or more photons to analyze various materials such as cell and tissue components via the observation of endogenous fluorophores such as NAD(P)H, FAD, porphyrins, melanin, elastin, and collagen, with a very high resolution, without inducing the problems of photo-bleaching on out-of-focus areas. METHODS In vitro and in vivo studies on healthy rat brains as well as C6 glioma cell line allografts have been performed. Near-infrared laser pulses (λ = 690-1060 nm, τ ~140 fs) generated by an ultrafast Ti:Sapphire tunable laser system (Chameleon, Coherent GmbH, Santa Clara, CA) were coupled into a laser scanning microscope (LSM 510 META, Carl Zeiss, Germany) to observe high quality images. RESULTS Several image acquisitions have been performed by varying the zoom scale of the multiphoton microscope, image acquisition time and the wavelength (765, 840 nm) to detect various tissue components. With a penetration depth of ~200 µm in vitro and about 30-60 µm in vivo into the brain tissue it was possible to differentiate between tumor and healthy brain tissue even through thin layers of blood. CONCLUSION Near-infrared multiphoton microscopy allows the observation and possibly differentiation between tumor (glioma) and healthy tissue in rat brains on a cellular level. Our findings suggest that a further miniaturization of this technology might be very useful for scientific and clinical applications in neurosurgery.
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Affiliation(s)
- Iris Riemann
- Fraunhofer Institute for Biomedical Engineering, Ensheimer Str 48, 66386 St Ingbert, Germany.
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Seidenari S, Arginelli F, Dunsby C, French P, König K, Magnoni C, Manfredini M, Talbot C, Ponti G. Multiphoton laser tomography and fluorescence lifetime imaging of basal cell carcinoma: morphologic features for non-invasive diagnostics. Exp Dermatol 2012; 21:831-6. [PMID: 22882324 DOI: 10.1111/j.1600-0625.2012.01554.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2012] [Indexed: 11/28/2022]
Abstract
Multiphoton laser tomography (MPT) combined with fluorescence lifetime imaging (FLIM) is a non-invasive imaging technique, which gives access to the cellular and extracellular morphology of the skin. The aim of our study was to assess the sensitivity and specificity of MPT/FLIM descriptors for basal cell carcinoma (BCC), to improve BCC diagnosis and the identification of tumor margins. In the preliminary study, FLIM images referring to 35 BCCs and 35 healthy skin samples were evaluated for the identification of morphologic descriptors characteristic of BCC. In the main study, the selected parameters were blindly evaluated on a test set comprising 63 BCCs, 63 healthy skin samples and 66 skin lesions. Moreover, FLIM values inside a region of interest were calculated on 98 healthy skin and 98 BCC samples. In the preliminary study, three epidermal descriptors and 7 BCC descriptors were identified. The specificity of the diagnostic criteria versus 'other lesions' was extremely high, indicating that the presence of at least one BCC descriptor makes the diagnosis of 'other lesion' extremely unlikely. FLIM values referring to BCC cells significantly differed from those of healthy skin. In this study, we identified morphological and numerical descriptors enabling the differentiation of BCC from other skin disorders and its distinction from healthy skin in ex vivo samples. In future, MPT/FLIM may be applied to skin lesions to provide direct clinical guidance before biopsy and histological examination and for the identification of tumor margins allowing a complete surgical removal.
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Affiliation(s)
- Stefania Seidenari
- Department of Dermatology, University of Modena and Reggio Emilia, Modena, Italy.
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59
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Seidenari S, Arginelli F, Bassoli S, Cautela J, Cesinaro AM, Guanti M, Guardoli D, Magnoni C, Manfredini M, Ponti G, König K. Diagnosis of BCC by multiphoton laser tomography. Skin Res Technol 2012; 19:e297-304. [PMID: 22776020 DOI: 10.1111/j.1600-0846.2012.00643.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND/PURPOSE Multiphoton Laser Tomography (MPT) is a non-linear optical technique that gives access to morphology and structure of both cells and extracellular matrix of the skin through the combination of autofluorescence imaging and second harmonic generation (SHG). The aim of this study was to identify MPT descriptors on ex vivo specimens of basal cell carcinoma (BCC) to assess the sensitivity and specificity of these criteria for the diagnosis of BCC and its differentiation from other skin tumours, inflammatory diseases and healthy skin. METHODS In the preliminary study, MPT images referring to 24 BCCs and 24 healthy skin samples were simultaneously evaluated by three observers for the identification of features characteristic of BCC. In the main study, the presence/absence of the descriptors identified in the preliminary study was blindly evaluated on a test set, comprising 66 BCCs, 66 healthy skin samples and 66 skin lesions, including 23 nevi, 8 melanomas, 17 skin tumours and other skin lesions by 3 independent observers. RESULTS In the preliminary study, three epidermal descriptors and six descriptors for BCC were identified. The latter included aligned elongated cells, double alignment of cells, cell nests with palisading and phantom islands. From the test set, 56 BCCs were correctly diagnosed, whereas in 10 cases the diagnosis was 'other lesions'. However, it was always possible to exclude the diagnosis of BCC in healthy skin and other lesion samples. Thus, overall sensitivity of the method was 84.85, whereas a specificity of 100% was observed with respect to both healthy skin and 'other lesions'. CONCLUSIONS This study describes new morphological descriptors of BCC enabling its characterization and its distinction from healthy skin and other skin lesions in ex vivo samples, and demonstrates for the first time that MPT represents a sensitive and specific technique for the diagnosis of BCC.
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Affiliation(s)
- Stefania Seidenari
- Department of Dermatology, University of Modena and Reggio Emilia, Modena, Italy.
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Wang S, Zhao J, Lui H, He Q, Zeng H. In vivonear-infrared autofluorescence imaging of pigmented skin lesions: methods, technical improvements and preliminary clinical results. Skin Res Technol 2012; 19:20-6. [DOI: 10.1111/j.1600-0846.2012.00632.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2012] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | - Qingli He
- Institue of Photonics and Photon-Technology and Department of Physics; Northwest University; Xi'an; Shaanxi; China
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Quinn KP, Bellas E, Fourligas N, Lee K, Kaplan DL, Georgakoudi I. Characterization of metabolic changes associated with the functional development of 3D engineered tissues by non-invasive, dynamic measurement of individual cell redox ratios. Biomaterials 2012; 33:5341-8. [PMID: 22560200 DOI: 10.1016/j.biomaterials.2012.04.024] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 04/08/2012] [Indexed: 12/26/2022]
Abstract
Non-invasive approaches to assess tissue function could improve significantly current methods to diagnose diseases and optimize engineered tissues. In this study, we describe a two-photon excited fluorescence microscopy approach that relies entirely on endogenous fluorophores to dynamically quantify functional metabolic readouts from individual cells within three-dimensional engineered tissues undergoing adipogenic differentiation over six months. Specifically, we employ an automated approach to analyze 3D image volumes and extract a redox ratio of metabolic cofactors. We identify a decrease in redox ratio over the first two months of culture that is associated with stem cell differentiation and lipogenesis. In addition, we demonstrate that the presence of endothelial cells facilitate greater cell numbers deeper within the engineered tissues. Since traditional assessments of engineered tissue structure and function are destructive and logistically intensive, this non-destructive, label-free approach offers a potentially powerful high-content characterization tool for optimizing tissue engineering protocols and assessing engineered tissue implants.
