Therapeutic Role of Deep Eutectic Solvents Based on Menthol and Saturated Fatty Acids on Wound Healing

Drug Delivery Applications of Hydrophobic Deep Eutectic Solvent-in-Water Nanoemulsions: A Comparative Analysis of Ultrasound Emulsification and Membrane-Assisted Nanoemulsification

The emergence of green chemistry and engineering principles to enforce sustainability aspects has ensured the prevalence of green solvents and green processes. Our study addresses this quest by exploring drug delivery applications of hydrophobic deep eutectic solvents (DESs) which are alternative green solvents. Initially, this work showcases the hydrophobic drug solubilization capabilities of a natural hydrophobic DES, menthol, and decanoic acid. To consider biomedical applications wherein polar media are encountered, this work further demonstrates the potential drug delivery application of these systems by encapsulating the anti-inflammatory local anesthetic lidocaine in hydrophobic DES-in-water nanoemulsions. NMR studies confirm the high solubility of the hydrophobic drug in hydrophobic DES comprising menthol and decanoic acid (1:2 molar ratio). Ultrasound emulsification and energy-efficient membrane emulsification techniques were employed to disperse 4% (v/v) DES into a 2% (w/w) Tween 20 surfactant aqueous solution. An isoporous microengineered membrane (nominal pore size ∼ 9 μm) was used to produce lidocaine-loaded DES-based nanoemulsions. Such membrane-assisted nanoemulsification was possible because the hydrophobic DES exhibits relatively low interfacial tension with the continuous phase and acts as a cosurfactant. Moreover, increased concentrations of lidocaine within the DES resulted in a further decrease in the interfacial tension and a lower melting point. Among the kinetic models analyzed to evaluate the release of lidocaine encapsulated in hydrophobic DES-in-water nanoemulsions, the Korsmeyer-Peppas kinetic model provided the best fit. The release constant "n" of <0.5 indicates that the drug release mechanism is predominantly governed by diffusion. Additionally, cytotoxicity against various human cell lines demonstrated the nanoemulsion's potential for anti-inflammatory drug delivery applications. Consequently, the nanoemulsion of DES presents a promising solution for the effective loading and delivery of poorly soluble drugs. This innovative approach enhances drug solubility and bioavailability, providing a versatile platform for controlled drug release. By leveraging the advantages of nanoemulsion technology, our study underscores the potential of DES-based formulations to promote drug delivery systems across a variety of therapeutic applications.

Deep eutectic solvent enhances antibacterial activity of a modular lytic enzyme against Acinetobacter baumannii

In this study, we evaluated the combined effect between MLE-15, a modular lytic enzyme composed of four building blocks, and reline, a natural deep eutectic solvent. The bioinformatic analysis allowed us to determine the spatial architecture of MLE-15, whose components were bactericidal peptide cecropin A connected via a flexible linker to the cell wall binding domain (CBD) of mesophilic 201ϕ2 - 1 endolysin and catalytic domain (EAD) of highly thermostable Ph2119 endolysin. The modular enzyme showed high thermostability with the melting temperature of 93.97 ± 0.38 °C, significantly higher than their natural counterparts derived from mesophilic sources. The minimum inhibitory concentration (MIC) of MLE-15 was 100 µg/mL for a panel of Gram-positive and Gram-negative bacteria, while the MIC of reline ranged from 6.25 to 25% v/v for the same strains. The addition of reline effectively reduced the MIC of MLE-15 from 100 µg/mL to 3.15-50 µg/mL. This combination displayed additive effects for most strains and synergism for extensively antibiotic-resistant Acinetobacter baumannii and Bacillus subtilis. The subsequent evaluation revealed that MLE-15 eliminated planktonic cells of A. baumannii RUH134, but was ineffective against matured biofilms. However, combined with reline, MLE-15 reduced the bacterial load in the matured biofilm by 1.39 log units. Confocal fluorescence microscopy indicated that reline damaged the structure of the biofilm, allowing MLE-15 to penetrate it. Additionally, MLE-15 and its combination with reline eradicated meropenem-persistent cells of A. baumannii RUH134. Effectiveness in lowering the MIC value of MLE-15 as well as protection against antibiotic-tolerant persister cells, indicate that MLE-15 and reline combination is a promising candidate for effective therapies in bacterial infections, which is especially important in the light of the global crisis of antimicrobial resistance.

Structural characterization and physicochemical properties of different hydrophilic natural deep eutectic solvents

To overcome the toxic nature of organic solvents, scientific interest in the use of green solvents, particularly natural deep eutectic solvents (NADES), has increased over the past decade, leading to new applications in the food, nutraceutical, pharmaceutical, and cosmetic industries. Understanding the physicochemical properties and molecular interactions of NADES is essential for uncovering new potential applications in these fields. In this study, several lactic and citric acid-based NADES, as well as chloride choline- and urea-based NADES, were evaluated for their physicochemical properties, including density, pH, viscosity, conductivity, and refractive index. Additionally, nuclear magnetic resonance (NMR), and in particular nuclear Overhauser enhancement spectroscopy (NOESY), was employed to investigate the intermolecular interactions between the NADES components to confirm the formation of the eutectic mixture. The extraction efficiency of the confirmed NADES was tested for extracting polyphenols as a proof of concept to highlight their relationship with the measured properties. Lactic and choline chloride-based NADES provided the highest extraction yields. These results were also compared with the predicted extraction capabilities of each NADES provided by the COSMO-RS software.

Applications of therapeutic deep eutectic solvents (THEDESs) as antimicrobial and anticancer agents

Deep eutectic solvents (DESs) are green alternatives to ionic liquids with wide applications in organic synthesis and catalysis. DESs are characterized by being easily prepared, biodegradable, nontoxic, and noninflammable. When one or more of the DES components is active pharmaceutical ingredient (API), the eutectic mixtures are named as therapeutic deep eutectic solvents (THEDESs). THEDESs are prepared in order to improve the solubility and/or the permeability of the APIs. This review presents a brief summary of the most important THEDESs reported to date having antimicrobial and/or anticancer activities. The challenges and limitations of THEDES preparation were also discussed. The work presented here indicated the importance of THEDES as a promising drug delivery system that can overcome the bioavailability problems while retaining or enhancing the biological activity of its components.

Latest advance anti-inflammatory hydrogel wound dressings and traditional Lignosus rhinoceros used for wound healing agents

Wound healing is a physiological process occurring after the onset of a skin lesion aiming to reconstruct the dermal barrier between the external environment and the body. Depending on the nature and duration of the healing process, wounds are classified as acute (e.g., trauma, surgical wounds) and chronic (e.g., diabetic ulcers) wounds. The latter, often affect millions of people globally, take months to heal or not heal non-healing chronic wounds, are typically susceptible to microbial infection, and are a major cause of morbidity. Wounds can be treated with a variety of non-surgical (topical formulations, wound dressings) and surgical (debridement, skin grafts/flaps) methods. Three-dimensional (3D)-(bio) printing and traditional wound dressings are two examples of modern experimental techniques. This review focuses on several types of anti-inflammatory wound dressings, especially focusing on hydrogels and traditional macro-fungi like L. rhinocerotis as agents that promote wound healing. In this study, we introduced novel anti-inflammatory hydrogel dressings and offered innovative methods for application and preparation to aid in the healing. Additionally, we summarize the key elements required for wound healing and discuss our analysis of potential future issues. These findings suggest that L. rhinocerotis and various anti-inflammatory hydrogels can be considered as conventional and alternative macro-fungi for the treatment of non-communicable diseases. We summarized the development of functional hydrogel dressings and traditional Lignosus rhinoceros used for wound healing agents in recent years, as well as the current situation and future trends, in light of their preparation mechanisms and functional effects.

