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Doss BL, Konkol JA, Liu Y, Brinzari TV, Pan L. Correlative Atomic Force Microscopy and Raman Spectroscopy in Acid Erosion of Dentin. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1755-1763. [PMID: 37639376 DOI: 10.1093/micmic/ozad094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 07/21/2023] [Accepted: 08/07/2023] [Indexed: 08/31/2023]
Abstract
Physical properties and chemical composition are fundamentally defining and interconnected surface characteristics. However, few techniques are able to capture both in a correlative fashion at the same sample location and orientation. This is especially important for complex materials such as dentin, which is an inner tooth structure and is a heterogeneous, composite inorganic-organic material with open channels (tubules) that extend toward the tooth pulp. Here, a combined microscope system consisting of an atomic force microscope and a confocal Raman spectrometer was used to study the correlative physical and chemical properties of human dentin. The local hardness of dentin was highly correlated with the Raman signal ratio of inorganic to organic material, and this was enhanced in the peritubular regions of dentin. When the samples were etched with citric acid, Young's modulus, hardness, and inorganic-to-organic material ratio decreased significantly, collagen fibrils on the surface were exposed, the peritubular regions were removed, and the tubule diameters increased. Thus, the combined atomic force microscopy (AFM)-Raman approach allows for comprehensive and correlative physical-chemical analysis of material surfaces and will be invaluable for evaluating oral therapeutic strategies.
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Affiliation(s)
- Bryant L Doss
- Colgate-Palmolive Technology Center, 909 River Rd, Piscataway, NJ 08854, USA
| | - Jakub A Konkol
- Colgate-Palmolive Technology Center, 909 River Rd, Piscataway, NJ 08854, USA
- Department of Chemical and Biochemical Engineering, Rutgers University, 98 Brett Rd, Piscataway, NJ 08854, USA
| | - Yangxi Liu
- Colgate-Palmolive Technology Center, 909 River Rd, Piscataway, NJ 08854, USA
| | - Tatiana V Brinzari
- Colgate-Palmolive Technology Center, 909 River Rd, Piscataway, NJ 08854, USA
| | - Long Pan
- Colgate-Palmolive Technology Center, 909 River Rd, Piscataway, NJ 08854, USA
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2
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Zhao B, Mertz J. Resolution enhancement with deblurring by pixel reassignment (DPR). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.550382. [PMID: 37546886 PMCID: PMC10402078 DOI: 10.1101/2023.07.24.550382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Improving the spatial resolution of a fluorescence microscope has been an ongoing challenge in the imaging community. To address this challenge, a variety of approaches have been taken, ranging from instrumentation development to image post-processing. An example of the latter is deconvolution, where images are numerically deblurred based on a knowledge of the microscope point spread function. However, deconvolution can easily lead to noise-amplification artifacts. Deblurring by post-processing can also lead to negativities or fail to conserve local linearity between sample and image. We describe here a simple image deblurring algorithm based on pixel reassignment that inherently avoids such artifacts and can be applied to general microscope modalities and fluorophore types. Our algorithm helps distinguish nearby fluorophores even when these are separated by distances smaller than the conventional resolution limit, helping facilitate, for example, the application of single-molecule localization microscopy in dense samples. We demonstrate the versatility and performance of our algorithm under a variety of imaging conditions.
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Affiliation(s)
- Bingying Zhao
- Department of Electrical and Computer Engineering, Boston University, MA 02215
| | - Jerome Mertz
- Department of Biomedical Engineering, Boston University, MA 02215
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3
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Schmidt P, Lajoie J, Sivasankar S. Robust scan synchronized force-fluorescence imaging. Ultramicroscopy 2020; 221:113165. [PMID: 33352414 DOI: 10.1016/j.ultramic.2020.113165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/24/2020] [Accepted: 10/15/2020] [Indexed: 11/18/2022]
Abstract
Simultaneous atomic force microscope (AFM) and sample scanning confocal fluorescence microscope measurements are widely used to obtain mechanistic and structural insights into protein dynamics in live cells. However, the absence of a robust technique to synchronously scan both AFM and confocal microscope piezo stages makes it difficult to visualize force-induced changes in fluorescent protein distribution in cells. To address this challenge, we have built an integrated AFM-confocal fluorescence microscope platform that implements a synchronous scanning method which eliminates image artifacts from piezo motion ramping, produces accurate pixel binning and enables the collection of a scanned image of a sample while applying force to a single point on the sample. As proof of principle, we use this instrument to monitor the redistribution of fluorescent E-cadherin, an essential transmembrane protein, in live cells, upon application of mechanical force.
