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 restri
|Contact: Megan Fellman|