Fig. 4

a The whole detection device. The syringe pump was used to inject solution into the CASPE-MFD, and the electrochemical workstation was used to detect the electrochemical signals. b The CASPE-MFD used to detect PSA. Immunomagnetic bead-conjugated anti-PSA antibody was injected with solutions through inlet, and a magnet was used to capture the magnetic beads. c Schematic of the CASPE-MFD in detection of PSA antigen. Immunomagnetic bead-conjugated anti-PSA antibody was immobilized on the working electrode using a magnet. PSA antigen was injected into the CASPE-MFD and conjugated with the anti-PSA antibody. HRP-modified anti-PSA antibody was then conjugated with PSA antigen. Chronoamperometry was used to detect the electrochemical signals that hydroquinone and hydrogen peroxide produced