Nanomaterials

Nanotechnology

Organic chemistry

Enzyme

Oxidative stress

Darkness

Superoxide

Reactive oxygen species

Biology

Biophysics

Radical

Nuclear chemistry

Engineering

Physical chemistry

Nanoparticle

Aqueous solution

Chemistry

Materials science

Hydroxyl radical

Botany

Chemical engineering

Oxygen

Biochemistry

Photochemistry

The Journal of Physical Chemistry

Nanomaterials, which promote the generation of reactive oxygen species (ROS) and precipitate the onset of oxidative stress responsible for the development of a variety of adverse conditions, have a great prospect for various nanomedicine applications. In this paper, for the first time, we report the pro-oxidant activity of GdYVO₄:Eu³⁺ and GdVO₄:Eu³⁺ nanoparticles (NPs) in water solutions without any external stimuli (in the darkness). This dark pro-oxidant activity is shown to be associated with superoxide (O₂•–) and hydroxyl radical (•OH) generation and is dependent on the size of NPs and, consequently, the concentration of surface defects, such as oxygen vacancies VO. For small 2 nm GdYVO₄:Eu³⁺ NPs, strong O₂•– and •OH radical production has been revealed, whereas for larger GdVO₄:Eu³⁺ NPs, low level of O₂•– and negligible level of •OH radical production have been detected during the sample storage in the darkness. The possible mechanisms of the dark ROS generation in ReVO₄:Eu³⁺ NPs are considered.

Dark Reactive Oxygen Species Generation in ReVO₄:Eu³⁺ (Re = Gd, Y) Nanoparticles in Aqueous Solutions