  By considering 5--dimensional cosmological models with a bulk filled with a
pressureless scalar field; equivalently dust matter, and a negative
cosmological constant, we have found a regular instantonic solution which is
free from any singularity at the origin of the extra--coordinate. This
instanton describes 5--dimensional asymptotically anti de Sitter wormhole, when
the bulk has a topology R times S^4. Compactified brane-world instantons which
are built up from such instantonic solution describe either a single brane or a
string of branes. Their analytical continuation to the pseudo--Riemannian
metric can give rise to either 4-dimensional inflating branes or solutions with
the same dynamical behaviour for extra--dimension and branes, in addition to
multitemporal solutions. Dust brane-world models with arbitrary dimensions (D
>= 5) as well as other spatial topologies are also briefly discussed.