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Affiliation(s)
- Patrick Schmidt
- Department of Biomedical Engineering, University of California, Davis, CA, 95616, USA; Department of Electrical and Computer Engineering, Iowa State University, Ames, IA, 50011, USA
| | - John Lajoie
- Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011, USA
| | - Sanjeevi Sivasankar
- Department of Biomedical Engineering, University of California, Davis, CA, 95616, USA.
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Raab M, Jusuk I, Molle J, Buhr E, Bodermann B, Bergmann D, Bosse H, Tinnefeld P. Using DNA origami nanorulers as traceable distance measurement standards and nanoscopic benchmark structures. Sci Rep 2018; 8:1780. [PMID: 29379061 PMCID: PMC5789094 DOI: 10.1038/s41598-018-19905-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/21/2017] [Indexed: 11/09/2022] Open
Abstract
In recent years, DNA origami nanorulers for superresolution (SR) fluorescence microscopy have been developed from fundamental proof-of-principle experiments to commercially available test structures. The self-assembled nanostructures allow placing a defined number of fluorescent dye molecules in defined geometries in the nanometer range. Besides the unprecedented control over matter on the nanoscale, robust DNA origami nanorulers are reproducibly obtained in high yields. The distances between their fluorescent marks can be easily analysed yielding intermark distance histograms from many identical structures. Thus, DNA origami nanorulers have become excellent reference and training structures for superresolution microscopy. In this work, we go one step further and develop a calibration process for the measured distances between the fluorescent marks on DNA origami nanorulers. The superresolution technique DNA-PAINT is used to achieve nanometrological traceability of nanoruler distances following the guide to the expression of uncertainty in measurement (GUM). We further show two examples how these nanorulers are used to evaluate the performance of TIRF microscopes that are capable of single-molecule localization microscopy (SMLM).
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Affiliation(s)
- Mario Raab
- Institute for Physical & Theoretical Chemistry, and Braunschweig, Integrated Centre of Systems Biology (BRICS) and Laboratory for Emerging Nanometrology (LENA), Braunschweig University of Technology, Rebenring 56, 38106, Braunschweig, Germany.,Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universitaet Muenchen, Butenandtstr, 5-13, 81377, Muenchen, Germany
| | - Ija Jusuk
- Institute for Physical & Theoretical Chemistry, and Braunschweig, Integrated Centre of Systems Biology (BRICS) and Laboratory for Emerging Nanometrology (LENA), Braunschweig University of Technology, Rebenring 56, 38106, Braunschweig, Germany.,Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universitaet Muenchen, Butenandtstr, 5-13, 81377, Muenchen, Germany
| | - Julia Molle
- Institute for Physical & Theoretical Chemistry, and Braunschweig, Integrated Centre of Systems Biology (BRICS) and Laboratory for Emerging Nanometrology (LENA), Braunschweig University of Technology, Rebenring 56, 38106, Braunschweig, Germany
| | - Egbert Buhr
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - Bernd Bodermann
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - Detlef Bergmann
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - Harald Bosse
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - Philip Tinnefeld
- Institute for Physical & Theoretical Chemistry, and Braunschweig, Integrated Centre of Systems Biology (BRICS) and Laboratory for Emerging Nanometrology (LENA), Braunschweig University of Technology, Rebenring 56, 38106, Braunschweig, Germany. .,Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universitaet Muenchen, Butenandtstr, 5-13, 81377, Muenchen, Germany.
