Guilhem Godeau

Azidomethyl-EDOT as a Platform for Tunable Surfaces with Nanostructures and Superhydrophobic Properties

We report for the first time the use of click chemistry both to modify the surface morphology and to obtain superhydrophobic properties. Using click chemistry as a postfunctionalization of poly(3,4-ethylenedioxythiophene) nanofibers bearing azido groups, we show that the nanostructures already present on the surface as well as the surface hydrophobicity are highly affected by the used alkyne. These results allow one to envisage widely varied strategies to modify nanostructured surfaces while introducing various functions, for example to produce biosensors or antibacterial surfaces.

Staudinger Vilarassa reaction: A powerful tool for surface modification and superhydrophobic properties

Here we report for the time, the use of Staudinger-Vilarrasa reaction for fast surface functionalization. Using poly(3,4-ethylenedioxythiophene) nanofibrous surfaces bearing azido groups, this reaction allows for the functionalization of surfaces with amide linker in just 3 h. The functionalization by long alkyl chains induces the formation of highly hydrophobic surfaces while the surface structures are preserved. This reaction can be a key pathway for fast surface modification for a large range of applications such as in cell or bacterial adhesion, for example.

A template-free approach to nanotube-decorated polymer surfaces using 3,4-phenylenedioxythiophene (PhEDOT) monomers

In this work, novel 3,4-phenylenedioxythiophene (PhEDOT) monomers with alkyl, branched, and aromatic substituents were synthesized and tested for their efficacy at forming surfaces with unique wetting properties and surface morphology without the aid of surfactants. Monomers with a naphthalene substituent clearly showed the highest capacity to stabilize gas bubbles (O2 or H2) formed in solution during electrodeposition from trace water, resulting in the formation of nanotubes. Variation in the resulting density, diameter, and height of nanotubes was demonstrated by varying the electropolymerization protocol, conditions, or electrolyte used. The wetting induced by the nanotube formation results in the surfaces formed having both high contact angles with water (θW) and strong adhesion, despite all polymers being intrinsically hydrophilic. This one-step and easily tunable approach to nanotube formation has potential to advance applications in membrane design, water transport and harvesting, as well as sensor design.

Amphiphilic Copolymer for Delivery of Xenobiotics: In Vivo Studies in a Freshwater Invertebrate, a Mesostominae Flatworm

The synthesis of an amphiphilic polymethacrylate copolymer containing cholesterol hydrophobic moieties and rhodamine as a fluorescent probe, the formation of microspheres, and the uptake of these microspheres in an invertebrate are reported. The cholesterol-derived methacryloyl monomer, which was prepared via a one-step synthesis, was copolymerized with methacrylic acid and methacryloxyethyl thiocarbamoyl rhodamine B in the presence of AIBN as initiator. The obtained dye-labeled copolymer was characterized by (1)H NMR and UV-vis spectroscopy. Fluorescence and TEM microscopies studies show that this amphiphilic copolymer aggregates to give microspheres with diameters ranging from approximately 3 to 11 microm. The in vivo study in a freshwater invertebrate, a Mesostominae flatworm (Rhabdocoela, Thyphloplanidae), indicates that the microspheres enter the cells by endocytosis. The data collected demonstrate that the rhodamine B covalently attached to the amphiphilic copolymers is bioaccumulated without being translocated out of the cell by the multixenobiotic resistance (MXR) transporters. As the MXR system is similar to the multidrug resistance (MDR) first observed in tumor cell lines resistant to anticancer drugs, the present data confirm the significant role that amphiphilic copolymers can play in the ongoing development of drug delivery strategies to overcome multidrug resistance. These investigations illustrate a promising approach for the development of new medical and ecotoxicological tools that can deliver specific molecules within cells.

Ante versus post-functionalization to control surface structures with superhydrophobic and superoleophobic properties

Here, we report the first use of the Staudinger–Vilarrasa reaction with perfluorinated surface modification. Based on a 3,4-ethylenedioxythiophene (EDOT) monomer bearing azido groups, we develop ante and post deposition strategies in order to prepare functionalized surfaces. The Staudinger–Vilarrasa reaction allows the reduction of the azido groups into amine functions and the reaction with carboxylic acids leads to amide bounds. Here, the surfaces are investigated for their morphologies and surface properties depending on the side chain length and the modification strategy. This work shows that various wettability properties from hydrophobic to superhydrophobic or oleophilic to superoleophobic can be obtained depending on both the modification strategy and nature of the side chain.

Switchable Surface Wettability by Using Boronic Ester Chemistry.

