Cellular uptake of polystyrene nanoplastics with surface Functionalization: An AIE-based quantitative approach

Area of Science:

• Environmental Science
• Toxicology
• Materials Science

Background:

• Nanoplastics (NPs) are increasingly prevalent environmental contaminants.
• Existing toxicity studies often overlook environmental weathering effects on NP surface chemistry.
• Cellular uptake is a critical factor in assessing NP bioaccumulation and toxicity.

Purpose of the Study:

• To quantify the effect of surface functionalization on nanoplastic cellular uptake using an aggregation-induced emission (AIE) approach.
• To investigate how carboxyl (-COOH) and amino (-NH2) functional groups influence nanoplastic interactions with cells.
• To evaluate the toxicity of functionalized nanoplastics in a relevant biological model.

Main Methods:

• Synthesis of carboxylated and aminated polystyrene nanoplastics (PSNPs) via emulsion polymerization.
• Incorporation of an AIE fluorescent label for precise quantification and differentiation from biomolecules.
• Utilizing mouse macrophages (RAW264.7) as a model system for cellular uptake and toxicity studies.
• Employing quantitative fluorescence analysis and flow cytometry for data acquisition.

Main Results:

• Surface carboxylation significantly enhanced cellular uptake of PSNPs compared to pristine PSNPs.
• PSNP-COOH demonstrated the highest cellular uptake among the tested nanoplastics.
• PSNP-COOH also exhibited the most pronounced effects on macrophage toxicity.
• AIE-based approach enabled accurate quantification and differentiation of NPs.

Conclusions:

• Surface functionalization plays a crucial role in nanoplastic cellular uptake and subsequent toxicity.
• Carboxylated nanoplastics pose a higher biological risk due to enhanced cellular uptake.
• The AIE-based method provides a valuable tool for environmentally relevant nanoplastic toxicity assessment.
• Considering surface modifications is essential for accurate evaluation of nanoplastic exposure risks.