Conductive Polymer Coating Enhances Electrode Performance

A new conductive coating could enable electrode miniaturization and more localized stimulation control for patients with heart disease, cochlear implants, and other needs.

The novel coating, called Amplicoat, is made of Poly 3,4–ethylenedioxythiophene (PEDOT), a proprietary surface modification polymer coating with inherently conductive properties that can be used for shielding, drug delivery, or electrode or surface modification in all types of medical devices, including implantable devices and sensors. Intended uses of the coating include electrodes intended for neurostimulation devices, cardiac pacing, electrophysiology recordings, cochlear implants, and gastrointestinal (GI) recording and stimulation.

According to Amplicoat developer, Biotectix (Ann Arbor, MI, USA), electrodes coated the conductive polymer coating can be up to 80% smaller than traditional metal electrodes. This would allow for higher numbers of electrodes for a given-sized lead or device, as well as provide greater tissue-sensing resolution, more localized stimulation control, higher signal fidelity, lower power requirements, and reduced stimulation thresholds. From an environmental point of view, smaller electrodes would also reduce the need for gold and other precious metals.

“It’s much more similar to the tissue in our body than what’s currently available. It’s softer; it transfers charge both electrically and ionically. It allows you to target the response you’re looking for without producing a lot of unwanted side effects,” said Jeff Hendricks, founder and director of engineering at Biotectix. “We believe this strong and robust coating will help to enable many diverse applications, whether for long-term implants or short-term procedures, and will help to push medical device technology forward to encourage miniaturization and less invasive processes.”

PEDOT, which is positively charged, generally has polystyrene sulfonate paired with it as its negative counter in industrial applications, such as a static reducer in electronics packaging. A hydrophilic coating developed by SurModics (Eden Prairie, MN, USA) which serves as substitute for the polystyrene sulfonate, adds the needed durability and extended lifetime of at least 10 years for using PEDOT in implanted devices.

Related Links:
Biotectix
SurModics