JoVE Bioengineering
Measurement of Bioelectric Current with a Vibrating Probe
Dermatology, University of California, Davis
The manufacture, calibration and use of non-invasive vibrating probes to measure bioelectric current in various biological systems is described.
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
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
Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices
1Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, CNRS UMR 7241, INSERM U1050, Collège de France, 2Paris Diderot University
The preparation of acute brain slices from isolated hippocampi, as well as the simultaneous electrophysiological recordings of astrocytes and neurons in stratum radiatum during stimulation of schaffer collaterals is described. The pharmacological isolation of astroglial potassium and glutamate transporter currents is demonstrated.
JoVE General
Whole-Cell Recording of Calcium Release-Activated Calcium (CRAC) Currents in Human T Lymphocytes
Department of Physiology and Membrance Biology, University of California, Davis
We provide a step-by-step protocol for whole-cell patch clamp recording of Calcium Release-Activated Calcium (CRAC) currents in peripheral blood mononuclear cell-derived human T lymphocytes.
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 Clinical and Translational Medicine
Dorsal Column Steerability with Dual Parallel Leads using Dedicated Power Sources: A Computational Model
Boston Scientific , Neuromodulation
Using a mathematical model of spinal cord stimulation, we found that a multi-source system with independent power sources for each contact can target more central points of stimulation on the dorsal column (100 vs 3) and has 50-fold more field steering resolution (0.02mm vs 1mm) than a single-source system.
JoVE Neuroscience
Electrode Positioning and Montage in Transcranial Direct Current Stimulation
1Headache & Orofacial Pain Effort (H.O.P.E.), Biologic & Material Sciences, School of Dentistry, University of Michigan, 2Laboratory of Neuromodulation, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, 3Charité, University Medicine Berlin, 4Department of Biomedical Engineering, The City College of New York
Transcranial direct current stimulation (tDCS) is an established technique to modulate cortical excitability1,2. It has been used as an investigative tool in neuroscience due to its effects on cortical plasticity, easy operation, and safe profile. One area that tDCS has been showing encouraging results is pain alleviation 3-5.
JoVE Neuroscience
GABA-activated Single-channel and Tonic Currents in Rat Brain Slices
Department of Neuroscience, Uppsala University, Sweden
We use the patch-clamp technique to measure GABA-activated single-channel currents (GABAA channels, GABAA receptors) and the synaptic and tonic currents they generate in neurons. Activation of the channels decreases neuronal excitability in health and disease 1,2,3,4.
JoVE Bioengineering
Monitoring Protein Adsorption with Solid-state Nanopores
Department of Physics, Syracuse University
A method of using solid-state nanopores to monitor the non-specific adsorption of proteins onto an inorganic surface is described. The method employs the resistive-pulse principle, allowing for the adsorption to be probed in real-time and at the single-molecule level. Because the process of single protein adsorption is far from equilibrium, we propose the employment of parallel arrays of synthetic nanopores, enabling for the quantitative determination of the apparent first-order reaction rate constant of protein adsorption as well as and the Langmuir adsorption constant.
JoVE General
Exploring Arterial Smooth Muscle Kv7 Potassium Channel Function using Patch Clamp Electrophysiology and Pressure Myography
Department of Molecular Pharmacology & Therapeutics, Loyola University Chicago
Measurements of Kv7 (KCNQ) potassium channel activity in isolated arterial myocytes (using patch clamp electrophysiological techniques) in parallel with measurements of constrictor/dilator responses (using pressure myography) can reveal important information about the roles of Kv7 channels in vascular smooth muscle physiology and pharmacology.
JoVE Neuroscience
Preparation of Drosophila Central Neurons for in situ Patch Clamping
School of Life Sciences, Arizona State University
In situ patch clamp recordings are used for electrophysiological characterization of neurons in intact circuitry. In the Drosophila genetic model patch clamping is difficult because the CNS is small and surrounded by a robust sheath. This article describes the procedure to remove the sheath and clean neurons for subsequent patch clamp recordings.
