The Journal of Visualized Experiments (JoVE) is a peer reviewed, PubMed-indexed video journal. Our mission is to increase the productivity of scientific research.

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 JoVE Applied Physics

Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation


JoVE 4308 9/13/2012

Department of Mechanical Engineering, Boston University

Phase-shift nanoemulsions (PSNE) can be vaporized using high intensity focused ultrasound to enhance localized heating and improve thermal ablation in tumors. In this report, the preparation of stable PSNE with a narrow size distribution is described. Furthermore, the impact of vaporized PSNE on ultrasound-mediated ablation is demonstrated in tissue-mimicking phantoms.

 JoVE Bioengineering

Small and Wide Angle X-Ray Scattering Studies of Biological Macromolecules in Solution


JoVE 4160 1/08/2013

Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute

The demonstration of the small and wide angle X-ray scattering (SWAXS) procedure has become instrumental in the study of biological macromolecules. Through the use of the instrumentation and procedures of specific angle methods and preparation, the experimental data from the SWAXS displays the atomic and nano-scale characterization of macromolecules.

 JoVE Applied Physics

Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping


JoVE 4092 7/02/2012

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

Constant Pressure-controlled Extrusion Method for the Preparation of Nano-sized Lipid Vesicles


JoVE 4151 6/22/2012

1Department of Chemistry & Biochemistry, University of Colorado Boulder, 2Biofrontiers Institute, University of Colorado Boulder

This protocol describes an extrusion method for preparing lipid vesicles of sub-micron sizes with a high degree of homogeneity. This method uses a pressure-controlled system with controlled nitrogen flow rates for liposome preparation. The lipid preparation1,2, liposome extrusion, and size characterization will be presented herein.

 JoVE Clinical and Translational Medicine

Non-invasive Optical Measurement of Cerebral Metabolism and Hemodynamics in Infants


JoVE 4379 3/14/2013

1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, 2Lab. PALM, Université de Caen Basse-Normandie, 3Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Harvard Medical School, 4ISS, INC.

We combined frequency-domain near-infrared spectroscopy measures of cerebral hemoglobin oxygenation with diffuse correlation spectroscopy measures of cerebral blood flow index to estimate an index of oxygen metabolism. We tested the utility of this measure as a bedside screening tool to evaluate the health and development of the newborn brain.

 JoVE Applied Physics

Fabrication of Nano-engineered Transparent Conducting Oxides by Pulsed Laser Deposition


JoVE 50297 2/27/2013

1Department of Energy and NEMAS - Center for NanoEngineered Materials and Surfaces, Politecnico di Milano, 2Center for Nano Science and Technology, Instituto Italiano di Tecnologia

We describe the experimental method to deposit nanostructured oxide thin films by nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas. By using this method Al-doped ZnO (AZO) films, from compact to hierarchically structured as nano-tree forests, can be deposited.

 JoVE Bioengineering

Rejection of Fluorescence Background in Resonance and Spontaneous Raman Microspectroscopy


JoVE 2592 5/18/2011

1Center for Biophotonics Science and Technology, University of California, Davis, 2Department of Pathology and Laboratory Medicine, University of California, Davis

We discuss the construction and operation of a complex nonlinear optical system that uses ultrafast all-optical switching to isolate Raman from fluorescence signals. Using this system we are able to successfully separate Raman and fluorescence signals utilizing pulse energies and average powers that remain biologically safe.

 JoVE Bioengineering

Evaluation of Polymeric Gene Delivery Nanoparticles by Nanoparticle Tracking Analysis and High-throughput Flow Cytometry


JoVE 50176 3/01/2013

1Biomedical Engineering Department, Johns Hopkins University School of Medicine, 2Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, 3Wilmer Eye Institute, Johns Hopkins University School of Medicine, 4Institute for Nanobiotechnology, Johns Hopkins University School of Medicine

A protocol for nanoparticle tracking analysis (NTA) and high-throughput flow cytometry to evaluate polymeric gene delivery nanoparticles is described. NTA is utilized to characterize the nanoparticle particle size distribution and the plasmid per particle distribution. High-throughput flow cytometry enables quantitative transfection efficacy evaluation for a library of gene delivery biomaterials.

 JoVE General

Synthesis of an In vivo MRI-detectable Apoptosis Probe


JoVE 3775 7/31/2012

1Division of Cardiovascular Medicine, Department of Medicine, Stanford University Medical Center, 2Division of Cardiology, Department of Medicine, University of California, San Francisco, 3San Francisco VAMC

Early detection of apoptosis may identify at-risk cell populations in a variety of diseases. Here we demonstrate a method to link an early apoptosis-detection protein (Annexin V) to a MRI-detectable iron oxide nanoparticle (SPIO). This method may be extended to other proteins of interest to generate MRI-detectable molecular imaging probes.