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Frederickx W, Rocha S, Fujita Y, Kennes K, De Keersmaecker H, De Feyter S, Uji-I H, Vanderlinden W. Orthogonal Probing of Single-Molecule Heterogeneity by Correlative Fluorescence and Force Microscopy. ACS NANO 2018; 12:168-177. [PMID: 29257876 DOI: 10.1021/acsnano.7b05405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Correlative imaging by fluorescence and force microscopy is an emerging technology to acquire orthogonal information at the nanoscale. Whereas atomic force microscopy excels at resolving the envelope structure of nanoscale specimens, fluorescence microscopy can detect specific molecular labels, which enables the unambiguous recognition of molecules in a complex assembly. Whereas correlative imaging at the micrometer scale has been established, it remains challenging to push the technology to the single-molecule level. Here, we used an integrated setup to systematically evaluate the factors that influence the quality of correlative fluorescence and force microscopy. Optimized data processing to ensure accurate drift correction and high localization precision results in image registration accuracies of ∼25 nm on organic fluorophores, which represents a 2-fold improvement over the state of the art in correlative fluorescence and force microscopy. Furthermore, we could extend the Atto532 fluorophore bleaching time ∼2-fold, by chemical modification of the supporting mica surface. In turn, this enables probing the composition of macromolecular complexes by stepwise photobleaching with high confidence. We demonstrate the performance of our method by resolving the stoichiometry of molecular subpopulations in a heterogeneous EcoRV-DNA nucleoprotein ensemble.
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Affiliation(s)
- Wout Frederickx
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven-University of Leuven , Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Susana Rocha
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven-University of Leuven , Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Yasuhiko Fujita
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven-University of Leuven , Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Koen Kennes
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven-University of Leuven , Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Herlinde De Keersmaecker
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven-University of Leuven , Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Steven De Feyter
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven-University of Leuven , Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - Hiroshi Uji-I
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven-University of Leuven , Celestijnenlaan 200F, B-3001, Leuven, Belgium
- Research Institute for Electronic Science, Nanomaterials and Nanoscopy, Hokkaido University , Kita 10 Nishi 20, North Ward, Sapporo 001-0020, Japan
| | - Willem Vanderlinden
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven-University of Leuven , Celestijnenlaan 200F, B-3001, Leuven, Belgium
- Department of Physics, Nanosystems Initiative Munich, and Center for NanoScience, LMU Munich , Amalienstrasse 54, 80799 Munich, Germany
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6
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Stanciu SG, Tranca DE, Hristu R, Stanciu GA. Correlative imaging of biological tissues with apertureless scanning near-field optical microscopy and confocal laser scanning microscopy. BIOMEDICAL OPTICS EXPRESS 2017; 8:5374-5383. [PMID: 29296474 PMCID: PMC5745089 DOI: 10.1364/boe.8.005374] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/01/2017] [Accepted: 11/01/2017] [Indexed: 05/27/2023]
Abstract
Apertureless scanning near-field optical microscopy (ASNOM) has attracted considerable interest over the past years as a result of its valuable contrast mechanisms and capabilities for optical resolutions in the nanoscale range. However, at this moment the intersections between ASNOM and the realm of bioimaging are scarce, mainly due to data interpretation difficulties linked to the limited body of work performed so far in this field and hence the reduced volume of supporting information. We propose an imaging approach that holds significant potential for alleviating this issue, consisting of correlative imaging of biological specimens using a multimodal system that incorporates ASNOM and confocal laser scanning microscopy (CLSM), which allows placing near-field data into a well understood context of anatomical relevance. We demonstrate this approach on zebrafish retinal tissue. The proposed method holds important implications for the in-depth understanding of biological items through the prism of ASNOM and CLSM data complementarity.
