The physicochemical characterization of aqueous solutions of 4-O-methyl-D-glucurono-D-xylan (MGX), extracted from beech wood sawdust, has been conducted by Size Exclusion Chromatography (SEC) on-line coupled with Multi Angle Light Scattering (MALS) analyses. The chromatograms clearly evidence a strong aggregative behavior with the presence of two populations: the first one, less predominant (6.7–25 wt%), is made of large size structures, with number average molar mass (Mn) and mass average molar mass (Mw) higher than 10 6 g.mol − 1 , while the second one, more predominant (75–93.3 wt%), is made of chains displaying relatively lower molar masses. In this study, we demonstrate that suitable solvation conditions can be reached through heating at 80°C in pure water. In this case, the 2nd population accounts for 93.3 wt% of the sample, with molar masses of 22.700 and 36.900 g.mol − 1 respectively for Mn and Mw, corresponding to those from the literature obtained in non-aggregative conditions (i.e. DMSO or aqueous alkaline media). Conversely, stronger aggregation has been evidenced with lower solvation temperature, higher MGX concentration or in the presence of salts (notably with KCl). Finally, an unexpected cold gelation of semi-dilute concentrated MGX aqueous solution (150 g.L − 1 ) has been observed through rheology with a large hysteresis, characterized by a G’/G’’ crossing at 15.5°C when cooling and at 37.5°C when heating back to the initial temperature of 50°C.

Hemicellulose polymers are well-known for their applications in biology, but much less in the field of optics, and especially for their applications in fluorescence. On the other hand, original tetrazines that display intense fluorescence due to energy transfer from an absorbing "antenna" have been already described by some of us. In this study, we show that hemicellulose polymers are an host of choice for tetrazine fluorophores, likely due to their remaining locked within the hydrophobic nanodomains of the polymer, thus displaying an impressive increase in the emission quantum yield. We report an application to photon down-shifting in a classical organic solar cell (OSC), as well as an application of these highly emissive doped polymers.

Fibroblasts are considered a key player in the wound healing process. Although this cellular family is constituted by several distinct subtypes, dermal fibroblasts are crucial thanks to their ability to secrete pro-regenerative growth factors, extracellular matrix (ECM) proteins and their immune and anti-inflammatory role. Sophorolipids (SL), sophorosides (SS) and glucolipids (G), mono-unsaturated (C18:1) or saturated (C18:0), glycolipids derived from microbial fermentation of wild type or engineered yeast Starmerella bombicola, constitute a novel sustainable class of bio-based chemicals with interesting physicochemical characteristics, which allow them to form soft diverse structures from hydrogels to vesicles, micelles or complex coacervates with potential interest in skin regeneration applications. In this study, we first tested the cytocompatibility of a broad set of molecules from this family on normal human dermal fibroblasts (NHDF). Our results show that, up to an upper threshold (0.1 % w/v), the microbial glycolipids (SL-C18:1, G-C18:1, SSbola-C18:1, SL-C18:0 and G-C18:0) under study were able to sustain cell growth. Furthermore, we selected the least cytotoxic glycolipids (SL-C18:1, SSbola-C18:1, SL-C18:0) to study their potential to promote wound healing by measuring the gene expression of several key skin regeneration markers (i.e. collagen, elastin, transforming growth factor β, fibroblast growth factor …) using qPCR. Unfortunately, none of these glycolipids modulated the gene expression of molecules involved in tissue repair. However, this study aims to encourage the community to test this novel class of molecules for novel high-end biomedical applications. Importance:Biosurfactants prepared by microbial fermentation are natural amphiphiles of growing importance, with the goal of replacing synthetic surfactants in commercial formulations. However, their cytotoxicity profile is still poorly known, especially for new molecules like single-glucose lipids or bolaform sophorolipids. This wants to contribute to all those applications, which could be developed with biosurfactants in contact with the skin (cosmetics, wound healing). We test the cytotoxicity of five structurally-related molecules (C18:1 and C18:0 sophorolipids, C18:1 and C18:0 single-glucose lipids, C18:1 di-sophoroside) against normal human dermal fibroblasts (NHDF) and evaluate the metabolic activity of the least toxic among them. To the best of our knowledge, cytotoxicity of these molecules, and of microbial biosurfactants in general, was never tested against NHDF.

