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Prior R, Silva A, Vangansewinkel T, Idkowiak J, Tharkeshwar AK, Hellings TP, Michailidou I, Vreijling J, Loos M, Koopmans B, Vlek N, Agaser C, Kuipers TB, Michiels C, Rossaert E, Verschoren S, Vermeire W, de Laat V, Dehairs J, Eggermont K, van den Biggelaar D, Bademosi AT, Meunier FA, vandeVen M, Van Damme P, Mei H, Swinnen JV, Lambrichts I, Baas F, Fluiter K, Wolfs E, Van Den Bosch L. PMP22 duplication dysregulates lipid homeostasis and plasma membrane organization in developing human Schwann cells. Brain 2024:awae158. [PMID: 38743588 DOI: 10.1093/brain/awae158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 04/08/2024] [Accepted: 04/19/2024] [Indexed: 05/16/2024] Open
Abstract
Charcot-Marie-Tooth disease type 1A (CMT1A) is the most common inherited peripheral neuropathy caused by a 1.5 megabase tandem duplication of chromosome 17 harboring the PMP22 gene. This dose-dependent overexpression of PMP22 results in disrupted Schwann cell myelination of peripheral nerves. To get better insights into the underlying pathogenic mechanisms in CMT1A, we investigated the role of PMP22 duplication on cellular homeostasis in CMT1A mouse models and in patient-derived induced pluripotent stem cells differentiated into Schwann cell precursors (iPSC-SCPs). We performed lipidomic profiling and bulk RNA sequencing on sciatic nerves of two developing CMT1A mouse models and on CMT1A patient derived iPSC-SCPs. For the sciatic nerves of the CMT1A mice, cholesterol and lipid metabolism was dose-dependently downregulated throughout development. For the CMT1A iPSC-SCPs, transcriptional analysis unveiled a strong suppression of genes related to autophagy and lipid metabolism. Gene ontology enrichment analysis identified disturbances in pathways related to plasma membrane components and cell receptor signaling. Lipidomic analysis confirmed the severe dysregulation in plasma membrane lipids, particularly sphingolipids, in CMT1A iPSC-SCPs. Furthermore, we identified reduced lipid raft dynamics, disturbed plasma membrane fluidity, and impaired cholesterol incorporation and storage, all of which could result from altered lipid storage homeostasis in the patient-derived CMT1A iPSC-SCPs. Importantly, this phenotype could be rescued by stimulating autophagy and lipolysis. We conclude that PMP22 duplication disturbs intracellular lipid storage and leads to a more disordered plasma membrane due to an alteration in the lipid composition, which ultimately may lead to impaired axo-glial interactions. Moreover, targeting lipid handling and metabolism could hold promise for the treatment of CMT1A patients.
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Affiliation(s)
- Robert Prior
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
- Department of Ophthalmology, Medical Faculty, University of Bonn, 53127, Bonn, Germany
| | - Alessio Silva
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
| | - Tim Vangansewinkel
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
- UHasselt - Hasselt University, Biomedical Research Institute, 3590, Diepenbeek, Belgium
| | - Jakub Idkowiak
- Laboratory of Lipid Metabolism and Cancer, Department of Oncology, KU Leuven, 3000, Leuven, Belgium
- Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, 532 10, Pardubice, Czech Republic
| | - Arun Kumar Tharkeshwar
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
| | - Tom P Hellings
- Department of Clinical Genetics, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Iliana Michailidou
- Department of Clinical Genetics, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Jeroen Vreijling
- Department of Clinical Genetics, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Maarten Loos
- Sylics (Synaptologics BV), Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands
| | - Bastijn Koopmans
- Sylics (Synaptologics BV), Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands
| | - Nina Vlek
- Sylics (Synaptologics BV), Antonie van Leeuwenhoeklaan 9, 3721 MA, Bilthoven, The Netherlands
| | - Cedrick Agaser
- Department of Biomedical Data Sciences, Sequencing Analysis Support Core, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Thomas B Kuipers
- Department of Biomedical Data Sciences, Sequencing Analysis Support Core, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Christine Michiels
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
| | - Elisabeth Rossaert
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
| | - Stijn Verschoren
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
| | - Wendy Vermeire
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
| | - Vincent de Laat
- Laboratory of Lipid Metabolism and Cancer, Department of Oncology, KU Leuven, 3000, Leuven, Belgium
| | - Jonas Dehairs
- Laboratory of Lipid Metabolism and Cancer, Department of Oncology, KU Leuven, 3000, Leuven, Belgium
| | - Kristel Eggermont
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
| | - Diede van den Biggelaar
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
| | - Adekunle T Bademosi
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Frederic A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, 4072, Queensland, Australia
