Self-On Aptasensor Based on Interface Oxidation-Induced H₂O₂ Etching Strategy for Ultrasensitive Detection of...

Rhabdomyosarcoma (RMS), a highly malignant tumor that is more common in children, has a high mortality rate. So far, there have been few reports on the early diagnosis of RMS. As an effective biomarker for RMS, the serum level of myoglobin (MyoG) is of significant value for the clinical diagnosis of RMS. In this work, an ultrasensitive electrochemiluminescence (ECL) self-on aptasensor was developed using the interface oxidation-induced H₂O₂ etching strategy for trace detection of MyoG. Specifically, l-tryptophan (l-Trp) and ascorbic acid reacted at a given voltage to produce H₂O₂, which etched the external Ag shell of NaF₄:Eu³⁺@Ag and released the encapsulated NaF₄:Eu³⁺ luminophores. Meanwhile, due to the high interfacial conductivity and catalytic activity of Au@Pt nanoblocks, the ECL emission of NaF₄:Eu³⁺ was enhanced, achieving strong signal self-on. When the MyoG antigen was present, the MyoG aptamer-l-Trp (Apt-l-Trp) was separated from the electrode surface due to the specific binding between the MyoG antigen and Apt. Therefore, the generation of H₂O₂ was interrupted, thus terminating the etching of the Ag shell and leading to signal off. Based on this, the proposed ECL aptasensor achieved sensitive detection of MyoG in a wide concentration range of 1 pg/mL to 10 μg/mL, with a detection limit of 296.15 fg/mL (S/N = 3). The designed interface oxidation-induced H₂O₂ etching strategy extends the construction means of self-on sensors and provides an effective reference for the diagnosis of early RMS.