Intelligent micro- and nanocapsules

This work reports about the construction and properties of a new type of designer capsules with dimensions from some 10 nm to mu m and with nm dimensions of the wall. They are prepared by consecutive adsorption of oppositely charged polyelectrolytes on a colloidal particle that is later sacrificed. By proper selection of materials and conditions the properties, in special permeability and mechanical modulus, can be tuned and switched. This can be made use of in enzymatic synthesis in microvolumes as well as to produce stimuli sensitive gels inside. Via designed composition gradients across the wall photoinduced vectorial electron transfer can be achieved. Due to the high modularity and versatility the system presents a platform for many applications in medicine, pharmacy, biotechnology, food technology, cosmetics or detergency. (c) 2005 Elsevier Ltd. All rights reserved.