Deep eutectic solvents functionalized polymers for easily and efficiently promoting biocatalysis

Ionic liquids and deep eutectic solvents for the stabilization of biopharmaceuticals: A review

Biopharmaceuticals have allowed the control of previously untreatable diseases. However, their low solubility and stability still hinder their application, transport, and storage. Hence, researchers have applied different compounds to preserve and enhance the delivery of biopharmaceuticals, such as ionic liquids (ILs) and deep eutectic solvents (DESs). Although the biopharmaceutical industry can employ various substances for enhancing formulations, their effect will change depending on the properties of the target biomolecule and environmental conditions. Hence, this review organized the current state-of-the-art on the application of ILs and DESs to stabilize biopharmaceuticals, considering the properties of the biomolecules, ILs, and DESs classes, concentration range, types of stability, and effect. We also provided a critical discussion regarding the potential utilization of ILs and DESs in pharmaceutical formulations, considering the restrictions in this field, as well as the advantages and drawbacks of these substances for medical applications. Overall, the most applied IL and DES classes for stabilizing biopharmaceuticals were cholinium-, imidazolium-, and ammonium-based, with cholinium ILs also employed to improve their delivery. Interestingly, dilute and concentrated ILs and DESs solutions presented similar results regarding the stabilization of biopharmaceuticals. With additional investigation, ILs and DESs have the potential to overcome current challenges in biopharmaceutical formulation.

Highly efficient determination of metal ion in cosmetic samples by reversed-phase liquid-liquid microextraction based on green hydrophobic deep eutectic solvent

In this paper, a green hydrophobic deep eutectic solvent (HDES) composed of menthol and hexanoic acid was employed to dissolve cosmetics containing Cd2+ and Cd2+ was extracted using an EDTA-2Na saturated solution, analyzed by FAAS. The study found that HDES-1 can be recycled and reused well; the stability constants of Cd2+ EDTA chelates play an important role in the extracting process; the optimum conditions were: the solubility of HDES-1 was 20 mL/g for cosmetic sample at an indoor temperature of around 10 °C; the dissolver-extractant ratio was 2:1; the LOD was 0.037 mg/kg; the RSD was 3.5%; and the recovery was 85.5-118.3%. The developed method was successfully applied to actual cosmetic samples with satisfactory results, and it was also applied for the determination of Mg2+, Mn2+, and Cu2+ in cosmetic samples.

A green QuEChERS syringe filter based micro-solid phase extraction using hydrophobic natural deep eutectic solvent as immobilized sorbent for simultaneous analysis of five anti-diabetic drugs by HPLC-UV

BACKGROUND

Here, it has been discussed about creating a specific and sustainable analytical technique for monitoring anti-diabetic drugs in order to accurately determine the dosage in patients and reduce side effects, remove them from wastewater (as emerging contaminants), and ultimately abate pharmaceutical pollutants in the environment.

RESULTS

In this research, a green and reproducible Quick Easy Cheap Effective Rugged Safe (QuEChERS) method based on syringe filter based micro-solid phase extraction (SF-μSPE) coupled with HPLC-UV using a green sorbent was developed and optimized for the extraction of five anti-diabetic drugs from wastewater, serum, and plasma real samples. A novel green sorbent composed of a liquid mixture of thymol: menthol ([Thy]:[Men], 1:1) hydrophobic natural deep eutectic solvent (HNADES) and curcumin (Cur) immobilized into the non-toxic and biodegradable polyvinyl alcohol (PVA) electrospun nanofibers' mat was synthesized simply via cheap equipment. Cur was added to enhance the hydrophobicity and functionality of the sorbent. The immobilization process was performed by soaking the mat in the liquid mixture for a specific duration. The correct synthesis and experimental molar ratio of the HNADES components were confirmed by ATR-FTIR and NMR (1H and 13C) spectroscopy. The prepared green sorbent (Cur-HNADES/PVA) was characterized using ATR-FTIR, FE-SEM, EDX/EDX mapping analysis, and water contact angle (WCA) measurement, and it exhibited satisfactory adsorption capacity for the target analytes.

