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Interpenetrating polymer networks (IPNs) have gained great attention for a number of biomedical applications due to their improved properties compared to individual components alone. In this study, we investigated the capacity of newly-developed naturally-derived IPNs as potential biomaterials for tissue engineering. These IPNs combine the biologic properties of a fibrous fibrin network polymerized at the nanoscale and the mechanical stability of polyethylene oxide (PEO). First, we assessed their cytotoxicity in vitro on L929 fibroblasts. We further evaluated their biocompatibility ex vivo with a chick embryo organotypic culture model. Subcutaneous implantations of the matrices were subsequently conducted on nude mice to investigate their biocompatibility in vivo. Our preliminary data highlighted that our biomaterials were non-cytotoxic (viability above 90%). The organotypic culture showed that the IPN matrices induced higher cell adhesion (across all the explanted organ tissues) and migration (skin, intestine) than the control groups, suggesting the advantages of using a biomimetic, yet mechanically-reinforced IPN-based matrix. We observed no major inflammatory response up to 12 weeks post implantation. All together, these data suggest that these fibrin-based IPNs are promising biomaterials for tissue engineering.

Fluorinated polyacrylates are highly hydrophobic and oleophobic. However, their poor mechanical properties prevent their development in many applications. Combination of a fluorinated polyacrylate network with a rigid cellulose acetate butyrate CAB network in an interpenetrating polymer network IPN architecture is an effective method for improving the mechanical properties of fluorinated polyacrylates. IPNs combining poly3,3,4,4,5,5,6,6,7,7,8,8,8tridecafluorooctyl acrylate polyAcRf6 with CAB were prepared according to an in situpolymerizationcrosslinking synthesis. CAB was crosslinked by addition between unmodified hydroxyl groups and the isocyanate of a pluriisocyanate crosslinker. The fluorinated network was obtained through freeradical copolymerization of 3,3,4,4,5,5,6,6,7,7,8,8,8tridecafluorooctyl acrylate with polyethylene glycol dimethacrylate. The rates of formation of both networks were followed using Fourier transform infrared spectroscopy. Differential scanning calorimetry DSC and dynamic mechanical thermal analysis DMTA of IPNs show a single glass transition temperature and a single mechanical relaxation temperature, which are characteristic of a high degree of interpenetration between the partner networks. The mechanical properties of IPNs are greatly improved compared with those of the single fluorinated network. CABpolyAcRf6 IPNs were prepared, and characterized using DSC and DMTA as well as contact angle measurements for their surface properties. As hoped, the mechanical properties of such materials are much improved compared with those of the fluorinated partner alone. Copyright © 2010 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

When a dioctadecyldimethylammonium bromide (DODA) monolayer is spread onto a styrene sulfonate (SSt) aqueous solution, this monomer undergoes a spontaneous polymerization process Fichet, O; Teyssié, D. Macromolecules2002, 35, 5352. However, the polymer synthesized in this monolayer cannot be investigated by classical characterization techniques. Brewster angle microscopy has thus been used as a complementary method in order to study this spontaneous polymerization. From these measurements, the threshold concentration above which the spontaneous polymerization occurs has been determined more precisely; the monomer adsorption under the DODA monolayer has been evidenced as being very fast, as supposed previously; moreover, sodium bicarbonate is confirmed as an inhibitor of the polymerization. Also, the replacement of SSt by toluene sulfonate (TSt) confirms the SSt spontaneous polymerization. Finally, the molecular weight and/or the structure of the polymer synthesized in the monolayer seems to be different from those synthesized in solution. [ABSTRACT FROM AUTHOR]