Figure 1
From: Immunological assay using a solid-state pore with a low limit of detection
Adapore system. (a) Antibody-modified polystyrene beads are dispersed in a solution. When an antigen is added to the aqueous solution, aggregates of polystyrene beads are formed by the antigen–antibody reaction. (b) Isolated antibody-modified polystyrene beads and aggregates flow from the top to the bottom due to hydrostatic pressure and electrophoresis. The change in the ion current depends on the degree of aggregation of the beads as they pass through the solid-state pore. Large aggregates provide large changes in the ionic current. (c) The solid-state pore module used in the experiment. The black area in the center is the silicon substrate on which the solid-state pore is fabricated. The Ag/AgCl electrodes were fabricated by printing. The cis and trans channels fabricated by PDMS have a crossed spatial arrangement. (d) Only the center part is dug by wet etching to hold the Si3N4 thin film, which is 100-μm square and 50-nm thick. (e) SEM image of a solid-state pore with a diameter of 1.2 μm and a length of 50 nm at a 40° tilt angle. (f) Cross-sectional view of a solid-state pore module in which the hydraulic pressure can be controlled by the amount of liquid in the cis chamber. By adjusting the liquid volume in the cis chamber, L is adjusted to control the hydraulic pressure. (g) 3D schematic of the solid-state pore module. Corresponding to the 2D cross-sectional view shown in Fig. 1f, the cis and trans chambers are shown in red and blue, respectively.
