Synthesis of Unstable Vaterite Polymorph of Hollow Calcium Carbonate Nanoparticles and Encapsulation of the Anticancer Drug Cisplatin

Cisplatin is the first generation platinum coordination complex-based anticancer drug developed to treat many different types of cancers. However, cisplatin is associated with numerous side effects. Most of these side effects could be minimized if cisplatin can be encapsulated in a suitable host material for its slow-release only at the cancer cells. In this research, we developed a convenient and simple wet chemical route to synthesize spherical nanoparticles of the vaterite polymorph of calcium carbonate (CCNP) with hollow and porous structures. This is achieved by the soft molecular template based synthesis of vaterite using the template obtained from hydrogen bonded ethylene glycol-water network structures. In these templates, vaterite is synthesized from calcium acetate and sodium hydrogen orthophosphate in the aqueous dispersion. Cisplatin is then encapsulated within these nanoparticles and the materials synthesized are well characterized by several independent analytical methods. The presence of cisplatin in its proper molecular form within the confined environment of vaterite is proven. Taking the advantage of the acidity of cancerous cells, these nanoparticles can be selectively and slowly dissolved only within cancerous cells thus releasing the drug only to the cancerous cells. This would minimize the adverse effects of cisplatin to healthy normal cells while increasing the bioavailability and efficacy of the drug and reducing its dosage.