Sergio A. Bernal-Chávez’s research while affiliated with Universidad de las Américas Puebla and other places

In this work, κ-carrageenan (κ-C) and polyethylene oxide (PEO) were utilized to synthesize polymeric films (κ-C-PEO). A 2 k experimental design was employed to optimize the synthesis of κ-C-PEO systems by considering the content of κ-carrageenan, PEO, and glycerin and their influence on the mechanical features of the resultant films. The κ-C-PEO systems were robustly characterized by FTIR spectroscopy, thermogravimetric analyses, and scanning electron microscopy (SEM). Magnesium oxide nanoparticles (MgO-NPs) were utilized to load κ-C-PEO films as an efficient approach to enhance their biological performance. The activity of κ-C-PEO films was studied against Gram-negative bacteria through the Kirby-Bauer assay. Artemia salina nauplii were cultured to assess the possible toxicity of κ-C-PEO films. The results demonstrated that κ-C-PEO films were elongated with the heterogeneous distribution of MgO-NPs. The tensile strength, thickness, and swelling capacity of κ-C-PEO films were 129 kPa, 0.19 mm, and 52.01%, respectively. TGA and DTA analyses revealed that κ-C-PEO films are thermally stable structures presenting significant mass loss patterns at >200 • C. Treatment with κ-C-PEO films did not inhibit the growth of Escherichia coli nor Pseudomonas aeruginosa. Against A. salina nauplii, κ-C-PEO films did not decrease the survival rate nor compromise the morphology of the tested in vivo model. The retrieved data from this study expand the knowledge about integrating inorganic nanomaterials with polysaccharide-based structures and their possible application in treating chronic wounds. Even though this work provides innovative insights into the optimal design of bioactive structures, further approaches are required to improve the biological performance of the synthesized κ-C-PEO films.

Background: In tissue engineering, developing injectable hydrogels with tailored mechanical and bioactive properties remains a challenge. This study introduces an injectable hydrogel composite for soft tissue regeneration, composed of oxidized alginate (OA) and N-succinyl chitosan (NSC) cross-linked via Schiff base reaction, reinforced with graphene oxide (GOx) and cyclic arginylglycylaspartic acid (c-RGD). The objective was to create a multifunctional platform combining injectability, bioactivity, and structural stability. Methods: The OA/NSC/GOx-cRGD hydrogel was synthesized through Schiff base cross-linking (aldehyde-amine reaction). Characterization included FTIR (C=N bond at 1650 cm⁻¹), Raman spectroscopy (D/G bands at 1338/1567 cm⁻¹), SEM (porous microstructure), and rheological analysis (shear-thinning behavior). In vitro assays assessed fibroblast viability (MTT) and macrophage TNF-α secretion (ELISA), while ex-vivo injectability and retention were evaluated using chicken cardiac tissue. Results: The hydrogel exhibited shear-thinning behavior (viscosity: 10 to <1 Pa·s) and elastic-dominated mechanics (G′ > G″), ensuring injectability. SEM revealed an interconnected porous structure mimicking native extracellular matrix. Fibroblast viability remained ≥95%, and TNF-α secretion in macrophages decreased by 80% (30 vs. 150 pg/μL in controls), demonstrating biocompatibility and anti-inflammatory effects. The hydrogel adhered stably to cardiac tissue without leakage. Conclusions: The OA/NSC/GOx-cRGD composite integrates injectability, bioactivity, and structural stability, offering a promising scaffold for tissue regeneration. Its modular design allows further functionalization with peptides or growth factors. Future work will focus on translational applications, including scalability and optimization for dynamic biological environments.

This study aimed to develop HGs based on cationic guar gum (CGG), polyethylene glycol (PEG), propylene glycol (PG), and citric acid (CA) using a 2k factorial experimental design to optimize their properties. HGs were characterized through FTIR and Raman spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The biological activities of HGs were determined by evaluating their mucoadhesive capacity and antibacterial activity in vitro, whereas their toxicity was analyzed using Artemia salina nauplii as an in vivo model. Results revealed that HGs were successfully optimized for their viscosity, pH, and sensory properties, and it was observed that varying concentrations of PEG-75 did not influence them. Through SEM analyses, it was noted that increased levels of PEG-75 resulted in HGs with distinct porosity and textures, whereas FTIR and Raman spectroscopy exhibited representative peaks of the raw materials used during the synthesis process. TGA studies indicated the thermal stability of HGs, as they presented degradation patterns at 100 and 300 °C. The synthesized HGs exhibited similar mucoadhesion kinetic profiles, demonstrating a displacement factor at an equilibrium of 0.57 mm/mg at 5 min. The antibacterial activity of HGs was appraised as poor against Gram-positive and Gram-negative bacteria due to their MIC90 values (>500 μg/mL). Regarding A. salina, treatment with HGs neither decreased their viability nor induced morphological changes. The obtained results suggest the suitability of CGG/PEG HGs for oral mucosa drug delivery and expand the knowledge about their mucoadhesive capacity, antibacterial potential, and in vivo biocompatibility.

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 cm ² , 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.

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.

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.

Being the first or second cause of death worldwide, cancer represents the most significant clinical, social, and financial burden of any human illness. Despite recent progresses in cancer diagnosis and management, traditional cancer chemotherapies have shown several adverse side effects and loss of potency due to increased resistance. As a result, one of the current approaches is on with the search of bioactive anticancer compounds from natural sources. Neopeltolide is a marine-derived macrolide isolated from deep-water sponges collected off Jamaica’s north coast. Its mechanism of action is still under research but represents a potentially promising novel drug for cancer therapy. In this review, we first illustrate the general structural characterization of neopeltolide, the semi-synthetic derivatives, and current medical applications. In addition, we reviewed its anticancer properties, primarily based on in vitro studies, and the possible clinical trials. Finally, we summarize the recent progress in the mechanism of antitumor action of neopeltolide. According to the information presented, we identified two principal challenges in the research, i) the effective dose which acts neopeltolide as an anticancer compound, and ii) to unequivocally establish the mechanism of action by which the compound exerts its antiproliferative effect.

The freeze-thaw (F/T) method is commonly employed during the processing and handling of drug substances to enhance their chemical and physical stability and obtain pharmaceutical applications such as hydrogels, emulsions, and nanosystems (e.g., supramolecular complexes of cyclodextrins and liposomes). Using F/T in manufacturing hydrogels successfully prevents the need for toxic cross-linking agents; moreover, their use promotes a concentrated product and better stability in emulsions. However, the use of F/T in these applications is limited by their characteristics (e.g., porosity, flexibility, swelling capacity, drug loading, and drug release capacity), which depend on the optimization of process conditions and the kind and ratio of polymers, temperature, time, and the number of cycles that involve high physical stress that could change properties associated to quality attributes. Therefore, is necessary the optimization of F/T conditions and variables. The current research regarding F/T is focused on enhancing the formulations, the process, and the use of this method in pharmaceutical, clinical, and biological areas. The present review aims to discuss different studies related to the impact and effects of the F/T process on the physical, mechanical, and chemical properties (porosity, swelling capacity) of diverse pharmaceutical applications with an emphasis on their formulation properties, the method and variables used, as well as challenges and opportunities in developing. Finally, we review the experimental approach for choosing the standard variables studied in the F/T method applying the systematic methodology of quality by design.