Nanoplastic Pollution of Human Bronchoalveolar Lavage Probed Based on Tip-Enhanced Raman Scattering

Area of Science:

• Environmental Science
• Analytical Chemistry
• Nanotechnology

Background:

• Microplastics (MPs) are plastic particles (1 μm–5 mm).
• Nanoplastics (NPs) (<1 μm) are challenging to analyze with conventional Raman spectroscopy due to signal limitations.
• Tip-enhanced Raman scattering (TERS) offers enhanced sensitivity for nanoscale chemical analysis.

Purpose of the Study:

• To analyze nanoplastics (NPs) in human bronchoalveolar lavage (BAL) fluid using TERS.
• To develop and validate a nanoscale TERS imaging procedure for biological samples.
• To compare TERS findings with conventional Raman microscopy.

Main Methods:

• Developed a sub-sampling procedure for nanoscale TERS imaging on an SiO2/Si substrate.
• Investigated the coffee-ring effect on NP distribution.
• Utilized atomic force microscope (AFM) with a plasmonic tip for signal enhancement.
• Compared TERS data with confocal Raman microscopy.

Main Results:

• TERS successfully detected and analyzed NPs in human BAL fluid.
• Identified plastic, pigments, and mineral particles, linking NPs to MPs.
• Quantified total nanoparticle density in BAL at ~50 billion particles/L, with NPs being predominant.
• Observed similar particle types between TERS and confocal Raman microscopy.

Conclusions:

• TERS is a powerful tool for analyzing NPs in human biological fluids.
• The study provides crucial data on NP prevalence in lung lavage fluid.
• TERS methodology can be applied to other human samples to investigate NP health impacts.