JoVE Bioengineering
Attaching Biological Probes to Silica Optical Biosensors Using Silane Coupling Agents
Department of Biological Engineering, University of Missouri
Biosensors interface with complex, biological environments and perform targeted detection by combining highly sensitive sensors with highly specific probes attached to the sensor via surface modification. Here, we demonstrate the surface functionalization of silica optical sensors with biotin using silane coupling agents to bridge the sensor and the biological environment.
JoVE Bioengineering
Rejection of Fluorescence Background in Resonance and Spontaneous Raman Microspectroscopy
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 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 Applied Physics
Simulation, Fabrication and Characterization of THz Metamaterial Absorbers
School of Engineering, University of Glasgow
This protocol outlines the simulation, fabrication and characterization of THz metamaterial absorbers. Such absorbers, when coupled with an appropriate sensor, have applications in THz imaging and spectroscopy.
JoVE Bioengineering
Gold Nanostar Synthesis with a Silver Seed Mediated Growth Method
1Department of Physics and Astronomy, The University of Texas at San Antonio, 2Centro de Investigaciones en Optica A. C., 3Department of Biology and Neurosciences Institute, The University of Texas at San Antonio
We synthesized star shaped gold nanostars using a silver seed mediated growth method. The diameter of the nanostars ranges from 200 to 300 nm and the number of tips vary from 7 to 10. The nanoparticles have a broad surface plasmon resonance mode centered in the near infrared.
JoVE Neuroscience
C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays
1Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, 2Lewis-Sigler Institute for Integrative Genomics, Princeton University
Here we describe methods to test C. elegans associative learning and short- and long-term associative memory. These population assays employ the worms abilities to chemotax toward volatile odorants, and form positive associations upon pairing food with the chemoattractant butanone. Increasing the number of conditioning periods induces long-term memory.
JoVE Bioengineering
Lensless Fluorescent Microscopy on a Chip
Department of Electrical Engineering, University of California, Los Angeles
A lensless on-chip fluorescent microscopy platform is demonstrated that can image fluorescent objects over an ultra-wide field-of-view of e.g., >0.6-8 cm2 with <4μm resolution using a compressive sampling based decoding algorithm. Such a compact and wide-field fluorescent on-chip imaging modality could be valuable for high-throughput cytometry, rare-cell research and microarray-analysis.
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.
JoVE General
Quantifying Agonist Activity at G Protein-coupled Receptors
1Department of Pharmacology, University of California, Irvine, 2Department of Pharmacology, University of California, 3Schmid College of Science, Chapman University
A method for estimating the affinity constant of an agonist for the active state (Kb) of a G protein-coupled receptor is described. The analysis provides absolute or relative measures of Kb depending on whether constitutive receptor activation is measurable. Our method applies to various responses downstream from receptor activation.
JoVE Applied Physics
Bringing the Visible Universe into Focus with Robo-AO
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 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
Whole Cell Recordings from Brain of Adult Drosophila
This video demonstrates the procedure for isolating whole brains from adult Drosophila in preparation for recording from single neurons using standard whole cell technology. It includes images of GFP labeled cells and neurons viewed during recording.
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 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.
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.
JoVE Neuroscience
Cerebral Blood Oxygenation Measurement Based on Oxygen-dependent Quenching of Phosphorescence
1Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 2Department of Biochemistry and Biophysics, University of Pennsylvania, 3Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, 4Departments of Neurosciences and Radiology, University of California
We present an experimental procedure for measuring the partial pressure of oxygen (pO2) in cerebral vasculature based on oxygen-dependent quenching of phosphorescence. Animal preparation and imaging procedures were outlined for both large field of view CCD-based imaging of pO2 in rats and 2-photon excitation based imaging of pO2 in mice.
