Vehicles coated with polysaccharides, their preparation and use.

A coated carrier polysaccharide comprising a carrier having a coating of at least two successive layers of polysaccharides, wherein a first layer of polysaccharide spontaneously associates with a second polysaccharide layer that are oppositely charged functional groups or functional groups They are engaging covalently and wherein the first and second polysaccharide layer are different polysaccharides, by their physico-chemical.