 JoVE Clinical and Translational Medicine

Quantifying Glomerular Permeability of Fluorescent Macromolecules Using 2-Photon Microscopy in Munich Wistar Rats


JoVE 50052 4/17/2013

Medicine/Nephrology, Indiana University School of Medicine

A technique utilizing high resolution intavital 2-photon microscopy to directly visualize and quantify gloemrular filtration in surface glomeruli. This method allows for direct determination of permeability characteristics of macromolecules in both normal and diseased states.

 JoVE Immunology and Infection

Basophil Activation Test for Investigation of IgE-Mediated Mechanisms in Drug Hypersensitivity


JoVE 3263 9/16/2011

1Department of Molecular Biology, University of Salzburg, 2Department of Neurology, Paracelsus Medical University, 3Department of Dermatology, Paracelsus Medical University, 4Bühlmann Laboratories, 5Christian Doppler Laboratory for Allergy Diagnosis and Therapy, University of Salzburg

Basophil activation test is a potent tool for the detection of IgE-dependent allergies in vitro. Here, an optimized protocol for basophil activation test is used to investigate drug hypersensitivity. A method for the efficient production of covalent drug-protein conjugates and their physicochemical characterization is described.

 JoVE Bioengineering

High-throughput Synthesis of Carbohydrates and Functionalization of Polyanhydride Nanoparticles


JoVE 3967 7/06/2012

1Department of Chemical and Biological Engineering, Iowa State University, 2Department of Chemistry, Iowa State University

In this article, a high throughput method is presented for the synthesis of oligosaccharides and their attachment to the surface of polyanhydride nanoparticles for further use in targeting specific receptors on antigen presenting cells.

 JoVE Applied Physics

A Method to Fabricate Disconnected Silver Nanostructures in 3D


JoVE 4399 11/27/2012

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

Three-dimensional Optical-resolution Photoacoustic Microscopy


JoVE 2729 5/03/2011

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 General

Tangential Flow Ultrafiltration: A “Green” Method for the Size Selection and Concentration of Colloidal Silver Nanoparticles


JoVE 4167 10/04/2012

1Department of Chemistry, Wright State University, 2Department of Neuroscience, Cell Biology, and Physiology, Wright State University

Tangential flow ultrafiltration (TFU) is a recirculation method used for the weight-based separation of biosamples. TFU was adapted to size-select (1-20 nm diameter) and highly concentrate a large volume of polydisperse silver nanoparticles (4 L of 15.2 μg ml-1 down to 4 ml of 8,539.9 μg ml-1) with minimal aggregation.

 JoVE General

Biochemical and High Throughput Microscopic Assessment of Fat Mass in Caenorhabditis Elegans


JoVE 50180 3/30/2013

1Center for Human Genetic Research and Department of Medicine, Massachusetts General Hospital and Harvard Medical School, 2Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology

We present robust biochemical and microscopic methods for studying Caenorhabditis elegans lipid stores. A rapid, simple, fixing-staining procedure for fluorescent lipid droplet imaging leverages the spectral properties of the lipophilic dye Nile red. We then present biochemical measurement of triglycerides and phospholipids using solid phase extraction and gas chromatography-mass spectrometry.

 JoVE Bioengineering

Quantitative Locomotion Study of Freely Swimming Micro-organisms Using Laser Diffraction


JoVE 4412 10/25/2012

1Physics & Astronomy Department, Vassar College, 2Biology Department, Vassar College

Microscopic organisms like the free-swimming nematode C. elegans, live and behave in a complex three-dimensional environment. We report on a novel approach that provides analysis of C. elegans using diffraction patterns. This approach consists of tracking the temporal periodicity of diffraction patterns generated by directing laser light through a cuvette.

 JoVE Applied Physics

Bringing the Visible Universe into Focus with Robo-AO


JoVE 50021 2/12/2013

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 General

Differential Imaging of Biological Structures with Doubly-resonant Coherent Anti-stokes Raman Scattering (CARS)


JoVE 2085 10/17/2010

1Center for Biophotonics, University of California, Davis, 2Department of Internal Medicine, University of California, Davis

A combination of three single wavelength short-pulsed lasers is used to generate coherent anti-Stokes Raman scattering (CARS) and doubly-resonant CARS (DR-CARS). The difference between these signals provides enhanced sensitivity for otherwise difficult to detect coherent Raman signals, enabling imaging of weak Raman scatterers.

