JoVE General
MALDI Sample Preparation: the Ultra Thin Layer Method
Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University
This video demonstrates the preparation of an ultra-thin matrix/analyte layer for analyzing peptides and proteins by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS).
JoVE Applied Physics
Revealing Dynamic Processes of Materials in Liquids Using Liquid Cell Transmission Electron Microscopy
Materials Sciences Division, Lawrence Berkeley National Laboratory
We have developed a self-contained liquid cell, which allows imaging through liquids using a transmission electron microscope. Dynamic processes of nanoparticles in liquids can be revealed in real time with sub-nanometer resolution.
JoVE Applied Physics
Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping
School of Photovoltaics, University of New South Wales
Polycrystalline silicon thin-film solar cells on glass are fabricated by deposition of boron and phosphorous doped silicon layers followed by crystallisation, defect passivation and metallisation. Plasmonic light-trapping is introduced by forming Ag nanoparticles on the silicon cell surface capped with a diffused reflector resulting in ~45% photocurrent enhancement.
JoVE Bioengineering
Solid-phase Submonomer Synthesis of Peptoid Polymers and their Self-Assembly into Highly-Ordered Nanosheets
Molecular Foundry, Lawrence Berkeley National Laboratory
A simple and general manual peptoid synthesis method involving basic equipment and commercially available reagents is outlined, enabling peptoids to be easily synthesized in most laboratories. The synthesis, purification and characterization of an amphiphilic peptoid 36mer is described, as well as its self-assembly into highly-ordered nanosheets.
JoVE Bioengineering
Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma
Department of Mechanical and Aerospace Engineering, The George Washington University
Anodic arc discharge is one of the most practical and efficient methods to synthesize various carbon nanostructures. To increase the arc controllability and flexibility, a non-uniform magnetic field was introduced to process the one-step synthesis of large-scale graphene flakes and high-purity single-walled carbon nanotubes.
JoVE Chemistry
Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development
ISOF - Bio Free Radicals, Consiglio Nazionale delle Ricerche
Radical-based biomimetic chemistry has been applied to building-up libraries necessary for biomarker development.
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 Clinical and Translational Medicine
Corneal Donor Tissue Preparation for Endothelial Keratoplasty
1Department of Ophthalmology, University of Michigan, 2MidWest Eye Banks
Endothelial corneal transplantation is a surgical technique for treatment of posterior corneal diseases. Mechanical microkeratome dissection to prepare tissue results in thinner, more symmetric grafts with less endothelial cell loss and improved outcomes. Dissections can be performed at the eye bank prior to corneal transplantation surgery.
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
Inducing Dendritic Growth in Cultured Sympathetic Neurons
Department of Molecular Biosciences, University of California, Davis
We describe a protocol for using bone morphogenetic protein-7 (BMP-7) or Matrigel to selectively induce dendritic growth in primary sympathetic neurons dissociated from the superior cervical ganglia (SCG) of perinatal rats.
JoVE Neuroscience
Multi-electrode Array Recordings of Neuronal Avalanches in Organotypic Cultures
Section on Critical Brain Dynamics, National Institute of Mental Health
A robust way to study neuronal avalanches, i.e. scale-invariant spatio-temporal activity bursts, indicative of critical state dynamics in cortex. Avalanches emerge spontaneously in developing superficial layers of cultured cortex which allows for long-term measurements of the activity with planar integrated multi-electrode arrays (MEA) under precisely controlled conditions.
JoVE Neuroscience
Strategies for Study of Neuroprotection from Cold-preconditioning
Department of Neurology, The University of Chicago Medical Center
We seek to define the neural immune signaling responsible for cold-preconditioning as means to identify novel targets for therapeutics development to protect brain before injury onset. We present strategies for such work that require biological systems, experimental manipulations plus technical capacities that are highly reproducible and sensitive.
JoVE Clinical and Translational Medicine
Biomarkers in an Animal Model for Revealing Neural, Hematologic, and Behavioral Correlates of PTSD
1Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Services University of the Health Sciences, Bethesda, Maryland, 2Department of Gene and Protein Biomarkers, GenProMarkers, Inc.
We describe a rat model of post traumatic stress disorder (PTSD) that reveals the persistent alterations in neuroendocrine function and the delayed long-term, exaggerated fear response, characteristic of PTSD patients. The animal model and methods described here are useful for correlating biomarkers in brain nuclei, which are mechanistic but cannot be measured in patients, with biomarkers in peripheral white blood cells, which can.
