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 General
Testing Protozoacidal Activity of Ligand-lytic Peptides Against Termite Gut Protozoa in vitro (Protozoa Culture) and in vivo (Microinjection into Termite Hindgut)
Department of Entomology, Louisiana State University Agricultural Center
We present procedures for demonstrating that ligands bind to the surface membrane of the cellulose-digesting protozoa in the gut of Formosan subterranean termites using fluorescent microscopy and that ligands coupled with lytic peptides kill these protozoa in vitro (anaerobic protozoa culture) and in vivo (injection into the termite hindgut).
JoVE Applied Physics
Optical Trapping of Nanoparticles
Electrical and Computer Engineering, University of Victoria
The following setup approach details low power optical trapping of dielectric nanoparticles using a double-nanohole in metal film.
JoVE General
Whole-Body Nanoparticle Aerosol Inhalation Exposures
1Department of Physiology and Pharmacology, School of Medicine, West Virginia University, 2Center for Cardiovascular and Respiratory Sciences, West Virginia University, 3National Institute for Occupational Safety and Health
A whole-body nanoparticle aerosol inhalation exposure facility was constructed for nano-sized titanium dioxide (TiO2) inhalation toxicology studies. This system provides nano-TiO2 aerosol test atmospheres that have: 1) a steady mass concentration; 2) a homogenous composition free of contaminants; and 3) a stable particle size distribution during aerosol generation.
JoVE Bioengineering
Evaluation of Polymeric Gene Delivery Nanoparticles by Nanoparticle Tracking Analysis and High-throughput Flow Cytometry
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 Immunology and Infection
Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging
1Experimental and Clinical Research Center, A joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, 2Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine
Tracking of cells using MRI has gained remarkable attention in the past years. This protocol describes the labeling of dendritic cells with fluorine (19F)-rich particles, the in vivo application of these cells, and monitoring the extent of their migration to the draining lymph node with 19F/1H MRI and 19F MRS.
JoVE Clinical and Translational Medicine
Normothermic Cardiac Arrest and Cardiopulmonary Resuscitation: A Mouse Model of Ischemia-Reperfusion Injury
1Department of Anesthesiology and Perioperative Medicine, Oregon Health & Sciences University, 2Department of Pharmacology, University of Colorado Denver
A powerful model for perioperative and critical care related acute kidney injury is presented. Using whole body hypoperfusion induced by cardiac arrest it is possible to nearly replicate the histologic and functional changes of clinical AKI.
JoVE Applied Physics
Determining 3D Flow Fields via Multi-camera Light Field Imaging
1Department of Mechanical Engineering, Brigham Young University, 2Naval Undersea Warfare Center, Newport, RI
A technique for performing quantitative three-dimensional (3D) imaging for a range of fluid flows is presented. Using concepts from the area of Light Field Imaging, we reconstruct 3D volumes from arrays of images. Our 3D results span a broad range including velocity fields and multi-phase bubble size distributions.
JoVE Bioengineering
Viral Nanoparticles for In vivo Tumor Imaging
1Department of Biomedical Engineering, Case Western Reserve University, 2Department of Biomedical Engineering, Radiology, and Materials Science and Engineering, Case Western Reserve University
Plant viral nanoparticles (VNPs) are promising platforms for applications in biomedicine. Here, we describe the procedures for plant VNP propagation, purification, characterization, and bioconjugation. Finally, we show the application of VNPs for tumor homing and imaging using a mouse xenograft model and fluorescence imaging.
JoVE Bioengineering
Micro-particle Image Velocimetry for Velocity Profile Measurements of Micro Blood Flows
1Department of Chemical and Biological Engineering, University of Ottawa, 2Department of Mechanical Engineering, University of Ottawa
Micro-particle image velocimetry (μPIV) is used to visualize paired images of micro particles seeded in blood flows which are cross-correlated to give an accurate velocity profile. Shear rate, maximum velocity, velocity profile shape, and flow rate, each of which has clinical applications, can be derived from these measurements.
