Water Solubility Characteristics Research Articles

Synthetic Protocols, Structural Activity Relationship, and Biological Activity of Piperazine and its Derivatives.

The versatile basic structure of piperazine allows for the development and production of newer bioactive molecules that can be used to treat a wide range of diseases. Piperazine derivatives are unique and can easily be modified for the desired pharmacological activity. The two opposing nitrogen atoms in a six-membered piperazine ring offer a large polar surface area, relative structural rigidity, and more acceptors and donors of hydrogen bonds. These properties frequently result in greater water solubility, oral bioavailability, and ADME characteristics, as well as improved target affinity and specificity. Various synthetic protocols have been reported for piperazine and its derivatives. In this review, we focused on recently published synthetic protocols for the synthesis of the piperazine and its derivatives. The structure-activity relationship concerning different biological activities of various piperazine-containing drugs was also highlighted to provide a good understanding to researchers for future research on piperazines.

Characterizing water solubility of fresh and aged secondary organic aerosol in PM2.5 with the stable carbon isotope technique

Abstract. The investigation of the water-soluble characteristics of secondary organic carbon (SOC) is essential for a more comprehensive understanding of its climate effects. However, due to the limitations of the existing source apportionment methods, the water solubility of different types of SOC remains uncertain. This study analyzed stable carbon isotope and mass spectral signatures of total carbon (TC) and water-soluble organic carbon (WSOC) in ambient PM2.5 samples for 1 year and established stable carbon isotope profiles of fresh and aged SOC. Furthermore, a Bayesian stable isotope mixing (BSIM) model was employed to reveal the water solubility characteristics of fresh and aged SOC in a coastal megacity of China. WSOC was dominated by secondary sources, with fresh and aged SOC contributing 28.1 % and 45.2 %, respectively. Water-insoluble organic carbon (WIOC) was dominated by primary sources, to which fresh and aged SOC contributed 23.2 % and 13.4 %. We also found that the aging degree of SOC has considerable impacts on its water solubility due to the much higher water-soluble fraction of aged SOC (76.5 %) compared to fresh SOC (54.2 %). Findings of this study may provide a new perspective for further investigation of the hygroscopicity effects of SOC with different aging degrees on light extinction and climate change.

Preparation, Characterization and Drug Delivery Research of γ-Polyglutamic Acid Nanoparticles: A Review.

γ-Polyglutamic acid is a kind of biomaterial and environmentally friendly polymer material with the characteristics of water solubility and good biocompatibility. It has a wide range of applications in medicine, food, cosmetics and other fields. This article reviews the preparation, characterization and medical applications of γ-polyglutamic acid nanoparticles. Nanoparticles prepared by using γ- polyglutamic acid not only had the traditional advantages of enhancing drug stability and slow-release effect, but also were simple to prepare without any biological toxicity. The current methods of nanoparticle preparation mainly include the ion gel method and solvent exchange method, which use the total electrostatic force, van der Waals force, hydrophobic interaction force and hydrogen bond force between molecules to embed materials with different characteristics. At present, there are more and more studies on the use of γ-polyglutamic acid to encapsulate drugs, and the research on the mechanism of its encapsulation and sustained release has gradually matured. The development and application of polyglutamic acid nanoparticles have broad prospects.

Hemay181: A novel SDC (sugar linked drug conjugate) for solid tumors targeting tumor microenvironment.