JoVE Application Notes
Orflo Moxi - ADVERTISEMENT
Moxi Z is the only automated cell counter that combines the Coulter Principle typically used in high-end cell counters with a patented thin-film sensor technology to allow for highly accurate (> 95%) and repeatable particle counting and sizing for a broad range of cell types - from mammalian cells to cells as small as wine yeast and more. Since today's workflows demand accurate quality control of samples, determining cell counts precisely has a significant impact on outcomes and downstream costs.
JoVE Clinical and Translational Medicine
A Human Fallopian Tube Model for Investigation of C. trachomatis Infections
1Institute of Medical Microbiology and Hygiene, University of Lübeck, 2Institute of Anatomie, University of Lübeck, 3Department of Obstetrics and Gynecology, University Hospital of Schleswig-Holstein, University of Lübeck, 4Medical Clinic III, University Hospital of Schleswig-Holstein, University of Lübeck
We describe an ex vivo infection model for visualisation of direct interactions from bacterial pathogens with human fallopian tube cells. The whole organ tissue model was established to investigate C. trachomatis induced pathology to the female fallopian tube under "life-like" conditions.
JoVE Chemistry
Fabricating Nanogaps by Nanoskiving
The fabrication of electrically addressable, high-aspect-ratio (> 1000:1) metal nanowires separated by gaps of single nanometers using either sacrificial layers of aluminum and silver or self-assembled monolayers as templates is described. These nanogap structures are fabricated without a clean room or any photo- or electron-beam lithographic processes by a form of edge lithography known as nanoskiving.
JoVE General
Microfluidic Chips Controlled with Elastomeric Microvalve Arrays
Dept. of Bioengineering, University of Washington
We demonstrate protocols for manufacturing and automating elastomeric polydimethylsiloxane (PDMS)-based microvalve arrays that need no extra energy to close and feature photolithographically defined precise volumes. A parallel subnanoliter-volume mixer and an integrated microfluidic perfusion system are presented.
JoVE Applied Physics
Atom Probe Tomography Studies on the Cu(In,Ga)Se2 Grain Boundaries
1Department of Microstructure Physics and Alloy Design, Max-Planck-Institut für Eisenforschung GmbH, 2Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg ( ZSW )
In this work, we describe the use of the atom-probe tomography technique for studying the grain boundaries of the absorber layer in a CIGS solar cell. A novel approach to prepare the atom probe tips containing the desired grain boundary with a known structure is also presented here.
JoVE Editorial
October 2012: This Month in JoVE
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
Here are some highlights from the October 2012 Issue of Journal of Visualized Experiments (JoVE).
JoVE Applied Physics
Fabrication of Silica Ultra High Quality Factor Microresonators
1Department of Chemical Engineering and Materials Science, University of Southern California, 2Department of Electrical Engineering-Electrophysics, University of Southern California
We describe the use of a carbon dioxide laser reflow technique to fabricate silica resonant cavities, including free-standing microspheres and on-chip microtoroids. The reflow method removes surface imperfections, allowing long photon lifetimes within both devices. The resulting devices have ultra high quality factors, enabling applications ranging from telecommunications to biodetection.
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 General
Purification of the M. magneticum Strain AMB-1 Magnetosome Associated Protein MamAΔ41
MamA is a unique Magnetosome associated protein which was shown to be involved in magnetosome activation. Here we present the purification protocol of MamA deletion mutant (MamAΔ41) from M. magneticum AMB-1.
JoVE Clinical and Translational Medicine
Imaging Glioma Initiation In Vivo Through a Polished and Reinforced Thin-skull Cranial Window
By combining a polished and reinforced thin-skull (PoRTS) cranial window and glioblastoma (GBM) cell injection, we can observe glioma initiation and growth from injected GBM cells in the brain of a live mouse longitudinally.
JoVE General
Cell Block Preparation from Cytology Specimen with Predominance of Individually Scattered Cells
Department of Pathology, University of Wisconsin - Milwaukee
Shidham's method for preparation of cell blocks with AV-marker from cytology specimens containing individually scattered cells and small cell groups.
JoVE Applied Physics
Nanomoulding of Functional Materials, a Versatile Complementary Pattern Replication Method to Nanoimprinting
1Institute of Microengineering (IMT), Photovoltaics and Thin Film Electronics Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), 2Department of Electrical Engineering and Computer Sciences, University of California, Berkeley
We describe a nanomoulding technique which allows low-cost nanoscale patterning of functional materials, materials stacks and full devices. Nanomoulding can be performed on any nanoimprinting setup and can be applied to a wide range of materials and deposition processes.
JoVE Bioengineering
A Microfluidic Device for Studying Multiple Distinct Strains
We present a simple method to produce microfluidic devices capable of applying similar dynamic conditions to multiple distinct strains, without the need for a clean room or soft lithography.