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Affiliation(s)
- Kyle P Quinn
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
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63
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Affiliation(s)
- Francisco Zaera
- Department of Chemistry, University of California, Riverside, California 92521, United States
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64
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Multiphoton microscopy. a powerful tool in skin research and topical drug delivery science. J Drug Deliv Sci Technol 2012. [DOI: 10.1016/s1773-2247(12)50036-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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65
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Multiphoton laser microscopy and fluorescence lifetime imaging for the evaluation of the skin. Dermatol Res Pract 2011; 2012:810749. [PMID: 22203841 PMCID: PMC3235701 DOI: 10.1155/2012/810749] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 08/30/2011] [Indexed: 12/02/2022] Open
Abstract
Multiphoton laser microscopy is a new, non-invasive technique providing access to the skin at a cellular and subcellular level, which is based both on autofluorescence and fluorescence lifetime imaging. Whereas the former considers fluorescence intensity emitted by epidermal and dermal fluorophores and by the extra-cellular matrix, fluorescence lifetime imaging (FLIM), is generated by the fluorescence decay rate. This innovative technique can be applied to the study of living skin, cell cultures and ex vivo samples. Although still limited to the clinical research field, the development of multiphoton laser microscopy is thought to become suitable for a practical application in the next few years: in this paper, we performed an accurate review of the studies published so far, considering the possible fields of application of this imaging method and providing high quality images acquired in the Department of Dermatology of the University of Modena.
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Intravital three-dimensional dynamic pathology of experimental colitis in living mice using two-photon laser scanning microscopy. J Gastrointest Surg 2011; 15:1842-50. [PMID: 21796457 DOI: 10.1007/s11605-011-1632-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 07/12/2011] [Indexed: 01/31/2023]
Abstract
BACKGROUND Intravital three-dimensional (3D) visualization of treatment efficacy in experimental colitis in living mice using two-photon laser scanning microscopy (TPLSM) has not been described. METHODS Colitis was induced with dextran sulfate sodium (DSS) in green fluorescent protein (GFP) transgenic mice. The 3D tomographic image of DSS-induced colitis with or without prednisolone was obtained intravitally using TPLSM. A serosal-approaching method was developed, by which we could observe all layers of the cecum from serosa to luminal mucosa without opening and everting the cecum. The dynamic pathology and treatment efficacy were assessed in the same mouse on several occasions. RESULTS The time-lapse 3D tomographic movie of DSS-induced colitis was obtained in living mice at a magnification of greater than ×600, which demonstrated irregularity of crypts, disappearance of crypts, inflammatory cell infiltrates in the lamina propria, and abscess formation at the bottom of crypts. Intravital TPLSM in the same mice demonstrated fewer infiltrating leukocytes and crypt abscesses on day 14 in the steroid group compared with the nonsteroid group. CONCLUSIONS Intravital 3D tomographic visualization of experimental colitis using TPLSM in combination with the serosal-approaching method can provide dynamic pathology at a high magnification, which may be useful in evaluating treatment efficacy in the same living mice.
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67
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Second harmonic generation and multiphoton microscopic detection of collagen without the need for species specific antibodies. Burns 2011; 37:1001-9. [DOI: 10.1016/j.burns.2011.03.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 02/12/2011] [Accepted: 03/21/2011] [Indexed: 11/22/2022]
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Pudlas M, Koch S, Bolwien C, Thude S, Jenne N, Hirth T, Walles H, Schenke-Layland K. Raman spectroscopy: a noninvasive analysis tool for the discrimination of human skin cells. Tissue Eng Part C Methods 2011; 17:1027-40. [PMID: 21774693 DOI: 10.1089/ten.tec.2011.0082] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Noninvasive monitoring of tissue-engineered (TE) constructs during their in vitro maturation or postimplantation in vivo is highly relevant for graft evaluation. However, traditional methods for studying cell and matrix components in engineered tissues such as histology, immunohistochemistry, or biochemistry require invasive tissue processing, resulting in the need to sacrifice of TE constructs. Raman spectroscopy offers the unique possibility to analyze living cells label-free in situ and in vivo solely based on their phenotype-specific biochemical fingerprint. In this study, we aimed to determine the applicability of Raman spectroscopy for the noninvasive identification and spectral separation of primary human skin fibroblasts, keratinocytes, and melanocytes, as well as immortalized keratinocytes (HaCaT cells). Multivariate analysis of cell-type-specific Raman spectra enabled the discrimination between living primary and immortalized keratinocytes. We further noninvasively distinguished between fibroblasts, keratinocytes, and melanocytes. Our findings are especially relevant for the engineering of in vitro skin models and for the production of artificial skin, where both the biopsy and the transplant consist of several cell types. To realize a reproducible quality of TE skin, the determination of the purity of the cell populations as well as the detection of potential molecular changes are important. We conclude therefore that Raman spectroscopy is a suitable tool for the noninvasive in situ quality control of cells used in skin tissue engineering applications.
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Affiliation(s)
- Marieke Pudlas
- Department of Cell and Tissue Engineering, Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB), Stuttgart, Germany
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Hwang YJ, Larsen J, Krasieva TB, Lyubovitsky JG. Effect of genipin crosslinking on the optical spectral properties and structures of collagen hydrogels. ACS APPLIED MATERIALS & INTERFACES 2011; 3:2579-84. [PMID: 21644569 PMCID: PMC3189483 DOI: 10.1021/am200416h] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Genipin, a natural cross-linking reagent extracted from the fruits of Gardenia jasminoides, can be effectively employed in tissue engineering applications due to its low cytotoxicity and high biocompatibility. The cross-linking of collagen hydrogels with genipin was followed with one-photon fluorescence spectroscopy, second harmonic generation, fluorescence and transmission electron microscopy. The incubation with genipin induced strong auto-fluorescence within the collagen hydrogels. The fluorescence emission maximum of the fluorescent adducts formed by genipin exhibit a strong dependence on the excitation wavelength. The emission maximum is at 630 nm when we excite the cross-linked samples with 590 nm light and shifts to 462 nm when we use 400 nm light instead. The fluorescence imaging studies show that genipin induces formation of long aggregated fluorescent strands throughout the depth of samples. The second harmonic generation (SHG) imaging studies suggest that genipin partially disaggregates 10 μm "fiberlike" collagen structures because of the formation of these fluorescent cross-links. Transmission electron microscopy (TEM) studies reveal that genipin largely eliminates collagen's characteristic native fibrillar striations. Our study is the first one to nondestructively follow and identify the structure within collagen hydrogels in situ and to sample structures formed on both micro- and nanoscales. Our findings suggest that genipin cross-linking of collagen follows a complex mechanism and this compound modifies the structure within the collagen hydrogels in both micro- and nanoscale.