- School of Biomedical Sciences, The University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Martin vandeVen
- UHasselt - Hasselt University, Biomedical Research Institute, 3590, Diepenbeek, Belgium
| | - Philip Van Damme
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
- University Hospitals Leuven, Department of Neurology, 3000, Leuven, Belgium
| | - Hailiang Mei
- Department of Biomedical Data Sciences, Sequencing Analysis Support Core, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Johannes V Swinnen
- Laboratory of Lipid Metabolism and Cancer, Department of Oncology, KU Leuven, 3000, Leuven, Belgium
| | - Ivo Lambrichts
- UHasselt - Hasselt University, Biomedical Research Institute, 3590, Diepenbeek, Belgium
| | - Frank Baas
- Department of Clinical Genetics, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Kees Fluiter
- Department of Clinical Genetics, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Esther Wolfs
- UHasselt - Hasselt University, Biomedical Research Institute, 3590, Diepenbeek, Belgium
| | - Ludo Van Den Bosch
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000, Leuven, Belgium
- VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
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2
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Devoght J, Comhair J, Morelli G, Rigo JM, D'Hooge R, Touma C, Palme R, Dewachter I, vandeVen M, Harvey RJ, Schiffmann SN, Piccart E, Brône B. Dopamine-mediated striatal activity and function is enhanced in GlyRα2 knockout animals. iScience 2023; 26:107400. [PMID: 37554441 PMCID: PMC10404725 DOI: 10.1016/j.isci.2023.107400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 04/27/2023] [Accepted: 07/12/2023] [Indexed: 08/10/2023] Open
Abstract
The glycine receptor alpha 2 (GlyRα2) is a ligand-gated ion channel which upon activation induces a chloride conductance. Here, we investigated the role of GlyRα2 in dopamine-stimulated striatal cell activity and behavior. We show that depletion of GlyRα2 enhances dopamine-induced increases in the activity of putative dopamine D1 receptor-expressing striatal projection neurons, but does not alter midbrain dopamine neuron activity. We next show that the locomotor response to d-amphetamine is enhanced in GlyRα2 knockout animals, and that this increase correlates with c-fos expression in the dorsal striatum. 3-D modeling revealed an increase in the neuronal ensemble size in the striatum in response to D-amphetamine in GlyRα2 KO mice. Finally, we show enhanced appetitive conditioning in GlyRα2 KO animals that is likely due to increased motivation, but not changes in associative learning or hedonic response. Taken together, we show that GlyRα2 is an important regulator of dopamine-stimulated striatal activity and function.
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Affiliation(s)
- Jens Devoght
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
| | - Joris Comhair
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
| | - Giovanni Morelli
- Brain Development and Disease Laboratory, Instituto Italiano di Tecnologia, 16163 Genova, Italy
| | | | - Rudi D'Hooge
- Laboratory for Biological Psychology, University of Leuven, 3000 Leuven, Belgium
| | - Chadi Touma
- Department of Behavioural Biology, University of Osnabrück, 49076 Osnabrück, Germany
| | - Rupert Palme
- Institute of Biochemistry, University of Veterinary Medicine Vienna, Vienna A-1210, Austria
| | - Ilse Dewachter
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
| | | | - Robert J. Harvey
- School of Health, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Serge N. Schiffmann
- Laboratory of Neurophysiology, Université libre de Bruxelles, 1070 Brussels, Belgium
| | | | - Bert Brône
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
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3
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Slenders E, Bové H, Urbain M, Mugnier Y, Sonay AY, Pantazis P, Bonacina L, Vanden Berghe P, vandeVen M, Ameloot M. Image Correlation Spectroscopy with Second Harmonic Generating Nanoparticles in Suspension and in Cells. J Phys Chem Lett 2018; 9:6112-6118. [PMID: 30273489 DOI: 10.1021/acs.jpclett.8b02686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The absence of photobleaching, blinking, and saturation combined with a high contrast provides unique advantages of higher-harmonic generating nanoparticles over fluorescent probes, allowing for prolonged correlation spectroscopy studies. We apply the coherent intensity fluctuation model to study the mobility of second harmonic generating nanoparticles. A concise protocol is presented for quantifying the diffusion coefficient from a single spectroscopy measurement without the need for separate point-spread-function calibrations. The technique's applicability is illustrated on nominally 56 nm LiNbO3 nanoparticles. We perform label-free raster image correlation spectroscopy imaging in aqueous suspension and spatiotemporal image correlation spectroscopy in A549 human lung carcinoma cells. In good agreement with the expected theoretical result, the measured diffusion coefficient in water at room temperature is (7.5 ± 0.3) μm2/s. The diffusion coefficient in the cells is more than 103 times lower and heterogeneous, with an average of (3.7 ± 1.5) × 10-3 μm2/s.
