Silicalites and Mesoporous Silica Nanoparticles for photodynamic therapy

International audienceThe synthesis of silicalites and Mesoporous Silica Nanoparticles (MSN), which covalently incorporate original water-soluble photosensitizers for PDT applications is described. PDT was performed on MDA-MB-231 breast cancer cells. All the nanoparticles showed significant cell death after irradiation, which was not correlated with 1O2 quantum yield of the nanoparticles. Other parameters are involved and in particular the surface and shape of the nanoparticles which influence the pathway of endocytosis. Functionalization with mannose was necessary to obtain the best results with PDT due to an active endocytosis of mannose-functionalized nanoparticles. The quantity of mannose on the surface should be carefully adjusted as a too high amount of mannose impairs the phototoxicity of the nanoparticles. Fluorescein was also encapsulated in MCM-41 type MSN in order to localize the nanoparticles in the organelles of the cells by confocal microscopy. The MSN were localized in lysosomes after active endocytosis by mannose receptors

Design of One-Dimensional Coordination Networks from a Macrocyclic {3d-4f} Single-Molecule Magnet Precursor Linked by [W(CN)8]3− Anions

The outcome of 1:1 reactions of the tetranuclear 3d-4f Single Molecule Magnet (SMM) [Cu3Tb(LPr)(NO3)2(H2O)]NO3 (1) with (TBA)3[W(CN)8] (TBA = tri-nbutyl ammonium cation, [(n-Bu)3N−H]+) in dimethylformamide (DMF) is dependent on the crystallization method employed: liquid−liquid diffusion of the reagents together gives {[Cu3Tb(LPr)W(CN)8(DMF)4]*(DMF)}n (2) whereas diethyl ether vapor diffusion into the reaction solution gives {[Cu3Tb(LPr)W(CN)8(DMF)3(H2O)3]*(DMF)1.5*(H2O)0.5}n (3). Both compounds are obtained as black single crystals and feature one-dimensional (1D) coordination networks (chains) of [1]3+ macrocycles linked by [W(CN)8]3− anions. The two assemblies differ from a structural point of view...