Fostering sustainability of Community Networks: Guidelines to Respect the European Legal Framework

International audienceThis chapter proposes guidelines to help Community Networks (CNs) to cope with the applicable European legal framework and mitigate legal risks while protecting users' rights and enforcing core values such as privacy. It covers three main topics that are key to the activity of CNs: civil liability, data protection, data retention and provides concrete recommendations on the legal choices to be made, as well as suggestions for CN governance choices. The chapter is based on the analysis of the legislation and case law applicable to 'electronic communications services', 'electronic communications network', and 'services providers' of an 'information society service'. The legal analysis was informed by a survey, which gathered replies on the practices of CNs from six EU countries (France, Italy, Germany, Greece, Portugal and Slovenia) in five main areas: organization, services offered, relationship with users, data protection and data retention law. The chapter presents our findings and recommendations in the areas of civil liability, data protection law, data retention, and makes governance recommendations to address these challenges and mitigate CNs legal risks

Functionalized polysaccharides with aminoguaiacol : a competition between associative behavior and antibacterial and antioxidant activities

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A novel amphiphilic pH-sensitive hydrogel based on pullulan

International audienceNovel polyelectrolyte and amphiphilic hydrogels based on pullulan have been prepared using 1-ethyl-3-[3-(dimethylamino)-propyl]carbodiimide hydrochloride and N-hydroxysuccinimide. The cross-linking reaction is fast and lead to zero length ester cross-links by the reaction of a carboxylate group with an alcohol function of the polysaccharide. The charge density and the hydrophobic rate of the precursor carboxymethylpullulan (CMP) are controlled during the carboxymethylation of pullulan and the grafting reaction of octyl chains on CMP, respectively. The grafting degree influences the conformation of the hydrophobically modified CMP (HMCMP) in solution and leads to the formation of hydrophobic clusters firstly in the HMCMP solutions and further in the HMCMP hydrogels. The swelling measurements of HMCMP hydrogels at different salt concentrations (0–0.2 M NaCl) and different pH (3–11) shows the ionic strength and pH sensitivity of the gels. The loading of a hydrophobic probe molecule can be controlled by the grafting degree of HMCMP hydrogels

Hyaluronic Acid Functionalization with Jeffamine® M2005: A Comparison of the Thermo-Responsiveness Properties of the Hydrogel Obtained through Two Different Synthesis Routes

International audienceHyaluronic acid (HA) of different molar masses (respectively 38,000, 140,000 and 1,200,000 g.mol−1) have been functionalized with a commercial poly(etheramine), Jeffamine® M2005, in order to devise physical thermo-responsive hydrogels. Two routes have been studied, involving the use of either water for the first one or of N,N′-Dimethylformamide (DMF), a polar aprotic solvent, for the second one. In the case of the water route, the reaction was performed using a mixture of N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) as coupling reagents. The reaction was optimized while making sure no free M2005 remained in the final material, leading to M2005 grafting degrees of about 4%, which enabled the formation of hydrogels by increasing the temperature. In the case of the organic solvent route, propylphosphonic anhydride T3P® was used as a coupling reagent in DMF, resulting in a M2005 grafting degree of around 8% with better thermo-responsive properties of HA-g-M2005 compared to those obtained when the reaction was performed in water. However, the reaction systematically led to covalent cross-linking in the case of the HA, with the highest starting molar masses resulting in a very different rheological behaviour and with higher gel strength retaining thermo-responsive behaviour but being only poorly soluble in water

Hydrogels Based on Polysaccharides Grafted Ferulic Acid: A Biomimetic Approach

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Polyelectrolyte complexes of hyaluronic acid and diethylaminoethyl dextran: Formation, stability and hydrophobicity

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Thermoresponsive nanogels based on polyelectrolyte complexes between polycations and functionalized hyaluronic acid

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Lyophilization for Formulation Optimization of Drug-Loaded Thermoresponsive Polyelectrolyte Complex Nanogels from Functionalized Hyaluronic Acid

International audienceThe lyophilization of nanogels is practical not only for their long-term conservation but also for adjusting their concentration and dispersant type during reconstitution for different applications. However, lyophilization strategies must be adapted to each kind of nanoformulation in order to minimize aggregation after reconstitution. In this work, the effects of formulation aspects (i.e., charge ratio, polymer concentration, thermoresponsive grafts, polycation type, cryoprotectant type, and concentration) on particle integrity after lyophilization and reconstitution for different types of polyelectrolyte complex nanogels (PEC-NGs) from hyaluronic acid (HA) were investigated. The main objective was to find the best approach for freeze-drying thermoresponsive PEC-NGs from Jeffamine-M-2005-functionalized HA, which has recently been developed as a potential platform for drug delivery. It was found that freeze-drying PEC-NG suspensions prepared at a relatively low polymer concentration of 0.2 g.L−1 with 0.2% (m/v) trehalose as a cryoprotectant allow the homogeneous redispersion of PEC-NGs when concentrated at 1 g.L−1 upon reconstitution in PBS without important aggregation (i.e., average particle size remaining under 350 nm), which could be applied to concentrate curcumin (CUR)-loaded PEC-NGs for optimizing CUR content. The thermoresponsive release of CUR from such concentrated PEC-NGs was also reverified, which showed a minor effect of freeze-drying on the drug release profile

Amphiphilic and thermosensitive copolymers based on pullulan and Jeffamine®: Synthesis, characterization and physicochemical properties

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Saccharide effect on the LCST property of a polyether: Influence of structure and length

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