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Affiliation(s)
- Eli Slenders
- Biomedical Research Institute (BIOMED) , Hasselt University , Agoralaan Bldg. C , 3590 Diepenbeek , Belgium
| | - Hannelore Bové
- Biomedical Research Institute (BIOMED) , Hasselt University , Agoralaan Bldg. C , 3590 Diepenbeek , Belgium
| | - Mathias Urbain
- Univ. Savoie Mont Blanc, SYMME , F-74000 Annecy , France
| | | | - Ali Yasin Sonay
- Department of Biosystems Science and Engineering , ETH Zürich , Mattenstrasse 26 , 4058 Basel , Switzerland
| | - Periklis Pantazis
- Department of Biosystems Science and Engineering , ETH Zürich , Mattenstrasse 26 , 4058 Basel , Switzerland
- Department of Bioengineering , Imperial College London , South Kensington Campus , London SW7 2AZ , U.K
| | - Luigi Bonacina
- Department of Applied Physics , Université de Genève , Chemin de Pinchat 22 , 1211 Geneva , Switzerland
| | - Pieter Vanden Berghe
- Laboratory for Enteric Neuroscience (LENS), TARGID , University of Leuven , Herestraat 49 , 3000 Leuven , Belgium
| | - Martin vandeVen
- Biomedical Research Institute (BIOMED) , Hasselt University , Agoralaan Bldg. C , 3590 Diepenbeek , Belgium
| | - Marcel Ameloot
- Biomedical Research Institute (BIOMED) , Hasselt University , Agoralaan Bldg. C , 3590 Diepenbeek , Belgium
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Steuwe C, Bové H, Clerinx J, vandeVen M, Fron E, Nawrot T, Ameloot M, Roeffaers M. Rapid and label-free optical detection of individual carbon air pollutant nanoparticulates in biomedical samples. J Biophotonics 2018; 11:e201700233. [PMID: 29265706 DOI: 10.1002/jbio.201700233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 12/17/2017] [Indexed: 05/23/2023]
Abstract
Carbonaceous particle exposure and air pollution in general lead to a multitude of adverse human health effects and pose multiple challenges in terms of exposure, risk and safety assessment. Highly desirable for fast screening are label-free approaches for detecting these particle types in biological or medical context. We report a powerful approach for detecting carbonaceous particles using photothermal pump-probe microscopy, which directly probes their strong light absorption. The principle and reliability of this approach is demonstrated by examining 4 different carbon black (CB) species modeling soot with diameters ranging from 13 to 500 nm. Our results show that the proposed approach is applicable to a large number of CB types as well as black carbon. As the particles show a strong absorption over a wide spectral range as compared to other absorbing species, we can image CB particles almost background free. Our pump-probe approach allows label-free optical detection and unambiguous localization of CB particles in (bio)fluids and 3D cellular environments. In combination with fluorescence microscopy, this method allows for simultaneous colocalization of CB with different cellular components using fluorophores as shown here for human lung fibroblasts. We further demonstrate the versatility of pump-probe detection in a flow cell.
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Affiliation(s)
- Christian Steuwe
- Centre for Surface Chemistry and Catalysis, KU Leuven, Leuven, Belgium
| | - Hannelore Bové
- Centre for Surface Chemistry and Catalysis, KU Leuven, Leuven, Belgium
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Jan Clerinx
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - Martin vandeVen
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Eduard Fron
- Department of Chemistry, Molecular Imaging and Photonics, KU Leuven, Leuven, Belgium
| | - Tim Nawrot
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
- Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium
| | - Marcel Ameloot
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Maarten Roeffaers
- Centre for Surface Chemistry and Catalysis, KU Leuven, Leuven, Belgium
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Slenders E, Seneca S, Pramanik SK, Smisdom N, Adriaensens P, vandeVen M, Ethirajan A, Ameloot M. Dynamics of the phospholipid shell of microbubbles: a fluorescence photoselection and spectral phasor approach. Chem Commun (Camb) 2018; 54:4854-4857. [DOI: 10.1039/c8cc01012a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The lipid organization of microbubbles is important in many applications.
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Affiliation(s)
- Eli Slenders
- Biomedical Research Institute (BIOMED)
- Hasselt University
- Agoralaan Bldg. C
- 3590 Diepenbeek
- Belgium
| | - Senne Seneca
- Institute for Materials Research (IMO)
- Hasselt University
- Wetenschapspark 1 and Agoralaan Bldg. D
- 3590 Diepenbeek
- Belgium
| | - Sumit Kumar Pramanik
- Institute for Materials Research (IMO)
- Hasselt University
- Wetenschapspark 1 and Agoralaan Bldg. D
- 3590 Diepenbeek
- Belgium
| | - Nick Smisdom
- Biomedical Research Institute (BIOMED)
- Hasselt University
- Agoralaan Bldg. C
- 3590 Diepenbeek
- Belgium
| | - Peter Adriaensens
- Institute for Materials Research (IMO)
- Hasselt University
- Wetenschapspark 1 and Agoralaan Bldg. D
- 3590 Diepenbeek
- Belgium
| | - Martin vandeVen
- Biomedical Research Institute (BIOMED)
- Hasselt University
- Agoralaan Bldg. C
- 3590 Diepenbeek
- Belgium
| | - Anitha Ethirajan
- Institute for Materials Research (IMO)
- Hasselt University
- Wetenschapspark 1 and Agoralaan Bldg. D
- 3590 Diepenbeek
- Belgium
| | - Marcel Ameloot
- Biomedical Research Institute (BIOMED)
- Hasselt University
- Agoralaan Bldg. C
- 3590 Diepenbeek
- Belgium
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Bové H, Steuwe C, Fron E, Slenders E, D'Haen J, Fujita Y, Uji-I H, vandeVen M, Roeffaers M, Ameloot M. Biocompatible Label-Free Detection of Carbon Black Particles by Femtosecond Pulsed Laser Microscopy. Nano Lett 2016; 16:3173-8. [PMID: 27104759 DOI: 10.1021/acs.nanolett.6b00502] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Although adverse health effects of carbon black (CB) exposure are generally accepted, a direct, label-free approach for detecting CB particles in fluids and at the cellular level is still lacking. Here, we report nonincandescence related white-light (WL) generation by dry and suspended carbon black particles under illumination with femtosecond (fs) pulsed near-infrared light as a powerful tool for the detection of these carbonaceous materials. This observation is done for four different CB species with diameters ranging from 13 to 500 nm, suggesting this WL emission under fs near-infrared illumination is a general property of CB particles. As the emitted radiation spreads over the whole visible spectrum, detection is straightforward and flexible. The unique property of the described WL emission allows optical detection and unequivocal localization of CB particles in fluids and in cellular environments while simultaneously colocalizing different cellular components using various specific fluorophores as shown here using human lung fibroblasts. The experiments are performed on a typical multiphoton laser-scanning microscopy platform, widely available in research laboratories.
