A Signal-Amplified Electrochemical Immunosensor Based on Prussian Blue and Pt Hollow Nanospheres as Matrix

Through electrodepositing Prussian blue (PB) and chitosan (CS), then casting Pt hollow nanospheres (HN-Pt) and assembling CA19-9 antibody on the electrode surface, an immunosensor was achieved. A new signal amplification strategy based on PB and HN-Pt toward the electrocatalytic reduction of H2O2 was employed when performing the determination. The resulting immunosensor showed a high sensitivity, broad linear response to carbohydrate antigen 19-9 (CA19-9) in two ranges from 0.5 to 30 and 30 to 240 U mL(-1) with a low detection limit of 0.13 U mL(-1) (S/N = 3). Moreover, it displayed good reproducibility and stability, and would be potentially attractive for clinical immunoassay of CA19-9.