Primary Human hepatic stellate cells cultured in synthetic polyethylene glycol gels with RGD for 5 days. Red: phalloidin actin stain. Green: antibody collagen stain. Blue: DAPI nucleus stain. Inset shows calcein-stained hepatic stellate cell (green) encapsulated in a synthetic polyethylene glycol gel embedded with fluorescent beads (blue). A healthy cell’s cytoskeleton is depolymerized using Cytochalasin D. Change in bead position is captured and analyzed along with the gel’s stiffness to calculate the three-dimensional traction force of the cell using Imaris software. System Zeiss LSM 880 with Imaris Software.