Fabrication and potential applications of CaCO3–lentinan hybrid materials with hierarchical composite pore structure obtained by self-assembly of nanoparticles

Abstract

Chemically designed, hierarchical composite pore materials, with two or more different sized pores arranged regularly and high specific surface area, have attracted considerable attention because of possessing improved functions and applications in chemistry, pharmaceutics, environmental protection and so on. In this study, two biogenic materials, calcium carbonate (CaCO₃), the most widely studied biomineral, and lentinan, showing prominent antitumor activity, are incorporated into the biomineralization process to produce CaCO₃–lentinan microspheres with hierarchical composite pore structure by the hierarchical assembly of nanoparticles. The pore structure analysis indicated that a wormhole mesoporous structure was present in the framework of the CaCO₃–lentinan microspheres and a microporous structure was present in the core part of the mesoporous walls, rendering an unusual hierarchical composite pore structure of CaCO₃. The results revealed that the hierarchical composite pore structure could obviously reduce the release rate and prolong the release time of the anticancer drug, which led to minimization of poisonous side effects and decreased bodily injuries due to the stepwise release of the drug from mesoporous pores to micropores. The component CaCO₃ with pH-sensitivity could controllably release DOX at the acidic tumour site, which minimizes the spread of toxic drugs around the normal tissues while maximizing tumor-directed drug delivery. In particular, the CaCO₃–lentinan microspheres have ideal biocompatibility and biodegradability which are of critical importance for the clinical application. Further investigation also revealed the desirable properties of the CaCO₃–lentinan microspheres for the removal of Congo red (CR) pollutant from waste water, with the maximum removal capacity of 213.2 mg g⁻¹, which will be a great potential material in real applications.