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:11/21/2016)... Nov. 21, 2016   Neurotechnology , a ... technologies, today announced that the MegaMatcher On Card ... submitted for the NIST Minutiae Interoperability Exchange ... the mandatory steps of the evaluation protocol. ... continuing test of fingerprint templates used to establish ...
(Date:11/15/2016)... , Nov. 15, 2016  Synthetic Biologics, Inc. ... therapeutics focused on the gut microbiome, today announced ... 25,000,000 shares of its common stock and warrants ... at a price to the public of $1.00 ... Synthetic Biologics from the offering, excluding the proceeds, ...
(Date:6/22/2016)...  The American College of Medical Genetics and Genomics was ... as one of the fastest-growing trade shows during the Fastest ... in Las Vegas . ... in each of the following categories: net square feet of ... attendees. The 2015 ACMG Annual Meeting was ranked 23 out ...
Breaking Biology News(10 mins):
(Date:11/30/2016)... CA (PRWEB) , ... November 30, 2016 , ... ... a new moving magnet Voice Coil Actuator with a flexure design that ensures ... long life with cost-effective pricing and is ideally suited where extreme precision is ...
(Date:11/30/2016)... , Nov. 30, 2016  The Allen ... Cell Collection: the first publicly available collection of ... cells that target key cellular structures with unprecedented ... Research, these powerful tools are a crucial first ... to better understand what makes human cells healthy ...
(Date:11/30/2016)... -- Part of 5m$ Investment in Integrated Drug ... , ... today announced that it had successfully completed the expansion of ... increased the Screening Collection to over 400,000. The new compounds ... the company. This expansion, complemented by new robotics and compound ...
(Date:11/30/2016)... ... November 30, 2016 , ... On 28 November 2016, the International Union of ... nihonium (Nh), moscovium (Mc), tennessine (Ts), and oganesson (Og), respectively for element 113, 115, ... proposed by the discoverers have been approved by the IUPAC Bureau. The IUPAC Council ...
Breaking Biology Technology: