A plastic transistor amplifies the signals of implantable sensors

Researchers at Northwestern University have developed a transistor that can amplify the signal generated by electrochemical sensors by 1,000 times.

The approach is broadly applicable and has no specific use case

The discovery may enable the development of highly sensitive implantable sensors that can measure small changes in electrochemical signaling in the body, which could allow clinicians to monitor tissue responses in near real time, instead of taking a blood sample on bulky and expensive laboratory equipment and getting results in 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 rapidly, and new techniques for detecting elusive biomarkers or monitoring the subtleties of biological processes in the body are constantly being developed. However, one unpleasant challenge has been the incredibly low signal of such sensors, which makes it difficult to monitor the process in real time with implanted devices. Instead, much of the diagnostic work involves taking a blood sample or biopsy and then completing laborious laboratory procedures with bulky equipment.

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

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

To solve this, researchers developed this transistor that can dramatically amplify the signal. The system also includes a thin-film reference electrode to help stabilize the signal. “This approach is broadly applicable and has no specific use case,” Rivnai said. “The big vision is to implement our concept into implantable biosensors or wearables that can sense a problem and then react to it.”

Source: Medgadget