 JoVE Applied Physics

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water


JoVE 3975 8/02/2012

1Organic Chemistry Institute and CeNTech, Westfälische Wilhelms-Universität Münster, 2Laboratory of Macromolecular and Organic Chemistry, Institute for Complex Molecular Systems, Eindhoven University of Technology, 3Laboratory of Materials and Interface Chemistry and Soft Matter Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology

The goal of this experiment is to determine and control the size, shape and stability of self-assembled discotic amphiphiles in water. For aqueous based supramolecular polymers such level of control is very difficult. We apply a strategy using both repulsive and attractive interactions. The experimental techniques applied to characterize this system are broadly applicable.

 JoVE General

Use of Arabidopsis eceriferum Mutants to Explore Plant Cuticle Biosynthesis


JoVE 709 5/31/2008

1Department of Botany, University of British Columbia - UBC, 2Department of Chemistry, University of British Columbia - UBC

The plant cuticle is a waxy outer covering on plants that has a primary role in water conservation but is also an important barrier against the entry of pathogenic microorganisms. In this video, we demonstrate the analysis of plant cuticle mutants identified by forward and reverse genetics approaches.

 JoVE Bioengineering

Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation


JoVE 3390 9/27/2011

1Electrical Engineering Department, University of Washington, 2Division of Human Biology, Fred Hutchinson Cancer Research Center, 3Molecular and Cellular Biology Program, University of Washington, 4Clinical Research, Fred Hutchinson Cancer Research Center, 5Public Health Sciences, Fred Hutchinson Cancer Research Center

Plasmonic tweezers and photonic crystal nanostructures are shown to produce useful enhancements in the efficiency and orientation control of optically trapping micro- and nano-particles.

 JoVE Neuroscience

A Polished and Reinforced Thinned-skull Window for Long-term Imaging of the Mouse Brain


JoVE 3742 3/07/2012

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 Applied Physics

Compact Quantum Dots for Single-molecule Imaging


JoVE 4236 10/09/2012

1Department of Biomedical Engineering, Emory University, 2Department of Chemistry, Georgia Institute of Technology

We describe the preparation of colloidal quantum dots with minimized hydrodynamic size for single-molecule fluorescence imaging. Compared to conventional quantum dots, these nanoparticles are similar in size to globular proteins and are optimized for single-molecule brightness, stability against photodegradation, and resistance to nonspecific binding to proteins and cells.

 JoVE General

Born Normalization for Fluorescence Optical Projection Tomography for Whole Heart Imaging


JoVE 1389 6/02/2009

1Center for Systems Biology, Harvard Medical School, 2Center for Systems Biology, MGH - Massachusetts General Hospital, 3Institute for Biological and Medical Imaging, Technical University of Munich and Helmholtz Center Munich

We suggest a Born normalized approach for Optical Projection Tomography (BnOPT) that accounts for the absorption properties of imaged samples to obtain accurate and quantitative fluorescence tomographic reconstructions. We use the proposed algorithm to reconstruct the fluorescence molecular probe distribution within small animal organs.

 JoVE General

Label-free in situ Imaging of Lignification in Plant Cell Walls


JoVE 2064 11/01/2010

1Energy Biosciences Institute, University of California, Berkeley, 2Molecular Foundry, Lawrence Berkeley National Laboratory, 3Physical Biosciences Division, Lawrence Berkeley National Laboratory

A method based on confocal Raman microscopy is presented that affords label-free visualization of lignin in plant cell walls and comparison of lignification in different tissues, samples or species.

 JoVE Neuroscience

Thinned-skull Cortical Window Technique for In Vivo Optical Coherence Tomography Imaging


JoVE 50053 11/19/2012

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 Immunology and Infection

Analysis of the Solvent Accessibility of Cysteine Residues on Maize rayado fino virus Virus-like Particles Produced in Nicotiana benthamiana Plants and Cross-linking of Peptides to VLPs


JoVE 50084 2/14/2013

1Plant Sciences Institute, Agricultural Research Service, United States Department of Agriculture, 2Molecular Plant Pathology Laboratory, Agricultural Research Service, United States Department of Agriculture

A method to analyze the solvent accessibility of the thiol group of cysteine residues of Maize rayado fino virus (MRFV)-virus-like particles (VLPs) followed by a peptide cross-linking reaction is described. The method takes advantage of the availability of several chemical groups on the surface of the VLPs that can be targets for specific reactions.

 JoVE Immunology and Infection

Non-invasive Imaging of Leukocyte Homing and Migration in vivo


JoVE 2062 12/05/2010

1Department of Pathology and Immunology, Washington University in St. Louis, 2National Institute of Neurological Disorders and Stroke, NINDS, NIH - National Institute of Health

Here, we describe a non-invasive two-photon (2P) microscopy approach to study leukocyte homing in the mouse footpad. We discuss the technical aspects of our tissue imaging preparation and walk the reader through a typical experiment from initial set up to execution and data collection.

