ABSTRACT
Cellulose-based hydrogels, obtained by tuned, low-cost synthetic routes, are proposed as convenient gel electrolyte membranes. Hydrogels have been prepared from different types of cellulose by optimized solubilization and crosslinking steps. The obtained gel membranes have been characterized by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mechanical tests in order to investigate the crosslinking occurrence and modifications of cellulose resulting from the synthetic process, morphology of the hydrogels, their thermal stability, and viscoelastic-extensional properties, respectively. Hydrogels liquid uptake capability and ionic conductivity, derived from absorption of aqueous electrolytic solutions, have been evaluated, to assess the successful applicability of the proposed membranes as gel electrolytes for electrochemical devices. To this purpose, the redox behavior of electroactive species entrapped into the hydrogels has been investigated by cyclic voltammetry tests, revealing very high reversibility and ion diffusivity.
ABSTRACT
In the present work, we report the synthesis of the novel esters of indomethacin (IDMC) and an ester of reduced IDMC. For this purpose, IDMC is covalently bound by using a spacer chain to the pyrrole (Py) in the 3-position. The innovative pyrrole-indomethacin (3-Py-IDMC) derivates show no cytotoxic effects in primary calvarial osteoblasts. The designed IDMC derivates have been studied because they could be injected locally as a component of polymeric micro-particles. In fact, the new 3-Py-IDMC derivatives will assure their further polymerization since the 2- and 5-monomer positions are free.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/chemical synthesis , Delayed-Action Preparations/chemical synthesis , Indomethacin/chemistry , Pyrroles/chemistry , Actins/chemistry , Animals , Animals, Newborn , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Cell Proliferation/drug effects , Cell Survival/drug effects , Delayed-Action Preparations/pharmacology , Esters , Histocytochemistry , Injections, Intra-Articular , Male , Mice , Osteoblasts/cytology , Osteoblasts/drug effects , Oxidation-Reduction , Primary Cell Culture , Rats , Rats, Sprague-Dawley , Skull/cytology , Skull/drug effectsABSTRACT
Polypyrrole-polysaccharide thin films were electropolymerized from starting solutions containing pyrrole and a polysaccharide, namely, heparin, chondroitin-4-sulphate or hyaluronic acid. The synthesized samples showed good chemical and physicochemical properties determined by the synthesis parameters such as the current density and time. For instance, the sample morphology was strictly correlated to the current density as follows: a smooth surface morphology was observed when the current density was in the range of 100-700 microA/cm(2), whereas high current (I > 1.0 mA/cm(2)) or longer time (synthesis charge > 100 mC/cm(2)) led to rough surfaces. The presence of polysaccharide within the polymeric matrix assured proper hydrophilicity to the samples. The optimized surface chemistry due to the presence of a polysaccharide and the controllable morphology allowed positive cell/substrate interactions and these are proved by cellular tests using MC3T3-E1 osteoblast cultures.