e15006 Background: Hemay181 is a novel broad-spectrum conjugated cytotoxic drug for treating advanced solid tumours. The drug exerts its inhibitory effect on tumour growth by releasing cytotoxic drug SN-38 in tumour tissues via β-glucuronidase (βGU) metabolism to inhibit the activity of topoisomerase I (TOP1). The water solubility of Hemay181 is increased > 5000-fold compared to SN-38. Hemay181 also binds to plasma albumin to form a macromolecular drug transporter, significantly improving the drug's pharmacokinetics. In addition, βGU has low activity in normal tissues, localised to the lysosomes, but is highly expressed in the hypoxic tumour microenvironment. Methods: In vitro and In Vivo studies showed Hemay181 inhibited growth in 29 human tumour cell lines and 16 human tumor Xenograft models, including colorectal cancer, gastric cancer, triple-negative breast cancer, head and neck cancer, pancreatic cancer, lung cancer, prostate cancer and melanoma. Results: In the absence of βGU, Hemay181 showed significantly weaker inhibitory activity than Hemay181+βGU or no significant inhibitory activity. In these In vitro studies with the addition of βGU, the activity was similar to SN-38, ranging from 3.9 nM to 159 nM. Hemay181 showed tumor selectivity with low activity against two normal human cell lines. The IC50 values of Hemay181 against Chang liver (normal liver cells) and MRC 5 (embryonic lung cells) were 318 nM and 14566 nM under non-enzymatic digestion conditions. In vivo, Hemay181 had significant inhibitory effects on the growth of human colorectal cancer, pancreatic cancer, head and neck cancer, triple-negative breast cancer, lung cancer, liver cancer, ovarian cancer and gastric cancer tumour models. The lowest effective dose of Hemay181 was 1.875mg/kg in the human colon cancer HCT116 model. Within the dose range of 3.75~60 mg/kg, the highest inhibitory rate of the above different tumour models could reach more than 90%. Hemay181 significantly reduced tumour volume compared to irinotecan, which only slowed the tumour growth rates. There was no significant decrease in the body weight of Hemay181 in these studies. In the colon cancer PDX model (CR0029) (30mg/kg), the tumour inhibition rate (TGI) was 78%. At 60mg/kg, in triple-negative breast cancer (BR1458) and non-small cell lung cancer (LU3075) PDX models, a TGI was 97% and 98%, respectively. At 60mg/kg, there was a significant tumour suppressive effect on larger tumours treated with irinotecan, with a reduction of tumour volume. In vitro , 1 μM Hemay181 is stable in CD1 mouse and SD rat plasma, with a minor degree of metabolism in beagle dog, cynomolgus monkey and human plasma. Conclusions: In summary, the novel broad-spectrum anti-tumour drug Hemay181 has the characteristics of high water solubility, tumour-targeting ability, low toxicity and side effects on normal tissues. It is under evaluation in ongoing clinical studies.

Impact of Cerium Oxide Nanoparticles Incorporation on Water Sorption and Solubility of Acrylic-Based Denture Soft Lining Material

Denture soft liners are specifically engineered to enhance patient performance by altering the surfaces of prosthetics that come into touch with the soft tissues within the oral cavity. Acrylic resin Polymethyl methacrylate (PMMA) based and silicone elastomer-based are the two main types of denture soft liners. Nanotechnology was employed as a means to enhance the mechanical qualities of dentures. The primary objective of this investigation was to examine the impact of cerium oxide (CeO2) nanoparticles (NPs) on the water sorption and solubility characteristics of acrylic-based soft liners. The data was subjected to analysis of variance (ANOVA). The surface characteristics were determined using scanning electron microscopy (SEM). This in vitro study demonstrates that including CeO2 NPs at 2% and 3% concentrations does not impact acrylic-based soft lining materials' water sorption and solubility. The solubility of CeO2 is well-recognized to be very low. The results indicated that there were no statistically significant differences between the groups.

The medicinal chemistry of piperazines: A review.

The versatile basic structure of piperazine allows for the development and production of newer bioactive molecules that can be used to treat a wide range of diseases. Piperazine derivatives are unique and can easily be modified for the desired pharmacological activity. The two opposing nitrogen atoms in a six-membered piperazine ring offer a large polar surface area, relative structural rigidity, and more acceptors and donors of hydrogen bonds. These properties frequently result in greater water solubility, oral bioavailability, and ADME characteristics, as well as improved target affinity and specificity. Various synthetic protocols have been reported for piperazine and its derivatives. In this review, we focused on recently published synthetic protocols for the synthesis of the piperazine and its derivatives. The structure-activity relationship concerning different biological activities of various piperazine-containing drugs has also been highlighted to provide a good understanding to researchers for future research on piperazines.

