Figure 3.

Magnetic nature of MFM responses. (A) Schematic of the experiment with the MFM probe polarized vertically up (left picture) and vertically down (right picture). (B) AFM images of two areas of a primary cultured biotinylated SMC measured with the MFM tip polarized “up” (left column) and “down” (right column). (C) Corresponding MFM images for the two selected cell areas. Note that for magnetic repolarization, the MFM probe had to be removed from the instrument; therefore, the images on the left and right do not exactly represent the same area of the cell. (D) Comparison of the topographic (AFM) and magnetic (MFM) profiles (respectively shown by straight lines in B and C) for a single superparamagnetic microbead for different polarizations of the MFM tip. Black and blue lines depict variations in the AFM height and the MFM voltage, respectively.