JoVE Applied Physics
Compact Quantum Dots for Single-molecule Imaging
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
Localized RNAi and Ectopic Gene Expression in the Medicinal Leech
1Division of Biological Sciences, University of California San Diego - UCSD, 2Department of Physics, University of California San Diego - UCSD
In this video, we show a procedure for an accurate biolistic delivery of reagents into live tissue with a novel miniature gene gun. We are knocking down the expression of the axon guidance molecule Netrin in leech embryos by delivering molecules of dsRNA into the ventral body wall and ganglia of single segments.
JoVE Immunology and Infection
Particle Agglutination Method for Poliovirus Identification
1Department of Virology II, National Institute of Infectious Diseases, 2New Product Design Department, Fujirebio Inc.
A recently developed novel particle agglutination (PA) assay utilizing virus receptor molecule allowed a rapid and easy identification of poliovirus (PV). In this article, we will show the procedure for the PA assay for PV identification.
JoVE Neuroscience
Post-embedding Immunogold Labeling of Synaptic Proteins in Hippocampal Slice Cultures
1Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 2Department of Microbiology and Molecular Genetics, Medical College of Wisconsin
The localization and distribution of proteins provide important information for understanding their cellular functions. The superior spatial resolution of electron microscopy (EM) can be used to determine the subcellular localization of a given antigen following immunohistochemistry. For tissues of the central nervous system (CNS), preserving structural integrity while maintaining antigenicity has been especially difficult in EM studies. Here, we adopt a procedure that has been used to preserve structures and antigens in the CNS to study and characterize synaptic proteins in rat hippocampal CA1 pyramidal neurons.
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 General
Window on a Microworld: Simple Microfluidic Systems for Studying Microbial Transport in Porous Media
1Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, 2Department of Biomedical Engineering, Vanderbilt University, 3Department of Molecular Physiology and Biophysics, Vanderbilt University, 4Department of Physics and Astronomy, Vanderbilt University, 5Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, 6Center for Environmental Sciences and Engineering, University of Connecticut
Microfluidic devices can be used to visualize complex natural processes in real time and at the appropriate physical scales. We have developed a simple microfluidic device that mimics key features of natural porous media for studying growth and transport of bacteria in the subsurface.
JoVE Bioengineering
Cell Co-culture Patterning Using Aqueous Two-phase Systems
1Department of Biomedical Engineering, University of Michigan, 2Department of Macromolecular Science and Engineering, University of Michigan
Aqueous two-phase systems were used to simultaneously pattern multiple populations of cells. This fast and easy method for cell patterning takes advantage of the phase separation of aqueous solutions of dextran and polyethylene glycol and the interfacial tension that exists between the two polymer solutions.
JoVE General
Primer Extension Capture: Targeted Sequence Retrieval from Heavily Degraded DNA Sources
Max-Planck Institute for Evolutionary Anthropology, Leipzig
We present a method of targeted ancient DNA sequence retrieval, which we used to reconstruct the complete mitochondrial genomes of five Neandertal individuals. Comparison of these sequences with present day humans suggests that Neandertals had a long term low effective population size.
JoVE General
Generation of Transgenic C. elegans by Biolistic Transformation
Department of Medicine, University of Pittsburgh
Transgenic worms are commonly used in C. elegans research. Described is a simple, yet effective, protocol to introduce transgenes into worms using biolistic bombardment with DNA-coated gold particles. The effort involved and results of bombardment compare favorably with microinjection for the generation of transgenic animals.
JoVE General
Profiling of Methyltransferases and Other S-adenosyl-L-homocysteine-binding Proteins by Capture Compound Mass Spectrometry (CCMS)
1Department of Biochemistry / Analytics, caprotec bioanalytics GmbH, 2Institute of Organic Chemistry, RWTH Aachen University
Capture Compounds are trifunctional small molecules to reduce the complexity of the proteome by functional reversible small molecule-protein interaction followed by photo-crosslinking and purification. Here we use a Capture Compound with S-adenosyl-L-homocysteine-binding as selectivity function to isolate methyltransferases from an Escherichia coli whole cell lysate and identify them by MS.
