Novel ultra-stretchable and self-healing crosslinked poly (ethylene oxide)-cationic guar gum hydrogel.

Hydrogels are three-dimensional structures with specific features that render them useful for biomedical applications, such as tissue engineering scaffolds, drug delivery systems, and wound dressings. In recent years, there has been a significant increase in the search for improved mechanical properties of hydrogels derived from natural products to extend their applications in various fields, and there are different methods to obtain strengthened hydrogels. Cationic guar gum has physicochemical properties that allow it to interact with other polymers and generate hydrogels. This study aimed to develop an ultra-stretchable and self-healing hydrogel, evaluating the influence of adding PolyOX [poly(ethylene oxide)] on the mechanical properties and the interaction with cationic guar gum for potential tissue engineering applications. We found that variations in PolyOX concentrations and pH changes influenced the mechanical properties of cationic guar gum hydrogels. After optimization experiments, we obtained a novel hydrogel, which was semi-crystalline, highly stretchable, and with an extensibility area of approximately 400 cm2, representing a 33-fold increase compared to the hydrogel before being extended. Moreover, the hydrogel presented a recovery of 96.8% after the self-healing process and a viscosity of 153,347 ± 4,662 cP. Therefore, this novel hydrogel exhibited optimal mechanical and chemical properties and could be suitable for a broad range of applications in different fields, such as tissue engineering, drug delivery, or food storage.

3,3'-Diindolylmethane and indole-3-carbinol: potential therapeutic molecules for cancer chemoprevention and treatment via regulating cellular signaling pathways.

Dietary compounds in cancer prevention have gained significant consideration as a viable method. Indole-3-carbinol (I3C) and 3,3'-diindolylmethane (DIM) are heterocyclic and bioactive chemicals found in cruciferous vegetables like broccoli, cauliflower, cabbage, and brussels sprouts. They are synthesized after glycolysis from the glucosinolate structure. Clinical and preclinical trials have evaluated the pharmacokinetic/pharmacodynamic, effectiveness, antioxidant, cancer-preventing (cervical dysplasia, prostate cancer, breast cancer), and anti-tumor activities of I3C and DIM involved with polyphenolic derivatives created in the digestion showing promising results. However, the exact mechanism by which they exert anti-cancer and apoptosis-inducing properties has yet to be entirely understood. Via this study, we update the existing knowledge of the state of anti-cancer investigation concerning I3C and DIM chemicals. We have also summarized; (i) the recent advancements in the use of I3C/DIM as therapeutic molecules since they represent potentially appealing anti-cancer agents, (ii) the available literature on the I3C and DIM characterization, and the challenges related to pharmacologic properties such as low solubility, and poor bioavailability, (iii) the synthesis and semi-synthetic derivatives, (iv) the mechanism of anti-tumor action in vitro/in vivo, (v) the action in cellular signaling pathways related to the regulation of apoptosis and anoikis as well as the cell cycle progression and cell proliferation such as peroxisome proliferator-activated receptor and PPARγ agonists; SR13668, Akt inhibitor, cyclins regulation, ER-dependent-independent pathways, and their current medical applications, to recognize research opportunities to potentially use these compounds instead chemotherapeutic synthetic drugs.

Films for Wound Healing Fabricated Using a Solvent Casting Technique.

Wound healing is a complex process that involves restoring the structure of damaged tissues through four phases: hemostasis, inflammation, proliferation, and remodeling. Wound dressings are the most common treatment used to cover wounds, reduce infection risk and the loss of physiological fluids, and enhance wound healing. Despite there being several types of wound dressings based on different materials and fabricated through various techniques, polymeric films have been widely employed due to their biocompatibility and low immunogenicity. Furthermore, they are non-invasive, easy to apply, allow gas exchange, and can be transparent. Among different methods for designing polymeric films, solvent casting represents a reliable, preferable, and highly used technique due to its easygoing and relatively low-cost procedure compared to sophisticated methods such as spin coating, microfluidic spinning, or 3D printing. Therefore, this review focuses on the polymeric dressings obtained using this technique, emphasizing the critical manufacturing factors related to pharmaceuticals, specifically discussing the formulation variables necessary to create wound dressings that demonstrate effective performance.

Cross-linked polyvinyl alcohol-xanthan gum hydrogel fabricated by freeze/thaw technique for potential application in soft tissue engineering.

