Xibo Yan

Heptyl mannoside based polymers and nanocapsules : Towards potent anti-adhesive glycomaterials and nanocarriers: Ce travail de thèse est consacré à la préparation de glycopolymères porteurs de groupements pendants mannoside d’heptyle et à l’évaluation de la capacité de ces ligands multivalents à inhiber la fixation bactérienne sur les cellules humaines. Nous avons synthétisé, par polymérisation radicalaire contrôlée, une série de glycopolymères linéaires ou en étoile présentant des masses molaires, des densités en mannoside et des microstructures modulables dans le but d’évaluer l’influence de ces paramètres sur les processus d’interactions avec diverses souches de bactéries E coli (AIEC LF82 et UTI 89). Nous avons tout d’abord mis en évidence par diffusion dynamique et statique de la lumière, la formation d’agrégats entre ces glycopolymères et FimH, la lectine à l’origine de la fixation de souches de bactéries E coli, traduisant des interactions fortes entre les motifs mannosides et les sites de reconnaissance au mannose de la lectine. Nous avons ensuite évalué l’aptitude de ces ligands multivalents à bloquer l’adhésion bactérienne d’AIEC LF82 (impliquée dans la maladie de Crohn) sur des cellules épithéliales intestinales T84. Il a été démontré en conditions in vitro que l’ajout de 10 nM ou 100 nM d’unités mannoside (respectivement en pré- ou post-incubation) réduit de moitié l’adhésion des bactéries sur les cellules épithéliales. L’effet anti-adhésif de ces glycopolymères a été confirmé par des tests ex vivo réalisés sur des intestins isolés de souris transgéniques CEABAC10. Enfin, nous avons exploité la technique de nanoprécipitation pour l’élaboration de nanocapsules de glycopolymères à cœur huileux. Le procédé développé permet la synthèse de nanocapsules de dimensions contrôlées, porteuses de groupements fonctionnels (fluorophores, ligands) ou de particules métalliques et l’encapsulation de molécules actives à cœur en une seule étape.

Chemical gradient‐steered directed transportation is crucial for biological systems. Inspired by nature, self‐propelled artificial nanomotors capable of spontaneously creating chemical gradients via catalytic reactions have been developed for application in physiological environments. Herein, we demonstrate the autonomous movement of lipase‐activated acylated dextran‐fueled nanomotors driven by self‐generated chemical gradients of different compositions in an ion‐enriched aqueous medium. Interfacial hydrolysis degrades the acylated dextran and releases water‐soluble carboxylates into the surrounding media. The motilities of nanomotors containing different acylates exhibit an anti‐carboxylate concentration series, in which fast enzymatic hydrolysis leads to slow self‐propulsion. The study demonstrates that the nature of the product quantitatively governs the dynamic retention of partial carboxylates at the interface. This occurs via interfacial interactions with nanomotors, resulting in interfacial concentration gradients of carboxylates that drive autonomous movement rather than concentration gradients of the produced whole carboxylates. Regulating the compositions of this interfacial chemical field enables the convenient manipulation and modulation of self‐propulsion. This is also applied to widely used urease‐powered nanomotors that generate interfacial chemical gradients with different compositions in response to various pH. Precisely controlling self‐generated interfacial chemical gradients holds considerable potential for developing smart nanobots that can reconfigure self‐propulsion with good adaptability to the surrounding environment.

Chemically powered colloidal motors are self‐propelled tiny machines capable of converting chemical energy into mechanical work or kinetic energy. A wide variety of organic or inorganic substrates are selectively utilized as consumable fuels that would allow the creation of a gradient of chemical concentration via catalytic reactions for driving controllable transport in various complex liquid environments, unlocking the potential of chemically powered colloidal motors in a large range of applications. Recently, combinations of synthetic chemistry and nanotechnology have been exploited to design and construct degradable polymer‐fueled artificial colloidal motors whose chemically powered propulsion relies on a rapid degradation of stimuli‐responsive polymers with labile units in the nanostructured smart colloidal systems under the activation of various physical or chemical stimuli. This review highlights the most recent advances in artificial colloidal motors powered by degradable polymer fuels. It explores the general fabrication approaches to degradable polymer‐fueled colloidal motors with asymmetric morphologies and the powering mechanisms of physical or chemical stimuli‐responsive polymer degradation toward the self‐propelled motion in liquid media and biological microenvironments. The distinct application performance of degradable polymer‐fueled colloidal motors developed so far is reviewed. A future perspective on the development of degradable polymer‐fueled colloidal motors is also proposed.

Poly(vinyl alcohol)s (PVAs) are very popular dispersants for the construction of colloids and common shell-constituents of microcapsules but remain mostly unexplored as building blocks for the design of nanocapsules through nanoprecipitation or other processes. Herein, we first show that model commercial PVAs and oils can be concomitantly engaged in solvent-shifting procedures to give rise to oil-filled nanocapsules in one step. Next, we report the synthesis of precisely defined water-soluble glyco-PVAs by reversible addition-fragmentation chain transfer (RAFT) copolymerization of 6-O-vinyladipoyl-d-glucopyranose and vinyl chloroacetate and selective alcoholysis reactions. We finally demonstrate that these glycopolymers are excellent candidates for the straightforward conception of oil- and drug-filled, surface- and/or core-tagged, stealth, and degradable nanocapsules by nanoprecipitation.

This minireview presents the recent progress on organic nanomotors using stimulus-responsive organic fuels/engines as organic kinetic systems.

Engineered nanoparticles have emerged as new types of materials for a wide range of applications from therapeutics to energy. Still, fabricating nanomaterials presenting complex inner morphologies and shapes in a simple manner remains a great challenge. Herein, we report the template‐free one‐pot continuous gradient nanoprecipitation of different types of non‐compatible polymers to spontaneously form nanostructured particles. The continuous addition of antisolvent induces precipitation and (re)organization of polymer chains at the forming particle interface, ultimately and naturally developing complex inner morphologies and shapes while particle grows. This low‐energy‐cost bottom‐up assembly approach applies to various functional polymers, possibly embedded with metal nanoparticles, for continuous growth into well‐organized nanoparticles. UV crosslinking of the particles and core removal allows both confirming the building process and leading to hollow or multivoid nanomaterials.