Signal-off photoelectrochemical biosensing platform based on hybridization chain-doped manganese porphyrin quenching on CdSe signal coupling with cyclic amplification for thrombin detection

Abstract

A novel signal-off photoelectrochemical (PEC) biosensing platform based on hybridization chain-doped manganese porphyrin quenching on PEC signal of CdSe quantum dots (QDs) coupling with cyclic amplification was developed for thrombin detection. Target thrombin firstly induced DNA enzyme-aided cyclic amplification reaction and produced abundant DNA I. Then DNA I hybridized with capture DNA on the TiO 2 /CdSe QDs modified electrode to form DNA bridge, which triggered a linear chain hybridization reaction with S4 and S5. Numerous manganese porphyrin (MnPP) were doped in the long double-stranded DNA chain, which hindered electron transfer and resulted in obvious decrease of QDs PEC signal, achieving a sensitive detection of thrombin. This PEC biosensor exhibits excellent performance with a wide linear range from 1.0 f. to 100.0 nM and detection limit of 0.331 fM, and the recovery value ranged from 95.5% to 103.5%. The results suggest that this PEC biosensor has high sensitivity and precision, showing great application prospect in microbiological analysis of biomolecules and clinical medicine. • A novel signal-off PEC biosensor based on DNA linear chain-doped MnPP quenching to QDs was reported. • CdSe QDs and TiO 2 complex displayed strong PEC signal. • A large amount of manganese porphyrin doped in linear DNA chain greatly amplified PEC signal change. • DNA S1 and S2 specifically bind to thrombin to form the pliers structure with high selectivity.