Myelin figures (MFs)-cylindrical lyotropic liquid crystalline structures consisting of concentric arrays of bilayers and aqueous media-arise from the hydration of the bulk lamellar phase of many common amphiphiles. Prior efforts have concentrated on the formation, structure, and dynamics of myelin produced by phosphatidylcholine (PC)-based amphiphiles. Here, we study the myelinization of glycolipid microbial amphiphiles, commonly addressed as biosurfactants, produced through the process of fermentation. The hydration characteristics (and phase diagrams) of these biological amphiphiles are atypical (and thus their capacity to form myelin) because unlike typical amphiphiles, their molecular structure is characterized by two hydrophilic groups (sugar, carboxylic acid) on both ends with a hydrophobic moiety in the middle. We tested three different glycolipid molecules: C18:1 sophorolipids and single-glucose C18:1 and C18:0 glucolipids, all in their nonacetylated acidic form. Neither sophorolipids (too soluble) nor C18:0 glucolipids (too insoluble) displayed myelin growth at room temperature (RT, 25 degrees C). The glucolipid C18:1 (G-C18:1), on the other hand, showed dense myelin growth at RT below pH 7.0. Examining their growth rates, we find that they display a linear L alpha t$$ L\ \alpha\ t $$ (L, myelin length; t, time) growth rate, suggesting ballistic growth, distinctly different from the L alpha t12$$ L\ \alpha\ {t}<^>{\frac{1}{2}} $$ dependence, characterizing diffusive growth such as what occurs in more conventional phospholipids. These results offer some insight into lipidic mesophases arising from a previously unexplored class of amphiphiles with potential applications in the field of drug delivery.

Robocasting stands as a pertinent additive manufacturing technique for producing intricate ceramic parts. Amidst stricter environmental regulations, the adoption of natural additives becomes imperative. This study investigates the influence of plant-based additives on the rheology and printability of eco-friendly pastes.Various 50 vol%-alumina pastes were formulated using natural binders, plasticizers and dispersants (e.g., lignosulfonate, polysaccharides, glycerol) and then assessed through oscillation and flow rheological analyses. Paste viscosity and rigidity often deviated from printability maps reported in the literature, showing the complexity of defining universal printability criteria. A comprehensive investigation was conducted on the water retention capabilities of additives, liquid phase migration and paste drying kinetics.This paper highlights the critical importance of constraining liquid phase migration within eco-friendly ceramic pastes and the crucial role of polymer chain reorientation under shear. Consequently, this research lays diversifying formulations, offering sustainable solutions for industrial ceramic applications.

Recently, we described porphyrin-based periodic mesoporous organosilica (PMO) nanoparticles synthesized from a large functional octatriethoxysilylated porphyrin precursor. The framework of the nanoparticles was formed by J-aggregates of porphyrins allowing two-photon excitation photodynamic therapy (TPE-PDT) and NIR imaging. In this study, we functionalized these PMO with polyethylene glycol (PEG) moieties and an analogue of mannose 6-phosphate functionalized on anomeric position (AMFA). These AMFA are known to efficiently target mannose 6-phosphate receptors (M6PR) which are over-expressed in various cancer cell lines (breast, prostate). Here we show that M6PR is also over-expressed in rhabdomyosarcoma (RMS) cell lines. We targeted this receptor with PMO-AMFA and efficiently performed TPE imaging and TPE-PDT of RMS cells. Furthermore the same treatment did not affect healthy myoblasts, which have a low expression of M6PR.

Context and objective In the context of valorization of wood waste from the timber industry, this work aims to study the chemical composition and to evaluate the biological capacities of coproducts from Pinus caribaea Morelet. Methods With this mind, sawdust, bark, and knot-wood from P caribaea were analyzed by high-performance liquid chromatography-mass spectrometry. The antioxidant activities of extracts and reference compounds were assessed in vitro using 2 methods: 2.2-diphenyl-1-picrylhydrazyl and 2.2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid). For antimicrobial evaluation, coproduct extracts were assayed against Staphylococcus aureus , Staphylococcus epidermidis , Escherichia coli , and Candida albicans . Results Despite the variable composition of sawdust, bark, and knot-wood, the composition of P caribaea is typical of the Pinus genus, with the presence of flavonoids, stilbenes, and lignans. Seven compounds were elucidated: 2 lignans (nortrachelogenin and matairesinol), 3 flavonoids (pinocembrin, pinobanksin, pinobanksin 3-acetate), 2 stilbenes (pinosylvin, pinosylvin monomethyl ether), and 1 phenolic acid (caffeic acid). Conclusion The ethanolic extracts of bark and knots showed significant antioxidant activity. The knots showed significant antibacterial properties against S epidermidis . Keywords , , coproducts , flavonoids , antiradical , antibacterial , bioactivity , ,

