Trithiocarbonate (macro) RAFt agents for the preparation of polymeric nanomaterials in homogeneous and heterogeneous media

Poster (2007, August 31)

Novel amphiphilic degradable copolymers for drug deivery systems

Poster (2007, August 31)

Macromolecular engineering of aliphatic polyesters based on macrocyclic units

Poster (2007, August 31)

The last decades have witnessed a steadily increasing progress in the macromolecular engineering of the main families of synthetic polymers. Ring-shaped copolymers show a unique topology due to the ... [more ▼]

The last decades have witnessed a steadily increasing progress in the macromolecular engineering of the main families of synthetic polymers. Ring-shaped copolymers show a unique topology due to the absence of any chain-end and exhibit distinct properties from their linear counterparts, such as glass transition temperature, order-disorder transition, reduced viscosity, lower hydrodynamic volumes. This communication aims at reporting on a novel route to biodegradable cyclic polyesters. Our strategy is based on the work of Prof. Kricheldorf who initiated the ring-opening polymerization of ε-caprolactone by cyclic tin dialkoxides, e.g., 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP) in order to obtain “living” macrocyclic PCL, still containing two endocyclic tin-oxygen bonds. In this work, the resumption of polymerization by a few units of ε-caprolactone substituted by an acrylic unit, e.g., 1-(2-oxooxepan-3-yl)ethyl prop-2-enoate, followed by intramolecular photo-cross-linking of pendant unsaturations and finally by hydrolysis gave rise to macrocyclic PCL. As a rule, this strategy is very well-suited for the synthesis of high molecular weight PCL. Moreover, tin alkoxides were kept untouched after the cross-linking step and remained thus available for further macromolecular engineering. The process was extended to the synthesis of other architectures such as sun-shaped, two-tail tadpole-shaped, eight-shaped and symmetrical four-tail eight-shaped copolyesters. [less ▲]

Electrografting method for forming and regulating a strong adherent nanostructured polymer coating

Patent (2007)

Electrografting method for forming and regulating a strongly adherent nanostructured polymer coating onto an electro-conductive surface profile characterized in that the surface profile is regulated by ... [more ▼]

Electrografting method for forming and regulating a strongly adherent nanostructured polymer coating onto an electro-conductive surface profile characterized in that the surface profile is regulated by electrodeposition of nanometre- and/or micrometre-scale nuclei onto the surface profile prior to or simultaneously to the formation of the polymer coating. [less ▲]

PEGylated PLGA-based nanoparticles targeting M cells for oral vaccination

in Journal of Controlled Release (2007), 120(3), 195-204

To improve the efficiency of orally delivered vaccines, PEGylated PLGA-based nanoparticles displaying RGD molecules at their surface were designed to target human M cells. RGD grafting was performed by an ... [more ▼]

To improve the efficiency of orally delivered vaccines, PEGylated PLGA-based nanoparticles displaying RGD molecules at their surface were designed to target human M cells. RGD grafting was performed by an original method called "photografting" which covalently linked RGD peptides mainly on the PEG moiety of the PCL-PEG, included in the formulation. First, three non-targeted formulations with size and zeta potential adapted to M cell uptake and stable in gastro-intestinal fluids, were developed. Their transport by an in vitro model of the human Follicle associated epithelium (co-cultures) was largely increased as compared to mono-cultures (Caco-2 cells). RGD-labelling of nanoparticles significantly increased their transport by co-cultures. due to interactions between the RGD ligand and the I intregrins detected at the apical surface of co-cultures. In vivo studies demonstrated that RGD-labelled nanoparticles particularly concentrated in M cells. Finally, ovalbumin-loaded nanoparticles were orally administrated to mice and induced an IgG response, attesting antigen ability to elicit an immune response after oral delivery. [less ▲]

Synthesis of functional amphiphilic copolymers for the elaboration of third generation drug nanocarriers

Poster (2007, May 24)

Summary of aim and achievements in Work Package 7 "Functional Coatings"

Conference (2007, May 11)

Synthesis of adherent hydrophilic polypyrrole coatings onto (semi)conducting surfaces

in Chemistry of Materials (2007), 19(9), 2364-2371

Hydrophilic and adherent polypyrrole coatings were prepared by a two-step electrochemical method. First, alpha-pyrrole, omega-acrylate polyethylene oxide (Py-PEO-A) dual macromonomer was synthesized by ... [more ▼]

Hydrophilic and adherent polypyrrole coatings were prepared by a two-step electrochemical method. First, alpha-pyrrole, omega-acrylate polyethylene oxide (Py-PEO-A) dual macromonomer was synthesized by anionic polymerization and electrografted onto (semi)conducting substrates by cathodic polymerization of the acrylic end-group. The obtained adherent coating is hydrophilic and thus swells in water and bears a pyrrole ring, a precursor of the conducting polymer. In a second step, the coating is anodically polarized in a mixture of Py and Py-PEO to give the hydrophilic and adherent polypyrrole. Properties such as morphology, adherence, electroactivity, and hydrophilicity of these coatings were investigated by conventional methods and compared to those of pure polypyrrole coatings. These novel coatings exhibit efficient protein adsorption repellency and are thus good candidates for applications in biomaterials and biosensors. [less ▲]

New monomers tailored for direct electrografting onto carbon in water

in Macromolecular Rapid Communications (2007), 28(8), 948-954

Electrografting, which is an electropolymerization technique dedicated to the chemisorption of polyacrylates onto conductive surfaces, was actively studied in anhydrous organic media until now. This ... [more ▼]

Electrografting, which is an electropolymerization technique dedicated to the chemisorption of polyacrylates onto conductive surfaces, was actively studied in anhydrous organic media until now. This communication aims at extending this technique to aqueous media for the grafting of polyacrylates onto carbon. The key criterion for the successful electrografting under these not very demanding experimental conditions (water vs. anhydrous organic solvents) is the use of amphiphilic acrylic monomers. The impact of the chemical structure of these new monomers on the coating properties was investigated. Composition of the coatings was analyzed by FT-IR ATR and XPS, whereas film thickness and morphology were analyzed by ellipsometry and AFM, respectively. [less ▲]

C-60-containing nanostructured polymeric materials with potential biomedical applications

in Polymer (2007), 48(7), 1835-1843

Star-shaped polymers with a fullerene (C-60) Core and an unexpanded structure were successfully prepared by reaction Of C60 with amino end-capped polyesters HxC60(NHPCLn)(x) and polyethers HxC60(NHPEG(n ... [more ▼]

Star-shaped polymers with a fullerene (C-60) Core and an unexpanded structure were successfully prepared by reaction Of C60 with amino end-capped polyesters HxC60(NHPCLn)(x) and polyethers HxC60(NHPEG(n))(x), respectively. Upon irradiation of these C-60-derivatives, a large amount of singlet oxygen was released. Compared to previously synthesized star-shaped azafulleroids with an expanded structure, the photosensitivity of HxC60(NHPCLn)(x) is higher as assessed by a higher production of singlet oxygen. The cytotoxicity of the photoactive water-soluble HxC60(NHPEG(n))(x) derivatives was tested against THP-1 cells and expressed in terms of cell viability. Moreover, they were processed as micro-/nanosized fibers by electrospinning, which however required the addition of poly(F-caprolactone) (PCL). The diameter distribution of the fibers was trimodal, where the fraction with the 270 nm average diameter was the major population. Because of their photoactivity, the herein reported star-shaped C-60-derivatives are promising candidates for photodynamic cancer therapy and treatment of multidrug resistant pathogens. (c) 2007 Elsevier Ltd. All rights reserved. [less ▲]