FT-IR characterization of antimicrobial hybrid materials through sol-gel synthesis

Silica/polycaprolactone and titania/polycaprolactone hybrid organic/inorganic amorphous composites were prepared via a sol-gel method starting from a multi-element solution containing tetramethyl orthosilicate (TMOS) or titanium butoxide (TBT), polycaprolactone (PCL), water and methylethylketone (MEK). The molecular structure of the crosslinked network was based on the presence of the hydrogen bonds between organic/inorganic elements as confirmed by Fourier Transform Infra-Red (FT-IR) analysis. In particular, the structure of crosslinked network was realized by hydrogen bonds between the X-OH (X = Si or Ti) group (H donator) in the sol-gel intermediate species and ester groups (H-acceptors) in the repeating units of the polymer. The morphology of the hybrid materials; pore size distribution, elemental homogeneity and surface features, was studied by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) and by atomic force microscopy (AFM). The bioactivity of the synthesized hybrid materials was confirmed by observing the formation of a layer of hydroxyapatite (HAP) on the surface of the samples soaked in a simulated body fluid. The antimicrobial behavior of synthetized hybrids was also assessed against Escherichia coli bacteria. In conclusion, the prepared hybrid materials are proposed for use as future bone implants

Caratterizzazione del sistema attivatore del plasminogeno nella progressione metastatica del cancro prostatico umano

GnRH analogues are used for the treatment of prostate cancer (PCa) because their ability to suppress the activity of the pituitary-testicular axis, with consequent blockade of testosterone production. However, after an initial responsiveness to hormonal deprivation, PCa progresses and then metastatises. It is known that the system of the plasminogen activator (uPA, uPA inhibitors PAI-1/2 and uPA receptor, uPAR) has been involved in the local degradation of the extracellular matrix and PCa progression and metastases. Studies performed in our laboratory have demonstrated the presence of GnRH receptors, suggesting a direct effect of GnRH analogues in inhibiting the proliferation of human PCa cell lines. The aim of this study was to test the effect of an agonist (Leuprolide) and an antagonist (Cetrorelix) of GnRH on uPA/uPAR and PAI-1 expression and activity, on the migratory and invasion capabilities in the two androgen-independent cell lines, DU145 and PC3 cells. The results obtained in DU145 and PC3 cells show that both Leuprolide and Cetrorelix: 1) significantly decrease the enzymatic activity of uPA; 2) induce a marked decrease of uPA and a significant increase of PAI-1 protein levels; 3) increase the presence of soluble uPAR in the cell media; 4) decrease the migratory and invasion capabilities. In conclusions, GnRH analogues might interfere with the mechanisms of metastatic progression of human androgen-independent PCa by inhibiting the activity of the plasminogen activator system

Physicochemical Properties of PEG-Based Inorganic Hybrids Obtained via Sol-Gel

Organic-inorganic composites can be conveniently obtained by sol-gel recipes. They can find interesting applications in several fields, including drug delivery, scaffolding, bio-sensing, energetics, etc. Herein, we reconsider and reinvestigate our previous work in the field, by considering the sol-gel synthesis and physicochemical characterization of class-I organic-inorganic hybrids, and by trying to highlight some unifying elements that can be of help for the development of more efficient and precise synthesis methods. Systems based on poly(ethylene glycol) with SiO2 and ZrO2 as the ceramic phase will be discussed. Emphasis will be put on the role played by solid-state NMR spectroscopy in unveiling the interactions at the base of hybrid formation

