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:4/19/2017)... April 19, 2017 The global ... landscape is marked by the presence of several large ... held by five major players - 3M Cogent, NEC ... accounted for nearly 61% of the global military biometric ... in the global military biometrics market boast global presence, ...
(Date:4/11/2017)... GARDENS, Fla. , April 11, 2017 /PRNewswire/ ... management and secure authentication solutions, today announced that ... by Intelligence Advanced Research Projects Activity (IARPA) to ... IARPA,s Thor program. "Innovation has been ... and IARPA,s Thor program will allow us to ...
(Date:4/5/2017)... Allen Institute for Cell Science today announces the launch ... dynamic digital window into the human cell. The website ... deep learning to create predictive models of cell organization, ... suite of powerful tools. The Allen Cell Explorer will ... resources created and shared by the Allen Institute for ...
Breaking Biology News(10 mins):
(Date:10/10/2017)... , ... October 10, 2017 , ... ... and business process optimization firm for the life sciences and healthcare industries, announces ... conference in San Francisco. , The presentation, “Automating GxP Validation for Agile Cloud ...
(Date:10/9/2017)... N.C. (PRWEB) , ... October 09, 2017 , ... At ... announced Dr. Christopher Stubbs, a professor in Harvard University’s Departments of Physics and Astronomy, ... Stubbs was a member of the winning team for the 2015 Breakthrough Prize in ...
(Date:10/7/2017)... ... October 06, 2017 , ... ... launched its ProxiMeta™ Hi-C metagenome deconvolution product, featuring the first commercially available ... bioinformatics software to perform Hi-C metagenome deconvolution using their own facilities, supplementing ...
(Date:10/5/2017)... ... October 05, 2017 , ... LabRoots , the ... from around the world, is giving back to cancer research with a month-long promotion ... , Now through October 31, shoppers can use promo code PinkRibbon to get 10 ...
Breaking Biology Technology: