We study the motion of single trapped microtracers immersed in F-actin solutions by optical trapping interferometry in order to clarify the observed variability of their anomalous power-law exponent. We obtain a local 7/8 exponent only for non-adsorbing polymer at low optical trapping forces, a value which decreases when increasing the trap stiffness. The velocity autocorrelation function confirms the complex interplay in the colloid-polymer system even under the influence of small external forces and shows an additional constant power-law exponent for the depleted particles.
Comment: 5 pages, 5 figures. Submitted to Physical Review Letters. arXiv admin note: substantial text overlap with arXiv:2209.07159