Dexamethasone blocks the migration of the human neuroblastoma cell line SK-N-SH

Glucocorticoids (Gc) influence the differentiation of neural crestderived cells such as those composing sympathoadrenal tumors like pheochromocytomas, as well as neuroblastomas and gangliomas. In order to obtain further information on the effects of Gc on cells evolving from the neural crest, we have used the human neuroblastoma cell line SK-N-SH to analyze: 1) the presence and the binding characteristics of Gc receptors in these cells, 2) the effect of dexamethasone (Dex) on the migration of SK-N-SH cells, and 3) the effect of Dex on the organization of the cytoskeleton of SK-N-SH cells. We show that: 1) receptors that bind [ 3 H]-Dex with high affinity and high capacity (Kd of 9.6 nM, Bmax of 47 fmol/mg cytosolic protein, corresponding to 28,303 sites/cell) are present in cytosolic preparations of SK-N-SH cells, and 2) treatment with Dex (in the range of 10 nM to 1 µM) has an inhibitory effect (from 100% to 74 and 43%, respectively) on the chemotaxis of SK-N-SH cells elicited by fetal bovine serum. This inhibition is completely reversed by the Gc receptor antagonist RU486 (1 µM), and 3) as demonstrated by fluorescent phalloidin-actin detection, the effect of Dex (100 nM) on SK-NSH cell migration is accompanied by modifications of the cytoskeleton organization that appear with stress fibers. These modifications did not take place in the presence of 1 µM RU486. The present data demonstrate for the first time that Dex affects the migration of neuroblastoma cells as well as their cytoskeleton organization by interacting with specific receptors. These findings provide new insights on the mechanism(s) of action of Gc on cells originating in the neural crest

Cytocompatibility of Caffeic Acid-Silica Hybrid Materials on NIH-3T3 Fibroblast Cells

The hydroxycinnamoyl compound caffeic acid (CA), broadly occurring in plants, is receiving special attention in materials science thanks to its antioxidant, anti-inflammatory, and antimicrobial activities that make it promising for application use in various sectors. In this context, CA–based peptide biomaterials are recently developed as eco-friendly and multifunctional free radical scavengers useable in a wide range of consumer manufacture, ranging from cosmetics to household products, as well as clinical applications, including imaging, drug delivery, and disinfection. Furthermore, a water-soluble chitosan-caffeic acid conjugate, effective in delaying lipid oxidation, is also synthetized. Herein, exploiting sol-gel route versatility, CA/silica materials are synthetized. Hybrids, chemically characterized mainly through spectroscopic techniques, varied in their relative CA content, which represented 5%, 10%, 15%, or 20% of materials’ weight. The synthetized materials are able to elicit anti-radical properties. The CA amount appeared to be determinant in anti-radical activity, as well as in biocompatibility assessment. To this latter purpose, mouse embryonic fibroblast cell line NIH-3T3 cells are utilized and directly exposed to hybrid materials. Redox mitochondrial activity is evaluated by means of the MTT test, whose results are in accordance with the materials’ biocompatibility

Thermal Influence on Physico-Chemical Properties of Geopolymers Based on Metakaolin and Red Tomato Waste

The high amount of organic and inorganic wastes has increased the attention to new strategies aiming to reduce the waste disposals. Organic wastes, such as tomato wastes (TWs), are a good source from which the red color can be obtained. Among the different technologies, the geopolymers had been proposed as a powerful technology able to incorporate various kinds of wastes. In this paper, pure metakaolin and a mixture obtained by adding 10% of red TW-derived (peels) are consolidated by alkali activation at room temperature, 40 and 60°C without the pigment extraction. Fourier-transform infrared (FTIR) spectra confirmed the geopolymerization occurrences. Moreover, the obtained materials are analyzed for their conductivity and pH after the sample extractions at different times. The integrity tests assessed the resistance of the synthesized geopolymers and the presence of red tomato-wastes led to a release of yellow organic hydro-soluble compounds. Finally, the weight loss confirmed the integrity test. Indeed, there are no differences at 16 and 30 d

Influence of the addition of waste glass and microbiological performance of metakaolin-based geopolymers cement