Polyglutamate: Unleashing the Versatility of a Biopolymer for Cosmetic Industry Applications

Polyglutamic acid (PGA), a biopolymer comprising repeating units of glutamic acid, has garnered significant attention owing to its versatile applications. In recent years, microbial production processes have emerged as promising methods for the large-scale synthesis of PGA, offering advantages such as sustainability, efficiency, and tailored molecular properties. Beyond its industrial applications, PGA exhibits unique properties that render it an attractive candidate for use in the cosmetic industry. The biocompatibility, water solubility, and film-forming characteristics of PGA make it an ideal ingredient for cosmetic formulations. This article explores the extensive potential cosmetic applications of PGA, highlighting its multifaceted role in skincare, haircare, and various beauty products. From moisturizing formulations to depigmentating agents and sunscreen products, PGA offers a wide array of benefits. Its ability to deeply hydrate the skin and hair makes it an ideal ingredient for moisturizers, conditioners, and hydrating masks. Moreover, PGA’s depigmentating properties contribute to the reduction in hyperpigmentation and uneven skin tone, enhancing the overall complexion. As the demand for sustainable and bio-derived cosmetic ingredients escalates, comprehending the microbial production and cosmetic benefits of PGA becomes crucial for driving innovation in the cosmetic sector.

Formulation and organoleptic characteristics of flavor enhancer from shrimp head protein hydrolysate

Protein hydrolysate can be produced from by-products of the fishing industry, such as shrimp heads. This product is made by enzyme hydrolysis through the breakdown of shrimp head protein into short-chain peptides and amino acids. Enzymatic hydrolysis produces protein hydrolysate, which has savory, umami, and water-soluble characteristics. The savory and umami taste results from the high content of glutamic acid and other free amino acids. This study aimed to determine the best formulation and organoleptic characteristics of the shrimp head protein hydrolysate flavor enhancer. Production of shrimp head protein hydrolysate (SPH) using alkalase enzyme at a temperature of 55°C with an enzyme concentration of 20,000 units/kg substrate for 7 hrs. Parameters tested were yield, proximate and amino acid analysis, and organoleptic test for SPH flavor enhancer. SPH has an amino acid composition dominated by arginine, alanine, glycine, glutamic acid, leucine and lysine. The flavor enhancer with 40% SPH composition was chosen as the best formula because it has sensory characteristics close to P0 commercial flavoring. The dominant sensory attributes were spicy, salty, umami and sweet. Overall, protein hydrolysate-based flavor enhancers' solubility and color properties are close to commercial flavor enhancers. The flavor enhancer made from SPH has the potential to be used as a substitute for commercial flavor enhancers which are rich in essential amino acids.

Concepts and principles for new rapid simple liquid chromatography method for quantification of antioxidants resveratrol, vitamin E, and coenzyme Q10 in capsules with high-performance liquid chromatography with a photo-diode array detector.

Principles and problems in the development of simultaneous liquid chromatography (LC) analytical methods for potent antioxidative molecules resveratrol, tocopherol, and coenzyme Q10 in capsules, have been investigated and systematically compared and summarized. For these purposes, experiments within the full polarity spectrum of LC techniques. were tested and recorded. The whole range of polarities included: Alkyl C18 bonded reversed phase, phenyl, cyanopropyl, diol, and the most polar base silica-filled column matrixes have been used. The summarized results concluded that all mentioned LC techniques could be used for the determination of the mentioned group of the three analytes with different run characteristics and efficiency. These successes could be achieved after careful analyses of molecular physicochemical data of analytes. They are especially organic solubilities. The ultraviolet spectral absorption characteristics of each analyte and the mobile phase constituents for appropriate separation were very important to be known. The ultimate targets were the development method with the isocratic mode of separation yielding symmetrical peak shapes for the best sensitivity and accuracy, with the shortest run time and best reproducibility. From an analytical point of view important for LC, the three analytes have quite distinct characteristics that contribute to successful method development. These features are their organic solvent and water solubility, molecular polarities, and ultraviolet-absorption characteristics, like spectra and absorptivities. All these mentioned parameters were taken into account for solving complications appearing in the development of rapid LC methods for the simultaneous determination of three antioxidant molecules.