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Affiliation(s)
- Yu-Jer Hwang
- Cell Molecular and Developmental Biology Program (CMBD), University of California Riverside, Riverside, California 9252, USA
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Grosberg LE, Radosevich AJ, Asfaha S, Wang TC, Hillman EMC. Spectral characterization and unmixing of intrinsic contrast in intact normal and diseased gastric tissues using hyperspectral two-photon microscopy. PLoS One 2011; 6:e19925. [PMID: 21603623 PMCID: PMC3095627 DOI: 10.1371/journal.pone.0019925] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 04/21/2011] [Indexed: 11/18/2022] Open
Abstract
Background Living tissues contain a range of intrinsic fluorophores and sources of second harmonic generation which provide contrast that can be exploited for fresh tissue imaging. Microscopic imaging of fresh tissue samples can circumvent the cost and time associated with conventional histology. Further, intrinsic contrast can provide rich information about a tissue's composition, structure and function, and opens the potential for in-vivo imaging without the need for contrast agents. Methodology/Principal Findings In this study, we used hyperspectral two-photon microscopy to explore the characteristics of both normal and diseased gastrointestinal (GI) tissues, relying only on their endogenous fluorescence and second harmonic generation to provide contrast. We obtained hyperspectral data at subcellular resolution by acquiring images over a range of two-photon excitation wavelengths, and found excitation spectral signatures of specific tissue types based on our ability to clearly visualize morphology. We present the two-photon excitation spectral properties of four major tissue types that are present throughout the GI tract: epithelium, lamina propria, collagen, and lymphatic tissue. Using these four excitation signatures as basis spectra, linear unmixing strategies were applied to hyperspectral data sets of both normal and neoplastic tissue acquired in the colon and small intestine. Our results show that hyperspectral unmixing with excitation spectra allows segmentation, showing promise for blind identification of tissue types within a field of view, analogous to specific staining in conventional histology. The intrinsic spectral signatures of these tissue types provide information relating to their biochemical composition. Conclusions/Significance These results suggest hyperspectral two-photon microscopy could provide an alternative to conventional histology either for in-situ imaging, or intraoperative ‘instant histology’ of fresh tissue biopsies.
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Affiliation(s)
- Lauren E Grosberg
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering, Columbia University, New York, New York, United States of America.
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71
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Applications of multiphoton tomographs and femtosecond laser nanoprocessing microscopes in drug delivery research. Adv Drug Deliv Rev 2011; 63:388-404. [PMID: 21514335 DOI: 10.1016/j.addr.2011.03.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 02/12/2011] [Accepted: 03/02/2011] [Indexed: 02/05/2023]
Abstract
Multiphoton tomography for in vivo high-resolution multidimensional imaging has been used in clinical investigations and small animal studies. The novel femtosecond laser tomographs have been employed to detect cosmetics and pharmaceutical components in situ as well as to study the interaction of drugs with intratissue cells and the extracellular matrix under physiological conditions. Applications include the intra-tissue accumulation of sunscreen nanoparticles in humans, the monitoring the metabolic status of patients with dermatitis, the biosynthesis of collagen after administration of anti-aging products, and the detection of porphyrins after application of 5-aminolevulinic acid. More than 2000 patients and volunteers in Europe, Australia, and Asia have been investigated with these unique tomographs. In addition, femtosecond laser nanoprocessing microscopes have been employed for targeted delivery and deposition in body organs, optical transfection and optical cleaning of stem cells, as well as for the optical transfer of molecular beacons to track microRNAs. These diverse applications highlight the capacity for multiphoton tomography and femtosecond laser nanoprocessing tools to advance drug delivery research.
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72
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Hwang YJ, Lyubovitsky JG. Collagen hydrogel characterization: multi-scale and multi-modality approach. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2011; 3:529-536. [PMID: 32938068 DOI: 10.1039/c0ay00381f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The complex supramolecular architecture of collagen biopolymer plays an important role in tissue development and integrity. Developing methods to report on collagen structures assembled in vitro would accelerate the pace of utilizing it in biomedical applications. Employing imaging techniques and turbidity measurements, we mapped the light scattering properties of 3D collagen hydrogels formed at initial concentrations of 1 mg ml-1 to about 5 mg ml-1 and several incubation temperatures. The transmission electron microscopy (TEM) images show that collagen scattering features consist of both native-like fibrils and filamentous structures that do not have the characteristic fibrillar striation observed in this protein. Spindle-shaped fibrils appear at the concentrations of 1, 2, 2.5 and 4 mg ml-1 and the spiral-shaped fibrils are formed at the concentrations of 2 and 2.5 mg ml-1. The multiphoton microscopy (MPM) images reveal that in the 3D collagen hydrogels a unified relationship between second harmonic generation (SHG) signal directionality and fibril morphology and/or sizes is not likely. The MPM images, however, showed important micro-structural details. These details lead us to conclude that the dependence of SHG signals on the number of interfaces created upon assembly of 3D collagen hydrogels can account for the strength of the detected backscattered signals.
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Affiliation(s)
- Yu-Jer Hwang
- Cell, Molecular and Developmental Biology Graduate Program, University of California Riverside, Riverside, California 92521, USA.
| | - Julia G Lyubovitsky
- Department of Bioengineering, University of California Riverside, Riverside, California 92521, USA.
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Abstract
BACKGROUND This review focuses on looking at recent developments in the non-invasive imaging of skin, in particular at how such imaging may be used at present or in the future to detect cutaneous melanoma. METHODS A MEDLINE search was performed for papers using imaging techniques to evaluate cutaneous melanoma, including melanoma metastasis. RESULTS Nine different techniques were found: dermoscopy, confocal laser scanning microscopy (including multiphoton microscopy), optical coherence tomography, high frequency ultrasound, positron emission tomography, magnetic resonance imaging, and Fourier, Raman, and photoacoustic spectroscopies. This review contrasts the effectiveness of these techniques when seeking to image melanomas in skin. CONCLUSIONS Despite the variety of techniques available for detecting melanoma, there remains a critical need for a high-resolution technique to answer the question of whether tumours have invaded through the basement membrane.
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Affiliation(s)
- Louise Smith
- Department of Engineering Materials, Kroto Research Institute, University of Sheffield, Sheffield, UK
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74
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Tracking nanoparticles in three-dimensional tissue-engineered models using confocal laser scanning microscopy. Methods Mol Biol 2011; 695:41-51. [PMID: 21042964 DOI: 10.1007/978-1-60761-984-0_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Here we describe a method for imaging the position of nanoparticles within a 3D tissue-engineered model using confocal laser scanning microscopy (CLSM). The ability to track diffusion of nanoparticles in vitro is an important part of trans-dermal and trans-mucosal drug delivery development as well as for intra-epithelial drug delivery. Using 3D tissue-engineered models enables us to image diffusion in vitro in a physiologically relevant way; not possible in two-dimensional monolayer cultures (MacNeil, Nature 445:874-880, 2007; Hearnden et al., Pharmaceutical Res. 26(7):1718-1728, 2009). CLSM enables imaging of viable in vitro models in three dimensions with good spatial and axial resolution (Georgakoudi et al., Tissue Eng 14:1-20, 2008; Schenke-Layland et al., Adv. Drug Del. Rev. 58:878-896, 2006). Here we show that fluorescently labelled nanoparticles can be visualised, quantified, and their position within the cell can be determined using CLSM.