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Affiliation(s)
- Stefan G. Stanciu
- Center for Microscopy-Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, 060042, Romania
| | - Denis E. Tranca
- Center for Microscopy-Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, 060042, Romania
| | - Radu Hristu
- Center for Microscopy-Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, 060042, Romania
| | - George A. Stanciu
- Center for Microscopy-Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, 060042, Romania
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7
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Fischer T, Stöttinger S, Hinze G, Bottin A, Hu N, Basché T. Single Semiconductor Nanocrystals under Compressive Stress: Reversible Tuning of the Emission Energy. NANO LETTERS 2017; 17:1559-1563. [PMID: 28151680 DOI: 10.1021/acs.nanolett.6b04689] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The photoluminescence of individual CdSe/CdS/ZnS core/shell nanocrystals has been investigated under external forces. After mutual alignment of a correlative atomic force and confocal microscope, individual particles were colocalized and exposed to a series of force cycles by using the tip of the AFM cantilever as a nanoscale piston. Thus, force-dependent changes of photophysical properties could be tracked on a single particle level. Remarkably, individual nanocrystals either shifted to higher or to lower emission energies with no indications of multiple emission lines under applied force. The direction and magnitude of these reversible spectral shifts depend on the orientation of nanocrystal axes relative to the external anisotropic force. Maximum pressures derived from the applied forces within a simple contact-mechanical model lie in the GPa range, comparable to values typically emerging in diamond anvil cells. Average spectral shift parameters of -3.5 meV/GPa and 3.0 meV/GPa are found for red- and blue-shifting species, respectively. Our results clearly demonstrate that the emission energy of single nanocrystals can be reversibly tuned over an appreciable wavelength range without degradation of their performance which appears as a promising feature with respect to tunable single photon sources or the creation of coherently coupled particle dimers.
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Affiliation(s)
- Tobias Fischer
- Institute of Physical Chemistry, Johannes Gutenberg-University , Duesbergweg 10-14, 55128 Mainz, Germany
| | - Sven Stöttinger
- Institute of Physical Chemistry, Johannes Gutenberg-University , Duesbergweg 10-14, 55128 Mainz, Germany
| | - Gerald Hinze
- Institute of Physical Chemistry, Johannes Gutenberg-University , Duesbergweg 10-14, 55128 Mainz, Germany
| | - Anne Bottin
- Institute of Physical Chemistry, Johannes Gutenberg-University , Duesbergweg 10-14, 55128 Mainz, Germany
| | - Nan Hu
- Institute of Physical Chemistry, Johannes Gutenberg-University , Duesbergweg 10-14, 55128 Mainz, Germany
| | - Thomas Basché
- Institute of Physical Chemistry, Johannes Gutenberg-University , Duesbergweg 10-14, 55128 Mainz, Germany
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8
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Handschuh-Wang S, Wang T, Zhou X. Recent advances in hybrid measurement methods based on atomic force microscopy and surface sensitive measurement techniques. RSC Adv 2017. [DOI: 10.1039/c7ra08515j] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
This review summaries the recent progress of the combination of optical and non-optical surface sensitive techniques with the atomic force microscopy.
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Affiliation(s)
- Stephan Handschuh-Wang
- College of Chemistry and Environmental Engineering
- Shenzhen University
- Shenzhen 518060
- P. R. China
| | - Tao Wang
- Functional Thin Films Research Center
- Shenzhen Institutes of Advanced Technology
- Chinese Academy of Sciences
- Shenzhen 518055
- P. R. China
| | - Xuechang Zhou
- College of Chemistry and Environmental Engineering
- Shenzhen University
- Shenzhen 518060
- P. R. China
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9
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Staunton JR, Doss BL, Lindsay S, Ros R. Correlating confocal microscopy and atomic force indentation reveals metastatic cancer cells stiffen during invasion into collagen I matrices. Sci Rep 2016; 6:19686. [PMID: 26813872 PMCID: PMC4728602 DOI: 10.1038/srep19686] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 12/16/2015] [Indexed: 01/21/2023] Open
Abstract
Mechanical interactions between cells and their microenvironment dictate cell phenotype and behavior, calling for cell mechanics measurements in three-dimensional (3D) extracellular matrices (ECM). Here we describe a novel technique for quantitative mechanical characterization of soft, heterogeneous samples in 3D. The technique is based on the integration of atomic force microscopy (AFM) based deep indentation, confocal fluorescence microscopy, finite element (FE) simulations and analytical modeling. With this method, the force response of a cell embedded in 3D ECM can be decoupled from that of its surroundings, enabling quantitative determination of the elastic properties of both the cell and the matrix. We applied the technique to the quantification of the elastic properties of metastatic breast adenocarcinoma cells invading into collagen hydrogels. We found that actively invading and fully embedded cells are significantly stiffer than cells remaining on top of the collagen, a clear example of phenotypical change in response to the 3D environment. Treatment with Rho-associated protein kinase (ROCK) inhibitor significantly reduces this stiffening, indicating that actomyosin contractility plays a major role in the initial steps of metastatic invasion.
