Cellular blebs: pressure-driven, axisymmetric,membrane protrusions

Thomas E. Woolley

Eamonn A. Gaffney

James M. Oliver

Ruth E. Baker

Sarah L. Waters

Alain Goriely

November 21, 2013

Abstract

Blebs are cellular protrusions that are used by cells for multiple pur-poses including locomotion. A mechanical model for the problem ofpressure-driven blebs based on force and moment balances in the growthand remodeling of an axisymmetric shell model is proposed. The for-mation of a bleb is initiated by weakening the shell over a small regionand the deformation of the cellular membrane from the cortex is obtainedduring inflation. Past the initial maximal stretch a growth and remod-eling process takes place that results in the formation of large blebs. Itis observed that both geometric and biomechanical are important in thisprocess. In particular it is shown that although blebs are driven by a pres-sure difference across the cellular membrane it is not the limiting factorin determining bleb size.

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