Calcium carbonate microstructures useful in encapsulation applications and a process for the preparation thereof

摘要

A facile method to synthesize stable calcium carbonate microstructures is demonstrated which allows in situ encapsulation of sensitive molecules like drugs. The methodology involves a macromolecular assembly of anionic polypeptide with cationic peptide oligomer to concurrently template and hold to stabilize the mineralized structure. The heterogeneously distributed mixture of anionic and cationic residues in the macromolecular assembly, similar to that is found in natural systems assists in recognizing and coassembling Ca2+ and CO32− ionic clusters, especially for formation of a disordered precursor phase such as amorphous calcium carbonate (ACC) and further crystallization to form a metastable vaterite phase. The assembly also facilitates encapsulation of a guest molecule such as tetracycline at ambient conditions without affecting the mineralization process. The tetracycline-loaded microstructures show excellent antibacterial activities against many Gram-positive and Gram-negative bacterial strains and hence together with the fluorescence property of tetracycline and appropriate drug release profile, they can be used as multifunctional materials for therapeutic and imaging applications.

主权项

1. A stable, controlled release calcium carbonate core-shell microstructure consisting of:
a shell consisting of
an anionic polymer selected from the group consisting of poly(aspartate) and fluorescein isothiocyanate (FITC)-tagged poly(aspartate) with molecular weight of 5-50 kD,a multivalent cationic oligomer selected from the group consisting of tetraethylenepentamine, penta(L-lysine) and fluorescein isothiocyanate (FITC)-tagged penta(L-lysine) and CaCO3;
wherein said anionic polymer and said cationic oligomer are ionically cross-linked to form a macromolecular assembly and said CaCO3 penetrates said assembly to form said shell; and a core consisting of
said anionic polymer andsaid multivalent cationic oligomer;
wherein said anionic polymer and said cationic oligomer are ionically cross-linked to form a macromolecular assembly.