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 pKa 7.6). 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.
Highlights
Electrochemical DNA biosensing may enable low cost, reliable, and specific detection of various known and emerging biomarkers associated with human disease
We have employed an unlabeled switchable/dynamic DNA origami zipper device (Figure 1), which we aim to observe via electrochemical methods of differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS)
The active, pHsensitive zippers were designed with nine copies of 18-nt long Hoogsteen-type DNA triplexes with a %TAT = 66.7 for an approximate pKa of 7.6.32,47 For the open controls, the ssDNA counterparts of the triplexes were substituted with scrambled DNA sequences that cannot take part in triplex formation
Summary
Electrochemical DNA biosensing may enable low cost, reliable, and specific detection of various known and emerging biomarkers associated with human disease. Introduction of ordered monolayers of single stranded DNA to an electrode by self-assembly techniques provides a method of capturing and detecting complementary target sequences of interest from solution. Applications of this sensing principle are far reaching, including the detection of bacterial nucleic acids associated with AMR,[1−3] circulating tumor DNA sequences,[4,5] and single nucleotide polymorphisms.[6,7] Despite much promise in laboratories worldwide, translation into clinical or field settings has proved challenging. Many sensors are still limited by the success rate of self-assembly methods, their inherent variability in establishing an appropriate baseline signal, and corresponding signal drift
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
