The present disclosure relates to delivery and release systems, such as core-shell particles. An exemplary composition according to the disclosure can include a carrier element forming an outer shell that defines an inner core. The core can include a reactive agent that is adapted to react with the shell, particularly at an inner interface of the shell with the core materials. The reaction can provide an inside-out degradation of the shell and release of one or more materials therein. The reactive agent may be separated from the shell, such as using a phase change material (PCM). Upon reaching specific environmental conditions, the PCM can change so as the release the reactive agent for reaction with the shell. The systems can be used in various methods to deliver a material to various environments, including underground reservoirs.