Hydroxyl radical production induced by plasma hydrogenated nanodiamonds under X-ray irradiation

Abstract

For the first time, overproduction of hydroxyl radicals (HO˙) induced by plasma hydrogenated detonation nanodiamonds (H-NDs) under X-ray irradiation is reported. Using coumarin (COU) as a fluorescent probe, we reveal a significant increase of 40% of the HO˙ production in the presence of H-NDs (6-100 μg ml) compared with water alone. This effect is related to the negative electron affinity of the hydrogenated nanodiamonds and illustrates the ability of H-NDs to produce reactive oxygen species probably via electron emission in water under X-ray irradiation.

Fluorescence and Physico-Chemical Properties of Hydrogenated Detonation Nanodiamonds

“…The hydrogenation of diamond is of great interest, as it imparts a p-type surface conductivity to bulk diamond samples [7] and also increases the electrical conductivity of detonation nanodiamonds [8]. Hydrogenated detonation nanodiamonds in particular have attracted interest for their unusual interactions with water molecules [9], the creation of free radicals in water [10,11], use as radiosensitizers [12] and their fluorescence properties [13].…”

Using hydrogen isotope incorporation as a tool to unravel the surfaces of hydrogen-treated nanodiamonds

“…According to the literature, this surface treatment also confers: 1) a stability in aqueous solutions with a positive Zeta potential 11 which permits, via an electrostatic grafting, to use DND as a vector of biologics such as small interfering RNA 12 or as seeds for diamond growth by chemical vapor deposition 13 ; 2) modifications in the structure of water molecules surrounding hydrogen-treated DND compared to other surface chemistries according to spectroscopic investigations 14,15 ; 3) a radiosensitisation behavior reported in vitro for radioresistant cancer cells 16 and an overproduction of hydroxyl radicals in water under X-ray irradiation 17 ; 4) the grafting of biomolecules through diverse functionalization strategies 9,18,19 ; 5) specific fluorescence properties 20 . Until now, two different approaches were developed to hydrogenate DND: one involving a hydrogen microwave plasma 9,21 , the other, a thermal annealing under hydrogen [22][23][24] .…”

Gold‐Decorated Nanodiamonds: Powerful Multifunctional Materials for Sensing, Imaging, Diagnostics, and Therapy

“…Hydrogen terminated nanodiamonds, as well as diamonds, exhibit negative electron affinity (NEA), which strongly improves the field emission and the photoemission from the nanodiamond surface. The generation of electrons can be used in cold cathode technology but also in the generation of solvated electrons and radicals for photocatalysis, or reactive oxygen species for in‐vitro treatment of radioresistant cancer cells …”