Acid Solvent Research Articles

Natural acidic deep eutectic solvent-mediated microwave-assisted simultaneous hydrodistillation, hydrolysis, and extraction for obtaining essential oils, gallic acid and ellagic acid from Liquidambar formosana leaves and fruits

In this study, an improved method of naturally acidic deep eutectic solvent-mediated microwave-assisted simultaneous hydrodistillation, hydrolysis, and extraction (MSHDHE) was employed to obtain essential oils, gallic acid and ellagic acid from Liquidambar formosana leaves and fruits. The obtained target analytes were then analyzed via GC‒MS and HPLC. The optimal extraction conditions were identified via a Box–Behnken design. Compared with fruits, L. formosana leaves contain more gallic acid and ellagic acid, which have more essential oils. GC‒MS analysis revealed few variations in the composition and content of L. formosana leaves and fruit essential oils. A total of 36 components in the essential oil of L. formosana leaves and 55 components in the essential oil of the fruits were detected via GC‒MS. Compared with classical hydrodistillation and microwave-assisted hydrodistillation, natural acidic deep eutectic solvents outperform conventional extraction solvents (pure water), providing a scientific foundation for the extraction of natural acid deep eutectic solvents consisting of choline chloride and natural organic acids.

The stability of PCV2 virus-like particles from mammalian cells and challenges for biotechnological applications

Porcine circovirus type 2 (PCV2) is a highly damaging pathogen for pig farming, causing significant economic losses. Despite the availability of vaccines based on different technologies, the virus steadily infects the world's pig population. In this context, virus-like particles (VLPs) constitute appealing alternatives for vaccine development as they lack the viral genome but present intact external surfaces.Using PCV2 VLPs expressed and purified from Expi293F cells, we demonstrate the potential to generate high-purity VLPs with excellent antigenic properties through biochemical, biophysical, and immunological characterization. Using different techniques, we also determined the melting temperature of these VLPs at nearly 55 °C.Furthermore, we conducted multiscale simulations of whole VLPs combined with multiple sequence analyses to provide a new perspective into the stability determinants. Computational results support our findings and underscore the importance of protein-nucleic acid interactions in stabilizing the VLP structure. Moreover, we spotted an unforeseen correlation between amino acid conservation, solvent exposure, and flexibility, revealing a link to viral assembly and immune evasion. These novel insights are crucial to guide the development of stabilized VLP for new vaccine prototypes to respond to the emergence of new PCV2 genotypes.

Comparison of extraction process, physicochemical properties, and in vitro digestion characteristics of chia seed mucilage polysaccharide.

The study explored five (acidic, alkaline, heating, ionic liquid, and urea solvent) extraction methods' effects on chia seed mucilage polysaccharide (CSM), an anionic polymeric macromolecule, regarding its physicochemical properties, structure, and digestion behavior. The results showed that extraction parameters have a considerable effect on modulating CSM properties. Significant differences emerged in the predominant chemical compositions: the carbohydrates and protein content ranged from 49.20±0.06% to 85.81±0.03%, and 3.20±0.13% to 14.57±0.30%, respectively. The structural analysis revealed that alkaline heating treatment facilitated the formation of protein-polysaccharide conjugates, resulting in reduced particle size, enhanced ζ-potential, and improved thermal stability (194.72±2.19J/g). The crystallinity of CSM varied, peaking at 42.9±0.22% without pH adjustment and heating. CSM extracted using 6M urea exhibited the lowest protein content, and crystallinity (25.50±0.09%), coupled with the highest gastrointestinal digestion rate and poorest thermal stability (with a carbohydrate degradability of 24.223±1.78% and enthalpy value of 62.82±0.32J/g). The CSM obtained under alkaline heating showed minute particles (201.1±10.35μm), the highest ζ-potential absolute value (20.95±2.28mV), and robust thermal stability (194.72±2.19J/g of enthalpy value), which is ideal for stabilizing emulsions or encapsulating thermolabile substances. Additionally, compared to monovalent cations‑sodium ions, divalent cations‑magnesium ions, is more tend to aggregate the CSM structure, resulting in larger molecular particles and a higher protein content. Elevated ionic concentration further diminished thermal stability. These findings suggest that CSM is a customizable, multi-purpose polymer that can be extracted in various ways based on the end-product requirements.

