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:4/28/2016)... BANGALORE, India , April 28, 2016 ... subsidiary of Infosys (NYSE: INFY ), and Samsung ... global partnership that will provide end customers with a ... and payment services.      (Logo: http://photos.prnewswire.com/prnh/20130122/589162 ... for financial services, but it also plays a fundamental part ...
(Date:4/15/2016)... , April 15, 2016  A new partnership ... more accurate underwriting decisions in a fraction of ... competitively priced and high-value life insurance policies to ... With Force Diagnostics, rapid testing (A1C, ... data readings (blood pressure, weight, pulse, BMI, and ...
(Date:3/31/2016)... 31, 2016  Genomics firm Nabsys has completed a ... Barrett Bready , M.D., who returned to the company ... technical leadership team, including Chief Technology Officer, John ... Steve Nurnberg and Vice President of Software and Informatics, ... Dr. Bready served as CEO of Nabsys ...
Breaking Biology News(10 mins):
(Date:5/18/2016)... , ... May 18, 2016 , ... ... Sciences Summer Camp at The University of Toledo. This two-day camp will take ... opportunity to explore the field of pharmaceutical sciences in preparation for a university ...
(Date:5/18/2016)... ... May 18, 2016 , ... STACS DNA Inc., the sample tracking ... and report sexual assault kit processing to help them save time and reduce errors. ... for kits to be processed and victims informed of results. Due to a previous ...
(Date:5/18/2016)... ... , ... The Academy of Model Aeronautics has been helping graduating seniors achieve ... of $1 million in awarded scholarships. , The AMA is happy to announce that ... nation has helped bring the total of AMA scholarships that have been given to ...
(Date:5/17/2016)... 2016 Haselmeier announces the launch ... approval by EMA, the European Medicines Agency. Originally launched ... company, the new pen version includes enhancements to further ... confidence to patients during use. Its enhanced ... to handle with a larger display window that improves ...
Breaking Biology Technology: