Page 6 - Lab Supplies

Surgical Loupes help to alleviate eye strain by enlarging the image when you are working on tiny subjects or conducting precision operations. They are portable and easier to use than a surgical microscope. However, they are not created equal, and choosing the pair that's right for you is important to your satisfaction.

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Factors Involved in Choosing Loupes

Choosing the correct surgical loupes for your application involves several factors, including resolution, working distance, field of view, depth of field,  magnification, weight and interpupillary distance. These terms are defined below.

Ideally, you want the lowest magnification that is suitable for your application. As a general rule, the lower the magnification, the greater the depth of field and field of vision. Likewise, the longer the working distance, the greater the field of view. The larger your field of view, the less you need to turn your head. This reduces eye strain and fatigue. It is also important...more

The barbed tubing assortment kit contains over 250 items. All the items are pictured on a grid below. The darker lines in the image grid represent centimeters, and the smaller ones are 2.5 mm apart.

The Nanoliter injector is a micro-processor controlled injection system that uses direct piston displacement. The collet assembly (exploded view) is shown in the image below. The glass pipette fits into the white, plastic sleeve (spacer). When the collet is screwed in place securely, the black rubber washers are compressed and hold the glass firmly in place.

Nanoliter 2000

A side view of the assembled Nanoliter injector is shown below.

Nanoliter 2010 

As the plunger is depressed, it pushes into the glass to expel the liquid in the pipette. Eventually, the diameter of the plunger matches that of the glass, and the plunger cannot expel any more liquid. If the plunger continues to press on the tip of the pipette, the pipette could crack or become dislodged from the plastic sleeve (spacer) inside the collet assembly. If that happens, the Nanoliter will begin to leak.

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Use the table below to compare WPI and Bovie part numbers.

• 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

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

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

A 4-way stopcock allows for 360 degrees of rotation and has the states (shown below) for each of the four available positions. A 3-way stopcock has only three positions and has the first three states shown below.

In the first state, liquid flows between points A and B.
In the second, it flows between points A and C.
In the third, it flows between points B and C.
In the fourth state (4-way only), it flows between all three points.

While they are sold in the popular kit 14011, they are also sold separately:

• 14035-10–4-way Stopcock, Luer Lock (pkg. of 10)
• 14036-15–4-way Luer Stopcock (pkg. of 15)
• 14057-10–4-way Stockcok, Luer Lock, Blue (pkg. of 10)

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Eliminate the cost and trouble of making your own micropipettes — WPI can quickly supply your need for consistently sized pre-pulled glass micropipettes for injection of dyes or proteins into cells, oocytes and for many other biomedical laboratory applications. Tip diameters (ID) range from 0.1 to 10 micrometers. Micropipettes are available as plain shank or with luer fittings.

• Schott Duran borosilicate glass
• 0.5 micrometer and smaller ID micropipettes include an internal glass fiber for easy filling
• Tip inner diameter tolerance ±20%
• Short taper yields high strength
• Nominal length ≈ 50 mm
• OD:ID = 1.33:1
• Standard capillary outer diameters are 1.0 mm (thin-wall) or 1.14 mm
• Every pipette individually tested and inspected
• Vacuum packed

Silanized Tips (Luer Shank)

Silanization waterproofs the glass to retard water when inserting into cell. This will not let the outside fluid run down the pipette and get inside so easily.

Luer kits contain many plastic parts made of a variety of materials. A common question is how to sterilize these parts. Common sterilizing methods include:

• EtO (gas)–a chemical steriliant small enough to penetrate the microbial cells that destroying nuclear cell components
• 70/30 Alcohol
• Cidex (Activated Dialdehyde solution)
• Autoclaving (wet 121°C, 15PSI for 30 minutes)–Before autoclaving, verify that the caps are properly loosened or removed to prevent any accidental implosion. Carefully clean the items with distilled water before autoclaving, because some chemicals that are inert on plastic resins at room temperature causes deterioration at high temperatures.

Can the Luer Kits be Autoclaved?

We offer to following luer kits. This table shows the materials used in each kit and whether or not the plastic parts are autoclavable.

What Materials are Autoclavable?

This table shows a...more

WPI offers a variety of precious metals and wire. The table below compares the specifications of the various wires. The following hints are offered to help you understand the part number codes and choose the wire you need:

• Micro coaxial cables (MAXxxxx) are ideal for microelectrode fabrication and construction of similar research tools. The dual shielding eliminates electrical interference caused by radio frequencies (RF), electrostatic and microphonics (e.g., bending and vibration). Available with single or dual (twin) conductors.
• Thermocouple wire is for tem­per­a­ture mon­i­tor­ing. TCK3050 has a chromel/alumel pair, for use in inert or oxidizing atmosphere at 1500-1800 °F.
• Teflon-coated stainless steel (type 304) wire (SSTxxxx) is available in 25-ft and 50-ft lengths. The Teflon coating is 4µm thick.
• Carbon wire (C3005) is a single 30µm fiber of electrochemically activated car­bon. This fiber is especially useful in micro-elec­tro­chem­i­cal experiments.
• Carbon filament wire (...more