JoVE Bioengineering
Three-dimensional Optical-resolution Photoacoustic Microscopy
Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis
Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technology capable of imaging optical absorption contrasts in vivo with cellular resolution and sensitivity. Here, we provide a visualized instruction on the experimental protocols of OR-PAM, including system configuration, system alignment, typical in vivo experimental procedures, and functional imaging schemes.
JoVE Bioengineering
Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography
1Department of Biomedical Engineering, Northwestern University, 2Department of Physics, Harbin Institute of Technology, 3Department of Ophthalmology, University of Southern California, 4Department of Ophthalmology, Northwestern University
Photoacoustic ophthalmology (PAOM), an optical-absorption-based imaging modality, provides the complementary evaluation of the retina to the currently available ophthalmic imaging technologies. We report the using of PAOM integrated with spectral-domain optical coherence tomography (SD-OCT) for simultaneous multimodal retinal imaging in rats.
JoVE Neuroscience
A Polished and Reinforced Thinned-skull Window for Long-term Imaging of the Mouse Brain
1Department of Physics, University of California, San Diego, 2Department of Engineering Science and Mechanics, Pennsylvania State University, 3Department of Neurosurgery, Pennsylvania State University, 4Section of Neurobiology, University of California, San Diego
We present a method to form an imaging window in the mouse skull that spans millimeters and is stable for months without inflammation of the brain. This method is well suited for longitudinal studies of blood flow, cellular dynamics, and cell/vascular structure using two-photon microscopy.
JoVE Clinical and Translational Medicine
Transplantation into the Anterior Chamber of the Eye for Longitudinal, Non-invasive In vivo Imaging with Single-cell Resolution in Real-time
1Diabetes Research Institute, University of Miami Miller School of Medicine, 2Department of Surgery, University of Miami Miller School of Medicine, 3Department of Medicine, University of Miami Miller School of Medicine, 4Department of Physiology & Biophysics, University of Miami Miller School of Medicine, 5The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet
A new approach combining intraocular transplantation and confocal microscopy enables longitudinal, non-invasive real-time imaging with single-cell resolution within grafted tissues in vivo. We demonstrate how to transplant pancreatic islets into the anterior chamber of the mouse eye.
JoVE Applied Physics
A Method to Fabricate Disconnected Silver Nanostructures in 3D
1School of Engineering and Applied Sciences, Harvard University, 2Department of Physics, Harvard University
Femtosecond-laser direct-writing is frequently used to create three-dimensional (3D) patterns in polymers and glasses. However, patterning metals in 3D remains a challenge. We describe a method for fabricating silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm.
JoVE Bioengineering
Detection and Isolation of Circulating Melanoma Cells using Photoacoustic Flowmetry
We have developed a flow cytometer using laser induced ultrasound to detect circulating melanoma cells as an early indicator of metastatic disease.
JoVE Neuroscience
Voltage-sensitive Dye Recording from Axons, Dendrites and Dendritic Spines of Individual Neurons in Brain Slices
Department of Cellular and Molecular Physiology, Yale University School of Medicine
An imaging technique for monitoring of membrane potential changes with sub-micrometer spatial and sub-millisecond temporal resolution is described. The technique, based on laser excitation of voltage-sensitive dyes, allows measurements of signals in axons and axon collaterals, terminal dendritic branches, and individual dendritic spines.
JoVE Neuroscience
An Injury Paradigm to Investigate Central Nervous System Repair in Drosophila
Neurodevelopment Group, School of Biosciences, University of Birmingham
An injury paradigm using the Drosophila larval ventral nerve cord to investigate central nervous system regeneration and repair is described. Stabbing followed by laser scanning confocal microscopy in time-lapse and fixed specimens, combined with quantitative analysis with purposefully developed software and genetics, are used to investigate the molecular mechanisms of CNS regeneration and repair.
JoVE Bioengineering
Lensfree On-chip Tomographic Microscopy Employing Multi-angle Illumination and Pixel Super-resolution
1Electrical Engineering Department, University of California, Los Angeles, 2Bioengineering Department, University of California, Los Angeles, 3California NanoSystems Institute, University of California, Los Angeles
Lensfree optical tomography is a three-dimensional microscopy technique that offers a spatial resolution of <1 μm × <1 μm × <3 μm in x, y and z dimensions, respectively, over a large imaging-volume of 15-100 mm3, which can be particularly useful for integration with lab-on-a-chip platforms.
