Open menu

Nanotechnology General News

The latest news from academia, regulators
research labs and other things of interest

Posted: Jan 15, 2014

Microscopic fountain pen adds new functionality to AFM microscopy

(Nanowerk News) An AFM’s cantilever has a fine tip that can be used to map surfaces at the nanoscale. The movements of the tip are monitored using laser light reflected from the cantilever. If you could manufacture a hollow cantilever and pass a liquid through it, as happens in a fountain pen, then you could kill two birds with one stone. In addition to mapping surfaces, you could also use it to make highly localized measurements of the concentration of specific chemicals. This concept was the brainchild of Dr Peter Schön, a researcher who leads the “Enabling Technologies” Strategic Research Orientation at MESA+
microscopic fountain pen
The hollow cantilever of an AFM (tip is not shown now) is filled with mercury. The drop at the end is a chemical sensor.
Mercury
The liquid selected was mercury, as it has the ideal properties for this purpose, such as an extremely clean surface. The researchers have created a cantilever with a microscopic tube running through it. The tube’s lining has special mechanical properties, to contain the mercury as it is pumped through under high pressure (6 bar). Using this system, it has proved possible to create a perfect droplet at the tip. The droplet itself is the sensor, moreover it can easily be replaced in situ by a new sensor - the next droplet. It is also important that electrical current is only conducted through the mercury in the microscopic tube and not via parts of the cantilever, so as not to affect the measurement result. This goal, too, was successfully achieved.
Dual function
A sensor of such exquisite sensitivity can be used to measure concentrations of specific chemicals on biomolecules and biomembranes, for example. It can also be used in combination with AFM, to make highly localized measurements of corrosion while at the same time gathering other information about the surface in question. This makes for a particularly powerful combination of measurement methods.
Details of the “fountain pen’s” mechanism of action were recently published in “Analytical Chemistry”. The researchers are now focusing on ways of combining this technique with an AFM tip. They are also developing a technique for efficiently releasing the used mercury droplet to make way for a “clean” sensor.
In the course of this study Dr Schön cooperated with micromechanics experts from the Transducers Science and Technology group (which is also part of MESA+) and with a spinoff company, SmartTip (www.smarttip.nl)
Source: University of Twente
If you liked this article, please give it a quick review on reddit or StumbleUpon. Thanks!
Check out these other trending stories on Nanowerk:

Subscribe to a free copy of one of our daily
Nanowerk Newsletter Email Digests
with a compilation of all of the day's news.