JoVE Bioengineering
In vitro Synthesis of Native, Fibrous Long Spacing and Segmental Long Spacing Collagen
1Department of Chemistry, University of Toronto, 2Institute for Optical Sciences, University of Toronto
Simple and reproducible procedures are described for making three structurally distinct collagen assemblies from a common commercially available Type I collagen monomer. Native type, fibrous long spacing or segmental long spacing collagen can be constructed by varying the conditions to which the 300 nm long and 1.4 nm diameter monomer building block is exposed.
JoVE 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 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
Live Cell Response to Mechanical Stimulation Studied by Integrated Optical and Atomic Force Microscopy
1Department of Systems Biology and Translational Medicine, College of Medicine, Cardiovascular Research Institute, Texas A&M Health Science Center, 2Department of Biomedical Engineering, Texas A&M University
This paper aims to instruct the reader in the operation of an integrated atomic force-optical imaging microscope for mechanical stimulation of live cells in culture. A step-by-step protocol is presented. A representative data set that shows live cell response to mechanical stimulation is presented.
JoVE General
Micro-Mechanical Characterization of Lung Tissue Using Atomic Force Microscopy
The stiffness of the extracellular matrix strongly influences multiple behaviors of adherent cells. Matrix stiffness varies spatially throughout a tissue, and undergoes modification in various disease conditions. Here we develop methods to characterize spatial variations in stiffness in normal and fibrotic mouse lung tissue using atomic force microscopy microindentation.
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 Applied Physics
Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells
1Center for Innovative Fuel Cells and Battery Technologies, School of Materials Science and Engineering, Georgia Institute of Technology, 2School of Chemistry and Biochemistry, Georgia Institute of Technology
We present a unique platform for characterizing electrode surfaces in solid oxide fuel cells (SOFCs) that allows simultaneous performance of multiple characterization techniques (e.g. in situ Raman spectroscopy and scanning probe microscopy alongside electrochemical measurements). Complementary information from these analyses may help to advance toward a more profound understanding of electrode reaction and degradation mechanisms, providing insights into rational design of better materials for SOFCs.
JoVE Bioengineering
Bacterial Immobilization for Imaging by Atomic Force Microscopy
1Biological and Nanoscale Systems Group, Biosciences Division, Oak Ridge National Laboratory, 2Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, 3Department of Surgery, Eastern Virginia Medical School, 4Center for Nanophase Materials Sciences Division, Oak Ridge National Laboratory
Live Gram-negative and Gram-positive bacteria can be immobilized on gelatin-coated mica and imaged in liquid using Atomic Force Microscopy (AFM).
JoVE Bioengineering
Soft Lithographic Functionalization and Patterning Oxide-free Silicon and Germanium
1Department of Chemistry, Duke University, 2Hajim School of Engineering and Applied Sciences, University of Rochester, 3Department of Chemical Engineering, University of Rochester
Here we describe a simple method for patterning oxide-free silicon and germanium with reactive organic monolayers and demonstrate functionalization of the patterned substrates with small molecules and proteins. The approach completely protects surfaces from chemical oxidation, provides precise control over feature morphology, and provides ready access to chemically discriminated patterns.
JoVE Bioengineering
Polymer Microarrays for High Throughput Discovery of Biomaterials
1Laboratory of Biophysics and Surface Analysis, University of Nottingham, 2School of Molecular Medical Sciences, University of Nottingham, 3David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology
A description of the formation of a polymer microarray using an on-chip photopolymerization technique. The high throughput surface characterization using atomic force microscopy, water contact angle measurements, X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry and a cell attachment assay is also described.
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 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 Clinical and Translational Medicine
Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain
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 Applied Physics
Characterization of Surface Modifications by White Light Interferometry: Applications in Ion Sputtering, Laser Ablation, and Tribology Experiments
1Materials Science Division, Argonne National Laboratory, 2Energy Systems Division, Argonne National Laboratory, 3MassThink LLC
White light microscope interferometry is an optical, noncontact and quick method for measuring the topography of surfaces. It is shown how the method can be applied toward mechanical wear analysis, where wear scars on tribological test samples are analyzed; and in materials science to determine ion beam sputtering or laser ablation volumes and depths.
