Doxorubicin (DOX) is one of mainstays in anticancer therapy due to its universal anticancer activity. Development of DOX delivery systems is of particular importance aiming a reduction in its non-targeted toxicity and improvement of the treatment efficiency. In this study, biodegradable polyelectrolyte multilayer capsules from a dextran sulfate (DS) and poly-l-arginine (Parg) couple for intracellular DOX delivery has been developed. The capsules were fabricated by layer-by-layer (LbL) technique using vaterite particles (500 ± 100 nm) as sacrificial templates. An elegant approach for simultaneous miniaturization of the capsules down to a size of 290 ± 60 nm and DOX loading was elaborated. Cytotoxicity of the DOX-loaded capsules was evaluated in vitro using human breast adenocarcinoma MCF-7 and DOX-resistant MCF-7/ADR cells. Penetration and accumulation of the capsules in the cells were studied by confocal microscopy and flow cytometry. The pronounced accumulation of the DOX-loaded shrunken capsules in MCF-7/ADR cells suggested overcoming drug resistance. The developed capsules could be promising for both anticancer therapy and diagnostic purposes.KeywordsPolyelectrolytesBiodegradable capsulesDextran sulfatePoly-l-arginineLayer-by-layer (LbL) assemblyTemperature induced shrinkingMCF-7 cellsMCF-7/ADR cellsDrug resistance