Quantifying Nanoplastic Toxicity Using Gold-Core Polystyrene Nanoparticles: In vivo Evaluation and Human Risk...

Area of Science:

• Environmental Science
• Toxicology
• Materials Science

Background:

• Nanoplastics (NPs) are pervasive environmental pollutants with incompletely understood human health risks.
• Establishing risk thresholds for NP accumulation in human tissues is critical for public health.
• Polystyrene nanoplastics (PS-NPs) are common, necessitating methods to assess their toxicity and bioaccumulation.

Purpose of the Study:

• To validate gold-core polystyrene nanoplastics (AuPS-NPs) as a quantifiable proxy for PS-NPs.
• To evaluate the toxicity and bioaccumulation of NPs at environmentally relevant concentrations.
• To extrapolate findings to assess potential human health implications.

Main Methods:

• Synthesized and characterized AuPS-NPs using TEM and ICP-MS.
• Assessed in vitro cytotoxicity, ROS generation, and mitochondrial depolarization in AGS and Caco-2 cells exposed to AuPS-NPs or PS-NPs.
• Conducted a 98-day in vivo study in mice with AuPS-NPs, analyzing intestinal accumulation, body weight, organ indices, and various biomarkers. Developed a toxicokinetic-toxicodynamic (TK-TD) model.

Main Results:

• AuPS-NPs and PS-NPs exhibited comparable concentration-dependent cytotoxicity in vitro.
• Chronic AuPS-NP exposure in mice led to intestinal accumulation, reduced body weight, altered organ indices, and significant biomarker changes (IL-6, TNF-α, TG, T-CHO, ATP, LDH, MDA, SOD).
• TK-TD modeling determined a human intestinal toxicity threshold of 9.529 × 10^5 particles/kg.

Conclusions:

• AuPS-NPs effectively replicate PS-NPs toxicity, enabling quantitative risk assessment.
• Chronic NP exposure can cause intestinal accumulation and systemic toxicity.
• Regulatory thresholds are needed to mitigate nanoplastic risks to human health.