Driving Forces for Single DNA Stretching Assessed by In Situ TIRFM  

作　　者：Jinli Han Ting Zhang Xiaochun Zhou 

机构地区：[1]Key Laboratory of the Ministry of Education for Advanced Catalysis Materials,Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces,Institute of Physical Chemistry,Zhejiang Normal University,Jinhua 321004,China [2]Division of Advanced Nanomaterials,Suzhou Institute of Nano-tech and Nano-bionics,Chinese Academy of Sciences(CAS),Suzhou 215123,China

出　　处：《Chemical & Biomedical Imaging》2023年第2期140-146,共7页化学与生物医学影像（英文）

基　　金：support from the National Key R&D Program of China from the Ministry of Science and Technology(2020YFB1505700);Open Research Fund of Key Laboratory of the Ministry of Education for Advanced Catalysis Materials and Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces,Zhejiang Normal University(KLMEACM 202209);Suzhou Science and Technology Plan Project,Suzhou Carbon Peak Carbon Neutralization Technology Support Key Project(No.ST202214).

摘　　要：Herein,single DNA molecule stretching in a hydrodynamic flow was monitored by in situ total internal reflection fluorescence microscopy(TIRFM).Different driving forces for DNA stretching were assessed systematically.The binding force between the substrate and the DNA molecule significantly affected the dynamic stretching behavior of coiled DNA,where DNA stretched only on the substrate modified by−NH_(2) due to electrostatic adsorption.Proper flow force from the fluid was favorable for DNA stretching,which was in stark contrast to DNA stretching restricting at a lower flow rate or washing off DNA molecules at a higher flow rate of fluid.Moreover,DNA stretching was restricted in low pH solution but improved in high pH solution.This is due to the confrontation between contractive and repulsion forces in coiled DNA molecules in different pH,which is related to the Donnan equilibrium in a single condensed DNA molecule.Additionally,external Na+would break this Donnan equilibrium,leading to a restriction for DNA stretching.This study will guide quantitative dynamics studies of DNA stretching in the future.

关 键 词：DNA stretching TIRFM in situ imaging driving force hydrodynamic flow stretching 

分 类 号：O35[理学—流体力学]