Bioactive paper enlists llamas, tobacco to track down germs

Canadian researchers are working to develop specially treated paper that can help in the battle against SARS, listeriosis and other deadly pathogens.

Dubbed bioactive paper, products would be embedded with chemicals and agents that would recognize and kill specific pathogens, and alert humans to their presence.

"The man-on-the-moon vision is to have something like litmus paper in food packaging or air filters that changes colour or otherwise reacts to tell humans there's a pathogen problem," says Dr. Robert Pelton, a professor of chemical engineering at McMaster University in Hamilton and scientific director of the Sentinel Bioactive Paper Network.

The concept was conceived by Pelton and three other scientists in the wake of the SARS epidemic that swept through Toronto in 2003. Sentinel hopes to develop bioactive paper models that can decrease the threat from communicable diseases, food-borne illnesses and water contamination, while also boosting Canada's forest products industry.

The idea has piqued the interest of a number of backers. The Sentinel consortium comprises researchers at 10 universities across Canada, government agencies and nine business partners. It is working with a five-year, $12-million grant from government and industry.

FP Innovations, a Montreal-based not-for-profit forest research institute, and a Sentinel industry partner, is looking for new concepts such as bioactive paper to revive the Canadian pulp-and-paper industry's flagging fortunes, says Francois Drolet, a scientist in the institute's product performance group.

"There's a crisis in the industry as there's been a decline in demand, especially for newsprint, and there's more competition from countries like Brazil, which have lower labour costs," he says. "It makes sense to shift to products created with Canadian technology that have higher profit margins."

The ultimate objective is to develop bioactive paper that works alone to detect and neutralize pathogens without extra equipment, processing, or laboratories, says Pelton. "We haven't achieved that yet, but we've solved some parts of the problem."

There are many agents that can be used in paper to kill germs, he says. Kimberley-Clark, for example, produces antiviral Kleenex that is treated with citric acid and sodium lauryl sulphate - two common household ingredients - that are activated by the moisture of a runny nose. About 99 per cent of the four most common cold viruses are killed within 15 minutes, according to the company.

Sentinel's bioactive paper vision is far more complex, as there is no one chemical or agent that kills all pathogens, nor does antiviral Kleenex detect or alert people to the presence of specific viruses.

Cracking the code with llamas, tobacco

Finding ways to detect different pathogens is a fundamental step in the group's efforts to develop a marketable product.

"We have to selectively trap the target pathogen, which means finding the nasty ones amongst a sea of less nasty ones," says Pelton.

There are ways to narrow the search for the needle in the haystack, he says. There are only a few really dangerous pathogens in any given geographic region or environments such as hospitals, so researchers only need to find ways to detect the top three or four, not thousands, to deal with most outbreaks.

'One of the issues with putting antibodies on paper is that they must be stable and last a long time sitting in store shelves. Llamas produce special antibodies that don't decompose when they dry out or require refrigeration.' Robert Pelton, McMaster U./Sentinel

Researchers are also working to find ways to produce the large quantities of antibodies needed to treat paper, he says. Once found, inexpensive processes such as inkjet printing can be used to mass-produce bioactive paper.

Sentinel is using an inventive approach to cracking the detection problem by embedding antibodies that counteract specific pathogens in paper. To accomplish this, researchers are using llamas to produce the antibodies.

"One of the issues with putting antibodies on paper is that they must be stable and last a long time sitting in store shelves," Pelton says. "Llamas produce special antibodies that don't decompose when they dry out or require refrigeration."

The animals are injected with a target pathogen, which stimulates their immune systems to generate antibodies to combat it. "We isolate the DNA that generated the antibody from their blood, and then genetically engineer that DNA in tobacco plants."

Why tobacco?

Antibodies could be produced in huge fermentation vats, but they can also be grown in genetically engineered crops, he explains. But there's a danger in working with food crops such as corn if genetically altered plants escape into the wider environment and contaminate the food supply, he adds.

"The advantage of tobacco is that we don't eat it, and there's a dying tobacco industry in Ontario that wants to produce something that has higher value."

Detection

Sentinel is getting very close to solving the detection problem, Pelton adds. "We have demos where we can detect some pathogens such as E. coli, but we can only detect relatively high levels of bacteria."

But researchers are still working on the reporting problem, he says.

"We still don't have something that changes colours or otherwise alerts humans - we have to do something like treat and wash the paper with other chemicals," Pelton says. "It's like traditional photo processing with various baths, but what we want is an instant Polaroid."

Bioactive paper that requires extra steps would still be useful in hospital settings, he adds. "They do have labs, so we could see a system where they swab an area and then drop in some chemicals to check for signs of contamination. We could see that in the near future."

Creating bioactive paper is ultimately about assembling components from various existing technologies to develop viable new products, he says. "We're not inventing these things. Our idea is just to take the low-hanging fruit and try to figure out how to put it on paper inexpensively."

Transforming vision into profit

There are commercial possibilities in bioactive paper that may materialize within five to 10 years, says FP Innovations' Drolet. One class of product lies in diagnostic paper. In the packaging industry, this could be absorbent paper to wrap meat or cardboard boxes that give a warning if food is contaminated.

Apotential application of Sentinel's research ispathogen-trapping paper that could be used in masks during infectious outbreaks such as SARS, and in water and air filters.

"With the speed at which products from places like China get here, signalling contaminants in food is a huge application," Drolet says.

Another category is pathogen-trapping paper that could be used in masks during infectious outbreaks such as SARS, and in water and air filters, he says. "There's a large market for filters in buildings."

While these products won't replace lost newsprint in terms of volume, they may generate significant revenue, Drolet says. "These are higher-value products where you make more money on a single sheet of paper."

Other industry partners are less bullish.

"There's a lot of interesting research coming out of Sentinel, but it's not clear if it has commercial potential," says Stephen Bryant, group manager of biotechnologies at Buckman Laboratories, a Memphis, Tenn.,-based manufacturer of industrial biocides. "You have to make the science work in a profitable product."

But many wildly successful products, such as 3M's Post-it notes, came out of research that initially appeared to have no commercial application, he adds. "For us, participating in Sentinel is an opportunity to connect with university findings to see if there's a match in our business. If we don't make these investments, where are the new products and technology of the future going to come from?"

The author is a Canadian freelance writer.