Surface-Oxidized Nanoplastics Exhibit Increased Interaction with THP-1 Cells

Area of Science:

• Environmental Science
• Toxicology
• Materials Science

Background:

• Microplastics (MPs) and nanoplastics (NPs) pose environmental and health risks.
• Current toxicological studies use unrealistic spherical polystyrene particles.
• Environmentally relevant MPs/NPs have irregular shapes and degraded surfaces.

Purpose of the Study:

• To develop fragmented polyethylene NPs (PE-NPs) mimicking environmental particles.
• To investigate the impact of surface oxidation on NP-cell interactions.
• To provide a realistic experimental framework for NP risk assessment.

Main Methods:

• Synthesized fragmented PE-NPs via precipitation.
• Induced surface oxidation using vacuum UV irradiation to create degraded PE-NPs (dPE-NPs).
• Characterized particle morphology and chemical changes.
• Visualized and quantified cellular interactions using fluorescently labeled NPs and confocal microscopy in THP-1 cells.

Main Results:

• Degraded PE-NPs exhibited irregular morphology and introduced carbonyl groups.
• Surface oxidation altered fluorescence properties.
• dPE-NPs showed significantly enhanced cellular interaction, including uptake and membrane association.
• Oxidation markedly increased the particle-associated area per cell.

Conclusions:

• Surface oxidative modification critically influences NP-cell interactions and uptake.
• Physicochemical properties, especially environmentally induced surface changes, are vital for NP risk assessment.
• This study advances understanding of NP aging effects on biological behavior and health risks.