Monitoring Food Contamination in Real Time Using Printable Dnazyme Sensors

Foodborne illnesses have a pronounced impact on the global community, with cases numbering into the hundreds of millions annually and associated treatments costing tens of billions of dollars. Our inability to commercially detect food contamination in real-time is at the center of this crisis, as it places emphasis on static expiry dates that lack accuracy. These predicted dates not only fail to convey contamination, but also result in the disposal of mass amounts of edible food products. When contaminants are retroactively detected, measures such as food recalls are logistically complex and have massive economic ramifications. Existing methods for real-time detection of contaminants are expensive, require sophisticated equipment or offer poor detection capabilities, thus preventing commercialization. Additionally, detection requires packaging to be opened, making it unfeasible to monitor food products on an individual basis. Here, we propose a detection system centered upon the covalent immobilization of pathogen-specific RNA-cleaving fluorescent deoxyribozymes (RFDs) onto food wraps for real-time pathogen detection. These biomolecules exhibit a significant increase in fluorescence when exposed to their respective target. By functionalizing food wrap materials through plasma treatment, suitable crosslinkers can be used to bind amine modified RFDs onto the bulk wrap material. In particular, carbon dioxide plasma paired with carbodiimide chemistry presents itself as a well-studied immobilization approach that is applicable within the proposed sensing platform. Additionally, the use of microcontact printing to pattern RFD-crosslinker solutions onto food wraps presents a strategy suitable for industry scale-up. Given the transparency of food wrap materials and the printed sensor, this platform also overcomes the current need to open packaging for pathogen detection. Ultimately, we envision a patterned RFD barcode that provides multiplex detection of common foodborne pathogens. Use of a handheld fluorescence reader would allow for inexpensive, portable detection of food contamination along the entirety of the food production pipeline.