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Deep eutectic solvents (DESs) are an emerging class of green solvents with a wide spectrum of potential applications whose properties may be further tailored through the addition of water. Here, we study, through molecular dynamics, the influence of water on the properties of a betaine-glycerol-water (B:G:W) DES (1:2:ζ; ζ = 0 to 100), aiming at getting insight into the structural and dynamic crossover between a DES and an aqueous solution. The density, shear viscosity, and diffusion coefficients are found to exhibit a non-linear dependence of ζ, similar to that observed for the solvation layers' composition. Each Gly and Bet are replaced, respectively, by ∼3 and ∼5 water molecules, with the highest rates of depletion being found for Gly around Bet and Gly around Gly. Above ζ = 7 (70 mol %; 29.5 wt %), a major structural transformation occurs, with the complete disruption of the second Bet-Gly solvation layer and the formation of a new second layer at a shorter distance, accompanied by a sudden change in the rate of increase of the components' diffusion. Nonetheless, opposite to other DES, our results indicate a smooth crossover between a DES and an aqueous solution., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

A new methodology for the selective extraction of antioxidants from mate tea leaves (and decaffeinated mate tea leaves), using different natural deep eutectic systems (NADES), is reported in this paper. A fractionated extraction was carried out and the optimization of the extraction conditions such as solid/liquid ratio, temperature, time, stirring and the use of ultrasound assisted extraction (UAE) technology was performed. The results demonstrate that a sequential extraction using, in a first step, an hydrophobic system Men:Lau (2:1) and, in a second step, an hydrophilic lactic acid-based NADES, leads to two distinct extracts: the first one rich in pigments and the second one rich in polyphenols. NADES systems were able to extract 30% more of the polyphenolic components of the mate tea leaves matrices, when compared with traditional solvents/techniques. Moreover, it has been shown that the incorporation of the extract in the NADES, compared to the same extract in aqueous medium was beneficial for the stabilization of the antioxidants. It maintains their functionality at least for three months, reaching 41% more versus the extracts obtained by traditional solvents/techniques. The absence of caffeine in the extracts did not shown to have any effects on the stability results., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors.)

The demand for tissue and organ transplantation worldwide has led to an increased interest in the development of new therapies to restore normal tissue function through transplantation of injured tissue with biomedically engineered matrices. Among these developments is decellularization, a process that focuses on the removal of immunogenic cellular material from a tissue or organ. However, decellularization is a complex and often harsh process that frequently employs techniques that can negatively impact the properties of the materials subjected to it. The need for a more benign alternative has driven research on supercritical carbon dioxide (scCO 2 ) assisted decellularization. scCO 2 can achieve its critical point at relatively low temperature and pressure conditions, and for its high transfer rate and permeability. These properties make scCO 2 an appealing methodology that can replace or diminish the exposure of harsh chemicals to sensitive materials, which in turn could lead to better preservation of their biochemical and mechanical properties. The presented review covers relevant literature over the last years where scCO 2 -assisted decellularization is employed, as well as discussing major topics such as the mechanism of action behind scCO 2 -assisted decellularization, CO 2 and cosolvents' solvent properties, effect of the operational parameters on decellularization efficacy and on the material's properties.

The goal of the study was to establish a procedure for improving the efficiency of supercritical carbon dioxide (scCO 2 ) extraction of Origanum vulgare L. spp. hirtum (Greek oregano) and enhancing the quality of obtained extracts. Microwave and enzymatic pretreatments of the plant material were applied prior to the scCO 2 extraction. It was determined that the microwave pretreatment with irradiation power 360 W during 2 min accelerated the extraction of lipophilic compounds and provided a twofold higher extraction yield compared to the control. Moreover, this pretreatment also led to an increase in oxygenated monoterpenes content and the most dominant component carvacrol, as well as the extracts' antioxidant activity. The enzymatic pretreatment caused a significant increase in the extraction yield and the attainment of the extract with the most potent antioxidant properties. Coupling the pretreatments with scCO 2 extraction improves the process of obtaining high value lipophilic products of oregano in terms of utilization of the plant material, acceleration of the extraction with the possibility to adjust its selectivity and quality of extracts, and enhancement of biological activity.