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75
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Meyer T, Bergner N, Bielecki C, Krafft C, Akimov D, Romeike BFM, Reichart R, Kalff R, Dietzek B, Popp J. Nonlinear microscopy, infrared, and Raman microspectroscopy for brain tumor analysis. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:021113. [PMID: 21361676 DOI: 10.1117/1.3533268] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Contemporary brain tumor research focuses on two challenges: First, tumor typing and grading by analyzing excised tissue is of utmost importance for choosing a therapy. Second, for prognostication the tumor has to be removed as completely as possible. Nowadays, histopathology of excised tissue using haematoxylin-eosine staining is the gold standard for the definitive diagnosis of surgical pathology specimens. However, it is neither applicable in vivo, nor does it allow for precise tumor typing in those cases when only nonrepresentative specimens are procured. Infrared and Raman spectroscopy allow for very precise cancer analysis due to their molecular specificity, while nonlinear microscopy is a suitable tool for rapid imaging of large tissue sections. Here, unstained samples from the brain of a domestic pig have been investigated by a multimodal nonlinear imaging approach combining coherent anti-Stokes Raman scattering, second harmonic generation, and two photon excited fluorescence microscopy. Furthermore, a brain tumor specimen was additionally analyzed by linear Raman and Fourier transform infrared imaging for a detailed assessment of the tissue types that is required for classification and to validate the multimodal imaging approach. Hence label-free vibrational microspectroscopic imaging is a promising tool for fast and precise in vivo diagnostics of brain tumors.
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Affiliation(s)
- Tobias Meyer
- Institute of Photonic Technology e.V., Albert-Einstein-Strasse 9, 07745 Jena, Germany
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76
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Lammers G, Verhaegen PD, Ulrich MM, Schalkwijk J, Middelkoop E, Weiland D, Nillesen ST, Van Kuppevelt TH, Daamen WF. An Overview of Methods for the In Vivo Evaluation of Tissue-Engineered Skin Constructs. TISSUE ENGINEERING PART B-REVIEWS 2011; 17:33-55. [DOI: 10.1089/ten.teb.2010.0473] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Gerwen Lammers
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Pauline D.H.M. Verhaegen
- Association of Dutch Burn Centres, Red Cross Hospital, Beverwijk, The Netherlands
- Department of Plastic, Reconstructive, and Hand Surgery, Academic Medical Centre, Amsterdam, The Netherlands
| | - Magda M.W. Ulrich
- Department of Plastic, Reconstructive, and Hand Surgery, Academic Medical Centre, Amsterdam, The Netherlands
- Department of Plastic, Reconstructive and Hand Surgery, VU Medical Center, Amsterdam, The Netherlands
| | - Joost Schalkwijk
- Department of Dermatology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Esther Middelkoop
- Association of Dutch Burn Centres, Red Cross Hospital, Beverwijk, The Netherlands
- Department of Plastic, Reconstructive and Hand Surgery, VU Medical Center, Amsterdam, The Netherlands
| | - Daniela Weiland
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Suzan T.M. Nillesen
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Toin H. Van Kuppevelt
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Willeke F. Daamen
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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77
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Huang Z, Li Z, Chen R, Lin J, Li Y, Li C. In vitro imaging of thyroid tissues using two-photon excited fluorescence and second harmonic generation. Photomed Laser Surg 2010; 28 Suppl 1:S129-33. [PMID: 20649422 DOI: 10.1089/pho.2009.2563] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE To evaluate the feasibility of two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) imaging to discriminate the normal, nodular goiter and papillary cancerous thyroid tissue. MATERIALS AND METHODS In total, 45 fresh thyroid specimens (normal, 15; nodular goiter, 12; and papillary cancerous, 18) from 31 subjects were directly imaged by the TPEF and SHG combination method. RESULTS The microstructure of follicle and collagen structure in thyroid tissue were clearly identified, morphologic changes between normal, nodular goiter, and papillary cancerous thyroid tissue were well characterized by using two-photon excitation fluorescence. SHG imaging of the collagen matrix also revealed the differences between normal and abnormal. CONCLUSIONS Our preliminary study suggests that the TPEF and SHG combination method might be a useful tool in revealing pathologic changes in thyroid tissue.
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Affiliation(s)
- Zufang Huang
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Normal University, Fuzhou, P. R. China
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78
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Hwang YJ, Granelli J, Lyubovitsky JG. Multiphoton optical image guided spectroscopy method for characterization of collagen-based materials modified by glycation. Anal Chem 2010; 83:200-6. [PMID: 21141843 DOI: 10.1021/ac102235g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The cross-linking with reducing sugars, known as glycation, is used to increase stiffness and strength of tissues and artificial collagen-based scaffolds. Nondestructive characterization methods that report on the structures within these materials could clarify the effects of glycation. For doing this nondestructive evaluation, we employed an in situ one-photon fluorescence as well as multiphoton microscopy method that combined two-photon fluorescence and second harmonic generation signals. We incubated collagen hydrogels with glyceraldehyde, ribose, and glucose and observed an increase in the in situ fluorescence and structural alterations within the materials during the course of glycation. The two-photon fluorescence emission maximum was observed at about 460 nm. The fluorescence emission in the one-photon excitation experiment (λ(ex) = 360 nm) was broad with peaks centered at 445 and 460 nm. The 460 nm emission component subsequently became dominant during the course of glycation with glyceraldehyde. For the ribose, in addition to the 460 nm peak, the 445 nm component persisted. The glucose glycated hydrogels exhibited broad fluorescence that did not increase significantly even after 6 weeks. As determined from measuring the fluorescence intensity at the 460 nm maximum, glycation with glyceraldehyde was faster compared to ribose and generated stronger fluorescence signals. Upon excitation of glycated samples with 330 nm light, different emission peaks were observed.
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Affiliation(s)
- Yu-Jer Hwang
- Cell, Molecular and Developmental Biology Graduate Program, University of California Riverside, Riverside, California 92521, United States
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79
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Noninvasive multiphoton fluorescence microscopy resolves retinol and retinal condensation products in mouse eyes. Nat Med 2010; 16:1444-9. [PMID: 21076393 PMCID: PMC3057900 DOI: 10.1038/nm.2260] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 08/03/2010] [Indexed: 12/13/2022]
Abstract
Multi–photon excitation fluorescence microscopy (MPM) can image certain molecular processes in vivo. In the eye, fluorescent retinyl esters in sub–cellular structures called retinosomes mediate regeneration of the visual chromophore, 11–cis–retinal, by the visual cycle. But harmful fluorescent condensation products were also identified previously. We report that in wild type mice, excitation with λ ~730 nm identified retinosomes in the retinal pigment epithelium, whereas excitation with λ ~910 nm revealed at least one additional retinal fluorophore. The latter fluorescence was absent in eyes of genetically modified mice lacking a functional visual cycle, but accentuated in eyes of older WT mice and mice with defective clearance of all–trans–retinal, an intermediate in the visual cycle. MPM, a noninvasive imaging modality that facilitates concurrent monitoring of retinosomes along with potentially harmful products in aging eyes, has the potential to detect early molecular changes due to age–related macular degeneration and other defects in retinoid metabolism.
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80
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Xylas J, Alt-Holland A, Garlick J, Hunter M, Georgakoudi I. Intrinsic optical biomarkers associated with the invasive potential of tumor cells in engineered tissue models. BIOMEDICAL OPTICS EXPRESS 2010; 1:1387-1400. [PMID: 21258557 PMCID: PMC3018132 DOI: 10.1364/boe.1.001387] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 10/26/2010] [Accepted: 11/08/2010] [Indexed: 05/20/2023]
Abstract
This report assesses the ability of intrinsic two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) imaging to characterize features associated with the motility and invasive potential of epithelial tumor cells engineered in tissues. Distinct patterns of organization are found both within the cells and the matrix that depend on the adhesive properties of the cells as well as factors attributed to adjacent fibroblasts. TPEF images are analyzed using automated algorithms that reveal unique features in subcellular organization and cell spacing that correlate with the invasive potential. We expect that such features have significant diagnostic potential for basic in vitro studies that aim to improve our understanding of cancer development or response to treatments, and, ultimately can be applied in prognostic evaluation.
