Cerium
oxide nanoparticles (nanoceria) are regarded as one of the most promising
inorganic antioxidants for biomedical applications. Considering nanoceria
as a potential therapeutic agent, we aimed to develop a robust system
for its intracellular delivery using layer-by-layer polyelectrolyte
microcapsules. We have shown that citrate-stabilized cerium oxide
nanoparticles can be effectively incorporated into the structure of
polyelectrolyte microcapsules made from biodegradable and nonbiodegradable
polymers. The structure and morphology of synthesized microcapsules
were investigated and analyzed using confocal laser scanning microscopy,
scanning electron microscopy, transmission electron microscopy, energy-dispersive
X-ray spectroscopy, and UV/vis spectroscopy. Results of experiments
in vitro on B50 neuroblastoma cells confirmed nanoceria delivery into
the cell while maintaining their antioxidant properties. The results
presented confirm polyelectrolyte microcapsules to be an efficient
intracellular delivery system for therapeutic nanoparticles.
The design of novel, effective drug delivery systems is one of the most promising ways to improve the treatment of socially important diseases. This article reports on an innovative approach to the production of composite microcontainers (microcapsules) bearing advanced protective functions. Cerium oxide (CeO) nanoparticles were incorporated into layer-by-layer polyelectrolyte microcapsules as a protective shell for an encapsulated enzyme (luciferase of Photinus pyralis), preventing its oxidation by hydrogen peroxide, the most abundant type of reactive oxygen species (ROS). The protective effect depends on CeO loading in the shell: at a low concentration, CeO nanoparticles only scavenge ROS, whereas a higher content leads to a decrease in access for both ROS and the substrate to the enzyme in the core. By varying the nanoparticle concentration in the microcapsule, it is possible to control the level of core shielding, from ROS filtering to complete blocking. A comprehensive analysis of microcapsules by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, confocal laser scanning microscopy, and energy-dispersive X-ray spectroscopy techniques was carried out. Composite microcapsules decorated with CeO nanoparticles and encapsulated luciferase were shown to be easily taken up by rat B-50 neuronal cells; they are nontoxic and are able to protect cells from the oxidative stress induced by hydrogen peroxide. The approach demonstrated that the active protection of microencapsulated substances by CeO nanoparticles can be used in the development of new drug delivery and diagnostic systems.
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.
Gd-based complexes are widely used as magnetic resonance imaging (MRI) contrast agents. The safety of previously approved contrast agents is questionable and is being re-assessed. The main causes of concern...
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