Stretching of DNA molecules on mica surfaces by magnetic field

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.