Design and preparation of multifunctional astaxanthin nanoparticles with good acid stability and hepatocyte-targeting ability for alcoholic liver injury alleviation

As a dietary nutrition supplement, astaxanthin (AXT) has attracted much attention in alleviating ethanol-induced liver injury due to its superior antioxidant ability. However, the poor water solubility and pH-vulnerable characteristics of AXT significantly restrict its application in nutrition intervention. In this study, multifunctional astaxanthin nanoparticles (LAD6:1@AXT) with good acid stability and hepatocyte-targeting ability were designed and prepared using 2-hydroxypropyl-β-cyclodextrin, lactobionic acid, and sodium alginate as raw materials. At pH 2.0, LAD6:1@AXT displayed a double reservation rate of the relative AXT content compared to free AXT. Significant antioxidative activity of LAD6:1@AXT was observed in cellular experiments. Ex vivo experiments revealed that the astaxanthin nanoparticles showed 90 % increased accumulation in the liver after oral administration for 24 h. A strong hepatic-targeting effect was found for LAD6:1@AXT, which could effectively ameliorate alcoholic liver injury. Our data indicated that the developed astaxanthin nanoparticles have the potential of nutrition intervention for alcohol-induced liver impairment.

Self-assembled gel-assisted preparation of high-performance hydrophobic PDMS@MWCNTs/PEDOT:PSS composite aerogels for wearable piezoresistive sensors

The conductive polymer poly(3,4-thylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) exhibits potential in the development of flexible devices due to its unique conjugated structure and water-solubility characteristics. To address the incompressibility of the original PEDOT:PSS aerogel without compromising its high conductivity, a stable interpenetrating polymer network (IPN) was self-assembled by guiding the molecular motion within PEDOT:PSS and introducing multi-walled carbon nanotubes (MWCNTs). By combining critical surface removal, directional freeze-drying, and polydimethylsiloxane (PDMS) reinforcement processes, a hydrophobic PDMS@MWCNTs/PP aerogel with a highly oriented porous structure and high strength was prepared. Under the synergistic effect of MWCNTs/PEDOT:PSS electroactive scaffold, the composite aerogel exhibited a high sensitivity of up to 16.603 kPa−1 at 0–2 kPa, a fast response time of 74 ms, and excellent repeatability. Moreover, the sensor possessed hydrophobicity with a good water contact angle of 137° The sensor could serve as a wearable electronic monitoring device to achieve accurate and sensitive detection of human motion including large-scale human activities and tiny muscle movements. Therefore, our findings provide a new direction to fabricate high-performance piezoresistive sensors based on three-dimensional (3D) conductive polymer active scaffolds, demonstrating their great potential for flexible electronics, human-computer interaction, and a wide range of applications under special working conditions.

Regulation Mechanism of Phenolic Hydroxyl Number on Self-Assembly and Interaction between Edible Dock Protein and Hydrophobic Flavonoids.

