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 (Fe 3 O 4 )@Carbon(C)@Glucose oxidase (GOD) heterogeneous Fenton electrochemical sensor is first immersed in a solution containing glucose, persulfate (S 2 O 8 2− ) and tannic acid (TA), and then it is irradiated with ultraviolet light at 365 nm. Utilizing a coupling reaction, S 2 O 8 2- promotes the use of ultraviolet light by Fe 3 O 4 @C−COOH@GOD to generate more OH radicals; furthermore, the coordination of tannic acid to Fe 2+ promotes the oxidation of Fe 2+ in Fe 3 O 4 to Fe 3+ by OH. 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.