The Acidic Deep Eutectic Solvents for Starch Plasticization

The Acidic Deep Eutectic Solvents for Starch Plasticization

Fractionation of lignin from corncob with high−yield p − coumaric acid production in deep eutectic solvents followed by pyrolysis to produce monophenols

Two distinctive aromatic units, p − coumarate and ferulate, exist in corncob lignin, which have the potential to yield p − coumaric acid (pCA) and ferulic acid (FA). Although pCA and FA are primarily extracted from corncob lignin utilizing strong acids and bases, extremely acidic or alkaline conditions result in the disruption of the aromatic unit structure of the residual lignin. Herein, lactic acid coupled with choline chloride was utilized as acidic deep eutectic solvent (DES), while K2CO3 with glycerin was used as alkaline DES, thereby facilitating the extraction of pCA, FA and lignin from corncob in a mild environment. Furthermore, the differences in monophenol yields from pyrolysis of lignin were investigated. The alkaline DES exhibited a stronger extraction capacity for these acids. The yields of pCA and FA were 15.47 mg/g and 7.44 mg/g (based on the weight of corncob). Contrastively, the subsequent pyrolysis process yielded a higher amount of monophenol from the lignin extracted using acidic DES, with notably greater quantities of low methoxy phenolic monomers. This renders it a preferred option for subsequent processing into high−calorific biofuels. This work presents a straightforward and efficient strategy for the deconstruction of the lignin from corncob to enhance the utilization value of agricultural waste.

Efficient fractionation of lignin from Camellia oleifera shell by acidic deep eutectic solvent under mild conditions

In this study, ethylene glycol-oxalic acid deep eutectic system (DES) was used for delignification of Camellia oleifera shell (COS). The effects of treatment temperature and time on lignin removal rate, lignin purity and yield were investigated. At the treatment temperature and treatment time of 90 °C and 6 h, the residue rate, lignin removal rate and yield values of 42.33 %, 67.79 % and 45.84 %, respectively. The structure of lignin was ascertained by performing Fourier transform infrared spectroscopy (FT-IR) and two-dimensional nuclear magnetic resonance spectroscopy (2D HSQC NMR), the spectra of which indicated that COS lignin mainly comprises guaiacyl (G) units, followed by syringyl (S) units. Thermal analysis of lignin was conducted based on thermogravimetric analysis (TG) and differential scanning calorimetry (DSC), and the glass transition temperature of lignin was determined to be between 90 and 130 °C. The results in this study indicated that ethylene glycol-oxalic DES system can be used to facilitate the efficient delignification of COS.

A combination of acetic acid and deep eutectic solvent pretreatment on poplar for coproduction of bioethanol, bio-oil and energy recovery

This work proposed an acetic acid (AC) pre-hydrolysis and a deep eutectic solvent (DES) post-delignification strategy for efficient fractionation of hemicellulose and lignin from lignocellulosic biomass, providing an easily hydrolyzed cellulose, which could be effectively converted to ethanol through semi-simultaneous saccharification and fermentation (SSSF) process. Results showed that, 11.20 kg xylo-oligosaccharides (XOSs), 19.91 kg ethanol and 25.89 kg lignin could be produced from lignocellulosic biorefinery based on the AC-DES pretreatment of 100 kg poplar. In addition, the lignin recovered from DES showed the potential as feedstock for production of hydrocarbon enriched bio-oil by pyrolysis. Higher heating values (HHV) of 27.19 MJ/kg and 31.56 MJ/kg for oil were measured, after pyrolysis of DES lignin and DES lignin/low-density polyethylene (LDPE) with ratio of 7:3, respectively. Finally, mass balance and energy analysis revealed that, lignocellulosic biorefinery based on AC-DES combined pretreatment to co-produce XOSs, bioerthanol and DES lignin could achieve an energy recovery of 78 %.

