In a paper in the November 2007 Journal of Micromechanics and Microengineering*, the research team led by NIST engineer Michael Gaitan describes for the first time how a tiny dielectric microwave heater can be successfully integrated with a microfluidic channel to control selectively and precisely the temperature of fluid volumes ranging from a few microliters (millionth of a liter) to sub-nanoliters (less than a billionth of a liter).
Sample heating is an essential step in a wide range of analytic techniques that could be built into microfluidic devices, including the high-efficiency polymerase chain reaction (PCR) process that rapidly amplifies tiny samples of DNA for forensic work, and and methods to break cells open to release their contents for study.
The team embedded a thin-film microwave transmission line between a glass substrate and a polymer block to create its micro microwave oven. A trapezoidal-shaped cut in the polymer block only 7 micrometers across at its narrowest—the diameter of a red blood cell—and nearly 4 millimeters long (approximately the length of an ant) serves as the chamber for the fluid to be heated.
Based on classical theory of how microwave energy is absorbed by fluids, the research team developed a model to explain how their minature oven would work. They predicted that electromagnetic fields localized in the gap would directly heat the fluid in a selected portion of the micro channel while leaving the surrounding area unaffected. Measurements of the microwaves produced by the system and their effect on the fluid temperature in the micro channel validated the model by showing that the increase in temperature of the fluid was predominantly due to the absorbed microwave power.
Once the new technology is more refined, the researchers hope to use it to design a microfluidic microwave heater that can cycle temperatures rapidly and efficiently for a host of applications.
Michael E. Newman | EurekAlert!
Monocrystalline silicon thin film for cost-cutting solar cells with 10-times faster growth rate fabricated
16.03.2018 | Tokyo Institute of Technology
Research gets closer to producing revolutionary battery to power renewable energy industry
15.03.2018 | University of Kansas
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.
Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...
16.03.2018 | Event News
13.03.2018 | Event News
08.03.2018 | Event News
19.03.2018 | Trade Fair News
19.03.2018 | Life Sciences
19.03.2018 | Life Sciences