Layer -by -Layer assembled nanostructured capsules as drug delivery systems

In this talk, the fabrication of polyelectrolyte capsules with silica and calcium carbonate templates by the layer-by-layer (LbL) technique and their subsequent use for delivering drugs will be presented. The LbL method is a versatile route to prepare micro- and nano-capsules with an excellent control of wall thickness, size and shape. The resulting capsule wall is a nanostructured membrane that is responsive to external stimuli. The membrane can further be modified using in-situ synthesized nanoparticles and graphene oxide to make it responsive to light. Several combinations of polyelectrolyte capsules have been synthesized in our lab to encapsulate various drugs. Our primary focus has been on anti-cancer drug delivery and gene delivery. The mechanism of encapsulation and release has been elucidated by confocal and electron microscopy. The encapsulated drug can be released by changing the pH, by enzymatic degradation and by using a laser. Both in vitro and in vivo studies have revealed that the encapsulated drugs have a better efficacy and a higher circulation time. Thus, stimuli responsive polyelectrolyte capsules having nanostructured membranes provide a novel approach to deliver active molecules.