JoVE General
Electrophysiological Recording in the Drosophila Embryo
1Department of Biological Sciences, University of Illinois, 2Department of Biological Sciences, Vanderbilt University
Electrophysiological recordings from Drosophila embryos allow analyses of developing muscle and neuron electrical properties, as well as characterization of functional synaptogenesis at the glutamatergic neuromuscular junction and central cholinergic and GABAergic synapses.
JoVE Neuroscience
Whole Mount Preparation of the Adult Drosophila Ventral Nerve Cord for Giant Fiber Dye Injection
Department of Biological Sciences, Florida Atlantic University
An in vivo dissection of the adult Drosophila ventral nerve cord (VNC) is demonstrated. This particular dissection method causes little damage to the VNC allowing the subsequent labeling of the giant fiber neurons with fluorescent dye for high resolution imaging.
JoVE Applied Physics
Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping
School of Photovoltaics, University of New South Wales
Polycrystalline silicon thin-film solar cells on glass are fabricated by deposition of boron and phosphorous doped silicon layers followed by crystallisation, defect passivation and metallisation. Plasmonic light-trapping is introduced by forming Ag nanoparticles on the silicon cell surface capped with a diffused reflector resulting in ~45% photocurrent enhancement.
JoVE Neuroscience
Single Cell Measurement of Dopamine Release with Simultaneous Voltage-clamp and Amperometry
1Department of Neuroscience, University of Florida, 2Department of Psychiatry, University of Florida
The amperometric technique measures dopamine release from a single cell by detecting the oxidative current produced by spontaneous dopamine oxidization. Simultaneous voltage clamp and amperometry methodology reveal the mechanistic relationship between the overall "activity" of dopamine transporter and the regulatory role of this activity on the reverse transport of dopamine.
JoVE Neuroscience
Manufacturing and Using Piggy-back Multibarrel Electrodes for In vivo Pharmacological Manipulations of Neural Responses
Department of Physiology & Biophysics, University of Colorado Medical Campus
Iontophoresis of neural agonists and antagonists during extracellular in vivo recordings is a powerful way to manipulate a neuron’s microenvironment. These manipulations can most easily be done via piggy-back multibarrel electrodes. Here we describe how to manufacture them and use them during auditory recordings.
JoVE Neuroscience
Flash Photolysis of Caged Compounds in the Cilia of Olfactory Sensory Neurons
1SISSA, International School for Advanced Studies, 2Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 3SISSA Unit, Italian Institute of Technology
Photolysis of caged compounds allows the production of rapid and localized increases in the concentration of various physiologically active compounds. Here, we show how to obtain patch-clamp recordings combined with photolysis of caged cAMP or caged Ca for the study of olfactory transduction in dissociated mouse olfactory sensory neurons.
JoVE Neuroscience
Presynaptic Dopamine Dynamics in Striatal Brain Slices with Fast-scan Cyclic Voltammetry
1Department of Chemistry, Wayne State University,
Using fast-scan cyclic voltammetry to measure electrically evoked presynaptic dopamine dynamics in striatal brain slices.
JoVE Neuroscience
Implementing Dynamic Clamp with Synaptic and Artificial Conductances in Mouse Retinal Ganglion Cells
1Discipline of Biomedical Science, School of Medical Sciences, Sydney Medical School and Bosch Institute, University of Sydney, 2The MARCS Institute, University of Western Sydney, 3Discipline of Physiology, School of Medical Sciences, Sydney Medical School and Bosch Institute, University of Sydney
This video article illustrates the set-up, the procedures to patch cell bodies and how to implement dynamic clamp recordings from ganglion cells in whole-mount mouse retinae. This technique allows the investigation of the precise contribution of excitatory and inhibitory synaptic inputs, and their relative magnitude and timing to neuronal spiking.
JoVE Neuroscience
An Isolated Semi-intact Preparation of the Mouse Vestibular Sensory Epithelium for Electrophysiology and High-resolution Two-photon Microscopy
1Discipline of Biomedical Science, School of Medical Sciences, Sydney Medical School, University of Sydney, 2School of Biomedical Sciences and Pharmacy, University of Newcastle
Analysis of vestibular hair cell function is complicated by their location deep within the hardest part of the skull, the petrous temporal bone. Most functional hair cell studies have used acutely isolated hair cells. Here we describe a semi-intact preparation of mouse vestibular epithelium for electrophysiological and two-photon microscopy studies.
