Are Everyday Plastics Damaging Our DNA? New Study Links Nanoplastics to Genome Instability

We’re surrounded by plastic—but what if the microscopic particles you can’t see are doing the most damage? A new study from the Warsaw University of Life Sciences shows that polystyrene nanoparticles (PNPs), a common type of nanoplastic, interfere with DNA repair mechanisms in human intestinal cells, even at low exposure levels.

“Our findings highlight a sublethal yet dangerous influence of polystyrene nanoplastics on genomic stability,” says lead author Dr. Kamila Maliszewska-Olejniczak.

Key Findings

No direct DNA breaks, but critical repair genes were suppressed
PNPs triggered oxidative stress and disrupted base excision repair (BER) and double-strand break (DSB) repair pathways
Gene expression for key DNA repair proteins like OGG1, LIG1, XRCC1, PARP1, RAD51, and BRCA1 was significantly reduced
Despite low immediate cytotoxicity, clonogenic survival was impaired, indicating long-term damage potential
Cell cycle progression and apoptosis were not significantly affected, suggesting a stealthy genotoxic mechanism

Why This Matters

While short-term toxicity was minimal, the real threat lies in the suppression of DNA repair mechanisms, which could accumulate over time to cause:

Cancer
Accelerated aging
Neurodegenerative diseases
Reproductive toxicity

The study emphasizes that even “safe-looking” exposure to 100 μg/mL PNPs—common in environmental contamination—can damage intestinal epithelial barriers, a first line of defense in the human body.

Experimental Highlights

Model used: Human colon cancer-derived Caco-2 cells
Exposure: 50–1200 μg/mL of 100 nm polystyrene nanoparticles
Assays conducted:
- Trypan Blue & Clonogenic Survival
- Flow cytometry for apoptosis & cell cycle
- ROS (oxidative stress) detection via DCFDA
- DNA damage via Comet Assay & γH2AX marker
- qPCR profiling of 14 DNA Damage Response (DDR) genes

The Bigger Picture

This research adds to growing global concern about nanoplastics in food, water, and air. Unlike microplastics, nanoplastics can:

Penetrate cell membranes
Travel via blood and lymphatic systems
Interact with DNA, proteins, and organelles

Even if they don’t directly cut DNA strands, their long-term genomic effects might manifest as chronic diseases—especially in high-exposure populations or vulnerable individuals.

Reference

Kustra, A., Zając, M., Bednarczyk, P. et al. Exposure to polystyrene nanoparticles leads to dysfunction in DNA repair mechanisms in Caco-2 cells. Biol Res 58, 49 (2025). https://doi.org/10.1186/s40659-025-00629-y