Abstract. Glass recycling reduces the amount of waste to be treated or disposed in landfills, allowing both to limit environmental damage and to save on the costs of transportation and disposal of waste. In this paper, an advantageous method for recycling glass containers (bottles, jars, jars for food, glasses and cans for drinks, etc.) is presented. The glass was crushed and without being washed or separated from any foreign bodies it was safely incorporated into a metakaolin-based geopolymeric matrix. Pure metakaolin and mixtures obtained by adding different percentages (30-50 wt%) of glass cullet were consolidated via alkali activation at 50°C. Infrared spectroscopy was able to reveal the formation of bonds in the mixtures between the geopolymeric matrix and the glass. Leaching tests were carried out to evaluate the eventual release of toxic metals, while the antibacterial tests completed the environmental evaluation of the final consolidated products that showed how the mechanical performance were modified by adding different amount of glass [1]. References [1] G. Dal Poggetto, M. Catauro, G. Crescente and C. Leonelli. Efficient addiction of waste glass in MK-based geopolymers: microstructure, antibacterial and cytotoxicity investigation. Polymers, 2021, 13, 1493

Thermal influence on physico-chemical properties of metakaolin/organic-based geopolymers

Abstract. The high amount of organic and inorganic wastes has increased the attention to new strategies aiming to reduce the waste disposals. Among the different technologies, the geopolymers had been proposed as a powerful technology able to incorporate various kind of wastes [1]. Pure metakaolin and a mixture obtained by adding 10% of tomato waste-derived were consolidated by alkali activation at room temperature, 40 and 60°C. FT-IR spectra confirmed the geopolymerization occurrences. Conductivity and pH were evaluated at different time. The integrity tests assessed the resistance of the synthesized geopolymers and the presence of tomato-wastes led to a release of yellow organic hydro-soluble compound. Weight loss confirmed the integrity test, indeed there were no differences at 16 and 30 days. Finally, the antibacterial properties of the synthesized geopolymers were investigated [2]. References [1] H.K. Tchakouté, C.H. Rüscher, S. Kong, E. Kamseu, C. Leonelli, Constr Build Mater. 2016, 114, 276 – 289 [2] G. Dal Poggetto, M. Catauro, G. Crescente, C. Leonelli, Polymer. 2021, 13, 149

Influence of the Addition of Waste Glass and Microbiological Performance of Metakaolin-Based Geopolymers Cement

Glass recycling reduces the amount of waste to be treated or disposed in landfills, allowing both to limit environmental damage and to save on the costs of transportation and disposal of waste. In this paper, an advantageous method for recycling glass containers (bottles, jars, jars for food, glasses, and cans for drinks, etc.) is presented. The glass is crushed and without being washed or separated from any foreign bodies it is safely incorporated into a metakaolin (MK)-based geopolymeric matrix. Pure MK and mixtures obtained by adding different percentages (30–50 wt%) of glass cullet are consolidated via alkali activation at 50°C. Infrared spectroscopy is able to reveal the formation of bonds in the mixtures between the geopolymeric matrix and the glass. Leaching tests are carried out to evaluate the eventual release of toxic metals, while the antibacterial tests complete the environmental evaluation of the final consolidated products that show how the mechanical performance are modified by adding different amount of glass cullet

Antioxidants in Animal Nutrition: UHPLC-ESI-QqTOF Analysis and Effects on In Vitro Rumen Fermentation of Oak Leaf Extracts

: The genus Quercus supplies a large amount of residual material (e.g., bark, acorns, leaves, wood), the valorization of which can favor a supply of antioxidant polyphenols to be used in the pharmaceutical, nutraceutical, or cosmeceutical sector. The recovery of specialized metabolites could also benefit livestock feeding, so much so that polyphenols have gained attention as rumen fermentation modifiers and for mitigating the oxidative imbalance to which farm animals are subject. In this context, leaves of Quercus robur L. from Northern Germany were of interest and the alcoholic extract obtained underwent an untargeted profiling by means of ultra-high-performance liquid chromatography/high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) techniques. As triterpenes and fatty acids occurred, the alcoholic extract fractionation pointed out the obtainment of a polyphenol fraction, broadly constituted by coumaroyl flavonol glycosides and condensed tannins. Total phenol, flavonoid and condensed tannins content assays, as well as antiradical (DPPH● and ABTS+●) and reducing activity (PFRAP) were carried out on the alcoholic extract and its fractions. When the effects on rumen liquor was evaluated in vitro in terms of changes in fermentation characteristics, it was observed that oak leaf extract and its fractions promoted an increase in total volatile fatty acids and differently modulated the relative content of each fatty acid