Absorbance Detection
Absorption of light correlates to the energy of a photon that is taken-up by electrons of the substance atom. The electromagnetic energy is transformed into internal energy of the absorbent substance. The absorbance of a substance quantifies how much of the incident light is absorbed by it (instead of being reflected or refracted). Precise measurements of the absorbance at many wavelengths allow the identification of a substance via absorption spectroscopy, where a sample is illuminated from one side, and the intensity of the light that exits from the sample in every direction is measured (see Fig. 1). A few examples of absorption are ultraviolet–visible (UV-Vis) spectroscopy or infrared (IR) spectroscopy.
WPI Awarded the FVMA Industry Award
World Precision Instruments was selected to receive the FVMA (Florida Veterinary Medical Association) Industry Award for 2017.
FAQ: Troubleshooting Unstable Resistance Readings from an ENDOHM
One of our frequently asked questions (FAQs) concerns TEER measurements with an EndOhm. If the resistance readings from your ENDOHM don't stabilize, you may need to do some troubleshooting.
Endohm Maintenance for Long Life
The EndOhm series of chambers, when used with WPI’s EVOM2 resistance meter or the Millicell ERS, are designed to provide reproducible and accurate resistance measurements of endothelial tissue in culture cups. Resistance values obtained with the EndOhm are consistent with those obtained using a well-designed Ussing Chamber.
Monitor the Growth of Epithelial Cells in Vitro Manually
Are you ready to perform experiments involving a cultured cell monolayer? If your monolayer has not reached confluence, you may have holes or gaps in the monolayer that would prevent collection of valid experimental data. When confluence is reached, the electrical resistance across the monolayer peaks and then plateaus. The EVOM2 meter was designed specifically for this application.
The EVOM2 is the ideal meter for use when you are making manual TEER measurements on small batches of cell cultures and do not require a high throughput system.
Choosing a Pump for your Fluid Handling Application
The type of pump you choose for your fluid handling will largely depend on your laboratory application. In this article, we will compare the popular pump types.
Application Kits for Use with the NanoFil for Microinjection
Application kits are specially designed for eye research for injecting retinal pigment epithelium (RPE) and for intraocular (IO) injections. In addition, these kits may be used for brain injection in mice. They need to be used with a NanoFil syringe and UMPIII to achieve accurate, repetitive and oil-free injection in the submicroliter range.
Surgical Instrument Care and Handling
The proper care and handling of your valuable surgical instruments will improve their longevity and function. Choose a protocol appropriate for your environment from the cleaning techniques below. See the videos here.
When a Bigger Bolus is Better
First, let's consider volumes.
- A milliliter (mL) is one thousandth the volume of a liter (L) or 10-3L
- A microliter (µL) is one thousandth the volume of a mL (10-6L)
- A nanoliter (nL) is one thousandth the volume of a µL (10-9L)
- A picoliter (pL) is one thousandth the volume of a nL (10-12L)
This is graphically represented at the right. Notice that the mL is one trillion times larger than the picoliter. The table (right) shows that the side of a cube with a volume of 1mL is 1cm long. Likewise, the side of a cube with a volume of 1pL is 10µm long. Just for comparison, it shows that the diameter of a sphere with a volume of 1mL is 1.24cm, and the volume of a sphere with a volume of 1pL is 12.4µm.
Born Before the Test Tube Baby, WPI Serves Researchers for Over 50 Years
It’s hard to imagine that surgery wasn’t always the prestigious profession it is today. But, in medieval Europe, physicians didn’t practice surgery, because such things were handled by lesser men… or even by women. Often, the local barber took care of minor surgeries. He would travel from town to town, and you could stop in to get a haircut and shave, and at the same time get a tooth pulled or have a minor surgery.
VIDEO: Using WPI's PUL-1000 Micropipette Puller
World Precision Instruments' PUL-1000 is a microprocessor controlled, four-stage, horizontal puller for making glass micropipettes or microelectrodes used in intracellular recording, microperfusion and microinjection. It offers programmable sequences of up to four steps with complete control over the heating, force, movement and cooling time. This allows graduated cycles for a variety of applications. PUL-1000 can produce pipettes with tip diameters from less than 0.1µm to 10+ µm.
