Understanding microplastics degradation and detection using bionanotechnology

KEY INSIGHTS 

• DNA can be designed to stick to microplastics: The research showed that certain DNA sequences bind strongly to common microplastics like PVC and polystyrene. By carefully adjusting salt conditions, the team successfully selected DNA “aptamers” that are especially good at attaching to plastic particles.
• Magnetic nanoparticles enable fast separation and breakdown: Simple, unmodified magnetic iron oxide nanoparticles were found to stick to many types of microplastics. This allows microplastics to be quickly separated using magnets, without expensive or complex treatments.
• Magnetic nanoparticles can both capture and help degrade plastics: Once attached, the magnetic nanoparticles can act as catalysts that help break down microplastics under oxidative conditions. This creates a low-cost, dual-purpose approach that combines removal and degradation in a single step.

WHY THIS MATTERS FOR MONITORING AND REMEDIATION

• Better detection tools: Plastic-binding DNA aptamers can be used to develop selective sensors that detect specific types of microplastics in complex environmental samples.
• Faster and lower-cost removal: Magnetic nanoparticles allow microplastics to be quickly separated from water and wastewaterusing simple magnetic methods, reducing time, cost, and technical complexity.
• Pathways to active cleanup: Materials that both capture and help degrade microplastics support new remediation approaches that go beyond monitoring to actively reduce microplastic pollution.

RESEARCH PROCESS 

This research explored how microplastics interact with biological and chemical materials at their surfaces. Because microplastics are small and chemically diverse, understanding what sticks to them is essential for detection, removal, and degradation strategies.

The team studied how DNA binds to different plastic types under varying salt conditions, which led to the discovery of plastic-binding DNA aptamers. In parallel, they demonstrated that bare iron oxide nanoparticles can both attach to microplastics and promote their degradation, offering a simple and scalable approach to microplastics treatment.

These findings open new pathways for detecting, separating, and breaking down microplastics using inexpensive and adaptable materials.

RESEARCHER PROFILES 

Dr. Juewen Liu
Professor of Chemistry, Tier 1 Canada Research Chair in Biosensors & Bionanotechnology, University of Waterloo: Expert in nanomaterials, DNA-based sensors, and microplastics–biomolecule interactions.

Dr. MoMo Zandieh
PhD Researcher (2019–2022), Postdoctoral Fellow (2023–2024), University of Waterloo.
Research focused on microplastics detection using DNA aptamers and catalytic degradation of microplastics.

Key collaborators
John Honek, Yu Zhao, Fereidoun Reza Nezhad, Philippe Van Cappellen, and others contributed to this interdisciplinary work spanning chemistry, materials science, and environmental research.

KEY PUBLICATIONS 

Zandieh, M., Luo, X., Zhao, Y., Feng, C., Liu, J. (2025). Selection of Plastic-Binding DNA Aptamers for Microplastics Detection. Angewandte Chemie International Edition, 64, e202421438.

Zandieh, M., Liu, J. (2022). Removal and Degradation of Microplastics Using the Magnetic and Nanozyme Activities of Bare Iron Oxide Nanoaggregates. Angewandte Chemie International Edition, 61, e202212013.

Zandieh, M. et al. (2024). Catalytic and Biocatalytic Degradation of Microplastics. Exploration, 4, 20230018.