Natural Deep Eutectic Solvents Combined with Supercritical Carbon Dioxide for the Extraction of Curcuminoids from Turmeric

BACKGROUND

Curcuminoids, the bioactive compounds found in turmeric, exhibit potent antioxidant, anti-inflammatory, and neuroprotective properties. This study aims to enhance the extraction of curcuminoids from turmeric using environmentally friendly solvents supercritical CO2 (scCO2) combined with natural deep eutectic solvents (NADESs) in one process, and to evaluate the resulting biological activity.

METHODS

A Box-Behnken statistical design was applied to optimize scCO2 extraction conditions-pressure, CO2 volume, and temperature-to maximize curcuminoid yield. Next, the menthol and lactic acid NADESs were selected, and these two solvents were combined into a single turmeric extraction process. The biological activity of the resulting extract was evaluated using antioxidant assays (ferric reducing antioxidant power and 2,2-diphenyl-1-picrylhydrazyl) and enzyme inhibition assays (acetylcholinesterase, butyrylcholinesterase, and tyrosinase). Toxicity assessments were conducted on the aquatic invertebrates Daphnia pulex, Artemia sp., and Chironomus aprilinus.

RESULTS

The most effective extraction was achieved using a menthol-lactic acid NADES as a cosolvent, integrated at a 1:20 ratio of plant material to NADESs while in combination with scCO2. The optimized scCO2-NADES extraction resulted in a high curcuminoid yield (33.35 mg/g), outperforming scCO2 extraction (234.3 μg/g), NADESs ultrasound-assisted extraction (30.50 mg/g), and alcohol-based solvents (22.95-26.42 mg/g). In biological assays, the extract demonstrated significant antioxidant activity and effective inhibition of enzymes (acetylcholinesterase, butyrylcholinesterase, and tyrosinase). Toxicity studies showed a concentration-dependent response, with EC50 for Chironomus aprilinus at the level of 0.098 μL/mL and Daphnia pulex exhibiting high sensitivity to the extract.

CONCLUSIONS

This study highlights the potential of combining NADESs and scCO2 extraction in one process, demonstrating the effectiveness of scCO2-NADES extraction in maximizing curcuminoid yield and enhancing bioactivity.

Deep Eutectic Solvents for Essential-Oil Delivery and Bacterial-Infected Wound Healing

Essential oils (EOs) are volatile secondary metabolites of natural plants with multitudinous pharmacological activities. However, limited by their properties, such as low solubility, high volatility, photothermal instability, irritation, release, etc., EOs encounter significant challenges in pharmaceutical applications. Deep eutectic solvents (DESs) have been developed for the transdermal delivery of biomolecules and lipid-soluble drugs. Herein, a series of DES carriers were synthesized to improve the undesirable properties of EOs. We first optimized the DESs according to solubilization and aqueous dispersity using Chimonanthus nitens Oliv. EO (COEO) as a model EO. Then, the EO-DES formulations were diluted to prepare optimal aqueous EO-DES nanoformulations (AqEDs). Mechanically, hydrogen bonding allowed the DES to dissolve the complex components in EOs; meanwhile, the interaction forces, such as π-π stacking and hydrogen bonding, drove the EO-DES to assemble into nanostructures in aqueous conditions, forming AqEDs. Lastly, a case study demonstrated that clove EO-AqEDscould effectively promote methicillin-resistant Staphylococcus aureus-infected wound healing in vivo, along with biocompatibility. This AqED strategy provides a generalized platform for solubilizing EOs and improving their transdermal/topical delivery.

Exploring Deep Eutectic Solvents as Pharmaceutical Excipients: Enhancing the Solubility of Ibuprofen and Mefenamic Acid

Objectives: The study explores the potential of various deep eutectic solvents (DESs) to serve as drug delivery systems and pharmaceutical excipients. The research focuses on two primary objectives: evaluating the ability of the selected DES systems to enhance the solubility of two poorly water-soluble model drugs (IBU and MFA), and evaluating their physicochemical properties, including density, viscosity, flow behavior, surface tension, thermal stability, and water dilution effects, to determine their suitability for pharmaceutical applications. Methods: A range of DES systems containing pharmaceutically acceptable constituents was explored, encompassing organic acid-based, sugar- and sugar alcohol-based, and hydrophobic systems, as well as menthol (MNT)-based DES systems with common pharmaceutical excipients. MNT-based DESs exhibited the most significant solubility enhancements. Results: IBU solubility reached 379.69 mg/g in MNT: PEG 400 (1:1) and 356.3 mg/g in MNT:oleic acid (1:1), while MFA solubility peaked at 17.07 mg/g in MNT:Miglyol 812®N (1:1). In contrast, solubility in hydrophilic DES systems was significantly lower, with choline chloride: glycerol (1:2) and arginine: glycolic acid (1:8) showing the best results. While demonstrating lower solubility compared to the MNT-based systems, sugar-based DESs exhibited increased tunability via water and glycerol addition both in terms of solubility and physicochemical properties, such as viscosity and surface tension. Conclusions: Our study introduces novel DES systems, expanding the repertoire of pharmaceutically acceptable DES formulations and opening new avenues for the rational design of tailored solvent systems to overcome solubility challenges and enhance drug delivery.

Effective recovery of limonene-rich concentrate from lemon residues using terpene-based deep eutectic solvents based on statistical experimental design

INTRODUCTION

Waste by-products of the juice industry appear valuable for the circular economy concept, considering that the peel accounts for almost half of the total fruit weight. Therefore, the recovery of these highly valuable components from relevant biowaste has become a very interesting research topic.

OBJECTIVE

The current study aims to develop an extraction process integrated with hydrophobic deep eutectic solvent (DES) based on statistical experimental design approach.

MATERIAL AND METHODS

Homogenizer-assissted extraction (HAE) was used to recover the citrus extract rich in limonene (the main component of the volatile mixture) from lemon peels. Menthol-based deep eutectic mixtures were accompanied by carboxylic acids (formic, acetic, and propionic acids). Optimization continued on the combination that gave the highest efficiency (in terms of limonene content) among the solvents prepared at different molar ratios (1/1, 1/2, and 2/1). Process parameters were analyzed to optimize the process through central composite design with response surface method (RSM). D-Limonene yield was quantified with gas chromatography-mass spectrometry (GC-MS) with solid-phase microextraction (SPME) technique. The quality of the lemon peel extracts was also evaluated with respect to in vitro bioactivity assays (phenolic content and 2,2-diphenyl-1-picrylhydrazyl [DPPH] free radical scavenging activity).

