Fig. 1

a Schematic illustration of IL-3 identification on an anti-IL-3-modified capacitance sensing surface. APTMS-modified zeolite-iron was used to attach the capture antibody and then interacted with IL-3. PEG-COOH was used as the blocking agent. b Morphological analysis of the capacitance sensing surface by high-power microscopy. c Morphological analysis of zeolite-iron by FESEM. Nanomaterials were formed with a uniform distribution and in the longitudinal dimension. d EDX analysis. The presence of the main elements Si, Al, Fe, and O was found. The figure inset was obtained by FESEM with low magnification