JoVE Bioengineering
Planar and Three-Dimensional Printing of Conductive Inks
1Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 2Center for Micro- and Nanotechnology, Lawrence Livermore National Laboratory, 3Presently at the Interdisciplinary Center for Wide Band-gap Semiconductors, University Of California Santa Barbara
Planar and three-dimensional printing of conductive metallic inks is described. Our approach provides new avenues for fabricating printed electronic, optoelectronic, and biomedical devices in unusual layouts at the microscale.
JoVE Bioengineering
Design of a Biaxial Mechanical Loading Bioreactor for Tissue Engineering
1Department of Orthopaedics, The Warren Alpert Brown Medical School of Brown University and the Rhode Island Hospital, 2Center for Restorative and Regenerative Medicine, VA Medical Center, Providence, RI, 3University of Texas Southwestern Medical Center
We designed a novel mechanical loading bioreactor that can apply uniaxial or biaxial mechanical strain to a cartilage biocomposite prior to transplantation into an articular cartilage defect.
JoVE Bioengineering
Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging
1Department of Radiology and Biomedical Imaging, University of California, San Francisco, 2School of Medicine, University of California, San Francisco, 3Department of Radiology and Biomedical Imaging, UCSF Medical Center, 4University of California, San Francisco, 5Hansen Medical, Mountain View, CA
Current applied to an endovascular microcatheter with microcoil tip made by laser lathe lithography can achieve controllable deflections under magnetic resonance (MR) guidance, which may improve speed and efficacy of navigation of vasculature during various endovascular procedures.
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 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 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 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 General
Measuring Plant Cell Wall Extension (Creep) Induced by Acidic pH and by Alpha-Expansin
Department of Biology, Penn State University
We demonstrate the use of a constant-force extensometer to measure long-term extension (creep) of plant cell wall specimens induced by acidic buffers and expansin protein.
JoVE Neuroscience
Electrode Fabrication and Implantation in Aplysia californica for Multi-channel Neural and Muscular Recordings in Intact, Freely Behaving Animals
1Biology, Case Western Reserve University, 2Neurosciences, Case Western Reserve University, 3Biomedical Engineering, Case Western Reserve University
A technique is described for implanting four in vivo electrodes to monitor the neuromuscular control of feeding behavior in Aplysia californica.
JoVE Bioengineering
Directed Cellular Self-Assembly to Fabricate Cell-Derived Tissue Rings for Biomechanical Analysis and Tissue Engineering
Biomedical Engineering Department, Worcester Polytechnic Institute
This article outlines a versatile method to create cell-derived tissue rings by cellular self-assembly. Smooth muscle cells seeded into ring-shaped agarose wells aggregate and contract to form robust three-dimensional (3D) tissues within 7 days. Millimeter-scale tissue rings are conducive to mechanical testing and serve as building blocks for tissue assembly.
JoVE General
Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Howard Hughes Medical Institute, Rockefeller University
The fate of the replisome following a collision with a head-on RNA polymerase (RNAP) is unknown. We find that the replisome stalls upon collision with a head-on RNAP, but resumes elongation after displacing the RNAP from DNA. Mfd promotes replication restart by facilitating displacement of the RNAP after the collision.
JoVE General
Born Normalization for Fluorescence Optical Projection Tomography for Whole Heart Imaging
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 Neuroscience
Fiber-optic Implantation for Chronic Optogenetic Stimulation of Brain Tissue
1Department of Molecular & Human Genetics, Baylor College of Medicine (BCM), 2Department of Neuroscience, Baylor College of Medicine (BCM), 3Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital
The development of optogenetics now provides the means to precisely stimulate genetically defined neurons and circuits, both in vitro and in vivo. Here we describe the assembly and implantation of a fiber optic for chronic photostimulation of brain tissue.
JoVE Neuroscience
Correlating Behavioral Responses to fMRI Signals from Human Prefrontal Cortex: Examining Cognitive Processes Using Task Analysis
1Department of Psychology, Centre for Vision Research, York University, 2Department of Biology, Centre for Vision Research, York University
The goal of our research is to correlate behavior to brain activity. Accurate behavioral measures and imaging techniques allow us to elucidate brain-behavior relationships.
JoVE General
Derivation of Human Embryonic Stem Cells by Immunosurgery
Department of Molecular and Cell Biology, Harvard
The ability of human embryonic stem cells to self-renew and differentiate into all cell types of the body suggests that they hold great promise for both medical applications and as a research tool for addressing fundamental questions in development and disease. Here, we provide a concise, step-by-step protocol for the derivation of human embryonic stem cells from embryos by immunosurgical isolation of the inner cell mass.
JoVE General
Mutagenesis and Functional Analysis of Ion Channels Heterologously Expressed in Mammalian Cells
Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies
We will demonstrate how to study the effect of a single point mutation on the function of an ion channel.
