The Axon Instruments® series of amplifiers provide best-in-class solutions for the entire range of patch-clamp experiments. The portfolio of amplifiers includes Axopatch™ 200B for ultra low-noise single-channel recordings, MultiClamp™ 700B for whole-cell voltage-clamp and high-speed current-clamp recordings, and Axoclamp™ 900A for two-electrode voltage-clamp and current-clamp recordings.
Axopatch 200B Amplifier | MultiClamp 700B Amplifier | Axoclamp 900A Amplifier | |
Single-channel recording |
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Whole-cell voltage-clamp |
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Whole-cell current-clamp |
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Bilayer study |
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Extracellular field-potential recording |
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Amperometry/voltammetry study |
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Nanopore study |
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Intracellular sharp-electrode recording |
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Two-electrode voltage-clamp recording |
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Current-clamp is a method used to measure the resulting membrane potential (voltage) from an injection of current. To measure the membrane potential, the MultiClamp 700B and Axoclamp 900A both monitor voltage drop initiated by current injection along an in-series resistor. Current-clamp is commonly used to inject simulated, but realistic current waveforms into a cell, and monitor membrane effect. This technique is ideal for the evaluation of important cellular events such as action potentials.
Electrophysiology is the field of research studying current or voltage changes across a cell membrane. Electrophysiology techniques are widely used across a diverse range of neuroscience and physiological applications; from understanding the behavior of single ion channels in a cell membrane, to whole-cell changes in the membrane potential of a cell, to larger scale changes in field potential within the brain slices in vitro or brain regions in vivo.
An ion channel is a group of proteins that form a pore across the lipid bilayer of a cell. Each channel is permeable to a specific ion (examples: potassium, sodium, calcium, chloride). Patch-clamp is used to evaluate current or voltage in the membrane associated with ion channel activity via direct measurement in real time using ultra-sensitive amplifiers, high-quality data acquisition systems, and powerful software to evaluate the results.
The patch-clamp technique involves a glass micropipette forming a tight gigaohm (GΩ) seal with the cell membrane. The micropipette contains a wire bathed in an electrolytic solution to conduct ions. The whole-cell technique involves rupturing a patch of membrane with mild suction to provide low-resistance electrical access, allowing control of transmembrane voltage. Alternatively, investigators can pull a patch of membrane away from the cell and evaluate currents through single channels via the inside-out or outside-out patch-clamp technique.
The Patch-clamping is a versatile electrophysiological tool for understanding ion channel behavior. Every cell expresses ion channels, but the most common cells to study with patch-clamp techniques include neurons, muscle fibers, cardiomyocytes, and oocytes overexpressing single ion channels. Learn about patch-clamp electrophysiology and ion channel basics here.
Series resistance is the sum of all resistances between the amplifier and the inside of the cell using the whole-cell recording method. Due to Ohms Law, the larger this resistance, the greater the difference between the command level and the measured values. This creates an error in actual voltage or current measurement potentially leading to inaccurate observations. To overcome this, the Molecular Devices amplifiers have built-in circuitry to improve the bandwidth of the recording by compensating the error introduced by the voltage or current drop across the series resistance.
The patch-clamp technique involves a glass micropipette forming a tight gigaohm seal with the cell membrane. The micropipette contains a wire bathed in an electrolytic solution to conduct ions. To measure single ion channels, a “patch” of membrane is pulled away from the cell after forming a gigaohm seal. If a single ion channel is within the patch, currents can be measured. The Axopatch 200B, with extremely low-noise profile, is ideal for this application, maximizing signal for the smallest conductance ion channels.
In an experiment using the voltage-clamp method, the investigator controls the membrane voltage in a cell and measures the transmembrane current required to maintain that voltage. This voltage control is called a command voltage. To maintain this command voltage level, an amplifier must inject current. The current injected will be equal and opposite the current escaping through open ion channels, allowing the amplifier to measure the amount of current passing through open membrane bound ion channels.
The whole cell patch-clamp technique involves a glass micropipette forming a tight gigaohm (GΩ) seal with the cell membrane. This micropipette contains a wire bathed in an electrolytic solution to conduct ions. A patch of membrane is subsequently ruptured by mild suction so that the glass micropipette provides a low-resistance access to the whole cell, thereby allowing the investigator to control the transmembrane voltage and allowing the investigator to evaluate the sum of all currents through membrane bound ion channels.
* Holding level, current passing, filter option, multiple signal outputs, pipette offset, fast and whole cell capacitance compensation, series compensation, pipette neutralization, bridge balance
Customer Breakthrough
NMDAR ion channels are found in neurons and are frequent targets of research efforts. In addition to potentially playing a key role in learning and memory, it is also a target for re…
Customer Breakthrough
The Zoidl lab at York University, Canada, investigates the roles of pannexin channels in the nervous system in both physiological and pathological contexts, primarily using z…
Brochure
The Axon Instruments® portfolio provides comprehensive solutions for patch-clamping that includes amplifiers, digitizer, software, and accessories.
