The invention of DNA nanotechnology has enabled molecular computation as a promising substitute for traditional semiconductors which are limited to two-dimensional architectures and by heating problems resulting from densification. Current studies of logic gates achieved using DNA molecules are predominately focused on two-state operations (AND, OR, etc.); however, realizing tri-state logic (high impedance Z) in DNA computation is understudied. Here we actively fold DNA origami chain-like hinged rods to induce conformational changes that return tri-state logic signals. We use rigid six helix-bundle (6HB) DNA origami to self-assemble a linear trimer chain as a circuit platform with functional single-stranded (ss) DNA near each semi-flexible hinge. The presence or absence of ssDNA enable and input strands allows hybridization to take place at the hinges, activating one fold (0) or two folds (1) from the straight linear geometry (defined as High-Z) of the trimer chain. We design two different tri-state logic gate platforms, buffer and inverter, with corresponding enable/input ssDNA to unambiguously return tri-state signals, characterized by Atomic Force Microscopy (AFM) and/or agarose gel electrophoresis (GEL). Our work on tri-state logic significantly enhances DNA computation beyond the current two-state Boolean logic with both research and industrial applications, including cellular treatments and living matter utilizing the biocompatibility of DNA molecules.

中文翻译：

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通过激活DNA折纸链进行三态逻辑计算

DNA 纳米技术的发明使分子计算成为传统半导体的有前途的替代品，传统半导体仅限于二维结构和致密化产生的加热问题。目前对使用 DNA 分子实现的逻辑门的研究主要集中在两种状态运算（AND、OR等）；然而，在 DNA 计算中实现三态逻辑（高阻抗 Z）尚未得到充分研究。在这里，我们主动折叠 DNA 折纸链状铰接杆，以诱导返回三态逻辑信号的构象变化。我们使用刚性六螺旋束 (6HB) DNA 折纸来自组装线性三聚体链作为电路平台，每个半柔性铰链附近都有功能性单链 (ss) DNA。 ssDNA 使能链和输入链的存在或不存在都允许在铰链处发生杂交，从而激活三聚体链的直线几何形状（定义为高 Z）的一个折叠 (0) 或两个折叠 (1)。我们设计了两种不同的三态逻辑门平台：缓冲器和反相器，具有相应的使能/输入 ssDNA，以明确返回三态信号，其特征在于原子力显微镜 (AFM) 和/或琼脂糖凝胶电泳 (GEL)。我们在三态逻辑方面的工作显着增强了 DNA 计算，超越了当前的两态布尔逻辑，在研究和工业应用中，包括利用 DNA 分子的生物相容性进行细胞治疗和生命物质。