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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Food Animal Metabolism Research » Research » Publications at this Location » Publication #417296
Research Project: Detection and Fate of Environmental Chemical and Biological Residues and their Impact on the Food Supply

Location: Food Animal Metabolism Research

Title: The effects of concentration, duration of exposure, size and surface function of polymethyl methacrylate micro/nanoplastics on human liver cells

Author
item Shelver, Weilin
item Billey, Lloyd
item McGarvey, Amy
item HOSELTON, SCOTT - North Dakota State University
item BANERJEE, AMRITA - Fount Bio

Submitted to: Ecotoxicology and Environmental Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Polymethyl methacrylate (PMMA) plastic has a wide variety of uses in the aircraft, automotive, agriculture, architecture, electronics, medicine, and coatings industries. Because of its widespread use and the large quantity of PMMA produced over several decades, degraded PMMA particles (micro/nanoplastics; MP/NP) are commonly found in the environment, as well as in food, and water. However, information on cellular fate and toxicity of PMMA MP/NP is limited. This study was conducted to determine whether PMMA MP/NP are toxic to liver cells grown in the laboratory. PMMA MP/NP were not toxic to liver cells after 24 hours exposure despite the microplastics being readily absorbed by the cells. However, PMMA MP/NP did induce the release biochemicals indictive of an inflammation response and regulated cell death indicating microplastics induce important biological responses in cell models.

Technical Abstract: Micro/nanoplastics (MP/NP) are ubiquitous environmental contaminants that are detected in diverse matrices. Human exposure to MP/NP have been demonstrated by their presence in numerous body fluids and tissues. Due to the large quantity of production and broad applications, polymethyl methacrylate (PMMA) MP/NP have frequently been measured in surveys of microplastics in the environment. The effects of size, surface charge (aminated, carboxylated or non-functionalized), concentration, and exposure duration of PMMA particles in HepG2 human liver cells were evaluated in this study. Aminated and carboxylated PMMA MP/NP 50 – 5000 nm were not toxic at 0.1 – 100 µg/mL during incubation up to 24 h. The majority of non-modified PMMA MP/NP were also non-cytotoxic. Some sporadic toxicity was measured but it did not follow discernable trends. Confocal images revealed that 50, 100, and 1000 nm PMMA MP/NP were all taken up by HepG2 cells irrespective of surface charge. Particle size significantly effected caspase-3 release (p = 0.0002). Apoptosis was induced in only a small number of cells at 24 and 48 h for 50 nm and 1000 nm MP/NP. From 72 – 120 h, apoptosis increased in a time dependent manner for 50 nm beads at 100 µg/mL for all three surface functionalizations, with amine beads having the highest apoptosis at 120 h (36 %). Production of the pro-inflammatory interleukin-8 (IL-8) increased > 2x when the duration of exposure increased from 4 to 24 h irrespective of particle size, charge, or concentration. Collectively, PMMA MP/NP were not cytotoxic at the concentrations tested, but were able to translocate into HepG2 cells, release caspase-3, induce apoptosis, and produce IL-8 in a time dependent manner.