 JoVE General

Dendra2 Photoswitching through the Mammary Imaging Window


JoVE 1278 6/05/2009

1Department of Anatomy and Structural Biology, Albert Einstein College of Medicine - Yeshiva University, 2Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine - Yeshiva University, 3Hubrecht Institute-KNAW and University Medical Center Utrecht

Intravital photoswitching and tracking of Dendra2-labeled tumor cells through the Mammary Imaging Window is a technique which allows us to image the metastatic behavior of tumor cells in chosen tumor microenvironments over a timescale of days.

 JoVE General

Multi-parameter Measurement of the Permeability Transition Pore Opening in Isolated Mouse Heart Mitochondria


JoVE 4131 9/07/2012

Department of Anesthesiology & Pain Medicine, Mitochondria and Metabolism Center, University of Washington, Seattle

A spectrofluorometric protocol for the measurement of the mitochondrial permeability transition pore opening in isolated mouse heart mitochondria is presented here. The assay involves the simultaneous measurement of mitochondria Ca2+ handling, mitochondrial membrane potential and mitochondrial volume. The procedure for obtaining high-quality and functional heart mitochondria is also described.

 JoVE General

Dissection and 2-Photon Imaging of Peripheral Lymph Nodes in Mice


JoVE 265 8/23/2007

1Department of Physiology and Biophysics, University of California, Irvine (UCI), 2Department of Neurobiology and Behaviour, University of California, Irvine (UCI)

Two-photon imaging has uncovered lymphocyte motility and cellular interactions within the lymph node under basal conditions and durring an immune response 1. Here, we demonstrate adoptive transfer of T cells, isolation of lymph nodes, and imaging motility of CD4+ T cells in the explanted lymph node.

 JoVE General

Tracking Dynamics of Muscle Engraftment in Small Animals by In Vivo Fluorescent Imaging


JoVE 1388 9/21/2009

1Department of Anesthesia, Brigham and Woman's Hospital, 2Department of Radiology, Brigham and Woman's Hospital

We describe an in vivo fluorescence imaging protocol to monitor muscle regeneration by GFP-labeled myoblasts after transplantation into skeletal muscles of both healthy and dystrophic mice. This protocol can be adapted to study muscle regeneration by transplantation of other types of cells and in other muscular conditions as well.

 JoVE Clinical and Translational Medicine

Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain


JoVE 4204 8/28/2012

1Department of Surgery, University of Texas Medical Branch, 2Department of Neuroscience and Cell Biology, University of Texas Medical Branch

A method for large-scale purification of the APP intracellular domain (AICD) is described. We also describe methodology to induce in vitro AICD aggregation and visualization by atomic force microscopy. The methods described are useful for biochemical/structural characterization of the AICD and the effects of molecular chaperones on its aggregation.

 JoVE Neuroscience

Voltage-sensitive Dye Recording from Axons, Dendrites and Dendritic Spines of Individual Neurons in Brain Slices


JoVE 4261 11/29/2012

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 Bioengineering

Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography


JoVE 4390 1/15/2013

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 General

Mesoscopic Fluorescence Tomography for In-vivo Imaging of Developing Drosophila


JoVE 1510 8/20/2009

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

Exploring Cognitive Functions in Babies, Children & Adults with Near Infrared Spectroscopy


JoVE 1268 7/28/2009

1Department of Psychology, University of Michigan, Ann Arbor, 2Department of Psychology, University of Toronto Scarborough

Here we describe a data collection and data analysis method for functional Near Infrared Spectroscopy (fNIRS), a novel non-invasive brain imaging system used in cognitive neuroscience, particularly in studying child brain development. This method provides a universal standard of data acquisition and analysis vital to data interpretation and scientific discovery.

 JoVE Bioengineering

Formulation of Diblock Polymeric Nanoparticles through Nanoprecipitation Technique


JoVE 3398 9/20/2011

1Laboratory of Nano- and Translational Medicine, Department of Radiation Oncology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, 2Carolina Center for Nanotechnology Excellence, University of North Carolina

This article describes a nanoprecipitation method to synthesize polymer-based nanoparticles using diblock co-polymers. We will discuss the synthesis of diblock co-polymers, the nanoprecipitation technique, and potential applications.

 JoVE Bioengineering

Optical Frequency Domain Imaging of Ex vivo Pulmonary Resection Specimens: Obtaining One to One Image to Histopathology Correlation


JoVE 3855 1/22/2013

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.

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