Pathogens on Paper

Passing the litmus test

September 30, 2009 – In the past decade, Canada has experienced more than its fair share of biologically related incidents: the Walkerton tragedy in 2000, the SARS epidemic in 2003 and last year’s Listeriosis outbreak.

In 2003, a small group of researchers discussed the possibility of using paper to detect and eliminate potentially harmful pathogens.

The group, led by researcher Dr. Robert Pelton of McMaster University and funded by the Natural Sciences and Engineering Research Council (NSERC), began to develop a paper that could detect and destroy bacteria and viruses safely, without requiring the use of a lab.

That vision has developed into the  SENTINEL Bioactive Paper Network, and has since grown to over 25 professors from 10 universities across Canada. The network includes experts in the fields of engineering, chemistry, biochemistry, microbiology and food science.

“The goal,” says Dr. Pelton, “is a paper with built-in technology that will change colour in response to pathogens, like litmus paper reacts to acids and bases.”

This technology could profoundly change pathogen detection, allowing for gowns, gloves and masks in hospitals that would identify and destroy harmful pathogens as they appear. It could also pave the way to creating inexpensive and effective water treatment, as well as the quick detection and destruction of contaminants in the meat packaging and processing industry.

To speed its development, NSERC, through its Strategic Network Grants Program, has committed almost $8 million (from 2005 to 2010) to the SENTINEL Bioactive Paper Network for the creation of bioactive paper.

For bioactive paper to work effectively, the pathogen must first be captured and then reported to the observer. As Dr. Pelton says, like most innovations, it is easier said than done, since a capture agent (usually a bacteriophage or antibody) must be engineered to recognize, bind and capture a specific pathogen. Reporting a capture event without instrumentation is a major challenge and a large part of the network’s research. Using a bacteriophage is one approach under investigation.

“A bacteriophage is a virus that only attacks bacteria,” says Dr. Pelton. “It looks like a lunar lander, with spindly legs and a capsule on top which contains its DNA.”

For reporting purposes, a bacteriophage could be genetically engineered to fluoresce once the bacteria are destroyed, by inserting a colour gene into the phage DNA.  However, Dr. Pelton says that the technology is still in its early stages.

Another issue is that the finished components must be placed on paper in a stable form that can survive until their eventual use. “This is a big problem,” says Dr. Pelton. “Biochemistry is primarily a wet process and protein-based detectors such as antibodies or enzymes are easily deactivated by heat, light or drying on surfaces.”

While there are numerous hurdles to making this technology work, Dr. Pelton and the entire network are optimistic about this unique technology. “Bioactive paper has almost limitless potential to make hospitals safer, meat less dangerous and the ability to provide water treatment in a cheap and effective way.”