Fructose/glycerol/water as a biosourced LTTM solvent to design a variety of sodium alginate-based soft materials with enhanced rheological properties

Sodium alginate was associated to a ternary solvent composed of fructose, glycerol, and water in a 1:1:5 M ratio (FGW), classified as a natural Low Transition Temperature Mixture (LTTM), to generate various soft materials. The rheological properties of mixtures composed of sodium alginate and FGW were thoroughly analyzed and compared to their aqueous analogues. FGW-based solutions present a pronounced shear-thinning character combined to high viscosity, up to 8000 Pa.s. The overlap concentrations and intrinsic viscosities values evidence a good solvent character of FGW for alginate polymer chains. The increase of alginate concentration in FGW leads to materials with enhanced elasticity (up to 6000 Pa) and high energy of activation (55 kJ/mol). Interestingly, the addition of divalent calcium cations in FGW according to two optimized experimental protocols, allows for the generation of never described ionotropic gels in FGW under various shapes as bulk gels or beads of gels able to encapsulate extracted vegetal actives that are used in the cosmetic industry. Thus, FGW appears as a well-suited solvent of alginate to design a broad range of new biobased soft materials.

α-Substituted ketones as reagent for Passerini modification of carboxymethyl cellulose: Toward dually functionalized derivatives and thermo-sensitive chemical hydrogels

The present works describes the Passerini modification of carboxymethyl cellulose (CMC) by using a library of nine α-substituted ketones derivatives, differing in their hydrophobicity and reactivity, conjointly with cyclohexyl isocyanide. The Passerini ligation, achieved in aqueous and mild conditions, was shown to be successful, leading to a large panel of dually functionalized CMC derivatives, in an eco-friendly manner. A particular attention was dedicated to the influence of the experimental parameters such as the stoichiometry, the nature of a co-solvent or the temperature, which allowed to tune the extent of modification. The reactivity of the ketone was proven to be governed by its i) compatibility with water, ii) sterical accessibility, and by iii) the presence of neighboring electron-withdrawing group. The resulting Passerini CMC products modified by methacrylate moieties (CMC-MA) were used as reactive macromonomer under a "grafting through" approach. The copolymerization of CMC-MA with oligoethylene glycol methacrylate (OEGMA) and diethylene glycol methacrylate (DEGMA) upon thermal radical reaction conditions enabled to generate tightly cross-linked chemical hydrogels, with a thermo-sensitive and thermo-reversible behavior, reflected by a macroscopical shrinkage/swelling response, and confirmed by SAXS analysis. Such chemical strategy paves the way toward multifunctional polysaccharide-based networks with potential utilizations as drug delivery devices, dye removals or actuators.

Fluorescent Polymer-AS1411-Aptamer Probe for dSTORM Super-Resolution Imaging of Endogenous Nucleolin

Nucleolin is a multifunctional protein involved in essential biological processes. To precisely localize it and unravel its different roles in cells, fluorescence imaging is a powerful tool, especially super-resolution techniques. Here, we developed polymer-aptamer probes, both small and bright, adapted to direct stochastic optical reconstruction microscopy (dSTORM). Well-defined fluorescent polymer chains bearing fluorophores (AlexaFluor647) and a reactive end group were prepared via RAFT polymerization. The reactive end-group was then used for the oriented conjugation with AS1411, a DNA aptamer that recognizes nucleolin with high affinity. Conjugation via strain-promoted alkyne/azide click chemistry (SPAAC) between dibenzylcyclooctyne-ended fluorescent polymer chains and 3'-azido-functionalized nucleic acids proved to be the most efficient approach. In vitro and in cellulo evaluations demonstrated that selective recognition for nucleolin was retained. Their brightness and small size make these polymer-aptamer probes an appealing alternative to immunofluorescence, especially for super-resolution (10-20 nm) nanoscopy. dSTORM imaging demonstrated the ability of our fluorescent polymer-aptamer probe to provide selective and super-resolved detection of cell surface nucleolin.

Three-dimensional MRI-based treatment planning approach for non-invasive ocular proton therapy

PURPOSE

To develop a high-resolution three-dimensional (3D) magnetic resonance imaging (MRI)-based treatment planning approach for uveal melanomas (UM) in proton therapy.

MATERIALS/METHODS

For eight patients with UM, a segmentation of the gross tumor volume (GTV) and organs-at-risk (OARs) was performed on T1- and T2-weighted 7 Tesla MRI image data to reconstruct the patient MR-eye. An extended contour was defined with a 2.5-mm isotropic margin derived from the GTV. A broad beam algorithm, which we have called πDose, was implemented to calculate relative proton absorbed doses to the ipsilateral OARs. Clinically favorable gazing angles of the treated eye were assessed by calculating a global weighted-sum objective function, which set penalties for OARs and extreme gazing angles. An optimizer, which we have named OPT'im-Eye-Tool, was developed to tune the parameters of the functions for sparing critical-OARs.