JoVE Neuroscience
Local Application of Drugs to Study Nicotinic Acetylcholine Receptor Function in Mouse Brain Slices
Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University
In this paper, we describe a useful method to study ligand-gated ion channel function in neurons of acutely isolated brain slices. This method involves the use of a drug-filled micropipette for local application of drugs to neurons recorded using standard patch clamp techniques.
JoVE Neuroscience
Nerve Excitability Assessment in Chemotherapy-induced Neurotoxicity
1Prince of Wales Clinical School, University of New South Wales, 2Neuroscience Research Australia, University of New South Wales, 3School of Medical Sciences, University of New South Wales
This abstract describes a novel method to assess the development of neurotoxicity in patients receiving chemotherapy treatment. While conventional assessment methods are limited in their ability to detect early changes in nerve function, nerve excitability techniques provide early identification of patients at risk of severe neurotoxicity and insight into pathophysiology.
JoVE General
Microiontophoresis and Micromanipulation for Intravital Fluorescence Imaging of the Microcirculation
1Department of Medical Pharmacology and Physiology, University of Missouri, 2Dalton Cardiovascular Research Center, University of Missouri
Microiontophoresis entails movement of ions from a micropipette in response to a difference in electrical potential between the inside and outside of the micropipette. Biologically active molecules are thereby delivered in proportion to electrical current. We illustrate acetylcholine microiontophoresis in conjunction with micromanipulation to study endothelium-dependent vasodilation in the microcirculation.
JoVE Neuroscience
Simultaneous Intracellular Recording of a Lumbar Motoneuron and the Force Produced by its Motor Unit in the Adult Mouse In vivo
Department of Physiology, Northwestern University Feinberg School of Medicine
This new method permits the simultaneous intracellular recording of a single adult mouse motoneuron and the measurement of the force produced by its muscle fibers. The combined investigation of the electrical and mechanical properties of motor units in normal and genetically modified animals is a breakthrough for the study of the neuromuscular system.
JoVE General
Recapitulation of an Ion Channel IV Curve Using Frequency Components
Bioengineering, University of Utah
There are technical obstacles to measuring current flux through multiple ion channels simultaneously, and later discerning what portion of the transmembrane current is due to each channel type. To address this need, this method presents a way to generate the IV curve of individual channel types using specific frequency components.
JoVE Neuroscience
Vibrodissociation of Neurons from Rodent Brain Slices to Study Synaptic Transmission and Image Presynaptic Terminals
1Section on Synaptic Pharmacology/Laboratory for Integrative Neuroscience, National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism, 2Department of Electronics Engineering, Ewha Womans University, 3Section on Transmitter Signaling/Laboratory of Molecular Physiology, National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism
This report demonstrates a technique for mechanical isolation of individual viable neurons retaining attached presynaptic boutons. Vibrodissociated neurons have the advantages of rapid production, excellent pharmacological control and improved space-clamp without influence from neighboring cells. This method can be used for imaging of synaptic elements and patch-clamp recording.
JoVE General
Introduction to Solid Supported Membrane Based Electrophysiology
1Department of Biophysical Chemistry, Max Planck Institute of Biophysics, 2Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt
Here we present an electrophysiological method based on solid supported membranes with focus on its applications for the characterization of electrogenic membrane transporters.
JoVE Neuroscience
Postsynaptic Recordings at Afferent Dendrites Contacting Cochlear Inner Hair Cells: Monitoring Multivesicular Release at a Ribbon Synapse
1Department of Otolaryngology-Head and Neck Surgery., The Johns Hopkins School of Medicine, 2Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas
Whole-cell patch-clamp recordings from auditory nerve fiber dendrites at the inner hair cell ribbon synapse in the mammalian cochlea.