JoVE General
Assembly, Tuning and Use of an Apertureless Near Field Infrared Microscope for Protein Imaging
1Department of Chemistry, University of Toronto, 2Department of Chemistry, University of Wisconsin, 3Department of Chemistry, Duke University
The assembly of a nearfield infrared microscope for imaging protein aggregates is described.
JoVE General
Nano-fEM: Protein Localization Using Photo-activated Localization Microscopy and Electron Microscopy
Department of Biology, Howard Hughes Medical Institute, University of Utah
We describe a method to localize fluorescently tagged proteins in electron micrographs. Fluorescence is first localized using photo-activated localization microscopy on ultrathin sections. These images are then aligned to electron micrographs of the same section.
JoVE Bioengineering
Wide-field Fluorescent Microscopy and Fluorescent Imaging Flow Cytometry on a Cell-phone
1Electrical Engineering Department, University of California, Los Angeles, 2Bioengineering Department, University of California, Los Angeles, 3California NanoSystems Institute (CNSI), University of California, Los Angeles
We review our recent results on the integration of fluorescent microscopy and imaging flow cytometry tools on a cell-phone using compact and cost-effective opto-fluidic attachments. These cell-phone based micro-analysis devices might be useful for cytometric analysis, such as performing various cell counting tasks as well as for high-throughput screening of e.g., water samples in resource limited settings.
JoVE Neuroscience
Thinned-skull Cortical Window Technique for In Vivo Optical Coherence Tomography Imaging
1Division of Biomedical Sciences, University of California, Riverside, 2Department of Bioengineering, University of California, Riverside
We present a method of creating a thinned-skull cortical window (TSCW) in a mouse model for in vivo OCT imaging of the cerebral cortex.
JoVE Neuroscience
Intact Histological Characterization of Brain-implanted Microdevices and Surrounding Tissue
1Weldon School of Biomedical Engineering, Purdue University, 2Department of Biological Sciences, Purdue University
Here we present a histological method for capturing, labeling, optically clearing, and imaging the intact brain tissue interface around chronically implanted microdevices in rodent brain tissue. Results from the techniques comprising this method are useful for understanding the impact of various penetrating brain-implants on their surrounding tissue.
JoVE Bioengineering
In vitro Synthesis of Native, Fibrous Long Spacing and Segmental Long Spacing Collagen
1Department of Chemistry, University of Toronto, 2Institute for Optical Sciences, University of Toronto
Simple and reproducible procedures are described for making three structurally distinct collagen assemblies from a common commercially available Type I collagen monomer. Native type, fibrous long spacing or segmental long spacing collagen can be constructed by varying the conditions to which the 300 nm long and 1.4 nm diameter monomer building block is exposed.
JoVE Bioengineering
Nanotopology of Cell Adhesion upon Variable-Angle Total Internal Reflection Fluorescence Microscopy (VA-TIRFM)
Hochschule Aalen, Institut für Angewandte Forschung
Topology of cell adhesion on a substrate is measured with nanometre precision by variable-angle total internal reflection fluorescence microscopy (VA-TIRFM).
JoVE Applied Physics
Characterization of Surface Modifications by White Light Interferometry: Applications in Ion Sputtering, Laser Ablation, and Tribology Experiments
1Materials Science Division, Argonne National Laboratory, 2Energy Systems Division, Argonne National Laboratory, 3MassThink LLC
White light microscope interferometry is an optical, noncontact and quick method for measuring the topography of surfaces. It is shown how the method can be applied toward mechanical wear analysis, where wear scars on tribological test samples are analyzed; and in materials science to determine ion beam sputtering or laser ablation volumes and depths.
JoVE General
Quantitative Analysis of Autophagy using Advanced 3D Fluorescence Microscopy
1Department of Biochemistry and Molecular Medicine, University of California, Davis, 2NSF Center for Biophotonics Science & Technology, University of California, Davis, 3University of Tromsø, 4Department of Surgery (Division of Surgical Oncology), University of California, Davis, 5UC Davis Comprehensive Cancer Center, University of California, Davis, 6Department of Biological Chemistry, University of California, Davis
Autophagy is a ubiquitous process that enables cells to degrade and recycle proteins and organelles. We apply advanced fluorescence microscopy to visualize and quantify the small, but essential, physical changes associated with the induction of autophagy, including the formation and distribution of autophagosomes and lysosomes, and their fusion into autolysosomes.