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Affiliation(s)
- Hannelore Bové
- Biomedical Research Institute, Hasselt University , Agoralaan Building C, 3590 Diepenbeek, Belgium
| | | | | | - Eli Slenders
- Biomedical Research Institute, Hasselt University , Agoralaan Building C, 3590 Diepenbeek, Belgium
| | - Jan D'Haen
- Institute for Material Research, Hasselt University , Wetenschapspark 1, 3950 Diepenbeek, Belgium
| | | | - Hiroshi Uji-I
- Research Institute for Electronic Science, Hokkaido University , N20W10, Kita-Ward Sapporo 001-0020, Japan
| | - Martin vandeVen
- Biomedical Research Institute, Hasselt University , Agoralaan Building C, 3590 Diepenbeek, Belgium
| | | | - Marcel Ameloot
- Biomedical Research Institute, Hasselt University , Agoralaan Building C, 3590 Diepenbeek, Belgium
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7
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Slenders E, vandeVen M, Hooyberghs J, Ameloot M. Coherent intensity fluctuation model for autocorrelation imaging spectroscopy with higher harmonic generating point scatterers-a comprehensive theoretical study. Phys Chem Chem Phys 2015; 17:18937-43. [PMID: 26130478 DOI: 10.1039/c5cp02567b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We present a general analytical model for the intensity fluctuation autocorrelation function for second and third harmonic generating point scatterers. Expressions are derived for a stationary laser beam and for scanning beam configurations for specific correlation methodologies. We discuss free translational diffusion in both three and two dimensions. At low particle concentrations, the expressions for fluorescence are retrieved, while at high particle concentrations a rescaling of the function parameters is required for a stationary illumination beam, provided that the phase shift per unit length of the beam equals zero.
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Affiliation(s)
- Eli Slenders
- Biomed, Hasselt University, Agoralaan, Bldg C, B-3590 Diepenbeek, Belgium.
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8
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vandeVen M. Modeling Host - Bacterial Biofilm Interactions in Lower Leg Chronic Wounds. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.1712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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9
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Smisdom N, Braeckmans K, Deschout H, vandeVen M, Rigo JM, De Smedt SC, Ameloot M. Fluorescence recovery after photobleaching on the confocal laser-scanning microscope: generalized model without restriction on the size of the photobleached disk. J Biomed Opt 2011; 16:046021. [PMID: 21529089 DOI: 10.1117/1.3569620] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Fluorescence recovery after photobleaching (FRAP) carried out on a confocal laser-scanning microscope (CLSM) performs well for photobleached disks that are large compared to the resolution of the bleaching beam. For smaller disks approaching this resolution, current FRAP models providing a closed-form solution do not allow one to extract the diffusion coefficient accurately. The new generalized disk model we present addresses this shortcoming by bringing into account the bleaching resolution and the total confocal imaging resolution. A closed-form solution is obtained under the assumption of linear photobleaching. Furthermore, simultaneous analysis of FRAP data collected at various disk sizes allows for the intrinsic determination of the instrumental resolution parameters, thereby obviating the need for an extrinsic calibration. A new method to estimate the variance of FRAP data is introduced to allow for proper weighting in this global analysis approach by nonlinear least squares. Experiments are performed on two independent CLSMs on homogeneous samples providing validation over a large range of diffusion coefficients.