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Affiliation(s)
- Joanna Xylas
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, USA
| | - Addy Alt-Holland
- Division of Cancer Biology and Tissue Engineering, Department of Oral and Maxillofocial Pathology, School of Dental Medicine Tufts University, Boston, Massachusetts 02111, USA
| | - Jonathan Garlick
- Division of Cancer Biology and Tissue Engineering, Department of Oral and Maxillofocial Pathology, School of Dental Medicine Tufts University, Boston, Massachusetts 02111, USA
- Department of Endodontics, School of Dental Medicine Tufts University, Boston, Massachusetts 02111, USA
| | - Martin Hunter
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, USA
| | - Irene Georgakoudi
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, USA
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81
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Fritze O, Schleicher M, König K, Schenke-Layland K, Stock U, Harasztosi C. Facilitated noninvasive visualization of collagen and elastin in blood vessels. Tissue Eng Part C Methods 2010; 16:705-10. [PMID: 19803792 DOI: 10.1089/ten.tec.2009.0309] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Multiphoton imaging is a powerful tool for three-dimensional visualization of extracellular matrix components such as collagen and elastin in fresh, nonfixed, and nonembedded tissues. We have previously published data on the induction of the second harmonic generation signal of collagen and autofluorescence of elastin using a tunable multiphoton laser system. Without staining, a second harmonic generation signal was detected for collagen when excited at wavelength lambda(ex) = 840 nm. Switching the excitation wavelength to 760 nm enabled visualization of elastic fiber structures. A limitation of this technology is the laser-tuning process that requires calibration of the system in between the studies. Now we have developed a facilitated method for studying tissues and tissue equivalents that enables simultaneous visualization of collagen and elastin structures using only a single excitation wavelength of 840 nm in combination with two different band-pass filters. This facilitated method will expand the range of application by reducing required time and expenses for the laser system without reducing its capability.
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Affiliation(s)
- Olaf Fritze
- Department of Thoracic, Cardiac, and Vascular Surgery, University Hospital Tuebingen, Tuebingen, Germany.
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82
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Bilgin CC, Lund AW, Can A, Plopper GE, Yener B. Quantification of three-dimensional cell-mediated collagen remodeling using graph theory. PLoS One 2010; 5. [PMID: 20927339 PMCID: PMC2948014 DOI: 10.1371/journal.pone.0012783] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 08/20/2010] [Indexed: 11/24/2022] Open
Abstract
Background Cell cooperation is a critical event during tissue development. We present the first precise metrics to quantify the interaction between mesenchymal stem cells (MSCs) and extra cellular matrix (ECM). In particular, we describe cooperative collagen alignment process with respect to the spatio-temporal organization and function of mesenchymal stem cells in three dimensions. Methodology/Principal Findings We defined two precise metrics: Collagen Alignment Index and Cell Dissatisfaction Level, for quantitatively tracking type I collagen and fibrillogenesis remodeling by mesenchymal stem cells over time. Computation of these metrics was based on graph theory and vector calculus. The cells and their three dimensional type I collagen microenvironment were modeled by three dimensional cell-graphs and collagen fiber organization was calculated from gradient vectors. With the enhancement of mesenchymal stem cell differentiation, acceleration through different phases was quantitatively demonstrated. The phases were clustered in a statistically significant manner based on collagen organization, with late phases of remodeling by untreated cells clustering strongly with early phases of remodeling by differentiating cells. The experiments were repeated three times to conclude that the metrics could successfully identify critical phases of collagen remodeling that were dependent upon cooperativity within the cell population. Conclusions/Significance Definition of early metrics that are able to predict long-term functionality by linking engineered tissue structure to function is an important step toward optimizing biomaterials for the purposes of regenerative medicine.
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Affiliation(s)
- Cemal Cagatay Bilgin
- Computer Science Department, Rensselaer Polytechnic Institute, Troy, New York, United States of America
| | - Amanda W. Lund
- Biology Department, Rensselaer Polytechnic Institute, Troy, New York, United States of America
| | - Ali Can
- General Electric Global Research Center, Niskayuna, New York, United States of America
| | - George E. Plopper
- Biology Department, Rensselaer Polytechnic Institute, Troy, New York, United States of America
| | - Bülent Yener
- Computer Science Department, Rensselaer Polytechnic Institute, Troy, New York, United States of America
- * E-mail:
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83
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Wang BG, König K, Halbhuber KJ. Two-photon microscopy of deep intravital tissues and its merits in clinical research. J Microsc 2010; 238:1-20. [PMID: 20384833 DOI: 10.1111/j.1365-2818.2009.03330.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Multiphoton excitation laser scanning microscopy, relying on the simultaneous absorption of two or more photons by a molecule, is one of the most exciting recent developments in biomedical imaging. Thanks to its superior imaging capability of deeper tissue penetration and efficient light detection, this system becomes more and more an inspiring tool for intravital bulk tissue imaging. Two-photon excitation microscopy including 2-photon fluorescence and second harmonic generated signal microscopy is the most common multiphoton microscopic application. In the present review we take diverse ocular tissues as intravital samples to demonstrate the advantages of this approach. Experiments with registration of intracellular 2-photon fluorescence and extracellular collagen second harmonic generated signal microscopy in native ocular tissues are focused. Data show that the in-tandem combination of 2-photon fluorescence and second harmonic generated signal microscopy as two-modality microscopy allows for in situ co-localization imaging of various microstructural components in the whole-mount deep intravital tissues. New applications and recent developments of this high technology in clinical studies such as 2-photon-controlled drug release, in vivo drug screening and administration in skin and kidney, as well as its uses in tumourous tissues such as melanoma and glioma, in diseased lung, brain and heart are additionally reviewed. Intrinsic emission two-modal 2-photon microscopy/tomography, acting as an efficient and sensitive non-injurious imaging approach featured by high contrast and subcellular spatial resolution, has been proved to be a promising tool for intravital deep tissue imaging and clinical studies. Given the level of its performance, we believe that the non-linear optical imaging technique has tremendous potentials to find more applications in biomedical fundamental and clinical research in the near future.
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Affiliation(s)
- B-G Wang
- Laser Microscopy Research Unit, Institute of Microscopic Anatomy, Faculty of Medicine, Friedrich Schiller University of Jena. Teichgraben 7, 07743 Jena, Germany.
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84
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Abraham T, Hogg J. Extracellular matrix remodeling of lung alveolar walls in three dimensional space identified using second harmonic generation and multiphoton excitation fluorescence. J Struct Biol 2010; 171:189-96. [PMID: 20412859 DOI: 10.1016/j.jsb.2010.04.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 04/14/2010] [Accepted: 04/15/2010] [Indexed: 11/19/2022]
Abstract
The structural reorganization of extracellular matrix (ECM) is an important feature of peripheral lung tissue remodeling in chronic obstructive pulmonary disease (COPD). Ordered ECM macromolecules such as the fibril-forming collagens produce second harmonic generation (SHG) signal without the need for any exogenous label, while ECM macromolecules such as the elastin fibers generate MPEF signal due to their endogenous fluorescence characteristics. Both these signals can be captured simultaneously to provide spatially resolved 3D structural reorganization of ECM matrix. In this study, SHG and MPEF microscopy methods were used to examine structural remodeling of the ECM matrix in human lung alveolar walls undergoing severe emphysematous destruction. Flash frozen lung samples removed from two patients undergoing lung transplantation for severe COPD (n=4) were compared to similar samples from an unused donor lung (n=2) that served as a control. The imaging operations were performed directly on these tissue sections at least three different areas. The generated spatially resolved 3D images showed the distribution of collagen and elastin in the alveolar walls. In the case of the control, we found well ordered alveolar walls with a composite type structure made up of collagen bands and relatively fine elastic fibers. In contrast, lung tissues undergoing emphysematous destruction were highly disorganized with significantly increased alveolar wall thickness compared to the control. We conclude that these non-invasive imaging modalities provide spatially resolved 3D images with spectral specificities that are sensitive enough to identity the ECM structural changes associated with emphysematous destruction.
