Transient pores in stretched vesicles: role of leak-out

We have visualized macroscopic transient pores in mechanically stretched gi ant vesicles. They can be observed only if the vesicles are prepared in a v iscous solution to slow down the leak-out of the internal liquid. We study here theoretically the full dynamics of growth (driven by surface tension) and closure (driven by line tension) of these large pores. We write two cou pled equations of the time evolution of the radii r(t) of the hole and R(t) of the vesicle, which both act on the release of the membrane tension. We find four periods in the life of a transient pore: (I) exponential growth o f the young pore; (II) stop of the growth at a maximum radius ih,; (III) sl ow closure limited by the leak-out; (IV) fast closure below a critical radi us, when leak-out becomes negligible. Ultimately the membrane is completely resealed. (C) 2000 Elsevier Science B.V. All rights reserved.