Fig. 1.

Schematic illustration of the immunosensor measurement procedure. Firstly, 3D SM is fabricated on the Transwell membrane, then MB·Abs are loaded in the lower compartment. Secreted cytokines, under the chemical and electrical effect, are captured by the MB·Abs. Detection step is followed by the addition of a biotinylated antibody and SAV-pHRP. Finally, MB·Abs are resuspended in enzymatic buffer and captured on the surface of the SPCEs. After addition of the corresponding substrate, EC signal is obtained. The intensity of the current is directly related with the concentration of secreted cytokines.