JoVE 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 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 Clinical and Translational Medicine
Dual-mode Imaging of Cutaneous Tissue Oxygenation and Vascular Function
1Department of Biomedical Engineering, The Ohio State University, 2Department of Biomedical Informatics, The Ohio State University, 3Comprehensive Wound Center, The Ohio State University, 4Department of Surgery, The Ohio State University
A dual-mode imaging system was developed for non-contact assessment of cutaneous tissue oxygenation and vascular function.
JoVE General
Procedure for Fabricating Biofunctional Nanofibers
1Department of Chemistry, Clark Atlanta University, 2Department of Physics, Clark Atlanta University, 3Department of Chemistry and Chemical Biology, Cornell University
An efficient approach for preparing nanofibers decorated with functional groups capable of specifically interacting with proteins is described. The approach first requires the preparation of a polymer functionalized with the appropriate functional group. The functional polymer is fabricated into nanofibers by electrospinning. The effectiveness of the binding of the nanofibers with a protein is studied by confocal microscopy.
JoVE Bioengineering
Micropipette Aspiration of Substrate-attached Cells to Estimate Cell Stiffness
1Section of Respiratory, Critical Care and Sleep Medicine, Department of Medicine, University of Illinois, 2Institute for Medicine and Engineering, University of Pennsylvania
Here we describe a quick and simple method to measure cell stiffness. The general principle of this approach is to measure membrane deformation in response to well-defined negative pressure applied through a micropipette to the cell surface. This method provides a powerful tool to study biomechanical properties of substrate-attached cells.
JoVE Clinical and Translational Medicine
Probe-based Confocal Laser Endomicroscopy of the Urinary Tract: The Technique
1Department of Urology, Stanford University School of Medicine, 2Veterans Affairs Palo Alto Health Care System
Probe-based confocal laser endomicroscopy enables real-time microscopy of the human urinary tract during cystoscopy, providing dynamic, intravital imaging of pathological states such as bladder cancer with cellular resolution. Endomicroscopy may augment the diagnostic accuracy of standard white light endoscopy and provide intraoperative image guidance to improve surgical resection.
JoVE Applied Physics
Ultrahigh Density Array of Vertically Aligned Small-molecular Organic Nanowires on Arbitrary Substrates
Electrical and Computer Engineering, University of Alberta
We report a simple method for fabricating an ultrahigh density array of vertically ordered small-molecular organic nanowires. This method allows for synthesis of complex heterostructured hybrid nanowire geometries, which can be inexpensively grown on arbitrary substrates. These structures have potential applications in organic electronics, optoelectronics, chemical sensing, photovoltaics and spintronics.
JoVE Applied Physics
Terahertz Microfluidic Sensing Using a Parallel-plate Waveguide Sensor
Department of Electrical and Computer Engineering, Rice University
The procedure for implementing a refractive index sensor for terahertz frequencies based on a grooved parallel-plate waveguide geometry is described here. The method yields a measurement of the refractive index of a small volume of liquid through monitoring of the shift in the resonant frequency of the waveguide structure
JoVE Clinical and Translational Medicine
Corneal Confocal Microscopy: A Novel Non-invasive Technique to Quantify Small Fibre Pathology in Peripheral Neuropathies
Division of Cardiovascular Medicine, University of Manchester
Corneal Confocal microscopy is a non-invasive clinical technique which may be used to quantify C fibre damage to diagnose and stratify patients with increasing neuropathic severity.
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 Clinical and Translational Medicine
Evaluation of Cancer Stem Cell Migration Using Compartmentalizing Microfluidic Devices and Live Cell Imaging
1Department of Biomedical Engineering, University of Wisconsin-Madison, 2Materials Science Program, University of Wisconsin-Madison, 3Department of Neurological Surgery, University of Wisconsin-Madison, 4Carbone Comprehensive Cancer Center and Center for Stem Cell and Regenerative Medicine, University of Wisconsin-Madison
A compartmentalizing microfluidic device for investigating cancer stem cell migration is described. This novel platform creates a viable cellular microenvironment and enables microscopic visualization of live cell locomotion. Highly motile cancer cells are isolated to study molecular mechanisms of aggressive infiltration, potentially leading to more effective future therapies.
