Nanoplastics are typically defined as plastic particles smaller than 1000 nanometers. These particles are increasingly being detected in human tissues: they can bypass biological barriers, accumulate in organs, and may influence health in ways researchers are only beginning to understand.1
This article outlines five key evidence-based findings on how nanoplastics interact with the human body.
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Nanoplastics Have Been Found in Human Brain Tissue
Recent research has confirmed that nanoplastics can cross cellular barriers, including the blood-brain barrier (a highly selective, semi-permeable membrane that protects the brain from harmful substances).
A 2025 study published in Nature Medicine by Nihart et al. detected nanoplastics, particularly polyethylene (PE), in human brain, liver, and kidney tissues, with the highest concentrations found in the brain.2
The study analyzed post-mortem samples collected between 2016 and 2024 using a combination of advanced detection methods, including Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS). Results showed a significant increase in nanoplastic concentrations over time, particularly in brain tissue, pointing to increased environmental exposure.
The highest levels were observed in individuals with diagnosed neurodegenerative conditions, such as Alzheimer’s disease and vascular dementia. In these samples, nanoplastics were detected near cerebrovascular walls and within immune cells, suggesting possible involvement in inflammatory processes or impaired waste clearance.
These findings align with previous animal studies, which have shown that nanoplastics can induce inflammation, oxidative stress, and behavioral changes following exposure.
While the causal relationship between nanoplastic exposure and neurological disease remains under investigation, these findings highlight the potential for long-term accumulation in sensitive tissues and reinforce the need for further toxicological research.
Pathways of Nanoplastics Exposure: Inhalation, Ingestion, and Skin Contact
Human exposure to nanoplastics occurs primarily through food, drinking water, airborne particles, and dust. These particles have been detected in bottled water, seafood, table salt, and household environments.
Due to their small size, nanoplastics can be inhaled and deposited deep in the lungs or absorbed through the gastrointestinal tract following ingestion.
Recent research by Menichetti et al. has also demonstrated that nanoplastics can penetrate the skin, particularly when the skin barrier is compromised by inflammation, aging, injury, or chemical exposure. The degree of skin penetration is influenced by the size, shape, and surface chemistry of the nanoparticle.3
Particles with hydrophilic surface modifications, such as PEGylation or the addition of carboxyl (–COOH) or amine (–NH₂) groups, have shown greater skin permeability. These coatings reduce binding to skin proteins and improve transdermal transport through the stratum corneum.
Experimental models have further shown that polystyrene nanoplastics, especially those ≤100 nm, can accumulate in keratinocytes and fibroblasts, potentially disrupting cell proliferation and initiating immune responses.3,4
Nanoplastics Can Accumulate in Organs and Vascular Tissue
Nanoplastics have been detected in several vital organs, including the liver, spleen, heart, and placenta. Once internalized, they are not readily excreted. Their small size and physicochemical stability allow them to persist in tissues for extended periods.
A 2024 study by Marfella et al., published in the New England Journal of Medicine, investigated the presence of plastic particles in carotid artery plaques from 304 patients undergoing endarterectomy.
The findings revealed that 58.4 % of patients had detectable levels of polyethylene, while 12.1 % had polyvinyl chloride embedded in their plaques. These materials, primarily under 1 micron in size, were confirmed using pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) and electron microscopy.5
Importantly, the presence of nanoplastics in arterial plaques was associated with a significantly increased risk of adverse cardiovascular events. Over a 34-month follow-up, individuals with detectable plastic particles faced a more than fourfold increased risk of heart attack, stroke, or death (adjusted hazard ratio: 4.53; 95 % CI: 2.00–10.27; P < 0.001).5
These findings suggest that nanoplastics may contribute to vascular inflammation or destabilize arterial plaques, raising concerns about the long-term cardiovascular impacts of plastic exposure.
How plastic is accumulating inside our cells
Nanoplastics Can Trigger Inflammation and Cellular Stress Responses
Toxicological studies have shown that nanoplastics can provoke immune responses once internalized by the body. Recognized as foreign material, these particles may trigger inflammation and oxidative stress at the cellular level.
While often subtle, these responses may become chronic, raising concern about links to long-term conditions such as cardiovascular disease and cancer.
For example, Mahmud et al. demonstrated that nanoplastics induce significant production of reactive oxygen species (ROS) across various human and animal cell types, including those from the kidney, liver, lungs, intestines, and immune system.
ROS production is influenced by both the physical characteristics of the particles and the chemical additives or surface contaminants they carry. Sustained oxidative stress can damage mitochondria, impair protein and DNA integrity, and lead to long-term cellular dysfunction.6
Weber et al. further observed that nanoplastics consistently trigger chronic inflammatory responses in multiple human cell types, including those derived from the vascular system, kidneys, intestines, and lungs. This immune activation is characterized by increased production of pro-inflammatory cytokines such as IL-6, IL-1β, TNF-α, and IL-8.
The inflammatory cascade is thought to be driven by oxidative stress, lysosomal damage, and activation of immune cells such as macrophages and microglia. These patterns resemble mechanisms implicated in chronic inflammatory diseases.7
Nanoplastics are also linked to cellular senescence, a permanent cell cycle arrest commonly associated with aging. Elevated levels of senescence markers such as p16, p21, and β-galactosidase have been observed following nanoplastic exposure. These changes are closely tied to mitochondrial dysfunction, oxidative DNA damage, impaired autophagy, and epigenetic disruption.8
Over time, such cellular effects may lead to cumulative tissue damage, reduced regenerative capacity, and an increased risk of age-related conditions, including neurodegeneration and cardiovascular disease.
