Cellular interactions with polystyrene nanoplastics—The role of particle size and protein corona

Abstract

Plastic waste is ubiquitously spread across the world and its smaller analogs-microplastics and nanoplastics-raise particular health concerns. While biological impacts of microplastics and nanoplastics have been actively studied, the chemical and biological bases for the adverse effects are sought after. This work explores contributory factors by combining results from in vitro and model mammalian membrane experimentation to assess the outcome of cell/nanoplastic interactions in molecular detail, inspecting the individual contribution of nanoplastics and different types of protein coronae. The in vitro study showed mild cytotoxicity and cellular uptake of polystyrene (PS) nanoplastics, with no clear trend based on nanoplastic size (20 and 200 nm) or surface charge. In contrast, a nanoplastic size-dependency on bilayer disruption was observed in the model system. This suggests that membrane disruption resulting from direct interaction with PS nanoplastics has little correlation with cytotoxicity. Furthermore, the level of bilayer disruption was found to be limited to the hydrophilic headgroup, indicating that transmembrane diffusion was an unlikely pathway for cellular uptake-endocytosis is the viable mechanism. In rare cases, small PS nanoplastics (20 nm) were found in the vicinity of chromosomes without a nuclear membrane surrounding them; however, this was not observed for larger PS nanoplastics (200 nm). We hypothesize that the nanoplastics can interact with chromosomes prior to nuclear membrane formation. Overall, precoating PS particles with protein coronae reduced the cytotoxicity, irrespective of the corona type. When comparing the two types, the extent of reduction was more apparent with soft than hard corona.

Nanoplastic Toxicity: Insights and Challenges from Experimental Model Systems

“…These results are contrary to the results from Kihara et al, where precoated PS NPs (20 nm) decreased cytotoxic effects in A549 cells, independent from the type of protein corona (positive lysozymes or negatively charged human serum albumin proteins). [154] However, this is in line what is observed from C. elegans experiments comparing particle effect with and without eco-corona. [155] As already mentioned in Chapter 3, an ecocorona is encapsulating the particles through the association of organic molecules in the environment, like dissolved organic matter.…”

Nanoplastics induce more severe apoptosis through mitochondrial damage in Caco-2 cells compared to sub-micron plastics

“…The length and fragment content of the tail is proportionate to the degree of DNA damage. Su ciently small PS can make a direct contact with the nuclear membrane, which can damage DNA and disturb DNA replication [53]. Moreover, indirectly, DNA damage caused by the large amount of cytoplasmic ROS generated by PS through oxidative stress [54].…”

Tailor-Made Protein Corona Formation on Polystyrene Microparticles and its Effect on Epithelial Cell Uptake

“…So far, protein corona formation has been mainly investigated in the case of nanoparticles (i.e., diameter < 0.1 μm 24 ). 14,16,19,23,25,26 Besides particle size, 27,28 surface modifications like carboxy or amine groups influence protein corona formation and composition. 14,16,29−31 Noteworthy, it has been shown that protein corona composition can influence the cellular uptake of particles.…”

“…In particular, protein–protein interactions play a more important role than those described by Vroman. , Hence, it can be stated that the mechanism of protein corona formation is still not fully understood. So far, protein corona formation has been mainly investigated in the case of nanoparticles (i.e., diameter < 0.1 μm). ,,,,, Besides particle size, , surface modifications like carboxy or amine groups influence protein corona formation and composition. ,,− Noteworthy, it has been shown that protein corona composition can influence the cellular uptake of particles. In the case of a protein corona containing immunoglobulins and complement factors from human plasma on pristine particles, a stealth effect was observed where cells did not recognize the particles anymore, but this is dependent on cell type.…”