Extraction and recovery of bioactive alkaloids from Phellodendron amurense Rupr. Using ultrasound-assisted green solvents and macroporous resins

The aim of this study is to develop a sustainable process for extracting alkaloids from Phellodendron amurense Rupr. The findings indicated that malic acid demonstrated the highest extraction capacity. Under optimized conditions, 46% acid concentration, 26.8 mL/g solvent-to-solid ratio, 33.5 min extraction time, and 80 °C extraction temperature, the extraction efficiencies of berberine and total alkaloids were 50.88 and 60.88 mg/g, respectively. Alkaloids were then recovered from the acidic extract using HPD-300 and HP-20 macroporous resins. The alkaloids content in the recovered product under optimal conditions was 68.88% and 67.20% for HPD-300 and HP-20 resins, respectively. The malic acid solvent, together with HPD-300 and HP-20 resins, has been recovered and demonstrated to be effective for recycling. In summary, a sustainable and comprehensive protocol for extracting alkaloids from P. amurense is presented here for the first time. The findings of this study establish a robust foundation for extracting alkaloids from natural sources using environmentally friendly solvents.

Construction of stable triazine porous organic polymer nanofiltration membrane for selective separation: The role of substrate on the membrane formation and separation performance

Porous organic polymers (POPs) have been regarded as potential candidates for high-performance membrane building blocks ascribed to their robust structure, tunable pore size, and high surface area. Normally, the POPs membrane possesses a POPs selective layer on the porous substrate for its real application. Numerous efforts have been paid to manipulate the POPs selective layer to enhance the separation performance, however, except from providing mechanical strength, the role of substrates in the formation and separation performance of POPs membrane receives less attention. In this work, we employed a systematic study to reveal the role of substrates in the governing POPs membrane formation by choosing substrates with diverse properties. The relationship between the properties of substrate (e.g., pore size, porosity, roughness, hydrophilicity, and surface functional groups) and the assembly structure of POPs membranes was in-detail analyzed. We found that the hydrolyzed polyacrylonitrile substrate induced a better assembly of POPs nanoparticles. Its rough surface and carboxylic functional groups created Van der Waals interactions and hydrogen bonding interactions to reinforce interfacial adhesion between the substrate and POPs selective layer, which facilitated the formation of intact and defect-free POPs membranes. The resulting POPs membrane displayed a high water permeance of 121.3 L m-2h−1 bar−1 with a congo red rejection of 98.9 %. Moreover, benefiting from the robust interfacial interactions between POPs selective layer and the substrate, the POPs membrane enabled itself to maintain structure stability under harsh environments, such as acidic, alkaline, and organic solvents. This work gives new insights to producing robust and high-performance POPs membranes.

High-Performance Photodiodes Based on In-Situ Etched PbSe Colloidal Quantum Dots with Responses Extended to 2500 nm.

The performance of PbSe colloidal quantum dot (CQD) based photodiodes with responses beyond 2000 nm was far from satisfactory and has rarely been reported. The difficulty in obtaining chemically stable large-sized PbSe CQDs was the main reason. In this work, chloride ions in weak acidic solvent were introduced to in-situ etch out the Se atoms on the surfaces of PbSe CQDs and formed a -Pb-Cl protection layer. As a result, there were no longer any easily oxidized Se atoms exposed to the ambient environment. The mechanism behind our method for stabilizing PbSe CQDs was distinct from the commonly reported ones such as attaching new adlayers directly. The photodiodes with the etched PbSe CQDs achieved 0.75 A/W responsivity at λ = 2200 nm, 0.15 V open circuit voltage and 100% internal quantum efficiency without the assist of photoconductive gains, which were the best records for PbSe-based photodiodes working beyond 2000 nm.

Dough properties and baking quality of near isogenic lines with single HMW-GS null at Glu-A1, Glu-B1 and Glu-D1 loci in soft wheat

High molecular weight glutenin subunits (HMW-GSs) encoded by the Glu-1 loci are key factors in determining wheat processing quality. However, the contributions of single HMW-GS to dough viscoelastic properties and end-use quality have not been well understood, especially in soft wheat. In this study, the kernel samples of five Near Isogenic Lines (NILs) of a soft wheat each with individual HMW-GS null were investigated. Significant lower SDS-sedimentation volume and lactic acid solvent retention capacity (SRC) were observed in the NILs, compared to the wild type (WT). Except for the NIL with Glu-D1y12 null, the other NILs were associated with significantly lower dough mixing tolerance compared to the WT. Also, the deletion of individual HMW-GS was associated with reduction in dough elasticity and strength, compared to the WT, with the exception of the Glu-A1x1 null. Moreover, Glu-B1x7 was the most important HMW-GS in determining dough mixing tolerance and elasticity. Compared to the WT, the deletions of Glu-D1x2, Glu-B1x7 and Glu-B1y8 significantly increased alveograph L, and decreased alveograph P and P/L ratios. All NILs with single HMW-GS null showed better sugar snap cookie baking quality than the WT. New germplasm and tools are identified for improving dough viscoelasticity and baking quality in soft wheat.