JoVE General
Phase Contrast and Differential Interference Contrast (DIC) Microscopy
Core Optical Imaging Facility, University of Texas Health Science Center at San Antonio (UTHSCSA)
This protocol highlights the principles and practical applications of Phase and Differential Interference Contrast (DIC) Microscopy
JoVE Neuroscience
Cerebral Blood Oxygenation Measurement Based on Oxygen-dependent Quenching of Phosphorescence
1Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 2Department of Biochemistry and Biophysics, University of Pennsylvania, 3Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, 4Departments of Neurosciences and Radiology, University of California
We present an experimental procedure for measuring the partial pressure of oxygen (pO2) in cerebral vasculature based on oxygen-dependent quenching of phosphorescence. Animal preparation and imaging procedures were outlined for both large field of view CCD-based imaging of pO2 in rats and 2-photon excitation based imaging of pO2 in mice.
JoVE Bioengineering
Video-rate Scanning Confocal Microscopy and Microendoscopy
1Program in Biophysics, Harvard University, 2Division of Health Sciences and Technology, Harvard-MIT, 3Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School
The complete construction of a custom, real-time confocal scanning imaging system is described. This system, which can be readily used for video-rate microscopy and microendoscopy, allows for an array of imaging geometries and applications not accessible using standard commercial confocal systems, at a fraction of the cost.
JoVE Neuroscience
Multiphoton Microscopy of Cleared Mouse Brain Expressing YFP
1Department of Biomedical Engineering, Yale University, 2Department of Biomedical Engineering, Louisiana Tech University
Multiphoton microscopy of whole mouse organs is possible by optically clearing the organ before imaging, but not all protocols preserve the fluorescent signal of fluorescent proteins. Using an optical clearing method with ethanol-based dehydration and benzyl alcohol:benzyl benzoate clearing, we show high-resolution multiphoton images of whole mouse brain expressing YFP.
JoVE Bioengineering
Lensless Fluorescent Microscopy on a Chip
Department of Electrical Engineering, University of California, Los Angeles
A lensless on-chip fluorescent microscopy platform is demonstrated that can image fluorescent objects over an ultra-wide field-of-view of e.g., >0.6-8 cm2 with <4μm resolution using a compressive sampling based decoding algorithm. Such a compact and wide-field fluorescent on-chip imaging modality could be valuable for high-throughput cytometry, rare-cell research and microarray-analysis.
JoVE Neuroscience
In Vivo Two-photon Imaging Of Experience-dependent Molecular Changes In Cortical Neurons
1Unit on Neural Circuits and Adaptive Behaviors, Genes Cognition and Psychosis Program, National Institute of Mental Health, 2Department of Neuroscience, Brown University - National Institutes of Health Graduate Partnership Program, 3Section on Synaptic Pharmacology, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, 4Champalimaud Neuroscience Programme, Champalimaud Center for the Unknown
Experience-dependent molecular changes in neurons are essential for the brain's ability to adapt in response to behavioral challenges. An in vivo two-photon imaging method is described here that allows the tracking of such molecular changes in individual cortical neurons through genetically encoded reporters.
JoVE Neuroscience
High-resolution Live Imaging of Cell Behavior in the Developing Neuroepithelium
1Neural Development Group, Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee, UK, 2Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, UK
Imaging embryonic tissue in real-time is challenging over long periods of time. Here we present an assay for monitoring cellular and sub-cellular changes in chick spinal cord for long periods with high spatial and temporal resolution. This technique can be adapted for other regions of the nervous system and developing embryo.
JoVE Applied Physics
Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells
1Center for Innovative Fuel Cells and Battery Technologies, School of Materials Science and Engineering, Georgia Institute of Technology, 2School of Chemistry and Biochemistry, Georgia Institute of Technology
We present a unique platform for characterizing electrode surfaces in solid oxide fuel cells (SOFCs) that allows simultaneous performance of multiple characterization techniques (e.g. in situ Raman spectroscopy and scanning probe microscopy alongside electrochemical measurements). Complementary information from these analyses may help to advance toward a more profound understanding of electrode reaction and degradation mechanisms, providing insights into rational design of better materials for SOFCs.