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 Neuroscience
Patch-clamp Capacitance Measurements and Ca2+ Imaging at Single Nerve Terminals in Retinal Slices
The Vollum Institute, Oregon Health and Science University
Here we describe a protocol for the preparation of agar-embedded retinal slices that are suitable for electrophysiology and Ca2+ imaging. This method allows one to study ribbon-type synapses in retinal microcircuits using direct patch-clamp recordings of single presynaptic nerve terminals.
JoVE Behavior
Simultaneous EEG Monitoring During Transcranial Direct Current Stimulation
1Programa de Pós-Graduação em Ciências Médica, Universidade Federal do Rio Grande do Sul, 2Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), 3Laboratory of Neuromodulation, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, 4De Montfort University
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has shown initial therapeutic effects in several neurological conditions. The main mechanism underlying these therapeutic effects is the modulation of cortical excitability. Therefore, online monitoring of cortical excitability would help guide stimulation parameters and optimize its therapeutic effects. In the present article we review the use of a novel device that combines simultaneous tDCS and EEG monitoring in real time.
JoVE Neuroscience
Mapping Inhibitory Neuronal Circuits by Laser Scanning Photostimulation
1Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, 2Department of Biomedical Engineering, School of Engineering, University of California, Irvine
This paper introduces an approach of combining laser scanning photostimulation with whole cell recordings in transgenic mice expressing GFP in limited inhibitory neuron populations. The technique allows for extensive mapping and quantitative analysis of local synaptic circuits of specific inhibitory cortical neurons.
JoVE Neuroscience
MPI CyberMotion Simulator: Implementation of a Novel Motion Simulator to Investigate Multisensory Path Integration in Three Dimensions
1Department of Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, 2Laboratoire de Physiologie de la Perception et de l'Action, Collège de France - CNRS, 3Department of Brain and Cognitive Engineering, Korea University
An efficient way to gain insight into how humans navigate themselves in three dimensions is described. The method takes advantage of a motion simulator capable of moving observers in ways unattainable by traditional simulators. Results confirm that movement in the horizontal plane is underestimated, while vertical movement is overestimated.
JoVE Neuroscience
Odorant-induced Responses Recorded from Olfactory Receptor Neurons using the Suction Pipette Technique
1Monell Chemical Senses Center, 2Department of Physiology, Development & Neuroscience, Physiological Laboratory, University of Cambridge
Olfactory receptor neurons (ORNs) convert odor signals first into a receptor current that in turn triggers action potentials that are conveyed to second order neurons in the olfactory bulb. Here we describe the suction pipette technique to record simultaneously the odorant-induced receptor current and action potentials from mouse ORNs.
JoVE General
Staining Proteins in Gels
1Keck Graduate Institute of Applied Life Sciences, UVP, LLC, 2Proteomic Center, Keck Graduate Institute of Applied Life Sciences
Following separation by electrophoretic methods, proteins in a gel can be detected by several staining methods. Staining of proteins with Coomassie Blue, Silver Staining, SYPRO Orange, SYPRO Ruby are demonstrated in this video.
JoVE General
Immunoblot Analysis
1UVP, LLC, 2Proteomic Center, Keck Graduate Institute of Applied Life Sciences
Immunoblotting (western blotting) is a rapid and sensitive assay for the detection and characterization of proteins that works by exploiting the specificity inherent in antigen-antibody recognition. This video provides protocols for protein separation, blotting proteins onto membranes, immunoprobing, and visualization using chromogenic or chemiluminescent substrates.
JoVE General
Electrophoretic Separation of Proteins
Proteomic Center, Keck Graduate Institute of Applied Life Sciences
In this video, we demonstrate a method for electrophoretic separation of proteins using poly-acrylimide gel electrophoresis (PAGE).
JoVE General
Freezing, Thawing, and Packaging Cells for Transport
Molecular Pathology Laboratory Network, Inc
Cultured mammalian cells are used extensively in cell biology studies. This video describes the basic skills required to freeze and store cells and how to recover frozen stocks.
JoVE General
Trypsinizing and Subculturing Mammalian Cells
Molecular Pathology Laboratory Network, Inc
As cells reach confluency, they must be subcultured or passaged. This video will demonstrate a procedure for subculturing both adherent and suspension cells.
