Pathogen-sensing paper - from an inkjet printer

Imagine if food packaging could warn consumers if the product inside was contaminated with pathogens like E. coli and Salmonella. This concept could soon be a reality, after researchers at McMaster University developed a new way to print paper biosensors.

The result of the research would give consumers a clear, simple answer in the form of letters and symbols that appear on the test paper to indicate the presence of food contamination.

“Imagine being able to clearly identify contaminated meat, vegetables or fruit. For patients suspected of having infectious diseases like C. difficile, this technology allows doctors to quickly and simply diagnose their illnesses, saving time and expediting what could be life-saving treatments,” said John Brennan, director of McMaster’s Biointerfaces Institute, who conducted the research with biochemist Yingfu Li and graduate student Carmen Carrasquilla.

“This method can be extended to virtually any compound, be it a small molecule, bacterial cell or virus.”

Current paper-based biosensing techniques are labour-intensive and often expensive, and can be difficult to mass produce.

Using state-of-the-art methods to produce ‘bio-inks’, researchers can now use conventional office inkjet printers to print man-made DNA molecules with very high molecular weight on paper, much like printing a letter in an office. The sheer size of the DNA - which produces a signal when a specific disease biomarker is present - is enough to ensure it remains immobilised and therefore stable. The paper sensor emerges from the printer ready to use, like pH paper.

The implications are significant, says Brennan, since the new technology could be used in many fields where quick answers to important questions are critical.

“We could conceivably adapt this for numerous applications, which would include rapid detection of cancer or monitoring toxins in the water supply. There are hundreds of possibilities,” said Brennan.

The research was published in the journal Chemistry