RESULTS

The maximum yield (3.80 mg-limonene per g fresh sample) was achieved by 2 mg solid/30 mL DES, ~53 sec, and ~8500 rpm. Statistically most effective variable was identified as solid mass, followed by second powers of mixing speed and extraction time at p < 0.0001.

Novel ferrofluid based on hydrophobic deep eutectic solvents for separation and analysis of trace estrogens in environmental water and urine samples

A novel ferrofluid prepared from a hydrophobic deep eutectic solvent (DES) and Fe3O4@graphite composite materials was introduced as a green microextraction medium for the separation and enrichment of trace estrogens in real samples. It was found that the ferrofluid greatly improved the capacity and selectivity of target analytes, benefiting from the enrichment of both DES and Fe3O4@graphite composite materials. Using a combination of high-performance liquid chromatography-fluorescence detection (HPLC-FLD) and vortex-assisted liquid-liquid microextraction (VALLME), a new method was established for simultaneous rapid processing and accurate determination of three estrogens (estradiol [E2], estriol [E3], and ethinyl estradiol [EE2]) in environmental water and urine samples. Key parameters affecting the extraction efficiency were optimized using a single-factor approach and response surface methodology. Under optimal conditions, this method yielded a low limit of detection (1.01 ng L-1, 3.03 ng L-1, and 25.0 ng L-1 for EE2, E2, and E3, respectively), wide linear range (3-200,000 ng L-1), high enrichment factors (9.81-47.2), and satisfactory recovery (73.8-129.0%). Compared with traditional analytical techniques, this method avoids the use of volatile toxic organic extraction solvents and cumbersome phase separation operations.

Innovative Alkanediol-Based Eutectic Solvents for Extracting/Pre-Formulating Dermatologically Valuable Free Fatty Acids from Spirulina and Porphyridium Cakes

The growing demand for phycobiliproteins from microalgae generates a significant volume of by-products, such as extraction cakes. These cakes are enriched with products of interest for the cosmetics market, namely free fatty acids, particularly polyunsaturated (PUFA). In this work, two cakes, one of spirulina and one of Porphyridium cruentum, were valorized using innovative natural hydrophobic deep eutectic solvents (NaDES) based on alkanediols. The most promising NaDES, as determined by physicochemical properties and screening, are mixtures of alkanediols and fatty acids. These include the mixtures of 1,3-propanediol and octanoic acid (1:5, mol/mol) and 1,3-propanediol and octanoic and decanoic acid (1:3:1, mol/mol). Two extractive processes were implemented: ultrasound-assisted extraction and an innovative mechanical process involving dual asymmetric centrifugation. The second process resulted in the production of extracts significantly enriched in PUFA, ranging from 65 to 220 mg/g dry matter with the two cakes. The extracts and NaDES demonstrated good safety with respect to epidermal keratinocyte viability (>80% at 200 µg/mL). The study of their impact on commensal and pathogenic cutaneous bacteria demonstrated significant effects on the viability of Staphylococcus aureus and Staphylococcus epidermidis (>50% decrease at 200 µg/mL) while preserving Corynebacterium xerosis and Cutibacterium acnes. These results highlight the potential of valorizing these co-products using alkanediol-based NaDES, in a strategy combining an active vector (NaDES) and a growth regulator extract, for the management of cutaneous dysbiosis involving staphylococci.

Comparison of the Antibacterial Activity of Selected Deep Eutectic Solvents (DESs) and Deep Eutectic Solvents Comprising Organic Acids (OA-DESs) Toward Gram-Positive and Gram-Negative Species

Deep eutectic solvents (DESs) have been intensively investigated in recent years for their antibacterial properties, with DESs that comprise organic acids (OA-DESs) showing promising antibacterial action. However a majority of the reports focused only on a limited number strains and techniques, which is not enough to determine the antibacterial potential of a substance. To bridge this gap, the antibacterial activity of classical DESs and OA-DESs is assessed on twelve Gram-negative and Gram-positive bacteria strains, with some of them exhibiting specific resistance toward antibiotics. The investigated formulations of OA-DESs comprise glycolic, malic, malonic, and oxalic acids as representatives of this group. Using a range of microbiological assays as well as physicochemical characterization methods, a major difference of the effectiveness between the two groups is demonstrated, with OA-DESs exhibiting, as expected, greater antibacterial effectiveness than classical DESs. Most interestingly, slight differences in the minimum inhibitory and bactericidal concentration values as well as time-kill kinetics profiles are observed between Gram-positive and Gram-negative strains. Transmission electron microscopy analysis reveals the effect of the treatment of the bacteria with the representatives of both groups of DESs, which allows us to better understand the possible mechanism-of-action of these novel materials.

Deep eutectic solvent self-assembled reverse nanomicelles for transdermal delivery of sparingly soluble drugs

BACKGROUND

Transdermal delivery of sparingly soluble drugs is challenging due to their low solubility and poor permeability. Deep eutectic solvent (DES)/or ionic liquid (IL)-mediated nanocarriers are attracting increasing attention. However, most of them require the addition of auxiliary materials (such as surfactants or organic solvents) to maintain the stability of formulations, which may cause skin irritation and potential toxicity.

RESULTS

We fabricated an amphiphilic DES using natural oxymatrine and lauric acid and constructed a novel self-assembled reverse nanomicelle system (DES-RM) based on the features of this DES. Synthesized DESs showed the broad liquid window and significantly solubilized a series of sparingly soluble drugs, and quantitative structure-activity relationship (QSAR) models with good prediction ability were further built. The experimental and molecular dynamics simulation elucidated that the self-assembly of DES-RM was adjusted by noncovalent intermolecular forces. Choosing triamcinolone acetonide (TA) as a model drug, the skin penetration studies revealed that DES-RM significantly enhanced TA penetration and retention in comparison with their corresponding DES and oil. Furthermore, in vivo animal experiments demonstrated that TA@DES-RM exhibited good anti-psoriasis therapeutic efficacy as well as biocompatibility.

CONCLUSIONS

The present study offers innovative insights into the optimal design of micellar nanodelivery system based on DES combining experiments and computational simulations and provides a promising strategy for developing efficient transdermal delivery systems for sparingly soluble drugs.

Pharmaceutical applications of therapeutic deep eutectic systems (THEDES) in maximising drug delivery

The issue of poor solubility of active pharmaceutical ingredients (APIs) has been a salient area of investigation and novel drug delivery systems are being developed to improve the solubility of drugs, enhance their permeability and thereby their efficacy. Several techniques for solubilization enhancement of poorly soluble drugs are often employed at various stages of pharmaceutical drug product development. One such delivery system is the therapeutic deep eutectic system (THEDES), which showed great potential in the enhancement of solubility and permeability of drugs and ultimately augmenting their bioavailability. THEDES are made by mixing drugs with deep eutectic solvents (DESs) in a definite molar ratio by the hit and trial method. The DESs are a new class of green solvents which are non-toxic, cheap, easy to prepare, biodegradable and have multiple applications in the pharmaceutical industry. The terminologies such as ionic liquids (ILs), DES, THEDES, and therapeutic liquid eutectic systems (THELES) have been very much in use recently, and it is important to highlight the pharmaceutical applications of these unexplored reservoirs in drug solubilization enhancement, drug delivery routes, and in the management of various diseases. This review is aimed at discussing the components, formulation strategies, and routes of administration of THEDES that are used in developing the formulation. Also, the major pharmaceutical applications of THEDES in the treatment of various metabolic and non-metabolic diseases are reviewed.