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Affiliation(s)
- Nick Smisdom
- Hasselt University, Transnational University Limburg, Biomedical Research Institute, School of Life Sciences, Agoralaan Building C, Diepenbeek 3590, Belgium
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10
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Smolders I, Smets I, Maier O, vandeVen M, Steels P, Ameloot M. Simvastatin interferes with process outgrowth and branching of oligodendrocytes. J Neurosci Res 2011; 88:3361-75. [PMID: 20857509 DOI: 10.1002/jnr.22490] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Statins have attracted interest as a treatment option for multiple sclerosis (MS) because of their pleiotropic antiinflammatory and immunomodulatory effects. However, contradictory results have been described when they are applied to oligodendrocytes (OLGs), the cell type predominantly affected in MS. In this study we focus on the in vitro effect of statins on process outgrowth in OLN-93 cells, a well-characterized OLG-derived cell line, and primary cultures of neonatal rat OLGs. Application of the lipophilic simvastatin, as low as 0.1-1 μM, disturbs process formation of both cell types, leading to less ramified cells. We show that both protein isoprenylation and cholesterol synthesis are required for the normal differentiation of OLGs. It is further demonstrated that the expression of 2',3'-cyclic-nucleotide-3' phosphodiesterase (CNP) and tubulin is lowered, concomitant with a reduction of membrane-bound CNP as well as tubulin. Therefore, we propose that lack of isoprenylation of CNP could help to explain the altered morphological and biochemical differentiation state of treated OLGs. Moreover, expression of specific myelin markers, such as myelin basic protein, myelin-associated glycoprotein, and myelin oligodendrocyte glycoprotein, was compromised after treatment. We conclude that simvastatin treatment has detrimental effects on OLG process outgrowth, the prior step in (re)myelination, thereby mortgaging long-term healing of MS lesions.
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Affiliation(s)
- Inge Smolders
- Biomedical Research Institute, School of Life Sciences, Hasselt University and Transnational University Limburg, Diepenbeek, Belgium
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11
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Abstract
Detailed practical information is provided with emphasis on mapping cytosolic and mitochondrial pH, mitochondrial Na(+), and briefly also aspects related to mitochondrial Ca(2+) measurements in living cells, as grown on (un)coated glass coverslips. This chapter lists (laser scanning confocal) microscope instrumentation and setup requirements for proper imaging conditions, cell holders, and an easy-to-use incubator stage. For the daily routine of preparing buffer and calibration solutions, extensive annotated protocols are provided. In addition, detailed measurement and image analysis protocols are given to routinely obtain optimum results with confidence, while avoiding a number of typical pitfalls.
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Affiliation(s)
- Martin vandeVen
- Cell Physiology Group, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
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12
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vandeVen M. Using Phasors in Interpreting One- and Two-Photon Fluorescence Lifetime Images of Fruit and Polymer Interfaces. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.2139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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13
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Gielen E, Smisdom N, vandeVen M, De Clercq B, Gratton E, Digman M, Rigo JM, Hofkens J, Engelborghs Y, Ameloot M. Measuring diffusion of lipid-like probes in artificial and natural membranes by raster image correlation spectroscopy (RICS): use of a commercial laser-scanning microscope with analog detection. Langmuir 2009; 25:5209-18. [PMID: 19260653 PMCID: PMC2728053 DOI: 10.1021/la8040538] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The heterogeneity in composition and interaction within the cellular membrane translates into a wide range of diffusion coefficients of its constituents. Therefore, several complementary microfluorimetric techniques such as fluorescence correlation spectroscopy (FCS), fluorescence recovery after photobleaching (FRAP) and single-particle tracking (SPT) have to be applied to explore the dynamics of membrane components. The recently introduced raster image correlation spectroscopy (RICS) offers a much wider dynamic range than each of these methods separately and allows for spatial mapping of the dynamic properties. RICS is implemented on a confocal laser-scanning microscope (CLSM), and the wide dynamic range is achieved by exploiting the inherent time information carried by the scanning laser beam in the generation of the confocal images. The original introduction of RICS used two-photon excitation and photon counting detection. However, most CLSM systems are based on one-photon excitation with analog detection. Here we report on the performance of such a commercial CLSM (Zeiss LSM 510 META) in the study of the diffusion of the fluorescent lipid analog 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indodicarbocyanine perchlorate (DiI-C(18)(5)) both in giant unilamellar vesicles and in the plasma membrane of living oligodendrocytes, i.e., the myelin-producing cells of the central nervous system. It is shown that RICS on a commercial CLSM with analog detection allows for reliable results in the study of membrane diffusion by removal of unwanted correlations introduced by the analog detection system. The results obtained compare well with those collected by FRAP and FCS.
