Navigation Links
NIST calculations may improve temperature measures for microfluidics
Date:9/9/2009

If you wanted to know if your child had a fever or be certain that the roast in the oven was thoroughly cooked, you would, of course, use a thermometer that you trusted to give accurate readings at any temperature within its range. However, it isn't that simple for researchers who need to measure temperatures in microfluidic systemstiny, channel-lined devices used in medical diagnostics, DNA forensics and "lab-on-a-chip" chemical analyzersas their current "thermometer" can only be precisely calibrated for one reference temperature. Now, researchers at the National Institute of Standards and Technology (NIST) have proposed a mathematical solution that enables researchers to calibrate the "thermometer" for microfluidic systems so that all temperatures are covered.

Reactions taking place in microfluidic systems often require heating, meaning that users must accurately monitor temperature changes in fluid volumes ranging from a few microliters (a droplet approximately 1 millimeter in diameter) to sub-nanoliters (a droplet approximately 1/10 of millimeter in diameter). A common DNA analysis technique, for example, depends heavily on precise temperature cycling. Ordinary thermometers or other temperature probes are useless at such tiny dimensions, so some groups have turned to temperature-sensitive fluorescent dyes, particularly rhodamine B. The intensity of the dye's fluorescence decreases with increasing temperature. The idea is that the dye can be used as a noninvasive way to map the range of temperatures occurring within a microfluidic system during heating and, in turn, provide a means of calibrating that system for experiments.

However, the technique currently requires the user to base all readings on the fluorescence at a single reference temperature. Previous groups have developed "calibration curves" that relate temperature to rhodmaine B fluorescent intensity based on a reference temperature of about 23 degrees Celsius (a technique first proposed by NIST researchers David Ross, Michael Gaitan and Laurie Locascio in 2001*). But it turns out that the curves are only good for that one temperature. In an upcoming paper in Analytical Chemistry**, the NIST teamJayna J. Shah, Michael Gaitan and Jon Geistreports that changing the reference point, such as the higher temperature when a microfluidic system is first heated, introduces errors when a dye intensity-to-temperature calculation is done using current methods.

"Our analysis shows that a simple linear correction for a 40 degrees Celsius reference temperature identified errors between minus 3 to 8 degrees Celsius for three previously published sets of calibration equations derived at approximately 23 degrees Celsius," says lead researcher Shah.

To address the problem, the NIST team developed mathematical methods to correct for the shift experienced when the reference temperature changes. This allowed the researchers to create generalized calibration equations that can be applied to any reference temperature.

Microfluidic DNA amplification (production of numerous copies of DNA from a tiny sample) by the polymerase chain reaction (PCR) is one procedure that could benefit from the new NIST calculations, Shah says. "PCR requires a microfluidic device to be cycled through temperatures at three different zones starting around 65 degrees Celsius, so a useful dye intensity-to-temperature ratio would have to be based on that temperature and not a reference point of 23 degrees Celsius," she explains.


'/>"/>

Contact: Michael E. Newman
michael.newman@nist.gov
301-975-3025
National Institute of Standards and Technology (NIST)
Source:Eurekalert

Related biology news :

1. New Iowa State supercomputer, Cystorm, unleashes 28.16 trillion calculations per second
2. Shortcuts of the mind lead to miscalculations of weight and caloric intake, says Penn study
3. Carnegie Mellon urges industry to broaden carbon footprint calculations
4. Icy calculations on a hot topic
5. A breath of fresh air could improve drug toxicity screening
6. U-Iowa improves delivery of cancer-fighting molecules
7. Novel polymer could improve protein-based drugs
8. Water quality improves after lawn fertilizer ban, study shows
9. Improved air quality during Beijing Olympics could inform pollution-curbing policies
10. Technology improves salmon passage at hydropower dams
11. Short stressful events may improve working memory
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/5/2017)... 2017 Today HYPR Corp. , leading ... component of the HYPR platform is officially FIDO® ... security architecture that empowers biometric authentication across Fortune 500 ... secured over 15 million users across the financial services ... home product suites and physical access represent a growing ...
(Date:3/30/2017)... The research team of The Hong Kong ... identification by adopting ground breaking 3D fingerprint minutiae recovery and matching ... and accuracy for use in identification, crime investigation, immigration control, security ... ... A research team led by ...
(Date:3/24/2017)... The Controller General of Immigration from Maldives Mr. Mohamed Anwar ... prestigious international IAIR Award for the most innovative high security ePassport and ... ... Maldives Immigration Controller General, Mr. Mohamed ... the right) have received the IAIR award for the "Most innovative high ...
Breaking Biology News(10 mins):
(Date:6/19/2017)... ... June 19, 2017 , ... A colony of healthy ... cells and tissues by delivering pollen and nectar containing nutrients necessary for growth and ... stay healthy. , Many recent indicators point to a decline in honey bee health. ...
(Date:6/16/2017)... Rocky Hill, CT (PRWEB) , ... June 16, 2017 , ... ... of last night’s Entrepreneur Innovation Awards (EIA), held at The LOFT at Chelsea Piers ... their innovative project ideas to a panel of judges for an opportunity to secure ...
(Date:6/15/2017)... ... June 15, 2017 , ... ... (EKG) follows an artist’s journey through creative experimentation and interdisciplinary collaboration. Feature Creep, ... through July 22nd. An opening reception will be held at EKG, located at ...
(Date:6/15/2017)... ... June 15, 2017 , ... Adam Equipment, ... how to assemble a lab workstation. The guide outlines the procedure in four ... or Eclipse balance, AVT anti-vibration table, OIML/ASTM certified weights, and Adam DU specialized ...
Breaking Biology Technology: