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The therapeutic effects of curcumin and its derivatives, based on research in recent years, are limited by their low bioavailability. To improve bioavailability and develop the medical field of application, different delivery systems have been developed that are adapted to certain environments or the proposed target type. This study presents some half-curcuminoids prepared by the condensation of acetylacetone with 4-hydroxybenzaldehyde (C1), 4-hydroxy-3-methoxybenzaldehyde (C2), 4-acetamidobenzaldehyde (C3), or 4-diethylaminobenzaldehyde (C4), at microwaves as a simple, solvent-free, and eco-friendly method. The four compounds obtained were characterized in terms of morphostructural and photophysical properties. Following the predictions of theoretical studies on the biological activities related to the molecular structure, in vitro tests were performed for compounds C1-C3 to evaluate the antitumor properties and for C4's possible applications in the treatment of neurological diseases. The four compounds were encapsulated in two types of hydrogel matrices. First, the alginate-glucosamine network was generated and then the curcumin analogs were loaded (G1, G3, G5-G7, and G9). The second type of hydrogels was obtained by loading the active compound together with the generation of the hydrogel carrier matrices, by simply dissolving (G4 and G10) or by chemically binding half-curcuminoid derivatives to glucosamine (G2 and G8). Thus, two types of curcumin analog delivery systems were obtained, which could be applied in various types of medical treatments.
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This work aims to evaluate the potential use of natural wastes (in particular, clam shells) to synthesize one of the most well-known and versatile materials from the phosphate mineral group, hydroxyapatite (HAP). The obtained material was characterized in terms of morphology and composition using several analytical methods (scanning electron microscopy-SEM, X-ray diffraction-XRD, X-ray fluorescence-XRF, Fourier transform infrared spectroscopy-FTIR, thermal analysis-TGA, and evaluation of the porosity and specific surface characteristics by the Brunauer-Emmett-Teller-BET method) in order to confirm the successful synthesis of the material and to evaluate the presence of potential secondary phases. The developed material was further doped with iron oxide (HAP-Fe) using a microwave-assisted method, and both materials were evaluated in terms of photocatalytic activity determined by the photodecomposition of methylene blue (MB) which served as a contaminant model. The best results (approx. 33% MB degradation efficiency, after 120 min. of exposure) were obtained for the hydroxyapatite material, superior to the HAP-Fe composite (approx. 27%). The utilization of hydroxyapatite obtained from clam shells underscores the importance of sustainable and eco-friendly practices in materials syntheses. By repurposing waste materials from the seafood industry, we not only reduce environmental impact, but also create a valuable resource with diverse applications, contributing to advancements in both healthcare and environmental protection.
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In the textile, medical, and food industries, many of the applications have targeted the use of textile fabrics with antimicrobial properties. Obtaining eco-friendly coatings is of wide interest, especially for applications related to wound dressing or to food packaging. In order to obtain coatings with antimicrobial properties through environmentally friendly methods, a series of experiments were carried out on the use of natural polymers loaded with silver nanoparticles. In this study, coatings with antimicrobial properties were obtained by depositing natural composites based on rice flour, carob flour, or alginate on cotton fabrics. These antimicrobial coatings were multicomponent systems, in which the host matrix was generated via hydration of natural polymers. The nanocomposite obtained from the phytosynthesis of silver particles in ginger extract was embedded in hydrogel matrices. The multicomponent gels obtained by embedding silver nanoparticles in natural polymer matrices were deposited on cotton fabric and were studied in relation to nanoparticles and the type of host matrix, and the antimicrobial activity was evaluated. Fabrics coated with such systems provide a hydrophilic surface with antimicrobial properties and can therefore be used in various areas where textiles provide antibacterial protection.
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Curcumin is a polyphenol of the Curcuma longa plant, which can be used for various medicinal purposes, such as inflammation and cancer treatment. In this context, two symmetric curcumin derivatives (D1-(1E,6E)-1,7-bis(4-acetamidophenyl)hepta-1,6-diene-3,5-dione and D2-p,p-dihydroxy di-cinnamoyl methane) were obtained by the microwave-based method and evaluated for their antitumoral effect on human cervix cancer in comparison with toxicity on non-tumoral cells, taking into account that they were predicted to act as apoptosis agonists or anti-inflammatory agents. The HeLa cell line was incubated for 24 and 72 h with a concentration of 50 µg/mL of derivatives that killed almost half of the cells compared to the control. In contrast, these compounds did not alter the viability of MRC-5 non-tumoral lung fibroblasts until 72 h of incubation. The nitric oxide level released by HeLa cells was higher compared to MRC-5 fibroblasts after the incubation with 100 µg/mL. Both derivatives induced the decrease of catalase activity and glutathione levels in cancer cells without targeting the same effect in non-tumoral cells. Furthermore, the Western blot showed an increased protein expression of HSP70 and a decreased expression of HSP60 and MCM2 in cells incubated with D2 compared to control cells. We noticed differences regarding the intensity of cell death between the tested derivatives, suggesting that the modified structure after synthesis can modulate their function, the most prominent effect being observed for sample D2. In conclusion, the outcomes of our in vitro study revealed that these microwave-engineered curcumin derivatives targeted tumor cells, much more specifically, inducing their death.
