Figure 3.

Deactivation of surface effects in the experiments and simulations. (a) Schematic illustration of the method for the spatiotemporally controlled photoconversion of blebbistatin and local killing of cells is shown. A programmable digital micromirror display system is used for projecting blue light on predefined regions of the sample. The culture medium is supplemented with blebbistatin before exposure. Three areas are selected for the treatment: 1) the wound edge, 2) the region between the wound edge and the outline, and 3) the peripheral region. Cell viability staining (live, green and dead, red) and temporal sequence of wound area for microtissues that went through a treatment in (b) area 3 and (c) area 1 are shown. Scale bars, 100 μm. (d) A box plot showing relative closure rates of microtissues that went through treatment in three different regions (n = 12) is given. Closure rates were measured 10 h after light exposure. The median of incision gap closure without any treatment is the reference control and corresponds to 1. Statistical analysis: unpaired Student’s t-test, ^∗P ≤ 0.05. (e) Finite-element simulation of a microtissue with a central hole is shown. The surface contractile modulus is set to zero around the hole throughout the simulation (highlighted in red). Displacement (left) and stress distribution (right) at the equilibrium state are shown. Scale bars, 150 μm. To see this figure in color, go online.