JoVE Immunology and Infection
Packaging HIV- or FIV-based Lentivector Expression Constructs & Transduction of VSV-G Pseudotyped Viral Particles
Lentiviral expression vectors are the most effective vehicles for stably expressing different effector molecules or reporter constructs in dividing and non-dividing mammalian cells and whole organisms. Here we provide a protocol on how to package lentivector expression constructs in pseudoviral particles and to transduce target cells using the pseudoviral particles.
JoVE General
Annotation of Plant Gene Function via Combined Genomics, Metabolomics and Informatics
Molekulare Pflanzenphysiologie, Max-Planck-Institut
Combination of genomics, co-expression gene analysis and the identification of target compounds via metabolism give gene functional annotation.
JoVE Applied Physics
Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles
Department of Chemical Engineering, The Pennsylvania State University
We have used plasma enhanced chemical vapor deposition to deposit thin films ranging from a few nm to several 100 nm on nano-sized particles of various materials. We subsequently etch the core material to produce hollow nanoshells whose permeability is controlled by the thickness of the shell. We characterize the permeability of these coatings to small solutes and demonstrate that these barriers can provide sustained release of the core material over several days.
JoVE General
Characterization of the Isolated, Ventilated, and Instrumented Mouse Lung Perfused with Pulsatile Flow
Department of Biomedical Engineering, University of Wisconsin – Madison
The following protocol outlines the process of isolating, ventilating and instrumenting mouse lungs to measure steady or pulsatile pulmonary vascular pressure-flow relationships in order to quantify the effects of blood flow, airflow, airway changes and vascular changes on right ventricular afterload.
JoVE Applied Physics
Echo Particle Image Velocimetry
Mechanical Engineering Department, University of New Hampshire
An echo particle image velocimetry (EPIV) system capable of acquiring two-dimensional fields of velocity in optically opaque fluids or through optically opaque geometries is described, and validation measurements in pipe flow are reported.
JoVE Chemistry
Untargeted Metabolomics from Biological Sources Using Ultraperformance Liquid Chromatography-High Resolution Mass Spectrometry (UPLC-HRMS)
Untargeted metabolomics provides a hypothesis generating snapshot of a metabolic profile. This protocol will demonstrate the extraction and analysis of metabolites from cells, serum, or tissue. A range of metabolites are surveyed using liquid-liquid phase extraction, microflow ultraperformance liquid chromatography/high-resolution mass spectrometry (UPLC-HRMS) coupled to differential analysis software.
JoVE General
Visualization of Caenorhabditis elegans Cuticular Structures Using the Lipophilic Vital Dye DiI
We present a method to visualize cuticle in live C. elegans using the red fluorescent lipophilic dye DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate), which is commonly used in C. elegans to visualize environmentally exposed neurons. With this optimized protocol, alae and annular cuticular structures are stained by DiI and observed using compound microscopy.
JoVE Immunology and Infection
Growth of Mycobacterium tuberculosis Biofilms
1Department of Infectious Diseases and Microbiology, University of Pittsburgh, 2Department of Biological Sciences, University of Pittsburgh
Mycobacterium tuberculosis forms drug tolerant biofilms when cultured in certain conditions. Here we describe methods for culturing M. tuberculosis biofilms and determining the frequency of drug tolerant persisters. These protocols will be useful for further studies into the mechanisms of drug tolerance in M. tuberculosis.
JoVE Chemistry
Template Directed Synthesis of Plasmonic Gold Nanotubes with Tunable IR Absorbance
Department of Chemistry, University of Toronto
Solution-suspendable gold nanotubes with controlled dimensions can be synthesized by electrochemical deposition in porous anodic aluminum oxide (AAO) membranes using a hydrophobic polymer core. Gold nanotubes and nanotube arrays hold promise for applications in plasmonic biosensing, surface-enhanced Raman spectroscopy, photo-thermal heating, ionic and molecular transport, microfluidics, catalysis and electrochemical sensing.
JoVE Bioengineering
Air Filter Devices Including Nonwoven Meshes of Electrospun Recombinant Spider Silk Proteins
Biomaterials Research Group, University of Bayreuth
Spider silk fibers display extraordinary mechanical properties. Engineered Araneus diadematus Fibroin 4 (eADF4) can be processed into nonwoven meshes using electrospinning. Here, the eADF4 nonwoven meshes are used to improve the performance of air filtering devices.