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Affiliation(s)
- Thomas Abraham
- The James Hogg Research Centre, Heart+Lung Institute at St. Paul's Hospital, University of British Columbia, Vancouver, Canada V6Z 1Y6.
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85
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Two-photon microscopy for non-invasive, quantitative monitoring of stem cell differentiation. PLoS One 2010; 5:e10075. [PMID: 20419124 PMCID: PMC2855700 DOI: 10.1371/journal.pone.0010075] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 03/04/2010] [Indexed: 11/24/2022] Open
Abstract
Background The engineering of functional tissues is a complex multi-stage process, the success of which depends on the careful control of culture conditions and ultimately tissue maturation. To enable the efficient optimization of tissue development protocols, techniques suitable for monitoring the effects of added stimuli and induced tissue changes are needed. Methodology/Principal Findings Here, we present the quantitative use of two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) as a noninvasive means to monitor the differentiation of human mesenchymal stem cells (hMSCs) using entirely endogenous sources of contrast. We demonstrate that the individual fluorescence contribution from the intrinsic cellular fluorophores NAD(P)H, flavoproteins and lipofuscin can be extracted from TPEF images and monitored dynamically from the same cell population over time. Using the redox ratio, calculated from the contributions of NAD(P)H and flavoproteins, we identify distinct patterns in the evolution of the metabolic activity of hMSCs maintained in either propagation, osteogenic or adipogenic differentiation media. The differentiation of these cells is mirrored by changes in cell morphology apparent in high resolution TPEF images and by the detection of collagen production via SHG imaging. Finally, we find dramatic increases in lipofuscin levels in hMSCs maintained at 20% oxygen vs. those in 5% oxygen, establishing the use of this chromophore as a potential biomarker for oxidative stress. Conclusions/Significance In this study we demonstrate that it is possible to monitor the metabolic activity, morphology, ECM production and oxidative stress of hMSCs in a non-invasive manner. This is accomplished using generally available multiphoton microscopy equipment and simple data analysis techniques, such that the method can widely adopted by laboratories with a diversity of comparable equipment. This method therefore represents a powerful tool, which enables researchers to monitor engineered tissues and optimize culture conditions in a near real time manner.
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86
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Breunig HG, Studier H, König K. Multiphoton excitation characteristics of cellular fluorophores of human skin in vivo. OPTICS EXPRESS 2010; 18:7857-71. [PMID: 20588627 DOI: 10.1364/oe.18.007857] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In vivo multiphoton tomography with a wavelength-tunable femtosecond laser has been performed to investigate the autofluorescence intensity of major endogenous fluorophores of human skin in dependence on the excitation wavelength. In high-resolution multiphoton images of different skin layers, clear trends were found for fluorophores like keratin, NAD(P)H, melanin as well as for the elastin and collagen networks. The analysis of the measurements is supplemented by additional measurements of fluorescence lifetime imaging and signal-decay curves by time-correlated single-photon counting.
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87
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Begue NJ, Simpson GJ. Chemically selective analysis of molecular monolayers by nonlinear optical stokes ellipsometry. Anal Chem 2010; 82:559-66. [PMID: 20000785 DOI: 10.1021/ac901832u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The application of nonlinear optical Stokes ellipsometry (NOSE) coupled with principal component analysis (PCA) is demonstrated for the chemically selective analysis of molecular monolayers. NOSE allows for rapid polarization measurements of nonlinear optical materials and thin surface films, which in turn benefits from comparably fast data analysis approaches. PCA combined with linear curve fitting techniques greatly reduce the analysis time relative to nonlinear curve fitting. NOSE-PCA is first validated with studies of z-cut quartz, followed by analysis of four thin dye films with similar nonlinear optical properties. The high precision of NOSE measurements combined with the rapid analysis time enabled chemical discrimination between different dyes and the practical realization of NOSE microscopy.
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Affiliation(s)
- Nathan J Begue
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette Indiana 47907, USA
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88
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Zhou J, Fritze O, Schleicher M, Wendel HP, Schenke-Layland K, Harasztosi C, Hu S, Stock UA. Impact of heart valve decellularization on 3-D ultrastructure, immunogenicity and thrombogenicity. Biomaterials 2010; 31:2549-54. [PMID: 20061016 DOI: 10.1016/j.biomaterials.2009.11.088] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 11/25/2009] [Indexed: 10/20/2022]
Abstract
Decellularized xenogeneic tissue represents an interesting material for heart valve tissue engineering. The prospect objective is removal of all viable cells while preserving extracellular matrix (ECM) integrity. The major concerns of all decellularization protocols remain ECM disruption, immunogenicity and thrombogenicity. Accordingly the aim of this study was visualization of ultrastructural ECM disruption and human immune response and thrombogenicity using different decellularization protocols of porcine heart valves. Porcine pulmonary leaflets were decellularized with four different protocols: sodium deoxycholate, sodium dedecylsulfate, trypsin/EDTA, and trypsin-detergent-nuclease. Then the tissues were processed for histology and two-photon laser scanning microscopy (LSM). For thrombogenicity and immunogenicity testing tissues were incubated with human blood. The histological examination revealed no remaining cells and no significant differences in the ECM histoarchitecture in any group. LSM detected significant ECM alterations in all groups except sodium deoxycholate group with an almost completely preserved ECM. There was no increased immunogenicity between fresh and decellularized tissue. Compared to GA-fixed tissue however significantly increased immune responses and thrombogenicity was observed in all protocols. From our experiment, sodium deoxycholate enables cell removal with almost complete preservation of ECM structures. And all of these four decellularization protocols affected human immunological response and increased thrombogenicity.
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Affiliation(s)
- Jianye Zhou
- Thoracic, Cardiac and Vascular Surgery, University Hospital Tübingen, 72076 Tübingen, Germany
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89
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Raub CB, Mahon S, Narula N, Tromberg BJ, Brenner M, George SC. Linking optics and mechanics in an in vivo model of airway fibrosis and epithelial injury. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:015004. [PMID: 20210444 PMCID: PMC2844131 DOI: 10.1117/1.3322296] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 11/20/2009] [Accepted: 12/18/2009] [Indexed: 05/28/2023]
Abstract
Chronic mucosal and submucosal injury can lead to persistent inflammation and tissue remodeling. We hypothesized that microstructural and mechanical properties of the airway wall could be derived from multiphoton images. New Zealand White rabbits were intubated, and the tracheal epithelium gently denuded every other day for five days (three injuries). Three days following the last injury, the tracheas were excised for multiphoton imaging, mechanical compression testing, and histological analysis. Multiphoton imaging and histology confirm epithelial denudation, mucosal ulceration, subepithelial thickening, collagen deposition, immune cell infiltration, and a disrupted elastin network. Elastase removes the elastin network and relaxes the collagen network. Purified collagenase removes epithelium with subtle subepithelial changes. Young's modulus [(E) measured in kiloPascal] was significantly elevated for the scrape injured (9.0+/-3.2) trachea, and both collagenase (2.6+/-0.4) and elastase (0.8+/-0.3) treatment significantly reduced E relative to control (4.1+/-0.7). E correlates strongly with second harmonic generation (SHG) signal depth decay for enzyme-treated and control tracheas (R(2)=0.77), but not with scrape-injured tracheas. We conclude that E of subepithelial connective tissue increases on repeated epithelial wounding, due in part to changes in elastin and collagen microstructure and concentration. SHG depth decay is sensitive to changes in extracellular matrix content and correlates with bulk Young's modulus.