JoVE General
Mesoscopic Fluorescence Tomography for In-vivo Imaging of Developing Drosophila
1Center for Systems Biology, Massachusetts General Hospital, 2Institute for Biological and Medical Imaging (IBMI), Technical University of Munich and Helmholtz Center Munich, 3Department of Genetics, Harvard Medical School and Howard Hughes Medical Institute
Mesoscopic fluorescence tomography operates beyond the penetration limits of tissue-sectioning fluorescence microscopy. The technique is based on multi-projection illumination and a photon transport description. We demonstrate in-vivo whole-body 3D visualization of the morphogenesis of GFP-expressing wing imaginal discs in Drosophila melanogaster.
JoVE General
Optical Recording of Electrical Activity in Guinea-pig Enteric Networks using Voltage-sensitive Dyes
1Department of Neuroscience, University of Pennsylvania-School of Medicine, 2Department of Physiology, University of Pennsylvania-School of Medicine
This protocol illustrates how voltage-sensitive dyes enable optical recording of electrical activity from intact neural networks such as the plexuses of the guinea-pig enteric nervous system, with an adjustable resolution that ranges from single-cells to multi-ganglionic circuitry.
JoVE Applied Physics
Micro 3D Printing Using a Digital Projector and its Application in the Study of Soft Materials Mechanics
Department of Mechanical Engineering, Massachusetts Institute of Technology
We demonstrate controlled pattern transformation of swelling gel tubes by elastic instability. A simple projection micro stereo-lithography setup is built using an off-the-shelf digital data projector to fabricate three-dimensional polymeric structures in a layer-by-layer fashion. Swelling hydrogel tubes under mechanical constraint display various circumferential buckling modes depending on dimension.
JoVE Editorial
August 2012: This Month in JoVE
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
Traditional microscopy requires lens objectives to magnify specimens, and can involve numerous optical components like additional objectives, filters, and mirrors to refract and direct light to optical sensors. The August 2012 issue of JoVE (Journal of Visualized Experiments) is marked by the third publication from the Ozcan Lab (University of California, Los Angeles) on their lens-free "on-chip" microscopy platform, which they have pioneered.
JoVE Neuroscience
Imaging pHluorin-tagged Receptor Insertion to the Plasma Membrane in Primary Cultured Mouse Neurons
By tagging the extracellular domains of membrane receptors with superecliptic pHluorin, and by imaging these fusion receptors in cultured mouse neurons, we can directly visualize individual vesicular insertion events of the receptors to the plasma membrane. This technique will be instrumental in elucidating the molecular mechanisms governing receptor insertion to the plasma membrane.
JoVE Bioengineering
High-resolution Fiber-optic Microendoscopy for in situ Cellular Imaging
1Department of Bioengineering, Rice University, 2Department of Molecular and Cellular Oncology, The Univeristy of Texas M. D. Anderson Cancer Center
In many biological and clinical situations it is advantageous to study cellular processes as they evolve in their native microenvironment. Here we describe the assembly and use of a low-cost fiber-optic microscope which can provide real time imaging in cell culture, animal studies, and clinical patient studies.
JoVE Neuroscience
Calcium Imaging of Odor-evoked Responses in the Drosophila Antennal Lobe
1Center for Integrative Genomics, University of Lausanne, 2Department of Biology, University of Konstanz
We describe an established technique to measure and analyze odor-evoked calcium responses in the antennal lobe of living Drosophila melanogaster.
JoVE Bioengineering
Graphene Coatings for Biomedical Implants
1Department of Physics, Clemson University, 2Department of Pharmacology and Toxicology, East Carolina University, 3Department of Bioengineering, Clemson University, 4Center for Optical Materials Science and Engineering Technologies, Clemson University
Graphene offers potential as a coating material for biomedical implants. In this study we demonstrate a method for coating nitinol alloys with nanometer thick layers of graphene and determine how graphene may influence implant response.
JoVE General
Two-Photon-Based Photoactivation in Live Zebrafish Embryos
Molecular Cell Biology, Weizmann Institute of Science
Multiphoton microscopy allows control of low energy photons with deep optical penetration and reduced phototoxicity. We describe the use of this technology for live cell labeling in zebrafish embryos. This protocol can be readily adapted for photo-induction of various light-responsive molecules.
