Detection of Pathogens and Formation of Biofilms Using a Three-Dimensional Biomimetic Biosensing Platform

Internalization of pathogens inside pores and channels of fresh produce and formation of polymeric biofilm around their colonies are important phenomena in food safety due to complications they create for removal and inactivation of pathogens. The practical challenges does not allow for monitoring the pathogen-produce interaction in real time and under different ambient conditions. The present work introduces a biomimetic biosensing platform that simulates the actual produce and can detect the presence, growth and internalization of microorganisms and also potential formation of biofilm. The system consists of layers of capacitive electrodes made of polycrystalline silicon which are designed based on a standard foundry process (PolyMUMPs). The electrodes form multiple impedance-based biosensors and can simulate porous medium of the produce surface. As the cells reside on the surface of the top layer or penetrate inside the system, the capacitance value of each electrode pair changes. Monitoring the capacitance change of each biosensor allows us to determine where the microorganisms are and also whether their population is increasing. To demonstrate the applicability of our proposed biosensing system, a comprehensive FEM simulation is performed using ANSYS® APDL. The simulation results show that each pair of electrodes displays a specific pattern of capacitance change when cells reside on the system’s surface, move inside, grow or produce polymeric biofilm, because the electrostatic properties of cells and biofilm polymers are different from those of the solution. Analyzing the capacitance patterns allows us to determine that cells are at which stage of growth or internalization, and how far they have moved inside the system.