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Affiliation(s)
- Ellen Gielen
- Laboratory for Cell Physiology, Biomedical Research Institute, Hasselt University and transnationale Universiteit Limburg, Agoralaan, Bldg C, B-3590 Diepenbeek, Belgium
- Laboratory for Biomolecular Dynamics, Katholieke Universiteit Leuven, Celestijnenlaan 200G, B-3001 Heverlee, Belgium
| | - Nick Smisdom
- Laboratory for Cell Physiology, Biomedical Research Institute, Hasselt University and transnationale Universiteit Limburg, Agoralaan, Bldg C, B-3590 Diepenbeek, Belgium
| | - Martin vandeVen
- Laboratory for Cell Physiology, Biomedical Research Institute, Hasselt University and transnationale Universiteit Limburg, Agoralaan, Bldg C, B-3590 Diepenbeek, Belgium
| | - Ben De Clercq
- Laboratory for Cell Physiology, Biomedical Research Institute, Hasselt University and transnationale Universiteit Limburg, Agoralaan, Bldg C, B-3590 Diepenbeek, Belgium
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, University of California, Biomedical Engineering Department, 3120 Natural Sciences 2, Irvine, CA 92697-2715, USA
| | - Michelle Digman
- Laboratory for Fluorescence Dynamics, University of California, Biomedical Engineering Department, 3120 Natural Sciences 2, Irvine, CA 92697-2715, USA
| | - Jean-Michel Rigo
- Laboratory for Cell Physiology, Biomedical Research Institute, Hasselt University and transnationale Universiteit Limburg, Agoralaan, Bldg C, B-3590 Diepenbeek, Belgium
| | - Johan Hofkens
- Laboratory for Photochemistry and Spectroscopy, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
| | - Yves Engelborghs
- Laboratory for Biomolecular Dynamics, Katholieke Universiteit Leuven, Celestijnenlaan 200G, B-3001 Heverlee, Belgium
| | - Marcel Ameloot
- Laboratory for Cell Physiology, Biomedical Research Institute, Hasselt University and transnationale Universiteit Limburg, Agoralaan, Bldg C, B-3590 Diepenbeek, Belgium
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vandeVen M, Gielen E, De Clercq B, Smisdom N, Ameloot M. Raster Image Correlation Spectroscopy (RICS) with One Photon Excitation and Analog Detection: Some Practical Considerations for GUVs and Cell Membranes. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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15
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Gielen E, vandeVen M, Margineanu A, Dedecker P, Auweraer MVD, Engelborghs Y, Hofkens J, Ameloot M. On the use of Z-scan fluorescence correlation experiments on giant unilamellar vesicles. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2008.12.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Wenmackers S, Pop SD, Roodenko K, Vermeeren V, Williams OA, Daenen M, Douhéret O, D'Haen J, Hardy A, Van Bael MK, Hinrichs K, Cobet C, vandeVen M, Ameloot M, Haenen K, Michiels L, Esser N, Wagner P. Structural and optical properties of DNA layers covalently attached to diamond surfaces. Langmuir 2008; 24:7269-7277. [PMID: 18558777 DOI: 10.1021/la800464p] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Label-free detection of DNA molecules on chemically vapor-deposited diamond surfaces is achieved with spectroscopic ellipsometry in the infrared and vacuum ultraviolet range. This nondestructive method has the potential to yield information on the average orientation of single as well as double-stranded DNA molecules, without restricting the strand length to the persistence length. The orientational analysis based on electronic excitations in combination with information from layer thicknesses provides a deeper understanding of biological layers on diamond. The pi-pi* transition dipole moments, corresponding to a transition at 4.74 eV, originate from the individual bases. They are in a plane perpendicular to the DNA backbone with an associated n-pi* transition at 4.47 eV. For 8-36 bases of single- and double-stranded DNA covalently attached to ultra-nanocrystalline diamond, the ratio between in- and out-of-plane components in the best fit simulations to the ellipsometric spectra yields an average tilt angle of the DNA backbone with respect to the surface plane ranging from 45 degrees to 52 degrees . We comment on the physical meaning of the calculated tilt angles. Additional information is gathered from atomic force microscopy, fluorescence imaging, and wetting experiments. The results reported here are of value in understanding and optimizing the performance of the electronic readout of a diamond-based label-free DNA hybridization sensor.
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Affiliation(s)
- Sylvia Wenmackers
- Hasselt University, Institute for Materials Research, Material Physics, and Inorganic and Physical Chemistry, Wetenschapspark 1, B-3590 Diepenbeek, Belgium
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Vermeeren V, Bijnens N, Wenmackers S, Daenen M, Haenen K, Williams OA, Ameloot M, vandeVen M, Wagner P, Michiels L. Towards a real-time, label-free, diamond-based DNA sensor. Langmuir 2007; 23:13193-13202. [PMID: 18004892 DOI: 10.1021/la702143d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Most challenging in the development of DNA sensors is the ability to distinguish between fully complementary target ssDNA (single-strand DNA) and 1-mismatch ssDNA. To deal with this problem, we performed impedance spectroscopy on DNA-functionalized nanocrystalline diamond (NCD) layers during hybridization and denaturation. In both reactions, a difference in behavior was observed for 1-mismatch target DNA and complementary target DNA in real-time. During real-time hybridization, a decrease of the impedance was observed at lower frequencies when the complementary target DNA was added, while the addition of 1-mismatch target ssDNA caused no significant change. Fitting these results to an electrical circuit demonstrates that this is correlated with a decrease of the depletion zone in the space charge region of the diamond. During real-time denaturation, differentiation between 1-mismatch and complementary target DNA was possible at higher frequencies. Denaturation of complementary DNA showed the longest exponential decay time of the impedance, while the decay time during 1-mismatch denaturation was the shortest. The real-time hybridization and denaturation experiments were carried out on different NCD samples in various buffer solutions at temperatures between 20 and 80 degrees C. It was revealed that the best results were obtained using a Microhyb hybridization buffer at 80 degrees C and 10x PCR buffer at 30 degrees C for hybridization and 0.1 M NaOH at temperatures above 40 degrees C for denaturation. We demonstrate that the combination of real-time hybridization spectra and real-time denaturation spectra yield important information on the type of target. This approach may allow a reliable identification of the mismatch sequence, which is the most biologically relevant.