JoVE Bioengineering
A Microfluidic-based Hydrodynamic Trap for Single Particles
1Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, 2Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign
In this article, we present a microfluidic-based method for particle confinement based on hydrodynamic flow. We demonstrate stable particle trapping at a fluid stagnation point using a feedback control mechanism, thereby enabling confinement and micromanipulation of arbitrary particles in an integrated microdevice.
JoVE General
Method for Measurement of Viral Fusion Kinetics at the Single Particle Level
1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 2Howard Hughes Medical Institute, Harvard Medical School
We present an in vitro, two-color fluorescence assay to visualize the fusion of single virus particles with a fluid target bilayer. By labeling viral particles with fluorophores that differentially stain the viral membrane and its interior, we are able to monitor the kinetics of hemifusion and pore formation.
JoVE Clinical and Translational Medicine
Method for Novel Anti-Cancer Drug Development using Tumor Explants of Surgical Specimens
1Department of Neurological Surgery, The Ohio State University Medical Center, 2Department of Pathology, The Ohio State University Medical Center
Here, we established a method for drug efficacy testing with surgical specimens of brain tumors, termed “tumor explant method”. With this method, we can evaluate drug efficacy without breaking the microenvironment of solid tumors. To validate reliability of this method, we describe representative data with our glioma specimen treated with the current first-line chemotherapeutic agent, temozolomide.
JoVE General
Visualization of Endoplasmic Reticulum Localized mRNAs in Mammalian Cells
Department of Biochemistry, University of Toronto
Here we describe a method to visualize endoplasmic reticulum-associated mRNAs in mammalian tissue culture cells. This technique involves the selective permeabilization of the plasma membrane with digitonin to remove cytoplasmic contents followed by fluorescent in situ hybridization to detect either bulk poly(A) mRNA or specific transcripts.
JoVE Bioengineering
Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus (SCUVA)
1Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, 2Environmental Science and Marine Biology, Roger Williams University, 3Marine Biology Laboratory, Whitman Center, 4Department of Biology, Providence College, 5Departments of Aeronautics and Bioengineering, California Institute of Technology
This protocol provides instructions on how to use a self-contained underwater velocimetry apparatus (SCUVA), which is designed for quantification of in situ animal-generated flows. In addition, this protocol addresses challenges posed by field conditions, and includes operator motion, predicting position of animals, and orientation of SCUVA.
JoVE Bioengineering
Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation
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 General
Determination of Mammalian Cell Counts, Cell Size and Cell Health Using the Moxi Z Mini Automated Cell Counter
1Orflo Technologies, 2University of Utah
The Moxi Z miniature automated cell counter is a novel instrument that combines the Coulter Principle with patented thin-film sensor technology and a proprietary software algorithm to perform sizing and counting of a broad size range of particles as well as to determine the overall health of monodisperse mammalian cell cultures. This protocol describes the use of this instrument for counting and assessing the health of cell cultures.
JoVE General
Generation of Mice Derived from Induced Pluripotent Stem Cells
1Dorris Neuroscience Center & Department of Cell Biology, The Scripps Research Institute, 2Mouse Genetics Core Facility, The Scripps Research Institute
Generating induced pluripotent stem cell (iPSC) lines produces lines of differing developmental potential even when they pass standard tests for pluripotency. Here we describe a protocol to produce mice derived entirely from iPSCs, which defines the iPSC lines as possessing full pluripotency1.
JoVE Chemistry
Preparation and Use of Samarium Diiodide (SmI2) in Organic Synthesis: The Mechanistic Role of HMPA and Ni(II) Salts in the Samarium Barbier Reaction
Department of Chemistry, Lehigh University
A straightforward procedure for the preparation of samarium diiodide (SmI2) in THF is described. The role of two main additives namely hexamethylphosphoramide (HMPA) and Ni(acac)2 in Sm mediated reactions is demonstrated in the Sm-Barbier reaction.
