New Electrode Coatings Enhance Neurotech Devices

by James Cavuoto, editor

January 2015 issue

The market for implanted neurotechnology devices stands to benefit from new advances electrode materials and coatings that promise to extend the capabilities of current devices. Products such as DBS leads, peripheral nerve stimulators, sensing electrodes, and cochlear implants could all take advantage of enhanced capabilities. Two midwestern U.S. firms have recently developed enhanced coating technologies for implanted electrodes.

One firm, University of Michigan spinoff Biotectix, recently introduced a new electroconductive polymer coating, called Amplicoat. Designed to enhance communication at the interface between human tissue and an electrode, Amplicoat overcomes the limitations of existing conductive coatings, including poor durability, difficult processing requirements, and limited performance. The new coating can be easily applied to a variety of metal electrodes.

“Amplicoat is a true breakthrough technology that provides a durable electrode coating that conducts both ionically and electronically, resulting in lower impedance and an expanded range for safe charge delivery,“ said Sarah Richardson-Burns, who co-founded Biotectix with Jeff Hendricks. The coating enables device electrode miniaturization, offering higher numbers of electrodes for a given-sized lead or device and providing greater tissue-sensing resolution as well as more localized stimulation control. It also enables higher signal fidelity, lower power requirements, and reduced stimulation thresholds.

Biotectix claims its materials technology offers neurostimulation and neurosensing several benefits, including improved signal fidelity and sensitivity for existing electrode designs with reduced signal-to-noise ratio. The coatings also offer reduced chronic tissue response and greater neuronal cell viability after implantation. And vendors can expect higher charge density and charge storage capacity, allowing for smaller electrodes and new low-profile lead designs. Internal testing at the company has demonstrated reduced electrode polarization of up to 95 percent, up to 400 percent higher charge delivery, and a 40 to 99 percent reduction in low-frequency impedance.

Biotectix was formed in 2007 through a joint venture between the University of Michigan and Allied Minds, a science and technology development and commercialization company. The company is currently working with customers to incorporate Amplicoat into their medical devices.

Amplicoat incorporates a surface modification technology developed by SurModics, Inc. of Eden Prairie, MN. SurModics’ PhotoLink technology uses light-activated chemistry to bond the coating to a substrate and quickly and evenly coats nearly all medical-grade materials. Because the coating is so thin, it results in insignificant dimensional change to the substrate.

SurModics technology has been used successfully on more than 150 commercial device applications in cardiovascular, diabetes, gastrointestinal, neurology, obesity, oncology, and urology.