Presence Of ILs Research Articles

Effects of imidazolium-based ionic liquids on the elasticity of DNA revealed by magnetic tweezers

The functions of DNA are related to its mechanical properties, including elasticity and conformational transitions. Ionic liquids, known as green solvents, are used for DNA separation and as a solvent medium for long-term DNA storage. This paper elucidated DNA interaction mechanisms with two imidazolium-based ionic liquids: 1-butyl-3-methylimi-dazolium chloride ([bmim]Cl) and 1-octyl-3-methylimidazolium chloride ([omim]Cl), via magnetic tweezers, bulk techniques and molecular dynamic simulation (MD). By stretching and twisting individual DNA molecules, we measured the elasticity of DNA in the presence of ILs ([bmim]Cl and [omim]Cl). As results, the persistence length, stretch modulus, torsional stiffness and twist-stretch coupling exhibited a significant decrease compared to the DNA without ILs binding. Isothermal titration calorimetry analysis indicated that the ILs in the presence of DNA were thermodynamically favored driven by enthalpy and entropy. DNA underwent size transition and conformational change induced by ILs, and the charges of DNA were neutralized by the added ILs. The binding of ILs induced unwinding and softening of DNA. Circular dichroism spectra and MD results indicated that DNA maintained B-conformation after interacting with ILs. Compared to [bmim]+, [omim]+ showed stronger binding affinity to DNA and tended to aggregate on the DNA surface. ILs binding reduced Na+ and water binding on DNA, which likely prevented the hydrolytic reactions that denatured DNA and helped stabilize DNA for the long term. This research provides a critical theoretical foundation for the utilization of ionic liquids in life sciences.

Achieving Enhanced Mobility of Ions in Ionic Liquid-Based Gel Polymer Electrolytes By Incorporating Inorganic Nanofibers for Li-Ion Battery

Polymer electrolytes have received much attention in Li-ion battery research because of their unique properties, such as, high ionic conductivity, high mechanical strength including good electrode-electrolyte contact. A major research has been focused on improving the conductivity while retaining the mechanical stability of polymer electrolytes. In this context, ionic liquid-based gel polymer electrolytes are an excellent candidate. A detailed NMR investigation of PMMA-ILs gels electrolytes probing the structure and dynamics of ions was recently reported.[1] The presence of ILs in polymer matrix not only improves the conductivity but also enhances the self-healing capability. In another study, self-healing capability that reduces the dendrite formation at the interface has been discovered, for example, in PVDF-HFP-ILs electrolyte.[2] In this regard, this work reports the possible ways to enhance the ionic conductivity of such polymer electrolyte further by adding Al2O3 nanofibers. A series of PVDF-HFP-ILs with 1M LiTFSI in EMIMTFSI at different ratios of Al2O3nanofibers were prepared through solution cast technique. The dynamics of ions confined within polymer-Al2O3 matrix was explored through Impedence and PFG NMR spectroscopy. The amorphocity and the distribution of Al2O3 nanofibers are studied through XRD and SEM-EDX analyses. Lastly, the local structure of ions and their interaction with polymer and Al2O3 nanofibers were established through a detailed solid-state NMR analyses detecting 1H, 27Al, 13C, 19F, 7Li nuclei including 2D 13C{1H} HETCOR experiments. A reasonable enhancement in terms of ionic conductivity was observed with the addition of Al2O3 nanofibers, which improves the conducting pathways within the polymer network.[1] M. N. Garaga, N. Jayakody, C. C. Fraenza, B. Itin, and S. Greenbaum, Journal of Molecular Liquids 329, 115454 (2021).[2] T. Chen, W. Kong, Z. Zhang, L. Wang, Y. Hu, G. Zhu, R. Chen, L. Ma, W. Yan, Y. Wang, J. Liu, and Z. Jin, Nano Energy 54, 17 (2018).

Screening of lactic acid bacteria stable in ionic liquids and lignocellulosic by-products for bio-based lactic acid production

Lignocellulosic biomass are promising renewable resources for production of biofuels and platform chemicals. The present study encompasses the screening and isolation of lactic acid bacteria (LAB), stable in the presence of ionic liquids ([EMIM][OAc], [BMIM][MeSO4], and [BMIM][Cl]) and lignocellulosic inhibitors (HMF and furfural), and explores them for effective bio-based lactic acid production. Nineteen LAB producing isolates were identified based on their morphological, biochemical and 16S rRNA sequence analysis. Among these five LAB strains namely P. pentosaceus SKL-7, L. fallax SKL-15, L. plantarum SKL-19, L. paracasei SKL-21, and L. plantarum SKL-22 grew well in presence of ILs [EMIM][OAc], [BMIM][MeSO4], and [BMIM][Cl]. The L. plantarum SKL-22 exhibited relatively high tolerance with highest specific growth rates in presence of 0.5% and 1% [BMIM][MeSO4] and [BMIM][Cl]. Overall, L. plantarum SKL-22 produced reasonable good amount of lactic acid 34.26 g/l. It appears a promising strain for one-pot production of lactic acid from lignocellulosic biomass.

