(400e) Fabrication of Stable, Single-Hole Capsules Using Particle Lithography

Standard controlled-release drug particles allow drug to escape through the entire particle surface area at a roughly spatially-uniform rate. We take first steps toward creating a ?focused release? particle, which has a single opening that will release material directly into a targeted region. Stable anisotropic particles were fabricated by combining the ?particle lithography? and polyelectrolyte layer-by-layer assembly techniques to form one predictably-sized hole in a robust nanoparticle shell, revealing the underlying loaded microcapsule. The size of the lithographed region is controlled by varying coating sizes and the modified capsules can swell and shrink in response to solution pH. The lithographed shell protects the underlying multilayered polymeric capsules during sonication and allows the capsules to be dehydrated and rehydrated. Our particles remained stable during sonication and from aggregation, due to the small size of the patch region, yet are sufficiently electrostatically charged to serve as reliable foundations for potential further modification with electrostatic or covalent chemistry coatings. Dual functionalities were synthesized onto the particle surfaces, with a 5% region having red fluorescence and a 95% region have green fluorescence. Such dual functionality particles could have great potential as drug delivery vectors, acting as ?colloidal syringes?.