The internalisation efficiency and cytotoxicity of polymeric microparticles and capsules were studiedfor three different adherent cell lines: HeLa (human cervice cancer), MCF-7 (human breast cancer)and B104 (murine neuroblastoma). Microparticles of colloidal CaCO3 cores coated with either layerby-layer self-assembled oppositely charged biosynthetic (PSS\PAH) or biodegradable (DXS\PRM)polyelectrolytes and hollow capsules thereof, obtained upon removal of the CaCO3 cores by EDTA,were fabricated. Fluorescent-labeled polymer layers coated onto CaCO3 cores were employed forevaluating cell uptake efficiency. Confocal laser scanning microscopy was used to confirm dissolutionof preformed biodegradable multilayers. Cellular viability for all type of colloidal entities waspreserved, indicating safety and tolerability of the potential drug carriers.