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 Fish recognize their prey by electric colors
13.11.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht The dawn of a new era for genebanks - molecular characterisation of an entire genebank collection
13.11.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

The dawn of a new era for genebanks - molecular characterisation of an entire genebank collection

13.11.2018 | Life Sciences

Fish recognize their prey by electric colors

13.11.2018 | Life Sciences

Ultrasound Connects

13.11.2018 | Awards Funding

VideoLinks
Science & Research
Overview of more VideoLinks >>>