What molecule or particle passes the finishline first? A good way to split a fluid sample into its separate parts is: organize a contest in a micro-channel. The largest parts will pass the optical detector first, the smaller ones follow at short distance. This principle of ‘hydrodynamic chromatography’ is now also possible on a chip. ‘On-chip’ separation is faster, needs tiny samples and uses minimum of harmful solvents. Marko Blom developed this separation chip within the MESA+ research institute of the University of Twente. He presents his PhD-work on December 13, 2002.
The separation channel Blom has developed is not deeper than one micron, it is one millimeter in width and some six to eight centimeters long. It has been fabricated in silicon or silicate glass. Thanks to this compact geometry, the separation is fast: bigger molecules move faster, smaller ones follow. A light-sensitive cell detects the fastest ones first. Colour characteristics provide additional information about the particle or molecule: therefore at the start of the ‘race’, fluorescent markers can be added to the fluid, for example.
Hydrodynamic chromatography (HDC) is a well-known separation technique for particles and large molecules, but the resolution of current methods is far from optimal. HDC is usually applied in a fluid column, filled with non-porous particles that create, with the tiny spaces inbetween, the same effect as a narrow channel. On-chip separation results in a better resolution because the geometry is better defined than the pores between the particles in a conventional column, that are divided in a rather arbitrary way. Within just a few minutes Blom can, for example, fully separate little polystyrene balls. The new chip is particularly interesting for analysis of large molecules like polymers. For biomolecules, it works as well: for example analysis of DNA-components.
Wiebe van der Veen | alfa
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
21.08.2017 | Materials Sciences
21.08.2017 | Health and Medicine
21.08.2017 | Materials Sciences