Structural insights into novel therapeutic deep eutectic systems with capric acid using 1D, 2D NMR and DSC techniques with superior gut permeability

Therapeutic deep eutectic solvents (THEDSs) are the best exemplification of green alternative formulations of active pharmaceutical ingredients (APIs) that offer superlative properties of APIs. Previously, THEDESs of risperidone, fentanyl and levofloxacin with capric acid (CA) were developed by our group. These APIs share cyclic tertiary amine nuclei. Herein, DESs of two drugs bearing cyclic tertiary amine nucleus, namely, droperidol and aripiprazole, in the presence of CA, were investigated as model drugs. Comprehensive analyses were conducted using liquid-state 1D and 2D NMR and differential scanning calorimetry (DSC) to elucidate the regiochemistry and thermodynamic mechanisms bringing about those THEDESs. Everted gut sac technique was used to study the flux of the developed THEDESs. 1D and 2D NMR techniques analyses revealed the importance of cyclic tertiary amine nuclei in forming interactions with CA. This was confirmed by the downfield shift of the protons proximal to the tertiary amine groups compared to the individual drugs. Diffusion NMR analysis (DOSY) showed a significant reduction in the diffusion coefficient of CA in the mixed system compared with CA in isolation. Thermal analysis of the two drugs revealed that the drugs have a low tendency to recrystallise upon melting but rather vitrify from a melt to form an amorphous solid. Interestingly, the superior absorption and flux of the THEDES formulation of droperidol was demonstrated using the ERIS. Collectively, this work provides a green method to attain liquid formulations of APIs with enhanced pharmacokinetic features.

Eutectic solutions for healing: a comprehensive review on therapeutic deep eutectic solvents (TheDES)

OBJECTIVE

TheDES are formed by mixing a Hydrogen Bond Donor (HBD) and a Hydrogen Bond Acceptor (HBA) in appropriate molar ratios. These solvents have been shown to enhance drug solubility, permeability, and delivery. The main objective of the present article is to review these advantages of TheDES.

SIGNIFICANCE

TheDES show unique properties, such as low toxicity, biodegradability, improved bioavailability and enhanced drug delivery of poorly soluble active pharmaceutical ingredients. They are also biocompatible in nature which makes them a promising candidate for various therapeutic applications, including drug formulations, drug delivery and other biomedical uses. The development and utilization of TheDES shows significant advancement in pharmaceutical research, providing new opportunities for improving drug delivery.

METHODS

The current study was carried out by conducting a systematic literature review that identified relevant papers from indexed databases. Numerous studies and research are cited and quoted in this article to demonstrate the effectiveness of TheDES in enhancing drug solubility, permeability, and delivery. All chosen articles were selected considering their significance, quality, and approach to addressing issues.

RESULT

As a result, various TheDES were identified that can be formulated in different ways: one component can act as a vehicle for an API, either HBD or HBA can be an API, both HBD and HBA can be APIs, or the individual components of DES are not therapeutically active but the resulting DES possesses therapeutic activity. Additionally, TheDES were also recognized to enhance drug delivery and solubility for different APIs, including NSAIDs, anesthetic drugs, antifungals, and others.

Multifunctional Deep Eutectic Solvent-Based Microemulsion for Transdermal Delivery of Artemisinin

As a serious public health issue, malaria threatens the health of millions of people. Artemisinin, a gift from traditional Chinese medicine, has been used in the treatment of malaria and has shown good therapeutic efficiency. However, due to its low solubility, poor bioavailability, and short half-life time, some smart delivery strategies are still required. Herein, a multifunctional DES prepared from ibuprofen and menthol was prepared. This DES was shown to efficiently promote the solubility of artemisinin up to 400-fold. Then, it was further applied as the oil phase to construct an O/W microemulsion with the help of Tween-80 + Span-20 mixed surfactants. The prepared microemulsion displayed high efficiency in improving the permeability of artemisinin, which can be ascribed to the presence of the permeation enhancer menthol in DES and the microstructure of the O/W microemulsion. Moreover, the simultaneous permeation of artemisinin and ibuprofen further indicated the potential benefits of the presented formulation in the treatment of malaria. To sum up, the microemulsion based on multifunctional DES presented herein provided an effective method for transdermal delivery of artemisinin.

Effect of Mexican Propolis on Wound Healing in a Murine Model of Diabetes Mellitus

Diabetes mellitus (DM) affects the wound healing process, resulting in impaired healing or aberrant scarring. DM increases reactive oxygen species (ROS) production, fibroblast senescence and angiogenesis abnormalities, causing exacerbated inflammation accompanied by low levels of TGF-β and an increase in Matrix metalloproteinases (MMPs). Propolis has been proposed as a healing alternative for diabetic patients because it has antimicrobial, anti-inflammatory, antioxidant and proliferative effects and important properties in the healing process. An ethanolic extract of Chihuahua propolis (ChEEP) was obtained and fractionated, and the fractions were subjected to High-Performance Liquid Chromatography with diode-array (HPLC-DAD), High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) and Gas Chromatography-Mass Spectrometry (GC-MS) analyses and 46 compounds were detected. Deep wounds were made in a murine DM model induced by streptozotocin, and the speed of closure and the wound tensile strength were evaluated by the tensiometric method, which showed that ChEEP had similar activity to Recoveron, improving the speed of healing and increasing the wound tensile strength needed to open the wound again. A histological analysis of the wounds was performed using H&E staining, and when Matrix metalloproteinase 9 (MMP9) and α-actin were quantified by immunohistochemistry, ChEEP was shown to be associated with improved histological healing, as indicated by the reduced MMP9 and α-actin expression. In conclusion, topical ChEEP application enhances wound healing in diabetic mice.

Ligand-Independent Activation of Aryl Hydrocarbon Receptor and Attenuation of Glutamine Levels by Natural Deep Eutectic Solvent

Natural deep eutectic solvents (NADESs) are emerging sustainable alternatives to conventional organic solvents. Beyond their role as laboratory solvents, NADESs are increasingly explored in drug delivery and as therapeutics. Their increasing applications notwithstanding, our understanding of how they interact with biomolecules at multiple levels - metabolome, proteome, and transcriptome - within human cell remain poor. Here, we deploy integrated metabolomics, proteomics, and transcriptomics to probe how NADESs perturb the molecular landscape of human cells. In a human cell line model, we found that an archetypal NADES derived from choline and geranic acid (CAGE) significantly altered the metabolome, proteome, and transcriptome. CAGE upregulated indole-3-lactic acid and 4-hydroxyphenyllactic acid levels, resulting in ligand-independent activation of aryl hydrocarbon receptor to signal the transcription of genes with implications for inflammation, immunomodulation, cell development, and chemical detoxification. Further, treating the cell line with CAGE downregulated glutamine biosynthesis, a nutrient rapidly proliferating cancer cells require. CAGE's ability to attenuate glutamine levels is potentially relevant for cancer treatment. These findings suggest that NADESs, even when derived from natural components like choline, can indirectly modulate cell biology at multiple levels, expanding their applications beyond chemistry to biomedicine and biotechnology.