The versatility of chitin and its derivatives has allowed their utilization in a wide range of applications, from wastewater treatment to pharmaceutical or biomedical industries. However, even though the extraction method used industrially is extremely efficient, it involves the use of strong acids and bases and results in the disposal of large quantities of toxic effluents. Deep eutectic systems (DESs) have emerged as a promising new class of alternative solvents, including for chitin recovery. Yet, the assessment of their toxicity has often been neglected. Therefore, in this work, the phytotoxicity of choline chloride (ChCl)/organic acid-based DESs toward wheat seeds was evaluated by measuring different growth parameters and stress biomarkers. DESs were then explored for the efficient recovery of chitin contained in brown crab shell residues at varying conditions of temperature and processing time as well as with and without water addition. The obtained chitin was then characterized through different analytical techniques and compared to a standard as well as to chitin obtained by a conventional acid/alkaline hydrolysis. Results have shown that by applying a ChCl/lactic acid-based DES (which was the system that showed the least phytotoxic effects on wheat; EC50 ≥ 1.6 mg/mL) at 130 °C, it was possible to obtain pure chitin (up to 98%) with characteristics similar to those presented by commercial chitin or chitin recovered by conventional hydrolysis in a shorter time (more than 8-fold faster), thus suggesting that ChCl/organic acid-based DESs can truly represent a low-phytotoxic alternative extraction media for the recovery of chitin from the crab shell biomass., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Deep eutectic solvents have been recently reported as an interesting alternative to improve the therapeutic efficacy of conventional drugs, hence called therapeutic deep eutectic solvents (THEDES). The main objective of this work was to evaluate the potential of limonene (LIM) based THEDES as new possible systems for cancer treatment. LIM is known to have antitumor activity, however it is highly toxic and cell viability is often compromised, thus this compound is not selective towards cancer cells. Different THEDES based on LIM were developed to unravel the anticancer potential of such systems. THEDES were prepared by gently mixing saturated fatty acids menthol or ibuprofen (IBU) with LIM. Successful THEDES were obtained for Menthol:LIM (1:1), CA:LIM (1:1), IBU:LIM (1:4) and IBU:LIM(1:8). The results indicate that all the THEDES present antiproliferative properties, but IBU:LIM (1:4) was the only formulation able to inhibit HT29 proliferation without comprising cell viability. Therefore, IBU:LIM (1:4) was the formulation selected for further assessment of anticancer properties. The results suggest that the mechanism of action of LIM:IBU (1:4) is different from isolated IBU and LIM, which suggest the synergetic effect of DES. In this work, we unravel a methodology to tune the selectivity of LIM towards HT29 cell line without compromising cell viability of healthy cells. We demonstrate furthermore that coupling LIM with IBU leads also to an enhancement of the anti-inflammatory activity of IBU, which may be important in anti-cancer therapies.

Platelet lysates (PLs) are a natural source of growth factors (GFs) known for its stimulatory role on stem cells which can be obtained after activation of platelets from blood plasma. The possibility to use PLs as growth factor source for tissue healing and regeneration has been pursued following different strategies. Platelet lysates are an enriched pool of growth factors which can be used as either a GFs source or as a three-dimensional (3D) hydrogel. However, most of current PLs-based hydrogels lack stability, exhibiting significant shrinking behavior. This chapter focuses on the application of supercritical fluid technology to develop three-dimensional architectures of PL constructs, crosslinked with genipin. The proposed technology allows in a single step operation the development of mechanically stable porous structures, through chemical crosslinking of the growth factors present in the PL pool, followed by supercritical drying of the samples. Furthermore gradient structures of PL-based structures with bioactive glass are also presented and are described as an interesting approach to the treatment of osteochondral defects.

Fast-dissolving delivery systems (FDDS) have received increasing attention in the last years. Oral drug delivery is still the preferred route for the administration of pharmaceutical ingredients. Nevertheless, some patients, e.g. children or elderly people, have difficulties in swallowing solid tablets. In this work, gelatin membranes were produced by electrospinning, containing an encapsulated therapeutic deep-eutectic solvent (THEDES) composed by choline chloride/mandelic acid, in a 1:2 molar ratio. A gelatin solution (30% w/v) with 2% (v/v) of THEDES was used to produce electrospun fibers and the experimental parameters were optimized. Due to the high surface area of polymer fibers, this type of construct has wide applicability. With no cytotoxicity effect, and showing a fast-dissolving release profile in PBS, the gelatin fibers with encapsulated THEDES seem to have promising applications in the development of new drug delivery systems.

Background: This study investigated the preparation of ordered patterned surfaces and/or microspheres from a natural-based polymer, using the breath figure and reverse breath figure methods., Methods: Poly(D,L-lactic acid) and starch poly(lactic acid) solutions were precipitated in different conditions - namely, polymer concentration, vapor atmosphere temperature and substrate - to evaluate the effect of these conditions on the morphology of the precipitates obtained., Results: The possibility of fine-tuning the properties of the final patterns simply by changing the vapor atmosphere was also demonstrated here using a range of compositions of the vapor phase. Porous films or discrete particles are formed when the differences in surface tension determine the ability of polymer solution to surround water droplets or methanol to surround polymer droplets, respectively. In vitro cytotoxicity was assessed applying a simple standard protocol to evaluate the possibility to use these materials in biomedical applications. Moreover, fluorescent microscopy images showed a good interaction of cells with the material, which were able to adhere on the patterned surfaces after 24 hours in culture., Conclusions: The development of patterned surfaces using the breath figure method was tested in this work for the preparation of both poly(lactic acid) and a blend containing starch and poly(lactic acid). The potential of these films to be used in the biomedical area was confirmed by a preliminary cytotoxicity test and by morphological observation of cell adhesion.