Botulism outbreak highlights need for improved safety. A solution may already exist
Printable ink sensors on food packaging and test strips can detect pathogens and toxins
image: A jar lid with printed silk-based polymer sensors that can detect the presence of botulinum toxin
Credit: Fiorenzo Omenetto
Recent news from Italy has put the spotlight on the continuing risk of botulism outbreaks caused by contaminated food supplies. An innovation by scientists who created low-cost ink-based sensors that can be printed directly on packaging materials could provide a significant advance in preventing such outbreaks.
Safety measures in preparation and packaging exist to reduce the risk of contamination by pathogens such as Clostridium botulinum, which produces a potentially lethal toxin. However, a full measure of food safety cannot exist unless there is real time monitoring of individual products on store shelves.
Researchers at the Tufts University Silklab, in collaboration with (Nobel Laureate) David Baker and his team at the University of Washington’s Institute for Protein Design, developed a biosensing ink that can detect botulinum neurotoxin with high specificity. It is easy to read as a simple change in color.
Described in the journal Advanced Materials in 2022, the printable ink based on a soluble silk protein has embedded within it lab-designed protein ‘switches’ which bind to specific molecules, such as toxins or surface markers on pathogens like Sars-CoV-2, and instantly change color. Printed on the inside of a jar lid, for example, it can tell the consumer if the product they are about to consume is sterile or contaminated.
“Watching the botulism outbreak unfold in Italy has made it more obvious that there are gaps in the food safety regimen,” said Fiorenzo Omenetto, professor of engineering at Tufts University and director of Silklab. “There is really nothing in place to inform the consumer at the point of use if the product is actually safe. Our silk-based ink can provides a low-cost, and easily applied sensing tool that could be printed on paper test strips or packaging to monitor food safety in real time,”
At the heart of the system are computationally designed protein switches that undergo a “shape shift” upon binding to specific targets, such as botulinum toxin. These switches are stabilized and preserved in re-polymerized silk, which acts as both a carrier and protective matrix.
“The ability to sense a molecule as potent and dangerous as botulinum toxin using a food-safe printable ink opens up new possibilities for low-resource diagnostics,” said Dr. Giusy Matzeu, co-inventor and senior researcher at SilkLab. “It’s an elegant solution that could make an immediate impact.”
The same platform can be rapidly adapted to detect other toxins, pathogens, or chemical agents by swapping the protein recognition element—paving the way for a modular library of silk-based printable sensors for future public health and security challenges.