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 Neuroscience
Optogenetic Activation of Zebrafish Somatosensory Neurons using ChEF-tdTomato
Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles
Optogenetic techniques have made it possible to study the contribution of specific neurons to behavior. We describe a method in larval zebrafish for activating single somatosensory neurons expressing a channelrhodopsin variant (ChEF) with a diode-pumped solid state (DPSS) laser and recording the elicited behaviors with a high-speed video camera.
JoVE Neuroscience
An Optic Nerve Crush Injury Murine Model to Study Retinal Ganglion Cell Survival
1National Eye Institute, NIH, 2Ophthalmology Department, The Second Hospital of Harbin Medical University
This protocol shows how to retrogradely label retinal ganglion cells, and how to subsequently make an optic nerve crush injury in order to analyze retinal ganglion cell survival and apoptosis. It is an experimental disease model for different types of optic neuropathy, including glaucoma.
JoVE General
Optical Scatter Microscopy Based on Two-Dimensional Gabor Filters
Department of Biomedical Engineering, Rutgers University
We demonstrate a dark-field microscopy method based on Gabor-like filtering to measure subcellular dynamics within single living cells. The technique is sensitive to alterations in the structure of organelles, such as mitochondrial fragmentation.
JoVE Neuroscience
Simultaneous Electroencephalography, Real-time Measurement of Lactate Concentration and Optogenetic Manipulation of Neuronal Activity in the Rodent Cerebral Cortex
A procedure is described for manipulating the activity of cerebral cortical pyramidal neurons optogenetically while the electroencephalogram, electromyogram, and cerebral lactate concentration are monitored. Experimental recordings are performed on cable-tethered mice while they undergo spontaneous sleep/wake cycles. Optogenetic equipment is assembled in our laboratory; recording equipment is commercially available.
JoVE Neuroscience
An Experimental Platform to Study the Closed-loop Performance of Brain-machine Interfaces
Department of Bioengineering, Imperial College London
We use a closed-loop fly-machine interface to investigate general principles in neuronal control.
JoVE General
A Reversible, Non-invasive Method for Airway Resistance Measurements and Bronchoalveolar Lavage Fluid Sampling in Mice
1Department of Medicine, Baylor College of Medicine (BCM), 2Millenium Premier Group, 3Department of Immunology, Baylor College of Medicine (BCM)
Repeated measurements of rodent respiratory physiology and sampling of airway inflammatory cells are desirable, but generally not feasible. Here we describe a repeatable method for orally intubating mice that permits repeated measurements of airway hyperreactivity and sampling of airway inflammatory cells.
JoVE Applied Physics
Fabrication of Silica Ultra High Quality Factor Microresonators
1Department of Chemical Engineering and Materials Science, University of Southern California, 2Department of Electrical Engineering-Electrophysics, University of Southern California
We describe the use of a carbon dioxide laser reflow technique to fabricate silica resonant cavities, including free-standing microspheres and on-chip microtoroids. The reflow method removes surface imperfections, allowing long photon lifetimes within both devices. The resulting devices have ultra high quality factors, enabling applications ranging from telecommunications to biodetection.
JoVE General
Visualization of UV-induced Replication Intermediates in E. coli using Two-dimensional Agarose-gel Analysis
Department of Biology, Portland State University
We present a procedure by which two-dimensional agarose-gel analysis can be used to identify the structure of replication intermediates that occur following UV irradiation.
JoVE Bioengineering
Quantitative FRET (Förster Resonance Energy Transfer) Analysis for SENP1 Protease Kinetics Determination
Department of Bioengineering, Bourns College of Engineering, University of California, Riverside
A novel method involving quantitative analysis of FRET (Förster Resonance Energy Transfer) signals is described for studying enzyme kinetics. KM and kcat were obtained for the hydrolysis of the catalytic domain of SENP1 (SUMO/Sentrin specific protease 1) to pre-SUMO1 (Small Ubiquitin-like MOdifier). The general principles of this quantitative-FRET-based protease kinetic study can be applied to other proteases.
