Page 19 - Product Information

• Flexible Teflon microprobes are used for implantation in tissue, in spectrophotometer cuvettes, rectally in neonatal mice, in water baths, PCR thermal cyclers, etc.
• Animal rectal temperatures during surgical procedures and pyrogen testing.
• Skin temperature measurement during exercise physiology studies.

When precise temperature measurements are required, WPI can provide you with a very accurate monitor and thermocouple microprobes. WPI monitors have both resolution and accuracy of 0.1°C in the 0-50°C range and are traceable to NIST standards, whereas, other competitive electronic thermometers have an accuracy that is usually to 0.5°C or worse. Furthermore, all our type T clinical probes are guaranteed accurate to 0.1°C, due to our stringent wire standards. These are five times more accurate than competitive probes made with regular “Special Limits” wire.

Probe Sterilization Methods:

The needle microprobes and animal rectal probes are all designed to withstand sterilization by ETO gas...more

You can use the PZMIV stereo microscope with a stereotaxic frame as shown in the image below. This setup shows a PZMIV-BS. The U-frame Base Plate (502045) is shown, but most stereotaxic frames can be used in this way. Choose a stereo microscope objective that allows you plenty of room to work. For example, the 0.5X objective has 187mm working distance, or the 0.32X objective has 296mm working distance. You could also add a Z-LITE-Z186 illuminator. If necessary, use a 5 to 10 lb.counter weight on the boom stand base to prevent the microscope from tipping.

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

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EVOM was the first instrument designed to perform routine Trans Epithelial Electrical Resistance (TEER) measurement in tissue culture research. EVOM2 is the next generation, redesigned for greater usability.

The EVOM2 sports the following features:

Types

It is common for a researcher to attach a camera to a microscope. Three types of cameras are available, and two are suitable for microscopy work:

• Television (Direct video)
  • 4:3 old style video, NTSC, PAL, 480i
  • 16:9 HDTV (DVI 1.0 compliant), 720P
• Computer capture
  • USB connection
  • Firewire connection
• Commercial cameras
  • Fixed lens cameras
  • SLR cameras

First, determine what you want to do:

• Capture images
• View live video

The cameras that do both are more expensive. Lower cost options capable of live view and image capture usually are capable of capturing fewer frames per second.

Television Style Cameras

Television style cameras send live video images to a television set. They can use the old 4:3 (boxy) format or the new 16:9 cinematic format. These cameras do not come with software, nor do they connect to a computer without adding a special interface to the computer. This image can be recorded by DVRs or by adding a video input and capture card to your computer. These cameras can record video...more

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

Download a PDF version of the Biosensor Specifications Sheet here.

WPI offers a range of biosensors for monitoring nitric oxide, hydrogen peroxide, oxygen and hydrogen sulfide. Specifications for these sensors are detailed below.

• The macrosensors are 2mm "wet" sensors. These sensors are installed in a metal "sleeve" that looks like a tiny soda straw.The sleeve has a gas permeable membrane at the tip, and it is filled with an electrolyte. When it is immersed in a solution, the gas in solution (for example, nitric oxide) diffuses through the membrane, and the sensor measures it.
• The microsensors are "dry" sensors. Most microsensors monitor nitric oxide, and there is also a hydrogen peroxide microsensor available.

Macrosensors (2mm)

WPI's 2mm macrosensors are uniquely designed with an internal reference electrode. These sensors are designed for use with the TBR1025, or TBR4100. The ISO-OXY-2 and the OXELP sensors have the same specifications. However, they have different connectors...more

When it comes to setting up microinjection systems, the options appear endless. The pictures below give some broad suggestions on how you might set up your own system. Keep in mind that many parts are interchangeable depending on your needs or preferences.

In general, you will need a stereo microscope on a stand, a light source, one or two micromanipulators with stands, and one or two injection systems. The following images show various setups for microinjection, and all the WPI part numbers are included for easy reference.

Remember, when you set up your own system, choose the parts that fit your needs. For example:

• M10 or the M9 magnetic base could be used.
• PZMIV stereo microscope could be used instead of the PZMIII stereomicroscope.
• M3301 or the KITE micromanipulators can be used, and these micromanipulators can be placed on either side. (Keep in mind, though, if you wanted to use a KITE micromanipulator on the right side of the setup below, you would order a KITE-R (right hand), or...more

These instructions describe how to properly focus a binocular microscope.

1. Turn on the lamp and adjust its intensity.
2. Adjust the interpupilary distance so that the two circles of light merge into one.
3. Place a sample on the stage.
4. Select the 10X objective and look through the right eyepiece only.
5. Use the coarse and fine focus control knobs to adjust the focus of the sample.
6. When the sample is clearly visible, use only your left eye. Do NOT adjust the focus knobs. Instead, adjust the diopter on the left eyepiece until the sample comes clearly into view. The image should be clear with both eyes open.
7. Choose the desired objective. You may need to adjust the fine focus a little.

Camera/Microscope Configuration Chart

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NOTE: For an introduction to microscopes, see Microscope Basics.

A variety of microscope objectives are available. All objectives use lenses to focus light. Light is broken down into various wavelengths (colors) as it travels through a lens. The various wavelengths have different focal points. That means that red, green and blue appears to focus at different points. This is called chromatic aberration. Spherical aberrations are focal mismatches caused by the shape of the lens. Quality lenses are designed correct for chromatic and spherical aberration to bring the primary colors to a common focal point. These terms may help you determine the best objective for your application:

Achromatic objectives–This objective brings red and blue light to a common focus, and is corrected for spherical aberrations for green. It is excellent for black and white viewing. If an objective is not labeled, it is achromatic.

Fluorite or semi-apochromat objectives–These lenses are chromatically corrected...more

Microscopes are a standard laboratory tool, but purchasing the right microscope for a particular application can be a challenge. First, consider how you will use the instrument. Are you looking at slides, dissecting a small animal or performing a surgery? (The application dictates the necessary working distance and power of magnification.) What kind of a stand will you be using? (Boom stand, articulating arm or post stand) Will the microscope be used in a classroom setting? (A trinocular scope offers the option of including a camera.) Will you need a camera? (A camera allows you to project the microscope image on a PC or TV or to take still images.) The answers to these questions help you determine the required working distance, level of magnification, type of mounting stand and hardware required.

Parts of a Microscope

Eyepiece–Two or more lenses are contained in the eyepiece, and a variety of eyepieces can be used in a microscope. Typical eyepiece magnification ranges are 10X, 15X...more

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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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