ELECTRICAL NOISES REDUCTION IN NANOPORES EXPERIMENTS BASED ON CONSENSUS FILTER

Nanopore has developed into an indispensable tool for single molecules experiments, where useful information about the characteristics of DNA/RNA can be obtained from the flowing of ionic current elicited by individual molecules as they traverse a single nanometer-scale aperture. However, due to the relatively high background current noise and low measurement bandwidth, it is difficult to distinguish the molecule-specific signals from the intrinsic noises of the nanopore recording systems, which impeded its application in DNA sequencing. In this paper, we present a novel consensus filter-based noise reduction approach, which considerably improves the accuracy of the noise-filtered current traces and the signal-to-noise ratios (SNRs). The new approach is compared to the conventional Bessel filters and validated by analyzing simulated representative translocation data as well as alpha-Hemolysin (α-HL) nanopore experimental data. It is demonstrated that the high frequency noise generated by the voltage noise of the amplifier and Analog-to-Digital converter circuits (ADC) can be significantly reduced and some hidden short-lived translocation events can be recovered with satisfying accuracy beyond the conventional limitations of the Bessel filters.

纳米孔（Nanopore）技术已发展为单分子实验领域不可或缺的核心工具：当单个生物分子穿过纳米级孔径时，会引发离子电流的动态变化，研究人员可借此获取DNA/RNA的特征相关有效信息。然而，由于背景电流噪声相对较高且测量带宽有限，难以从纳米孔记录系统的固有噪声中区分出分子特异性信号，一度阻碍了其在DNA测序中的应用。本文提出一种基于一致性滤波的新型降噪方法，该方法可显著提升降噪后电流轨迹的准确性与信号信噪比（signal-to-noise ratios, SNRs）。本文将所提方法与传统贝塞尔（Bessel）滤波器进行对比，并通过分析模拟的典型易位数据以及α-溶血素（alpha-Hemolysin, α-HL）纳米孔实验数据对其进行验证。实验结果表明，放大器与模数转换器（Analog-to-Digital converter circuits, ADC）电路的电压噪声所产生的高频噪声可被显著抑制，同时还能以优于传统贝塞尔滤波器的精度，恢复出部分被隐藏的短时易位事件。