Synthesis of water-soluble chitosan-coated nanoceria with excellent antioxidant properties

Abstract

Nanoceria has been demonstrated as a potential antioxidative nano-drug. However, its short residence time in the body, toxic solvents involved in the synthesis processes, and especially the poor water solubility hinder its potential clinical applications. In this work, water-soluble chitosan-coated nanoceria particles (CNPs) are synthesized by a facile wet chemical route. The molar weight (MW) and concentration of chitosan do not affect the particles' size and the antioxidative activity of the CNPs over a wide range, and the mechanism is explored further. The behavior of CNPs over time and with a change of pH value were also examined. The CNPs reveal excellent antioxidative activity and stability over seven months at room temperature, and importantly, chitosan widens the pH range for the stable existence of water-soluble nanoceria. As a result, including its inherent advantages of wide availability, non-toxicity, biocompatibility and biodegradability, chitosan can also present the nanoceria with good water-solubility without interfering with its antioxidative activity. In other words, chitosan can enlarge the nanoceria stability over a higher pH range. These factors show the advantages of chitosan as a coating layer, promising the further application of nanoceria in biomedical and biotechnological fields.

The Role of Dextran Coatings on the Cytotoxicity Properties of Ceria Nanoparticles Toward Bone Cancer Cells

“…9 Until now, there have been only a few studies on the toxicity properties of nanoceria coated with polymers (dextran, PEG, chitosan, heparin) within the range of 3-20 nm against cancer cells (lung, breast, ovarian and pancreas), healthy cells (dermal fibroblasts, endothelial cells, keratinocytes, human monocytes, and macrophages). 1,2,[11][12][13]15,16,18,[21][22][23] Here, the treatment of osteosarcoma cells with dextran-coated nanoceria was shown for the first time. The role of dextran on the cytotoxicity properties of ceria against osteosarcoma was studied.…”

“…3,7 As a new nanoplatform, cerium oxide (nanoceria) is a promising candidate for improved cancer treatment, drug delivery, catalysis, and sensor applications. 2,[8][9][10][11][12][13] Nanoceria is a critical material that can provide protection to living systems against radiation damage, oxidative stress, and inflammation due to its capability to transition from Ce +3 to Ce +4 . It acts as an antioxidant at physiological pH values.…”

“…9,13,19 Modifying the ceria surface with polymers may increase water solubility of the nanoparticles without changing its redox properties. 9,11 Moreover, polymer surface ceria nanoparticle coatings may increase circulation time in the blood stream. Therefore, there is a need to find an improved delivery medium for nanoceria as a drug delivery platform.…”

“…9,11,15,18 So far, nanoceria has been functionalized with different polymers such as polyethylene glycol (PEG), glucose, heparin, chitosan and dextran. 1,2,11,14,20 Among them, PEG is common polymer for nanoparticle applications as it has significant disadvantages of nondegradability and the ability to avoid immune system clearance. Dextran is a biocompatible, complex polysaccharide that is commonly used as a surface modifier for colloidal nanoparticle synthesis due to its high water solubility.…”

“…Dextran is a biocompatible, complex polysaccharide that is commonly used as a surface modifier for colloidal nanoparticle synthesis due to its high water solubility. 2,11,12,14 It also has pH-dependent antioxidant properties, which makes dextran an indispensable polymer for therapeutic agents. It will selectively protect healthy tissue from free radicals, which can increase during chronic inflammation or upon radiotherapy or chemotherapy.…”