title: Scaling of traction forces with the size of cohesive cell colonies.
abstract: To understand how the mechanical properties of tissues emerge from interactions of multiple cells, we measure traction stresses of cohesive colonies of 1-27 cells adherent to soft substrates. We find that traction stresses are generally localized at the periphery of the colony and the total traction force scales with the colony radius. For large colony sizes, the scaling appears to approach linear, suggesting the emergence of an apparent surface tension of the order of 10(-3)  N/m. A simple model of the cell colony as a contractile elastic medium coupled to the substrate captures the spatial distribution of traction forces and the scaling of traction forces with the colony size.
authors.affiliation: Department of Physics, Yale University, New Haven, Connecticut 06520, USA.
authors.forename: Aaron F
authors.initials: AF
authors.lastname: Mertz
authors.forename: Shiladitya
authors.initials: S
authors.lastname: Banerjee
authors.forename: Yonglu
authors.initials: Y
authors.lastname: Che
authors.forename: Guy K
authors.initials: GK
authors.lastname: German
authors.forename: Ye
authors.initials: Y
authors.lastname: Xu
authors.forename: Callen
authors.initials: C
authors.lastname: Hyland
authors.forename: M Cristina
authors.initials: MC
authors.lastname: Marchetti
authors.forename: Valerie
authors.initials: V
authors.lastname: Horsley
authors.forename: Eric R
authors.initials: ER
authors.lastname: Dufresne
mesh_terms: D000818:Animals; D002122:Calcium Chloride; D002448:Cell Adhesion / Q000502:physiology*; D002450:Cell Communication / Q000502:physiology*; D002452:Cell Count; D003470:Culture Media; D015603:Keratinocytes / Q000166:cytology*; D051379:Mice; D008954:Models, Biological
chemical_list: D003470:Culture Media; D002122:Calcium Chloride