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Affiliation(s)
- V Vermeeren
- Hasselt University and Transnationale Universiteit Limburg, School for Life Sciences, Biomedical Research Institute, Agoralaan, Building A, B-3590 Diepenbeek, Belgium
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18
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Boens N, Qin W, Basarić N, Hofkens J, Ameloot M, Pouget J, Lefévre JP, Valeur B, Gratton E, vandeVen M, Silva ND, Engelborghs Y, Willaert K, Sillen A, Rumbles G, Phillips D, Visser AJWG, van Hoek A, Lakowicz JR, Malak H, Gryczynski I, Szabo AG, Krajcarski DT, Tamai N, Miura A. Fluorescence lifetime standards for time and frequency domain fluorescence spectroscopy. Anal Chem 2007; 79:2137-49. [PMID: 17269654 PMCID: PMC6816264 DOI: 10.1021/ac062160k] [Citation(s) in RCA: 267] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of fluorophores with single-exponential fluorescence decays in liquid solution at 20 degrees C were measured independently by nine laboratories using single-photon timing and multifrequency phase and modulation fluorometry instruments with lasers as excitation source. The dyes that can serve as fluorescence lifetime standards for time-domain and frequency-domain measurements are all commercially available, are photostable under the conditions of the measurements, and are soluble in solvents of spectroscopic quality (methanol, cyclohexane, water). These lifetime standards are anthracene, 9-cyanoanthracene, 9,10-diphenylanthracene, N-methylcarbazole, coumarin 153, erythrosin B, N-acetyl-l-tryptophanamide, 1,4-bis(5-phenyloxazol-2-yl)benzene, 2,5-diphenyloxazole, rhodamine B, rubrene, N-(3-sulfopropyl)acridinium, and 1,4-diphenylbenzene. At 20 degrees C, the fluorescence lifetimes vary from 89 ps to 31.2 ns, depending on fluorescent dye and solvent, which is a useful range for modern pico- and nanosecond time-domain or mega- to gigahertz frequency-domain instrumentation. The decay times are independent of the excitation and emission wavelengths. Dependent on the structure of the dye and the solvent, the excitation wavelengths used range from 284 to 575 nm, the emission from 330 to 630 nm. These lifetime standards may be used to either calibrate or test the resolution of time- and frequency-domain instrumentation or as reference compounds to eliminate the color effect in photomultiplier tubes. Statistical analyses by means of two-sample charts indicate that there is no laboratory bias in the lifetime determinations. Moreover, statistical tests show that there is an excellent correlation between the lifetimes estimated by the time-domain and frequency-domain fluorometries. Comprehensive tables compiling the results for 20 (fluorescence lifetime standard/solvent) combinations are given.
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Affiliation(s)
- Noël Boens
- To whom correspondence should be addressed. . Fax: +32-16-327 990. . Fax: + 32-11-268 599
| | | | | | | | - Marcel Ameloot
- To whom correspondence should be addressed. . Fax: +32-16-327 990. . Fax: + 32-11-268 599
| | | | - Jean-Pierre Lefévre
- CNRS UMR 8531, Laboratoire de Chimie Générale, CNAM, 292 rue Saint-Martin, F-75141 Paris Cedex 03, and Laboratoire PPSM, ENS-Cachan, 61 avenue du Président Wilson, 94235 Cachan Cedex, France
| | - Bernard Valeur
- CNRS UMR 8531, Laboratoire de Chimie Générale, CNAM, 292 rue Saint-Martin, F-75141 Paris Cedex 03, and Laboratoire PPSM, ENS-Cachan, 61 avenue du Président Wilson, 94235 Cachan Cedex, France
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, University of California, Biomedical Engineering Department, 3120 Natural Sciences II Building, Irvine, California 92697-2715
| | | | - Norberto D. Silva
- Laboratory for Fluorescence Dynamics, University of California, Biomedical Engineering Department, 3120 Natural Sciences II Building, Irvine, California 92697-2715
| | - Yves Engelborghs
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200G, 3001 Heverlee, Belgium
| | - Katrien Willaert
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200G, 3001 Heverlee, Belgium
| | - Alain Sillen
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200G, 3001 Heverlee, Belgium
| | - Garry Rumbles
- Department of Chemistry and Centre for Photomolecular Science, Imperial College, Exhibition Road, London SW7 2AY, United Kingdom
| | - David Phillips
- Department of Chemistry and Centre for Photomolecular Science, Imperial College, Exhibition Road, London SW7 2AY, United Kingdom
| | - Antonie J. W. G. Visser
- Departments of Biochemistry and Biophysics, MicroSpectroscopy Centre, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen The Netherlands
| | - Arie van Hoek
- Departments of Biochemistry and Biophysics, MicroSpectroscopy Centre, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen The Netherlands
| | - Joseph R. Lakowicz
- Center for Fluorescence Spectroscopy, Department of Biological Chemistry, University of Maryland, 660 W. Redwood Street, Baltimore Maryland 21201
| | - Henryk Malak
- Center for Fluorescence Spectroscopy, Department of Biological Chemistry, University of Maryland, 660 W. Redwood Street, Baltimore Maryland 21201
| | - Ignacy Gryczynski
- Center for Fluorescence Spectroscopy, Department of Biological Chemistry, University of Maryland, 660 W. Redwood Street, Baltimore Maryland 21201
| | - Arthur G. Szabo
- Faculty of Science, Wilfrid Laurier University, 75 University Avenue, Waterloo, Ontario N2L 3C5, Canada