RESULTS

In total, 441 gazing angles were simulated for every patient. Target coverage including margins was achieved in all the cases (V95%  > 95%). Over the whole gazing angles solutions space, maximum dose (Dmax ) to the optic nerve and the macula, and mean doses (Dmean ) to the lens, the ciliary body and the sclera were calculated. A forward optimization was applied by OPT'im-Eye-Tool in three different prioritizations: iso-weighted, optic nerve prioritized, and macula prioritized. In each, the function values were depicted in a selection tool to select the optimal gazing angle(s). For example, patient 4 had a T2 equatorial tumor. The optimization applied for the straight gazing angle resulted in objective function values of 0.46 (iso-weighted situation), 0.90 (optic nerve prioritization) and 0.08 (macula prioritization) demonstrating the impact of that angle in different clinical approaches.

CONCLUSIONS

The feasibility and suitability of a 3D MRI-based treatment planning approach have been successfully tested on a cohort of eight patients diagnosed with UM. Moreover, a gaze-angle trade-off dose optimization with respect to OARs sparing has been developed. Further validation of the whole treatment process is the next step in the goal to achieve both a non-invasive and a personalized proton therapy treatment.

All poly(ionic liquid) block copolymer nanoparticles from antagonistic isomeric macromolecular blocks via aqueous RAFT polymerization-induced self-assembly

All-poly(ionic liquid) block copolymer nanoparticles are prepared by aqueous RAFT PISA using a couple of isomeric ionic liquid monomers leading to macromolecular building blocks with antagonistic solution behavior in water.

Biobased poly(ester-co-glycoside) from reactive natural Brønsted acidic deep eutectic solvent analogue

{glucose : malic acid : water} [(1 : 1 : x), x ≤ 9] mixtures are Brønsted Acidic Natural Low Transition Temperature (NaLTTM) that react in solvent/catalyst free conditions to prepare all-natural poly(ester-co-glycoside) branched and crosslinked polymers.

Zwitterionic Silicone Materials Derived from Aza-Michael Reaction of Amino-Functional PDMS with Acrylic Acid

Supramolecular zwitterionic silicones are synthesized by aza-Michael reaction between acrylic acid and amine-functional polydimethylsiloxanes. The in-depth characterization of this chemistry, applied for the first time to silicones, is investigated first with model alkylamines (hexylamine, 2-ethylhexylamine and N-propylethylenediamine), a model oligosiloxane (3-aminopropylmethyl bis(trimethylsiloxy)silane), and finally various amino-polysiloxanes. It is shown that after a first acid-base reaction resulting in ionic pairing, aza-Michael addition proceeds smoothly in mild conditions (50 °C, 1-week reaction). Both monoadducts and di-adducts, together with residual amine, are observed by NMR. The supramolecular assembly of the thus-created zwitterionic moieties is highlighted by a concomitant increase in viscosity and phase separation, as observed by transmission electron microscopy, bringing an additional glass transition at -40 °C assigned to highly polar ionic clusters. Below the stoichiometry in acrylic acid, all zwitterionic silicones follow the same classical behavior of nonentangled polymers according to the Rouse model, whereas upon introducing an excess of acrylic acid to amino groups, an enhancement of the elasticity is observed. Finally, silicone elastomers with solid-like behavior and elastomeric mechanical properties are obtained using a high molar mass polymer bearing bifunctional N-(2-aminoethyl)-3-aminopropyl units that favor a high degree of physical crosslinking.

Solvent-Free Synthesis of Amidated Carboxymethyl Cellulose Derivatives: Effect on the Thermal Properties

The present work explores the possibility of chemically modifying carboxymethyl cellulose (CMC), a widely diffused commercial cellulose ether, by grafting of hydrophobic moieties. Amidation of CMC, at high temperature and in heterogeneous conditions, was selected as synthetic tool for grafting on CMC a panel of commercially available amines (bearing long aliphatic chains, alkyl aromatic and heteroaromatic groups, more or less spaced from the cellulose backbone). The reaction was successfully carried out in absence of solvents, catalysts and coupling agents, providing a promising and more sustainable alternative to conventional amidation procedures. Relationships between the chemical structure of the obtained CMC derivatives and their thermal properties were carefully studied, with a particular attention to the thermal behavior. Grafting of aromatic and heteroaromatic alkyl amines, presenting a linear alkyl chain between CMC backbone and a terminal bulky moiety, allowed for efficiently separating the polysaccharide chains, improving their mobility and resulting in a consequent lowering of the glass transition temperature (T_g). The T_g values obtained (90-147 °C) were found to be closely dependent on both the size of the aliphatic spacer, the structure of the aromatic ring and the extent of amidation.