SIGNIFICANCE

Under optimal conditions (pH = 6.0, adsorption cycle = 3, sample volume = 5.0 mL, desorption cycle = 1, type and volume of elution = 80:20 %v/v MeOH/ACN and 500.0 μL), the method was validated in terms of specificity, linear dynamic ranges (LDRs = 0.1-2000.0 μg L-1 and 0.1-1800.0 μg L-1), limits of detection (LODs = 0.03-0.09 μg L-1), and precision (within-day RSDs% = 0.32-1.45% and between-day RSDs% = 0.59-2.03%). Evaluation of the greenness aspects of the proposed method was accomplished using the Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE) approaches. It is noteworthy that the conducted research represents the first report of the synthesis and application of this novel and green sorbent for the determination of anti-diabetic drugs in the mentioned real samples.

Synthesis of new hybrid pyridines catalyzed by Fe3O4@SiO2@urea-riched ligand/Ch-Cl

Herein, a new heterogeneous catalytic system through modification of urea functionalized magnetic nanoparticles with choline chloride [Fe₃O₄@SiO₂@urea-riched ligand/Ch-Cl] was designed and synthesized. Then, the synthesized Fe₃O₄@SiO₂@urea-riched ligand/Ch-Cl was characterized by using FT-IR spectroscopy, FESEM, TEM, EDS-Mapping, TGA/DTG and VSM techniques. After that, the catalytic usage of Fe₃O₄@SiO₂@urea-riched ligand/Ch-Cl was investigated for the synthesis of hybrid pyridines with sulfonate and/or indole moieties. Delightfully, the outcome was satisfactory and the applied strategy represents several advantages such as short reaction times, convenience of operation and relatively good yields of obtained products. Moreover, the catalytic behavior of several formal homogeneous DESs was investigated for the synthesis of target product. In addition, a cooperative vinylogous anomeric-based oxidation pathway was suggested as rational mechanism for the synthesis of new hybrid pyridines.

Design Strategy and Application of Deep Eutectic Solvents for Green Synthesis of Nanomaterials

The first report of deep eutectic solvents (DESs) was released in 2003 and was identified as a new member of ionic liquid (IL), involving innovative chemical and physical characteristics. Using green solvent technology concerning economical, practical, and environmental aspects, DESs open the window for sustainable development of nanomaterial fabrication. The DESs assist in different fabrication processes and design nanostructures with specific morphology and properties by tunable reaction conditions. Using DESs in synthesis reactions can reduce the required high temperature and pressure conditions for decreasing energy consumption and the risk of environmental contamination. This review paper provides the recent applications and advances in the design strategy of DESs for the green synthesis of nanomaterials. The strategy and application of DESs in wet-chemical processes, nanosize reticular material fabrication, electrodeposition/electrochemical synthesis of nanostructures, electroless deposition, DESs based nano-catalytic and nanofluidic systems are discussed and highlighted in this review.

The Separation of Chlorobenzene Compounds from Environmental Water Using a Magnetic Molecularly Imprinted Chitosan Membrane

In this work, a magnetic molecularly imprinted chitosan membrane (MMICM) was synthesized for the extraction of chlorobenzene compounds in environmental water using the membrane separation method. The optimal extraction amount for chlorobenzene (9.64 mg·L⁻¹) was found to be a 1:2 solid to liquid ratio, with a 20 min extraction time and 35 °C extraction temperature. This method proved to be successfully applied for the separation and trace quantification of chlorobenzene compounds in environmental water, with the limit of detection (LOD) (0.0016–0.057 ng·L⁻¹), limit of quantification (LOQ) (0.0026–0.098 ng·L⁻¹), and the recoveries ranging (89.02–106.97%).

