Plastic Analysis with a Plasmonic Nano-Gold Sensor Coated with Plastic-Binding Peptides

Area of Science:

• Environmental Science
• Analytical Chemistry
• Biotechnology

Background:

• Microplastic contamination (<1 µm) poses a significant health risk to aquatic and terrestrial organisms.
• Accurate detection of diverse plastic types in biological samples is crucial for environmental monitoring.

Purpose of the Study:

• To develop and validate a novel sensor using plastic-binding peptides and gold nanoparticles for detecting microplastics.
• To assess the presence and levels of microplastics in freshwater mussels exposed to different environmental conditions.

Main Methods:

• Selection of plastic-binding peptides for polyethylene (PE), PET, polypropylene (PP), and polystyrene (PS).
• Utilizing a plasmonic nano-gold sensor with these peptides to detect target plastics.
• Application of a multiple regression model to correct for cross-reactivity between plastic types.
• In-situ testing using caged freshwater mussels at various pollution sites.

Main Results:

• The nano-gold peptide sensor demonstrated high specificity and sensitivity for target plastics, with measurable signals indicating plastic presence.
• Partial cross-reactivity was observed, which was successfully corrected using a regression model.
• Mussels from rainfall overflow and urban downstream sites showed higher concentrations of PP, PE, and PET compared to those near a treated municipal effluent site.

Conclusions:

• Plastic-binding peptides coupled with plasmonic nano-gold sensors offer a rapid, inexpensive, and effective screening tool for microplastic detection in biological samples.
• Wastewater treatment processes appear to partially reduce the load of plastic nanoparticles in effluents.
• The study provides valuable insights into microplastic accumulation in aquatic organisms and the efficacy of pollution control measures.