Core-shell architectures containingpoly (ethylene imine) (PEI) as a core and poly(lactide) (PLA) as arms were prepared. PEI was used as macroinitiator for ring opening polymerization of lactide. PEI-PLA core-shell architectures were able to encapsulate guest molecules. Size of the core-shell architectures was between 10-100 nm, hence they can be considered as nanocarriers to transport the guest molecules. Transport capacity of nanocarriers depends on their nano-environments and type of self-assembly in solvent. In solid state nanocarriers self-assemble as long structures with nano-size diameter or they form network structures. Aggregations type depends on the concentration of nanocarriers in solution. Effect of the shell thickness and aggregation type on the release rate is also investigated.