The present invention provides, among other things, a particle which includes a core comprised of self-assembled one or more nucleic acid molecules, the core being characterized by an ability to adopt at least two configurations: a first configuration having a first greatest dimension greater than 2 μm and a second configuration having a second greatest dimension less than 500 nm, wherein addition of a film coating converts the core from its first configuration to its second configuration. Methods of making and using of provided particles are also disclosed.
