The conductive polymer PEDOT—poly(3,4-ethylene dioxythiophene)—offers the potential to serve an interface between electronic biomedical devices and nerve tissue. Unfortunately, the low mechanical stability and relatively limited adhesion of conjugated polymers like PEDOT to solid substrates can limit the lifetime and performance of devices employing them, and mechanical failure might also leave behind undesirable residue in the tissue.
Now, however, a research team led by the University of Delaware’s David Martin has reported the development of an electrografting approach to significantly enhance PEDOT adhesion on solid substrates. The breakthrough is documented in a paper published in Science Advances on March 3.
Martin, the Karl W. and Renate Böer Professor of Materials Science and Engineering, explained that the term electrografting describes a process in which organic molecules are electrochemically oxidized, followed by the formation of metal-organic bonds at the substrate-polymer interface.
Compared with other methods, surface modification through electro-grafting takes just minutes. The actual chemistry usually takes multiple steps, but Martin and his team have developed a simple, two-step approach for creating PEDOT films that strongly bond with metal and metal-oxide substrates, yet remain electrically active.
A variety of materials can be used as the conducting substrate, including gold, platinum, glassy carbon, stainless steel, nickel, silicon, and metal oxides.
“Our results suggest that this is an effective means to selectively modify microelectrodes with highly adherent and highly conductive polymer coatings as direct neural interfaces,” Martin said, as reported at Newswise.
The technology could be used in devices that enable a range of health interventions, from seizure detection and Parkinson’s disease therapy to functional artificial limbs, cochlear implants, and smart contact lenses.
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