Department of Electrical Engineering, Engineering College, University of Ha'il, Ha'il 55476, Saudi Arabia.
Electrical and Computer Engineering Department, University of California Davis, Davis, CA 95616, USA.
Biomolecules. 2023 Jan 8;13(1):129. doi: 10.3390/biom13010129.
DNA is an attractive material for a range of applications in nanoscience and nanotechnology, and it has recently been demonstrated that the electronic properties of DNA are uniquely sensitive to its sequence and structure, opening new opportunities for the development of electronic DNA biosensors. In this report, we examine the origin of multiple conductance peaks that can occur during single-molecule break-junction (SMBJ)-based conductance measurements on DNA. We demonstrate that these peaks originate from the presence of multiple DNA conformations within the solutions, in particular, double-stranded B-form DNA (dsDNA) and G-quadruplex structures. Using a combination of circular dichroism (CD) spectroscopy, computational approaches, sequence and environmental controls, and single-molecule conductance measurements, we disentangle the conductance information and demonstrate that specific conductance values come from specific conformations of the DNA and that the occurrence of these peaks can be controlled by controlling the local environment. In addition, we demonstrate that conductance measurements are uniquely sensitive to identifying these conformations in solutions and that multiple configurations can be detected in solutions over an extremely large concentration range, opening new possibilities for examining low-probability DNA conformations in solutions.
DNA 是一种在纳米科学和纳米技术中具有广泛应用前景的材料，最近已经证明，DNA 的电子性质对其序列和结构具有独特的敏感性，这为开发电子 DNA 生物传感器开辟了新的机会。在本报告中，我们研究了在基于单分子断键（SMBJ）的电导测量中可能出现的多个电导峰的起源。我们证明，这些峰源自溶液中存在多种 DNA 构象，特别是双链 B 型 DNA（dsDNA）和 G-四链体结构。我们使用圆二色性（CD）光谱、计算方法、序列和环境控制以及单分子电导测量相结合的方法，解卷积电导信息，并证明特定的电导值来自 DNA 的特定构象，并且这些峰的出现可以通过控制局部环境来控制。此外，我们证明电导测量对在溶液中识别这些构象具有独特的敏感性，并且可以在极其大的浓度范围内检测到溶液中的多种构象，为在溶液中检查低概率 DNA 构象开辟了新的可能性。
