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Nano-corrugated Nanochannels for In Situ Tracking of Single-Nanoparticle Translocation Dynamics.
ACS Sensors ( IF 8.2 ) Pub Date : 2020-07-31 , DOI: 10.1021/acssensors.0c00845 Makusu Tsutsui 1 , Kazumichi Yokota 2 , Yuhui He 3 , Takashi Washio 1 , Tomoji Kawai 1
ACS Sensors ( IF 8.2 ) Pub Date : 2020-07-31 , DOI: 10.1021/acssensors.0c00845 Makusu Tsutsui 1 , Kazumichi Yokota 2 , Yuhui He 3 , Takashi Washio 1 , Tomoji Kawai 1
Affiliation
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Dynamic motions of materials in liquid present a wealth of information concerning their physical properties. While fluorescence microscopy has been widely utilized for single-particle observations, the method cannot be used for characterizing fast motions of nanoscale objects due to the limited spatiotemporal resolution. Here, we report on a nanostructure strategy for nanoscale tracking of single nanoparticles. We fabricated a straight conduit in a SiO2 layer on a Si wafer with lithographically defined 30 nm-sized protrusions formed on the side walls. We performed resistive pulse measurements at a 1 MHz sampling rate wherein we found n-stepped current traces signifying n number of nanoparticles moving concurrently inside the nanochannel. Ensemble average of the ionic current signals revealed a peculiar feature reflecting the slightly stronger ion blockage at the nanoconstrictions between the protrusions, thereby proving the ability of nano-corrugation as physical gates to signify the precise positions of objects inside the nanofluidic channel. This in situ tracking approach elucidated steady-state motions of the nanoparticles moving at a constant speed under the counter-balanced electrophoretic and viscous drag forces, which also allowed estimations of their surface charge densities. The present method can be utilized as a speedometer for nanoscale objects of virtually any size as long as they are able to be put through the sensing zones with potential applications for single-molecule time-of-flight mass spectrometry.
中文翻译：
用于单纳米颗粒移位动力学原位追踪的纳米波纹纳米通道。
材料在液体中的动态运动提供了大量有关其物理性质的信息。尽管荧光显微镜已被广泛用于单粒子观察，但由于时空分辨率的限制，该方法不能用于表征纳米尺度物体的快速运动。在这里，我们报告了单个纳米颗粒的纳米级跟踪的纳米结构策略。我们在硅晶片上的SiO 2层中制造了一条直管，并在侧壁上形成了光刻定义的30 nm尺寸的凸起。我们以1 MHz的采样率进行了电阻脉冲测量，发现n阶跃的电流迹线表示n同时在纳米通道内移动的纳米颗粒的数量。离子电流信号的整体平均值显示出一个独特的特征，反映了突起之间纳米收缩处的离子阻塞稍强，从而证明了纳米波纹作为物理门的能力，可以表示物体在纳米流体通道内的精确位置。这种原位跟踪方法阐明了在平衡的电泳和粘性拖曳力下以恒定速度运动的纳米颗粒的稳态运动，这也允许估算其表面电荷密度。
更新日期：2020-08-28
中文翻译：
用于单纳米颗粒移位动力学原位追踪的纳米波纹纳米通道。
材料在液体中的动态运动提供了大量有关其物理性质的信息。尽管荧光显微镜已被广泛用于单粒子观察，但由于时空分辨率的限制，该方法不能用于表征纳米尺度物体的快速运动。在这里，我们报告了单个纳米颗粒的纳米级跟踪的纳米结构策略。我们在硅晶片上的SiO 2层中制造了一条直管，并在侧壁上形成了光刻定义的30 nm尺寸的凸起。我们以1 MHz的采样率进行了电阻脉冲测量，发现n阶跃的电流迹线表示n同时在纳米通道内移动的纳米颗粒的数量。离子电流信号的整体平均值显示出一个独特的特征，反映了突起之间纳米收缩处的离子阻塞稍强，从而证明了纳米波纹作为物理门的能力，可以表示物体在纳米流体通道内的精确位置。这种原位跟踪方法阐明了在平衡的电泳和粘性拖曳力下以恒定速度运动的纳米颗粒的稳态运动，这也允许估算其表面电荷密度。
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