Removal of trace DNA toxic compounds using a Poly(deep eutectic solvent)@Biomass based on multi-physical interactions

DNA toxic compounds (DNA-T-Cs), even in trace amounts, seriously threaten human health and must be completely eliminated. However, the currently used separation media face great challenges in removing trace DNA-T-Cs. Based on the functional advantages of deep eutectic solvents (DESs) and the natural features of biomass (BioM), a series of Poly(DES)@BioMs functioning as adsorbents were prepared for the removal of aromatic/hetero-atomic DNA-T-Cs at the ppm level. After optimisation of experimental conditions, the removal efficiency for DNA-T-Cs ranged from 92.4% to 96.0% with an initial concentration of 20.0 ppm, a temperature of 30 °C, duration of 30 min, and pH of 7.0. The removal processes between the DNA-T-Cs and Poly(DES)@BioMs are well described in the Temkin equilibrium and second-order kinetic adsorption models, and the desorption processes are well shown in the Korsmeryer-Peppas equilibrium and zero-order kinetic models. Molecular simulations revealed that the removal interactions include hydrogen bonding, π-π stacking, and hydrophobic/hydrophilic effects. The removal efficiency for the DNA-T-Cs at 8.0 ppm in industrial sewage ranged from 69.7% to 102%, while the removal efficiency for the DNA-T-Cs standing alone at 20.0 ppm in a methyl violet drug solution was 95.4%, confirming that the Poly(DES)@BioMs effectively removed trace DNA-T-Cs in field samples.

Photoluminescence with an unusual open-loop and rigid delocalized conjugated structure in quantum dots

It is well known that almost all photoluminescent molecules are aromatic or heterocyclic ring compounds for bioimaging analysis. A question remains as to whether a breakthrough can be achieved regarding a novel photoluminescent molecule without a ring structure, and in a what manner. In this study, we explored the photoelectric conversion and structure of photoluminescent compounds, and constructed an intra-molecular coupling positive-negative-junction (PNJ) with an open-loop and rigid Π₅⁶ delocalized conjugated structure of the coupling p-π conjugate system. This was performed to enable strong absorption of the R/tail-end band for the high probability of an n → π*/n → σ* electron transition for photoluminescence production. Subsequently, the Π₅⁶ structure was formed in a short-chain aliphatic molecule as a hydrolytic product of citric acid and urea, and computational methodology was employed to estimate the feasibility of the molecule photoluminescence. Finally, a quantum dot material was fabricated from the aliphatic molecule, the optical properties of the quantum dots were investigated, and the biocompatibility and bioimaging ability of quantum dots were assessed. This work presents not only a theoretical exploration but also practical application of a new strategy to obtain molecules, compounds, and materials with bioimaging.

A Theoretical Study on Terpene-Based Natural Deep Eutectic Solvent: Relationship between Viscosity and Hydrogen-Bonding Interactions

The aim of this work is to shed light on the origins of unique properties by studying the relationship between viscosity and hydrogen-bonding interactions of terpene-based natural deep eutectic solvents (NADES). Five systems including camphor/formic acid, menthol/acetic acid, menthol/β-citronellol, menthol/lactic acid, and thymol/β-citronellol are prepared (molar ratio 1:1). Their structures and nature of the associated hydrogen bonds are investigated through multiple methods and theories. The viscosity of NADES is consistent with the product of hydrogen-bond number and lifetime. Through visualization of non-covalent interactions, terpene-acid-based NADES with single sites show the lowest viscosity among the studied systems because of weak and unstable hydrogen bonding. Inversely, multi-site terpene-acid-based NADES possess relatively high viscosity. Owing to the stability of hydrogen bonds in the network, the terpene-terpene-based system is in the middle level of viscosity. In-depth analysis of these hydrogen bonds shows that they can be classified as "weak to medium" and are mainly derived from electrostatic interactions. Moreover, there is an obvious connection between viscosity and hydrogen-bonding strength (integrated core-valence bifurcation index) in the networks. The discovery of intrinsic rules between viscosity and hydrogen-bonding interactions is beneficial for the design of novel low-viscosity NADES in the future.