JoVE Neuroscience
Mitochondria-associated ER Membranes (MAMs) and Glycosphingolipid Enriched Microdomains (GEMs): Isolation from Mouse Brain
Department of Genetics, St Jude Children's Research Hospital
This procedure illustrates how to isolate from the adult mouse brain the mitochondria-associated ER membranes or MAMs and the glycosphingolipid-enriched microdomain fractions from MAMs and mitochondrial preparations.
JoVE Neuroscience
High-density EEG Recordings of the Freely Moving Mice using Polyimide-based Microelectrode
1Center for Neural Science , Korea Institute of Science and Technology (KIST), 2Department of Neuroscience, University of Science and Technology, 3Fab Service Department, Korea Advanced Nano Fab Center
In this article, we described the surgery procedure and handling tips for implantation of ultra-thin polyimide-based microelectrode array (PBM-array) on the mouse skull for acquisition of high-density encephalography (EEG) in a mouse model.
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 Applied Physics
Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures
1Institute for Solid State Research, IFW-Dresden, 2Institute of Metal Physics of National Academy of Sciences of Ukraine, 3Diamond Light Source LTD, 4Department of Physics, University of Johannesburg, 5CNR-SPIN, and Dipartimento di Fisica "E. R. Caianiello", Università di Salerno, 6Institute of Physics of Complex Matter, École Polytechnique Fédérale de Lausanne
The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.
JoVE General
DNA Extraction from 0.22 μM Sterivex Filters and Cesium Chloride Density Gradient Centrifugation
Department of Microbiology and Immunology, University of British Columbia - UBC
We describe a method for extraction of high molecular weight genomic DNA from planktonic biomass concentrated on 0.22 μm Sterivex filters, followed by cesium chloride density gradient centrifugation for purification.
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 General
Electron Cryotomography of Bacterial Cells
1Division of Biology, California Institute of Technology - Caltech, 2Howard Hughes Medical Institute, California Institute of Technology - Caltech
We illustrate here how to use electron cryotomography (ECT) to study the ultrastructure of bacterial cells in near-native states, to "macromolecular" (~4 nm) resolution.
JoVE General
Upright Imaging of Drosophila Embryos
1Department of Biology, Case Western Reserve University, 2Department of Genetics, Case Western Reserve University
Here we present a mounting protocol for stained Drosophila embryos in an upright position that allows imaging of cross-sections using Confocal microscopy.
JoVE Neuroscience
Isolation and Culture of Neural Crest Stem Cells from Human Hair Follicles
Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania
This article presents a robust protocol for isolation and culture of neural crest stem cells from human hair follicles.
JoVE General
A Step-by-step Method for the Reconstitution of an ABC Transporter into Nanodisc Lipid Particles
Department of Biochemistry and Molecular Biology, University of British Columbia
Nanodiscs are small discoid particles that incorporate membrane proteins into a small patch of phospholipid bilayer. We provide a visual protocol that shows the step-by-step incorporation of the MalFGK2 transporter into a disc.
JoVE General
The Gateway to the Brain: Dissecting the Primate Eye
1Department of Physiology, University of Montreal, 2School of Optometry, University of Montreal, 3Departement de chimie-biologie, Universite du Quebec a Trois-Rivieres
The non-human primate is an important translational species for our understanding of development and aging. The anatomical organization of the primate retina may provide important insights into normal and pathological conditions in humans.
JoVE Bioengineering
Studying Cell Rolling Trajectories on Asymmetric Receptor Patterns
1Department of Materials Science and Engineering, MIT - Massachusetts Institute of Technology, 2Department of Mechanical Engineering, MIT - Massachusetts Institute of Technology, 3HST Center for Biomedical Engineering and Harvard Stem Cell Institute, Brigham and Women's Hospital and Harvard Medical School
We describe a protocol to observe and analyze cell rolling trajectories on asymmetric receptor-patterned substrates. The resulting data are useful for engineering of receptor-patterned substrates for label-free cell separation and analysis.
JoVE General
Microfabrication of Chip-sized Scaffolds for Three-dimensional Cell cultivation
1Institute for Biological Interfaces, Karlsruhe Research Centre, 2Institute for BioMedical Technology, University of Twente, 3Department of Materials Research, Institute for Heavy Ion Research, 4Institute of Microstructure Technology, Karlsruhe Research Centre, 5Institute for Micro Process Engineering, Karlsruhe Research Centre
We present two processes for the microfabrication of porous polymer chips for three-dimensional cell cultivation. The first one is hot embossing combined with a solvent vapour welding process. The second one uses a recently developed microthermoforming process combined with ion track technology leading to a significant simplification of manufacture.
