Antioxidant activity of hydrated carboxylated nanodiamonds and its influence on waterγ-radiolysis

Abstract

Water radiolysis involves chemical decomposition of the water molecule into free radicals after exposure to ionizing radiation. These free radicals have deleterious effects on normal cell physiology. Carboxylated nanodiamonds (cNDs) appear to modulate the deleterious effects of γ-irradiation on the pathophysiology of red blood cells (RBCs). In the present work, the antioxidant activity of hydrated cNDs (h-cNDs) on limiting oxidative damage (the water radiolysis effect) by γ-irradiation was confirmed. Our results show that h-cNDs have remarkable free radical scavenging ability and preserve the enzymatic activity of catalase after γ-irradiation. The underlying mechanism through which nanodiamonds exhibit antioxidant activity appears to depend on their colloidal stability. This property of detonation synthesized nanodiamonds is improved after carboxylation, which in turn influences changes in the hydrogen bond strength in water. The observed stability of h-cNDs in water and their antioxidant activity correlates with their protective effect on RBCs against γ-irradiation.

Ionizing Radiation as a Source of Oxidative Stress—The Protective Role of Melatonin and Vitamin D

“…IR, absorbed by tissues and cells, affects their functioning and structure to various extents, depending on the dose and type of radiation [13,14]. In affected cells, ROS are generated mainly through the radiolysis of water molecules (decay by the action of radiation quanta) or the excitation of water molecules and their decay [15,16,39]. IR can also indirectly influence the oxidative-antioxidant homeostasis by damaging different biomolecules [12].…”

“…IR is capable of penetrating the cells of living organisms, where it induces the ionization of both organic and inorganic compounds [13,14]. Due to the high water content in cells, radiolysis of water molecules by IR is the main process contributing to the increased formation of reactive oxygen species (ROS) [15,16]. ROS rapidly react with macromolecules, including proteins, nucleic acids and lipids, leading to cell dysfunction and apoptotic cell death [12].…”

Nanodiamond Particles Reduce Oxidative Stress Induced by Methyl Viologen and High Light in the Green Alga Chlamydomonas reinhardtii

“…They are characterised by small primary particle size (2–10 nm), a large surface area that is highly tunable, and the chemical inertness of the diamond core [ 1 , 2 ]. The tendency of the naturally hydrophobic ND particles to aggregate can be overcome by chemical modifications of the particle surface, which can reduce the grain size, improve their water solubility and biocompatibility, and enrich the physical and chemical properties of NDs [ 1 , 3 , 4 , 5 ]. The distinctive structural and chemical features of the NDs, their easy availability, and minimal toxicity, have enabled the development of numerous nanomaterial applications in biology and medicine, including drug delivery, sensing, imaging, implant coating, cancer treatment, etc.…”

“…The ND surface chemistry is also responsible for the ability of the nanoparticles to promote the reduction of oxygen species [ 23 ]. The antioxidant activity and radical scavenging potential of NDs have been attributed to the numerous functional groups (mainly -OH and -COOH) and abundant C=C bonds on the ND surface [ 4 , 18 , 24 , 25 ]. The degree of UV-mediated lipid peroxidation and consequent aldehyde formation in soybean oil enriched with hydroxylated NDs was lower than in pure oil or oil enriched with non-modified nanoparticles [ 25 ].…”

“…The degree of UV-mediated lipid peroxidation and consequent aldehyde formation in soybean oil enriched with hydroxylated NDs was lower than in pure oil or oil enriched with non-modified nanoparticles [ 25 ]. The radical scavenging ability of hydrated carboxylated NDs was demonstrated in red blood cells and water under γ-irradiation [ 4 ]. Moreover, carboxylated NDs improved cell viability and lowered ROS accumulation in yeast cells under oxidative stress induced by H 2 O 2 addition [ 18 ].…”