Featured Research

from universities, journals, and other organizations

Sticky Mussels Inspire Biomedical Engineer Yet Again

Date:
October 20, 2007
Source:
Northwestern University
Summary:
Mussels are well known for sticking to virtually all inorganic and organic surfaces and doing so with amazing tenacity. A material that mimics the strength of the bonds has already been created. Now scientists have produced a versatile coating method that mimics the mussels' ability to attach to a wide variety of objects. A broad variety of materials can be coated and functionalized through the application of a surface layer of polydopamine.

Shown above are mussels attached to a rock (left) and Teflon (right). Mussels' ability to adhere to all inorganic and organic surfaces inspired a new multifunctional coating strategy.
Credit: Image courtesy of Northwestern University

Mussels are delicious when cooked in a white wine broth, but they also have two other well-known qualities before they're put in a pot: they stick to virtually all inorganic and organic surfaces, and they stick with amazing tenacity.

Northwestern University biomedical engineer Phillip B. Messersmith already has developed a material that mimics the strength of the bonds; now he has produced a versatile coating method that mimics the mussels' ability to attach to a wide variety of objects.

Messersmith and his research team, in a study to be published in the Oct. 19 issue of the journal Science, report that a broad variety of materials can be coated and functionalized through the application of a surface layer of polydopamine.

Potential applications of the simple and inexpensive method include flexible electronics, such as bendable and flexible displays, biosensors, medical devices, marine anti-fouling coatings, and water processing and treatment, such as removing heavy metals from contaminated water.

Key to the coating method is the small molecule dopamine, commonly known as a neurotransmitter. Dopamine, it turns out, is a good mimic of the essential components of mussel adhesive proteins, and the researchers use it as a building block for polymer coatings. (Dopamine itself is not found in mussels.) So, like a mussel, Messersmith's coating sticks to anything.

"This is an astonishingly simple and versatile approach to functional surface modification of materials," said Messersmith, professor of biomedical engineering at Northwestern's McCormick School of Engineering and Applied Science, who led the research. "We dissolve dopamine, which we buy at low cost, in a beaker of water exposed to air. We adjust the water's pH to marine pH, about 8.5, put in an object and several hours later it's coated with a thin film of polydopamine. That's it."

Solid objects of any size and shape can be immersed in the solution. (The dopamine solution is very dilute -- only two milligrams of dopamine per one milliliter of water.) At marine pH, there are chemical changes in the dopamine molecule that result in polymerization of the molecules together to form a polymer, polydopamine, which coats the object. The polymer is fairly similar to what is found in the mussel adhesive protein.

And to make things more interesting, the polydopamine coating, in turn, provides a very chemically reactive surface onto which the researchers can deposit a second coating. And because the surface is so reactive in so many different ways, a wide variety of second coatings can be applied.

"We take advantage of that reactivity to apply the second layer," said Messersmith. "As a simple example, I could put an iPod in the dopamine solution, and a thin polydopamine coating would form. Then I could take it out and put it in a metal salt solution and form a coating of copper or silver."

This second coating, depending on what it is, promises to take researchers and industry in multiple directions as far as applications go. In addition to cladding objects with metal coatings, this includes inhibiting biofouling of materials (such as for medical devices), engineering surfaces to support biospecific interactions with cells (such as for culture and expansion of stem cells) and applying self-assembled monolayers to nonmetal surfaces (such as for biosensors).

Messersmith and his colleagues tested the two-step process on 25 different substrate materials (but not an iPod) with a wide range of characteristics representing all major classes of materials, from hydrophobic to hydrophilic, from inorganic to organic, as well as the traditionally difficult material Teflon, all with positive results. They then demonstrated deposition of metal and organic coatings and self-assembled monolayers onto the polydopamine coating.

"Existing methods for modifying material surfaces are fairly restricted to specific materials -- what works well on glass would not work well on gold," said Messersmith. "Our method is a much more general strategy for a variety of surfaces. We haven't found a material to which we can't apply polydopamine."

In addition to Messersmith, other authors of the paper, titled "Mussel-Inspired Surface Chemistry for Multifunctional Coatings," are Haeshin Lee (lead author) and Shara M. Dellatore, both graduate students, and William M. Miller, professor of chemical and biological engineering, all from Northwestern.


Story Source:

The above story is based on materials provided by Northwestern University. Note: Materials may be edited for content and length.


Cite This Page:

Northwestern University. "Sticky Mussels Inspire Biomedical Engineer Yet Again." ScienceDaily. ScienceDaily, 20 October 2007. <www.sciencedaily.com/releases/2007/10/071018142509.htm>.
Northwestern University. (2007, October 20). Sticky Mussels Inspire Biomedical Engineer Yet Again. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2007/10/071018142509.htm
Northwestern University. "Sticky Mussels Inspire Biomedical Engineer Yet Again." ScienceDaily. www.sciencedaily.com/releases/2007/10/071018142509.htm (accessed August 1, 2014).

Share This




More Matter & Energy News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
7 Ways to Use Toothpaste: Howdini Hacks

7 Ways to Use Toothpaste: Howdini Hacks

Howdini (July 30, 2014) Fresh breath and clean teeth are great, but have you ever thought, "my toothpaste could be doing more". Well, it can! Lots of things! Howdini has 7 new uses for this household staple. Video provided by Howdini
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins