The detection and identification of nanoscale molecules are crucial, but traditional technology comes with a high cost and requires skilled operators. Solid-state nanopores are new powerful tools for discerning the three-dimensional shape and size of molecules, enabling the translation of molecular structural information into electric signals. Here, DNA molecules with different shapes were designed to explore the effects of electroosmotic forces (EOF), electrophoretic forces (EPF), and volume exclusion on electric signals within solid-state nanopores. Our results revealed that the electroosmotic force was the main driving force for single-stranded DNA (ssDNA), whereas double-stranded DNA (dsDNA) was primarily dominated by electrophoretic forces in nanopores. Moreover, dsDNA caused greater amplitude signals and moved faster through the nanopore due to its larger diameter and carrying more charges. Furthermore, at the same charge level and amount of bases, circular dsDNA exhibited a tighter structure compared to brush DNA, resulting in a shorter length. Consequently, circular dsDNA caused higher current-blocking amplitudes and faster passage speeds. The characterization approach based on nanopores allows researchers to get molecular information about size and shape in real time. These findings suggest that nanopore detection has the potential to streamline nanoscale characterization and analysis, potentially reducing both the cost and complexity.

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DNA 构象对固态纳米孔检测信号的影响

纳米级分子的检测和识别至关重要，但传统技术成本高昂，并且需要熟练的操作人员。固态纳米孔是识别分子三维形状和大小的新的强大工具，能够将分子结构信息转化为电信号。在这里，设计了不同形状的 DNA 分子来探索电渗力 (EOF)、电泳力 (EPF) 和体积排斥对固态纳米孔内电信号的影响。我们的结果表明，电渗力是单链DNA（ssDNA）的主要驱动力，而双链DNA（dsDNA）主要由纳米孔中的电泳力主导。此外，由于双链DNA直径较大且携带更多电荷，因此它会产生更大幅度的信号，并且在纳米孔中移动得更快。此外，在相同的电荷水平和碱基数量下，环状双链DNA与刷状DNA相比表现出更紧密的结构，从而导致长度更短。因此，环状双链 DNA 导致更高的电流阻断幅度和更快的通过速度。基于纳米孔的表征方法使研究人员能够实时获取有关尺寸和形状的分子信息。这些发现表明纳米孔检测有可能简化纳米级表征和分析，从而降低成本和复杂性。