JoVE Neuroscience
Methods for Experimental Manipulations after Optic Nerve Transection in the Mammalian CNS
Department of Surgery, University of Toronto
Optic Nerve transection is a widely used model of adult CNS injury. This model is ideal for performing a number of experimental manipulations that target the retina globally or directly target the injured neuronal population of retinal ganglion cells.
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 Neuroscience
Local and Global Methods of Assessing Thermal Nociception in Drosophila Larvae
1Department of Biochemistry and Molecular Biology, The University of Texas MD Anderson Cancer Center, 2Scholars Academy/MARC Scholar, University of Houston-Downtown, 3Genes and Development Graduate Program, University of Texas Graduate School of Biomedical Sciences, 4Neuroscience Graduate Program, University of Texas Graduate School of Biomedical Sciences
In this article, we demonstrate assays to study thermal nociception in Drosophila larvae. One assay involves spatially-restricted (local) stimulation of thermal nociceptors1,2 while the second involves a wholesale (global) activation of most or all such neurons3. Together, these techniques allow visualization and quantification of the behavioral functions of Drosophila nociceptive sensory neurons.
JoVE Applied Physics
Hyperpolarized Xenon for NMR and MRI Applications
ERC Project BiosensorImaging, Leibniz-Institut für Molekulare Pharmakologie
The production of hyperpolarized xenon by means of spin exchange optical pumping (SEOP) is described. This method yields a ~10000-fold enhancement of the nuclear spin polarization of Xe-129 and has applications in nuclear magnetic resonance spectroscopy and imaging. Examples of gas phase and solution state experiments are given.
JoVE Clinical and Translational Medicine
A Simple Method of Mouse Lung Intubation
1Department of Environmental Health Sciences, Program in Respiratory Biology and Lung Disease, Johns Hopkins Bloomberg School of Public Health, 2Department of Pediatrics, Oregon Health Sciences University
This paper describes a striaghforward and efficient method of intubating mice for pulmonary function measurements or pulmonary instillation, that allows the mice to recover and be studied at later times. The procedure involves an inexpensive fiberoptic light source that directly illuminates the trachea.
JoVE Neuroscience
In vivo Neuronal Calcium Imaging in C. elegans
1Department of Physiology and Biophysics, Boston University School of Medicine, 2Boston University Photonics Center
With its small transparent body, well-documented neuroanatomy and a host of amenable genetic techniques and reagents, C. elegans makes an ideal model organism for in vivo neuronal imaging using relatively simple, low-cost techniques. Here we describe single neuron imaging within intact adult animals using genetically encoded fluorescent calcium indicators.
JoVE Neuroscience
Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System
Department of Surgery, University of Toronto
Optic Nerve transection is a widely used model of adult CNS injury. Ninety percent of retinal ganglion cells (RGCs) whose axons are completely transected (axotomy) die within 14 days after axotomy. This model is easily amenable to experimental manipulations and highly reproducible.
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 Neuroscience
Thinned-skull Cortical Window Technique for In Vivo Optical Coherence Tomography Imaging
1Division of Biomedical Sciences, University of California, Riverside, 2Department of Bioengineering, University of California, Riverside
We present a method of creating a thinned-skull cortical window (TSCW) in a mouse model for in vivo OCT imaging of the cerebral cortex.
JoVE 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 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 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 Immunology and Infection
Detection of Neu1 Sialidase Activity in Regulating TOLL-like Receptor Activation
Department of Microbiology and Immunology, Queen's University - Kingston, Ontario
The sialidase assay is a simple technical approach that will elucidate novel molecular mechanism(s) of TLR sensors of microbial infections and involvement in inflammatory diseases at the receptor level on the cell surface of live macrophages.
JoVE General
Fabrication and Operation of an Oxygen Insert for Adherent Cellular Cultures
Bioengineering, University of Illinois
Fabrication and validation of an add-on platform that offers enhanced control over the spatial and temporal oxygenation in a 6-well plate. The device is adaptable to a number of culture systems and can be used to investigate the effects of oxygen on wound healing.
