Reversible Redox Activity by Ion-pH Dually Modulated Duplex Formation of i-Motif DNA with Complementary G-DNA.

Soyoung Chang,Hojae Bae,Shirin Oskui,Tugba Kilic,Seon Kim,Chang Lee,Sung Jung,Su Shin,Huseyin Avci

doi:10.3390/nano8040226

Abstract

The unique biological features of supramolecular DNA have led to an increasing interest in biomedical applications such as biosensors. We have developed an i-motif and G-rich DNA conjugated single-walled carbon nanotube hybrid materials, which shows reversible conformational switching upon external stimuli such as pH (5 and 8) and presence of ions (Li+ and K+). We observed reversible electrochemical redox activity upon external stimuli in a quick and robust manner. Given the ease and the robustness of this method, we believe that pH- and ion-driven reversible DNA structure transformations will be utilized for future applications for developing novel biosensors.

Highlights

In recent years, DNA has received significant attention due to the advances in structural DNA nanotechnology that have extended its use for development of dynamic and stimuli-responsive nanomaterials in the form of DNA origami, nanomachines, or nanomotors [1,2,3]
We demonstrate a reversible redox activity by dually modulated duplex formation of i-motif DNA (i-DNA) with complementary G-quadruplex
Four bands in the radial breathing mode (RBM) frequency region of the Raman spectra (150–300 cm−1)—which is known to shift upon modification of i-DNA, G-quadruplex, and i-DNA + G-quadruplex complex [20]—were observed (Figure 1B)

Summary

Introduction

DNA has received significant attention due to the advances in structural DNA nanotechnology that have extended its use for development of dynamic and stimuli-responsive nanomaterials in the form of DNA origami, nanomachines, or nanomotors [1,2,3]. Two- or three-dimensional DNA supramolecular structures [4] can demonstrate reversible conformational switching behavior upon external stimuli such as pH [5], interactions with small molecules [6] and other DNA strands [7], light [8], electricity [9], and temperature [10]. Due to the cation core located at the center, this structure can interact with negatively charged phosphate backbones and remain neutral in charge [14]. These conformational changes may result in unusual structures demonstrating certain advantages, high sensitivity to chemical stimuli such as pH and ions [15]. Sci., 10 (2015) 3897–3913) [16]

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Results

Conclusion