Biocompatible superparamagnetic sub-micron vaterite particles for thermo-chemotherapy: From controlled design to in vitro anticancer synergism

A promising candidate for the development of controlled and targeted nanoscale drug delivery system but less studied so far is calcium carbonate (CaCO₃) in the form of porous polycrystalline vaterite spheres. Vaterite has been shown to exhibit various beneficial properties such as excellent biocompatibility, high drug loading capacity, and pH-sensitive decomposition under mild conditions. However, fabricating vaterite particles with improved porosity, high surface area and loading a payload into the common synthesis method is still a challenge. Here we report on the synthesis of a highly porous, spherical superparamagnetic vaterite particles (PMVP) of size ∼800 nm encapsulating Iron oxide nanoparticles (IONPs) in a one-step reaction and loaded with DOX molecules through electrostatic attractions and physisorption for cancer thermo-chemotherapy application. The main advantage of the PMVP-DOX is that it can be magnetically targeted into the tumor region and once exposed to the tumor tissues characteristic acidic pH, the PMVP nanoparticle dissociates, releasing the DOX and intelligently converts the pH-triggered drug release into a tumor triggered drug release. Simultaneous application of alternating magnetic field (AMF) generates localized heat of the tumor tissues due to the hyperthermic capability of the IONPs in the PMVP and results in the synergistic tumoricidal activities.