Over the past three decades a growing awareness of environmental protection prompted the development of so-called green and sustainable technologies. Therefore, academic and wider community intensively explores new chemicals and safer, more energy efficient processes based on a rational compromise between economic, social, and environmental requirements. Due to low volatility and stability, ionic liquids emerged as a potential replacement for traditional volatile and harmful organic solvents. Various studies have been carried out to validate the green character of ionic liquids, whereby data published suggest that these compounds, due to their relatively high toxicity and poor biodegradability, could have an extremely negative impact on the environment. This paper presents the current knowledge on the toxicity of ionic liquids, with a special emphasis on the mechanisms by which this group of compounds causes changes in the morphology and physiology of organisms at different organisational levels of the ecosystem.
Cytotoxic Effects of Imidazolium Ionic Liquids on Fish and Human Cell Lines
Ionic liquids bring a promise of a wide range of "green" applications that could replace conventional volatile solvents. However, before these applications become large-scale, their toxicity needs to be investigated in order to predict the impact on human health and environment. In this study we assessed the cytotoxicity of imidazolium ionic liquids (in the concentrations between 0.1 mmol L-1 and 10 mmol L-1) in the ovarian fish cell line CCO and the human tumour cell line HeLa using the MTT cell viability assay. Our results showed that the most cytotoxic ionic liquid was 1-n-butyl-3-methylimidazolium bis(trifluoro methylsulphonyl)imide, [BMIM][Tf2N], followed by 1-n-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4], 1-n-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], and 1,3-dimethylimidazolium hexafluorophosphate [MMIM][PF6]. Generally, the effects were concentration-dependent. They also depended on the type of anion and the n-alkyl chain length. The comparison between the fish CCO and human HeLa cell lines suggests that CCO cells provide a good biological system for initial toxicity testing of ionic liquids that could replace in vivo bioassays.
Electrospun materials are good candidates for the design of tissue regeneration scaffolds as they can simulate the natural surroundings of tissue cells. The study proposes electrospun polycaprolactone (PCL)/cefuroxime (CFU) scaffolds for human cell culture and investigates the influence of the antibiotic content on scaffold morphology, thermal and mechanical properties. The increase in the CFU concentration resulted in the reduction of fiber diameter and number of deformations. It also influenced the reduction of scaffold thermal enthalpies and improved scaffold break strength. With regard to cell growth, the scaffolds showed precedence in greater colonization of the HeLa cells. Finally, these scaffolds showed compatibility with standard human cell lines, and thus they can be used for the repair of damaged tissues.