Increased selenium concentration in the synthesis of CdSe magic‐sized quantum dots affects how the brain responds to oxidative stress

Abstract

CdSe magic‐sized quantum dots (MSQDs) have been widely used as fluorescent probes in biological systems due to their excellent optical properties with a broader fluorescence spectrum and stable luminescence in biological media. However, they can be cytotoxic and alter the redox balance depending on the amounts of Cd2+ adsorbed on their surface. Thus, the present study aimed to evaluate whether increases in selenium concentration in the synthesis of CdSe‐MSQDs decrease the oxidative stress caused by Cd2+‐based quantum dots. CdSe‐MSQDs synthesized with different concentrations of selenium were investigated against oxidative stress in the brain of chicken embryos by examining total antioxidant capacity, lipid peroxidation, thiol, and glutathione contents, as well as the activities of glutathione peroxidase, superoxide dismutase (SOD), catalase (CAT), and glutathione reductase. In addition, the vascularization of the chorioallantoic membrane (CAM) analysis was performed. Higher selenium concentrations alter the surface defect levels (decrease free Cd2+) and controlled the oxidative effects of CdSe‐MSQDs by reducing the lipid peroxidation, restoring the glutathione defense system and the antioxidant enzymes SOD and CAT, and maintaining the vascular density of the CAM. The current findings reinforce the study of the effects of the presence of Cd2+ ions on the surface of quantum dots, changing toxicity, and aiming interesting strategies of nanomaterials in biological systems.

Application of quantum dots in brain diseases and their neurotoxic mechanism

“…For example, when the Se concentration is increased in the synthesis process, the Cd 2+ density on the surface of the CdSe QDs will decrease. 129 Furthermore, when exposed to ultraviolet or oxidized, the Cd 2+ release will increase. 130 The core–shell structure can also influence Cd 2+ release from Cd-containing QDs.…”

Selenoprotein P Concentrations in the Cerebrospinal Fluid and Serum of Individuals Affected by Amyotrophic Lateral Sclerosis, Mild Cognitive Impairment and Alzheimer’s Dementia

“…For instance, studies carried out in seleniferous areas in China indicated that peripheral anesthesia, seizures and disturbances such as paralysis, hyperreflexia and polyneuritis can follow chronic selenium intoxication [ 14 , 18 ], while short-term severe overexposure may lead to acute neurotoxicity [ 19 , 20 ]. On the other hand, selenium [ 21 , 22 , 23 ] and selenium-containing nanoparticles [ 24 , 25 , 26 , 27 ] have been suggested by laboratory and animal studies to play a beneficial role in the etiology, prevention and the therapy of neurological diseases, though uncertainties still exist about the overall effects and safety of increasing brain selenium exposure [ 28 , 29 ].…”