Graphite particles induce ROS formation in cell free systems and human cells

Area of Science:

• Environmental Science
• Materials Science
• Toxicology

Background:

• Carbonaceous particulate matter (PM) toxicity is linked to reactive oxygen species (ROS) production.
• PM comprises a core with organic/inorganic coatings, but the role of these coatings in ROS generation is unclear.

Purpose of the Study:

• To investigate if "naked" carbonaceous particles can generate ROS.
• To assess the ROS-producing capability of pure graphite particles in cell-free and in-cell systems.

Main Methods:

• Utilized pure graphite samples of varying sizes produced by ball-milling.
• Employed Raman spectroscopy, electron spin resonance (ESR) with spin trapping, cell viability assays, and fluorescence spectroscopy.

Main Results:

• Pure, "naked" graphitic nanoparticles were found to catalyze electron transfer, producing superoxide ions.
• ROS generation was dependent on particle size, with graphitic platelet edges playing a significant role.
• These nanoparticles reduced cell viability, indicating potential health risks.

Conclusions:

• "Naked" carbonaceous nanoparticles possess inherent ROS-generating capabilities.
• The size and structure (e.g., edges) of graphitic particles influence their ROS production.
• These findings underscore the potential health hazards associated with pure graphitic nanoparticles, independent of external coatings.