Super self-on biosensor based on target molecule-responsive mode and antifouling biopeptides for ultrasensitive...

Target molecule responsive is an effective application mode for self-on sensors, which can improve the detection sensitivity through obvious signal changes. In this study, an ultrasensitive target molecule-responsive electrochemiluminescence (ECL) biosensor with an antifouling function was designed for prostate specific antigen (PSA) monitoring. Concretely, the binding of PSA aptamers and complementary DNA blocked the pores of the aminated SiO₂, thereby effectively encapsulating luminol. Secondly, the stronger specific binding between PSA and its aptamers triggered target molecule responsiveness, leading to the disintegration of blocked dsDNA and the release of luminol. Moreover, Mn-based two-dimensional nanosheets (Mn NSs) were introduced as the substrates, which made the sensing interface present a good load efficiency and electron transfer ability. At the same time, the modified Mn NSs could also serve as co-reaction promoters to catalyze the decomposition of H₂O₂, producing more reactive oxygen species (O₂^•-) for ECL emissions. Thus, the introduction of Mn NSs achieved effective loading and significant signal amplification of released luminol. Importantly, the peptides (CPPPPKDKDKD) with antifouling properties are designed for interface modification, which resisted non-specific adsorption of interfering substances, thus extending the service life of the biosensor. On this basis, the constructed super self-on ECL biosensor exhibited high sensitivity and accuracy for PSA detection in serum, with a low detection limit of 1.58 fg/mL, offering a more effective biosensing platform for clinical diagnosis of prostate cancer.