JoVE Neuroscience
Sequential Photo-bleaching to Delineate Single Schwann Cells at the Neuromuscular Junction
1Lehrstuhl für Biomolekulare Sensoren, Technische Universität München, 2Center for Integrated Protein Science (Munich) at the Institute of Neuroscience, Technische Universität München, 3TUM Institute for Advanced Study and German Center for Neurodegenerative Diseases, Technische Universität München, 4Munich Cluster for Systems Neurology (SyNergy), Technische Universität München
Visualizing individual cells in densely packed tissues, such as terminal Schwann cells (SCs) at neuromuscular junctions (NMJs), is challenging. "Sequential photo-bleaching" allows delineating single terminal SCs, for instance in the triangularis sterni muscle explant, a convenient nerve-muscle preparation, where sequential bleaching can be combined with time-lapse imaging and post-hoc immunostainings.
JoVE Immunology and Infection
A TIRF Microscopy Technique for Real-time, Simultaneous Imaging of the TCR and its Associated Signaling Proteins
The compartmentalization of proteins either within the plasma membrane or into intracellular locations is one regulatory mechanism that can greatly influence signaling outcomes; hence, to understand signaling it is important to study the spatial and temporal behavior of the proteins involved. We describe here a TIRF microscopy based system to study signal transduction in T cells, but is broadly applicable.
JoVE Neuroscience
Targeted Labeling of Neurons in a Specific Functional Micro-domain of the Neocortex by Combining Intrinsic Signal and Two-photon Imaging
Department of Neuroscience, Medical University of South Carolina
A method is described for labeling neurons with fluorescent dyes in predetermined functional micro-domains of the neocortex. First, intrinsic signal optical imaging is used to obtain a functional map. Then two-photon microscopy is used to label and image neurons within a micro-domain of the map.
JoVE Clinical and Translational Medicine
Molecular Imaging to Target Transplanted Muscle Progenitor Cells
1Imaging Program, Lawson Health Research Institute, 2Department of Anatomy and Cell Biology, Western University, 3Department of Medical Biophysics, Western University
A non-invasive means to evaluate the success of myoblast transplantation is described. The method takes advantage of a unified fusion reporter gene composed of genes whose expression can be imaged with different imaging modalities. Here, we make use of a fluc reporter gene sequence to target cells via bioluminescence imaging.
JoVE Bioengineering
Patterned Photostimulation with Digital Micromirror Devices to Investigate Dendritic Integration Across Branch Points
Department of Neurology, Baltimore VA Medical Center, University of Maryland School of Medicine
Digital micromirror devices (DMD) can generate complex patterns in time and space with which to control neuronal excitability. Issues relevant to the design, construction, and operation of DMD systems are discussed. Such a system enabled the demonstration of non-linear integration across distal dendritic branch points.
JoVE Neuroscience
A Rapid Approach to High-Resolution Fluorescence Imaging in Semi-Thick Brain Slices
1Department of Molecular & Human Genetics, Baylor College of Medicine (BCM), 2Precisionary Instruments Inc., 3Departments of Molecular & Human Genetics and Neuroscience, Baylor College of Medicine (BCM), 4Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital
Here we describe a rapid and simple method to image fluorescently labeled cells in semi-thick brain slices. By fixing, slicing, and optically clearing brain tissue we describe how standard epifluorescent or confocal imaging can be used to visualize individual cells and neuronal networks within intact nervous tissue.
JoVE Immunology and Infection
Use of an Optical Trap for Study of Host-Pathogen Interactions for Dynamic Live Cell Imaging
1Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, 2Department of Mechanical and Aerospace Engineering, The Ohio State University, 3Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, 4Dept. of Chemical and Biomolecular Engineering, Vanderbilt University
A method is described to individually select, manipulate, and image live pathogens using an optical trap coupled to a spinning disk microscope. The optical trap provides spatial and temporal control of organisms and places them adjacent to host cells. Fluorescence microscopy captures dynamic intercellular interactions with minimal perturbation to cells.
JoVE General
Live Cell Response to Mechanical Stimulation Studied by Integrated Optical and Atomic Force Microscopy
1Department of Systems Biology and Translational Medicine, College of Medicine, Cardiovascular Research Institute, Texas A&M Health Science Center, 2Department of Biomedical Engineering, Texas A&M University
This paper aims to instruct the reader in the operation of an integrated atomic force-optical imaging microscope for mechanical stimulation of live cells in culture. A step-by-step protocol is presented. A representative data set that shows live cell response to mechanical stimulation is presented.
