纳米孔道单分子电化学测量的低噪音控温系统研究

纳米孔道检测技术是一种利用单个分子测量界面实现在单分子水平上测量DNA、RNA、蛋白、多肽等生物分子的高灵敏的单分子检测技术. 由于单个分子与纳米孔道的相互作用受热力学控制，亟需精准控制纳米孔道单分子分析的实验温度. 因此，本文研制了一种低噪音控温系统用于具有皮安级电流分辨的纳米孔道单分子实验，以实现精确调控测量时的环境温度. 该系统利用半导体制冷片的热电效应对检测池环境加热/制冷，通过对高精度热敏电阻进行电磁屏蔽以实现在温度反馈的同时避免噪音的引入. 利用比例-积分-微分算法进行控制，达到高精度快速控温的要求. 该系统控温精度为±1 °C，无额外噪音引入至超灵敏纳米孔道单分子测量，获得了25 °C到5 °C下Poly(dA)5与单个气单胞菌溶素（Aerolysin）分子界面间作用产生信号的差异，应用于研究单分子与纳米孔道相互作用的热力学行为.

A Low Noise Temperature Control System for Nanopore-Based Single Molecule Analysis

Nanopore employs a single bio-molecule interface, which is a highly sensitive single-molecule detection technology for measuring single biomolecules such as DNA, RNA, protein, and peptide. The interaction between single molecule and nanopore is thermodynamically controlled. Therefore, it is urgent to precisely control the temperature of the nanopore system without introduction of any noise. In this paper, we have developed a low-noise temperature control system for single-molecule detection of nanopores to achieve precise regulation at the ambient temperature during measurements. The system utilizes the thermoelectric effect of the semiconductor refrigerating chip to heat or cool the detection chamber, while adopts electromagnetically shielded high-precision thermistor to achieve the temperature feedback which avoids the introduction of noise at the same time. The proportional-integral-differential algorithm is used to provide the high-precision and rapid temperature control. The system was further applied in measuring the interaction between Poly(dA)5 and aerolysin nanopore at 25 ^oC to 5 ^oC. This system could be used to characterize the thermodynamic and kinetic information of the single molecules.