Figure 3: Multi-photon Images of Caco-2 cells treated with various molecular weight PEGs (a) Untreated cells were served as control. (b, c) Caco-2 cells were treated with PEG 3350 and PEG 8000 respectively. Cluster thickness decreased when treated with higher molecular weight PEG. The cluster thickness when treated with PEG 8000 was approximately 50 μm. The actin filaments are shown in red and DAPI staining of nuclei is in blue. Bar length=20 μm.