Characterization of sonicated breath films by atomic force microscopy

Porous structures offer a vast range of important industrial applications. In the context of medicine, and specifically in the area of controlled drug delivery, spatial [and temporal] control over local porosity has a significant influence on net molecular flux through [membrane-based] controlled release platforms. Such systems may be formulated as oral, transdermal, or even implantable entities, and address chronic infusion needs covering such ailments as diabetes, cancer and hypertension. In all the aforementioned situations, a facility to spatially control porosity could offer significant advantage, such as safer controlled release over extended durations. We have previously described a novel route to engineering-in such flexibility within polymeric thin films by modifying spin-coating protocols to accommodate breath film patterning, that is, the spatially controlled condensation of pore forming droplets onto a liquid-polymer film. Here we demonstrate that those same breath film structures are acoustically responsive. We show, using AFM that the integrity of such films can be compromised to form a leaky structure through which solutions can diffuse. We advocate the use of such films as depot capping structures for controlled drug delivery.