Navigation Links
Bacterium counteracts 'coffee ring effect'
Date:5/14/2013

Ever notice how a dried coffee stain has a thicker outer rim, while the middle of the stain remains almost unsoiled? This 'coffee ring effect' also occurs in other materials. Researchers from the Departments of Chemical Engineering and Chemistry at KU Leuven have now discovered how to counteract coffee rings with 'surfactants', i.e. soap. The key to the discovery was not a kitchen towel, but a bacterium that counteracts the coffee ring effect at the microscopic level. The findings were published in a recent edition of the leading journal Nature Communications.

When a coffee ring dries, its edges become noticeably darker and thicker. This occurs because the coffee particles move toward the edge of the stain while the water in the liquid evaporates. At a microscopic level, this coffee ring effect can also be seen in liquids with particles of other materials such as plastic and wood.

In various industrial applications applying an even coat of paint or varnish, for example the coffee ring effect can be particularly troublesome and scientists have long been seeking ways to counteract it. Raf De Dier and Wouter Sempels (Departments of Chemical Engineering and Chemistry) have now described a solution based on examples found in nature. De Dier and Sempels carried out experiments and calculations on nanomaterials as well as on a particularly promising bacterium, Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a dangerous bacterium that can cause infections in open wounds. "A Pseudomonas aeruginosa bacteria colony wants to find as large a breeding ground as possible. To avoid overconcentration on the edges of a wound when spreading itself during the drying-out process, the bacterium produces substances that counteract the coffee ring effect."

These surface-tension-disrupting substances are called surfactants. Detergents such as soap are also surfactants. "Add soap to a stain a coffee stain or any other stain and you will still get a coffee ring effect. But at the same time the soap causes a counterflow from the edge back towards the centre of the stain in such a way that the small particles material or bacteria end up in a kind of whirlwind. In this way, you get a more uniform distribution of particles as evaporation occurs."

"If we genetically modify the bacteria so they can no longer produce surfactants, the coffee ring effect remains fully intact. Our findings on Pseudomonas aeruginosa also apply to other bacteria. For the biomedical sector, this study contributes primarily to our understanding of a biological system." But surfactants could also potentially be added to nanomaterials, and that makes De Dier and Sempels' findings interesting for industry. "Surfactants are inexpensive. It won't be long before we start seeing them turn up in industrial applications."


'/>"/>

Contact: Wouter Sempels
wouter.sempels@chem.kuleuven.be
32-016-327-399
KU Leuven
Source:Eurekalert

Related biology news :

1. Virginia Tech and University of Tuscia lead team to unravel origin of devastating kiwifruit bacterium
2. Bacterium signals plant to open up and let friends in
3. Scientists reveal how natural antibiotic kills tuberculosis bacterium
4. Disappearing bacterium may protect against stroke
5. Scientists confirm that the Justinianic Plague was caused by the bacterium Yersinia pestis
6. An integrated pest management program for coffee berry borer in Colombia
7. Global prices of pollination-dependent products such as coffee could rise in the long term
8. Moderate coffee consumption offers protection against heart failure
9. New study suggests that Arabica coffee could be extinct in the wild within 70 years
10. Modern growing methods may be culprit of coffee rust fungal outbreak
11. Effects of environmental toxicants reach down through generations
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/15/2016)... , March 15, 2016 Yissum ... , the technology-transfer company of the Hebrew University, announced ... of remote sensing technology of various human biological indicators. ... raising $2.0 million from private investors. ... based on the detection of electromagnetic emissions from sweat ...
(Date:3/10/2016)... 2016 --> ... "Identity and Access Management Market by Component (Provisioning, Directory ... by Organization Size, by Deployment, by Vertical, and by ... The market is estimated to grow from USD 7.20 ... at a Compound Annual Growth Rate (CAGR) of 12.2% ...
(Date:3/8/2016)... , March 8, 2016   Valencell ... technology, today announced it has secured $11M in ... GII Tech, a new venture fund being launched ... additional participation from existing investors TDF Ventures and ... funds to continue its triple-digit growth and accelerate ...
Breaking Biology News(10 mins):
(Date:5/4/2016)... ... May 04, 2016 , ... PBI-Gordon Corporation is pleased ... Sales. , Doug began his career at PBI-Gordon in February 1988, after finishing ... wide variety of roles, ranging from customer service to national product manager, to helping ...
(Date:5/3/2016)... 3, 2016 The ... Discovery, Gene Expression) Lab-on-a-chip (IVD & POC, ... Diagnostics Centers), Fabrication Technology (Microarrays, Microfluidics) - ... market is expected to reach USD 17.75 ... in 2015, growing at a CAGR of ...
(Date:5/3/2016)... ... 2016 , ... In a list published by the Boston Business Journal, ... companies; a small percentage of the state's 615,000+ small businesses. The list examined companies ... revenue from 2012 to 2015. , As this award comes on the ...
(Date:5/3/2016)... CO (PRWEB) , ... May 03, 2016 , ... ... , announced the addition of Dr. Nancy Gillett to its Board of Directors. ... position, she served as Corporate Executive Vice President and Chief Scientific Officer. A ...
Breaking Biology Technology: