Loading capacity versus enzyme activity in anisotropic and spherical calcium carbonate microparticles

A new method of fabrication of calcium carbonate microparticles of ellipsoidal, rhomboidal and spherical geometries is reported by adjusting the relative concentration ratios of the initial salt solutions and/or the ethylene glycol content in the reaction medium. Morphology, porosity, crystallinity and loading capacity of synthesized CaCO3 templates were characterized in detail. Particles harbouring dextran or the enzyme guanylate kinase were obtained through encapsulation of these macromolecules using the layer-by-layer assembly technique to deposit positively and negatively charged polymers on these differently shaped CaCO3 templates and were characterized by confocal laser scanning fluorescence microscopy, fluorometric techniques, and enzyme activity measurements. The enzymatic activity – an important application of such porous particles and containers – has been analyzed in comparison to the loading capacity and geometry. Our results reveal that the particles' shape influenced on morphology of particles and as result affects the activity of the encapsulated enzyme, in addition to the earlier reported influence on cellular uptake. These particles are promising candidates for efficient drug delivery due to their relatively high loading capacity, biocompatibility, and easy fabrication and handling