Ultrasensitive biosensing platform via self-catalytic-induced luminescence amplification and bifunctional biopeptides for immunoassay.

The output signal of the sensor is closely correlated with its detection sensitivity, while the selection of luminescent materials and the presence of interfering substances in the detection medium can both affect the output signal. In this study, a bifunctional peptide (HWRGWVDEDKDKDKC) with antibody targeted fixation and interface anti-adsorption properties was designed by integrating recognition (HWRGWV), charge neutralization (DE), antifouling (DKDKDKDK) and anchoring (C) fragments, which endowed the constructed biosensing interface with high target capture efficiency and good antifouling ability. At the same time, AuAgTb-MOF with multiple synergistic amplification effects was developed as luminophore. Concretely, the antenna effect of 3,5-dicarboxyphenylboronic acid to Tb, the catalysis of Ag NPs for SO and the conductivity of Au NPs significantly prompted the luminescence of AuAgTb-MOF. The design of intramolecular self-enhanced AuAgTb-MOF not only reduced energy transfer losses, but also simplified the construction of the biosensing platform. On this basic, the constructed biosensor had a wide detection range of 10 to 10 U/mL and a low limit of detection of 3.38 × 10 U/mL (IUPAC standard), realizing the sensitive and precise detection for pancreatic cancer markers, thus providing a positive reference for the clinical diagnosis of pancreatic cancer.