Electrophysiology

Micromanipulators play a critical role in electrophysiology, as well as in micro/nanofabrication. Each application sector requires accurate positioning yet demands of a micromanipulator rig varies based on the specific application focus. From positioning for a patch clamp setup, in vivo placement, to fabrication of PCB/MEMS boards, each area has specific requirements that must be considered when deciding which micromanipulator is right for you. WPI offers several types of electrophysiology-focused products to suit your setup, as well as a breadth of micromanipulators to choose from for your specific application focus.  

In any laboratory, having key lab supplies is almost as important as having the major equipment. Choosing a reputable supplier of these necessary supplies is as important as having quality laboratory supplies when you need them. WPI wants to be your partner in early drug discovery, and we stock a wide variety of lab supplies, many of which can ship the same business day. Having a variety of lab supplies ready to ship makes us a dependable research partner. Here are some of the popular supplies that we keep on hand to meet your needs for your upcoming experiment

For intracellular dual or differential studies, WPI's Duo773 has separate negative capacity controls and built-in active filtering that allows the precise balancing of time constants for artifact-free differential measurement. It comes complete with two probe headstages, 10¹⁵Ω and 10¹¹Ω probes to monitor signals from ion-specific micro-electrodes as well as KCl-filled electrodes. Jim shows you how to safely unpack and properly setup your new Duo773.

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A low-noise amplifier like the DAM50 is an excellent choice for EEG recording in rodents. WPI's amplifiers were engineered for the bio-medical researcher. While 20-30μV of noise is common in bio-amplifiers, WPI’s DAM series amplifiers generate 0.4μV RMS (root mean squared) at 0.1-100Hz. (That’s equal to about 2μV peak to peak.) This setup shows one way such recordings could be made. The RC1 electrode works well for rats, and the EP1 is more suitable for mouse cranial application.

For this application, you will need the following equipment:

• (1) DAM50 amplifier
• (1) MD4R micromanipulator
• (2) M3301EH electrode holders
• (2) Profile A single tungsten metal electrodes
• (1) M10 stand
• (1) 5052 steel base plate
• (1) 5470 cable
• (1) electrode (RC1 or EP1)

Rat Cranial Applications

1. The RC1 electrode comes with a 4' unterminated wire attached. That needs to be soldered to the green-white ground wire of the 5470 cable.
2. The red wire from the 5470 cable connects with the non-inverting input on the amplifier...more

Profile B Microelectrodes

These electrodes are sold in packages of 10.

An amplifier, in simplest terms, is an electronic device that magnifies an input signal. However, the way an amplifier is designed to handle noise and bandwidth limitations greatly affects the quality and sustainability of the final output signal.

Defining Terms

To knowledgeably discuss amplifiers, let’s define a few terms.

• Gain – The gain is the multiplier defining how much the amplitude of an input signal is increased. A signal with an X1 gain is not amplified. An X10 gain produces an output signal ten times greater than the input signal.
• Noise – Any unwanted signal fluctuations are called noise. While noise can also result from external sources, for the purpose of this discussion, we are primarily concerned with the noise resulting from the inner workings of the electronic device, our amplifier. This intrinsic noise is called shot (or schott) noise.
• Signal to Noise Ratio (SNR) – The ratio of the output signal to the noise of the amplifier is called the signal to noise ratio. The smaller...more

WPI offers a range of isolators and stimulators. Use the chart below to find the components that are compatible.

See Selection

WPI's silver-silver chloride half cells are new, improved sintered pellets with lower resistance and high strength. They are stable and well-balanced in the presence of current. These small and inexpensive half-cells are easy to work with as bath electrodes.

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Dri-Ref™ reference electrodes were developed by WPI to have extremely low electrolyte leakage properties, hence the name “Dri-Ref.” In addition to this key feature, these electrodes exhibit stable and reproducible potential and low resistance. Stored in KCl when not in use, they have a long life expectancy. Low leakage is achieved by using KONBO™, a product combining modern ceramic and conductive polymer technology, as the liquid junction. Electrode resistance is low, an important consideration when making low-noise measurements.

Although the internal filling solution contains KCI, the low fluid leakage means Dri-Ref may be used in combination with ion selective electrodes, including those for K⁺ and Cl^-, without significant contamination from the reference electrode.

The Dri-Ref electrodes are chemically resistant to strong acids and alkalines. Dri-Ref electrodes are not suitable for use in organic solvents. In addition, the long, thin FLEXREF may be easily manipulated to accommodate...more

Isolated Stimulation and Stimulus Isolators

The term stimulation refers to the delivery of energy of some kind to a biological tissue in order to elicit an observable response.

Although the energy used in stimulation may be chemical, thermal, mechanical or electrical, this discussion will focus on electrical stimulation. Electrical stimulation of biological tissues involves the delivery of current and voltage to the stimulation site. The two quantities are related by Ohm's law:

V=IR

Where V is the applied voltage, I is the current and R is the electrical resistance of the tissue and or the stimulating electrodes. This simple equation shows that if voltage is constant, current flow will diminish if the tissue/electrode resistance goes up, and will increase if the resistance decreases.

More commonly, the resistance of tissue differs from sample to sample, and the resistance of the electrodes changes with applied current over time in a process called polarization.

Types of Stimulus Devices...more

NOTE: A heat treated tip is ideal for penetrating tough membranes. (It is not recommended for chronic implantation.) This process is performed using a microforge in which the heating element is positioned in close proximity to the tip in order to melt the Parylene-C distal to the exposed metal. It provides a smooth transition and produces better adherence of the Parylene-C to the metal. Both the KT and non-KT electrodes are heat-treatable. The heat treatment is applied only to the parylene coating. The heat melts the parylene so it feathers down close to the shank near where the tip is exposed. This removes the abrupt edge where the parylene has been removed to create the tip exposure. The purpose is to prevent the parylene from delaminating from the electrode during implantation into tissue which could catch on the edge. Heat treatment does not work well in chronic applications, because the feather edge is susceptible to fluid intrusion overtime, which will alter the impedance characteristics...more

Profile A Metal Microelectrodes

Introductory Assortments

Each of these assortment kits includes electrodes with different impedance within each style. Use an assortment kit to determine which electrode you need for your experiment. Each box includes the electrodes listed. There are no mix and match assortment kits.

Profile A

Profile B

Profile C

Assortments Profile A Comparison Chart 

Assortments Profile B Comparison Chart 

Assortments Profile C Comparison Chart 

Concentric Electrodes*

WPI offers an array of metal microelectrodes. In this guide, we will look at introductory assortments, concentric electrodes, profile A, profile B and profile C electrodes. For basic information on these types of metal electrodes, see the Metal Microelectrode Basics page. Links to these related posts appear below this article.

Eligoy Steel is a *Cobalt/chromium/nickel alloy.

Deciphering Part Numbers

Profile B