Fabrication of polyurethane microcapsules with different shapes and their influence on cellular internalization.

The shape of particles is recognized as an important parameter to influence their interactions with cells. In this study, spherical and discal polyurethane microcapsules were prepared via an adsorption and crosslinking method on the templates with corresponding shapes in organic solvent. Both types of capsules could be well dispersed in aqueous medium and maintain their original shapes. The internalization behaviors of the microcapsules were investigated by co-incubation with RAW 264.7 and HepG2 cells. Compared with the spherical capsules, the discal microcapsules could be internalized with faster rate and higher amount by both types of cells. Both types of capsules did not show significant cytotoxicity even after co-incubation for 72h at a high ratio of capsule to cell.