Base-Stacking-Driven Catalytic Hairpin Assembly: A
Nucleic Acid Amplification Reaction Using Electrode Interface as a
“Booster” for SARS-CoV‑2 Point-of-Care Testing
posted on 2023-10-11, 19:03authored byGuanyu Chen, Ning Yang, Lilan Xu, Shi Lu, Zhuhua Chen, Fang Wu, Jinghua Chen, Xi Zhang
Electrochemical
DNA (E-DNA) biosensors based on interface-mediated
hybridization reactions are promising for point-of-care testing (POCT).
However, the low efficiency of target recycle amplification and the
steric hindrance at the electrode interface limit their sensing performance.
Herein, we propose a base-stacking-driven catalytic hairpin assembly
(BDCHA), a nucleic acid amplification reaction strategy, for POCT.
The introduction of the base-stacking effect in this strategy increases
the thermodynamic stability of the product, thereby effectively improving
the recycling efficiency. Also, it enables the interface-mediated
hybridization to maintain stability with even fewer bases in the reaction-binding
domain, hence minimizing DNA secondary structure formation or intertwining
at the electrode surface and ameliorating the steric hindrance limitation.
The introduced base-stacking effect makes the electrode serve as a
“booster” by integrating the advantages of homogeneous
and heterogeneous reactions, giving BDCHA an increased reaction rate
of about 20-fold, compared to the conventional catalytic hairpin assembly.
As a proof of concept, our BDCHA was applied in constructing a portable
E-DNA biosensor for the detection of a SARS-CoV-2 N gene sequence
fragment. A simple 30 min one-pot incubation is required, and the
results can be readily read on a smartphone, making it portable and
user-friendly for POCT.