The device has 56 separation channels with a length of 4cm, a width of 50-150µm, and a depth of 5-18µm. The channels are packed with vertical micro-cylinders. These pillars are 1-5µm thick, and are separated by gaps of 1-0.1µm. Within one channel, all pillars have an identical shape, size, and distance. The chromatograph was implemented on a 200mm Si wafer.
First, a Si oxide layer was deposited on the wafer, on which the submicron structures of the chromatograph were patterned and etched. Next, with the Si oxide layer as hard mask, the separation channels and the pillars were etched with deep reactive ion etching (DRIE). The separation channels were then connected via wider interconnecting supply channels. A 200mm glass wafer was bonded to the Si wafer, serving as a roof to close off the open separation channels. And last, access holes were etched through the back of the Si wafer.
A comparison with commercial chromatographs with macroscopic tubes shows that the micro-chromatograph is 5 to 10 times as fast, and has a better separation capacity. Also, unlike with macro-chromatographs, the separation does not degrade with higher velocities of molecule transport. The performance of the chromatograph was tested by injecting a fluid with tracer molecules in the chromatograph and following the velocity and width of the resulting tracer band.
Liquid phase chromatography is a powerful technique to separate and identify molecules. It is used, for example, in biochemistry labs to separate proteins. The molecules, suspended in a liquid, are separated by forcing them through macroscopic columns filled with micron-sized, randomly packed spherical particles. This sub-micro chromatograph validates fluid dynamic computations that predict that injecting molecules though a submicron maze of perfectly ordered structures will considerably increase the separation speed of liquid phase chromatography.
Katrien Marent | alfa
UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire
NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
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