Study Reveals PET Nanoplastics Disrupt Gut Microbes and Damage Human Cells

Nanoplastics — particles smaller than 100 nanometres — are increasingly being detected in food, drinking water, blood, lungs and even the placenta.

A groundbreaking study has delivered the first direct biological evidence that nanoplastics originating from everyday single-use PET bottles can disrupt critical systems in the human body. The findings significantly advance global understanding of how plastic pollution is silently affecting human health far beyond the environment.

Nanoplastics — particles smaller than 100 nanometres — are increasingly being detected in food, drinking water, blood, lungs and even the placenta. Yet, until now, scientists had limited insight into how these particles interact with the living cells and beneficial microbes that sustain human health.

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Why Gut Microbes Matter — and How Nanoplastics Threaten Them

Gut microbes play a foundational role in human well-being, influencing:

• Immune system regulation

• Digestion and metabolic balance

• Protection against pathogens

• Mental health through the gut–brain axis

However, these essential communities are vulnerable to chemical and physical disturbances. The study shows that PET nanoplastics can directly impair Lactobacillus rhamnosus, a key beneficial bacterium widely used in probiotics.

Researchers observed:

• Reduced bacterial growth and colonisation

• Diminished protective functions

• Increased oxidative stress

• Heightened sensitivity to antibiotics

These effects suggest that chronic nanoplastic exposure may contribute to microbial imbalance, known as dysbiosis, which is linked to allergies, obesity, metabolic disorders, autoimmune diseases and mental-health issues.

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Multi-System Investigation Links Environmental Plastics to Human Biology

The study was conducted by scientists at the Institute of Nano Science and Technology (INST), Mohali, under the Department of Science and Technology (DST). Recognising the lack of research on nanoplastics’ direct interaction with living systems, the team designed a multi-system analysis covering three biological models:

1. Gut bacteria (Lactobacillus rhamnosus)

2. Human red blood cells (RBCs)

3. Human epithelial cells (A549 cells)

Researchers first recreated nanoplastics from PET bottles through shredding, dissolving, and synthesizing particles that mimic real-world nanoplastic contamination. These engineered particles were then tested across biological systems to map the risks.

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Disruption of Red Blood Cells: Impaired Blood Stability

At higher concentrations, PET nanoplastics caused:

• Membrane damage

• Hemolytic changes (rupturing of RBCs)

• Altered oxygen-carrying capacity

These findings raise concerns about nanoplastics circulating in human bloodstreams and interacting with vital organs.

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Human Epithelial Cells Show DNA Damage and Inflammatory Responses

Human epithelial cells — which line the respiratory tract, digestive system and skin — showed significant stress under prolonged nanoplastic exposure.

The study recorded:

• DNA damage and genetic instability

• Oxidative stress, a precursor to chronic disease

• Apoptosis, or programmed cell death

• Inflammatory signalling

• Altered energy and nutrient metabolism

These disruptions suggest that long-term exposure could increase risks of inflammation-driven diseases, weakened cellular repair mechanisms, and metabolic disorders.

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Nanoplastics Are Biologically Active, Not Inert

Together, the results show that PET nanoplastics are biologically active contaminants, capable of:

• Interfering with gut microbial health

• Damaging blood cells

• Triggering toxic responses in human tissues

This study reveals a previously hidden link between daily plastic consumption and disruptive biological effects that may accumulate over time.

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Implications for Health, Policy, Industry and the Environment

Published in Nanoscale Advances, the research highlights urgent concerns:

• Nanoplastics are already present in food, water and the human body.

• They may pose health risks at levels much lower than previously assumed.

• New regulatory and industrial standards may be required to limit plastic breakdown.

The findings could shape future policies on:

• Plastic packaging

• Waste management

• Food and water safety

• Microbiome protection

• Environmental health monitoring

Beyond human health, the results may inform fields such as agriculture, soil microbiology, livestock health and ecosystem restoration, where microbial balance is central.