A Natural Resource That Can Save Lives Canadian Bioactive Paper Network Chases a New Commercial Centre

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By Mike Pettapiece

McMaster University biochemistry-lab chief Yingfu Li remembers a time when he had a store-bought ham that just didn’t feel right. Something about the meat made him wonder if he and his family members might become victims of a food-borne illness.

“You could feel it was kind of sticky (indicating a possible bacterial-film presence),” he recalls. “It would be nice to have something, some product, for home use where you could put a little bit of (test) liquid (on the food) to see if it was okay to eat. . . . If you had something that cost maybe 10 cents or 20 cents . . . I would buy it.”

Which is exactly what Dr. Li and dozens of other Canadian researchers are doing to try to make the world a safer place. They are working on quick, reliable and inexpensive detector strips for homes, well-water areas, food factories and in Third World nations. The strips take advantage of a natural Canadian resource: paper made from tree pulp.

The need for such a handy paper-based product almost shouts from panicked headlines over the past several years.

There was the Walkerton tragedy in 2000, the SARS epidemic three years later in which 44 Canadians died, the 2008 listeriosis outbreak that claimed more than 20 lives and the more recent H1N1 influenza A crisis.

In March, a salmonella bacteria scare involving processed food containing hydrolyzed vegetable protein rippled across North America. The same month, there were more listeria deaths and illnesses. And a U.S. study concluded that food-borne illnesses cost the United States $152 billion annually in health care and other losses.

“Issues involving tainted food and water, resistant bacteria in hospitals, the global spread of disease and the threat of bioterrorism receive almost daily coverage in the Canadian media . . . ,” Dr. Robert Pelton wrote in a 2009 chemistry journal article.

“Inexpensive bioactive-paper assays could help control such outbreaks.”

Dr. Pelton is a chemical engineering professor at McMaster and scientific director of the Sentinel Bioactive Paper Network. He was a key inspiration years ago behind a plan for paper that would rehabilitate unsafe water. The paper would be added to unsafe water, causing the contaminants to bind to the cellulose fibers.

That idea sank for lack of funding but the concept of entrapping something stuck around. That led to bioactive molecules secured on a paper substrate -- a portable lab-on-a-chip platform. With such a cartridge, someone could detect a pathogen or toxic metal in water, such as E. coli or lead.

“I was in India (recently),” Dr. Pelton wrote in an email exchange from Portugal, where he is on a sabbatical. “And one reason was to scout out location where we could work with local scientists and engineers to evaluate bioactive paper-based water testing in rural communities.”

But the story is far bigger. Work is underway on several Sentinel platforms -- from detection of E. coli and listeria bacterium to virus-detecting hospital masks, from kits that detect greenhouse pathogens to research that seeks out neurotoxins that might be used as bioterrorism agents. Cellulosic paper remains the common denominator.

Sentinel has 19 member partners: 11 are Canadian universities, five are from industry and three come from government.

The network has been running on $8.5 million in funding from the Natural Sciences and Engineering Research Council of Canada and another $2.5 million from industrial partners and the Ontario Centres of Excellence.

The NSERC funding was originally designed to run until this fall. But new federal sector-specific research money that takes in the forest-products sector will extend Sentinel’s funds into 2015. And, said Dr. Pelton, Sentinel wants to create a national bioactive paper centre under the Centres of Excellence for Commercialization and Research. If that were to happen, it might mean millions more dollars.

Sentinel has a lot of competition. At Harvard University, for example, a research group has created a cheap paper-based diagnostic test for diseases or organ health, such as liver function. Other paper-research champions are in Finland and Australia. But Canada is an acknowledged world leader in this innovation.

Many different technologies come under the Sentinel umbrella. They vary depending on the potential use of the biosensors and the harmful substances they might contact.

But as a generic rule, they require a ‘capture agent,’ such as a bacteriophage or antibody that is engineered to recognize, bind and capture a specific pathogen, such as E. coli.

Perhaps one might even genetically engineer a bacteriophage (a virus that invades bacteria, using the host’s own machinery and energy to produce more phage), by inserting a colour gene into the phage DNA, so that it would fluoresce when the bacteria are destroyed.

Such paper bioassay strips are, in a way, akin to familiar detector strips like home pregnancy tests or glucose sensors. In its simplest form, a paper-based biosensor would signal contact with a pathogen by changing colour in one area, somewhat like pH-indicating blue litmus paper turns red when in contact with an acid.

Over the past several years, the network has taken research well beyond the proof-of-concept stage. For example, a spinoff company at the University of Guelph has developed a prototype bioassay kit that tests for a toxic pathogen, pythium aphanidermatum. Pythium devastates greenhouse vegetables and flowers.

The spinoff, called PatraTec, is also studying the potential of tests for E. coli or lead, two prevalent contaminants in drinking water. North America would be the most ready market but the benefit for less-wealthy nations is obvious. Such kits would not require the expensive testing and time delays inherent in using a laboratory.

“The initial market would be for people who depend on wells, for example in rural areas,” said Mercedes Salas, a co-founder of PatraTec. “It’s about peace of mind as well. You may know your source of water is safe but you just want to be sure.”

The science behind overcoming pathogens can be mind-boggling, taking in fields as diverse as nanotechnology, genetics, materials science, and biochemistry. At Guelph, for example, Christopher Hall, Canada Research Chair in Recombinant Antibody Technology, is introducing disease-fighting antibodies into plants.

Antibodies do not occur naturally in plants, so they enter a plant’s genetic code through the wonders of biotechnology.

He and others are investigating highly specific recombinant antibodies (rAb) that can be entrapped in cellulose. Such bioactive filters might be used to decontaminate greenhouse pathogens. In industrial applications, they might help purify nutraceuticals and pharmaceuticals.

Even developing paper bioassays is a small technology miracle in itself. In general, these sensors are paper-based cartridges that contain biologically active molecules. The technology uses a sol-gel method to entrap the molecules, such as enzymes, between biocompatible silica layers on the paper matrix.

Working with industrial partner Fujifilm Dimatix, a group led by John Brennan, Canada Research Chair in Bioanalytical Chemistry at McMaster, developed bioinks that could be printed onto a paper substrate. The detector biochemical reagents within the bioinks can remain active for some time as long as they are stored properly.

At the University of New Brunswick, investigator Huining Xiao is looking at food-process wrap and packaging that contains bioactive materials to inhibit E. coli activity. His research has shown that antimicrobial polymers or compounds can bind to paper.

Similarly, Ramin Farnood, at the University of Toronto, works with special inks to develop a paper that glows when electro-luminescent coatings are applied.

Such substances would react when exposed to certain pathogens or chemicals, warning consumers that a food product is contaminated.

If you can print such biosensors, you’re well along the way to scaled-up automation, which in turn moves you closer to commercial production. And the strips don’t have to be one-trick ponies, says Dr. Li. Researchers can develop reagents that can detect three or four pathogens. Reactions would be signalled at different spots on a strip.

Of course, the Sentinel technologies will need regulatory approvals from different government levels and agencies. Liability is “a huge issue,” notes Dr. Li. And the intellectual property is nothing without industrial partners and customers, and financing to take the various platforms to market.

“Canadian academics have always struggled at bringing research to commercialization,” Dr. Pelton commented via email. “A major objective of Sentinel Solutions, the commercialization network we hope to get funded, will be to bring economic paybacks to Canadian taxpayers.

We have already delivered good science and newly educated students with special interdisciplinary skills.”

Mike Pettapiece writes for the Golden Horseshoe Biosciences Network, based at McMaster University in Hamilton. He can be reached at: mikepettapiece@cogeco.ca