Deep Eutectic Solvents: An Eco-friendly Design for Drug Engineering

In the spirit of circular economy and sustainable chemistry, the use of environmentally friendly chemical products in pharmacy has become a hot topic. In recent years, organic solvents have been the subject of a great range of restriction policies due to their harmful effects on the environment and toxicity to human health. In parallel, deep eutectic solvents (DESs) have emerged as suitable greener solvents with beneficial environmental impacts and a rich palette of physicochemical advantages related to their low cost and biocompatibility. Additionally, DESs can enable remarkable solubilizing effect for several active pharmaceutical ingredients (APIs), thus forming therapeutic DESs (TheDESs). In this work, special attention is paid to DESs, presenting a precise definition, classification, methods of preparation, and characterization. A description of natural DESs (NaDESs), i. e., eutectic solvents present in natural sources, is also reported. Moreover, the present review article is the first one to detail the different approaches for judiciously selecting the constituents of DESs in order to minimize the number of experiments. The role of DESs in the biomedical and pharmaceutical sectors and their impact on the development of successful therapies are also discussed.

Untapped Potential of Deep Eutectic Solvents for the Synthesis of Bioinspired Inorganic-Organic Materials

Since the discovery of deep eutectic solvents (DESs) in 2003, significant progress has been made in the field, specifically advancing aspects of their preparation and physicochemical characterization. Their low-cost and unique tailored properties are reasons for their growing importance as a sustainable medium for the resource-efficient processing and synthesis of advanced materials. In this paper, the significance of these designer solvents and their beneficial features, in particular with respect to biomimetic materials chemistry, is discussed. Finally, this article explores the unrealized potential and advantageous aspects of DESs, focusing on the development of biomineralization-inspired hybrid materials. It is anticipated that this article can stimulate new concepts and advances providing a reference for breaking down the multidisciplinary borders in the field of bioinspired materials chemistry, especially at the nexus of computation and experiment, and to develop a rigorous materials-by-design paradigm.

Cannabidiol-Loaded Lipid-Stabilized Nanoparticles Alleviate Psoriasis Severity in Mice: A New Approach for Improved Topical Drug Delivery

Cannabidiol (CBD) is a promising natural agent for treating psoriasis. CBD activity is attributed to inhibition of NF-kB, IL-1β, IL-6, and IL-17A. The present study evaluated the anti-psoriatic effect of cannabidiol in lipid-stabilized nanoparticles (LSNs) using an imiquimod (IMQ)-induced psoriasis model in mice. CBD-loaded LSNs were stabilized with three types of lipids, Cetyl alcohol (CA), Lauric acid (LA), and stearic-lauric acids (SALA), and were examined in-vitro using rat skin and in-vivo using the IMQ-model. LSNs loaded with coumarin-6 showed a localized penetration depth of about 100 µm into rat skin. The LSNs were assessed by the IMQ model accompanied by visual (psoriasis area severity index; PASI), histological, and pro-psoriatic IL-17A evaluations. Groups treated with CBD-loaded LSNs were compared to groups treated with CBD-containing emulsion, unloaded LSNs, and clobetasol propionate, and to an untreated group. CBD-loaded LSNs significantly reduced PASI scoring compared to the CBD emulsion, the unloaded LSNs, and the untreated group (negative controls). In addition, SALA- and CA-containing nanoparticles significantly inhibited IL-17A release, showing a differential response: SALA > CA > LA. The data confirms the effectiveness of CBD in psoriasis therapy and underscores LSNs as a promising platform for delivering CBD to the skin.

Effect of Deep Eutectic System (DES) on Oral Bioavailability of Celecoxib: In Silico, In Vitro, and In Vivo Study

Different deep eutectic systems (DES) of choline chloride (CC)-urea (UA) (1:2), CC-glycerol (GLY) (1:2), CC-malonic acid (MA) (1:1), and CC-ascorbic acid (AA) (2:1) were generated and characterized by polarized light microscope (PLM) and Fourier transform infrared spectroscope (FTIR). The equilibrium solubility of celecoxib (CLX) in DES was compared to that in deionized water. The CC-MA (1:1) system provided ~10,000 times improvement in the solubility of CLX (13,114.75 µg/g) and was used for the generation of the CLX-DES system. The latter was characterized by PLM and FTIR to study the microstructure and intermolecular interaction between the CLX and CC-MA (1:1) DES. FTIR demonstrated the retention of the chemical structure of CLX. In vitro drug release studies in FaSSIF initially demonstrated high supersaturation, which decreased by ~2 fold after 2 h. Density functional theory (DFT)-based calculations provided a molecular-level understanding of enhanced solubility. Gibbs free energy calculations established the role of the strongest binding of CLX with CC and MA. A phase solubility study highlighted the role of hydrotropy-induced solubilization of the CLX-DES system. Animal pharmacokinetic studies established 2.76 times improvement in Cmax, 1.52 times reduction in tmax, and 1.81 times improvement in AUC0-∞. The overall results demonstrated the potential of developing a DES-based supersaturating drug-delivery system for pharmaceutical loading of drugs having solubility and dissolution rate-limited oral bioavailability.

Hydrophobic DES Based on Menthol and Natural Organic Acids for Use in Antifouling Marine Coatings

Marine biofouling negatively impacts industries with off-shore infrastructures, such as naval, oil, and aquaculture. To date, there are no ideal sustainable, economic, and environmentally benign solutions to deal with this phenomenon. The advances achieved in green solvents, as well as its application in different industries, such as pharmaceutical and biotechnology, have promoted the emergence of deep eutectic systems (DES). These eutectic systems have applications in various fields and can be revolutionary in the marine-based industrial sector. In this study, the main objective was to investigate the potential use of hydrophobic DES (HDES) based on menthol and natural organic acids for their use as marine antifouling coatings. Our strategy encompassed the physicochemical characterization of different formulations, which allowed us to identify the most appropriate molar ratio and intermolecular interactions for HDES formations. The miscibility of the resulting HDES with the marine coating has been evaluated and proven to be successful. The Men/OL (1:1) system proved to be the most promising in terms of cost-production and thus was the one used in subsequent antifouling tests. The cytotoxicity of this HDES was evaluated using an in vitro cell model (HaCat cells) showing no significant toxicity. Furthermore, the application of this system incorporated into coatings that are used in marine structures was also studied using marine species (Mytilus edulis mussels and Patella vulgata limpets) to evaluate both their antifouling and ecotoxicity effects. HDES Men/OL (1:1) incorporated in marine coatings was promising in reducing marine macrofouling and also proved to be effective at the level of microfouling without viability impairment of the tested marine species. It was revealed to be more efficient than using copper oxide, metallic copper, or ivermectin as antifouling agents. Biochemical assays performed on marine species showed that this HDES does not induce oxidative stress in the tested species. These results are a strong indication of the potential of this HDES to be sustainable and efficiently used in marine fouling control technologies.

