Layer-by-layer capsules as smart delivery systems of CeO$_2$ nanoparticle-based theranostic agents

Modern methods of cancer treatment include chemotherapy and radiotherapy, but they are often characterized by low efficacy and high toxicity. The effectiveness of cancer therapy is often limited by a lack of effective systems for drug delivery to the tumor site. Cerium oxide nanoparticles are able to act as radioprotectors and as radiosensitizers exhibiting selective toxicity in the tumor microenvironment, providing for their tremendous potential in treating cancer. However, methods for controlled delivery of CeO$_2$ nanoparticles to the tumor have not been investigated nor described yet. In this article, we consider different approaches to the development of new ceria nanoparticle-based theranostic agents. Modification of polyelectrolyte microcapsules with nano-ceria appears to be the most promising method. Our design proposals are based on the synergistic pharmacological action of ceria-based nanomaterials and anticancer pharmaceuticals with the ability to control and visualize their sites of localization.