New deep eutectic solvent based superparamagnetic nanofluid for determination of perfluoroalkyl substances in edible oils

Perfluoroalkyl substances (PFASs) have been identified as global pollutants and raise considerable food safety concerns. However, the development of an analytical method with satisfied pretreatment performance for PFASs with varying alkyl chain length in the fatty samples remains a challenge. We describe herein the preparation of superparamagnetic nanofluid, based on a new choline chloride/1-(o-tolyl)biguanide deep eutectic solvent (DES) system, for direct extraction of perfluoroalkyl carboxylic acids from edible oils. Target PFASs, especially the short-chain one, all possessed high recoveries (90-109% with intra-day and inter-day precision below 10%). This was achieved by adjusting the constituent ratio of DES for balancing the anion-exchange (electrostatic) interactions and hydrogen-bond interactions. Employing the prepared nanofluid in magnetic microextraction, followed by high-resolution mass spectrum analysis, resulted in a rapid (15 min for pretreatment), simple, sensitive (detection limit: 0.3-1.6 pg g^-1), and efficient method for the enrichment and determination of trace PFASs. Furthermore, the introducing of N-H⋯F weak force increased the pretreatment selectivity to effectively reduce the matrix effect. At the end of the study, the proposed methodology was successfully applied to the analysis of target analytes in real samples.

Greener, Faster, Stronger: The Benefits of Deep Eutectic Solvents in Polymer and Materials Science

Deep eutectic solvents (DESs) represent an emergent class of green designer solvents that find numerous applications in different aspects of chemical synthesis. A particularly appealing aspect of DES systems is their simplicity of preparation, combined with inexpensive, readily available starting materials to yield solvents with appealing properties (negligible volatility, non-flammability and high solvation capacity). In the context of polymer science, DES systems not only offer an appealing route towards replacing hazardous volatile organic solvents (VOCs), but can serve multiple roles including those of solvent, monomer and templating agent-so called "polymerizable eutectics." In this review, we look at DES systems and polymerizable eutectics and their application in polymer materials synthesis, including various mechanisms of polymer formation, hydrogel design, porous monoliths, and molecularly imprinted polymers. We provide a comparative study of these systems alongside traditional synthetic approaches, highlighting not only the benefit of replacing VOCs from the perspective of environmental sustainability, but also the materials advantage with respect to mechanical and thermal properties of the polymers formed.

Solid-Phase Extraction of Catechins from Green Tea with Deep Eutectic Solvent Immobilized Magnetic Molybdenum Disulfide Molecularly Imprinted Polymer

A type of molecular-imprinted polymer with magnetic molybdenum disulfide as a base and deep eutectic solvent as a functional monomer (Fe₃O₄@MoS₂@DES-MIP) was prepared with surface molecular imprinting method. It was applied as the adsorbent for the selective recognition and separation of (+)-catechin, (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, and (-)-epigallocatechin gallate in green tea in the process of magnetic solid-phase extraction (MSPE) combined with high-performance liquid chromatography (HPLC). The structure of Fe₃O₄@MoS₂@DES-MIP was characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The adsorption properties and selective recognition ability on (-)-epigallocatechin gallate and the other four structural analogues were examined and compared. The results show that the polymer has excellent selective recognition ability for (-)-epigallocatechin gallate, and its adsorption capacity was much higher than that of structural analogues. The Fe₃O₄@MoS₂@DES-MIP not only has the special recognition ability to template a molecule, but also can be separated by magnets with high separation efficiency and can be used in MSPE.

Evaluation of CO2-induced azole-based switchable ionic liquid with hydrophobic/hydrophilic reversible transition as single solvent system for coupling lipid extraction and separation from wet microalgae

The utilization of microalgae as bioenergy source was limited by the excessive cost and energy consumption during the process of lipid extraction and separation. CO₂-induced switchable ionic liquids (S-ILs) with reversible hydrophobic-hydrophilic conversion were synthesized and applied for lipid extraction and separation. The reversible transition mechanism of switchable IL is due to the formation of carbamate. The novel approach based on S-ILs was developed for lipid extraction from wet microalgae, which coupled microalgae cell disruption, lipid extraction, separation, and solvent recovery process without additional solvents. The highest lipid extraction efficiencies from wet microalgae were obtained by C₆DIPA-Im, and the lipids were recovered from the extraction phase by simply bubbling CO₂. Furthermore, C₆DIPA-Im maintained more than 83.6 ± 3.6% of its initial lipid extraction efficiency after recycling five times. The S-IL based extraction and separation method provides a new strategy for sustainable bioenergy production.