Crowding Effects during DNA Translocation in Nanopipettes

Fuente: arXiv
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Main Authors: Al-Waqfi, Rand A., Khan, Cengiz, Irving, Oliver J., Matthews, Lauren, Albrecht, Tim
Format: Preprint
Published: 2025
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author Al-Waqfi, Rand A.
Khan, Cengiz
Irving, Oliver J.
Matthews, Lauren
Albrecht, Tim
author_facet Al-Waqfi, Rand A.
Khan, Cengiz
Irving, Oliver J.
Matthews, Lauren
Albrecht, Tim
contents Quartz nanopipettes are an important emerging class of electric single-molecule sensors for DNA, proteins, their complexes as well as other biomolecular targets. However, in comparison to other resistive pulse sensors, nanopipettes constitute a highly asymmetric environment and the transport of ions and biopolymers can become strongly direction-dependent. For double-stranded DNA, this can include the characteristic translocation time and its tertiary structure, but as we show here, nanoconfinement can not only lead to unexplored features in the transport characteristics of the sensor, but also unlock new capabilities for biophysical and bioanalytical studies at the single-molecule level. To this end, we show how the accummulation of DNA inside the nanochannel leads to crowding effects, and in some cases reversible blocking of DNA entry, and provide a detailed analysis based on a range of different DNA samples and experimental conditions. Moreover, using biotin-functionalised DNA and streptavidin-modified gold nanoparticles as target, we demonstrate in a proof-of-concept study how the crowding effect, and the resulting increased residence time in nanochannel, can be exploited in a new analytical paradigm, involving DNA injection into the nanochannel, incubation with the nanoparticle target and analysis of the complex by reverse translocation. We thereby integrate elements of sample processing and detection into the nanopipette, as an important conceptual advance, and make a case for the wider applicability of this device concept.
format Preprint
id arxiv_https___arxiv_org_abs_2501_14347
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Crowding Effects during DNA Translocation in Nanopipettes
Al-Waqfi, Rand A.
Khan, Cengiz
Irving, Oliver J.
Matthews, Lauren
Albrecht, Tim
Mesoscale and Nanoscale Physics
Applied Physics
Quartz nanopipettes are an important emerging class of electric single-molecule sensors for DNA, proteins, their complexes as well as other biomolecular targets. However, in comparison to other resistive pulse sensors, nanopipettes constitute a highly asymmetric environment and the transport of ions and biopolymers can become strongly direction-dependent. For double-stranded DNA, this can include the characteristic translocation time and its tertiary structure, but as we show here, nanoconfinement can not only lead to unexplored features in the transport characteristics of the sensor, but also unlock new capabilities for biophysical and bioanalytical studies at the single-molecule level. To this end, we show how the accummulation of DNA inside the nanochannel leads to crowding effects, and in some cases reversible blocking of DNA entry, and provide a detailed analysis based on a range of different DNA samples and experimental conditions. Moreover, using biotin-functionalised DNA and streptavidin-modified gold nanoparticles as target, we demonstrate in a proof-of-concept study how the crowding effect, and the resulting increased residence time in nanochannel, can be exploited in a new analytical paradigm, involving DNA injection into the nanochannel, incubation with the nanoparticle target and analysis of the complex by reverse translocation. We thereby integrate elements of sample processing and detection into the nanopipette, as an important conceptual advance, and make a case for the wider applicability of this device concept.
title Crowding Effects during DNA Translocation in Nanopipettes
topic Mesoscale and Nanoscale Physics
Applied Physics
url https://arxiv.org/abs/2501.14347