Humans are continuously exposed to polymeric materials such as in textiles, car tires and packaging. Unfortunately, their break down products pollute our environment, leading to widespread contamination with micro- and nanoplastics (MNPs). The blood–brain barrier (BBB) is an important biological barrier that protects the brain from harmful substances. In our study we performed short term uptake studies in mice with orally administered polystyrene micro-/nanoparticles (9.55 µm, 1.14 µm, 0.293 µm). We show that nanometer sized particles—but not bigger particles—reach the brain within only 2 h after gavage. To understand the transport mechanism, we performed coarse-grained molecular dynamics simulations on the interaction of DOPC bilayers with a polystyrene nanoparticle in the presence and absence of various coronae. We found that the composition of the biomolecular corona surrounding the plastic particles was critical for passage through the BBB. Cholesterol molecules enhanced the uptake of these contaminants into the membrane of the BBB, whereas the protein model inhibited it. These opposing effects could explain the passive transport of the particles into the brain.

In this paper we show by using static DFT calculations and classical molecular dynamics simulations that the charge transfer between ionic liquid ions plays a major role in the observed discrepancies between the overall mobility of the ions and the observed conductivities of the corresponding ionic liquids, while it also directly suppresses the association of oppositely charged ions, thus the ion pairing. Accordingly, in electrochemical applications of these materials it is important to consider this reduction of the total charges on the ions, which can greatly affect the performance of the given process or device in which the ionic liquid is used. By slightly shifting from the salt-like to a molecular liquid-like system via the decreased charges, the charge transfer also fluidizes the ionic liquid. We believe that this vital information on the molecular level structure of ionic liquids offers a better understanding of these materials, and allows us to improve the a priori design of ionic liquids for any given purpose.

The chemistry of 1,3-dialkylimidazolium-based ionic liquids (ILs) can easily be linked to that of N-heterocyclic carbenes (NHCs) in the presence of sufficiently basic counteranions. B3LYP/6-31+G*, B3LYP/aug-cc-pVTZ and MP2/6-311+G** studies show that increasing the basicity of the anionic component the relative stability of the ion pair and that of the hydrogen bonded complex of the corresponding free acid and NHC itself can be shifted toward the formation of NHC. In the case of the acetate anion, the ion pair and the NHC-acetic acid complex have similar stability. Photoelectron spectroscopic studies show that the vapor of EMIM-acetate is dominated by the NHC-acetic acid complex. The mass spectrum of the same compound shows the presence of both acetic acid and 1-ethyl-3-methylimidazolium-2-ylidene, in agreement with the low pressure during the MS experiment, which facilitates dissociation. The possibility of systematic and simple variation of the NHC content of the ILs facilitates the extension of carbene chemistry in ionic liquids.

Submillimetre-sized plastic particles (microplastics and nanoplastics) of waste origin in the environment have been repeatedly suggested in recent years to have severe impact on living organisms. While the uptake of these materials has been unequivocally evidenced for animals, so far no adverse effects have been observed in the corresponding animal experiments. In this study, we show that nanoplastics are prone to interact with proteins, and this interaction fundamentally changes the functionally crucial secondary structure of these biomolecules, and thereby denaturates them. These results show, for the first time, that the interplay between plastic waste and biological matter can induce significant cellular and thereby ecological damages. Observing these remarkable microscopic level changes highlights the urgent need to extend investigating the effects of these materials through further modelling and molecular biological methods.

Whilst the formation of plastic nanoparticles (nanoplastics) from plastic wastes has been unequivocally evidenced, little is known about the effects of these materials on living organisms at the subcellular or molecular levels. In the present contribution we show through molecular dynamics simulations that polyethylene nanoparticles dissolve in the hydrophobic core of lipid bilayers into a network of disentangled, single polymeric chains. The thereby induced structural and dynamic changes in the bilayer alter vital functions of the cell membrane, which if lacking a mechanism to decompose the polymer chains may result in the death of the cell.