Methods for the preparation of polymer-templated core-shell nanoparticles include the steps of (a) preparing a cationic polymeric core material comprising polymeric micelles, and (b) coating the core material with a silica-comprising shell by depositing the shell onto the polymeric micelles from at least one silica precursor to form the core-shell nanoparticles. Compositions which include the core-shell nanoparticles are adapted to facilitate controlled delivery of at least one active agent into a system in response to controlled changes in the pH of the system.