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 General
Preparation and Using Phantom Lesions to Practice Fine Needle Aspiration Biopsies
1Department of Pathology, University of Wisconsin - Milwaukee, 2BioInnovation LLC
Practicing of fine needle aspiration biopsies (FNAB) by trainees is relatively challenging, due to the lack of an easily available, appropriate lesion. Preparation of an AV phantom lesion for practicing the FNAB procedure and mastering proficiency is relatively easy.
JoVE General
High-throughput Saccharification Assay for Lignocellulosic Materials
Center for Novel Agricultural Products, University of York
A simple, rapid method for determining the saccharification potential of large numbers of plant biomass samples is described. The automated platform for this analysis involves the preparation of the plant biomass for analysis in 96 well plates and the subsequent performance of pretreatment, hydrolysis and quantification of the sugars released.
JoVE General
Combining QD-FRET and Microfluidics to Monitor DNA Nanocomplex Self-Assembly in Real-Time
1Mechanical Engineering, Johns Hopkins University, 2Biomedical Engineering, Duke University, 3Biomedical Engineering, Johns Hopkins University
We present a novel and powerful integration of nanophotonics (QD-FRET) and microfluidics to investigate the formation of polyelectrolyte polyplexes, which is expected to provide better control and synthesis of uniform and customizable polyplexes for future nucleic acid-based therapeutics.
JoVE Clinical and Translational Medicine
Portable Intermodal Preferential Looking (IPL): Investigating Language Comprehension in Typically Developing Toddlers and Young Children with Autism
Department of Psychology, University of Connecticut
A reliable home-based way to assess the language comprehension of very young typically developing children, as well as those with autism, is described. The method analyzes children's eye gaze while viewing side-by-side images but hearing an audio that matches only one image. Stimuli are designed with young participants in mind.
JoVE Bioengineering
Creating Two-Dimensional Patterned Substrates for Protein and Cell Confinement
Department of Chemistry, Washington University in St. Louis
Self-assembled monolayers (SAMs) formed from long chain alkane thiols on gold provide well-defined substrates for the formation of protein patterns and cell confinement. Microcontact printing of hexadecanethiol using a polydimethylsiloxane (PDMS) stamp followed by backfilling with a glycol-terminated alkane thiol monomer produces a pattern where protein and cells adsorb only to the stamped hexadecanethiol region.
JoVE Bioengineering
Separating Beads and Cells in Multi-channel Microfluidic Devices Using Dielectrophoresis and Laminar Flow
1Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 2Micro and Nanotechnology Lab, University of Illinois at Urbana-Champaign, 3Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 4Bioengineering, University of Illinois at Urbana-Champaign
Dielectrophoresis (DEP) is an effective method to manipulate cells. Printed circuit boards (PCB) can provide inexpensive, reusable and effective electrodes for contact-free cell manipulation within microfluidic devices. By combining PDMS-based microfluidic channels with coverslips on PCBs, we demonstrate bead and cell manipulation and separation within multichannel microfluidic devices.
JoVE General
Denaturing Urea Polyacrylamide Gel Electrophoresis (Urea PAGE)
1School of Biological Sciences, Nanyang Technological University, Singapore - NTU, 2Singapore-MIT Alliance for Reserach and Technology (SMART)
Denaturing urea polyacrylamide gel electrophoresis is used to separate single-stranded DNA or RNA up to a limit of 500 nucleotides. Urea in combination with heat denatures samples and unstructured single strands migrate within the gel matrix according to their molecular weight.
JoVE Neuroscience
Imaging Analysis of Neuron to Glia Interaction in Microfluidic Culture Platform (MCP)-based Neuronal Axon and Glia Co-culture System
1Department of Neuroscience, Tufts University, 2Neuroscience Program, Tufts Sackler School of Graduate Biomedical Sciences
This study describes the procedures of setting up a novel neuronal axon and (astro)glia co-culture platform. In this co-culture system, manipulation of direct interaction between a single axon (and single glial cell) becomes feasible, allowing mechanistic analysis of the mutual neuron to glial signaling.
JoVE Neuroscience
Microdialysis of Ethanol During Operant Ethanol Self-administration and Ethanol Determination by Gas Chromatography
College of Pharmacy, Division of Pharmacology and Toxicology, The University of Texas at Austin
A method to determine the time course of ethanol concentration in the brains of rats during operant ethanol self-administration is described. Gas chromatography with flame ionization detection is used to quantify ethanol in the dialysate samples, because it has the sensitivity required for the small volumes that are generated.