JoVE General
The Preparation of Drosophila Embryos for Live-Imaging Using the Hanging Drop Protocol
Department of Biology, University of Waterloo
A simple, inexpensive, and effective method of preparing Drosophila embryos for live-imaging analysis is presented. Our protocol provides humidity and gas exchange and does not compress the Drosophila embryo. This method is suitable for GFP-based live imaging of Drosophila embryos using a stereomicroscope or upright compound microscope.
JoVE Neuroscience
How to Build a Laser Speckle Contrast Imaging (LSCI) System to Monitor Blood Flow
Biomedical Engineering Department, University of Texas at Austin
This video demonstrates how to build a Laser Speckle Contrast Imaging (LSCI) system that can easily be used to monitor blood flow.
JoVE Neuroscience
Paired Patch Clamp Recordings from Motor-neuron and Target Skeletal Muscle in Zebrafish
Vollum Institute, Oregon Health and Sciences University
Larval zebrafish represent the first vertebrate model system to allow simultaneous patch clamp recording from a spinal motor-neuron and target skeletal muscle. This video demonstrates the microscopic methods used to identify a segmental CaP motor-neuron and target muscle cells as well as the methodologies for recording from each cell type.
JoVE Clinical and Translational Medicine
Epidural Intracranial Pressure Measurement in Rats Using a Fiber-optic Pressure Transducer
Biomedical Sciences and Pharmacy, The University of Newcastle
A novel technique to record the pressures within the skull is described. The minimally invasive method uses a fibre-optic pressure sensing system to accurately measure intracranial pressure (ICP) in anaesthetized rats without causing significant brain trauma. The technique may be used in a wide range of experimental models.
JoVE Neuroscience
C. elegans Tracking and Behavioral Measurement
1Donnelly Centre, University of Toronto, 2Department of Physics and Astronomy, Vrije Universiteit, 3Okinawa Institute of Science and Technology, 4Department of Physics, University of Toronto
We have developed a video-rate tracking microscope system that can record and quantify C. elegans behavior at high resolution and high speeds. We have also developed computational methods to reduce the dimensionality of the worm images to a fundamental set of measurements that completely describe the shape of the worm.
JoVE Bioengineering
Nanotopology of Cell Adhesion upon Variable-Angle Total Internal Reflection Fluorescence Microscopy (VA-TIRFM)
Hochschule Aalen, Institut für Angewandte Forschung
Topology of cell adhesion on a substrate is measured with nanometre precision by variable-angle total internal reflection fluorescence microscopy (VA-TIRFM).
JoVE Neuroscience
Neonatal Subventricular Zone Electroporation
Department of Neurosurgery and Cellular & Molecular Physiology, Yale University School of Medicine
We demonstrate a minimally invasive technique referred to as neonatal subventricular zone electroporation. The technique consists of injecting plasmid DNA into the lateral ventricles of neonatal pups and applying electrical current to deliver and genetically manipulate neural stem cells
JoVE General
Using the Horseshoe Crab, Limulus Polyphemus, in Vision Research
Department of Biomedical Engineering, Boston University
In this video we perform electroretinogram recording, optic nerve recording, and intraretinal recording with the American horseshoe crab, Limulus Polyphemus. These electrophysiological paradigms can be used for investigating the neural basis of vision in a research or teaching lab.
JoVE Clinical and Translational Medicine
Probing the Brain in Autism Using fMRI and Diffusion Tensor Imaging
Department of Psychology, University of Alabama at Birmingham
Neuroimaging techniques, such as functional MRI and Diffusion Tensor Imaging have become increasingly useful in characterizing the cognitive and neural deficits in autism. An examination of brain connectivity in autism at a network level along with adaptations for scanning children with developmental disabilities is presented.
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).
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