Nanofluidic trapping and enhanced Raman detection of single biomolecules in plasmonic bowl-shaped nanopore

TL;DR

This paper introduces a novel plasmonic bowl-shaped nanopore with hydrogel for nanofluidic manipulation and stable Raman detection of single DNA molecules, advancing label-free single-molecule protein sequencing.

Contribution

It presents a new bowl-shaped plasmonic nanopore design with hydrogel that enables near-field nanofluidic control and enhanced Raman detection of single biomolecules.

Findings

DNA was linearized and trapped for tens of seconds in the nanopore

Near-field confinement enabled stable Raman detection of DNA

The approach could facilitate label-free single-molecule protein sequencing

Abstract

Solid-state nanopores are emerging platforms for single-molecule protein sequencing due to their tolerance to hash physiology environment and compatibility with different electrical and optical detection methods. However, they suffer from poor molecular manipulations that were twisted with and thus limited by the detection methods. Here, we report a bowl-shaped plasmonic gold nanopore on silicon nitride with hydrogel to demonstrate near-field nanofluidic manipulation of DNA translocation for plasmon-enhanced Raman spectroscopic detection. The hydrogel linearized the DNA, and the linear DNA was trapped in the nanopore for tens of seconds due assumably to bipolar effect of the nanopore that generate electroosmotic sheath flow and bipolar surface charge distribution. Their combination led to a near-field confinement of the DNA in the nanopore hot spot to allow stable Raman detection. We envision that a combination of Raman spectroscopy with the bowl-shaped nanopores can succeed in single-molecule protein sequencing in a label-free way