Nanochannels-based self-correction electrochemical detection of mucin 1 with in-situ generated phosphomolybdic acid

Accurate detection of cancer biomarkers like mucin 1 (MUC-1) is significantly important for diagnosis and prognosis of tumor. Herein, a self-correction electrochemical immunoassay for MUC-1 detection was developed based on bioinspired nanochannels and electrochemistry of molybdophosphate. MUC-1 can be captured in the bioinspired polymer nanochannels via the formation of immunocomplex. Then, diffusion of MoO 4 2− in the nanochannels would be sterically hindered and the in-situ generation of phosphomolybdic acid onto the electrode surface which was modified with phosphate chitosan hydrogel, would be influenced. Therefore, the two well-defined redox peaks of phosphomolybdic acid can be applied to the detection of the antigen. To improve detection sensitivity, the phosphate chitosan was incorporated with carbon nanotubes. Moreover, the occurrence in nanochannels was amplified by hybridization chain reaction, which enhanced the hindrance for transport of MoO 4 2− by increasing steric effect, electrostatic repulsion as well as anchoring sites. Under optimized conditions, currents of the both anodic peaks on square wave voltametric voltammograms decreased linearly with the logarithm of the concentration of MUC-1 ranging from 10 fg∙mL −1 to 100 ng∙mL −1 with a detection limit of 6.0 fg∙mL −1 . And thus, the detection results can be self-corrected by the results acquired from the two peaks, which had valuable implications for the reliable MUC-1 detection in disease diagnosis and therapy application.