title: Combining laser microsurgery and finite element modeling to assess cell-level epithelial mechanics.
abstract: Laser microsurgery and finite element modeling are used to determine the cell-level mechanics of the amnioserosa-a morphogenetically crucial epithelium on the dorsal surface of fruit fly embryos (Drosophila melanogaster). In the experiments, a tightly focused laser ablates a subcellular hole (1 microm in diameter) that passes clean through the epithelium. The surrounding cells recoil from the wound site with a large range of initial recoil velocities. These depend on the embryo's developmental stage and the subcellular wound site. The initial recoil (up to 0.1 s) is well reproduced by a base finite element model, which assumes a uniform effective viscosity inside the cells, a constant tension along each cell-cell boundary, and a large, potentially anisotropic, far-field stress--one that far exceeds the stress equivalent of the cell-edge tensions. After 0.1 s, the experimental recoils slow dramatically. This observation can be reproduced by adding viscoelastic rods along cell edges or as a fine prestressed mesh parallel to the apical and basal membranes of the cell. The mesh also reproduces a number of double-wounding experiments in which successive holes are drilled in a single cell.
authors.affiliation: Department of Physics & Astronomy, Vanderbilt University, Nashville, Tennessee, USA. shane.hutson@vanderbilt.edu
authors.forename: M Shane
authors.initials: MS
authors.lastname: Hutson
authors.forename: J
authors.initials: J
authors.lastname: Veldhuis
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Ma
authors.forename: Holley E
authors.initials: HE
authors.lastname: Lynch
authors.forename: P Graham
authors.initials: PG
authors.lastname: Cranston
authors.forename: G Wayne
authors.initials: GW
authors.lastname: Brodland
mesh_terms: D000818:Animals; D016880:Anisotropy; D001696:Biomechanical Phenomena; D004331:Drosophila melanogaster; D004847:Epithelial Cells / Q000378:metabolism* / Q000528:radiation effects*; D020342:Finite Element Analysis; D053685:Laser Therapy; D008866:Microsurgery; D008954:Models, Biological; D013997:Time Factors