Detection and Biomonitoring Are Improving, But Gaps Remain
Until recently, it was nearly impossible to track nanoplastics in human tissue. However, advances in analytical techniques, such as pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS), Raman spectroscopy, and electron microscopy, enable more accurate identification and quantification of nanoplastics in biological samples.
These tools support real-time exposure assessments, biomarker development, and investigations into plastic accumulation in human tissues.9
A recent study by Shao et al. highlighted widespread human exposure to nanoplastics, detecting them in blood, breast milk, and placental tissue. The findings underscore the growing concern over nanoplastics as emerging environmental contaminants with potential health implications.
Over 16,000 chemicals are used in plastic manufacturing, many of which have not been adequately assessed for toxicity. This raises questions about their possible links to endocrine disruption, neurotoxicity, and carcinogenicity.
One key challenge remains standardization. Despite improved detection methods, there are still no consistent protocols for sample collection, processing, and reporting.9 Quality assurance and quality control (QA/QC) are also essential to avoid contamination from plastic-based lab equipment, which is a frequent source of interference in analytical workflows.
Future research will benefit from the development of high-throughput, automated detection platforms, as well as the integration of machine learning to support large-scale biomonitoring. Prioritizing toxicological studies on the most commonly detected nanoplastics will also be important for identifying reliable biomarkers and guiding regulatory action.
Why It Matters
The evidence is mounting: nanoplastics are not just an environmental headache; they are a potential public health issue.
While the long-term effects are still being studied, the ability of these particles to enter cells, accumulate in organs, and disrupt biological systems is enough to demand serious attention. The WHO and other global health bodies are now calling for more research and policy to address this emerging threat.
As science continues to uncover the hidden impacts of nanoplastics, one thing is clear: what we cannot see can hurt us.
To explore current testing approaches and evaluation techniques, visit:
How to Assess Nanotoxicity: Key Methods and Protocols
References and Further Readings
1. Yee, M. S.-L.; Hii, L.-W.; Looi, C. K.; Lim, W.-M.; Wong, S.-F.; Kok, Y.-Y.; Tan, B.-K.; Wong, C.-Y.; Leong, C.-O., Impact of Microplastics and Nanoplastics on Human Health. Nanomaterials 2021, 11, 496. https://www.mdpi.com/2079-4991/11/2/496
2. Nihart, A. J.; Garcia, M. A.; El Hayek, E.; Liu, R.; Olewine, M.; Kingston, J. D.; Castillo, E. F.; Gullapalli, R. R.; Howard, T.; Bleske, B., Bioaccumulation of Microplastics in Decedent Human Brains. Nature Medicine 2025, 1-6. https://www.nature.com/articles/s41591-024-03453-1
3. Menichetti, A.; Mordini, D.; Montalti, M., Penetration of Microplastics and Nanoparticles through Skin: Effects of Size, Shape, and Surface Chemistry. Journal of Xenobiotics 2025, 15, 6. https://www.mdpi.com/2039-4713/15/1/6
4. Cheng, S.; Hu, J.; Guo, C.; Ye, Z.; Shang, Y.; Lian, C.; Liu, H., The Effects of Size and Surface Functionalization of Polystyrene Nanoplastics on Stratum Corneum Model Membranes: An Experimental and Computational Study. Journal of Colloid and Interface Science 2023, 638, 778-787. https://doi.org/10.1016/j.jcis.2023.02.008
5. Marfella, R.; Prattichizzo, F.; Sardu, C.; Fulgenzi, G.; Graciotti, L.; Spadoni, T.; D’Onofrio, N.; Scisciola, L.; La Grotta, R.; Frigé, C., Microplastics and Nanoplastics in Atheromas and Cardiovascular Events. New England Journal of Medicine 2024, 390, 900-910. https://www.nejm.org/doi/full/10.1056/NEJMoa2309822
6. Mahmud, F.; Sarker, D. B.; Jocelyn, J. A.; Sang, Q.-X. A., Molecular and Cellular Effects of Microplastics and Nanoplastics: Focus on Inflammation and Senescence. Cells 2024, 13, 1788. https://www.mdpi.com/2073-4409/13/21/1788
7. Weber, A.; Schwiebs, A.; Solhaug, H.; Stenvik, J.; Nilsen, A. M.; Wagner, M.; Relja, B.; Radeke, H. H., Nanoplastics Affect the Inflammatory Cytokine Release by Primary Human Monocytes and Dendritic Cells. Environment international 2022, 163, 107173. https://www.sciencedirect.com/science/article/pii/S016041202200099X
8. Wu, D.; Zhang, M.; Bao, T. T.; Lan, H., Long-Term Exposure to Polystyrene Microplastics Triggers Premature Testicular Aging. Particle and fibre toxicology 2023, 20, 35. https://link.springer.com/article/10.1186/s12989-023-00546-6
9. Shao, K.; Zou, R.; Zhang, Z.; Mandemaker, L. D.; Timbie, S.; Smith Jr, R. D.; Durkin, A. M.; Dusza, H. M.; Meirer, F.; Weckhuysen, B. M., Advancements in Assays for Micro-and Nanoplastic Detection: Paving the Way for Biomonitoring and Exposomics Studies. Annual Review of Pharmacology and Toxicology 2024, 65. https://doi.org/10.1146/annurev-pharmtox-030424-112828
