Figure 4.

Torsion profile of the Protein G–IgG complex sandwiched between a particle and the glass substrate. (a) The particle orientation as a function of time in a magnetic field rotating in the anti-clockwise direction and in the clockwise direction, respectively. (Solid lines) Orientation of the magnetic field, which is turned off from t = 7 s to t = 8.5 s. (b) The rotational response measured at different field strengths. (c) From the maximum angular excursion, i.e., when the particle starts to remagnetize, the torsional spring constant is determined at the corresponding twisting angle.