Stretching of DNA molecules on mica surfaces by magnetic field
Feifei WangYing WangTingting HuangFenfen GuoJinyun LiuZhengxun SongZhankun WengZuobin WangZuobin Wang
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Abstract:
This paper presents a method for the stretching of DNA molecules on mica surfaces by magnetic field. In the experiment, the magnetic fields with different intensities were generated using a cylindrical coil and were used to study their effects on DNA molecules. The magnetic field intensity was controlled by the electric current flowing through the coil. The imaging of DNA molecules was performed by atomic force microscope (AFM) in the same position on the mica surface after the treatment with the magnetic field. It was found that the DNA molecules were gradually straightened with the increase of magnetic field intensity, and the straightening performance was better than that of the molecular combing method in the experiment. In addition, the degree of DNA straightening was related to the speed at which DNA molecules were dropped to the mica surface, the amount of DNA charges and the direction of magnetic field.Keywords:
Combing
Intensity
Biomagnetism
Atomic force microscopy (AFM; also called scanning force microscopy [SFM]) is a rather novel technique that offers unique advantages in the potential for the very high resolution of DNA and small ligands in the absence of stains, shadows, and labels (,). Furthermore, the scanning can be performed in air or liquid. The latter is particularly important for resolving fully hydrated structures. The AFM is theoretically capable of resolving structural details at the level of atomic dimensions, provided that the specimen is not dynamic.
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The surface topography of mica modified by 3-(trimethoxysilyl)propyl methacrylate(KH-570) was studied by atomic force microscope(AFM).Surface parameters such as roughness Rq,particle height D and the highest value at Z direction were measured.The influence of several factors on the surface topography of modified mica was investigated,including rinse,the concentration of KH-570 and the order of rinse and drying.The results indicated that the value of Rq was affected by the point defect on mica surface,rinse and the disposal after modification,while the morphology of KH-570 molecular aggregate was depended on the concentration of KH-570.As the concentration reduced,the morphology changed from cross-linked web to divergent points.
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