T-2 toxin induces dermal inflammation and toxicity in mice: The healing potential of menthol

According to the World Health Organization and the Food and Agricultural Organization of the United Nations, T-2 is one of the most harmful food-toxic chemicals, penetrates intact skin. The current study examined the protective benefits of menthol topical treatment on T-2 toxin-induced cutaneous toxicity in mice. Lesions were observed on the skin of the T-2 toxin-treated groups at 72 and 120 h. The T-2 toxin (2.97 mg/kg/bw)-treated group developed skin lesions, skin inflammation, erythema, and necrosis of skin tissue in contrast to the control group. Our findings reveal that topical application of 0.25% and 0.5% MN treated groups resulted in no erythema or inflammation, and normal skin was observed with growing hairs. The 0.5% MN administered group demonstrated an 80% blister and erythema healing effect in in vitro tests. In addition, MN dose-dependently suppressed ROS and lipid peroxidation mediated by the T-2 toxin up to 120%. Histology discoveries and the immunoblotting investigations with the downregulation of i-NOS gene expression confirmed the validity of menthol activity. Further molecular docking experiments of menthol against the i-NOS protein demonstrated stable binding efficacy with conventional hydrogen bond interactions, indicating compelling evidence of menthol's anti-inflammatory effects on the T-2 toxin-induced skin inflammation.

Food-Waste Valorisation: Synergistic Effects of Enabling Technologies and Eutectic Solvents on the Recovery of Bioactives from Violet Potato Peels

The recovery of valuable bioactive compounds from the main underutilised by-products of the food industry is one of the greatest challenges to be addressed in circular economy. Potato peels are the largest waste generated during potato processing. However, they could be a potential source of valuable bioactive compounds, such as polyphenols, that can be reused as natural antioxidants. Currently, environmentally benign enabling technologies and new types of non-toxic organic solvents for the extraction of bioactive compounds may dramatically improve the sustainability of these processes. This paper focuses on the potential inherent in the valorisation of violet potato peels (VPPs) by recovering antioxidants using natural deep eutectic solvents (NaDES) under ultrasound (US)- and microwave (MW)-assisted extraction. Both the enabling technologies provided performances that were superior to those of conventional extractions in terms of antioxidant activity determined by the DPPH· (2,2-diphenyl-1-picrylhydrazyl) assay. In particular, the most promising approach using NaDES is proven to be the acoustic cavitation with a Trolox eq. of 1874.0 mmolTE/gExtr (40 °C, 500 W, 30 min), vs. the 510.1 mmolTE/gExtr of hydroalcoholic extraction (80 °C, 4 h). The shelf-life of both hydroalcoholic and NaDES-VPPs extracts have been assessed over a period of 24 months, and found that NaDES granted a 5.6-fold shelf-life extension. Finally, the antiproliferative activity of both hydroalcoholic and NaDES-VPPs extracts was evaluated in vitro using the MTS assay on human tumour Caco-2 cells and normal human keratinocyte cells (HaCaT). In particular, NaDES-VPPs extracts exhibited a significantly more pronounced antiproliferative activity compared to the ethanolic extracts without a noteworthy difference between effects on the two cell lines.

Deep Eutectic Solvents Comprising Organic Acids and Their Application in (Bio)Medicine

Over the last years, we observed a significant increase in the number of published studies that focus on the synthesis and characterization of deep eutectic solvents (DESs). These materials are of particular interest mainly due to their physical and chemical stability, low vapor pressure, ease of synthesis, and the possibility of tailoring their properties through dilution or change of the ratio of parent substances (PS). DESs, considered as one of the greenest families of solvents, are used in many fields, such as organic synthesis, (bio)catalysis, electrochemistry, and (bio)medicine. DESs applications have already been reported in various review articles. However, these reports mainly described these components' basics and general properties without focusing on the particular, PS-wise, group of DESs. Many DESs investigated for potential (bio)medical applications comprise organic acids. However, due to the different aims of the reported studies, many of these substances have not yet been investigated thoroughly, which makes it challenging for the field to move forward. Herein, we propose distinguishing DESs comprising organic acids (OA-DESs) as a specific group derived from natural deep eutectic solvents (NADESs). This review aims to highlight and compare the applications of OA-DESs as antimicrobial agents and drug delivery enhancers-two essential fields in (bio)medical studies where DESs have already been implemented and proven their potential. From the survey of the literature data, it is evident that OA-DESs represent an excellent type of DESs for specific biomedical applications, owing to their negligible cytotoxicity, fulfilling the rules of green chemistry and being generally effective as drug delivery enhancers and antimicrobial agents. The main focus is on the most intriguing examples and (where possible) application-based comparison of particular groups of OA-DESs. This should highlight the importance of OA-DESs and give valuable clues on the direction the field can take.

Wearable Smart Bandage-Based Bio-Sensors

Bandage is a well-established industry, whereas wearable electronics is an emerging industry. This review presents the bandage as the base of wearable bioelectronics. It begins with introducing a detailed background to bandages and the development of bandage-based smart sensors, which is followed by a sequential discussion of the technical characteristics of the existing bandages, a more practical methodology for future applications, and manufacturing processes of bandage-based wearable biosensors. The review then elaborates on the advantages of basing the next generation of wearables, such as acceptance by the customers and system approvals, and disposal.

Ecotoxicological study of glucose:choline chloride and sorbitol:choline chloride at different contents of water

The search of new solvents is currently focused on deep eutectic solvents (DES). However, there are not many ecotoxicological studies in different biomodels of DES that allow knowing how these chemicals affect to the environment along the trophic chain. In this manuscript, two DES at different proportion of water have been prepared and characterized from the ecotoxicological point of view. These solvents are glucose:choline chloride (2:5) and sorbitol:choline chloride (3:2) at different contents of water. To carry out the ecotoxicological study, three biomodels have been used: bacteria Aliivibrio fisheri (A. fisheri), crustacean Daphnia magna (D. magna) and algae Raphidocelis subcapitata (R. subcapitata). The obtained results show that the ecotoxicity of these chemicals depends on the biomodel used and the amount of water, being toxicity values lower for chemicals with higher water content. However, it is important to highlight that the ecotoxicity for all chemicals is quite low with effective concentrations, EC₅₀ values above 1000 mg/L in all the studied cases.

Oxymatrine-fatty acid deep eutectic solvents as novel penetration enhancers for transdermal drug delivery: formation mechanism and enhancing effect

Transdermal delivery of drugs is commonly limited by low skin permeability. The aim of the study was to synthesize deep eutectic solvents (DESs) based on oxymatrine (OMT) and fatty acids with various alkyl chain lengths (LCFAs) as novel vehicles, to solubilize the water-insoluble drug and enhance percutaneous penetration. Quercetin (QUE) was selected as a model drug. Combining differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and molecular simulations demonstrated that the formation of DESs was mediated by charge-assisted hydrogen bonding. Physicochemical properties including stability, viscosity, and solubilization capacity were also studied. Subsequently, the effect of three stable DESs on drug release and skin permeability was evaluated. The results showed that QUE was solubilized well and presented a different sustained release behavior in DESs. Meanwhile, DESs enhanced the skin permeation of OMT and QUE, which was influenced by alkyl chain lengths of LCFAs, whereas DES consisting of lauric acid (LA) exhibited the highest enhancing effect. FTIR, DSC, and molecular docking further demonstrated consistency between micro molecular mechanism and macro penetration behavior. Additionally, HaCaT cells treated with DESs showed high cell viability, suggesting their good skin safety. Taken together, OMT-LCFA DESs would be a promising penetration enhancer for transdermal drug delivery, which also provides guidance for the design of new DESs.