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Affiliation(s)
- Jack R. Staunton
- Department of Physics, Arizona State University, Tempe, AZ 85287
- Center for Biological Physics, Arizona State University, Tempe, AZ 85287
| | - Bryant L. Doss
- Department of Physics, Arizona State University, Tempe, AZ 85287
- Center for Biological Physics, Arizona State University, Tempe, AZ 85287
| | - Stuart Lindsay
- Department of Physics, Arizona State University, Tempe, AZ 85287
- Center for Biological Physics, Arizona State University, Tempe, AZ 85287
- Biodesign Institute, Arizona State University, Tempe, AZ 85287
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287
| | - Robert Ros
- Department of Physics, Arizona State University, Tempe, AZ 85287
- Center for Biological Physics, Arizona State University, Tempe, AZ 85287
- Biodesign Institute, Arizona State University, Tempe, AZ 85287
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11
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Raab M, Schmied JJ, Jusuk I, Forthmann C, Tinnefeld P. Fluorescence microscopy with 6 nm resolution on DNA origami. Chemphyschem 2014; 15:2431-5. [PMID: 24895173 DOI: 10.1002/cphc.201402179] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Indexed: 11/10/2022]
Abstract
Resolution of emerging superresolution microscopy is commonly characterized by the width of a point-spread-function or by the localization accuracy of single molecules. In contrast, resolution is defined as the ability to separate two objects. Recently, DNA origamis have been proven as valuable scaffold for self-assembled nanorulers in superresolution microscopy. Here, we use DNA origami nanorulers to overcome the discrepancy of localizing single objects and separating two objects by resolving two docking sites at distances of 18, 12, and 6 nm by using the superresolution technique DNA PAINT(point accumulation for imaging in nanoscale topography). For the smallest distances, we reveal the influence of localization noise on the yield of resolvable structures that we rationalize by Monte Carlo simulations.
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Affiliation(s)
- Mario Raab
- Institute for Physical and Theoretical Chemistry and Braunschweig Integrated Centre of Systems Biology (BRICS), Braunschweig University of Technology, Hans-Sommer Str. 10, 38106 Braunschweig (Germany)
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12
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Abstract
Validating and testing a fluorescence microscope or a microscopy method requires defined samples that can be used as standards. DNA origami is a new tool that provides a framework to place defined numbers of small molecules such as fluorescent dyes or proteins in a programmed geometry with nanometer precision. The flexibility and versatility in the design of DNA origami microscopy standards makes them ideally suited for the broad variety of emerging super-resolution microscopy methods. As DNA origami structures are durable and portable, they can become a universally available specimen to check the everyday functionality of a microscope. The standards are immobilized on a glass slide, and they can be imaged without further preparation and can be stored for up to 6 months. We describe a detailed protocol for the design, production and use of DNA origami microscopy standards, and we introduce a DNA origami rectangle, bundles and a nanopillar as fluorescent nanoscopic rulers. The protocol provides procedures for the design and realization of fluorescent marks on DNA origami structures, their production and purification, quality control, handling, immobilization, measurement and data analysis. The procedure can be completed in 1-2 d.
