Mechanisms of Biological Effects of Ionic Liquids: From Single Cells to Multicellular Organisms

The review presents a detailed discussion of the evolving field studying interactions between ionic liquids (ILs) and biological systems. Originating from molten salt electrolytes to present multiapplication substances, ILs have found usage across various fields due to their exceptional physicochemical properties, including excellent tunability. However, their interactions with biological systems and potential influence on living organisms remain largely unexplored. This review examines the cytotoxic effects of ILs on cell cultures, biomolecules, and vertebrate and invertebrate organisms. Our understanding of IL toxicity, while growing in recent years, is yet nascent. The established findings include correlations between harmful effects of ILs and their ability to disturb cellular membranes, their potential to trigger oxidative stress in cells, and their ability to cause cell death via apoptosis. Future research directions proposed in the review include studying the distribution of various ILs within cellular compartments and organelles, investigating metabolic transformations of ILs in cells and organisms, detailed analysis of IL effects on proteins involved in oxidative stress and apoptosis, correlation studies between IL doses, exposure times and resulting adverse effects, and examination of effects of subtoxic concentrations of ILs on various biological objects. This review aims to serve as a critical analysis of the current body of knowledge on IL-related toxicity mechanisms. Furthermore, it can guide researchers toward the design of less toxic ILs and the informed use of ILs in drug development and medicine.

Accelerated lithium-ion diffusion via a ligand 'hopping' mechanism in lithium enriched solvate ionic liquids

Solvate ionic liquids (SILs), equimolar amounts of lithium salts and polyether glymes, are well studied highly customisable "designer solvents". Herein the physical, thermal and ion mobility properties of SILs with increased LiTFSI (LiTFSA) concentration, with ligand 1 : >1 LiTFSI stoichiometric ratios, are presented. It was found that between 60-80 °C, the lithium cation diffuses up to 4 times faster than the corresponding anion or ligand (glyme). These systems varied from viscous liquids to self-supporting gels, though were found to thin exponentially when heated to mild temperatures (50-60 °C). They were also found to be thermally stable, up to 200 °C, well in excess of normal operating temperatures. Ion mobility, assessed under an electric potential via ionic conductivity, showed the benefit of SIL optimisation for attaining greater concentrations of Li+ cations to store charge during supercapacitor charging and discharging. Molecular dynamics simulations interrogate the mechanism of enhanced diffusion at high temperatures, revealing a lithium hopping mechanism that implicates the glyme in bridging two lithiums through changes in the denticity.

Phosphorus-Based α-Amino Acid Mimetic for Enhanced Flame-Retardant Properties in an Epoxy Resin

This work demonstrates the introduction of a phosphonate moiety into a commonly used curing agent, 4,4′-diaminodiphenylmethane (DDM), via an α-aminophosphonate. This compound (DDMP) can be prepared and isolated in analytical purity in under 1h and in good yield (71%). Thermoset polymer (epoxy-derived) samples were prepared using a room-temperature standard cure (SC) and a post-cured (PC) protocol to encourage incorporation of the α-aminophosphonate into the polymer network, with improved flammability properties observed for the latter. Thermogravimetric analysis under a nitrogen atmosphere showed increased char yield at 600°C, and similar observations were made when analysis was conducted in air. Significant reductions in flammability are observed at very low phosphorus content (P%=0.16–0.49%), demonstrated by higher char yields (25.5 from 14.0% in air), decreased burn time from ignition (60 to 24s), and decreased mass loss after ignition (87.6 to 58.5%). Limiting Oxygen Index for the neat polymer (P%=0%, 20.3±0.8%) increased with increasing α-aminophosphonate additive (P%=0.16%, 20.8±0.6%; P%=0.32%, 21.4±0.4%; P%=0.49%, 22.6±0.8%).

Comparison of solvate ionic liquids and DMSO as an in vivo delivery and storage media for small molecular therapeutics

BACKGROUND

Solvate ionic liquids (SILs) are a new class of ionic liquids that are equimolar solutions of lithium bistrifluoromethanesulfonimide in either triglyme or tetraglyme, referred to as G3LiTFSA and G4LiTFSA, respectively. SILs play a role in energy storage lithium batteries, and have been proposed as potential alternatives to traditional organic solvents such as DMSO. G3TFSA and G4TFSA have been shown to exhibit no toxicity in vivo up to 0.5% (v/v), and solubilize small compounds (N,N-diethylaminobenzaldehyde) with full penetrance, similar to DMSO delivered DEAB. Herein, we compare the effects of storage (either at room temperature or - 20 °C) on DEAB solubilized in either DMSO, G3TFSA or G4TFSA to investigate compound degradation and efficacy.

RESULTS

The findings show that DEAB stored at room temperature (RT) for 4 months solubilized in either G3TFSA, G4TFSA or DMSO displayed no loss of penetrance. The same was observed with stock solutions stored at - 20 °C for 4 months; however G4TFSA remained in a liquid state compared to both G3TFSA and DMSO. Moreover, we examined the ability of G3TFSA and G4TFSA to solubilize another small molecular therapeutic, the FGFR antagonist SU5402. G4TFSA, unlike G3TFSA solubilized SU5402 and displayed similar phenotypic characteristics and reduced dlx2a expression as reported and shown with SU5402 in DMSO; albeit more penetrative.

CONCLUSION

This study validates the use of these ionic liquids as a potential replacement for DMSO in vivo as organic solubilizing agents.

Synthesis of α-aminophosphonates using solvate ionic liquids

A range of α-aminophosphonates were accessed in high yields and very rapidly, using solvate ionic liquids as the reaction media.