Microwave-assisted lipid extraction from Chlorella vulgaris in water with 0.5%–2.5% of imidazolium based ionic liquid as additive

Microwave is a good candidate towards lipid extraction from microalgae in a bid to reduce the overall energetic consumption and extraction time. 1-octyl-3-methylimidazolium-based ILs belonging to 1st generation and 2nd generations, have been used. At 2.5% of [Omim][OAc] in the medium, 19.2% of lipid were obtained, while the conventional IL-less system only yielded 10.9%. More interestingly, the extraction efficiency increases with increasing amount of IL. A broader range of fatty acid profiles was also found to be extracted in the presence of ILs. The lipid extraction ability of the ILs was further confirmed and even dramatically enhanced under high pressure microwave irradiation. At 1.5% IL, the lipid yield reached 37% with FAME profile mirroring the results obtained by hydrophobic IL based extraction. The energy balance calculation have shown a reduction in the energy loss with the different type of IL used resulting in a 12% net energy gain with the [Omim][NTf2] IL based extraction. A key finding in this study suggests that both the polarity of the ILs and the electronegativity of the anions play an important role in the type of lipids extracted.

Electrostatic Stabilization of Single-Atom Catalysts by Ionic Liquids

Summary In single-atom catalysts (SACs), the isolated metal atoms on solid support are often charged. Taking advantage of this common feature, we establish ionic liquid-stabilized single-atom catalysts (ILSSACs) employing electrostatic interaction as a general stabilization strategy. While Pt nanoparticles were formed on hydroxyapatite after reaction when unprotected, Pt remained atomically dispersed on ionic liquid-stabilized samples. Density functional theory calculations reveal that the activation energy for the transformation of two isolated Pt atoms to a Pt dimer increases remarkably from 0.11 to 0.72 eV with the protection of [Bmim][BF4]. The presence of ILs also tunes the electronic state of Pt1, inducing an order-of-magnitude hydrogenation activity increase. The simple stabilization strategy is easily extended to SACs comprising various metal atom-support combinations. For instance, ILs significantly improved the stability and selectivity of a Pd1 catalyst for the hydrogenation of acetylene, thus outperforming unprotected SACs.

Insights into the effect of imidazolium-based ionic liquids on chemical structure and hydrolytic activity of microbial lipase.

This work studied the effect of the cation alkyl chain length of 1-alkyl-n-methylimidazolium chloride ([Cnmim]Cl)-based ILs on the activity of Aspergillus niger lipase. First, the lipase activity in the presence of different ILs concentration over time was determined. ILs with shorter cation alkyl side chain length, namely [C4mim]Cl and [C6mim]Cl, promoted an increase of lipase activity; while, [C8mim]Cl, depending on its concentration, maintained or decreased the enzyme activity. In the presence of ILs with longer cation alkyl chain length, i.e., [C10mim]Cl and [C12mim]Cl, the lipase relative activity was reduced with 0.1 (%v/v) and until suppressed ([C12mim]Cl at 0.3 (%v/v)) as a result of irreversible changes in its secondary structure. Fluorescence and circular dichroism spectroscopy analysis confirmed the results achieved. These findings show that [Cnmim]Cl-based ILs can exert different behavior on the lipase' activity (enhance, maintain or even inhibit) and structural conformation, depending on the cation alkyl chain length and their relative concentration.

Application of Electrolyte Based Model on Ionic Liquids-Methane Hydrates Phase Boundary

In the current study, the phase behaviour of selected methane (CH4) hydrate-Ionic Liquids (ILs) systems were predicted via Dickens and Quinby-Hunt model. The model chosen is an electrolyte-based model; therefore easily accommodate ILs that are molten salts. The experimental hydrate vapour liquid Equilibrium (HLwVE) data of ILs was extracted from various literature sources for validation of the applied model. The overall predicted results suggested that the studied predictive model found in line with the experimental literature data for almost all the studied systems. The maximum deviation observed from the pyrrolidinium family of IL which also found to less than 0.67 K. Apparently it can be concluded that the selective model could applicable for accurate prediction of thermodynamic hydrate phase boundaries of methane hydrates in the presence of ILs. Since hydrate experimentations are very time-consuming, accurate thermodynamic predictions of hydrate phase are very crucial for exploring various hydrate-based technologies like flow assurance, natural gas recovery and gas storage and transportations.

Dehydrated DNA in B-form: ionic liquids in rescue.

