Bio-inspired fabrication and potential applications of hierarchically porous CaCO3 hollow nanospheres

Abstract

A simple and bio-inspired strategy is reported for the first time to fabricate sea urchin-shaped hollow CaCO₃ nanospheres (HCNSs) with a hierarchically porous hollow structure under the mediation of soybean trypsin inhibitor (STI). The hierarchically porous structure makes the HCNSs exhibit not only a high loading capacity but also a prolonged release time by the stepwise release of DOX from the mesoporous structure. Through in vitro experiments, we found that the entry of the hierarchical HCNSs into HeLa cells possibly involved an extracellular decomposition, due to the extracellular and intracellular acid microenvironment of solid tumor tissues, and a subsequent endocytosis pathway. In view of the pH-sensitive property as well as the hierarchically porous hollow structure, as well as the excellent biocompatibility and biodegradability of the as-prepared HCNSs, the hierarchically porous hollow CaCO₃ could be a promising candidate as an anticancer drug carrier, and would be of great importance in practical and clinical use.