Three-dimensional biomimetic biosensors for food safety applications are presented. The sensors mimic the porous media of fresh produce and can detect the presence of pathogens in low concentration, monitor their internalization, and also determine potential formation of biofilm. The sensors use capacitive/impedance measurement for detection and have 3-dimensional structures allowing microorganisms to occupy the space between electrodes and the substrate. Interdigitated sensors with suspended electrodes and a parallel-plate sensor are studied using finite element analysis, and their performance is compared to that of a 2-imensional planar sensor. The simulation results show that under similar circumstances, all 3D sensors provide better sensitivities for detection of microorganisms and biofilm formation compared to the 2D sensor. 3D interdigitated and parallel-plate sensors display 16% and 30% higher sensitivity in detection of microorganisms, and 44% and 48% higher sensitivity for detection of biofilm formation, respectively. Furthermore, a biomimetic device with stack of electrodes is presented that can monitor the internalization of pathogens in real time. The device forms layers of multiple sensors resembling the actual fresh produce and can track the penetration of microorganisms inside the device. This novel structure allows us to understand how long it takes for microorganisms to penetrate in a produce and how environmental parameters such as temperature variation or the presence of nutrients or sanitizers affect their behavior, providing invaluable data to improve food safety and optimize the sanitization processes.

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