FAQs about TEER Measurement
Here are some frequently asked questions (FAQ) about TEER measurement using an EVOM2.
Low Flow Dampening Kit for a Pump
A calibrated BLPR2 on the LabTrax24T was used to record the results. This is a plot of both pumps on the #14 tubing at 50 RPM into a 22 gauge needle. The flow is estimated to be 9 ml/min at 50RPM.
Recording TEER Measurements from an EVOM2
The EVOM2 is the classic, hand-held instrument for making Trans Epithelial Electrical Resistance (TEER) measurements. The REMS system adds a robot and data recording for automated TEER measurements. There may be times when you don't have a robot, but would still like to have the data recording capabilities of the REMS system. With a little ingenuity, you can do just that. Here, we will show you how you can add data recording to your standard EVOM2.
Using a DAM50 for EEG Recordings in Rodents
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.
Caring for your Surgical Instrument Investment
What's the difference between cleaning, disinfecting and sterilizing? Let's take a look. This is the first in a series of four videos to discuss some best practices in caring for your surgical instrument investment.
Calibrating Your Oxygen Sensor for use with the TBR
World Precision Instruments chemist Nikki Scafa demonstrates how to calibrate your ISO-OXY-2 or OXELP oxygen sensor with the TBR4100 free radical analyzer. For more information on biosensors, see www.wpiinc.com/biosensors.
How To Use the Micro4 Controller with a Micro Pump
Micro4™ from World Precision Instruments is an easy-to-use but very capable controller for WPI's Nanoliter Injector and UMP3 UltraMicropPump.
Nanoliter 2010, Perfect for Microinjection
WPI's Nanoliter 2010 Microinjection Pump is ideal for many applications, including zebrafish, xenopus oocytes and drosophila. MICRO4, an optional microprocessor-based controller, can provide an "intelligent" and easy-to-use interface to up to four Nanoliter Injectors. Operating parameters are set with the membrane key-pad and LCD display.
Rodent Facemask Kits for Isoflurane Anesthesia
Gas anesthesia with Isoflurane is quickly becoming the standard method of general anesthesia for rats and mice in biomedical research. The advantages of using gas anesthesia for in-vivo examinations include:
- Fewer complications than injectable agents
- Allows for longer exam duration
- Easier administration and control
- Readily incorporated into existing procedures
- Level plane of anesthesia
- Minimal animal handling/Less stress
- No controlled substances required
Zebrafish Microinjection using the UMP3/Micro4
Watch how researchers from the University of Chicago inject adult zebrafish using a 10μl NanoFil microsyringe controlled by a Micro4 controller and UltraMicroPump III (UMP3-1 includes one UMP3 pump and a Micro4 contro
Zebrafish Microinjection Technique from JoVE
Chiara Cianciolo Cosentino, at the University of Pittsburgh, describes how she uses intravenous microinjections of zebrafish larvae to study acute kidney injury in this JoVE video. You can watch this video on JoVE. WPI equipment shown in this video includes:
Buying Multi-Barrel Glass Capillaries
Two-barrel, 3-barrel, 5-barrel and 7-barrel glass capillaries are available at WPI. Multi-barrel configurations are designed especially for microiontophoresis. Because the capillaries are fused together during manufacturing, you will not need to twist them while pulling to seal the tips together. An inner filament in each barrel makes filling easy and fast.
STX100 Electrodes TEER Measurement
With the development of a High Throughput Screening (HTS) protocol for faster drug discovery, a new line of cell culture filter plates have been introduced by several major cell culture insert manufacturers. These HTS plates normally have either 24 or 96 individual cell culture inserts "bonded" together as one plate so that it can be handled by a robot apparatus. In response to these developments, WPI has developed an automatic REMS system and a manual electrode, STX100, for TEER measurements using HTS plates.