Destroying bacteria with bioactive packaging paper
Canadian researchers are developing a bioactive packaging paper that they believe will detect and kill pathogens present in food and drinks in a matter of seconds.
A consortium of 10 universities has formed the Sentinel Bioactive Paper Network, which is investigating biologically active chemicals to produce paper that can detect and deactivate bacteria and viruses such as E-coli and salmonella. This form of rapid pathogen detection has not been created before – normally samples take hours or days to be characterised in a lab. This would provide a cheap yet effective way of testing and decontaminating food or drinking water.
‘We are investigating a variety of detection technologies including antibodies, enzymes, bacteriophase and DNA aptamers. These are standard biochemical approaches to detecting pathogens. The challenge is to make them function on paper without special storage conditions and instruments,’ explains Professor Robert Pelton, Scientific Director of Sentinel, of McMaster University.
Using standard paper, the group is working on a bioactive ‘ink’ that could be printed, coated or impregnated onto or into paper using readily available techniques. Working with existing bacteria-sensing substrates, researchers are trying to identify key structural properties, such as porosity, surface chemistry and fibre type, to produce the right ink. Substances such as bleach would be added to destroy the bacteria.
‘Destruction is relatively easy,’ says Pelton. ‘Detection is more difficult.’ The ink would be specified to identify individual pathogens such as E-coli by binding to them and producing a detectable response.
Paper was chosen as the base material because it is environmentally friendly and offers technical advantages over plastic film, explains Pelton. ‘Paper can act as a filter to isolate small molecules from large particles or cells, perform chromatographic separation, and it is hydrophilic and thus more protein-friendly than plastic.’
The trickiest part of the programme has been incorporating the biologically active chemicals into paper, and keeping them alive during the drying and aging process. Thus far, ink-jet printing has proven the most promising as it is currently used for patterning other bioactive molecules onto substrates. Fuji-Dimatix, an ink jet manufacturer, and Sun Chemical, a producer of ink, have been working with Sentinel to develop this technique.
The Network, which is operating on a CAD$7.5m grant from Canada’s Natural Sciences and Engineering Research Council and three million dollars from industrial partners, see the paper being used in food packaging or paper towels. There are, however, some issues that need to be addressed, adds Pelton. Paper degradation in liquids means that wet strength resins will need to be added, which could interfere with bio-detection.
‘By 2010, we hope to have demonstrated paper-supported pathogen detection. We also expect that our industrial partners will bring the first bioactive paper products to the marketplace.’