The molecules in our body are in constant communication. Some of these molecules provide a biochemical fingerprint that can show how a wound has healed, whether a cancer treatment has worked, or whether a virus has invaded the body. If we can detect these signals in real time with high precision, we can recognize health problems faster and even monitor disease progression.

Now researchers at Northwestern University have developed a new technology that makes it easier to eavesdrop on our body’s internal conversations.

Although the body’s chemical signals are incredibly weak, making them difficult to detect and analyze, researchers have developed a new method that amplifies the signals more than 1,000 times. Transistors, the building block of electronics, can amplify weak signals to provide an amplified output. The new approach simplifies signal detection without complex and cumbersome electronics.

By amplifying weak biochemical signals, the new approach brings modern medicine one step closer to on-site diagnosis and real-time disease monitoring.

The study was published Saturday in the journal Nature Communication.

“If we can reliably measure biochemical signals in the body, we can incorporate these sensors into wearable technology or implants that take up little space, weigh less, and don’t require expensive electronics,” said Jonathan Rivney of Northwestern, senior author of the study. . “But getting high-quality signals remains a challenge. With the limited power and space inside the body, you have to find ways to amplify those signals.

Rivnai is a professor of biomedical engineering at Northwestern’s McCormick School of Engineering. Xudong Ji, a postdoctoral researcher in Rivnay’s lab, is the first author of the paper.

Although they transmit vital information full of diagnostic and therapeutic potential, many chemical sensors emit weak signals. In fact, medical professionals are often unable to decipher these signals without taking a sample (blood, sweat, saliva) and passing it through high-tech laboratory equipment. This equipment is often expensive and can even be found off-site. And returning results can take an unbearable time. But the Rivnai team aims to detect and amplify these latent signals before they leave the body.

Other researchers have discovered electrochemical sensors for biosensing using aptamers, which are individual DNA strands designed to bind to specific targets. After successfully binding to a target of interest, the aptamers act as an electronic switch by folding into a new structure that triggers an electrochemical signal. However, with aptamers alone, signals are generally weak and highly susceptible to noise and distortion unless tested under ideal and well-controlled conditions.

To avoid this problem, Rivnay’s team embedded an amplification component into a conventional electrode-based sensor and developed an electrochemical transistor-based sensor with a new architecture that can detect and amplify a weak biochemical signal. In this new device, the electrode is used to detect the signal, but the adjacent transistor is designed to amplify the signal. The researchers also included an integrated thin-film reference electrode to make the amplified signals more stable and reliable.

“We combine the local amplification power of the transistor with the reference signal you get using well known electrochemical techniques,” said Gee. “It’s the best of both worlds because we can stably measure aptamer binding and amplify it in situ.”

To test the new technology, Rivnai’s team turned to a common cytokine, a type of signaling protein that regulates the immune response and is involved in tissue repair and regeneration. By measuring the concentration of certain cytokines near the wound, researchers can assess how quickly the wound is healing, whether there is a new infection, or if other medical interventions are needed.

In a series of experiments, Rivnai and his team were able to amplify the cytokine signal by three to four orders of magnitude compared to conventional electrode-based aptamer detection methods. While the technology has performed well in experiments to detect cytokine signals, Rivnai says the detection scheme should be able to amplify signals from any molecule or chemical, including antibodies, hormones or drugs, where it uses electrochemical reporters.

“This approach is broadly applicable and has no specific use cases,” Rivnai said. Said. “The big vision is to apply our concept in implantable biosensors or wearable devices that can both detect and respond to a problem.”