Polymer brushes for sensing in food systems: Opportunities and challenges span from organophosphorus pesticide to pathogen detection

Polymer brushes are tethered nanomaterial surface coatings that have important applications in smart release systems, pollutant degradation technologies, and sensors. Most applications of brushes have been in the medical domain, but there is an exciting opportunity to develop responsive interfaces for sensor applications in food systems. In this review article, we summarize common synthesis approaches as well as general mechanisms for stimulus-response behavior. We discuss emerging opportunities and challenges for polymer brush sensors in detection of six key targets in the food system: VOCs, nutraceuticals and bio-active compounds, pesticides, inorganic phosphates and other food additives, proteins such as allergens, and pathogens. Specific to food systems, major challenges include sample (matrix) complexity, material sustainability for sensor development, scalability of polymer brush synthesis, regulatory approval, and trust/transparency in new automated decision support approaches. Here, we also highlight general opportunities and challenges in polymer brush sensing related to advancing cyber-physical systems via decision support systems based on AI. Rapid sensing is crucial for monitoring systems in the farm-to-fork continuum. Polymer brushes are poised to play a key role in development of advanced interfacial control systems in smart sensor systems, opening new doors toward real time monitoring.