Redox Reactivity of Cerium Oxide Nanoparticles Induces the Formation of Disulfide Bridges in Thiol-Containing Biomolecules

Abstract

The redox state of disulfide bonds is implicated in many redox control systems, such as the cysteine-cystine couple. Among proteins, ubiquitous cysteine-rich metallothioneins possess thiolate metal binding groups susceptible to metal exchange in detoxification processes. CeO2 NPs are commonly used in various industrial applications due to their redox properties. These redox properties that enable dual oxidation states (Ce(IV)/Ce(III)) to exist at their surface may act as oxidants for biomolecules. The interaction among metallothioneins, cysteine, and CeO2 NPs was investigated through various biophysical approaches to shed light on the potential effects of the Ce(4+)/Ce(3+) redox system on the thiol groups of these biomolecules. The possible reaction mechanisms include the formation of a disulfide bridge/Ce(III) complex resulting from the interaction between Ce(IV) and the thiol groups, leading to metal unloading from the MTs, depending on their metal content and cluster type. The formation of stable Ce(3+) disulfide complexes has been demonstrated via their fluorescence properties. This work provides the first evidence of thiol concentration-dependent catalytic oxidation mechanisms between pristine CeO2 NPs and thiol-containing biomolecules.

High‐Energy Resolution Fluorescence Detected X‐Ray Absorption Spectroscopy: A Powerful New Structural Tool in Environmental Biogeochemistry Sciences

“…Such high oxidation power directly or indirectly can create oxidative stress for living organisms and cells. Cerium oxide nanoparticles’ interactions with organisms and biological media have been particularly investigated, such as with human cells (Auffan et al, 2009), biomolecules (Rollin‐Genetet et al, 2015), microorganisms (Zeyons et al, 2009; Ma et al, 2013; Collin et al, 2014), plants (López‐Moreno et al, 2010; Zhang et al, 2012; Hong et al, 2014), mollusks (Tella et al, 2014), and mussels (Garaud et al, 2016). In these studies, the reduction of Ce 4+ to Ce 3+ in CeO 2 nanoparticles was probed by conventional XANES spectroscopy.…”

Antioxidant activity of cerium dioxide nanoparticles and nanorods in scavenging hydroxyl radicals

“…39 Finally, it has been suggested that glutathione could interact with CeNPs and inuence the redox couple of Ce 3+ /Ce 4+ . 40 It is worthy to note that a real physiologic environment is more complicated than SLF. A large number of redox chemistry processes may alter the agglomeration and distribution of CeNPs and relevant materials, 41 which may eventually inuence its properties including $OH scavenging efficiency and SOD-like characteristics.…”

Sensitive and Selective Electrochemical Determination of L‐Cysteine Based on Cerium Oxide Nanofibers Modified Screen Printed Carbon Electrode

“…Comparison of analytical performance of the CeO 2 NFs modified SPCE with other published CysH electrochemical sensors was presented in Table , indicating that the electrochemical performance of the CysH sensor developed in this study is among the best ones . The excellent electrochemical sensing performance of the developed CysH sensor can be attributed to the synergistic effect of following factors: Firstly, the standard potential of the redox couple characteristic of CeO 2 in water is E h (Ce 4+ /Ce 3+ )=+1.15 V, which is higher than the E h of the redox couple of L‐CysH/L‐CyssyC‐L, thus favoring the reaction of L–CysH to L‐CyssyC‐L . Secondly, nanofibrous morphology of CeO 2 endows large specific surface area for electrochemical oxidation of CysH ; Thirdly, highly porous structure of nanofibers allows the free diffusion of analytes, thus minimizing the effect of diffusion on the reaction ; Finally, carbon screen printed working electrode on SPCE possesses excellent stability with very low background current/noise, which benefits the detection of low concentration of CysH.…”

“…These redox properties, which enable dual oxidation states (Ce(IV)/Ce(III)) to co‐exist at the surface, may act as oxidants for biomolecule oxidation (e. g., Ce 4+ +BioRed→Ce 3+ +BioOx) . Recently, a fluorescent sensor was reported for CysH detection due to the formation of detectable fluorescent complexes of Ce 3+ ‐CyssyC when CysH was added to CeO 2 . The overall chemical reaction in fluorescence‐based detection has been proposed as 2Ce 4+ +2CysH→2Ce 3+ +CyssyC+2H + .…”