JoVE Bioengineering
Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography
1Department of Biomedical Engineering, Northwestern University, 2Department of Physics, Harbin Institute of Technology, 3Department of Ophthalmology, University of Southern California, 4Department of Ophthalmology, Northwestern University
Photoacoustic ophthalmology (PAOM), an optical-absorption-based imaging modality, provides the complementary evaluation of the retina to the currently available ophthalmic imaging technologies. We report the using of PAOM integrated with spectral-domain optical coherence tomography (SD-OCT) for simultaneous multimodal retinal imaging in rats.
JoVE 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 Clinical and Translational Medicine
Coculture Analysis of Extracellular Protein Interactions Affecting Insulin Secretion by Pancreatic Beta Cells
1Pediatric Diabetes Research Center, University of California, San Diego, 2Janssen Research & Development, 3Department of Medicine, University of California, San Diego
Transcellular protein interactions are important determinants of pancreatic beta-cell function. Detailed here is a method—adapted from a coculture model of synaptogenesis—for investigating how specific transmembrane proteins influence insulin secretion. Transfected HEK293 cells express proteins of interest; beta cells do not need to be transfected or otherwise directly perturbed.
JoVE Clinical and Translational Medicine
Remote Magnetic Navigation for Accurate, Real-time Catheter Positioning and Ablation in Cardiac Electrophysiology Procedures
1Cardiology, Robotic Cardiac Electrophysiology and Arrhythmia Unit, La Paz University Hospital, 2Magnetecs Corp., 3Cardiology, Geffen School of Medicine at UCLA Los Angeles
This report provides a detailed description of a new remote navigation system based on magnetic driven forces, which has been recently introduced as a new robotic tool for human cardiac electrophysiology procedures.
JoVE Applied Physics
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
School of Physics & Astronomy, University of St Andrews
Use of photonic crystal slow light waveguides and cavities has been widely adopted by the photonics community in many differing applications. Therefore fabrication and characterization of these devices are of great interest. This paper outlines our fabrication technique and two optical characterization methods, namely: interferometric (waveguides) and resonant scattering (cavities).
JoVE General
Mechanical Stimulation of Chondrocyte-agarose Hydrogels
1Department of Mechanical and Materials Engineering, Queen's University, 2Department of Chemical Engineering, Queen's University
The biosynthesis of cartilaginous extracellular matrix by chondrocytes can be affected by application of mechanical stimuli. This method describes the technique of applying dynamic compressive strains to chondrocytes encapsulated in 3D constructs and the evaluation of induced changes in chondrocyte metabolism.
JoVE Behavior
How to Detect Amygdala Activity with Magnetoencephalography using Source Imaging
1Department of Psychology, University of Wisconsin-Milwaukee, 2McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, 3Department of Neurology, Medical College of Wisconsin
This article describes how to record amygdala activity with magnetoencephalography (MEG). In addition this article will describe how to conduct trace fear conditioning without awareness, a task that activates the amygdala. It will cover 3 topics: 1) Designing a trace conditioning paradigm using backward masking to manipulate awareness. 2) Recording brain activity during the task using magnetoencephalography. 3) Using source imaging to recover signal from subcortical structures.
JoVE General
Studying the Effects of Matrix Stiffness on Cellular Function using Acrylamide-based Hydrogels
Department of Pharmacology, University of Pennsylvania
The effect of substrata stiffness on cellular function can be modeled in vitro using polyacrylamide hydrogels of varying compliances.
JoVE Bioengineering
Demonstrating the Uses of the Novel Gravitational Force Spectrometer to Stretch and Measure Fibrous Proteins
Department of Biological Sciences, University of North Texas
This is a step-by step guide showing the purpose, operation, and representative results from the novel gravitational force spectrometer.
JoVE Applied Physics
Micro 3D Printing Using a Digital Projector and its Application in the Study of Soft Materials Mechanics
Department of Mechanical Engineering, Massachusetts Institute of Technology
We demonstrate controlled pattern transformation of swelling gel tubes by elastic instability. A simple projection micro stereo-lithography setup is built using an off-the-shelf digital data projector to fabricate three-dimensional polymeric structures in a layer-by-layer fashion. Swelling hydrogel tubes under mechanical constraint display various circumferential buckling modes depending on dimension.
JoVE General
Making Patch-pipettes and Sharp Electrodes with a Programmable Puller
1Department of Molecular and Cellular Physiology, Stanford University, 2Department of Molecular and Cellular Physiology, Stanford University School of Medicine
This video shows how to use a programmable puller to make patch pipettes and sharp electrodes for electrophysiology. The same procedure can be used to make a variety of glass tools, including injection needles.