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Affiliation(s)
- Christopher B Raub
- University of California, Irvine, Department of Biomedical Engineering, Irvine, California 92697-2730, USA
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90
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Zhu X, Zhuo S, Zheng L, Lu K, Jiang X, Chen J, Lin B. Quantified characterization of human cutaneous normal scar using multiphoton microscopy. JOURNAL OF BIOPHOTONICS 2010; 3:108-16. [PMID: 19768706 DOI: 10.1002/jbio.200910058] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The morphological alterations of human cutaneous normal scar were quantitatively analyzed using multiphoton microscopy (MPM) based on two-photon excited fluorescence and second harmonic generation. High-contrast, high-resolution images of normal scar and uninjured skin were obtained for comparison. In addition, some quantitative parameters have been extracted to quantitatively discriminate between normal scar and uninjured skin. The MPM combined with quantitative method enable a better understanding of microstructual alterations of the epidermis, elastic fiber, and collagen in normal scar. It may lead the way to making know the mechanism of normal scar formation and identifying feasible therapeutic options.
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Affiliation(s)
- Xiaoqin Zhu
- Institute of Laser and Optoelectronics Technology, Fujian Normal University, Fuzhou, P.R. China
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91
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Idris NM, Li Z, Ye L, Wei Sim EK, Mahendran R, Ho PCL, Zhang Y. Tracking transplanted cells in live animal using upconversion fluorescent nanoparticles. Biomaterials 2009; 30:5104-13. [DOI: 10.1016/j.biomaterials.2009.05.062] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 05/22/2009] [Indexed: 10/20/2022]
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92
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Georgakoudi I, Rice WL, Hronik-Tupaj M, Kaplan DL. Optical spectroscopy and imaging for the noninvasive evaluation of engineered tissues. TISSUE ENGINEERING PART B-REVIEWS 2009; 14:321-40. [PMID: 18844604 DOI: 10.1089/ten.teb.2008.0248] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Optical spectroscopy and imaging approaches offer the potential to noninvasively assess different aspects of the cellular, extracellular matrix, and scaffold components of engineered tissues. In addition, the combination of multiple imaging modalities within a single instrument is highly feasible, allowing acquisition of complementary information related to the structure, organization, biochemistry, and physiology of the sample. The ability to characterize and monitor the dynamic interactions that take place as engineered tissues develop promises to enhance our understanding of the interdependence of processes that ultimately leads to functional tissue outcomes. It is expected that this information will impact significantly upon our abilities to optimize the design of biomaterial scaffolds, bioreactors, and cell systems. Here, we review the principles and performance characteristics of the main methodologies that have been exploited thus far, and we present examples of corresponding tissue engineering studies.
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Affiliation(s)
- Irene Georgakoudi
- Biomedical Engineering Department, Tufts University, Medford, Massachusetts 02155, USA.
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93
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Hjortnaes J, Bouten CV, Van Herwerden LA, Gründeman PF, Kluin J. Translating Autologous Heart Valve Tissue Engineering from Bench to Bed. TISSUE ENGINEERING PART B-REVIEWS 2009; 15:307-17. [DOI: 10.1089/ten.teb.2008.0565] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jesper Hjortnaes
- Division of Heart & Lungs, Department of Clinical and Experimental Cardio-Thoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Carlijn V.C. Bouten
- Division of Heart & Lungs, Department of Clinical and Experimental Cardio-Thoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
- Cell & Tissue Engineering Laboratory, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Lex A. Van Herwerden
- Division of Heart & Lungs, Department of Clinical and Experimental Cardio-Thoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Paul F. Gründeman
- Division of Heart & Lungs, Department of Clinical and Experimental Cardio-Thoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jolanda Kluin
- Division of Heart & Lungs, Department of Clinical and Experimental Cardio-Thoracic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
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94
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Schenke-Layland K, Stock UA, Nsair A, Xie J, Angelis E, Fonseca CG, Larbig R, Mahajan A, Shivkumar K, Fishbein MC, MacLellan WR. Cardiomyopathy is associated with structural remodelling of heart valve extracellular matrix. Eur Heart J 2009; 30:2254-65. [PMID: 19561339 DOI: 10.1093/eurheartj/ehp267] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS To increase the supply, many countries harvest allograft valves from explanted hearts of transplant recipients with ischaemic (ICM) or dilated cardiomyopathy (DCM). This study determines the structural integrity of valves from cardiomyopathic hearts. METHODS AND RESULTS Extracellular matrix (ECM) was examined in human valves obtained from normal, ICM, and DCM hearts. To confirm if ECM changes were directly related to the cardiomyopathy, we developed a porcine model of chronic ICM. Histology and immunohistostaining, as well as non-invasive multiphoton and second harmonic generation (SHG) imaging revealed marked disruption of ECM structures in human valves from ICM and DCM hearts. The ECM was unaffected in valves from normal and acute ICM pigs, whereas chronic ICM specimens showed ECM alterations similar to those seen in ICM and DCM patients. Proteins and proteinases implicated in ECM remodelling, including Tenascin C, TGFbeta1, Cathepsin B, MMP2, were upregulated in human ICM and DCM, and porcine chronic ICM specimens. CONCLUSION Valves from cardiomyopathic hearts showed significant ECM deterioration with a disrupted collagen and elastic fibre network. It will be important to determine the impact of this ECM damage on valve durability and calcification in vivo if allografts are to be used from these donors.
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Affiliation(s)
- Katja Schenke-Layland
- Department of Medicine/Cardiology, Cardiovascular Research Laboratories, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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95
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Chernyavskiy O, Vannucci L, Bianchini P, Difato F, Saieh M, Kubínová L. Imaging of mouse experimental melanoma in vivo and ex vivo by combination of confocal and nonlinear microscopy. Microsc Res Tech 2009; 72:411-23. [DOI: 10.1002/jemt.20687] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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96
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Hearnden V, Lomas H, Macneil S, Thornhill M, Murdoch C, Lewis A, Madsen J, Blanazs A, Armes S, Battaglia G. Diffusion studies of nanometer polymersomes across tissue engineered human oral mucosa. Pharm Res 2009; 26:1718-28. [PMID: 19387800 DOI: 10.1007/s11095-009-9882-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Accepted: 03/19/2009] [Indexed: 11/29/2022]
Abstract
PURPOSE To measure the diffusion of nanometer polymersomes through tissue engineered human oral mucosa. METHODS In vitro models of full thickness tissue engineered oral mucosa (TEOM) were used to assess the penetration properties of two chemically different polymersomes comprising two of block copolymers, PMPC-PDPA and PEO-PDPA. These copolymers self-assemble into membrane-enclosed vesicular structures. Polymersomes were conjugated with fluorescent rhodamine in order to track polymersome diffusion. Imaging and quantification of the diffusion properties were assessed by confocal laser scanning microscopy (CLSM). RESULTS TEOM is morphologically similar to natural oral mucosa. Using CLSM, both formulations were detectable in the TEOM within 6 h and after 48 h both penetrated up to 80 microm into the TEOM. Diffusion of PMPC-PDPA polymersomes was widespread across the epithelium with intra-epithelial uptake, while PEO-PDPA polymersomes also diffused into the epithelium. CONCLUSIONS CLSM was found to be an effective and versatile method for analysing the level of diffusion of polymersomes into TEOM. The penetration and retention of PMPC-PDPA and PEO-PDPA polymersomes means they may have potential for intra-epithelial drug delivery and/or trans-epithelial delivery of therapeutic agents.
