System created to make paper biosensors

HAMILTON, Ontario, July 15 (UPI) -- Canadian scientists say they've created a technology similar to inkjet printing that can be used in making paper-based biosensors to detect harmful toxins.

McMaster University Associate Professor John Brennan and his research team say they've developed a method of printing a toxin-detecting biosensor on paper. The biosensor can be used to detect toxins that can cause food poisoning or that can be used as bioterrorism agents, the scientists said.

The researchers said their process involves formulating an ink like the one found in computer printer cartridges, but comprised of biocompatible silica nanoparticles. That ink is first deposited on paper, followed by a second ink containing an enzyme, with the resulting bio-ink forming a thin film of enzyme that is entrapped in the silica on paper.

When the enzyme is exposed to a toxin, reporter molecules in the ink change color in a manner corresponding to the concentration of the toxin in the sample, the scientists said.

The researchers said their goal is to provide a rapid, portable, disposable and inexpensive way of detecting harmful substances, including toxins, pathogens and viruses, without the need for sophisticated instrumentation.

The research is reported in the journal Analytical Chemistry.