Printable biosensors to speed diagnosis

The new platform from McMaster University is said to be the latest in a progression of paper-based screening technologies, which now enable users to generate a clear, simple answer in the form of letters and symbols that appear on the test paper to indicate the presence of infection or contamination in people, food or the environment.

In use, the biosensors could be incorporated into packaging that provides text warnings when food is contaminated with pathogens like E. coli and Salmonella, and patients could receive real-time diagnoses of infections such as C. difficile in their doctors’ surgeries.

“The simplicity of use makes the system easy and cheap to implement in the field or in the doctor’s office,” said John Brennan, director of McMaster’s Biointerfaces Institute, where the work was done with biochemist Yingfu Li and graduate student Carmen Carrasquilla.

“Imagine being able to clearly identify contaminated meat, vegetables or fruit. For patients suspected of having infectious diseases like C. diff, this technology allows doctors to quickly and simply diagnose their illnesses, saving time and expediting what could be life-saving treatments. This method can be extended to virtually any compound, be it a small molecule, bacterial cell or virus,” he said.

Although in its formative, stage, the research reportedly addresses a key problem facing current paper-based biosensing techniques which are labour-intensive, sometimes costly and inconvenient, and often difficult to mass-produce.

Using methods to produce “bio-inks”, researchers can now use conventional office ink-jet printers to print man-made DNA molecules with very high molecular weight on paper. The size of the DNA, which produces a signal when a specific disease biomarker is present, is enough to ensure it remains immobilised and stable. According to a statement from McMaster, the paper sensor emerges from the printer ready to use, like pH paper.

The implications are significant, said 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,” he said. “There are hundreds of possibilities.”