The Change in Antioxidant Properties of Dextran‐Coated Redox Active Nanoparticles Due to Synergetic Photoreduction–Oxidation

Abstract

Nanoparticles have proven to be novel material with resourceful applications in the field of nanomedicine. Cerium oxide nanoparticles (CNPs) coated with dextran (Dex-CNPs) have been shown to exhibit anticancer properties which is attributed to the change in oxidation states mediated at the oxygen vacancies on the surface of CNPs. In this study, the extreme sensitivity of Dex-CNPs to visible light is demonstrated using room light with a clear indication of synergetic phenomenon of photoreduction of CNPs in the presence of dextran which undergoes simultaneous oxidation. The phenomenon was further confirmed through a systematic time-based expedited study using a high intensity visible light source. The physiochemical changes of Dex-CNPs such as dispersion stability, pH, surface chemistry, antioxidant property, cytotoxicity and the surrounding microenvironment of Dex-CNPs were significantly altered on exposure to visible light, thereby affecting the biological response. Given the significance of nanoparticles which are widely researched nanomaterials, in different fields of nanotechnology and biomedicine, this study demonstrates the significant changes in physiochemical properties of Dex-CNPs with light. The photoreduction of Dex-CNPs affects its bifunctional applications in cancer therapy and thereby this study puts forward the necessity to preserve and sustain their properties through proper storage.

Modulating the Catalytic Activity of Cerium Oxide Nanoparticles with the Anion of the Precursor Salt

“…The chemical properties of CNPs, such as, its surface chemistry regulated by the surface Ce 3+ /Ce 4+ ratio can significantly modulate the bioactivity and antioxidant property of CNPs. 12,15,16 We note that the protein corona formation in the biologically relevant media is regulated by the physical property – dispersion stability as well as by the presence of any chemical entity on CNPs, thereby deciding their cellular internalization. 7, 17 Therefore, it is necessary to thoroughly characterize and analyze the role of chemical entities that are present on the surface of CNPs, after the synthesis and prior to their use in biomedical applications.…”

“…Furthermore, our work has provided evidence that the synthesis method and the chemistry between precursors play an equally important role in determining the physio-chemical characteristics and bioactivity of CNPs. 7, 12, 13 …”

“…7, 17 Therefore, it is necessary to thoroughly characterize and analyze the role of chemical entities that are present on the surface of CNPs, after the synthesis and prior to their use in biomedical applications. 12 It was already established that the high temperature synthesis methods of CNPs resulted in larger particle size, higher size distribution, and greater degree of agglomeration. 13,14 On the other hand, room temperature synthesis techniques, such as -microemulsion and wet chemical, provided a better control on particle size distribution of CNPs and generated CNPs with lower particle size (<10 nm).…”

“…2, 13, 19–21 Additionally, the surface chemistry of CNPs can be modified by changing the pH of the dispersion or by doping. 12 …”

Fulleropyrrolidine-functionalized ceria nanoparticles as a tethered dual nanosystem with improved antioxidant properties

“…It was observed that nanoceria can act both as superoxide dismutase (SOD), by neutralizing superoxide radicals, and catalase (CAT), by promoting the decomposition of hydrogen peroxide into water and oxygen. 44 According to the literature, an increase in Ce 3+ /Ce 4+ ratio induces mimetic properties to Si-Fulp/ceria which are more similar to SOD than CAT. 44 The O 1s spectrum of ( Fig.…”