Formulation and cytotoxicity of doxorubicin loaded in self-assembled bio-polyelectrolyte microshells

A bio-polyelectrolyte microshell composed of alginate sodium (ALG) and chitosan (CHI) was fabricated by electrostatic layer-by-layer (LbL) self-assembly technique. The resulting ALG-CHI microshells were found to be able to effectively load anti-cancer drug doxorubicin (DOX) in the interior of the shells under modest conditions without addition of other reagents, as demonstrated by confocal laser scanning microscopy (CLSM). The mass of DOX loaded in one capsule of four alginate/chitosan layers (i.e. the volume V = 2.5 × 10−10 cm3) is calculated as ca. 1.4 × 10−13 g, which corresponds to 1.5 × 108 DOX molecules. Also, the release of DOX in the shells is dependent on the number of assembled layers of the shells. Colorimetric XTT cell viability assay results showed that the DOX-loaded microshells at high concentrations tested could kill cancer cells more efficiently than free-DOX alone.