In this study, galangin (Gal), kaempferol (Kae), quercetin (Que), and myricetin (Myr) were chosen as the representative flavonoids with different phenolic hydroxyl numbers in the B-ring. The edible dock protein (EDP) was chosen as the new plant protein. Based on this, the regulation mechanism of the phenolic hydroxyl number on the self-assembly behavior and molecular interaction between EDP and flavonoid components were investigated. Results indicated that the loading capacity order of flavonoids within the EDP nanomicelles was Myr (10.92%) > Que (9.56%) > Kae (6.63%) > Gal (5.55%). Moreover, this order was consistent with the order of the hydroxyl number in the flavonoid's B ring: Myr (3) > Que (2) > Kae (1) > Gal (0). The micro morphology exhibited that four flavonoid-EDP nanomicelles had a core-shell structure. In the meantime, the EDP encapsulation remarkably improved the flavonoids' water solubility, storage stability, and sustained release characteristics. During the interaction of EDP and flavonoids, the noncovalent interactions including van der Waals forces, hydrophobic interaction, and hydrogen bonding were the main binding forces. All of the results demonstrated that the hydroxyl number of bioactive compounds is a critical factor for developing a delivery system with high loading ability and stability.

Influence of extruded whole wheat flour addition on quality characteristics of pasta

SummaryThis work aimed to develop the whole wheat (common) flour pasta by incorporation of whole wheat flour modified by extrusion process at various percentages and assess the effect of modified extruded whole wheat flour (EWWF) on quality characteristics of pasta. The whole wheat flour was modified by extruding it at 15% feed moisture, 148 °C extrusion temperature and 434 rpm screw speed through a twin screw extruder. The modified EWWF was added to the whole wheat flour at a 10%–40% substitution level with whole wheat flour for the preparation of pasta and its quality was compared against the semolina pasta and pasta prepared from whole wheat flour. The study characterized the functional, antioxidant properties, in vitro starch and protein digestibility, cooking parameters and colour properties of the EWWF pasta. Extrusion increased the water absorption, water solubility and oil absorption characteristics of EWWF. The total phenolic content (TPC) and total flavonoid content (TFC) of pasta (0%—40%) ranged from 170.07 to 146.04 mg GAE/100 g and 156.00 to 137.60 mg CE/100 g, respectively, compared to the semolina pasta. The antioxidant properties of the EWWF pasta decreased after the incorporation of extruded flour. The pasta prepared with the incorporation of 40% EWWF showed the best cooking properties. The colour of EWWF pasta turned darker compared to semolina pasta. The pasta prepared with the use of EWWF could be utilized as a healthy alternative to the existing pasta in India.

Temperature responsive crosslinked starch-kraft lignin macromolecule

Starch is a natural polymer with a relatively simple structure and limited solubility in water. Kraft lignin (KL) is a complex biopolymer obtained as a by-product from the delignification of wood and grasses. The present work reports developing a temperature-responsive high molecular weight macromolecule from crosslinking KL and starch (KLS). The NMR and XPS analyses quantified the changes in the aromatic and anhydroglucose units of KL and starch, observing a higher content of C-O-C bonds, which confirms the presence of glycerol ether cross-linkages between starch and KL in KLS. The rheological analysis of KLS dispersions revealed the formation of a thermo-responsive structured network. The temperature-dependent water solubility and rheological characteristics of KLS were related to the presence of hydrophilic starch chains, crosslinking degree, and physicochemical characteristics of KL. The incorporation of KL and ether crosslinks increased the thermal stability of KLS. Because of its multiple functional groups and large molecular weight (3.6–4.2 × 105 g/mol) that was arranged in an extended globular shape, KLS-5 formed a gel-like structure after a heating-cooling treatment. Overall, the results confirmed that incorporating lignin in starch would fabricate sustainable materials with potentially altered applications, such as temperature-responsive hydrogels and films.

