The scientific objective of the research carried out in this International Research Staff Exchange Scheme, is the development of a new technology to effectively deliver siRNA to cancer cells by the embedding of a polyplex into the multilayers and multifunctional nanocapsules. We propose to target pro-survival and anti-apoptotic factors in human cancer cells by using siRNA encapsulated into polyelectrolytes nanocapsules.When siRNAs are formulated into degradable polymer nanocapsules they may be protected from nuclease digestion and last longer than naked siRNAs improving their efficacy and therapeutical properties. These capsules will be prepared by the LbL deposition of interacting polymers onto a sacrificial porous colloidal template followed by core removal. Nanoengineered micro-nanocapsules composed of sequentially assembled polymer layers hold immense promise for a variety of biomedical applications. Furthermore the optimization of intracellular pathway of nanostructures may likely be a key for the development of effective nanoparticles based targeted therapeutics. As the challenge of siRNA delivery by nanocapsules is met, it will be possible to advance RNAi therapeutics rapidly into clinical studies for many diseases, including some which remain untreatable or poorly treated by conventional drugs.