  Carefully designed micro and nanocarriers can provide significant advantages
over conventional macroscopic counterparts in biomedical applications. The set
of requirements including a high loading capacity, triggered release
mechanisms, biocompatibility, and biodegradability should be considered for the
successful delivery realization. Porous calcium carbonate (CaCO3) is one of the
most promising platforms, which can encompass all the beforehand mentioned
requirements. Here, we study both the particles formation and biological
applicability of CaCO3. In particular, anisotropic differently shaped CaCO3
particles were synthesized using green sustainable approach based on
co-precipitation of calcium chloride and sodium carbonate/bicarbonate at
different ratios in the presence of organic additives. The impact of salts
concentrations, reaction time, as well as organic additives was systematically
researched to achieve controllable and reliable design of CaCO3 particles. It
has been demonstrated that the crystallinity (vaterite or calcite phase) of
particles depends on the initial salts concentrations. The loading capacity of
prepared CaCO3 particles is determined by their surface properties such as
specific surface area, pore size and zeta-potential. Differently shaped CaCO3
particles (spheroids, ellipsoids, toroids) were used to evaluate their uptake
efficiency on the example of C6 glioma cells. The results show that the
ellipsoidal particles possess a higher probability for internalization by
cancer cells. All tested particles were also found to have a good
biocompatibility. The capability to design physicochemical properties of CaCO3
particles has a significant impact on drug delivery applications, since the
particles geometry substantially affects cell behavior (internalization,
toxicity) and allows outperforming standard spherical counterparts.