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Karedla N, Chizhik AI, Gregor I, Chizhik AM, Schulz O, Enderlein J. Single-molecule metal-induced energy transfer (smMIET): resolving nanometer distances at the single-molecule level. Chemphyschem 2014; 15:705-11. [PMID: 24478241 DOI: 10.1002/cphc.201300760] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 12/07/2013] [Indexed: 11/08/2022]
Abstract
We present a new concept for measuring distance values of single molecules from a surface with nanometer accuracy using the energy transfer from the excited molecule to surface plasmons of a metal film. We measure the fluorescence lifetime of individual dye molecules deposited on a dielectric spacer as a function of a spacer thickness. By using our theoretical model, we convert the lifetime values into the axial distance of individual molecules. Similar to Förster resonance energy transfer (FRET), this allows emitters to be localized with nanometer accuracy, but in contrast to FRET the distance range at which efficient energy transfer takes place is an order of magnitude larger. Our technique can be potentially used as a tool for measuring intramolecular distances of biomolecules and complexes.
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Affiliation(s)
- Narain Karedla
- Georg-August-Universität, III. Institute of Physics-Biophysics, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany), Fax: (+49) 551-39 7720
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14
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Resolution doubling in fluorescence microscopy with confocal spinning-disk image scanning microscopy. Proc Natl Acad Sci U S A 2013; 110:21000-5. [PMID: 24324140 DOI: 10.1073/pnas.1315858110] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We demonstrate how a conventional confocal spinning-disk (CSD) microscope can be converted into a doubly resolving image scanning microscopy (ISM) system without changing any part of its optical or mechanical elements. Making use of the intrinsic properties of a CSD microscope, we illuminate stroboscopically, generating an array of excitation foci that are moved across the sample by varying the phase between stroboscopic excitation and rotation of the spinning disk. ISM then generates an image with nearly doubled resolution. Using conventional fluorophores, we have imaged single nuclear pore complexes in the nuclear membrane and aggregates of GFP-conjugated Tau protein in three dimensions. Multicolor ISM was shown on cytoskeletal-associated structural proteins and on 3D four-color images including MitoTracker and Hoechst staining. The simple adaptation of conventional CSD equipment allows superresolution investigations of a broad variety of cell biological questions.
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15
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Monserrate A, Casado S, Flors C. Correlative Atomic Force Microscopy and Localization-Based Super-Resolution Microscopy: Revealing Labelling and Image Reconstruction Artefacts. Chemphyschem 2013; 15:647-50. [DOI: 10.1002/cphc.201300853] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Indexed: 11/10/2022]
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16
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Christenson W, Yermolenko I, Plochberger B, Camacho-Alanis F, Ros A, Ugarova TP, Ros R. Combined single cell AFM manipulation and TIRFM for probing the molecular stability of multilayer fibrinogen matrices. Ultramicroscopy 2013; 136:211-5. [PMID: 24239757 DOI: 10.1016/j.ultramic.2013.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/06/2013] [Accepted: 10/09/2013] [Indexed: 10/26/2022]
Abstract
Adsorption of fibrinogen on various surfaces produces a nanoscale multilayer matrix, which strongly reduces the adhesion of platelets and leukocytes with implications for hemostasis and blood compatibility of biomaterials. The nonadhesive properties of fibrinogen matrices are based on their extensibility, ensuing the inability to transduce strong mechanical forces via cellular integrins and resulting in weak intracellular signaling. In addition, reduced cell adhesion may arise from the weaker associations between fibrinogen molecules in the superficial layers of the matrix. Such reduced stability would allow integrins to pull fibrinogen molecules out of the matrix with comparable or smaller forces than required to break integrin-fibrinogen bonds. To examine this possibility, we developed a method based on the combination of total internal reflection fluorescence microscopy, single cell manipulation with an atomic force microscope and microcontact printing to study the transfer of fibrinogen molecules out of a matrix onto cells. We calculated the average fluorescence intensities per pixel for wild-type HEK 293 (HEK WT) and HEK 293 cells expressing leukocyte integrin Mac-1 (HEK Mac-1) before and after contact with multilayered matrices of fluorescently labeled fibrinogen. For contact times of 500 s, HEK Mac-1 cells show a median increase of 57% of the fluorescence intensity compared to 6% for HEK WT cells. The results suggest that the integrin Mac-1-fibrinogen interactions are stronger than the intermolecular fibrinogen interactions in the superficial layer of the matrix. The low mechanical stability of the multilayer fibrinogen surface may contribute to the reduced cell adhesive properties of fibrinogen-coated substrates. We anticipate that the described method can be applied to various cell types to examine their integrin-mediated adhesion to the extracellular matrices with a variable protein composition.
