Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Defense mechanism employed by algae can effectively inhibit marine fouling

03.02.2017

Cerium dioxide nanoparticles block communication between bacteria and prevent the formation of biofilms

Chemists at Johannes Gutenberg University Mainz (JGU) have developed a method that reliably hinders hazardous seawater fouling and is effective, affordable, and easy on the environment. Fouling can occur, for example, as the result of the growth of bacteria, algae, or mollusks in harbor facilities, on boat hulls, and aquaculture netting. The resultant damage and consequential costs can be significant. It is estimated that these are equivalent to 200 billion dollars annually in the shipping industry alone. Protective coatings applied to vessels usually contain copper-based biocides. These have the disadvantage that they harm the environment while resistance to them can also develop. In order to find an alternative, the Mainz-based research team of Professor Wolfgang Tremel decided to simulate a defense mechanism employed by algae and established that cerium dioxide nanoparticles can effectively prevent fouling. This discovery could contribute towards the production of new protective coatings that are much less environmentally harmful than the hull coatings in use to date.


Illustration of the mode of action of bioinspired underwater paints: Like the natural enzyme vanadium bromoperoxidase cerium dioxide nanoparticles act as a catalyst for the formation of hypobromous acid from bromide ions (contained in sea water) and small amounts of hydrogen peroxide that are formed upon exposure to sun light yielding reduced biofilm formation.

ill./©: Tremel research group, JGU

Marine algae utilize secondary metabolic products in order to provide themselves with a form of chemical defense against micro-organisms and predators. These halogenated secondary metabolites specifically prevent bacterial biofilms, other algae, and even barnacles becoming attached to and developing on larger formations of algae, sponges, and other creatures. Halogenated compounds produced by the red seaweed Delisea pulchra, for instance, inhibit bacterial fouling but are neither toxic nor growth-retarding. Instead, they scupper what is known as quorum sensing, i.e, a system used by bacteria to communicate with the help of messenger substances that results in the formation of biofilms. The structures of the halogenated compounds synthesized by seaweeds are similar to those of these substances so that they cause a blockade of the bacterial receptors and suppress the switchover of bacterial gene regulation to biofilm formation. This form of interference with bacterial gene regulation is also of pharmaceutical interest as it is known that pathogenic bacteria can protect themselves against attack by the immune system and the effect of antibiotics by forming biofilms, for instance on the epithelium of the respiratory system.

This natural defense process has been mimicked by the Mainz-based team of chemists using nanoparticles of cerium dioxide. "Field tests have shown that cerium dioxide is an ecologically acceptable alternative to cuprite, a substance that is used as a biocide together with copper thiocyanate and copper pyridine at concentrations of up to 50 percent in anti-fouling coatings," explained Professor Wolfgang Tremel of JGU’s Institute of Inorganic Chemistry and Analytical Chemistry. But such copper compounds are toxic and accumulate in the environment. This is why some countries, such as Canada and Denmark, have imposed strict limitations on the use of copper-based anti-fouling coatings.

A cost-effective and environmentally-friendly alternative to cupriferous biocides

"All modern catalytic converters in vehicles use cerium dioxide. It is non-toxic and chemically extremely stable," added Karoline Herget, who wrote her doctoral thesis on the project. She is convinced that cerium dioxide is a practical and cost-effective alternative to conventional biocides.

Cerium dioxide is an oxide of the rare earth element cerium and a by-product of the process of extraction of rare earth metals. Despite belonging to the family of rare earth elements, cerium itself is not particularly scarce. Its cost is thus comparable with that of cuprite (copper(I) oxide), although it is effective in far lower quantities. "What we have here is an environmentally compatible component of a new generation of anti-fouling coatings that simulate the natural defense systems employed by marine organisms. What is important is that it is effective not only under laboratory conditions but also when actually used in the aquatic environment," Herget concluded. Steel panels with cerium oxide coatings can be exposed to seawater for weeks on end without becoming covered by bacteria, algae, mollusks, or barnacles. Reference samples with conventional water-based coatings develop massive fouling over the same time period.

Biofilms are around virtually everywhere. They are present in drinking water pipes and clarification plants, in ground water, water filtration and cooling systems, on practically all surfaces such as food packaging, door handles, push buttons, keyboards, and other elements made of plastic, and, when it comes to medicine, they also develop in catheter tubes. The main problem in connection with combating these using biocides and antibiotics is the risk of the development of resistance. This drawback could be effectively circumvented in an ecologically acceptable manner by applying surface coatings of cerium dioxide particles. This innovative technique thus has potential applications in the fields of boat and exterior coatings, roof coverings, outdoor textiles, polymer membranes used for desalination, enclosures employed in aquaculture, and in many plastic components.

The research project was undertaken in cooperation with BASF and the results have been published in the journal Advanced Materials.

Photos/Illustrations:
http://www.uni-mainz.de/bilder_presse/09_anorgchemie_fouling_cer_01_eng.jpg
Illustration of the mode of action of bioinspired underwater paints: Like the natural enzyme vanadium bromoperoxidase cerium dioxide nanoparticles act as a catalyst for the formation of hypobromous acid from bromide ions (contained in sea water) and small amounts of hydrogen peroxide that are formed upon exposure to sun light yielding reduced biofilm formation.
ill./©: Tremel research group, JGU

http://www.uni-mainz.de/bilder_presse/09_anorgchemie_fouling_cer_02.jpg
Boats moored in the offshore immersion site (Belgium, Maas) to test the effect of variously coated steel plates
photo/©: R. Schröder, Tremel research group, JGU

http://www.uni-mainz.de/bilder_presse/09_anorgchemie_fouling_cer_03_eng.jpg
Commercially available antifouling paint (hard and soft formulation) with and without cerium dioxide nanoparticles was applied to stainless steel plates. Several control plates (stainless steel, native paint formulations and paint formulations with copper oxide) are displayed as well. The plates were attached statically to a boat bridge with direct exposure to fresh water. After 52 days, the control plates without cerium dioxide nanoparticles showed heavy fouling. In contrast, the plate with the cerium dioxide coating did not. Cu2O, the current gold standard, is added in commercially available coatings with a portion by weight of up to 50 percent.
photo/©: Tremel research group, JGU

Original publication:
Karoline Herget et al.
Haloperoxidase Mimicry by CeO2−x Nanorods Combats Biofouling
Advanced Materials, Online-Publikation, 29 November 2016
DOI: 10.1002/adma.201603823

Contact and further information:
Professor Dr. Wolfgang Tremel
Institute of Inorganic Chemistry and Analytical Chemistry
Johannes Gutenberg University Mainz
55099 Mainz
phone +49 6131 39-25135
fax +49 6131 39-25605
e-mail: tremel@uni-mainz.de
http://www.ak-tremel.chemie.uni-mainz.de

Weitere Informationen:

http://onlinelibrary.wiley.com/doi/10.1002/adma.201603823/abstract ;
http://www.uni-mainz.de/presse/15482_ENG_HTML.php – press release "Inspired by nature: Paints and coatings containing bactericidal agent nanoparticles combat marine fouling", 2 July 2012

Petra Giegerich | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>