Data Sheet
Get details about Axon Digidata 1550B Low-Noise Data Acquisition System plus HumSilencer.
Customer Breakthrough
Dr. Lauren French is working with undergraduate students at Allegheny College to find out how the amyloid beta peptide implicated in Alzheimer’s disease pathology inhibits a calcium-…
User Guide
The Axon Guide, a guide to electrophysiology and Biophysics laboratory techniques
Presentations
By the end of the tutorial, you will be ready to acquire data and understand how to tailor setup configurations to meet your needs. We will explain standard setup for configuring the…
Data Sheet
Explore this Axon Axoclamp 900A Microelectrode Amplifier datasheet. this instrument offers several modes of operation that measure signals from single cells, tissue slices and whole…
Data Sheet
Learn about MultiClamp 700B Amplifier for electrophysiology and electrochemistry which is capable of single-channel & whole-cell voltage patch clamp, and much more.
Data Sheet
Download datasheet to learn about Axon Axopatch 200B Microelectrode Amplifier which includes cooling of the active elements to achieve the lowest possible electrical noise.
Infographic
This guide provides information about the Patch-Clamp Rig. It is an important electrophysiology technique with a broad range of applications.
For the latest featured videos, webinars and tutorials on our Axon instrument solution including Axon Patch-clamp Amplifiers, Digidata 1550B Digitizer plus HumSilencer, and pCLAMP Software Suite, visit our Axon Patch-Clamp Video Gallery.
Tech Tips with Jeffrey Tang: An introduction to the Humsilencer
How to Combine Traces, Calculate Rise or Decay Time Constant, and Perform Curve Fitting Using Axon pCLAMP Software
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Update and Hardware Choices for Optogenetics Considerations for Synchronized Light Patterning
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*Source: https://scholar.google.com/
Single molecules of DNA or RNA can be detected as they are driven through an α-hemolysin channel by an applied electric field. During translocation, nucleotides within the polynucleotide must pass through the channel pore in sequential, single-file order because the limiting diameter of the pore can accommodate only one strand of DNA or RNA at a time. Here we demonstrate that this nanopore behaves as a detector that can rapidly discriminate between pyrimidine and purine segments along an RNA molecule. Nanopore detection and characterization of single molecules represent a new method for directly reading information encoded in linear polymers, and are critical first steps toward direct sequencing of individual DNA and RNA molecules.
In addition to the well described fast-inactivating component of the Na+ current [transient Na+ current (INaT)], neocortical neurons also exhibit a low-voltage-activated, slowly inactivating “persistent” Na+ current (INaP), which plays a role in determining neuronal excitability and synaptic integration. We investigated the Na+ channels responsible for INaP in layer 5 pyramidal cells using cell-attached and whole-cell recordings in neocortical slices. In simultaneous cell-attached and whole-cell somatic recordings, no persistent Na+ channel activity was detected at potentials at which whole-cell INaP operates. Detailed kinetic analysis of late Na+ channel activity in cell-attached patches at 36°C revealed that somatic Na+ channels do not demonstrate “modal gating” behavior and that the probability of single late openings is extremely low (<1.4 × 10−4 or <0.02% of maximal open probability of INaT). Ensemble averages of these currents did not reveal a sustained component whose amplitude and voltage dependence could account for INaP as seen in whole-cell recordings.
Many of the molecules involved in biological signaling processes are easily oxidized and have been monitored by electrochemical methods. Temporal response, spatial considerations, and sensitivity of the electrodes must be optimized for the specific biological application. To monitor exocytosis from single cells in culture, constant potential amperometry offers the best temporal resolution, and a low-noise picoammeter improves the detection limits. Smaller electrodes, with 1-μm diameters, provided spatial resolution sufficient to identify the locations of release sites on the surface of single cells. For the study of neurotransmitter release in vivo, larger cylindrical microelectrodes are advantageous because the secreted molecules come from multiple terminals near the electrode, and the greater amounts lead to a larger signal that emerges from the Johnson noise of the current amplifier. With this approach, dopamine release elicited by two electrical stimulus pulses at 10 Hz was detected with fast-scan cyclic voltammetry in vivo. Nafion-coated elliptical electrodes have previously been shown to be incapable of detecting such concentration changes without extensive signal averaging. In addition, we demonstrate that high-pass filtering (200 Hz) of cyclic voltammograms recorded at 300 V/s decreases the background current and digitization noise at these microelectrodes, leading to an improved signal. Also, high-pass filtering discriminated against ascorbic acid, DOPAC, and acidic pH changes, three common interferences in vivo.
