PDF(Pubmed)
Abstract：
We report the generation of ∼8 nm dual in-plane pores fabricated in a thermoplastic via nanoimprint lithography (NIL). These pores were connected in series with nanochannels, one of which served as a flight tube to allow the identification of single molecules based on their molecular-dependent apparent mobilities (i.e., dual in-plane nanopore sensor). Two different thermoplastics were investigated including poly(methyl methacrylate), PMMA, and cyclic olefin polymer, COP, as the substrate for the sensor both of which were sealed using a low glass transition cover plate (cyclic olefin co-polymer, COC) that could be thermally fusion bonded to the PMMA or COP substrate at a temperature minimizing nanostructure deformation. Unique to these dual in-plane nanopore sensors was two pores flanking each side of the nanometer flight tube (50 × 50 nm, width × depth) that was 10 μm in length. The utility of this dual in-plane nanopore sensor was evaluated to not only detect, but also identify single ribonucleotide monophosphates (rNMPs) by using the travel time (time-of-flight, ToF), the resistive pulse event amplitude, and the dwell time. In spite of the relatively large size of these in-plane pores (∼8 nm effective diameter), we could detect via resistive pulse sensing (RPS) single rNMP molecules at a mass load of 3.9 fg, which was ascribed to the unique structural features of the nanofluidic network and the use of a thermoplastic with low relative dielectric constants, which resulted in a low RMS noise level in the open pore current. Our data indicated that the identification accuracy of individual rNMPs was high, which was ascribed to an improved chromatographic contribution to the nano-electrophoresis apparent mobility. With the ToF data only, the identification accuracy was 98.3%. However, when incorporating the resistive pulse sensing event amplitude and dwell time in conjunction with the ToF and analyzed via principal component analysis (PCA), the identification accuracy reached 100%. These findings pave the way for the realization of a novel chip-based single-molecule RNA sequencing technology.
摘要：
我们报告了通过纳米压印光刻（NIL）在热塑性塑料中制造的〜8nm双平面孔的生成。这些孔与纳米通道串联连接，其中之一用作飞行管，以允许基于其分子依赖性表观迁移率来识别单分子(即，双面内纳米孔传感器)。研究了两种不同的热塑性塑料，包括聚（甲基丙烯酸甲酯），PMMA,和环状烯烃聚合物，COP,作为传感器的基板，两者都使用低玻璃化转变盖板（环烯烃共聚物，COC）可以在使纳米结构变形最小化的温度下热熔合结合到PMMA或COP衬底。这些双平面内纳米孔传感器的独特之处在于纳米飞行管每侧的两个孔（50×50nm，宽度×深度），长度为10μm。评估了这种双面内纳米孔传感器的实用性，不仅可以检测，而且还通过使用旅行时间(飞行时间，ToF),电阻脉冲事件振幅，和停留时间。尽管这些面内孔的尺寸相对较大(~8纳米有效直径)，我们可以通过电阻脉冲传感（RPS）在3.9fg的质量负荷下检测单个rNMP分子，这归因于纳米流体网络的独特结构特征和使用具有低相对介电常数的热塑性塑料，这导致开孔电流中的低RMS噪声水平。我们的数据表明，个体rNMP的识别准确性很高，这归因于对纳米电泳表观迁移率的改进的色谱贡献。只有ToF数据，识别准确率为98.3%。然而,当将电阻脉冲感测事件幅度和停留时间与ToF结合并通过主成分分析(PCA)进行分析时,识别准确率达到100%。这些发现为实现新型基于芯片的单分子RNA测序技术铺平了道路。
