Scientists have constructed a "micro microwave," a long, narrow device measuring 4 mm long by 7 micrometers wide (the width of a red blood cell). Considered to be the smallest microwave ever, the technology will likely be used for medical "lab-on-a-chip" devices.
Micro microwave:: The gold traces on the glass circle are microwave transmission lines. The 1.25 cm wide polymer block over the transmission line in the center houses a miniature chamber in which a pinhead-sized drop of fluid is heated. (NIST)
Researchers from the National Institute of Standards of Technology (NIST) and George Mason University have recently demonstrated that the tiny microwave can heat a drop of liquid about the size of the head of a pin. The team has also integrated the microwave with a microfluidic channel to control the temperature of fluid in amounts less than a nanoliter (a billionth of a liter).
To build the device, a thin-film microwave transmission line was embedded between a glass substrate and a polymer block, as seen in the photo. The microwave chamber was cut out of the polymer block, where fluid is heated.
In operation, electromagnetic fields in the chamber heat the fluid by being absorbed by a selected portion of the micro channel, while the surrounding area that doesn't absorb microwaves is left unheated.The scientists look forward to several applications using the tiny microwave, such as heating and amplifying tiny DNA samples for forensic investigations, and breaking cells open to release their contents for analysis. The ability to precisely control the temperature of tiny volumes of fluid will also make it useful for future lab-on-a-chip devices that perform complex chemical analyses on tiny samples. In the future, the researchers hope to design a microwave heater that can cycle temperatures for further applications.
The results are published in the Journal of Micromechanics and Microengineering.
via: the National Institute of Standards and Technology