Headstages
Description | Details | Part Number |
Axoclamp 900A Headstage HS-9A X0.1U | x0.1 headstage | 1-2950-0359 |
Axoclamp 900A Headstage HS-9A X1U | x1 headstage | 1-2950-0360 |
Axoclamp 900A Headstage HS-9A X10U | x10 headstage | 1-2950-0361 |
Axoclamp 900A Headstage VG-9A X10U | x10 virtual ground headstage | 1-2950-0362 |
Axoclamp 900A Headstage VG-9A X100U | x100 virtual ground headstage | 1-2950-0363 |
MultiClamp 700B Headstage CV-7B | Patch-clamp headstage | 1-CV-7B |
MultiClamp 700B Headstage CV-7B/BL | Bilayer headstage | 1-CV-7B/BL |
MultiClamp 700B Headstage CV-7B/EC | Electrochemistry headstage | 1-CV-7B/EC |
Electrode holders, adapters, and holder components
Description | Details | Part Number |
Electrode Holder for U-Type Headstages | Fits glass pipettes with outer diameter of 1.0 - 1.7 mm | 1-HL-U |
Electrode Holder Replacement Caps | Set of 2 polycarbonate caps for HL-U holders | 1-HL-CAP |
Cone Washers 1.1mm ID | Set of 10 orange cone washers for HL-U holders, fit glass with outer diameter of 1.0 - 1.1 mm | 1-HLC-11 |
Cone Washers 1.3mm ID | Set of 10 orange cone washers for HL-U holders, fit glass with outer diameter of 1.1 - 1.3 mm | 1-HLC-13 |
Cone Washers 1.5mm ID | Set of 10 orange cone washers for HL-U holders, fit glass with outer diameter of 1.3 - 1.5 mm | 1-HLC-15 |
Cone Washers 1.7mm ID | Set of 10 orange cone washers for HL-U holders, fit glass with outer diameter of 1.5 - 1.7 mm | 1-HLC-17 |
Pins 1mm for HL-U Holders | Set of 3 brass pins for HL-U holders, 1mm | 1-HLP-U |
2mm Plugs with Solder Cups | Set of 5 general purpose gold plugs, 2mm, with solder cups | 1-HLP-0 |
Silver Wire | Set of 5 Ag wires, 0.25mm diameter, 50mm long | 1-HLA-005 |
Silicone Tubing for Silver Wire | 1mm ID x 70mm Long Silicone Tubing | 1-HLT-70 |
Silver/Silver Chloride Pellet Assemblies | Set of 3 Ag/AgCl pellet assemblies | 1-HLA-003 |
Adapter For BNC Holders To U-Type Headstages | Connects BNC holders to CV and HS headstages with threaded collets (U-type) | 1-HLB-U |
Right-Angle Adapter for HL-U Electrode Holders | Fits CV and HS headstages with threaded collets (U-type) | 1-HLR-U |
Model Cells
Description | Details | Part Number |
Model Cell for Oocytes | Axoclamp/ GeneClamp model cell for oocytes. Connects to U-type HS series headstages | 1-MCO-2U |
Model Cell for TEVC / DSEVC | Axoclamp/ GeneClamp model cell for two-electrode voltage clamp/ discontinuous single-electrode voltage-clamp conditions. Connects to U-type HS series headstages | 1-CLAMP-1U |
Model Cell for Whole Cell/ Single Channels | Axopatch/ GeneClamp/ MultiClamp model cell for whole-cell / single-channel patch-clamp conditions. Connects to U-type CV series headstages | 1-PATCH-1U |
Model Cell for Bilayers | Axopatch/ GeneClamp/ MultiClamp model cell for bilayer conditions. Connects to U-type CV series headstages | 1-MCB-1U |
Cables
Description | Details | Part Number |
Cable To Connect Axoclamp 2 Headstages To Axoclamp 900A Amplifier | Allows Axoclamp 2 headstages (HS-2, VG-2) to be used on Axoclamp 900A Amplifiers | 1-2100-0934 |
Miscellaneous
Description | Details | Part Number |
SoftPanel Amplifier Control Unit | Provides physical knob and button control for computer-controlled Axoclamp 900-series and MultiClamp 700-series amplifiers. Requires a USB connection. | 1-SOFTPANEL (USB) |
Remote Buzz For Axoclamp 900A | Hand-held buzz duration control for Axoclamp 900A Amplifier (1-50ms) | 1-2950-0366 |
Silver/Silver Chloride Pellet Assemblies | Set of 3 Ag/AgCl pellet assembly and Ag wire | 1-HLA-003 |