In the present work, we report on the synthesis of light-triggered antibacterial hydrogels, based on xylan chains covalently bound to meso-tetra(4-carboxyphenyl)porphyrin (TCPP). Not only does TCPP act as a photosensitizer efficient against Gram-positive bacteria, but it also serves as a cross-linking gelator, enabling the simple and easy building of xylan conjugate hydrogels. The hydrogels were characterized by infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), along with swelling and rheological tests. The antimicrobial activity of the hydrogels was tested under visible light irradiation against two Gram-positive bacterial strains, Staphylococcus aureus and Bacillus cereus. The preliminary results showed an interesting activity on these bacteria, indicating that these hydrogels could be of great potential in the treatment of skin bacterial infections with this species by photodynamic antimicrobial chemotherapy (PACT).

Context and objective In the context of valorization of wood waste from the timber industry, this work aims to study the chemical composition and to evaluate the biological capacities of coproducts from Pinus caribaea Morelet. Methods With this mind, sawdust, bark, and knot-wood from P caribaea were analyzed by high-performance liquid chromatography-mass spectrometry. The antioxidant activities of extracts and reference compounds were assessed in vitro using 2 methods: 2.2-diphenyl-1-picrylhydrazyl and 2.2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid). For antimicrobial evaluation, coproduct extracts were assayed against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Candida albicans. Results Despite the variable composition of sawdust, bark, and knot-wood, the composition of P caribaea is typical of the Pinus genus, with the presence of flavonoids, stilbenes, and lignans. Seven compounds were elucidated: 2 lignans (nortrachelogenin and matairesinol), 3 flavonoids (pinocembrin, pinobanksin, pinobanksin 3-acetate), 2 stilbenes (pinosylvin, pinosylvin monomethyl ether), and 1 phenolic acid (caffeic acid). Conclusion The ethanolic extracts of bark and knots showed significant antioxidant activity. The knots showed significant antibacterial properties against S epidermidis.

Context and objective In the context of valorization of wood waste from the timber industry, this work aims to study the chemical composition and to evaluate the biological capacities of coproducts from Pinus caribaea Morelet. Methods With this mind, sawdust, bark, and knot-wood from P caribaea were analyzed by high-performance liquid chromatography-mass spectrometry. The antioxidant activities of extracts and reference compounds were assessed in vitro using 2 methods: 2.2-diphenyl-1-picrylhydrazyl and 2.2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid). For antimicrobial evaluation, coproduct extracts were assayed against Staphylococcus aureus , Staphylococcus epidermidis , Escherichia coli , and Candida albicans . Results Despite the variable composition of sawdust, bark, and knot-wood, the composition of P caribaea is typical of the Pinus genus, with the presence of flavonoids, stilbenes, and lignans. Seven compounds were elucidated: 2 lignans (nortrachelogenin and matairesinol), 3 flavonoids (pinocembrin, pinobanksin, pinobanksin 3-acetate), 2 stilbenes (pinosylvin, pinosylvin monomethyl ether), and 1 phenolic acid (caffeic acid). Conclusion The ethanolic extracts of bark and knots showed significant antioxidant activity. The knots showed significant antibacterial properties against S epidermidis .

Bending rigidity, k, is classically measured for lipid membranes to characterize their nanoscale mechanical properties as a function of composition. Widely employed as a comparative tool, it helps understanding the relationship between the lipid's molecular structure and the elastic properties of its corresponding bilayer. Widely measured for phospholipid membranes in the shape of giant unilamellar vesicles (GUVs), bending rigidity is determined here for three self-assembled structures formed by a new biobased glucolipid bioamphiphile, rather associated to the family of glycolipid biosurfactants than phospholipids. In its oleyl form, glucolipid G-C18:1 can assemble into vesicles or crystalline fibers, while in its stearyl form, glucolipid G-C18:0 can assemble into lamellar gels. Neutron spin-echo (NSE) is employed in the q-range between 0.3 nm-1 (21 nm) and 1.5 nm-1 (4.1 nm) with a spin-echo time in the range of up to 500 ns to characterize the bending rigidity of three different structures (Vesicle suspension, Lamellar gel, Fiber gel) solely composed of a single glucolipid. The low (k = 0.30 ± 0.04 kbT) values found for the Vesicle suspension and high values found for the Lamellar (k = 130 ± 40 kbT) and Fiber gels (k = 900 ± 500 kbT) are unusual when compared to most phospholipid membranes. By attempting to quantify for the first time the bending rigidity of self-assembled bioamphiphiles, this work not only contributes to the fundamental understanding of these new molecular systems, but it also opens new perspectives in their integration in the field of soft materials.