JoVE General
Arabidopsis thaliana Polar Glycerolipid Profiling by Thin Layer Chromatography (TLC) Coupled with Gas-Liquid Chromatography (GLC)
Department of Biochemistry and Molecular Biology, Michigan State University
Composition of polar lipid extracts and the fatty acid composition of individual glycerolipids are determined in a simple and robust lipid profiling experiment. For this purpose, glycerolipids are isolated by thin layer chromatography and subjected to transmethylation of their acyl groups. Fatty acyl methylesters are quantified by gas-liquid chromatography.
JoVE Neuroscience
Progressive-ratio Responding for Palatable High-fat and High-sugar Food in Mice
CRCHUM and the Montreal Diabetes Research Center, University of Montreal
The present report details the protocol employed to measure the rewarding effects of high-fat food in mice using a progressive ratio operant conditioning task.
JoVE General
Preparation of Dissociated Mouse Cortical Neuron Cultures
Department of Anatomy and Neurobiology, University of California, Irvine (UCI)
This video shows a procedure for generating neuronal cultures from late embryo and early postnatal mouse cortex. These cultures can be used for immunocytochemistry, biochemistry, electrophysiology, calcium and sodium imaging and provide a platform to study the neuronal development of transgenic animals that carry a postnatal lethal gene mutation.
JoVE Applied Physics
Synthesis and Operation of Fluorescent-core Microcavities for Refractometric Sensing
Department of Physics, University of Alberta
Fluorescent-core microcavity sensors employ a high-index quantum-dot coating in the channel of silica microcapillaries. Changes in the refractive index of fluids pumped into the capillary channel cause shifts in the microcavity fluorescence spectrum that can be used to analyze the channel medium.
JoVE Bioengineering
Quantifying the Mechanical Properties of the Endothelial Glycocalyx with Atomic Force Microscopy
Department of Biomedical Engineering, University of Rochester
The mechanical characteristics of endothelial glycocalyx were measured by indentation using micron sized spheres on AFM cantilevers. Endothelial cells were cultured in a custom chamber under physiological flow conditions to induce glycocalyx expression. Data were analyzed using a thin film model to determine the glycocalyx thickness and modulus.
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
Micropunching Lithography for Generating Micro- and Submicron-patterns on Polymer Substrates
Mechanical and Aerospace Engineering, University of Texas at Arlington
A micropunching lithography approach is developed to generate micro- and submicron-patterns on top, sidewall and bottom surfaces of polymer substrates. It overcomes the obstacles of patterning conducting polymers and generating sidewall patterns. This method allows rapid fabrication of multiple features and is free of aggressive chemistry.
JoVE Neuroscience
Live Imaging of Dorsal Root Axons after Rhizotomy
1Temple University, Shriners Hospitals Pediatric Research Center and Department of Anatomy and Cell Biology, 2Medical Research Service, Department of Veterans Affairs Hospital, 3Department of Neurobiology and Anatomy, Drexel University College of Medicine, 4Shriners Hospitals Pediatric Research Center and Department of Anatomy and Cell Biology, Temple University School of Medicine
An in vivo imaging protocol to monitor primary sensory axons following dorsal root crush is described. The procedures utilize wide-field fluorescence microscopy and thy1-YFP transgenic mice, and permit repeated imaging of axon regeneration over 4 cm in the PNS and axon interactions with the interface of the CNS.
JoVE Chemistry
Origami Inspired Self-assembly of Patterned and Reconfigurable Particles
1Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, 2Department of Chemistry, The Johns Hopkins University
We describe experimental details of the synthesis of patterned and reconfigurable particles from two dimensional (2D) precursors. This methodology can be used to create particles in a variety of shapes including polyhedra and grasping devices at length scales ranging from the micro to centimeter scale.
JoVE Applied Physics
Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM
1Center for Nanoscale Materials, Argonne National Laboratory, 2Institute for Molecular Engineering, University of Chicago
Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution.
JoVE General
Preparation of embryos for Electron Microscopy of the Drosophila embryonic heart tube
1Joint Graduate Program in Cell and Developmental Biology, UMDNJ-Graduate School of Biomedical Sciences and Rutgers: The State University of New Jersey, 2Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey
We describe a process for fixation, embedding, sectioning, and imaging of late stage Drosophila embryos for Trasmission Electron Microscopy of the embryonic heart tube. This technique allows for the visualization of the heart tube lumen as well as the basement membrane, which lines the lumen of the heart.
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