A new scanning probe-based microrheology approach is used to quantify the frequency-dependent
viscoelastic behavior of both fibroblast cells and polymer gels. The scanning probe shape was modified
using polystyrene beads for a defined surface area nondestructively deforming the sample. An extended
Hertz model is introduced to measure the frequency-dependent storage and loss moduli even for thin cell
samples. Control measurements of the polyacrylamide gels compare well with conventional rheological
data. The cells show a viscoelastic signature similar to in vitro actin gels.