Shape-dependent cellular processing of polyelectrolyte capsules.

Particle shape is emerging as a key design parameter for tailoring the interactions between particles and cells. Herein, we report the preparation of rod-shaped layer-by-layer (LbL)-assembled polymer hydrogel capsules with tunable aspect ratios (ARs). By templating spherical and rodlike silica particles, disulfide-stabilized poly(methacrylic acid) hydrogel capsules (PMA HCs) with different ARs (from 1 to 4) are generated. The influence of capsule AR on cellular internalization and intracellular fate was quantitatively investigated by flow cytometry, imaging flow cytometry, and fluorescence deconvolution microscopy. These experiments reveal that the cellular internalization kinetics of PMA HCs are dependent on the AR, with spherical capsules being internalized more rapidly and to a greater extent compared with rod-shaped capsules. In contrast, the capsules with different ARs are colocalized with the lysosomal marker LAMP1, suggesting that the lysosomal compartmentalization is independent of shape for these soft polymer capsules.