Replacement of toxic chemical components by non-toxic natural analogs is a popular approach in sustainable projects. The study carried out at Zelinsky Institute of Organic Chemistry (Moscow) has shown that partial replacement of chemical compounds by their natural analogs may surprisingly lead to even more toxic products.
The 21st century has presented us with a new scientific challenge - sustainable development. In a battle for sustainable world, humanity seeks to achieve such noble goals as creating a new generation of superior chemical technologies and materials with complete environmental compatibility.
Chemistry belongs to the sciences for which the concept of non-toxic and waste-free production is of greatest importance. Principles of Green chemistry and Sustainability concept have largely influenced research and development in chemical sciences.
These principles include convenient degradability and minimized toxicity. It is a well-known fact that common chemicals are mainly based on toxic, bio-incompatible substances, which are dangerous for the environment. On the contrary, natural components are biocompatible and have no toxic effects.
Nowadays, chemists undertake numerous efforts to replace toxic substances with corresponding natural analogs, and fortunately, change of just one component sometimes does increase environmental compatibility and reduces harmful impact.
This approach has been used in attempt to create biocompatible ionic liquids. Ionic liquids, also called molten salts, liquid electrolytes, or ionic melts, are salts, which are liquid at temperatures below 100ºC. Spatial directionality and segregated nano-structuring found in ionic liquids provide them with unique properties, one of the most startling of which is the possibility of ‘fine-tuning’: each ionic liquid consists of cation and anion moieties, and by varying them, individually or together, certain properties of the IL can be changed.
Being nonvolatile and nonflammable substances, ionic liquids were believed to become a replacement to traditional volatile and flammable organic solvents, and have found application in such various fields of modern chemistry and technology as organic synthesis, catalysis, electrochemistry, nuclear fuel processing, and others. Originally, ionic liquids were considered as ‘green’ chemicals; however, their biological potential has quickly become evident. Now it is established that ionic liquids may affect life at all levels, from single biomolecules to whole ecosystems.
The study carried out by researchers from Zelinsky Institute of Organic Chemistry evaluates the activity of a recently developed class of amino acid-containing ionic liquids towards cancerous and normal cell cultures. In agreement with the above mentioned sustainability considerations, it was taken for granted that introduction of a natural component (i.e. amino acid) into the ionic liquid would decrease its toxicity and lead to more environmentally friendly chemical derivative.
The researchers replaced the cation and anion in the common ionic liquid [BMIM][BF4] with the natural amino acid Valine to obtain two modified ionic liquids - [BMIM][Val] (bearing Valine as an anion) and [Val-OMe][BF4] (bearing valine as a cation). As one may expect, [BMIM][Val] turned out to be less toxic than the original compound [BMIM][BF4] (see Figure 1). However, [Val-OMe][BF4] demonstrated unexpectedly high toxicity. Surprisingly, replacement of a chemical component [BMIM]+ with a natural cation based on Valine gave noticeably more toxic ionic product.
The authors tested a series of common and amino acid-based ILs and showed that ionic liquids containing anions or cations based on the amino acids Glycine, Alanine, or Valine generally demonstrate cytotoxicity higher or comparable to that of conventional imidazolium-based ILs with inorganic or small organic anions (Figure 2). The authors observed increased toxicity for several ionic systems after incorporation of natural amino acid fragments.
A possible mechanism of action of such amino acid containing ionic liquids involves interactions with membrane transporter proteins employed by cells for amino acid intake. A harmless amino acid, being a part of ionic liquid, helps a biologically active/toxic moiety to enter the cell, where it causes apoptosis, or the programmed cell death. Although the original goal on making a non-toxic ionic liquid was not achieved, these findings suggest potential application of amino acid containing ionic liquids in biology and medicine for targeted drug delivery utilizing tunable properties of ionic liquids.
As Prof. Ananikov commented: "Toxicity and eco-activity of ionic liquids is now a well-addressed topic. As we recently reviewed, achieving superior chemical properties, as well as simultaneously holding environmental compatibility, is a very complicated, but unavoidable direction for task-specific optimization."
To summarize, replacement of toxic chemical components by non-toxic and biocompatible natural analogs is one of the most popular approaches in sustainable projects. The study carried out at Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences (Moscow) has shown that partial replacement of chemical compounds by their natural analogs may surprisingly lead to even more toxic products. The article published in Toxicology Research describes increased toxicity of ionic liquids after incorporation of amino acid residues.
The toxicological study: "Unexpected increase of toxicity of amino acid-containing ionic liquids", by Egorova K. S., Seitkalieva M. M., Posvyatenko A. V., and Ananikov V. P. has been published in Toxicology Research (Royal Society of Chemistry).
Reference: Toxicol. Res., 2015, 4, 152-159, DOI: 10.1039/C4TX00079J
On-line link: http://dx.doi.org/10.1039/C4TX00079J
The review on task-specific optimization mentioned in the comment:
Egorova K. S., Ananikov V. P., "Toxicity of Ionic Liquids: Eco(cyto)activity as Complicated, but Unavoidable Parameter for Task-Specific Optimization", ChemSusChem, 2014, 7, 336-360. DOI: 10.1002/cssc.201300459; On-line link: http://dx.doi.org/10.1002/cssc.201300459
Ananikov Laboratory | ResearchSEA
Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg
Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences
16.11.2018 | Physics and Astronomy