Going beyond the barriers of aza-Michael reactions: controlling the selectivity of acrylates towards primary amino-PDMS

End-group modification of 1° amino-PDMS through metal-catalyst-free aza-Michael addition is controlled by monitoring the operation conditions.

A library of heptyl mannose-functionalized copolymers with distinct compositions, microstructures and neighboring non-sugar motifs as potent antiadhesives of type 1 piliated E. coli

Heptyl Mannose-functionalized copolymers are efficient anti-adhesives of type 1 Piliated E. coli.

Sweet supramolecular elastomers from α,ω-(β-cyclodextrin terminated) PDMS

CDs linked to PDMS vaturally phase separate and hydrogen bond to generate supramolecular elastomers.

Aqueous RAFT Polymerization of Imidazolium-Type Ionic Liquid Monomers: En Route to Poly(ionic liquid)-Based Nanoparticles through RAFT Polymerization-Induced Self-Assembly

The synthesis by aqueous RAFT polymerization of hydrophilic narrowly dispersed imidazolium-based poly(ionic liquid)s (Đ typically below 1.20) is reported. Full monomer conversion is achieved within hours and high end-group fidelity of the living end groups affords the preparation of well-defined block copolymers. The resulting poly(ionic liquid) macroRAFT agents are finally exploited to polymerize 2-vinylpyridine in water and generate PIL-based nanoparticles of various morphologies (spheres, vesicles, or worms) in a one-pot surfactant-free process.

Glycopolymers as Antiadhesives of E. coli Strains Inducing Inflammatory Bowel Diseases

n-Heptyl α-d-mannose (HM) is a nanomolar antagonist of FimH, a virulence factor of E. coli. Herein we report on the construction of multivalent HM-based glycopolymers as potent antiadhesives of type 1 piliated E. coli. We investigate glycopolymer/FimH and glycopolymer/bacteria interactions and show that HM-based glycopolymers efficiently inhibit bacterial adhesion and disrupt established cell-bacteria interactions in vitro at very low concentration (0.1 μM on a mannose unit basis). On a valency-corrected basis, HM-based glycopolymers are, respectively, 10(2) and 10(6) times more potent than HM and d-mannose for their capacity to disrupt the binding of adherent-invasive E. coli to T84 intestinal epithelial cells. Finally, we demonstrate that the antiadhesive capacities of HM-based glycopolymers are preserved ex vivo in the colonic loop of a transgenic mouse model of Crohn's disease. All together, these results underline the promising scope of HM-based macromolecular ligands for the antiadhesive treatment of E. coli induced inflammatory bowel diseases.

Flame retardant lignin-based silicone composites

The use of lignin as a filler for polymers to give composites provides both economic advantages and, in some cases, improved flame retardancy and mechanical performance.

Dip- and spin-assisted stereocomplexation-driven LbL self-assembly involving homochiral PVA-g-OLLA and PVA-g-ODLA copolymers

Layer by Layer (LbL) thin films stemming from the formation of stereocomplex between oligolactate with opposite chirality (OLLA and ODLA) covalently anchored onto poly(vinyl alcohol) (PVA) chains is described herein for the first time.

Brilliant glyconanocapsules for trapping of bacteria

n-Heptyl α-d-mannose-functionalized nanocapsules are prepared by the Shift'N'Go process and post-modified to ensure aggregation and efficient removal of bacteria.

Silicone-based surfactant degradation in aqueous media

The increasing use of surfactants, such as modified polydimethylsiloxane-graft-polyethylene oxide (PDMS-g-PEO), requires studies on the fate of these compounds in the environment, and in particular in wastewater systems. A kinetic study, performed under three different pH conditions (pH2, 5.3 and 11) and using (1)H NMR (Nuclear Magnetic Resonance), proves that hydrolysis of the siloxane chain takes place in all cases, with higher rates for the two extreme conditions. Steric exclusion chromatography (SEC) clearly showed a decrease in the average molecular weight of the copolymer leading to a new molecular weight distribution, especially in acidic conditions. Degradation products, analyzed by (29)Si NMR, were found to be similar whatever the degradation pathway, namely silanediols and cyclic volatile compounds (degradation products of PDMS) and also PEO-modified silanediols and cyclic compounds. After one year, the siloxane chain completely disappeared under acidic conditions. Real wastewater medium has a strong effect on polymer stability, indicating that pH is not the only parameter which influences degradation rate.