JoVE General
Studying Proteolysis of Cyclin B at the Single Cell Level in Whole Cell Populations
Department of Hematology, Oncology and Stem Cell Transplantation, University Medical Center Freiburg
Metaphase to anaphase transition is triggered through anaphase-promoting complex (APC/C)-dependent ubiquitination and subsequent destruction of cyclin B. Here, we established a system which, following pulse-chase labeling, allows monitoring cyclin B proteolysis in entire cell populations and facilitates the detection of interference by the mitotic checkpoint.
JoVE Clinical and Translational Medicine
Catheter Ablation in Combination With Left Atrial Appendage Closure for Atrial Fibrillation
Department of Cardiology, St. Antonius Hospital, The Netherlands
Catheter ablation is combined with placement of the WATCHMAN Left Atrial Appendage Closure Device to prevent ischemic stroke in a patient with non-valvular atrial fibrillation.
JoVE Neuroscience
A Galvanotaxis Assay for Analysis of Neural Precursor Cell Migration Kinetics in an Externally Applied Direct Current Electric Field
1Institute for Biomaterials and Biomedical Engineering, University of Toronto, 2Lyndhurst Centre, Toronto Rehabilitation Institute, 3Department of Surgery, University of Toronto
In this protocol we demonstrate how to construct custom chambers that permit the application of a direct current electric field to enable time-lapse imaging of adult brain derived neural precursor cell translocation during galvanotaxis.
JoVE Neuroscience
Single-unit In vivo Recordings from the Optic Chiasm of Rat
Department of Biomedical Engineering, Boston University
Retinal ganglion cells transmit visual information from the eye to the brain with sequences of action potentials. Here, we demonstrate how to record the action potentials of single ganglion cells in vivo from anesthetized rats.
JoVE Bioengineering
Time-lapse Fluorescence Imaging of Arabidopsis Root Growth with Rapid Manipulation of The Root Environment Using The RootChip
1Department of Plant Biology, Carnegie Institution for Science, 2Howard Hughes Medical Institute, 3Departments of Applied Physics and Bioengineering, Stanford University, 4Department of Microsystems Engineering (IMTEK) and Center for Biological Signaling Studies (BIOSS), University of Freiburg
This article provides a protocol for cultivation of Arabidopsis seedlings in the RootChip, a microfluidic imaging platform that combines automated control of growth conditions with microscopic root monitoring and FRET-based measurement of intracellular metabolite levels.
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 Neuroscience
A Lightweight, Headphones-based System for Manipulating Auditory Feedback in Songbirds
1Department of Biology, Emory University, 2Neuroscience Graduate Program, Emory University, 3Program in Neuroscience and Behavioral Biology, Emory University
We describe the design and assembly of miniaturized headphones suitable for replacing a songbird’s natural auditory feedback with a manipulated acoustic signal. Online sound processing hardware is used to manipulate song output, introduce real-time errors in auditory feedback via the headphones, and drive vocal motor learning.
JoVE Bioengineering
Measurement of Aggregate Cohesion by Tissue Surface Tensiometry
Department of Surgery, UMDNJ-Robert Wood Johnson Medical School
We describe a method of measuring binding energy, expressible as tissue surface tension, between cells within 3D tissue-like aggregates. Differences in tissue surface tension have been demonstrated to correlate with invasiveness of lung, muscle, and brain tumors, and are fundamental determinants of establishing spatial relationships between different cell types.
JoVE General
Isolation and Biophysical Study of Fruit Cuticles
1Department of Chemistry, City College of New York, City University of New York Graduate Center and Institute for Macromolecular Assemblies, 2Department of Chemical Engineering, City College of New York
Aerial plant organs are protected by the cuticle, a supramolecular biopolyester-wax assembly. We present protocols to monitor selective removal of epi- and intracuticular waxes from tomato fruit cuticles on molecular and micro scales by solid-state NMR and atomic force microscopy, respectively, and to assess the cross-linking capacity of engineered cuticular biopolyesters.
JoVE Editorial
February 2013: This Month in JoVE
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
Here's a look at what's coming up in the February 2013 Issue of Journal of Visualized Experiments (JoVE).
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.
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JoVE Applied Physics
Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities
Department of Physics and Astronomy, University of Utah
The system described herein employs a traditional optical trap as well as an independent holographic optical trapping line, capable of creating and manipulating multiple traps. This allows for the creation of complex geometric arrangements of refractive particles while also permitting simultaneous high-speed, high-resolution measurements of the activity of biological enzymes.
JoVE Applied Physics
Dry Oxidation and Vacuum Annealing Treatments for Tuning the Wetting Properties of Carbon Nanotube Arrays
Graduate Aeronautical Laboratories, California Institute of Technology
This article describes a simple method to fabricate vertically aligned carbon nanotube arrays by CVD and to subsequently tune their wetting properties by exposing them to vacuum annealing or dry oxidation treatment.
