Plastic Transistor Boosts Signals of Implantable Sensors

Researchers at Northwestern University have developed a transistor that can boost the signal created by electrochemical sensors by 1000-fold. The breakthrough may enable the development of highly sensitive implantable sensors that can measure tiny changes in electrochemical signaling in the body. This could allow clinicians to monitor tissue responses in near real time, instead of running a blood sample on bulky and expensive lab equipment and getting the results hours or even days later. Such technology could be used to monitor wound healing, for example, allowing clinicians to closely observe signals that reveal healing processes or the development of infection.

Biosensors are developing apace, and new techniques to detect elusive biomarkers or track the subtleties of biological processes in the body are constantly evolving. However, one sticky challenge has been the incredibly low signal of such sensors, which makes it difficult to monitor processes in real time with implanted devices. Instead, much diagnostic work involves taking a blood sample or biopsy and then completing arduous lab procedures with bulky equipment.

“If we could reliably measure biochemical signals in the body, we could incorporate those sensors into wearable technologies or implants that have a small footprint, less burden and don’t require expensive electronics,” said Jonathan Rivnay, one of the developers of the new technology. “But extracting high-quality signals has remained a challenge. With limited power and space inside the body, you need to find ways to amplify those signals.”

So far, the researchers have incorporated their signal-boosting transistor into an aptamer-based electrochemical sensor. Aptamers are single DNA strands that can bind to target molecules in the body. Once they bind, they change shape, affecting the electrochemical signal of the sensor they are a part of. However, to date, such sensors produce a weak signal that can easily be distorted by noise in the data.  

To address this, the researchers developed this transistor that can dramatically boost the signal. The system also includes a thin-film reference electrode that helps to stabilize the signal. “This approach is broadly applicable and doesn’t have a specific use case,” said Rivnay. “The big vision is to implement our concept into implantable biosensors or wearable devices that can both sense a problem and then respond it.”

Study in Nature Communications: Organic electrochemical transistors as on-site signal amplifiers for electrochemical aptamer-based sensing

Via: Northwestern University