Design of a selective and water-soluble fluorescent probe targeting Tau fibrils for intracellular and in vivo imaging

Tau protein has attracted much research interest in recent years. Development of effective techniques for in vivo imaging of Tau protein with high sensitivity and selectivity is of great importance. Herein, we rationally designed two novel, Tau-selective and AIE-active fluorescent probes (JL-3 and JL-6). Triphenylamine (TPA) as the AIE group, was first linked with a -CN group and N, N’-dimethylaminobenzene by π-π conjugation to form a D-A-D structure. Then, a hydrophilic unit was conjugated to increase probe hydrophilicity. The AIE-activity and water-solubility characteristics contributed to larger Stokes shift and quantum yields, decreased background fluorescence and therefore enhanced the signal-to-noise ratio of the detection. An excellent discrimination between Tau and β-amyloid (Aβ) aggregates (4.3- and 3.5- times higher Tau-over-Aβ) was obtained on JL-3 and JL-6. Taking JL-3 as the example, an excellent linear relationship between Tau concentrations from 50 nM to 5 μM and fluorescence was obtained (detection limit, 14.9 nM). Finally, JL-3 demonstrated a remarkable capacity for bioimaging in living cells, brain tissues and transgenic mice. Collectively, our results illustrated the potential of the developed probes as Tau-specific fluorescent dyes for both in vitro and in vivo applications.

Effects of food formulation on bioavailability of phytosterols: phytosterol structures, delivery carriers, and food matrices.

Daily intake of phytosterols (PSs) as a diet supplement can lower blood-cholesterol levels and reduce the risks of cardiovascular diseases. However, the high crystallinity, low water solubility, easy oxidizability, and other characteristics of PSs restrict their application and bioavailability in food products. The formulation parameters including the structures of PSs, delivery carriers, and food matrices may play an important role in the release, dissolution, transport, and absorption of PSs in functional foods. In this paper, the effects of formulation parameters, including phytosterol structures, delivery carriers, and food matrices, on the bioavailability of phytosterols are summarized and suggestions are provided for the formulation design of functional foods. The side chain and hydroxyl esterification group of PSs may significantly affect their lipid or water solubilities and micellization capacities, which in turn affect the bioavailability of PSs. Selecting suitable delivery carriers based on the characteristics of the food system can reduce the crystallinity and oxidation of PSs and control the release of PSs, thereby improving the PS stability and delivery efficiency. Moreover, the ingredients of the carriers or food products would also influence the release, solubility, transport, and absorption of PSs in the gastrointestinal tract (GIT).

Biomimetic Antidote Nanoparticles: a Novel Strategy for Chronic Heavy Metal Poisoning.

Chronic lead poisoning has become a major factor in global public health. Chelation therapy is usually used to manage lead poisoning. Dimercaptosuccinic acid (DMSA) is a widely used heavy metal chelation agent. However, DMSA has the characteristics of poor water solubility, low oral bioavailability, and short half-life, which limit its clinical application. Herein, a long-cycle slow-release nanodrug delivery system was constructed. We successfully coated the red blood cell membrane (RBCM) onto the surface of dimercaptosuccinic acid polylactic acid glycolic acid copolymer (PLGA) nanoparticles (RBCM-DMSA-NPs), which have a long cycle and detoxification capabilities. The NPs were characterized and observed by particle size meters and transmission electron microscopy. The results showed that the particle size of RBCM-DMSA-NPs was approximately 146.66 ± 2.41nm, and the zeta potential was - 15.34 ± 1.60mV. The homogeneous spherical shape and clear core-shell structure of the bionic nanoparticles were observed by transmission electron microscopy. In the animal tests, the area under the administration time curve of RBCM-DMSA-NPs was 156.52 ± 2.63 (mg/L·h), which was 5.21-fold and 2.36-fold that of free DMSA and DMSA-NPs, respectively. Furthermore, the median survival of the RBCM-DMSA-NP treatment group (47days) was 3.61-fold, 1.32-fold, and 1.16-fold for the lead poisoning group, free DMSA, and DMSA-NP groups, respectively. The RBCM-DMSA-NP treatment significantly extended the cycle time of the drug in the body and improved the survival rate of mice with chronic lead poisoning. Histological analyses showed that RBCM-DMSA-NPs did not cause significant systemic toxicity. These results indicated that RBCM-DMSA-NPs could be a potential candidate for long-term chronic lead exposure treatment.