The search for materials and process parameters capable of generating hydrogels for soft tissue engineering applications, based on an experimental design strategy that allows the evaluation of several factors involved in their development and performance, has greatly increased. Nevertheless, the fabrication technique can influence their mechanical properties, swelling, crystallinity, and even their susceptibility to contamination by microorganisms, compromising their performance within the tissue or organ. This study aimed to evaluate the influence of the freeze/thaw technique on different characteristics of polyvinyl alcohol-xanthan gum hydrogel. Methods: this research analyzed the critical variables of the freeze/thaw process through a systematic study of a 2 k factorial design of experiments, such as the proportion and concentration of polymers, freezing time and temperature, and freeze/thaw cycles. Additionally, physicochemical analysis, susceptibility to bacterial growth, and cell viability tests were included to approximate its cytotoxicity. The optimized hydrogel consisted of polyvinyl alcohol and xanthan gum at a 95 : 5 ratio, polymer mixture concentration of 15%, and 12 h of freezing with three cycles of freeze/thaw. The hydrogel was crystalline, flexible, and resistant, with tensile strengths ranging from 9 to 87 kPa. The hydrogel was appropriate for developing scaffolds for soft tissue engineering such as the cardiac and skeletal muscle, dermis, thyroid, bladder, and spleen. Also, the hydrogel did not expose an in vitro cytotoxic effect, rendering it a candidate for biomedical applications.

Stability Phenomena Associated with the Development of Polymer-Based Nanopesticides.

Pesticides have been used in agricultural activity for decades because they represent the first defense against pathogens, harmful insects, and parasitic weeds. Conventional pesticides are commonly employed at high dosages to prevent their loss and degradation, guaranteeing effectiveness; however, this results in a large waste of resources and significant environmental pollution. In this regard, the search for biocompatible, biodegradable, and responsive materials has received greater attention in the last years to achieve the obtention of an efficient and green pesticide formulation. Nanotechnology is a useful tool to design and develop "nanopesticides" that limit pest degradation and ensure a controlled release using a lower concentration than the conventional methods. Besides different types of nanoparticles, polymeric nanocarriers represent the most promising group of nanomaterials to improve the agrochemicals' sustainability due to polymers' intrinsic properties. Polymeric nanoparticles are biocompatible, biodegradable, and suitable for chemical surface modification, making them attractive for pesticide delivery. This review summarizes the current use of synthetic and natural polymer-based nanopesticides, discussing their characteristics and their most common design shapes. Furthermore, we approached the instability phenomena in polymer-based nanopesticides and strategies to avoid it. Finally, we discussed the environmental risks and future challenges of polymeric nanopesticides to present a comprehensive analysis of this type of nanosystem.

Platelet lysate-loaded PLGA nanoparticles in a thermo-responsive hydrogel intended for the treatment of wounds.

A thermo-responsive hydrogel of Pluronic F-127, containing PLGA nanoparticles loaded with a platelet lysate for wound treatment, was prepared. A high rate of incorporation of the lysate (about 80%) in the nanoparticles was achieved by the double emulsion-solvent evaporation method. The nanoparticles were characterized by measuring their size (about 318 nm), polydispersity index (0.29) and Z potential (-17.6), as well as by infrared and calorimetric techniques, and determining their stability as a function of time. It was found through measures of transepidermal water loss that the hydrogel containing the nanoparticles was capable of providing a semi-occlusive environment, necessary for the recovery of a wound. The inclusion of lysate in nanoparticles and this in turn in the hydrogel allowed a gradual release, which would avoid contact of the total dose with the biological medium. Studies with fibroblasts and in vivo in mice showed that the hydrogel containing nanoparticles with platelet lysate promoted faster tissue regeneration than the lysate in its free form, so this system is presented as a good alternative for the treatment of wounds.

Alkylglycerol Derivatives, a New Class of Skin Penetration Modulators.

The absorption modulating activity of two alkylglycerol derivatives (batyl and chimyl alcohol) on skin barrier properties was evaluated. Biophysical tests such as transepidermal water loss (TEWL) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, as well as in vitro skin permeation studies, were performed in order to determine the effect of these compounds as chemical absorption modulators. Four drugs were used as models: three NSAIDS (diclofenac, naproxen, and piroxicam) and glycyrrhizic acid. The results showed that treatment of the skin with alkylglycerols caused (i) a reduction on the amount of drug permeated; (ii) a reduction in TEWL; and (iii) changes in the ATR-FTIR peaks of stratum corneum lipids, indicative of a more ordered structure. All of these findings confirm that alkyl glycerols have an absorption retarding effect on the drugs tested. Such effects are expected to give rise to important applications in the pharmaceutical and cosmetic sectors, in cases where it is desirable for the drug to remain in the superficial layers of the skin to achieve a local effect.