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Affiliation(s)
- Vanessa Hearnden
- Biomaterials and Tissue Engineering Group, Department of Engineering Materials, Kroto Research Institute, North Campus, University of Sheffield, Broad Lane, Sheffield S37HQ, UK
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97
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Jiang S, Zhang Y, Lim KM, Sim EKW, Ye L. NIR-to-visible upconversion nanoparticles for fluorescent labeling and targeted delivery of siRNA. NANOTECHNOLOGY 2009; 20:155101. [PMID: 19420539 DOI: 10.1088/0957-4484/20/15/155101] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Near-infrared (NIR)-to-visible upconversion fluorescent nanoparticles were synthesized and used for imaging and targeted delivery of small interfering RNA (siRNA) to cancer cells. Silica-coated NaYF(4) upconversion nanoparticles (UCNs) co-doped with lanthanide ions (Yb/Er) were synthesized. Folic acid and anti-Her2 antibody conjugated UCNs were used to fluorescently label the folate receptors of HT-29 cells and Her2 receptors of SK-BR-3 cells, respectively. The intracellular uptake of the folic acid and antibody conjugated UCNs was visualized using a confocal fluorescence microscope equipped with an NIR laser. siRNA was attached to anti-Her2 antibody conjugated UCNs and the delivery of these nanoparticles to SK-BR-3 cells was studied. Meanwhile, a luciferase assay was established to confirm the gene silencing effect of siRNA. Upconversion nanoparticles can serve as a fluorescent probe and delivery system for simultaneous imaging and delivery of biological molecules.
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Affiliation(s)
- Shan Jiang
- Division of Bioengineering, Faculty of Engineering, National University of Singapore, 117576, Singapore
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98
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Abstract
Recent advances in the use of nonlinear optical microscopy (NLOM) in skin microscopy are presented. Nonresonant spectroscopies including second harmonic generation, coherent anti-Stokes Raman and two-photon absorption are described and applications to problems in skin biology are detailed. These nonlinear techniques have several advantages over traditional microscopy methods that rely on one-photon excitation: intrinsic 3D imaging with <1 microm spatial resolution, decreased photodamage to tissue samples and penetration depths up to 1,000 microm with the use of near-infrared lasers. Thanks to these advantages, nonlinear optical spectroscopy has become a powerful tool to study the physical and biochemical properties of the skin. Structural information can be obtained using the response of endogenous chemical species in the skin, such as collagen or lipids, indicating that optical biopsy may replace current invasive, time-consuming traditional histology methods. Insertion of specific probe molecules into the skin provides the opportunity to monitor specific biochemical processes such as skin transport, molecular penetration, barrier homeostasis and ultraviolet radiation-induced reactive oxygen species generation. While the field is quite new, it seems likely that the use of NLOM to probe structure and biochemistry of live skin samples will only continue to grow.
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Affiliation(s)
- Kerry M Hanson
- Department of Chemistry, University of California at Riverside, Riverside, CA, USA
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99
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Lund AW, Stegemann JP, Plopper GE. Inhibition of ERK promotes collagen gel compaction and fibrillogenesis to amplify the osteogenesis of human mesenchymal stem cells in three-dimensional collagen I culture. Stem Cells Dev 2009; 18:331-41. [PMID: 18491946 DOI: 10.1089/scd.2008.0075] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tissue morphogenesis remains one of the least understood problems in cell and developmental biology. There is a disconnect between the mechanisms that apply to two-dimensional (2D) cultures and those seen in vivo. Three-dimensional (3D) culture presents a complex stimulus triggering cellular responses that are only partially understood. We compared 2D and 3D cultures of human mesenchymal stem cells in the presence of mitogen-activated protein kinase kinase (MEK) inhibitor, PD98059, to determine the role of extracellular signal-related kinase (ERK) in collagen-induced differentiation. 3D collagen I culture enhanced and accelerated the osteogenic differentiation of human mesenchymal stem cells (hMSC). Contrary to 2D results, the addition of PD98059 induced a significant amplification of osteogenic gene expression and matrix mineralization in 3D cultures. The inhibition of ERK altered cell-mediated compaction, proliferation, and resulted in the development of distinct tissue microstructure. Therefore, we suggest that the ability to reorganize collagen in 3D is an important step in ERK-mediated osteogenic differentiation. This work aims to propose a correlation between osteogenic differentiation and hMSC-directed collagen I remodeling. We present a potential mechanistic link (ERK) through which the three dimensionality of an engineered tissue acts to differentially induce and maintain cellular phenotype during tissue development.
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Affiliation(s)
- Amanda W Lund
- Department of Biology, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA
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100
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Makale M, McElroy M, O'Brien P, Hoffman RM, Guo S, Bouvet M, Barnes L, Ingulli E, Cheresh D. Extended-working-distance multiphoton micromanipulation microscope for deep-penetration imaging in live mice and tissue. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:024032. [PMID: 19405761 PMCID: PMC3098575 DOI: 10.1117/1.3103783] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We constructed a multiphoton (2-P) microscope with space to mount and operate microphysiology hardware, and still acquire high quality 2-P images of tumor cells deep within tissues of live mice. We reconfigured for nondescanned 2-P imaging, a dedicated electrophysiology microscope, the Nikon FN1. This microscope is compact, with retractable objectives, allowing more stage space. The instrument is fitted with long-working-distance objectives (2.5- to 3.5-mm WD) with a narrow bore, high NA, and efficient UV and IR light transmission. The system is driven by a powerful 3.5-W peak power pulsed Ti-sapphire laser with a broad tuning range. This 2-P system images a fluorescent standard to a depth of 750 to 800 microm, acquires images of murine pancreatic tumors in vivo, and also images fluorescently labeled T-cells inside live, externalized mouse lymph nodes. Effective imaging depths range between 100 and 500 microm. This compares favorably with the 100- to 300 microm micron depth attained by many 2-P systems, especially descanned 2-P instruments, and 40-microm-deep imaging with confocal microscopes. The greater depth penetration is attributable to the use of high-NA long-working-distance water-dipping lenses incorporated into a nondescanned instrument with carefully configured laser beam introduction and image-acquisition optics. Thus the new system not only has improved imaging capabilities, but allows micromanipulation and maintenance of tissues and organs.
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Affiliation(s)
- Milan Makale
- University of California, San Diego, Moores Cancer Center, 3855 Health Sciences Drive, La Jolla, California 92093, USA
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