Nacre, bones, and teeth are perfectly designed organic/inorganic composite materials with exceptional mechanical properties. Numerous approaches were taken to synthetically prepare such composites, which in few cases performed structures that came close to the natural idol. Unfortunately, these methods are quite elaborate and not yet suited to produce materials with dimensions above the microscale. The presented work describes a way of creating CaCO3 composites by mineralizing bulk materials in larger scale following the approach of �bio-induced� mineralization. The introduced method uses immobilized urease to induce and limit CaCO3 crystallization inside a polymer conetwork. For that reason suitable conetworks were prepared, which allow urease to be dissolved in the monomeric mixture and that retain the enzymatic activity after polymerization. The bioactive polymer conetworks were then treated with an aqueous mixture of urea and CaCl2. The catalyzed hydrolysis of urea to CO32- and NH4+ allows forming crystals within several hours at room temperature selectively within the bulk. The effect of the conetwork composition, immobilized urease concentration and temperature of calcification were investigated. All named parameters strongly affect the morphology of grown crystals inside the networks. This way, beside spherical, monolithic clusters also bar-like nanocrystals in spherical or dendritic arrays can be formed. Grown crystals are capable of improving stiffness of the starting material up to 700-times, provided that the microstructure shows a dense construction without pores. The process has the potential to generate a new class of hybrid materials that would be available in macroscopic scale for use in light-weight-design and medicine.

Selective CaCO<sub>3 </sub>formation within hydrogels

248th National Meeting (2014)

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Selective CaCO3 formation within hydrogels

Selective CaCO₃formation within hydrogels