Flavonoids are polyphenols with broad known pharmacological properties. A series of 2,3-dihydroflavanone derivatives were thus synthesized and investigated for their anti-inflammatory activities. The target flavanones were prepared through cyclization of 2′-hydroxychalcone derivatives, the later obtained by Claisen–Schmidt condensation. Since nitric oxide (NO) represents an important inflammatory mediator, the effects of various flavanones on the NO production in the LPS-induced RAW 264.7 macrophage were assessed in vitro using the Griess test. The most active compounds were flavanone (4G), 2′-carboxy-5,7-dimethoxy-flavanone (4F), 4′-bromo-5,7-dimethoxy-flavanone (4D), and 2′-carboxyflavanone (4J), with IC50 values of 0.603, 0.906, 1.030, and 1.830 µg/mL, respectively. In comparison, pinocembrin achieved an IC50 value of 203.60 µg/mL. Thus, the derivatives synthesized in this work had a higher NO inhibition capacity compared to pinocembrin, demonstrating the importance of pharmacomodulation to improve the biological potential of natural molecules. SARs suggested that the use of a carboxyl-group in the meta-position of the B-ring increases biological activity, whereas compounds carrying halogen substituents in the para-position were less active. The addition of methoxy-groups in the meta-position of the A-ring somewhat decreased the activity. This study successfully identified new bioactive flavanones as promising candidates for the development of new anti-inflammatory agents.

Bio-based hydrogels are attractive materials for many biomedical purposes such as drug delivery or wound healing. A light-triggered antibacterial activity can be conferred to hydrogels after their conjugation to appropriate photosensitizers (PS). In this study, we have synthesized and characterized hydrogels consisting of cationic porphyrin-xylan conjugates. A cationic porphyrin was covalently attached to xylan by an esterification reaction. Different porphyrin-xylan derivatives were obtained with degrees of substitution ranging from 0.003 to 0.053. Then, the derivatives were cross-linked after reaction with diethylenetriaminepentaacetic (DTPA) dianhydride to obtain the corresponding hydrogels. The study of the morphology and rheology of the hydrogels showed that the materials obtained present interconnected porous structures, good mechanical integrities as well as high swelling ratios. Antimicrobial activity of cationic porphyrin-xylan conjugate hydrogels was tested under white light irradiation against Staphylococcus aureus and Pseudomonas aeruginosa. All of the tested hydrogels showed photo-bactericidal activity against the two tested strains.

The potential of Pinus caribaea Morelet sawdust for the removal of nickel ions (Ni2+) and other metallic trace ions (Co2+, Cr3+, Mn2+) from aqueous solutions was investigated under batch conditions. Several parameters such as size of particles, contact time, pH, initial metal and biomass concentrations, desorption conditions and reusability were evaluated on natural biomass. Biosorption was fast, effective (73%) and biomaterial can be reused after five cycles. To enhance the removal capacity of nickel, pine sawdust was modified by acidic and oxidative treatments. Cellulosic residues from sawdust sequential extraction showed great biosorption capacity (96%). In the presence of a metal mixture, oxidized sawdust had better selectivity for Cr3+ ions than for Ni2+ . Pinus caribaea biomass could be an environmental, inexpensive and renewable material for the depollution of water laden with metallic trace elements.