The effect of peppermint oil addition on the physical stability, irritability, and penetration of nanostructured lipid carrier coenzyme Q10

Background: Coenzyme Q10 is formulated into Nanostructured Lipid Carrier (NLC) added with peppermint oil (PO) 0% (F1), 1% (F2), 1.5% (F3) and 2% (F4) to increase its penetration. Objective: This study aims to determine the effect of PO addition on the irritability, stability, and penetration of Coenzyme Q10 in the NLC. Methods: Coenzyme Q10 NLC was prepared using the High Shear Homogenization method. Furthermore, physical characterization was carried out. Physical stability testing was carried out for 90 days at a temperature of 25±5oC and an RH of 60±10%. The in vivo irritation test was observed for mice’s back skin after 24 hours while the penetration study was further evaluated at 2 hours of the sample application. Results: Increasing the PO amount into Coenzyme Q10 NLC reduced the viscosity which was 329.1±15.5 cps for PO 0% to 219.9±2.9 cps for 2% addition. The observation of particle morphology showed that all NLC Coenzyme Q10 has a spherical particle shape with particle size between 188.25±13.22 to 197.80±14.19 nm. All formulas had high entrapment efficiency (>80%). PO addition did not cause changes in physical characteristics during 90 days of storage. The 24 hours’ irritation test showed that F2 and F3 are non-irritating. By PO addition skin penetration improved at 2 hours’ penetration study. Conclusion: PO addition up to 2% reduced viscosity, but did not affect particle size and morphology of Coenzyme Q10 NLC. Addition of PO up to 1.5% increased entrapment efficiency, did not irritate and increased the penetration of Coenzyme Q10 NLC.

Therapeutic Deep Eutectic Solvents: A Comprehensive Review of Their Thermodynamics, Microstructure and Drug Delivery Applications

Deep eutectic solvents (DES) are multicomponent liquids that are usually formed by coupling a hydrogen bond donor and acceptor leading to strong non-covalent (NC) intermolecular networking and profound depression in the melting point of the system. Pharmaceutically, this phenomenon has been exploited to improve drugs' physicochemical properties, with an established DES therapeutic subcategory, therapeutic deep eutectic solvents (THEDES). THEDES preparation is usually via straightforward synthetic processes with little involvement of sophisticated techniques, which, in addition to its thermodynamic stability, make these multi-component molecular adducts a very attractive alternative for drug enabling purposes. Other NC bonded binary systems (e.g., co-crystals and ionic liquids) are utilized in the pharmaceutical field for enhancing drug's behaviours. However, a clear distinction between these systems and THEDES is scarcely discussed in the current literature. Accordingly, this review provides a structure-based categorization for DES formers, a discussion of its thermodynamic properties and phase behaviour, and it clarifies the physicochemical and microstructure boundaries between DES and other NC systems. Additionally, a summary of its preparation techniques and their experimental conditions preparation is supplied. Instrumental analysis techniques can be used to characterize and differentiate DES from other NC mixtures, hence this review draws a road map to for this purpose. Since this work mainly focuses on pharmaceutical applications of DES, all types of THEDES including the highly discussed types (conventional, drugs dissolved in DES and polymer based) in addition to the less discussed categories are covered. Finally, the regulatory status of THEDES was investigated despite the current unclear situation.

Menthol-based deep eutectic systems as antimicrobial and anti-inflammatory agents for wound healing

Effective antimicrobial treatment has been identified as a serious and unmet medical need. Herein, we present a strategy based on deep eutectic systems (DES) to overcome current limitations, answering the need not only to effectively kill bacterial agents but also to avoid their adhesion and proliferation, which is associated with biofilm formation and have a crucial impact on bacterial virulence. To achieve such a goal, natural deep eutectic systems (NADES) based on menthol (Me) and saturated free fatty acids (FFA) were produced, fully physicochemical characterized, and its bioactive properties were described. The antimicrobial potential of menthol-based NADES with FFA, namely, myristic acid (MA), lauric acid (LA), and stearic acid (SA) were investigated towards a broad panel of microorganisms. The obtained data indicates that NADES possess effective antimicrobial properties towards the Gram-positive bacterial and fungal strains tested. Among the tested formulations, Me:LA at a molar ratio of 4:1 molar was used to carry out a biofilm detachment/removal assay due to is superior microbiological properties. This formulation was able to effectively lead to biofilm removal/dispersion of not only methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans, but also Escherichia coli, without the need of any additional physical force or antibiotic. Furthermore, since microbial invasion and biofilm formation is highly undesired in wound healing, namely in chronic wound healing, the wound healing properties of these eutectic formulations was also investigated. The results suggest that these NADES can cope with microbial invasion and biofilm detachment while not compromising normal keratinocyte proliferation and migration verified in wound healing and epidermis repair, while also contributing to the reduction of cell stress and inflammation via the control of ROS production. In conclusion, these results provide the indication that NADES based on Me and FFA holds great interest as antimicrobial agents for preventive and therapeutic applications in various clinical settings, including wound healing.

Menthol and Fatty Acid-Based Hydrophobic Deep Eutectic Solvents as Media for Enzyme Activation

This research aims to provide insights into the biological efficacy of a newly formed hydrophobic deep eutectic solvent (DES). A DES based on menthol was successfully synthesized with fatty acids. The DESs’ properties as enzyme activators were examined against a neat counterpart. The menthol:decanoic acid (1:1) combination showed improved thermal stability, strong catalytic activity, and reusability for up to four subsequent cycles under ideal conditions (pH 7.0, 40 °C for 2 h). The hydrophobic DES replaced hexane in ester synthesis, where RNL@DES5 showed better fatty acid conversion compared to neat RNL. This study demonstrated promising applications of hydrophobic DESs in non-aqueous organic reactions.

In Vitro and In Vivo Characterization Methods for Evaluation of Modern Wound Dressings

Chronic wound management represents a major challenge in the healthcare sector owing to its delayed wound-healing process progression and huge financial burden. In this regard, wound dressings provide an appropriate platform for facilitating wound healing for several decades. However, adherent traditional wound dressings do not provide effective wound healing for highly exudating chronic wounds and need the development of newer and innovative wound dressings to facilitate accelerated wound healing. In addition, these dressings need frequent changing, resulting in more pain and discomfort. In order to overcome these issues, a wide range of affordable and innovative modern wound dressings have been developed and explored recently to accelerate and improve the wound healing process. However, a comprehensive understanding of various in vitro and in vivo characterization methods being utilized for the evaluation of different modern wound dressings is lacking. In this context, an overview of modern dressings and their complete in vitro and in vivo characterization methods for wound healing assessment is provided in this review. Herein, various emerging modern wound dressings with advantages and challenges have also been reviewed. Furthermore, different in vitro wound healing assays and in vivo wound models being utilized for the evaluation of wound healing progression and wound healing rate using wound dressings are discussed in detail. Finally, a summary of modern wound dressings with challenges and the future outlook is highlighted.

