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单分子表面诱导荧光衰逝(single molecule surface-induced fluorescence attenuation, smSIFA)技术是一种基于二维材料受体、用于研究生物大分子法向运动的精密测量方法, 该方法不受二维平面运动的干扰. 作为受体的二维材料, 其特征淬灭距离决定法向上探测的距离和精度. 近年来以氧化石墨烯(graphene oxide, GO)和石墨烯作为介质受体的SIFA技术在生物大分子的研究中发挥了重要作用, 但石墨烯和GO具有固定的特征淬灭距离, 探测范围有限. 调整探测范围需要更换介质材料, 面临材料选择与制备的困难, 亟需开发用于技术的可调控材料. 本文改良了以GO为介质受体的单分子SIFA技术, 利用热还原的方法对GO进行还原, 通过控制还原温度, 制备出了还原程度不同的还原氧化石墨烯(reduced graphene oxide, rGO), 调控特征淬灭距离, 利用荧光标记的DNA测量rGO的特征淬灭距离. 将rGO用于单分子SIFA技术, 对Holliday junction构象变化的观察, 论证了rGO的探测范围.Single-molecular surface-induced fluorescence attenuation (smSIFA) is a precise method of studying the vertical movement of biological macromolecules based on two-dimensional material receptors. This method is not affected by two-dimensional planar motion of membrane or proteins. However, the detection range and accuracy of vertical movement are determined by the properties of two-dimensional materials as receptors. In recent years, surface induced fluorescence attenuation based on graphene oxide and graphene has played an important role in studying biomacromolecules. However, the detection range of graphene and graphene oxide are limited owing to the fixed and limited characteristic quenching distance. Adjusting the detection range requires replacing the medium material, which poses difficulties in selecting and preparing materials. Therefore, it is urgently needed to develop controllable materials for single-molecular SIFA. In this study, the single-molecule SIFA with graphene oxide as the medium acceptor is improved by reducing graphene oxide through thermal reduction. By controlling the reduction temperature, reduced graphene oxides to different reduction degrees are prepared and the characteristic quenching distances are adjusted. The characteristic quenching distance is measured by fluorescent labeled DNA. Single-molecule SIFA based on reduced graphene oxide is used to observe the conformational changes of Holliday junction, and the detection range of reduced graphene oxide is demonstrated.
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Keywords:
- reduced graphene oxide /
- surface-induced fluorescence attenuation /
- characteristic quenching distance /
- fluorescence resonance energy transfer








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