The functional B-conformation of DNA succumbs to the A-form at low water activity. Methods for room temperature DNA storage that rely upon ‘anhydrobiosis’, thus, often encounter the loss of DNA activity due to the B→A-DNA transition. Here, we show that ionic liquids, an emerging class of green solvents, can induce conformational transitions in DNA and even rescue the dehydrated DNA in the functional B-form. CD spectroscopic analyses not only reveal rapid transition of A-DNA in 78% ethanol medium to B-conformation in presence of ILs, but also the high resistance of IL-bound B-form to transit to A-DNA under dehydration. Molecular dynamics simulations show the unique ability of ILs to disrupt Na+ ion condensation and form ‘IL spine’ in DNA minor groove to drive the A→B transition. Implications of these findings range from the plausible use of ILs as novel anhydrobiotic DNA storage medium to a switch for modulating DNA conformational transitions.

Detecting hybridization by likelihood calculation of gene tree extra lineages given explicit models

Abstract Explanations for gene tree discordance with respect to a species tree are commonly attributed to deep coalescence (also known as incomplete lineage sorting [ILS]), as well as different evolutionary processes such as hybridization, horizontal gene transfer and gene duplication. Among these, deep coalescence is usually quantified as the number of extra linages and has been studied as the principal source of discordance among gene trees, while the other processes that could contribute to gene tree discordance have not been fully explored. This is an important issue for hybridization because interspecific gene flow is well documented and widespread across many plant and animal groups. Here, we propose a new way to detect gene flow when ILS is present that evaluates the likelihood of different models with various levels of gene flow, by comparing the expected gene tree discordance, using the number of extra lineages. This approach consists of proposing a model, simulating a set of gene trees to infer a distribution of expected extra lineages given the model, and calculating a likelihood function by comparing the fit of the real gene trees to the simulated distribution. To count extra lineages, the gene tree is first reconciled within the species tree, and for a given species tree branch the number of gene lineages minus one is counted. We develop a set of r functions to parallelize software to allow simulations, and to compare hypotheses via a likelihood ratio test to evaluate the presence of gene flow when ILS is present, in a fast and simple way. Our results show high accuracy under very challenging scenarios of high impact of ILS and low gene flow levels, even using a modest dataset of 5–10 loci and 5–10 individuals per species. We present a powerful and fast method to detect hybridization in the presence of ILS. We discuss its advantage with large dataset (such as genomic scale), and also identifies possible issues that should be explored with more complex models in future studies.

Assessment of ionic liquids' toxicity through the inhibition of acylase I activity on a microflow system

Acylase I (ACY I) plays a role in the detoxication and bioactivation of xenobiotics as well in other physiological functions. In this context, an automated ACY I assay for the evaluation of ionic liquids' (ILs) toxicity was developed. The assay was implemented in a sequential injection analysis (SIA) system and was applied to eight commercially available ILs. The SIA methodology was based on the deacetylation of N-acetyl-l-methionine with production of l-methionine, which was determined using fluorescamine. ACY I inhibition in the presence of ILs was monitored by the decrease of fluorescence intensity. The obtained results confirmed the influence of ILs' structural elements on its toxicity and revealed that pyridinium and phosphonium cations, longer alkyl side chains and tetrafluoroborate anion displayed higher toxic effect on enzyme activity.The developed methodology proved to be robust and exhibited good repeatability (RSD < 1.3%, n = 10), leading also to a reduction of reagents consumption and effluents production. Thus, it is expected that the proposed assay can be used as a novel tool for ILs' toxicity screening.

Does 1-Allyl-3-methylimidazolium chloride Act as a Biocompatible Solvent for Stem Bromelain?

The broader scope of ILs in chemical sciences particularly in pharmaceutical, bioanalytical and many more applications is increasing day by day. Hitherto, a very less amount of research is available in the depiction of conformational stability, activity, and thermal stability of enzymes in the presence of ILs. In the present study, the perturbation in the structure, stability, and activity of stem bromelain (BM) has been observed in the presence of 1-allyl-3-methylimidazolium chloride ([Amim][Cl]) using various techniques. This is the first report in which the influence of [Amim][Cl] has been studied on the enzyme BM. Fluorescence spectroscopy has been utilized to map out the changes in the environment around tryptophan (Trp) residues of BM and also to discuss the variations in the thermal stability of BM as an outcome of its interaction with the IL at different concentrations. Further, the work delineates the denaturing effect of high concentration of IL on enzyme structure and activity. It dictates the fact that low concentrations (0.01-0.10 M) of [Amim][Cl] are only changing the structural arrangement of the protein without having harsh consequences on its activity and stability. However, high concentrations of IL proved to be totally devastating for both activity and stability of BM. The observed decrease in the stability of BM at high concentration may be due to the combined effect of cation and anion interactions with the protein residues. The present work is successful in dictating the probable mechanism of interaction between BM and [Amim][Cl]. These results can prove to be fruitful in the studies of enzymes in aqueous IL systems since the used IL is thermally stable and nonvolatile in nature thereby providing a pathway of alteration in the activity of enzymes in potentially green systems.

