BILOCATION - Mechanistic approach for estimating and modeling the bioconcentration potential of charged and ionogenic organic chemicals via in vitro, in vivo and in silico methods

• Applicant: Professor Dr. Stefan Stolte
• Subject Area: Biological and Biomimetic Chemistry ; Analytical Chemistry ; Theoretical Chemistry: Molecules, Materials, Surfaces
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 380298548

• Final Report Year: 2022

Final Report Abstract

Despite numerous attempts to determine the role of the studied ILs in biochemical and physiological processes, their influence on higher organisms was not yet sufficiently understood. The research carried out within the framework of the present project, unveiled new possibilities, not yet described in the literature, for the distribution of ILs in biological systems as a result of their binding interactions with proteins and membrane lipids. Interactions of ILs with HSA do not affect the biological activity of the protein (no structural changes due to IL binding), but can modify (change) its affinity for other types of smallmolecule ligands. The high potential for bioaccumulation of long-chain ILs was confirmed for the first time in an in vivo assay (Hypothesis 1), indicating a high risk of bioaccumulation of these compounds in tissues of aquatic organisms. A clear impact of ion pairing could not be proven (Hypothesis 2), but a multitude of new insights into the mechanisms responsible for tissue specific bioaccumulation by differences in the interactions with transport proteins and membrane lipids were obtained (Hypothesis 3). Finally, suitable in silico methods were used to get deeper insights into interaction mechanisms of ILs with biomolecules in order to predict their partitioning behavior (Hypothesis 4). Major achievements of the project: • New analytical methods have been developed for the determination of trace amounts of ionic liquids (ILs) in aqueous samples and in a complex biological matrix (mussel tissues) using LC-MS/MS (WP 2). • The values of cation and anion binding constants of ILs with blood proteins and membrane lipids were determined (WP 3, 4), while membrane permeation by passive diffusion could be ruled out as a major pathway (WP 6). • It has been shown that in addition to hydrophobicity, the charge and spatial structure of the ion has a significant effect on binding to blood proteins and membrane lipids (WP 3, 4, 8). • It has been shown that the type of counterion and the ionic strength of the solution play an important role in the interactions of ILs with blood proteins (WP 4). • The structural features of the tested ILs determining their affinity for transport proteins, i.e. human serum albumin (HSA) and α-1-acid glycoprotein (AGP) (WP 5, 8), were determined. • The number of ligand-binding sites in each protein (HSA, AGP), the stoichiometry of the bonds formed, the stability constants and the thermodynamic factors determining the stability of IL-protein complexes were determined (WP 5, 8). • The effect of IL binding on protein structure and thermal stability were investigated (WP 5). • Transport proteins were shown to have a significant effect on the concentration and distribution of ionic liquids in the environment (WP 4, WP 5). • Bioconcentration factors (BCFs) were determined for selected ionic liquids via in vivo tests (WP 7), confirming the high bioaccumulation potential of these compounds, what tallies well with the results obtained during in vitro tests, thus demonstrating the reliability of in vitro tests in assessing the bioaccumulation potential of ionic compounds. The project will be the basis of 3 PhD theses and multiple Master theses have been written based on the results. Since the project focused on questions in the field of fundamental research, no direct economic utilization is intended.

Publications

• In vitro methods for predicting the bioconcentration of xenobiotics in aquatic organisms. Science of The Total Environment, 739 (2020, 10), 140261.
  Maculewicz, Jakub; Świacka, Klaudia; Kowalska, Dorota; Stepnowski, Piotr; Stolte, Stefan & Dołżonek, Joanna
  
• Ionic liquids as environmental hazards – Crucial data in view of future PBT and PMT assessment. Journal of Hazardous Materials, 403, 123896.
  Kowalska, Dorota; Maculewicz, Jakub; Stepnowski, Piotr & Dołżonek, Joanna
  
• New bifunctional ionic liquid-based plant systemic acquired resistance (SAR) inducers with an improved environmental hazard profile. Green Chemistry, 23(14), 5138-5149.
  Markiewicz, Marta; Lewandowski, Piotr; Spychalski, Maciej; Kukawka, Rafal; Feder-Kubis, Joanna; Beil, Stephan; Smiglak, Marcin & Stolte, Stefan
  
• Toward the Proactive Design of Sustainable Chemicals: Ionic Liquids as a Prime Example. Chemical Reviews, 121(21), 13132-13173.
  Beil, Stephan; Markiewicz, Marta; Pereira, Cristina Silva; Stepnowski, Piotr; Thöming, Jorg & Stolte, Stefan
  
• Interaction of ionic liquids with human serum albumin in the view of bioconcentration: a preliminary study. Chemical Papers, 76(4), 2405-2417.
  Kowalska, Dorota; Stolte, Stefan; Wyrzykowski, Dariusz; Stepnowski, Piotr & Dołżonek, Joanna
  
• Analysis of imidazolium ionic liquids in biological matrices: A novel procedure for the determination of trace amounts in marine mussels. Talanta, 252, 123790.
  Maculewicz, Jakub; Stepnowski, Piotr; Dołżonek, Joanna & Białk-Bielińska, Anna
  
• Bioconcentration of imidazolium ionic liquids: In vivo evaluation in marine mussels Mytilus trossulus. Science of The Total Environment, 858, 159388.
  Maculewicz, Jakub; Dołżonek, Joanna; Sharma, Lilianna; Białk-Bielińska, Anna; Stepnowski, Piotr & Pazdro, Ksenia