Electrochemiluminescence Peptide-Based Biosensor with Hetero-Nanostructures as Coreaction Accelerator for the Ultrasensitive Determination of Tryptase

In this work, a luminol-centric biosensor was constructed for the ultrasensitive detection of tryptase (TPS) combining dissolved O-2 as the endogenous coreactant and AuAg-Pt heteronanostructures (AAPHNs) as coreaction accelerator. Dissolved O-2 could rapidly generate superoxide anion radical (O-2(center dot-)) with the catalysis of AAPHNs to in situ react with luminol anion radical (L.-) to generate excited-state species 3-amino phthalate (AP(2-)*) for emitting ECL signal, resulting in a remarkable single on state. In order to further improve the sensitivity of the sensor, we employed self-assembled DNA nanotubes (DNANTs) as a carrier to immobilize the luminophore of doxorubicin-luminol (Dox-Lu) complex. In this assay system, target tryptase could directly induce the cleavage of vasoactive intestinal peptide (VIP), which caused the ECL probe DNANTs-Dox-Lu releasing from the electrode surface to obtain a significant signal off state. By changing the signal from on to off, the proposed ECL peptide-based biosensor for TPS detection achieved a dynamic concentration range (2.5 pg/mL-200 ng/mL) with an extremely low detection limit of 0.81 pg/mt. This work presented a new signal amplification method for the construction of the sensor based on the luminol-dissolved O-2 ECL system.