We present a simple and facile approach to fabricate biocompatible hollow microparticles of controlled geometry undergoing shape-dependent cellular uptake.   The hemispherical, spherical and cubical microparticles were obtained by drying multilayer capsules of hydrogen-bonded poly(N-vinylpyrrolidone)/tannic acid (PVPON/TA)n.  That shape transformation was controlled by capsule stiffness which was regulated by the layer number, capsule diameter, and PVPON molecular weight.  The hemispherical particles were produced from spherical capsules when this ratio was in the range from 0.041 to 0.055. Opening in the hemispherical particles was modulated by the initial shell thickness which was controlled by the number of deposited polymer layers in the initial multilayer shell. We also found that increase in capsule wall thickness prevented cubical and spherical capsules from collapsing upon drying. These structures maintained their three-dimensional shapes in the dry state and upon rehydration.  The cell growth and viability studies using human cancer cells showed noncytotoxic properties of the capsules. Finally, we revealed that spherical and hemispherical capsules were internalized by macrophages with the uptake of the hemispherical particles per cell two times more efficient. The method presented here allows for a robust preparation of biocompatible shaped particles whose shape and dimensions can be easily tuned by controlling capsule size and wall thickness. The reported structures can be potentially useful for biomedical applications such as shape-controlled cellular uptake and flow dynamics.

Biocompatible shaped particles from dried multilayer polymer capsules for cellular uptake

247th National Meeting (2014)

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