Controversy on the toxic nature of deep eutectic solvents and their potential contribution to environmental pollution

Deep eutectic solvents (DES) are promising reaction media where interesting catalytic processes can be carried out. In theory, most of these mixtures are environmentally friendly, being an alternative to traditionally pollutant organic solvents used in several processes related to organic chemistry and biotechnology. However, recent studies show contradictory results regarding their toxicity. The method selected to perform toxicity studies could be significantly conditioned by some of the physical properties displayed by the DESs. Also, the metabolic capabilities of the organisms/cells used to monitor their toxicity are influenced by their physical properties. In this review, relevant physical-chemical properties for toxicity studies are summarized. The advantages/disadvantages of the used tests to monitor their toxicity and biodegradability in connection with the chosen organisms/cells are discussed, shedding light on their limitations. These findings could be taken as a starting point for designing more accurate DESs toxicity studies covering a wider spectrum of organisms and cells to be used as biomodels to monitor environmental pollution caused by DESs.

A review on potential of green solvents in hydrothermal liquefaction (HTL) of lignin

One of the greatest challenges in biorefinery is to reduce biomass' recalcitrance and enable valorization of lignin into higher value compounds. Likewise, green solvents and hydrothermal liquefaction (HTL) with feasible economic viability, functionality, and environmental sustainability have been widely introduced in extraction and conversion of lignin. This review starts with the underscore of disadvantages and limitations of conventional pretreatment approaches and role of green solvents in lignin extraction. Subsequently, the effect of process parameters along with the reaction mechanisms and kinetics on conversion of lignin through HTL were comprehensively reviewed. The limitations of green solvents in extraction and HTL of lignin from biomass were discussed based on the current advancements of the field and future research scopes were also proposed. More details info on HTL of biomass derived lignin which avoid the energy-intensive drying procedures are crucial for the accelerated development and deployment of the advanced lignin biorefinery.

Extraction of curcuminoids and ar-turmerone from turmeric (Curcuma longa L.) using hydrophobic deep eutectic solvents (HDESs) and application as HDES-based microemulsions

The extraction of curcuminoids and aromatic (ar)-turmerone from Curcuma longa L. using organic solvents produces chemical waste, and is therefore incompatible with food applications. To address this issue, this study presents the design of hydrophobic deep eutectic solvents (HDESs) and HDES-based microemulsions. Using the response surface methodology (RSM), the optimal extraction conditions were identified as follows: HDES = OA:menthol (1:3.6 M ratio), solid-to-liquid ratio = 10:1 (mg/mL), and extraction duration = 90 min (prediction accuracy ≥ 85 %). Under these conditions, the HDES extraction yields of bisdemethoxycurcumin, demethoxycurcumin, curcumin, and ar-turmerone were 2.49 ± 0.25, 5.61 ± 0.45, 9.40 ± 0.86, and 3.83 ± 0.19 % (w/w, dry basis), respectively, while those obtained using the HDES-based microemulsion were 2.10 ± 0.18, 6.31 ± 0.48, 12.6 ± 1.20, and 2.58 ± 0.19 % (w/w, dry basis), respectively. The HDES and its microemulsions are more effective and environmentally friendly than conventional organic solvents for the extraction of curcuminoids and ar-turmerone, and these solvents are also compatible with food and pharmaceutical formulations.

Natural Deep Eutectic Solvents Based on Choline Chloride and Phenolic Compounds as Efficient Bioadhesives and Corrosion Protectors

Natural deep eutectics solvents (NADES), owing to their high solvation capacity and nontoxicity, are actively being sought for many technological applications. Herein, we report a series of novel NADES based on choline chloride and plant-derived polyphenols. Most of the obtained phenolic NADES have a wide liquid range and high thermal stability above 150 °C. Among them, small-sized polyphenols, like pyrogallol, vanillyl alcohol, or gentisic acid, lead to low-viscosity liquids with ionic conductivities in the order of 10^-3 S cm^-1 at room temperature. Interestingly, polyphenols possess valuable properties as therapeutic agents, antioxidants, adhesives, or redox-active compounds, among others. Thus, we evaluated the potential of these novel NADES for two applications: bioadhesives and corrosion protection. The mixture of choline chloride-vanillyl alcohol (2:3 mol ratio) and gelatin resulted in a highly adhesive viscoelastic liquid (adhesive stress ≈ 135 kPa), affording shear thinning behavior. Furthermore, choline chloride-tannic acid (20:1) showed an extraordinary ability to coordinate iron ions, reaching excellent corrosion inhibitive efficiencies in mild steel protection.

Thermally switchable, crystallizable oil and silicone composite adhesives for skin-interfaced wearable devices

Continuous health monitoring is essential for clinical care, especially for patients in neonatal and pediatric intensive care units. Monitoring currently requires wired biosensors affixed to the skin with strong adhesives that can cause irritation and iatrogenic injuries during removal. Emerging wireless alternatives are attractive, but requirements for skin adhesives remain. Here, we present a materials strategy enabling wirelessly triggered reductions in adhesive strength to eliminate the possibility for injury during removal. The materials involve silicone composites loaded with crystallizable oils with melting temperatures close to, but above, surface body temperature. This solid/liquid phase transition occurs upon heating, reducing the adhesion at the skin interface by more than 75%. Experimental and computational studies reveal insights into effects of oil mixed randomly and patterned deterministically into the composite. Demonstrations in skin-integrated sensors that include wirelessly controlled heating and adhesion reduction illustrate the broad utility of these ideas in clinical-grade health monitoring.

Therapeutic hydrophobic deep eutectic solvents of menthol and fatty acid for enhancing anti-inflammation effects of curcuminoids and curcumin on RAW264.7 murine macrophage cells

Owing to their water insolubility, low stability, and poor absorption, anti-inflammatory curcuminoids (CUN) are difficult to be extracted and delivered to the action site. As a result, therapeutic hydrophobic deep eutectic solvents (HDESs), containing menthol and fatty acids (capric, caprylic, and oleic acids), are being developed for CUN solubilization and delivery. In this study, the anti-inflammatory effects of various combinations of HDESs with CUN and curcumin (CUR) were investigated on RAW264.7 macrophage cells. The results showed that CUN can be solubilized using the HDESs. The HDESs of oleic acid (OLA) : menthol (1 : 2, 1 : 1, and 2 : 1 molar ratios) exhibited anti-inflammatory effects, and OLA : menthol (1 : 1 molar ratio) increased the anti-inflammatory effects of CUR. The cytotoxicity of CUN and CUR was also lowered when combined with some OLA : menthol HDESs. The combination of OLA, menthol, and CUR entirely suppressed NO secretion without significant cytotoxicity. These results clearly indicate the potential of HDESs to solubilize CUN and impart anti-inflammatory properties. Furthermore, these solvents could replace organic solvents for CUN extraction, with the added benefit of being therapeutic, biodegradable, and safe for human consumption.