Special coating could allow electronic implants to detect organ rejection


June 13, 2013

A silicon circuit coated with a protective layer and immersed in fluid that mimics human body chemistry

A silicon circuit coated with a protective layer and immersed in fluid that mimics human body chemistry

If physicians have a sufficiently-early warning that a patient’s body is rejecting a transplanted organ, then there’s a good chance that they can stop the process via medication. Implanted electronic sensors could serve to provide that warning as early as possible, and thanks to new research, they’re coming a step closer to practical use.

Most electronic devices utilize silicon semiconductors, which is fine in typical applications. Within the human body, however, charged electrolytes such as sodium and potassium are absorbed by silicon, altering its electrical behavior. As a result, the accuracy of readings from a regular silicon-based sensor can’t be trusted.

Other semiconductor materials could be used, although most of these are considerably more expensive and harder to work with than silicon.

Instead, Prof. Paul Berger of Ohio State University looked into a way of coating silicon semiconductors, so they simply can’t come into direct contact with electrolytes. He discovered that aluminum oxide seems to do the trick. Even after spending 24 hours submerged in an electrolyte-containing fluid that replicated the chemistry of the human body, test sensors coated with a layer of the material remained unaffected and fully functional.

It is now hoped that his research could lead to things like silicon sensors mounted on the end of a hypodermic needle, that could be inserted into a patient’s body adjacent to a transplanted organ. The sensor would then detect the presence and amounts of proteins that are produced in the earliest stages of organ rejection.

Berger also hopes that electrolyte-proof implantable electronics could even be used to replace damaged nerves. He’s additionally looking into the use of other coating substances, such as titanium.

A paper on the research was recently published in the journal Electronics Letters.

Source: Ohio State University

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away. All articles by Ben Coxworth
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