Ultrasensitive dual-mode detection of amyloid β oligomer via Au NRs modulated photoelectrochemical/electrochemiluminescent response from HOFs/g-C3N4

Abstract

In this work, a heterojunction composite of HOFs/g-C3N4 was synthesized using solution-plasticized self-assembly of g-C3N4 nanosheet on hydrogen-bonded organic frameworks (HOFs). HOFs/g-C3N4 was then used as a substrate material to construct a novel photoelectrochemical/electrochemiluminescent (PEC/ECL) biosensor for the detection of amyloid β oligomer (Aβo). HOFs/g-C3N4 composites were first drop-coated on the electrode surface. Subsequently, the Aβ aptamer was modified on the electrode surface via amide bonding. The target Aβo and the gold nanorods (Au NRs)-labeled Aβ recognition peptide (Au NRs-KLVFF) were simultaneously dropped onto the electrode surface, thus a “sandwich” dual-mode biosensor was constructed. In the PEC detection of the Aβo, the surface plasmon resonance effect of Au NRs enhanced the visible absorption of HOF/g-C3N4, and the sensor exhibited a "signal-on" photocurrent signal. Meanwhile, the ECL emission spectrum of HOF/g-C3N4 in ECL mode overlaps with the ultraviolet-visible (UV) absorption of Au NRs, and the sensor signal showed a “signal-off” ECL response. Under the optimal conditions experiments, the constructed dual-mode biosensor showed a wide detection range and low detection limit for Aβo. The proposed dual-mode detection method has a detection range of 10 fM to 10 nM with a detection limit of 5.97 fM for PEC detection and a detection range of 0.1 pM to 1.0 μM with a detection limit of 0.051 pM for ECL detection respectively. Additionally, the detection method achieved satisfactory results in the analysis of real samples. Dual-mode sensing platform provides a new strategy for HOFs application in PEC/ECL assay and sensitive detection of AβO.