Paper device could detect deadly pathogens
Its first use will be to detect bacteria in milk and water, particularly in remote settings where farmers may not have the infrastructure to test products for pathogens.
The electrochemical diagnostic device, made of paper and tape, is only a concept at the moment. Frédérique Deiss, post-doctoral fellow, University of Alberta, will develop a prototype in the coming months.
Regular monitoring in remote areas
Deiss told FoodQualityNews.com she will be working with farmers near Nairobi, Kenya, to test the idea.
“This project was designed to answer a need in remote and low-resource settings, where regular monitoring of bacteria is very difficult and where the consequences of a bacterial outbreak can be even more dramatic,” she said.
“We will use a non-pathogenic strain of E. coli to design and develop the first prototype, and then translate to the pathogenic E. coli O157:H7. As we have previously successfully cultured the pathogens E.coli O157:H7 and Salmonella (Typhimurium LT) in paper-based devices, we believe the translation for those pathogens should be straight forward.
“In the long term, the platform should be adaptable to a broad range of bacteria.”
The paper device would be portable, self-contained and sealed, and cheap to make at less than 10 cents, Deiss said. Conductive ink on the paper would create an electrode to detect the presence of certain bacteria.
The electrodes in each device will be designed to detect a specific type of bacteria. It could detect low levels by culturing the bacteria in the device and re-analysing the sample at a later stage, once they have grown.
Field tests in Kenya
Deiss has received research funding from Grand Challenges Canada, a government supported initiative, under a programme for global health. The project is run in collaboration with the International Livestock Research Institute (ILRI) in Kenya, and on-field testing will take place in the country.
“The first target for our current platform is milk and water," Deiss said. "It is important to have a platform for samples of muddy water or milk, without special pre-treatment [which is not always available].
“Because of the nature of the paper, collection of samples from farm machinery, containers, or any solid surfaces will be very easy, and can be done by simply rubbing the open devices against the surface. You then close the device, culture it and perform the analysis, without any transfer of sample," she added.
“This is the key of this platform: to allow sample collection, culture and analysis in one single device, without needing to pre-treat the sample, transfer it multiple times, or even reopen the container. This limits the risk of errors and is safer for workers.
"Because it is made out of paper, it can be destructed easily and safely by burning it. This is useful in locations where the facilities to take care of biowaste are scarce.”
Deiss wants to create a prototype to detect non-pathogenic bacteria in the next six months. In a year she hopes to have a device that can detect pathogens such as E. coli. However, she was not able to say how long it would take for the idea to be replicated on a mass-scale.
“As with any platform for bio-analysis, it will depend a lot on field-tests and the approval of food and drug administrations and regulations,” she said. “We will have a better idea of the timeline once working prototypes are in use in Kenya.”