Comparative study of alkaline, acidic, and deep eutectic solvent pretreatments on lignocellulosic biomass for enhanced enzymatic hydrolysis

Comparative study of alkaline, acidic, and deep eutectic solvent pretreatments on lignocellulosic biomass for enhanced enzymatic hydrolysis

Development of Alginate Hydrogels Incorporating Essential Oils Loaded in Chitosan Nanoparticles for Biomedical Applications.

A hybrid alginate hydrogel-chitosan nanoparticle system suitable for biomedical applications was prepared. Chitosan (CS) was used as a matrix for the encapsulation of lavender (Lavandula angustifolia) essential oil (LEO) and Mentha (Mentha arvensis) essential oil (MEO). An aqueous solution of an acidic Natural Deep Eutectic Solvent (NADES), namely choline chloride/ascorbic acid in a 2:1 molar ratio, was used to achieve the acidic environment for the dissolution of chitosan and also played the role of the ionic gelator for the preparation of the chitosan nanoparticles (CS-NPs). The hydrodynamic diameter of the CS-MEO NPs was 130.7 nm, and the size of the CS-LEO NPs was 143.4 nm (as determined using Nanoparticle Tracking Analysis). The CS-NPs were incorporated into alginate hydrogels crosslinked with CaCl2. The hydrogels showed significant water retention capacity (>80%) even after the swollen sample was kept in the aqueous HCl solution (pH 1.2) for 4 h, indicating a good stability of the network. The hydrogels were tested (a) for their ability to absorb dietary lipids and (b) for their antimicrobial activity against Gram-positive and Gram-negative foodborne pathogens. The antimicrobial activity of the hybrid hydrogels was comparable to that of the widely used food preservative sodium benzoate 5% w/v.

Development of Functional Biointerface Using Mixed Zwitterionic Silatranes.

Strategies to design multifunctional interfaces for biosensors have been extensively investigated to acquire optimal sensitivity, specificity, and accuracy. However, heterogeneous ingredients in clinical samples inevitably generate background signals, exposing challenges in biosensor performance. Polymer coating has been recognized as a crucial method to functionalize biointerfaces by providing tailored properties that are essential for interacting with biological systems. Herein, we introduce for the first time two oligomeric silatranes, MPS-MPCn and MPS-PEGMACOOHm, which were copolymerized from mercaptopropylsilatrane (MPS) with either zwitterionic monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) or carboxylated poly(ethylene glycol) methacrylate (PEGMACOOH) through thiol-ene polymerization. These oligomeric silatranes were prepared individually and in combinations in acidic and nonacid solvents for deposition on silicon wafers. Afterward, coating properties, including wettability, thickness, and elemental composition, were characterized by contact angle meter, ellipsometer, and X-ray photoelectron spectroscopy (XPS), respectively. Importantly, MPS-MPCn polymers were found to form thin films with high hydrophilicity and superior fouling repulsion to bacteria and protein, while mixed coating involving 70% MPS-PEGMACOOH2.5 and 30% MPS-MPC2.5 exhibited thinnest coating with best wettability among COOH-terminated coatings. Furthermore, the functional COOH group in the coated surfaces was exploited for postmodification with biological molecules via intermediated N-hydroxysuccinimide (NHS) ester group by amine coupling chemistry. Once again, the combination of 70% MPS-PEGMACOOH2.5 and 30% MPS-MPC2.5 provided an ultimate reduction in nonspecific adsorption (NSA) and established a finest signal discrimination through enzyme-linked immunosorbent assay. Consequently, these novel mixed oligomeric silatranes offer a promising approach for the construction of biosensor interfaces with dual functions in both nonspecific binding prevention and conjugation of biomolecules.

