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
The balancing act: An enzyme that links endocytosis to membrane recycling
07.12.2016 | National Centre for Biological Sciences
Transforming plant cells from generalists to specialists
07.12.2016 | Duke University
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine