量子式“瞬时事件”类信号的交流式捕捉与解析方法

Carrying out investigations in the micro/nanometer scale and within the biological system has become the mainstream of electroanalytical chemistry currently. There is a typical category of signals in the above scale and/or system. The signals are characterized by that they are very weak, short-lived, and always appear as individual stochastic “transient events” (e.g. the signals induced by collision of single nanoparticle onto an ultramicroelectrode, or traversing of single biomacromolecule through a nanopore, or releasing of single vesicle from a cell). This kind of signals is always directly associated with the properties or patterns of behavior of single particle, thus the capture and analysis of the signal is of significant importance. The traditional characterization method for this kind of signal is dc amperometric technique whose shortcoming is the lack of adequate resolution. In order to overcome this shortcoming, this proposal plans to replace the dc based approach with ac method. By applying a sinusoidal potential to the system under investigation and converting the obtained current response into the frequency domain with mathematic tools, the instant vector corresponding to each “transient event” can be monitored. A sudden change in the amplitude or phase angle component of the instant vector indicates the occurrence of the “transient event”, and the signal induced thereafter can be subtracted and analyzed in both time and frequency domains. The proposed method can provide the voltammograms, power spectra, and phase angles of each harmonics, corresponding to each individual “transient event”, and multidimensional resolution can thus be obtained. The proposed method has the potential to be employed as new tools for single nanoparticle detection, single molecule analysis, nanopore based third generation (single molecule) gene sequencing, and etc..

在微纳米尺度和生物体系开展研究已经成为当今电分析的主流。在上述尺度和体系中有一类信号，其特点是信号以单个独立“瞬时事件”的方式随机出现，且信号幅度小、持续时间短（如单纳米粒子碰撞到微电极、单生物大分子通过纳米孔、细胞释放单个囊泡等所产生的信号）。这类信号往往与单个粒子的特征或行为规律直接相关，对其进行研究有重要意义。这类信号的传统研究方法是直流安培法，其主要缺陷是分辨率不足。针对该缺陷本项目拟建立一种基于交流的方法替代传统方法。通过在研究体系上施加特定的正弦波，并利用时频转换工具对响应信号进行解析，可实现对响应信号瞬时矢量的实时监测。瞬时矢量的幅度或相位的瞬间跳变意味着“瞬时事件”的发生，其所产生的信号可进一步在时域和频域予以解析。该方法可同时提供伏安图、频谱图、相位、谐波等丰富的信息，具有多尺度的分辨率。该方法有望为单粒子检测、单细胞分析，甚至第三代（单分子）基因测序等提供新的工具。

在微纳米尺度和生物体系开展研究已经成为当今电分析的主流。在上述尺度和体系中有一类信号，其特点是信号以单个独立“瞬时事件”的方式随机出现，且信号幅度小、持续时间短。这类信号往往与单个粒子的特征或行为规律直接相关，对其进行研究有重要意义。这类信号的传统研究方法是直流安培法，其主要缺陷是分辨率不足。..针对该缺陷本项目拟建立一种基于交流的方法替代传统方法。通过在研究体系上施加特定的正弦波，并利用时频转换工具对响应信号进行解析，可实现对响应信号瞬时矢量的实时监测。瞬时矢量的幅度或相位的瞬间跳变意味着“瞬时事件”的发生，其所产生的信号可进一步在时域和频域予以解析。..本研究从研制具有任波波形发生、pA级超微电流检测、Msps级高速数据采集能力的伏安仪以及对应的数据处理软件为切入点。借助该仪器平台对“瞬时事件”所对应电化学过程的伏安图还原能力以及相位解析能力，揭示了微汞滴在电极表面的生长物理化学过程机理，微乳滴界面上的电子转移与离子转移耦合过程机理，纳米簇在界面的形成机理；建立了基于微纳离子穿过微管时相位的不同来对微粒进行区分的方法。