Influence of microbial adaption and supplementation of nutrients on the biodegradation of ionic liquids in sewage sludge treatment processes

As ionic liquids are winning more attention from industry as a replacement of more hazardous chemicals, some of their structures have the potential to become persistent pollutants due to high stability towards abiotic and biotic degradation processes. Therefore it is important to determine the hazard associated with the presence of ILs in the environment, for example biodegradation under real conditions. Standard biodegradation testing procedures generally permit pre-conditioning of inoculum but do not allow for pre-exposition to the test substance. These are usually conducted in a mineral medium which does not provide additional organic nutrients. Though very valuable, as a point of reference, these tests do not fully represent real conditions. In in situ conditions, for example in wastewater treatment plants or natural soils and water bodies, the presence of readily available sources of energy and nutrients as well as the process of adaptation may often alter the fate and metabolic pathways of xenobiotics. Our results have shown that these are the opposing processes influencing the biodegradation rate of ILs in sewage sludge. The results have significant practical implications with respect to the assessment of biodegradability and environmental fate of ILs and other xenobiotics in environmental conditions and their potential remediation options.

Investigation of the Role of Ionic Liquids in Tuning the pK a Values of Some Anionic Indicators

The effect of imidazolium-based ionic liquids, ([C12mim][Cl] and [C8mim][Cl]), on the acid-base equilibria of two sulfonated indicators has been studied. The presence of ILs leads to decreased pKa values because of the stronger electrostatic interaction of cationic ILs with the basic forms of the indicators with more negative charge. The longer alkyl side chain of [C12mim][Cl] compared to [C8mim][Cl] results in stronger hydrophobic interaction of this IL with the basic forms of the dyes leading to a more effective decrease in the pKa values. Also, the transition points and transition intervals of the acid-base titration curves of the indicators were affected by the presence of ILs. It was found that the IL interaction with acid-base indicators also results in sharpening the acid-base titration curves of the indicators. From these observations, it is concluded that the presence of ILs can tune the pKa values of indicators. All the experiments were performed spectrophotometrically and the results were obtained using curve fitting methods.

Histone deacetylase inhibition improves differentiation of dendritic cells from leukemic blasts of patients with TEL/AML1-positive acute lymphoblastic leukemia

Histone deacetylase inhibitors (HdI) could potentially improve the differentiation of leukemic dendritic cells (DC). Therefore, bone marrow samples from 100 children with acute lymphoblastic leukemia (ALL) were cultured in the cytokines TNF-alpha, GM-CSF, c-kit ligand, and fetal liver tyrosine kinase 3 ligand, with or without IL-3 and -4 and after administration of HdI valproic acid (VAL), suberoylanilide hydroxamic acid (SAHA), isobutyramid, or trichostatin A. Among the tested samples, 25 were positive for the chromosomal translocation t(12;21), encoding the fusion gene translocation ETS-like leukemia/acute myeloid leukemia 1 (TEL/AML1). SAHA increased CD83 expression of TEL/AML1-positive blasts in conditions without ILs, and SAHA and VAL increased the number of CD86(+)80(-) cells in the presence of ILs. VAL and isobutyramid supported the allostimulatory capacities of TEL/AML1-positive, leukemic DC; VAL and SAHA reduced those of TEL/AML1-negative DC. Cytotoxic T cells sensitized with leukemic DC produced more IFN-gamma and TNF-alpha upon presentation of the TEL/AML1 peptide. They also induced the cytotoxic lysis of nondifferentiated blasts, which was enhanced when TEL/AML1-positive DC had developed after addition of VAL or SAHA. Therefore, the use of HdI in the differentiation of leukemic DC from patients with TEL/AML1-positive ALL is recommended.

Ionic liquids as electrolytes for nonaqueous capillary electrophoresis.

Acetonitrile is a well-suited medium for nonaqueous capillary electroseparations and enables extending the range of applications of capillary electrophoresis (CE) techniques to more hydrophobic species. In this study, the dialkylimidazolium-based low temperature melting organic salts know as "ionic liquids" (ILs) are used as electrolytes. At room temperature these liquids are miscible with acetonitrile which makes it easy to use them for adjustment of analyte mobility and separation. The anionic part as well as the concentration of an IL influence the general electrophoretic mobility of the buffer system. The separation of different analytes is achieved because they become charged in the presence of ILs in separation media. There is also a possibility for a complex formation between the solute and the electrolyte which alters the mobility of the solute. A selected application of separations of phenols and aromatic acids will be discussed.