Low-Cost, High-Sensitivity Paper-Based Bacteria Impedance Sensor Based on Vertical Flow Assay

This study proposes a low-cost, portable paper-fluidic vertical flow assay bacterium counter with high accuracy. We designed sensors low fabrication costs based on e-beam evaporation and three-dimensional printing the impedance measurement principle. Interdigitated (IDT) electrodes were coated filter membrane by shadow mask. could print wafer-scale frames melting temperature three-dimensional-printing materials for confining liquid bacterial samples within IDT sensing region. novel technique significantly reduced chip’s cost to less than 1% of that silicon-based chips. Two equivalent circuit models proposed different concentration ranges analyze principle paper-based sensors. an improved model Randles concentrations considering leaky double-layer capacitor effect spherical diffusion from nano-structural gold-coated membrane. The phenomenon in which charge transfer resistance, Rct, declines at was found explained pearl chain effect. cause false-negative concentrations. modeled as R C, connected parallel low-concentration model. When users properly applied both analyses, this sensor quantitatively measure cell 400 M per milliliter superior linearity.