A Photoactivatable Nanopatterned Substrate for Analyzing Collective Cell Migration with Precisely Tuned Cell-Extracellular Matrix Ligand Interactions
Figure 3
Photo-induced cell adhesion on the photoactivatable nanopatterned surface.
(A) Dose-dependent increase of surface cell adhesiveness. The number of cells attached to a given area 3 hours after cell seeding is plotted against the irradiation energy. The error bars represent the standard deviations of the data from 3 different experiments. (B) Comparison of cell adhesiveness of the photoirradiated nanopatterned substrate to a similar surface where gold nanoparticles were functionalized with cRGD alone. The number of cells attached to a given area is plotted. The former surface was irradiated at 10 J before cell seeding. In either case, the glass regions were passivated with PEG2K-silane. The error bars represent the standard deviations of the data from 7 regions. (C, D) SEM images of a single HeLa cell migrating on the photoactivated nanopatterned surface. The image shown in D is a magnified image of the region indicated in C. (E, F) Photopatterning of HeLa cells in a stripe pattern on the nanopatterned surfaces, where gold nanoparticles were functionalized with (E) cRGD and photocleavable PEG12K or (F) photocleavable PEG12K alone. (G, H) Photoinduced cell migration. (G) HeLa cells were initially confined to a circular spot (indicated by the dotted line), and cell migration was induced by irradiating a square region (indicated by the solid line). A cellular image after 21 hours is shown in H. In all experiments, HeLa cells (4×105) were allowed to attach to the surface in serum-free medium for 1 hour, and the unattached cells were removed when the medium was changed to normal serum-containing medium. For C-H, the surfaces were irradiated with near-UV light (λ = 365 nm, 10 J) in PBS before cell seeding.