Here, we report for the first time the use of a boronic ester as an efficient tool for reversible surface post-functionalization. The boronic ester bond allows surfaces to be reversibly switched from hydrophilic to hydrophobic. Based on the well-known boronic acid/glycol affinity, this strategy offers the opportunity to play with surface hydrophobic properties by adding various boronic acids onto substrates bearing glycol groups. The post-functionalization can then be reversed to regenerate the starting glycol surface. This pathway allows for the preparation of various switchable surfaces for a large range of applications in biosensors, liquid transportation, and separation membranes.

Superhydrophobic/highly oleophobic surfaces based on poly(3,4-propylenedioxythiophene) surface post -functionalization

Here, we report for the first time the use of poly(3,4-propylenedioxythiophene) as platform for surface post-functionalization using the Staudinger-Vilarrasa reaction in order to covalently link perfluorinated chains and obtain various hydrophobic/oleophobic properties. 3,4-propylenedioxythiophene with one or two azido groups are prepared, in order to determine the impact of the number of functional groups on the surface morphology and wettability. Here, we show the possibility to prepare parahydrophobic (high water adhesion) or superhydrophobic (low water adhesion) surfaces with highly oleophilic to highly oleophobic properties.

Formulation of Highly Functionalizable DNA Nanoparticles Based on 1,2‐Dithiolane Derivatives

We describe the formulation of synthetic virus models based on ionic compounds bearing the polymerizable 1,2‐dithiolane moiety. First, cationic amphiphiles containing the polymeric inducer were prepared and used to efficiently condense a DNA plasmid (pDNA) into a highly monodisperse population of small polymeric cationic DNA nanoparticles (NPs; Dh∼100 nm). These nonspecific cationic particles were then functionalized with anionic PEGylated conjugates, also based on the 1,2‐dithiolane motifs, in order to produce stable and fully dispersible stealth DNA nanoparticles. Our results show that both ionic interactions and polymerization based on the 1,2‐dithiolane pattern occur and that they produce highly functionalizable nonviral DNA NPs.

pH-Driven Wetting Switchability of Electrodeposited Superhydrophobic Copolymers of Pyrene Bearing Acid Functions and Fluorinated Chains

A smart stimuli-responsive surface was fabricated by the electro-copolymerization of pyrene monomers followed by base and acid treatment. Copolymers of pyrenes bearing fluorinated chains (Py-nF6 ) and acid functions (Py-COOH) were produced with different molar concentrations of each monomer (0, 25, 50, 75, and 100 % of Py-nF6 vs. Py-COOH) by an electrochemical process. Two different perfluorinated pyrenes containing ester and amide groups were used to reach superhydrophobic properties. The relation of those bonds with the final properties of the surface was explored. The pH-sensitive group of Py-COOH allowed the surfaces to be reversibly switched from superhydrophobic (water contact angle>θw >150° and very low hysteresis) to hydrophilic (θw <90°). The amide and ester bonds influenced the recovery of the original wettability after both base and acid treatment. Although the fluorinated homopolymer with ester bonds was insensitive to base and acid treatment due to its superhydrophobic properties with ultralow water adhesion, the recovery of the original wettability for the copolymers was much more important with amide bonds due to the amide functional groups be more resistant to the hydrolysis reaction. This strategy offered the opportunity to access superhydrophobic films with switchable wettability by simple pH treatment. The films proved to be a good tool for use in biological applications, for example, as a bacterial-resistant film if superhydrophobic and as a bacterial-adherent film if hydrophilic.

In Vivo Characterization of Dynein-Driven nanovectors Using Drosophila Oocytes

Molecular motors transport various cargoes including vesicles, proteins and mRNAs, to distinct intracellular compartments. A significant challenge in the field of nanotechnology is to improve drug nuclear delivery by engineering nanocarriers transported by cytoskeletal motors. However, suitable in vivo models to assay transport and delivery efficiency remain very limited. Here, we develop a fast and genetically tractable assay to test the efficiency and dynamics of fluospheres (FS) using microinjection into Drosophila oocytes coupled with time-lapse microscopy. We designed dynein motor driven FS using a collection of dynein light chain 8 (LC8) peptide binding motifs as molecular linkers and characterized in real time the efficiency of the FS movement according to its linker’s sequence. Results show that the conserved LC8 binding motif allows fast perinuclear nanoparticles accumulation in a microtubule and dynein dependent mechanism. These data reveal the Drosophila oocyte as a new valuable tool for the design of motor driven nanovectors.