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）技术已发展成为单分子实验中不可或缺的工具：当单个分子穿过纳米级孔径时，可通过其引发的离子流获取DNA/RNA的特征信息。然而，由于背景电流噪声相对较高、测量带宽较低，难以从纳米孔记录系统的本征噪声中区分出分子特异性信号，这限制了其在DNA测序中的应用。本文提出一种基于共识滤波的新型降噪方法，可显著提升降噪后电流轨迹的准确性与信噪比（SNRs）。该方法与传统贝塞尔滤波器进行了对比，并通过分析模拟的典型易位数据以及α-溶血素（α-HL）纳米孔实验数据完成验证。研究表明，该方法可显著抑制由放大器与模数转换电路（ADC）的电压噪声所产生的高频噪声，且能以超越传统贝塞尔滤波器的精度恢复部分被掩盖的短时易位事件。