Most photosensitizers (PS) suffer from a lack of water solubility and from a low selectivity toward tumor cells. Delivery systems using nanoparticles make it possible to improve PS water solubility, and also tumor targeting via the enhanced permeability and retention (EPR) effect. Among the organelles, mitochondria are attractive target sites for drug-delivery strategies since they perform a variety of key cellular processes. Our study was aimed at synthesizing nanoparticles consisting of xylan-carrying poi phyrins attached to a triphenylphosphonium moiety, in order to enhance the PDT effect through mitochondria' targeting. Hybrid nanoparticles were designed that consisted of a silica core coated with xylan substituted with porphyrin derivatives carrying a triphenylphosphonium moiety. These hybrid nanoparticles have been constructed, along with their counterparts devoid of silica core, taking into consideration the controversy surrounding the use of silica nanoparticles. Phototoxicity experiments, conducted against the HCT-116 and HT-29 colorectal cancer cell lines, showed that nanoparticles with porphyrins bearing a triphenylphosphonium moiety exhibited an enhanced photocytotoxic effect in comparison with free porphyrin or nanoparticles with porphyrins without the triphenylphosphonium moiety.

The poor solubility of most photosensitizers (PS) hampers their practical use as clinical agents. Conjugation of PS with water-soluble nanoparticles has been often used to bypass this hurdle. We describe in this study the extraction of glucuronoacetylxylan from chestnut sawdust, the hemisynthesis of pheophorbide-a (Pha) and its covalent attachment to xylan. The resulting conjugates (xyl-Pha) spontaneously form water-soluble spherical nanoparticles (xyl-Pha NPs) ranging between 100 and 250 nm in diameter. Assayed against the HT-29 colorectal cancer cell line, xyl-Pha NPs exhibited a dose-dependent phototoxicity only when irradiated with red light.

This work describes the preparation of concentrated alumina suspensions based on bio-sourced additives with a low environmental impact and with the rheological properties adapted to the tape casting process. Natural polysaccharides extracted from plants and fruits (pectin, psyllium…) were characterized (molar weight) and identified as promising binders for substituting the classical organic binders from petrochemical industry. The rheological behavior of the additives and of the suspensions containing these bio-sourced additives was studied in flow and in oscillations. The mechanical properties of the green tapes obtained with the different bio-sourced binders were determined from tensile experiment. This paper studies the relations between the nature of the binder, the rheological behavior of the suspension, the ability to tape cast the suspensions and the final properties of the green and sintered tapes.

Photodynamic therapy (PDT) using porphyrins has been approved for treatment of several solid tumors due to the generation of cytotoxic reactive oxygen species (ROS).www.videleaf.comHowever, low physiological solubility and lack of selectivity towards tumor sites are the main limitations of their clinical use.Nanoparticles are able to spontaneously accumulate in solid tumors through an enhanced permeability and retention (EPR) effect due to leaky vasculature, poor lymphatic drainage, and increased vessel permeability.Herein, we proved the added value of nanoparticle vectorization on anticancer efficacy and tumor-targeting by 5-(4-hydroxyphenyl)-10,15,20triphenylporphyrin (TPPOH).Using 80 nm silica nanoparticles (SNPs) coated with xylan-TPPOH conjugate (TPPOH-X), we first showed very significant phototoxic effects of TPPOH-X SNPs mediated by post-PDT ROS generation and stronger cell uptake in human colorectal cancer cell lines compared to free TPPOH.Additionally, we demonstrated apoptotic cell death induced by TPPOH-X SNPs-PDT and the interest of autophagy inhibition to increase anticancer efficacy.Finally, we highlighted in vivo, without toxicity, elevated anticancer efficacy of TPPOH-X SNPs through improvement of tumor-targeting compared to a free TPPOH protocol.Our work demonstrated for the first time the strong anticancer efficacy of TPPOH in vitro and in vivo and the merit of SNPs vectorization.

Photodynamic antimicrobial chemotherapy or PACT has been shown to be a promising antibacterial treatment that could overcome the challenge of multidrug-resistant bacteria. However, the use of most existing photosensitizers has been severely hampered by their significant self-quenching effect, poor water solubility, lack of selectivity against bacterial cells, and possible damage to the surrounding tissues. The use of hydrogels may overcome some of these limitations. We herein report a simple strategy to synthesize a cross-linked hydrogel from beech xylan. The hydrogel showed a high swelling ratio, up to 62, an interconnected porous structure, and good mechanical integrity, and 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetraiodide (TMPyP) was chosen as a model of hydrophilic photosensitizer (PS) and was encapsulated inside the xylan-based hydrogel. TMPyP-loaded hydrogel prolonged release of PS up to 24 h with a cumulative amount that could reach 100%. TMPyP-loaded hydrogel showed a photocytotoxic effect against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus strains, and Bacillus cereus, while no cytotoxicity was observed in the dark.