Electrospun gelatin/hyaluronic acid nanofibers as a platform for uric acid delivery to neural tissue.

Uric acid (UA) is an antioxidant that has been reported to be a neuroprotective compound for injuries and diseases, and specifically, diseases of the central nervous system. However, uric acid is highly insoluble in aqueous solutions, and high levels in the serum lead to gout, which limits its use in humans. Here, we develop a novel drug delivery platform that will release uric acid in a sustained manner for application to neural tissue. We demonstrate that one-step incorporation of UA into an electrospun gelatin/hyaluronic acid nanofiber mat results in controlled release of UA in culture medium. Taking a unique approach, we made solutions of 12% gelatin and 1% hyaluronic acid in a formic acid solvent and added UA for production of nanofiber mats. We then dehydrothermally crosslinked the mats and tested for release of UA into physiological cell culture medium. To test whether the mats have any detrimental effects on healthy nervous system tissue, we cultured spinal cord explants on the mats extended and assessed extensions from the explants. We observed that comparable numbers and lengths of dendrites are extended from the spinal cord tissue, regardless of the amount UA content in the mats. Our results suggest that electrospun gelatin/hyaluronic acid nanofibers can be used as a platform for sustained uric acid delivery to neural tissue without detrimental effects.

Retinol-loaded deep eutectic solvent emulsion: Improved stability and therapeutic efficiency

Retinol is used to manage epidermal and keratin metabolism, promote collagen formation, erase wrinkles for firmer skin, and restore suppleness and smoothness. Retinol can be difficult to store and use owing to the potential for skin irritation, oxidation, and biological ineffectiveness. The linolenic acid and phosphatidylcholine deep eutectic solvent (DES) had a low melting point, high bioactivity, and integrated capsule technology for retinol encapsulation. Safety evaluation tests revealed that the formulated DES-retinol emulsion was less cytotoxic than free retinol, as well as less irritant toward chicken embryos, pig skin, and human patches. In a keratinocyte inflammatory factor inhibition assay, the DES-retinol emulsion reduced monocyte chemoattractant protein-1 expression, indicating the potential to reduce the inflammatory response of the skin to retinol-induced irritation. The DES-retinol emulsion exhibited pro-permeability, anti-wrinkle, firming, and antioxidant characteristics in cellular, skin, and clinical investigations. The DES-retinol emulsion promoted type I collagen production, suppressed matrix metalloproteinase-1 activity, and reduced the release of reactive oxygen species. Consequently, the quantity, size, and depth of wrinkles were substantially improved, along with an enhanced anti-aging effect, heightened skin hydration, increased collagen intensity and flexibility, and diminished retinol-induced irritation. In conclusion, the retinol-loaded linolenic acid and phosphatidylcholine DES emulsion exhibited improved stability, enhanced transdermal efficiency, and notable therapeutic effects.

Uncovering structure-activity relationships in Brønsted acidic deep eutectic solvents for extractive and oxidative desulfurization

Modeling the structure-activity relationships (SARs) of deep eutectic solvents (DESs) is crucial for upgrading their catalytic performance in targeted reactions. Herein, a series of Brønsted acidic DESs are developed for the SARs research at molecular and atomic levels. Experimental and theoretical results suggest that the catalytic activity increases with the decreasing distances between O atom of active sites in DESs and S atom in sulfur compounds, and the R2 between EODS efficiency and the valid distances of O···S is above 0.9. Such geometric configuration can be optimized by altering the composition of DESs, which in turn substantially triggers the reaction acceleration between active intermediates and substrates. The resulting DES (TEAC/2BSA) achieved deep desulfurization for various sulfur compounds based on the optimal valid distances of O···S. This work contributes to a deep understanding of the reaction mechanism and enables the effective screening of task-specific DESs.

Light Harvesting Materials: A Study on Förster Resonance Energy Transfer and Optoelectronic Properties of Potential Nerium oleander Flowers.