JoVE General
Single Particle Electron Microscopy Reconstruction of the Exosome Complex Using the Random Conical Tilt Method
Molecular Biophysics and Biochemistry, Yale University
This article describes a standard method to get a three-dimensional (3D) reconstruction of biological macromolecules using negative staining electron microscopy (EM). In this protocol, we explain how to get the 3D structure of the Saccharomyces cerevisiae exosome complex at medium resolution using the random conical tilt reconstruction method (RCT).
JoVE General
AC Electrokinetic Phenomena Generated by Microelectrode Structures
1Biomedical Engineering, Science and Health Systems, Drexel University, 2Mechanical Engineering and Mechanics, Drexel University
Manipulating fluids and suspended particles in the micro- and nano-scale is becoming more of a reality as enabling technologies, like AC electrokinetics, continue to develop. Here, we discuss the physics behind AC electrokinetics, how to fabricate these devices and how to interpret the experimental observations.
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 Immunology and Infection
Customization of Aspergillus niger Morphology Through Addition of Talc Micro Particles
Institute of Biochemical Engineering, Technische Universität Braunschweig
A method to precisely generate and to comprehensively characterize morphology of filamentous fungus Aspergillus niger is described, which allows the mathematical correlation of morphological appearance and productivity.
JoVE General
Chemotactic Response of Marine Micro-Organisms to Micro-Scale Nutrient Layers
Environmental Microfluidics Group, MIT - Massachusetts Institute of Technology
The fabrication of microfluidic channels and their implementation in experiments for studying the chemotactic foraging behaviour of marine microbes within a patchy nutrient seascape and the swimming behaviour of bacteria within shear flow are described.
JoVE Bioengineering
High Throughput Single-cell and Multiple-cell Micro-encapsulation
Department of Mechanical Engineering, Vanderbilt University
Combining monodisperse drop generation with inertial ordering of cells and particles, we describe a method to encapsulate a desired number of cells or particles in a single drop at kHz rates. We demonstrate efficiencies twice exceeding those of unordered encapsulation for single- and double-particle drops.
JoVE Clinical and Translational Medicine
Non-invasive Imaging of Acute Allograft Rejection after Rat Renal Transplantation Using 18F-FDG PET
1Department of Internal Medicine D, Experimental Nephrology, University of Münster, 2Department of Nuclear Medicine, University of Münster, 3European Institute for Molecular Imaging, University of Münster
We herein present a rat renal transplantation model to non-invasively assess acute allograft rejection using positron emission tomography with 18F-fluorodeoxyglucose.
JoVE General
Isolation and Enrichment of Rat Mesenchymal Stem Cells (MSCs) and Separation of Single-colony Derived MSCs
Department of Chemical Engineering and Materials Science, City of Hope Cancer Center
Rat MSCs were isolated from femurs and tibias and then enriched by magnetic cell sorting. Sorted cells were confirmed for the expression of surface markers by flow cytometry. These cells were also cultured at clonal density to form single colonies and then these colonies were separated by cloning cylinders.
JoVE General
Preparation of Gene Gun Bullets and Biolistic Transfection of Neurons in Slice Culture
Center for Neuroscience, University of California, Davis
We describe a method for preparing DNA coated gold bullets and demonstrate the use of such bullets to biolistically transfect neurons in cultured hippocampal slices.
JoVE General
IP-FCM: Immunoprecipitation Detected by Flow Cytometry
Department of Immunology, College of Medicine, Mayo Clinic
The IP-FCM method is presented, which allows a sensitive, robust, biochemical assessment of native protein-protein interactions, without requiring genetic engineering or large sample sizes.
JoVE General
Isolation and Culture of Pulmonary Endothelial Cells from Neonatal Mice
Blood Research Institute, BloodCenter of Wisconsin
Here, we describe a protocol for isolation and culture of murine pulmonary endothelial cells. This method comprises mechanic and enzymatic lung tissue dissociation as well as a 2-step purification process using anti-PECAM-1 and anti-ICAM-2 antibodies conjugated to magnetic beads, which produces a pure endothelial cell population of mostly microvascular origin.
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