JoVE Applied Physics
Bringing the Visible Universe into Focus with Robo-AO
1Caltech Optical Observatories, California Institute of Technology, 2Department of Astronomy, California Institute of Technology, 3Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 4Inter-University Centre for Astronomy & Astrophysics, 5Observatories of the Carnegie Institution for Science, 6Benoziyo Center for Astrophysics, Weizmann Institute of Science
Light from astronomical objects must travel through the earth's turbulent atmosphere before it can be imaged by ground-based telescopes. To enable direct imaging at maximum theoretical angular resolution, advanced techniques such as those employed by the Robo-AO adaptive-optics system must be used.
JoVE Clinical and Translational Medicine
Near Infrared Optical Projection Tomography for Assessments of β-cell Mass Distribution in Diabetes Research
1Umeå Centre for Molecular Medicine, Umeå University, 2Cell Transplant Center, Diabetes Research Institute, University of Miami,, 3EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Catalan Institute of Research and Advanced Studies, 4Dept. of Computing Science, Umeå University
We describe the adaptation of optical projection tomography (OPT)1 to imaging in the near infrared spectrum, and the implementation of a number of computational tools. These protocols enable assessments of pancreatic β-cell mass (BCM) in larger specimens, increase the multichannel capacity of the technique and increase the quality of OPT data.
JoVE Bioengineering
Optical Frequency Domain Imaging of Ex vivo Pulmonary Resection Specimens: Obtaining One to One Image to Histopathology Correlation
1Department of Pathology, Harvard Medical School, 2Massachusetts General Hospital, 3Wellman Center for Photomedicine, Harvard Medical School, 4Pulmonary and Critical Care Unit, Massachusetts General Hospital, 5Pulmonary and Critical Care Unit, Harvard Medical School
A method to image ex vivo pulmonary resection specimens with optical frequency domain imaging (OFDI) and obtain precise correlation to histology is described, which is essential to developing specific OFDI interpretation criteria for pulmonary pathology. This method is applicable to other tissue types and imaging techniques to obtain precise imaging to histology correlation for accurate image interpretation and assessment. Imaging criteria established with this technique would then be applicable to image assessment in future in vivo studies.
JoVE General
Using High Resolution Computed Tomography to Visualize the Three Dimensional Structure and Function of Plant Vasculature
1U.S. Department of Agriculture, 2Department of Viticulture and Enology, University of California - Davis, 3Hawkesbury Institute for the Environment, University of Western Sydney, 4Advanced Light Source, Lawrence Berkeley National Lab, 5Citrus Research & Education Center, University of Florida
High resolution x-ray computed tomography (HRCT) is a non-destructive diagnostic imaging technique that can be used to study the structure and function of plant vasculature in 3D. We demonstrate how HRCT facilitates exploration of xylem networks across a wide range of plant tissues and species.
JoVE Bioengineering
Visualizing Proteins and Macromolecular Complexes by Negative Stain EM: from Grid Preparation to Image Acquisition
1Graduate Group in Biophysics, University of California San Francisco, 2Department of Biochemistry and Biophysics, University of California San Francisco
Visualizing protein samples by negative stain electron microscopy (EM) has become a popular structural analysis method. It is useful for quantitative structural analysis, such as calculating a 3D reconstruction of the molecules being studied, and also for qualitative examination of the quality of protein preparations. In this article we present detailed protocols for preparing the EM grids, staining the sample and visualizing the sample in an electron microscope. Novice users can follow these protocols easily and to utilize negative stain EM as a routine assay, in addition to other biochemical assays, for evaluating their protein samples.
JoVE Applied Physics
Development of Whispering Gallery Mode Polymeric Micro-optical Electric Field Sensors
Mechanical Engineering Department, Southern Methodist University
A high-sensitivity photonic micro sensor was developed for electric field detection. The sensor exploits the optical modes of a dielectric sphere. Changes in the external electric field perturb the sphere morphology leading to shifts in its optical modes. The electric field strength is measured by monitoring these optical shifts.
JoVE Immunology and Infection
Structure of HIV-1 Capsid Assemblies by Cryo-electron Microscopy and Iterative Helical Real-space Reconstruction
Department of Structural Biology, University of Pittsburgh School of Medicine
This article describes a method to obtain a three-dimensional (3D) structure of helically assembled molecules using cryo-electron microscopy. In this protocol, we use HIV-1 capsid assemblies to illustrate the detailed 3D reconstruction procedure for achieving a density map by the iterative helical real-space reconstruction method.
More Results...