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Affiliation(s)
- W Christenson
- Department of Physics, Arizona State University, Tempe, AZ 85287, USA; Center for Biological Physics, Arizona State University, Tempe, AZ 85287, USA
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17
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Harder A, Dieding M, Walhorn V, Degenhard S, Brodehl A, Wege C, Milting H, Anselmetti D. Apertureless scanning near-field optical microscopy of sparsely labeled tobacco mosaic viruses and the intermediate filament desmin. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2013; 4:510-6. [PMID: 24062977 PMCID: PMC3778390 DOI: 10.3762/bjnano.4.60] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 08/22/2013] [Indexed: 05/08/2023]
Abstract
Both fluorescence imaging and atomic force microscopy (AFM) are highly versatile and extensively used in applications ranging from nanotechnology to life sciences. In fluorescence microscopy luminescent dyes serve as position markers. Moreover, they can be used as active reporters of their local vicinity. The dipolar coupling of the tip with the incident light and the fluorophore give rise to a local field and fluorescence enhancement. AFM topographic imaging allows for resolutions down to the atomic scale. It can be operated in vacuum, under ambient conditions and in liquids. This makes it ideal for the investigation of a wide range of different samples. Furthermore an illuminated AFM cantilever tip apex exposes strongly confined non-propagating electromagnetic fields that can serve as a coupling agent for single dye molecules. Thus, combining both techniques by means of apertureless scanning near-field optical microscopy (aSNOM) enables concurrent high resolution topography and fluorescence imaging. Commonly, among the various (apertureless) SNOM approaches metallic or metallized probes are used. Here, we report on our custom-built aSNOM setup, which uses commercially available monolithic silicon AFM cantilevers. The field enhancement confined to the tip apex facilitates an optical resolution down to 20 nm. Furthermore, the use of standard mass-produced AFM cantilevers spares elaborate probe production or modification processes. We investigated tobacco mosaic viruses and the intermediate filament protein desmin. Both are mixed complexes of building blocks, which are fluorescently labeled to a low degree. The simultaneous recording of topography and fluorescence data allows for the exact localization of distinct building blocks within the superordinate structures.
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Affiliation(s)
- Alexander Harder
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics and Bielefeld Institute for Biophysics and Nanoscience (BINAS), Bielefeld University, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| | - Mareike Dieding
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics and Bielefeld Institute for Biophysics and Nanoscience (BINAS), Bielefeld University, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| | - Volker Walhorn
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics and Bielefeld Institute for Biophysics and Nanoscience (BINAS), Bielefeld University, Universitätsstrasse 25, D-33615 Bielefeld, Germany
| | - Sven Degenhard
- Department of Molecular Biology and Plant Virology, Institute of Biology, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - Andreas Brodehl
- Erich and Hanna Klessmann Institute for Cardiovascular Research & Development (EHKI), Heart and Diabetes Center NRW, Ruhr University Bochum, Georgstraße 11, D-32545 Bad Oeynhausen, Germany
- Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, University of Calgary, 3280 Hospital Drive NW, T2N4Z6, AB, Canada
| | - Christina Wege
- Department of Molecular Biology and Plant Virology, Institute of Biology, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - Hendrik Milting
- Erich and Hanna Klessmann Institute for Cardiovascular Research & Development (EHKI), Heart and Diabetes Center NRW, Ruhr University Bochum, Georgstraße 11, D-32545 Bad Oeynhausen, Germany
| | - Dario Anselmetti
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics and Bielefeld Institute for Biophysics and Nanoscience (BINAS), Bielefeld University, Universitätsstrasse 25, D-33615 Bielefeld, Germany
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