Electrochemical sensor for a photoassisted heterogeneous Fenton self-oxidation signal amplification strategy

Traditional electrochemical immunosensors have stagnated due to the lack of signal tags and single signal amplification strategies. In this work, we propose a new signal amplification strategy, a photoassisted heterogeneous Fenton self-oxidation reaction, for the detection of prostate-specific antigen (PSA). A prepared ferric tetroxide (Fe3O4)@Carbon(C)@Glucose oxidase (GOD) heterogeneous Fenton electrochemical sensor is first immersed in a solution containing glucose, persulfate (S2O82-) and tannic acid (TA), and then it is irradiated with ultraviolet light at 365 nm. Utilizing a coupling reaction, S2O82- promotes the use of ultraviolet light by Fe3O4@C-COOH@GOD to generate more (OH)-O-center dot radicals; furthermore, the coordination of tannic acid to Fe2+ promotes the oxidation of Fe2+ in Fe3O4 to Fe3+ by (OH)-O-center dot. This achieves a signal amplification of 3 times the value of the original system. More importantly, the Fenton reagent undergoes a self-oxidation reaction without the need to add a signal tag. The proposed immunosensor uses a new signal amplification strategy that can be used for detecting tumor markers. Additionally, due to the self-oxidation of the Fenton reagent and the C coating, the problem of signal tag leakage is effectively solved. The electrochemical immunosensor detects different concentrations of PSA and exhibits excellent analytical performance, with a detection limit of 0.17 pg/mL and a detection range of 0.5 pg/mL to 40 ng/mL. The prepared immunosensor provides a feasible method for the detection of cancer tumor markers.