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Textile materials with fluorescent, repellent, or antimicrobial properties are increasingly used in common applications. Obtaining multi-functional coatings is of wide interest, especially for applications related to signaling or to the medical field. In order to increase the performance (color properties, fluorescence lifetime, self-cleaning or antimicrobial properties) of textile materials with special uses, a series of research was carried out regarding the modification of surfaces with nanosols. In this study, coatings with multiple properties were obtained by depositing nanosols on cotton fabrics generated through sol-gel reactions. These multifunctional coatings are hybrid materials in which the host matrix is generated using tetraethylorthosilicate (TEOS) and network modifying organosilanes:dimethoxydimethylsilane (DMDMS) or dimethoxydiphenylsilane (DMDPS) in a 1:1 mass ratio. Two curcumin derivatives were embedded in siloxane matrices, a yellow one (CY) that is identical to bis-demethoxycurcumin (one of the natural constituents in turmeric) and a red dye (CR) that has a N,N-dimethylamino group grafted in position 4 of the dicinnamoylmethane skeleton of curcumin. The nanocomposites obtained by embedding curcumin derivatives in siloxane matrices were deposited on cotton fabric and studied in relation to the dye and the type of host matrix. Fabrics coated with such systems provide a hydrophobic surface, have fluorescent and antimicrobial properties, change color depending on the pH, and therefore can be used in various fields where textiles provide signaling properties, self-cleaning, or antibacterial protection. The coated fabrics maintained their good multifunctional properties even after several washing cycles.
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The growing interest in materials derived from biomass has generated a multitude of solutions for the development of new sustainable materials with low environmental impact. We report here, for the first time, a strategy to obtain bio-based nanocomposites from epoxidized linseed oil (ELO), itaconic acid (IA), and surface-treated nanofibrillated cellulose (NC). The effect of nanofibrillated cellulose functionalized with silane (NC/S) and then grafted with methacrylic acid (NC/SM) on the properties of the resulted bio-based epoxy systems was thoroughly investigated. The differential scanning calorimetry (DSC) results showed that the addition of NCs did not influence the curing process and had a slight impact on the maximum peak temperature. Moreover, the NCs improved the onset degradation temperature of the epoxy-based nanocomposites by more than 30 °C, regardless of their treatment. The most important effect on the mechanical properties of bio-based epoxy nanocomposites, i.e., an increase in the storage modulus by more than 60% at room temperature was observed in the case of NC/SM addition. Therefore, NC's treatment with silane and methacrylic acid improved the epoxy-nanofiber interface and led to a very good dispersion of the NC/SM in the epoxy network, as observed by the SEM investigation. The dielectric results proved the suitability of the obtained bio-based epoxy/NCs materials as substitutes for petroleum-based thermosets in the fabrication of flexible electronic devices.
Asunto(s)
Celulosa , Nanocompuestos , Celulosa/química , Silanos , Metacrilatos , Nanocompuestos/química , Resinas Epoxi/químicaRESUMEN
In this research work, silica nanoparticles and silica-gentamicin nanostructured solution were synthesized by using the microwave-assisted synthesis, in basic medium, using two silane precursors (tetraethylorthosilicate and octyltriethoxysilane) and the antibiotic (gentamicin sulfate). The prepared materials were characterized through Fourier transform infrared (FTIR) spectroscopy, TGA analysis, transmission electron microscopy (TEM), and atomic force microscopy (AFM) to investigate the morphology and structure. Antimicrobial studies of the silica-gentamicin nanostructured solution versus silica nanoparticles were performed against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. FTIR spectra showed that the gentamicin has been loaded to the silica nanoparticles. AFM analysis showed that the morphology of the silica-gentamicin nanostructured solution has changed, and agglomerations of particles are present at the surface. Antimicrobial testing, performed using the diffusion method through spot inoculation, indicates that the silica-gentamicin nanostructured solution exhibited activity against the resistant strain. The obtained silica-gentamicin solution can be used as biochemical agent for the prevention and treatment of microorganisms which are deposited on different surfaces (e.g., glass, plastic, ceramic).
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Research in the field of natural dyes has constantly focused on methods of conditioning curcumin and diversifying their fields of use. In this study, hybrid materials were obtained from modified silica structures, as host matrices, in which curcumin dyes were embedded. The influence of the silica network structure on the optical properties and the antimicrobial activity of the hybrid materials was monitored. By modifying the ratio between phenyltriethoxysilane:diphenyldimethoxysilane (PTES:DPDMES), it was possible to evaluate the influence the organosilane network modifiers had on the morphostructural characteristics of nanocomposites. The nanosols were obtained by the sol-gel method, in acid catalysis. The nanocomposites obtained were deposited as films on a glass support and showed a transmittance value (T measured at 550 nm) of around 90% and reflectance of about 11%, comparable to the properties of the uncovered support. For the coatings deposited on PET (polyethylene terephthalate) films, these properties remained at average values of T550 = 85% and R550 = 11% without significantly modifying the optical properties of the support. The sequestration of the dye in silica networks reduced the antimicrobial activity of the nanocomposites obtained, by comparison to native dyes. Tests performed on Candida albicans fungi showed good results for the two curcumin derivatives embedded in silica networks (11-18 mm) by using the spot inoculation method; in comparison, the alcoholic dye solution has a spot diameter of 20-23 mm. In addition, hybrids with the CA derivative were the most effective (halo diameter of 17-18 mm) in inhibiting the growth of Gram-positive bacteria, compared to the curcumin derivative in alcoholic solution (halo diameter of 21 mm). The results of the study showed that the presence of 20-40% by weight DPDMES in the composition of nanosols is the optimal range for obtaining hybrid films that host curcumin derivatives, with potential uses in the field of optical films or bioactive coatings.