Abstract
Multicompartmental capsules have demonstrated value in fields ranging from drug release, mimetics of artificial cells, to energy conversion and storage. However, the fabrication of devices with different compartments usually requires the use of toxic solvents, and/or the adaptation of technically demanding methods, including precision microfluidics and multistep processes. The spontaneous formation of multi-core capsules resulting from polyelectrolyte complexation at the interface of a prototypic all-aqueous two-phase system is described here. The variation of polyelectrolyte concentration and complexation time are described as simple working parameters capable of driving the formation of compartments at different yields, as well as tailoring their morphology. The mild processing technology enables the encapsulation of animal cells, which are capable of invading capsule walls for specific processing conditions.