Antioxidant deactivation on graphenic nanocarbon surfaces

Area of Science:

• Materials Science
• Biochemistry
• Nanotechnology

Background:

• Carbon nanomaterials (CNMs) interact with biological systems.
• Antioxidants like glutathione (GSH) are crucial for cellular protection.
• The interaction between CNMs and GSH is not fully understood.

Purpose of the Study:

• To investigate the direct chemical pathway of antioxidant deactivation on CNM surfaces.
• To elucidate the role of dissolved oxygen in this process.
• To explore the implications for nanotoxicity and safe material design.

Main Methods:

• Chemical and electrochemical experiments were conducted.
• Various carbon nanomaterials were tested, including nanotubes, graphene oxide, nanohorns, and carbon black.
• GSH depletion rates were measured and analyzed under different conditions (e.g., nitrogen doping, defect annealing, presence of proteins/surfactants).

Main Results:

• CNMs directly deplete GSH in the presence of dissolved oxygen, forming GSSG.
• Oxygen consumption is significant only when both CNMs and GSH are present.
• Depletion rates vary by CNM type but can be normalized by surface area; rates are influenced by doping, defects, and surface modifiers.

Conclusions:

• A direct catalytic reaction occurs between CNM surfaces and GSH, involving surface-bound oxygen intermediates.
• This interaction may contribute to oxidative stress in nanotoxicity.
• Material properties like surface area and defects influence the reaction, suggesting pathways for designing safer nanomaterials.