François Stoffelbach

Light Induced Functionalization of PCL-PEG Block Copolymers for the Covalent Immobilization of Biomolecules

Functionalized poly-epsilon-caprolactone-block-polyethyleneglycol (PCL-PEG) amphiphilic copolymers were prepared to be constituents of nanocarriers used for the targeting of specific cells. Hence, we conceived a smooth and simple photografting methodology on these copolymers using a bifunctional molecular clip (O-succinimidyl-4-(p-azido-phenyl)butanoate). We prepared PCL-PEGs with pendent N-hydroxysuccinimide esters and studied the grafting with 3H-lysine, which radioactivity was counted by LSC. Several parameters were investigated, such as behavior of homopolymers, initial concentrations, irradiation, and incubation durations. Evidences of a PEG directed photografting are discussed and this selectivity could be improved by a selective solvent technique. The photografting on different PCL-PEGs revealed a dependency of the rates to the crystallinity of the copolymers. Several controls by SEC, DLS, and TEM of the treated copolymers were realized. Lastly, the coupling of alpha-D-mannopyranoside ligand was performed, reaching amounts of 5400 nmol/g of PCL-PEG. This derivatized PCL-PEG enters in the preparation of nanocarriers used for the targeting of antigen presenting cells.

Synthesis and deposition of water-dispersed Prussian blue nanocrystals on polymers and CNTs

Nanoparticles can be used for decoration and functionalization of single polymer molecules that have been adsorbed to a solid substrate. Initial attempts to prepare Prussian Blue nanoclusters by a layer-by-layer deposition technique of hexacyanoferrate anions and ferric cations onto isolated polycation chains in water failed because of the desorption of the first layer upon deposition of the next one. A simple method for the preparation of charge-stabilized Prussian Blue nanoparticles of readily adjustable size is reported. Prussian Blue nanoparticles have been purified by addition of non-solvents and redispersed in water without aggregation. Thus formed Prussian Blue nanoparticles are crystalline and display a long-range ferromagnetic ordering at 5.1 K. Prussian Blue nanoparticles were selectively deposited along single polycation molecules to form a one-dimensional array or were attached to the surface of carbon nanotubes (CNTs) functionalized with poly2-vinylpyridine (P2VP). These nanoparticle-based nano-structures might be useful materials for manufacture of electrooptical devices, or mechanically robust ion-sieving membranes.