Nanoengineered smart containers for induced drug release

Controlling the drug release is one of the main goals of nanomedicine. Encapsulation makes it possible to reduce toxicity and, at the same time, to increase drug efficacy upon a targeted release in terms of time and/or site specificity. The goal of this research is the development of polymeric nanoengineered smart containers of drug that are able to encapsulate and release the drug in a controlled manner. These smart containers are prepared both in form of capsules and in form of arrays of freestanding microchambers. The main technique used for the fabrication of these systems is the layer-by-layer technique that consists of the alternate adsorption of a polycation (i.e., polyallylammine hydrochloride, polyethylenimine) and a polyanion (i.e., polystyrene sulfonate, polydiallyldimethylammonium chloride) onto a substrate or a sacrificial template, creating upon dissolution or removal of the template capsules or chambers made of polyelectrolytes multilayers (PEM) having the desired shape/size. Since this PEM-based systems are still permeable at small molecules and compounds, we also investigated the possibility of creating microchambers with other materials that are suitable for long-term encapsulation of small molecules (down to 1 kDa). To this aim, we used biodegradable, biocompatible, U.S. Food and Drug Administration (FDA) approved polymers (PLA, PCL, PLGA, PHB), to fabricate microsized drug reservoirs (microchambers) using one-step dip coating technique. Experiments on the drug loading in both capsules and microchambers are also discussed. The morphology of each sample was investigated by Scanning Electron Microscopy (SEM). Furthermore, the Coherent X-ray diffraction imaging technique was employed in the case of capsules. The structure of capsules is significantly different, depending on whether they are under dry conditions or in contact with a liquid medium. The reconstructed image is similar to that showed by SEM micrographs acquired for similar objects. Studies regarding release methods are still in progress.