JoVE General
Counting and Determining the Viability of Cultured Cells
Molecular Pathology Laboratory Network, Inc
Determining the number of cells in culture is important in standardization of culture conditions and in performing accurate quantitation experiments. In this video, we demonstrate how cells are counted using a hemacytometer.
JoVE General
Phase Contrast and Differential Interference Contrast (DIC) Microscopy
Core Optical Imaging Facility, University of Texas Health Science Center at San Antonio (UTHSCSA)
This protocol highlights the principles and practical applications of Phase and Differential Interference Contrast (DIC) Microscopy
JoVE General
Major Components of the Light Microscope
Core Optical Imaging Facility, University of Texas Health Science Center at San Antonio (UTHSCSA)
The light microscope is a basic tool for the cell biologist, who should have a thorough understanding of how it works, how it should be aligned for different applications, and how it should be maintained as required to obtain maximum image-forming capacity and resolution. The components of the microscope are described in detail here.
JoVE General
Proper Care and Cleaning of the Microscope
Core Optical Imaging Facility, University of Texas Health Science Center at San Antonio (UTHSCSA)
Keeping the microscope optics clean is important for high-quality imaging. Dust, fingerprints, excess immersion oil, or mounting medium on or in a microscope causes reduction in contrast and resolution. DIC is especially sensitive to contamination and scratches on the lens surfaces. This protocol details the procedure for keeping the microscope clean.
JoVE General
Preparation and Fractionation of Xenopus laevis Egg Extracts
Department of Cell Biology, Emory University
Crude and fractionated Xenopus egg extracts can be used to provide ingredients for reconstituting cellular processes for morphological and biochemical analysis. Egg lysis and differential centrifugation are used to prepare the crude extract which in turn in used to prepare fractionated extracts and light membrane preparations.
JoVE General
Obtaining Eggs from Xenopus laevis Females
Department of Cell Biology, Emory University
The eggs of Xenopus laevis intact, lysed, and/or fractionated are useful for a wide variety of experiments. This protocol shows how to induce egg laying, collect and dejelly the eggs, and sort the eggs to remove any damaged eggs.
JoVE General
In Vitro Nuclear Assembly Using Fractionated Xenopus Egg Extracts
Department of Cell Biology, Emory University
Nuclear membrane assembly is an essential step in the cell division cycle; this process can be replicated in the test tube by combining Xenopus sperm chromatin, cytosol, and light membrane fractions. Complete nuclei are formed, including nuclear membranes with pore complexes, and these reconstituted nuclei are capable of normal nuclear processes.
JoVE Application Notes
IonFlux: Automated Patch Clamp System with Plate Reader Simplicity - ADVERTISEMENT
The IonFlux Automated Patch Clamp System provides high throughput, cost-effective ion channel screening for a wide range of electrophysiology applications. Fast compound exchange, low cost per data point, and convenient well plate formats make the system ideal for both ligand- and voltage-gated ion channel targets. The IonFlux HT provides an industry-leading 10,000 data points per day, while the IonFlux 16 provides true automated patch clamp performance for about the cost of a manual patch clamp rig.
JoVE Neuroscience
Profiling Voltage-gated Potassium Channel mRNA Expression in Nigral Neurons using Single-cell RT-PCR Techniques
Department of Pharmacology, University of Tennessee College of Medicine
Neurons are first characterized electrophysiologically. Then the cytoplasm from the recorded neuron is aspirated and subjected to reverse transcription-PCR analysis to detect the expression of mRNAs for neurotransmitter synthesis enzymes, ion channels, and receptors.
JoVE Bioengineering
Hollow Microneedle-based Sensor for Multiplexed Transdermal Electrochemical Sensing
1Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, 2Department of Biosensors and Nanomaterials, Sandia National Laboratories
This article details the construction of a multiplexed microneedle-based sensor. The device is being developed for in situ sampling and electrochemical analysis of multiple analytes in a rapid and selective manner. We envision clinical medicine and biomedical research uses for these microneedle-based sensors.
More Results...