The present study focused on extracting the anthocyanin dyes in ethanol, acidic ethanol, methanol, and acidic methanol solvents from Nerium oleander flowers by a simple maceration extraction process. FTIR spectroscopy and vibrational studies have confirmed the existence of polyphenolic groups in 2-phenyl chromenylium (anthocyanin) dyes. The optoelectronic results show the least direct bandgap (2.89 eV), indirect bandgap (1.98 eV), Urbach energy (0.120 eV), high refractive index (1.654), dielectric constant (3.294) and high optical conductivity (1.813 103 S/m) for the anthocyanin dye extracted found in acidic ethanol solvent. The photoluminescence properties such as Stokes' shift, quantum yield, and lifetime results show that anthocyanin dyes are promising candidates for red-LEDs and optical materials. The excellent correspondence between the absorption and emission spectra reinforces that the anthocyanins are efficient (89%) FRET probes. Further, the donor and acceptor undergo redshift in excitation and emission spectra in all studied solvents. The photometric properties such as CIE, CRI, CCT and color purity results of anthocyanins in all studied solvents revealed that this material exhibits pink to red shades (x = 0.40 → 0.50 and y = 0.46 → 0.39) and is well suitable for have great potential in the manufacturing of Organic-LEDs and other optoelectronic device applications.

Promoted lignocellulose fractionation and improved enzymatic hydrolysis of corn stalks through cationic surfactant combined with deep eutectic solvent pretreatment

The efficient conversion of lignocellulose relies on the implementation of an effective pretreatment strategy. Cationic surfactants combined with deep eutectic solvent ([Betaine][LA] was employed as a novel pretreatment strategy for treating corn stalks. Valuable insights were provided on the impact of the surfactant hydrophobic segment length on pretreatment efficacy. The specific pretreatment conditions were optimized by single factor and orthogonal experiment. Octadecyl trimethyl ammonium bromide (OTAB, 1.5 wt%) with the longest hydrophobic part combined with [Betaine][LA] (Betaine-to-LA molar ratio 1:4) achieved the best pretreatment effect (delignification 92.8 %, xylan elimination 91.1 %) when severity factor reached 4.26, meanwhile, 1.7 g/L xylo-oligosaccharides and 4.4 g/L furfural were detected in pretreatment liquid due to the hydrolysis of hemicellulose in corn stalks with acidic deep eutectic solvent [Betaine][LA]. The relative saccharification activity reached 2.7 times of raw material, while the lignin surface area significantly decreased, leading to enhanced cellulose accessibility. Additionally, molecular perspective provided by molecular dynamics showed the elimination of lignin and xylan was facilitated by strong interaction of hydrogen-bond and van der Waals force between lignin and hemicellulose with [Betaine][LA] + OTAB. Overall, the effectiveness and potential of cationic surfactant combined deep eutectic solvent pretreatment strategy for lignocellulose pretreatment was revealed.

Optimization of the demineralization process of black soldier fly (Hemertia illucens) pupa shell maggot chitosan and the physicochemical characteristics

Chitosan is a derivative compound of chitin that has undergone deacetylation. Chitosan has three stages of the manufacturing process, including demineralization, deproteinization, and deacetylation. Chitin is also found in the black soldier fly maggot pupae, but maggot pupae contain high minerals content that can affect the purity of the resulting chitosan. Therefore, demineralization treatment is necessary to remove minerals from maggot pupae shells. This study aims to optimize the demineralization process by finding the best type of acid solvent, the best incubation time, and combination treatments. The black soldier fly (BSF) maggot pupa shell was soaked using various formic acid, hydrochloric acid, and nitric acid solutions with incubation times of 60, 120, and 180 minutes. Chitosan characterization was carried out following SNI 7949:2022, including water content, ash content, nitrogen content, pH, deacetylation degree, characterization of functional groups with FT-IR, and as an antimicrobial comparison is formalin. The best demineralization treatment was obtained at 0.5 M nitric acid treatment with an incubation time of 120 minutes. The characterization of chitosan produced 7.81% water content, 0.56% ash content, 4.73% nitrogen content, pH 7.39, and 75.14% deacetylation degree. Characterization of groups on chitosan with FT-IR resulted in the absorption of O-H and N-H groups 3484 cm-1 and 3152 cm-1; C-H 2877 cm-1; and C=O 1653 cm-1. The inhibitory power against E. coli of the BSF maggot pupa shells chitosan is better compared to chitosan standard but not better than formalin.