Wearable Sensors Detect Pathogens, Toxins

Tufts University, Medford, MA

A drone in which the fuselage is embedded with sensor material. (Image: SilkLab)

Researchers at Tufts School of Engineering have developed a method to detect bacteria, toxins, and dangerous chemicals in the environment with a biopolymer sensor that can be printed like ink on a wide range of materials — including wearables.

Using an enzyme akin to one found in fireflies, the sensor — which is based on computationally designed proteins and silk fibroin extracted from the cocoons of the silk moth Bombyx Mori — glows when it detects these invisible threats.

The biopolymer sensor can also be embedded in films, sponges, and filters, or molded like plastic to sample and detect airborne and waterborne dangers or used to signal infections in our bodies.

The sensors currently require a spray with a non-toxic chemical after being potentially exposed to bacteria, toxins, and dangerous chemicals. If the target is present, then the sensor generates light; the intensity of emitted light provides a quantitative measure of the concentration of the target.

“The combination of lab-designed proteins and silk is a sensor platform that can be adapted to detect a wide range of chemical and biological agents with a high degree of specificity and sensitivity,” said Professor Fiorenzo Omenetto, Director, Tufts SilkLab. “For example, SARS-CoV-2 and anti-hepatitis B antibodies can be measured at levels that approach at-home assays.”

The sensing element is modular, so developers can swap in newly designed proteins to capture specific pathogens or molecules to measure, while the light emitting mechanism remains the same.

“Using the sensor, we can pick up trace levels of airborne SARS-CoV-2, or we can imagine modifying it to adapt to whatever the next public health threat might be,” Omenetto said.

The sensors can assume a variety of forms, as evidenced by the research team creating viral sensing drones in which their fuselage was embedded with the sensor material. During flight, the propellers direct airflow through the porous body of the drone, which can be examined after landing. The drones, which in this case reacted to airborne pathogens, could enable monitoring environments from a safe distance.

The researchers tested the shelf life of materials embedded with SARS-CoV-2 sensors after storing them at 60 °C for four months and found very little performance change.

“This means we can manufacture, distribute, and store these sensing interfaces for long periods of time without losing their sensitivity or accuracy and without the need for refrigerated storage, which is remarkable due to the fact that they are made of protein,” said Luciana d’Amone, project co-lead. In addition, it could expand the sensors’ formats.

“For example, you could make surgical masks capable of detecting pathogens, package them in boxes, and use them over time just like conventional masks,” said d’Amone. “We also showed that you can print the sensor inside food packaging to track spoilage and toxins. You can modify so many products that we use every day to include sensing, and store and use them as you normally would.”

The team envisions sensor applications ranging from personal and patient monitoring and infection control in healthcare settings to environmental sensing in home, workplace, military, and disaster areas.

For more information, contact Mike Silver at This email address is being protected from spambots. You need JavaScript enabled to view it.; 617-627-0545.