JoVE Bioengineering
On-chip Isotachophoresis for Separation of Ions and Purification of Nucleic Acids
Mechanical Engineering, Stanford University
Isotachophoresis (ITP) is a robust electrokinetic separation and preconcentration technique with applications ranging from toxin detection to sample preparation. We review the physical principles of ITP and the methodology of applying this technique to two specific example applications: separation and detection of small molecules and purification of nucleic acids from cell culture lysate.
JoVE Applied Physics
Development of Whispering Gallery Mode Polymeric Micro-optical Electric Field Sensors
Mechanical Engineering Department, Southern Methodist University
A high-sensitivity photonic micro sensor was developed for electric field detection. The sensor exploits the optical modes of a dielectric sphere. Changes in the external electric field perturb the sphere morphology leading to shifts in its optical modes. The electric field strength is measured by monitoring these optical shifts.
JoVE 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
A Quantitative Assessment of The Yeast Lipidome using Electrospray Ionization Mass Spectrometry
Department of Biology, Concordia University
We describe a new quantitative lipidomics method for identifying numerous lipid species in yeast using survey-scan electrospray ionization mass spectrometry (ESI/MS). This method exceeds currently available methods for lipid identification and quantification in the ability to resolve various molecular forms of lipids, sensitivity, and speed.
JoVE General
Dissection of Saccharomyces Cerevisiae Asci
Department of Biology, Concordia University
Micromanipulation of yeast cells is needed for meiotic genetic analysis or to select diploid zygotes. These micromanipulations are carried out using the microneedle of a dissection microscope. The microneedle is used to relocate cells and is controlled by a micromanipulator which are available with various degrees of automation.
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 Applied Physics
In-situ Tapering of Chalcogenide Fiber for Mid-infrared Supercontinuum Generation
Edward L. Ginzton Laboratory, Stanford University
We describe a method for in-situ tapering of As2S3 fibers to achieve efficient mid-infrared supercontinuum generation. By tapering while monitoring the supercontinuum’s spectrum, the spectral width can be maximized for a fiber taper. In-situ fiber tapering can be applied to optimize the performance of other fiber-based devices.
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 General
Crystallizing Membrane Proteins for Structure Determination using Lipidic Mesophases
Herein is described the procedure implemented in the Caffrey Membrane Structural and Functional Biology Group to set up manually crystallization trials of membrane proteins in lipidic mesophases.
JoVE Clinical and Translational Medicine
Transthoracic Echocardiography in Mice
1Department of Molecular Physiology and Biophysics, Baylor College of Medicine (BCM), 2The Margaret M. and Albert B. Alkek Department of Medicine, Baylor College of Medicine (BCM)
Transthoracic echocardiography offers a noninvasive method for the evaluation of cardiac function in mice. A combination of ultrasound and Doppler imaging modalities can be used to obtain dimensional measurements of the heart and intracardiac blood flow, which together provide an assessment of cardiac systolic and diastolic performance.
JoVE Neuroscience
Combining Transcranial Magnetic Stimulation and fMRI to Examine the Default Mode Network
Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center
In this article, we examine the methodology and considerations relevant to the combination of TMS and fMRI to examine the effects of brain stimulation on the default network.
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 Behavior
Use of the Operant Orofacial Pain Assessment Device (OPAD) to Measure Changes in Nociceptive Behavior
1Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, 2Department of Neuroscience, McKnight Brain Institute, University of Florida College of Medicine, 3Stoelting Co., 4Department of Orthodontics, University of Florida
We present a user-friendly, high-throughput operant system for the evaluation of pain behaviors in awake, conscious rodents. The Orofacial Pain Assessment Device (OPAD) can assess pain through a reward/conflict paradigm thus providing a more humane way of testing. This protocol will yield more clinically relevant and translational data from rodents.
JoVE Bioengineering
Three-dimensional Optical-resolution Photoacoustic Microscopy
Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis
Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technology capable of imaging optical absorption contrasts in vivo with cellular resolution and sensitivity. Here, we provide a visualized instruction on the experimental protocols of OR-PAM, including system configuration, system alignment, typical in vivo experimental procedures, and functional imaging schemes.
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