| | - Don T. Krajcarski
- Faculty of Science, Wilfrid Laurier University, 75 University Avenue, Waterloo, Ontario N2L 3C5, Canada
| | | | - Atsushi Miura
- Department of Chemistry, School of Science, Kwansei Gakuin University, Uegahara1-1-155, Nishinomiya 662-8501, Japan
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Acasandrei MA, Dale RE, vandeVen M, Ameloot M. Two-dimensional Förster resonance energy transfer (2-D FRET) and the membrane raft hypothesis. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2005.11.104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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20
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Christiaens P, Vermeeren V, Wenmackers S, Daenen M, Haenen K, Nesládek M, vandeVen M, Ameloot M, Michiels L, Wagner P. EDC-mediated DNA attachment to nanocrystalline CVD diamond films. Biosens Bioelectron 2006; 22:170-7. [PMID: 16442276 DOI: 10.1016/j.bios.2005.12.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Revised: 11/04/2005] [Accepted: 12/14/2005] [Indexed: 11/27/2022]
Abstract
Chemical vapour deposited (CVD) diamond is a very promising material for biosensor fabrication owing both to its chemical inertness and the ability to make it electrical semiconducting that allows for connection with integrated circuits. For biosensor construction, a biochemical method to immobilize nucleic acids to a diamond surface has been developed. Nanocrystalline diamond is grown using microwave plasma-enhanced chemical vapour deposition (MPECVD). After hydrogenation of the surface, 10-undecenoic acid, an omega-unsaturated fatty acid, is tethered by 254 nm photochemical attachment. This is followed by 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide (EDC)-mediated attachment of amino (NH(2))-modified dsDNA. The functionality of the covalently bound dsDNA molecules is confirmed by fluorescence measurements, PCR and gel electrophoresis during 35 denaturation and rehybridisation steps. The linking method after the fatty acid attachment can easily be applied to other biomolecules like antibodies and enzymes.
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Affiliation(s)
- P Christiaens
- Hasselt University, Institute for Materials Research and Transnationale Universiteit Limburg, School for Life Sciences, Wetenschapspark 1, B-3590 Diepenbeek, Belgium.
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vandeVen M, Ameloot M, Valeur B, Boens N. Pitfalls and Their Remedies in Time-Resolved Fluorescence Spectroscopy and Microscopy. J Fluoresc 2005; 15:377-413. [PMID: 15986159 DOI: 10.1007/s10895-005-2632-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2004] [Accepted: 01/11/2005] [Indexed: 11/28/2022]
Abstract
Time-resolved fluorescence spectroscopy and microscopy in both time and frequency domains provide very useful and accurate information on dynamic processes. Good quality data are essential in obtaining reliable parameter estimates. Distortions of the fluorescence response due to artifacts may have disastrous consequences. We provide here a concise overview of potential difficulties encountered under daily laboratory circumstances in the use of time- and frequency-domain equipment as well as practical remedies against common error conditions, elucidated with several graphs to aid the researcher in visual inspection and quality-control of collected data. A range of artifacts due to sample preparation or to optical and electronic pitfalls are discussed, as are remedies against them. Also recommended data analysis strategies are described.
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Affiliation(s)
- Martin vandeVen
- Biomedisch Onderzoeksinstituut, Limburgs Universitair Centrum, School of Life Sciences, Transnationale Universiteit Limburg, 3590 Diepenbeek, Belgium
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Cooreman P, Thoelen R, Manca J, vandeVen M, Vermeeren V, Michiels L, Ameloot M, Wagner P. Impedimetric immunosensors based on the conjugated polymer PPV. Biosens Bioelectron 2005; 20:2151-6. [PMID: 15741090 DOI: 10.1016/j.bios.2004.08.029] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2004] [Revised: 08/04/2004] [Accepted: 08/18/2004] [Indexed: 11/30/2022]
Abstract
In the work reported here, we investigated the interaction between the semiconducting polymer MDMO-PPV and antibodies against the fluorescent dyes fluorescein isothiocyanate (FITC) and Cy5. The antibodies are adsorbed physically onto thin polymer films on gold electrodes, as seen in AFM images of these films. By tuning the antibody concentration, the contact angle of distilled water with the film can be made to vary between 95 degrees and 50 degrees, showing that different surface densities of antibody can be obtained. That these biosensor films specifically bind their antigenic fluorescent molecules from PBS buffer solution is demonstrated by confocal fluorescence microscopy. Specific antigen-antibody recognition is demonstrated by lack of cross-sensitivity between the two antibodies and their antigens. In a biosensor prototype based on differential impedance spectroscopy, these polymer films show a clear response to 1 ppb antigen solution, with a time constant of 2-3 min.
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Affiliation(s)
- P Cooreman
- Institute for Materials Research, Limburgs Universitair Centrum, Wetenschapspark 1, B-3590 Diepenbeek, Belgium.
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