Uptake and toxicity of polystyrene micro/nanoplastics in gastric cells: Effects of particle size and surface functionalization

Authors: Banerjee, Amrita; Billey, Lloyd; Shelver, Weilin

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2021
Publication Date: 12/31/2021
Citation: Banerjee, A., Billey, L.O., Shelver, W.L. 2021. Uptake and toxicity of polystyrene micro/nanoplastics in gastric cells: Effects of particle size and surface functionalization. PLoS ONE. https://doi.org/10.1371/journal.pone.0260803.
DOI: https://doi.org/10.1371/journal.pone.0260803

Interpretive Summary: Small sized plastics (micro or nanoplastics) have been detected in food and water but their possible adverse effects on tissues after ingestion are poorly understood. For this purpose, we studied the interactions of micro/nanoplastics with stomach cells grown in the laboratory. Micro/nanoplastics of different sizes, surface properties, and doses were tested on cells using exposure periods up to 6 hours. We concluded that the major variables affecting toxicity of the micro/nanoplastics in stomach cells were particle size and surface characteristic; small particle sizes having positive charges on the surface were more detrimental to cellular health than larger sized particles with negative charges on particle surface. These cell-based studies will help to design future studies assessing micro/nanoplastic absorption and distribution in food animals.

Technical Abstract: Toxicity of micro or nanoplastics (MP/NP) in aquatic life is well-documented, however, information about the consequences of exposure to these particles in terrestrial species is scarce. This study was used to evaluate the uptake and/or toxicity of polystyrene MP/NP in human gastric cells, comparing doses, particle sizes (50, 100, 200, 500, 1000 or 5000 nm) and surface functionalization (aminated, carboxylated or non-functionalized). In general, the uptake of 50 nm particles was significantly higher than 1000 nm particles. Among the 50 nm particles, the aminated particles were more avidly taken up by the cells and were cytotoxic at a lower concentration (= 7.5 µg/mL) compared to same sized carboxylated or non-functionalized particles (= 50 µg/mL). High toxicity of 50 nm aminated particles corresponded well with significantly high rates of apoptosis-necrosis induced by these particles (29.2% of total cells) compared to all other particles (= 16.8%). The trend of apoptosis-necrosis induction by aminated particles was 50 > 5000 > 1000 > 500 > 200 > 100 nm. A similar pattern of apoptosis-necrosis was not observed with carboxylated or non-functionalized particles but 50 nm carboxylated or non-functionalized particles induced higher levels of apoptosis-necrosis in the cells compared to 100, 1000 and 5000 nm particles with same surface functionalization. The study demonstrated that the toxicity of MP/NP to gastric cells was dependent on particle size, dose and surface functionalization.