Scanning probe-based frequency-dependent microrheology of polymer gels andbiological cells

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