Chitosan degradation products promote healing of burn wounds of rat skin.

Burns can impair the barrier function of the skin, and small burns can also cause high mortality. The WHO has described that over 180,000 people die of burns worldwide each year. Thus, the treatment of burn wounds is a major clinical challenge. Chitooligosaccharides (COS) are alkaline amino oligosaccharides with small molecular weights obtained by enzyme or chemical degradation of chitosan. With the characteristics of biocompatibility, water solubility and degradability, it has attracted increasing attention in the fields of biomedicine. In the present study, we used COS to treat deep second-degree burn wounds of rat skin and found that COS was able to promote wound healing. We also revealed that COS could promote fibroblast proliferation. Transcriptome sequencing analysis was performed on COS-treated fibroblasts to identify the underlying mechanisms. The results showed that COS was able to promote wound healing through regulation of the mitogen-activated protein kinase (MAPK) pathway and growth factor Hepatocyte Growth Factor (HGF). Our results provide a potential drug for burn wound therapy and the related molecular mechanism.

In-situ forming hydrogel based on thiolated chitosan/carboxymethyl cellulose (CMC) containing borate bioactive glass for wound healing

Suitable wound dressings for accelerating wound healing are actively being designed and synthesised. In this study, thiolated chitosan (tCh)/oxidized carboxymethyl cellulose (OCMC) hydrogel containing Cu-doped borate bioglass (BG) was developed as a wound dressing to improve wound healing in a full-thickness skin defect of mouse animal model. Thiolation was used to incorporate thiol groups into chitosan (Ch) to enhance its water solubility and mucoadhesion characteristics. Here, the in situ forming hydrogel was successfully developed using the Schiff-based reaction, and its physio-chemical and antibacterial characteristics were examined. Borate BG was also incorporated in the generated hydrogel to promote angiogenesis and tissue regeneration at the wound site. Investigations of in vitro cytotoxicity assays demonstrated that the synthesised hydrogels showed good biocompatibility and promoted cell growth. These results inspired us to investigate the effectiveness of skin wound healing in a mouse model. On the backs of animals, two full-thickness wounds were created and treated utilising two different treatment conditions: (1) OCMC/tCh hydrogel, (2) OCMC/tCh/borate BG, and (3) control defect. The wound closure ratio, collagen deposition, and angiogenesis activity were measured after 14 days to determine the healing efficacy of the in situ hydrogels used as wound dressings. Overall, the hydrogel containing borate BG was maintained in the defect site, healing efficiency was replicable, and wound healing was apparent. In conclusion, we found consistent angiogenesis, remodelling, and accelerated wound healing, which we propose may have beneficial effects on the repair of skin defects.

Epoxy Compositions with Reduced Flammability Based on DER-354 Resin and a Curing Agent Containing Aminophosphazenes Synthesized in Bulk Isophoronediamine.

A method for the synthesis of an amine-containing epoxy resin curing agent by dissolving hexakis-[(4-formyl)phenoxy]cyclotriphosphazene in an excess of isophoronediamine was developed. The curing agent was characterized via NMR and IR spectroscopy and MALDI-TOF mass spectrometry, and its rheological characteristics were studied. Compositions based on DER-354 epoxy resin and the synthesized curing agent with different amounts of phosphazene content were obtained. The rheological characteristics of these compositions were studied, followed by their curing. An improvement in several thermal (DSC), mechanical (compression, tension, and adhesion), and physicochemical (water absorption and water solubility) characteristics, as well as the fire resistance of the obtained materials modified with phosphazene, was observed, compared with unmodified samples. In particular, there was an improvement in adhesive characteristics and fire resistance. Thus, compositions based on a curing agent containing a 30% modifier were shown to fulfill the V-1 fire resistance category. The developed compositions can be processed by contact molding, winding, and resin transfer molding (RTM), and the resulting material is suitable for use in aircraft, automotive products, design applications, and home repairs.