JoVE General
Assembly, Loading, and Alignment of an Analytical Ultracentrifuge Sample Cell
The analytical ultracentrifuge (AUC) sample cell holds sample and reference buffer and during experiments and is exposed to high vacuum and rotor speeds up to 60,000 rpm. This video will demonstrate the rigorous attention to detail necessary for assembly, loading and alignment of this very important component of an AUC experiment.
JoVE Bioengineering
Synthesis, Assembly, and Characterization of Monolayer Protected Gold Nanoparticle Films for Protein Monolayer Electrochemistry
1Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, 2Department of Biochemistry and Molecular Biology, Gottwald Center for the Sciences, University of Richmond
Alkanethiolate stabilized gold colloids known as monolayer protected clusters (MPCs) are synthesized, characterized, and assembled into thin films as an adsorption interface for protein monolayer electrochemistry of simple redox protein like Pseudomonas aeruginosa azurin (AZ) and cytochrome c (cyt c).
JoVE Applied Physics
Fabricating Metamaterials Using the Fiber Drawing Method
Institute of Photonics and Optical Sciences (IPOS), School of Physics, University of Sydney
Metamaterials at terahertz frequencies offer unique opportunities, but are challenging to fabricate in bulk. We adapt the fabrication procedure for microstructured polymer optical fibers to inexpensively fabricate metamaterials potentially on an industrial scale. We produce polymethylmethacrylate fibers containing ~10 μm diameter indium wires separated by ~100 μm, which exhibit a terahertz plasmonic response.
JoVE Bioengineering
Bridging the Bio-Electronic Interface with Biofabrication
1Fischell Department of Bioengineering, University of Maryland, 2Institute for Bioscience and Biotechnology Research, University of Maryland, 3Department of Materials Science and Engineering, University of Maryland
This article describes a biofabrication approach: deposition of stimuli-responsive polysaccharides in the presence of biased electrodes to create biocompatible films which can be functionalized with cells or proteins. We demonstrate a bench-top strategy for the generation of the films as well as their basic uses for creating interactive biofunctionalized surfaces for lab-on-a-chip applications.
JoVE Bioengineering
Visualization of Recombinant DNA and Protein Complexes Using Atomic Force Microscopy
1College of Nursing, Interdisciplinary Life Sciences Research Laboratory, Seattle University, 2College of Science and Engineering, Interdisciplinary Life Sciences Research Laboratory, Seattle University
A tapping mode atomic force microscope (AFM) method for the visualization of plasmid DNA, cytoplasmic proteins, and DNA-protein complexes is described. The method includes alternate approaches for preparing samples for AFM imaging following biochemical manipulation. DNA containing specific protein interacting regions are observed in near-physiologic buffer conditions.
JoVE Bioengineering
Autologous Endothelial Progenitor Cell-Seeding Technology and Biocompatibility Testing For Cardiovascular Devices in Large Animal Model
1Department of Biomedical Engineering, Duke University, 2School of Medicine, Duke University, 3Department of Surgery, Duke University Medical Center, 4School of Medicine, University of Pennsylvania
A method for seeding titanium blood-contacting biomaterials with autologous cells and testing biocompatibility is described. This method uses endothelial progenitor cells and titanium tubes, seeded within minutes of surgical implantation into porcine venae cavae. This technique is adaptable to many other implantable biomedical devices.
JoVE Immunology and Infection
An In vitro Co-infection Model to Study Plasmodium falciparum-HIV-1 Interactions in Human Primary Monocyte-derived Immune Cells
Infectious Disease Research Center, CHUL (CHUQ), Quebec City, Quebec, Canada
We have developed an in vitro malaria-HIV-1 co-infection model to study the impact of Plasmodium falciparum on the HIV-1 replicative cycle in human primary monocyte-derived macrophages. This versatile system can easily be adapted to other primary cell types susceptible to HIV-1 infection.
JoVE General
A Method for 2-Photon Imaging of Blood Flow in the Neocortex through a Cranial Window
Department of Neurology, University of California, Los Angeles
Cortical blood flow dynamics can be studied in vivo by imaging fluorescent dextran dyes injected into the tail vein of rodents with 2-photon microscopy. This video shows how to image blood flow dynamics in neocortex of mice through a glass-covered cranial window preparation.
JoVE Bioengineering
Haptic/Graphic Rehabilitation: Integrating a Robot into a Virtual Environment Library and Applying it to Stroke Therapy
1Department of Bioengineering, University of Illinois at Chicago and Rehabilitation Institute of Chicago, 2Sensory Motor Performance Program, Rehabilitation Institute of Chicago
Recently, a vast amount of prospects have come available for human-robot interactive systems. In this paper we outline the integration of a new robotic device with open source software that can rapidly make possible a library of interactive functionality. We then outline a clinical application for a neurorehabilitation application.
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.
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