Probing the Conformational States of a pH-Sensitive DNA Origami Zipper via Label-Free Electrochemical Methods

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

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2021-06-29

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en

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7801–7809

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Langmuir, Volume 37, issue 25

Abstract

DNA origami structures represent an exciting class of materials for use in a wide range of biotechnological applications. This study reports the design, production, and characterization of a DNA origami “zipper” structure, which contains nine pH-responsive DNA locks. Each lock consists of two parts that are attached to the zipper’s opposite arms: a DNA hairpin and a single-stranded DNA that are able to form a DNA triplex through Hoogsteen base pairing. The sequences of the locks were selected in a way that the zipper adopted a closed configuration at pH 6.5 and an open state at pH 8.0 (transition pKa7.6). By adding thiol groups, it was possible to immobilize the zipper structure onto gold surfaces. The immobilization process was characterized electrochemically to confirm successful adsorption of the zipper. The open and closed states were then probed using differential pulse voltammetry and electrochemical impedance spectroscopy with solution-based redox agents. It was found that after immobilization, the open or closed state of the zipper in different pH regimes could be determined by electrochemical interrogation. These findings pave the way for development of DNA origami-based pH monitoring and other pH-responsive sensing and release strategies for zipper-functionalized gold surfaces.

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Funding Information: Financial support from EPSRC DTP (grant EP/R513349/1), the Emil Aaltonen Foundation, the Sigrid Jusélius Foundation, the Jane and Aatos Erkko Foundation, and the Vilho, Yrjö and Kalle Väisälä Foundation of the Finnish Academy of Science and Letters is gratefully acknowledged. This work was carried out under the Academy of Finland Centers of Excellence Programme (2014–2019). We acknowledge the provision of facilities and technical support by Aalto University Bioeconomy Facilities and OtaNano—Nanomicroscopy Center (Aalto-NMC) and Micronova Nanofabrication Center. Publisher Copyright: © 2021 The Authors. Published by American Chemical Society

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Citation

Williamson, P, Ijäs, H, Shen, B, Corrigan, D K & Linko, V 2021, ' Probing the Conformational States of a pH-Sensitive DNA Origami Zipper via Label-Free Electrochemical Methods ', Langmuir, vol. 37, no. 25, pp. 7801–7809 . https://doi.org/10.1021/acs.langmuir.1c01110