Department of Mechanical Engineering, Lyle School of Engineering, Southern Methodist University, Dallas, Texas, USA.
Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas, USA.
Electrophoresis. 2020 Apr;41(7-8):630-637. doi: 10.1002/elps.201900336. Epub 2019 Nov 25.
In this work, we present a step-by-step workflow for the fabrication of 2D hexagonal boron nitride (h-BN) nanopores which are then used to sense holo-human serum transferrin (hSTf) protein at pH ∼8 under applied voltages ranging from +100 mV to +800 mV. 2D nanopores are often used for DNA, however, there is a great void in the literature for single-molecule protein sensing and this, to the best of our knowledge, is the first time where h-BN-a material with large band-gap, low dielectric constant, reduced parasitic capacitance and minimal charge transfer induced noise-is used for protein profiling. The corresponding ΔG (change in pore conductance due to analyte translocation) profiles showed a bimodal Gaussian distribution where the lower and higher ΔG distributions were attributed to (pseudo-) folded and unfolded conformations respectively. With increasing voltage, the voltage induced unfolding increased (evident by decrease in ΔG) and plateaued after ∼400 mV of applied voltage. From the ΔG versus voltage profile corresponding to the pseudo-folded state, we calculated the molecular radius of hSTf, and was found to be ∼3.1 nm which is in close concordance with the literature reported value of ∼3.25 nm.
在这项工作中，我们提出了一种 2D 六方氮化硼（h-BN）纳米孔制造的分步工作流程，然后在 pH 值约为 8 的条件下，在从+100 mV 到+800 mV 的应用电压下，利用这些纳米孔来检测全人血清转铁蛋白（hSTf）。2D 纳米孔常用于 DNA 检测，然而，在单分子蛋白质检测方面的文献却存在很大的空白，据我们所知，这是首次使用具有大带隙、低介电常数、寄生电容减小和最小电荷转移诱导噪声的 h-BN 材料来进行蛋白质分析。相应的ΔG（由于分析物转位导致的孔电导变化）图谱显示出双峰高斯分布，其中较低和较高的ΔG 分布分别归因于（拟）折叠和未折叠构象。随着电压的增加，电压诱导的解折叠增加（通过ΔG 的减小来证明），在施加约 400 mV 的电压后趋于平稳。从对应于拟折叠状态的ΔG 与电压的关系图中，我们计算了 hSTf 的分子半径，发现约为 3.1nm，与文献报道的约 3.25nm 值非常吻合。
