Breaking Down the Blood-Brain Barrier: Microplastics and Their Impact on Human Health

By Ananya Chopra,

The Lawrenceville School, NJ

Microplastics are tiny plastic particles measuring less than 5mm, that pose a significant environmental and health threat. These particles result from the degradation of larger plastic items and are also intentionally produced for use in cosmetics and synthetic clothing. Humans encounter microplastics through inhalation, ingestion, and direct contact, which may lead to their accumulation in various tissues and organs. Recent research has underscored the capacity of microplastics to penetrate biological barriers, such as the blood-brain barrier (BBB), raising alarms about potential neurotoxic effects and long-term health implications.

The blood-brain barrier is a highly selective, semipermeable layer of cells that prevents solutes in the bloodstream from entering the extracellular fluid of the central nervous system. This barrier safeguards the brain from harmful substances while permitting essential nutrients to pass through. However, studies indicate that both microplastics and nanoplastics (plastics ranging from 1 nm to 1 μm) can breach this barrier, leading to various impacts on the nervous system.

Recent research has confirmed the presence of microplastics in human brain tissues, with concentrations rising over time. A study conducted in early 2025 reported a 50% increase in microplastic levels in human brains from 2016 to 2024. Analysis of postmortem brain samples showed that individuals with dementia had significantly higher microplastic concentrations in their brains compared to those without the condition. This accumulation of microplastics in the brain raises concerns about potential neurological disorders and the worsening of existing conditions.

The research found that microplastics in the bloodstream can lead to cerebral thrombosis by obstructing cells in the capillaries of the brain cortex. This occurs when immune cells engulf microplastics, causing blockages that reduce blood flow and create abnormalities. The extent of this obstruction depends on the size of the particles; specifically, 5-μm plastic particles resulted in more significant cell blockage compared to 2-μm and 0.08-μm particles. The researchers observed that cells tagged with smaller plastic particles faced less obstruction and were cleared more efficiently, with some disappearing within 12 hours.

Image of blood brain barrier sourced from Southwest Research Institute

Additionally, the study indicates that microplastics, acting as foreign substances, can cause neutrophils to polarize, enhancing their interaction with endothelial cells and leading to adhesion. The uptake of larger microplastic particles may alter cell size and characteristics, making it harder for them to navigate through narrowed blood vessels and bends.

This finding that microplastics can cause cell obstruction and cerebral thrombosis changes our perspective on microplastic pollution and its impact on human health. Microplastics have been associated with various health problems, including different types of cancer, respiratory issues from inhalation, cardiovascular problems like strokes and heart attacks, inflammatory bowel disease, and neurological disorders such as dementia, along with cognitive and behavioral changes, particularly during critical developmental stages in children.

The growing evidence regarding the harmful effects of microplastics carries significant implications for both the pharmaceutical and plastic manufacturing industries. The pharmaceutical sector may need to create new therapies and interventions aimed at alleviating the negative impacts of microplastic exposure. This could involve developing medications that help clear microplastics from the body, reduce inflammation, and safeguard against neurological damage. Meanwhile, the plastic manufacturing industry is under increasing pressure to cut back on the production and use of plastics, particularly single-use items, and to explore more sustainable alternatives. This shift could result in greater investment in biodegradable and compostable plastics, as well as advancements in recycling technologies. Additionally, these findings may prompt changes in business practices, with companies that emphasize sustainability and work to minimize their plastic footprint gaining a competitive edge. Consumers are becoming more conscious of the health and environmental consequences of plastics and are increasingly seeking eco-friendly products and packaging.

The discovery of microplastics in the human brain and their potential to cause cell obstruction and cerebral thrombosis underscores the urgent need to tackle microplastic pollution. More research is essential to fully comprehend how microplastics impact human health and to devise effective strategies for reducing exposure and mitigating their harmful effects. The pharmaceutical and plastic manufacturing industries must adjust to this new reality by creating innovative solutions that prioritize sustainability and safeguard public health.

Works Cited

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Haederle, M. (2025, February 3). UNM Researchers Find Alarmingly High Levels of Microplastics in Human Brains – and Concentrations are Growing Over Time. https://hsc.unm.edu/news/2025/02/hsc-newsroom-post-microplastics-human-brains.html 

Huang, H., Hou, J., Li, M., Wei, F., Liao, Y., & Xi, B. (2025). Microplastics in the bloodstream can induce cerebral thrombosis by causing cell obstruction and lead to neurobehavioral abnormalities. Science advances, 11(4), eadr8243. https://doi.org/10.1126/sciadv.adr8243

Kopatz, V., Wen, K., Kovács, T., Keimowitz, A. S., Pichler, V., Widder, J., Vethaak, A. D., Hollóczki, O., & Kenner, L. (2023). Micro- and Nanoplastics Breach the Blood-Brain Barrier (BBB): Biomolecular Corona's Role Revealed. Nanomaterials (Basel, Switzerland), 13(8), 1404. https://doi.org/10.3390/nano13081404 

Mallapaty, S. (2025). Microplastics block blood flow in the brain, mice study reveals. Nature. https://doi.org/10.1038/d41586-025-00178-0

Messier Jones, K., Walker-Franklin, I., Pero Parker, J., & Hoponick Redmon, J. (2024, September 26). Crossing the line: Microplastics breach the Blood-Brain barrier. https://www.rti.org/insights/microplastics-blood-brain-barrier 

Moniuszko, S. (2025, February 5). Study finds high levels of microplastics in human brains that appear to be increasing over time. CBS News. https://www.cbsnews.com/news/microplastics-human-brains-study/