Translocation of Specific DNA Nanocarrier through an Ultrasmall Nanopipette: Toward Single-Protein-Molecule Detection with Superior Signal-to-Noise Ratio

The use of functional DNA nanostructures as carriers to ship proteins through solid-state nanopores has recently seen substantial growth in single-protein-molecule detection (SPMD), driven by the potential of this methodology and implementations that it may enable. Ultrasmall nanopores have exhibited obvious advantages in spatiotemporal biological detection due to the appropriate nanoconfined spaces and unique properties. Herein, a 6.8 nm DNA tetrahedron (TDN) with a target-specific DNA aptamer (TDN-apt) was engineered to carry the representative target of acetylcholinesterase (AChE) through an ultrasmall nanopipet with a 30 nm orifice, underpinning the advanced SPMD of AChE with good performance in terms of high selectivity, low detection limit (0.1 fM), and especially superior signal-to-noise ratio (SNR). The kinetic interaction between TDN-apt and AChE was studied and the practical applicability of the as-developed SPMD toward real samples was validated using serum samples from patients with Alzheimer's disease. This work not only presented a feasible SPMD solution toward low-abundance proteins in complex samples and but also was envisioned to inspire more interest in the design and implementation of synergized DNA nanostructure-ultrasmall nanopore systems for future SPMD development.

Automated summary

The use of functional DNA nanostructures as carriers to transport proteins through solid-state nanopores has shown significant progress in single-protein-molecule detection. In this study, a 6.8 nm DNA tetrahedron was used as a carrier to successfully detect acetylcholinesterase with high specificity, low detection limit, and superior signal-to-noise ratio through an ultrasmall nanopipet. The practical applicability of this method was validated using serum samples from patients with Alzheimer's disease.