New method reveals how nanoplastics interact with human immune cells in blood

Oct 30, 2024

(Overview of Nanowerk) Plastic pollution has emerged as one of the most pressing environmental problems of our time, with approximately 400 million tons of plastic waste produced annually worldwide. Of particular concern are nanoplastics – microscopic plastic particles smaller than one micrometer that can enter living organisms through various routes such as air, water and food. Until now, scientists have struggled to understand exactly how these tiny particles interact with human immune cells and what risks they might pose to human health. The main obstacle has been the difficulty of tracking these particles once they enter the bloodstream and determining their precise effects on different types of immune cells.

Traditional methods used to study nanoplastic interactions with human cells have relied on fluorescent labeling or imaging techniques, but these approaches have significant limitations. While fluorescent markers can separate from plastic particles, leading to false results, traditional imaging methods cannot track particles simultaneously and observe their effects on multiple cell types. Additionally, previous studies have primarily used laboratory cell lines rather than actual human blood cells, limiting their relevance to real-world exposure scenarios.

A new study has been published Advanced Materials (“Nanoplastics: Immune Effect, Detection, and Internalization After Exposure to Human Blood by Single Cell Mass Cytometry”Research by researchers from the University of Padua and several international collaborators offers an innovative approach to monitoring and studying nanoplastic particles in human blood. The research team used a special technique called single-cell mass cytometry (CyTOF) combined with palladium-doped polystyrene nanoparticles to observe how these materials interact with human immune cells in previously unseen detail. Workflow of the study. Study workflow demonstrating biological characterization of 50 to 200 nm polystyrene nanoplastics (PS NPs) and metal-doped polystyrene nanoplastics (PS-Pd NP shell) on peripheral blood mononuclear cells and whole blood. The effect of NP on up to 30 types of human blood immune cells was evaluated by single-cell mass cytometry (CyTOF) ex vivo. Evaluation of cell viability, cell functionality, and NP uptake by CyTOF was performed. (Image: copied from DOI:10.1002/adma.202413413, CC BY) (click on the image to enlarge)

Researchers have developed a method to track plastic particles by adding palladium atoms into them, allowing sensitive detection via mass spectrometry. This technique allowed them to simultaneously track the location of the particles and measure their effects on 37 different subpopulations of immune cells in human blood; This was a level of detail previously impossible to achieve.

The study revealed a clear size-dependent effect of nanoplastic particles on immune cells. Larger particles (200 nanometer) showed significantly stronger effects on cell functionality compared to smaller ones (50–100 nanometers). Classical monocytes showed the highest uptake of particles, followed by myeloid dendritic cells, plasmacytoid dendritic cells, and memory B cells. The research team also observed significant particle internalization in various T cell subsets.

Of particular note was the particles’ ability to trigger specific inflammatory responses. The study documented increased production of several important inflammatory signaling molecules, including interleukin-4 (IL-4), tumor necrosis factor-alpha (TNF-α), and granulocyte-macrophage colony-stimulating factor (GM-CSF). These cytokines were elevated in multiple immune cell types, with T helper cells, B cells, natural killer cells, and dendritic cells showing the most prominent responses.

When tested in mice, particles accumulated primarily in the liver and spleen, and specific immune cells in these organs showed high levels of particle uptake. In the liver, conventional dendritic cells and macrophages exhibited particularly high levels of particle internalization; Up to 30% of monocytes and granulocytes showed evidence of particle uptake.

The research represents a significant advance in our ability to study the health effects of plastic pollution. By combining innovative particle tracking methods with advanced immune cell analysis, the team has created a powerful new tool for understanding how nanoplastics interact with the human immune system. This approach overcomes many technical limitations that have hindered previous work in this area.

The implications of this study extend beyond understanding plastic pollution. The developed methods can be applied to study other types of particles and their effects on human health, potentially improving our understanding of various environmental exposures and their effects on health. The technique’s ability to simultaneously track particles and measure their effects on multiple cell types provides a more complete picture of potential health effects than previously possible.

With

Michael
Berger

– Michael is the author of three books from the Royal Society of Chemistry:
Nano-Society: Pushing the Boundaries of Technology,
Nanotechnology: The Future Is Too SmallAnd
Nanoengineering: Skills and Tools That Make Technology Invisible
Copyright ©




Nanowerk LLC