title: Anisotropic magnetic porous assemblies of oxide nanoparticles interconnected via silica bridges for catalytic application.
abstract: We report the microfluidic chip-based assembly of colloidal silanol-functionalized silica nanoparticles using monodisperse water-in-oil droplets as templates. The nanoparticles are linked via silica bridges, thereby forming superstructures that range from doublets to porous spherical or rod-like micro-objects. Adding magnetite nanoparticles to the colloid generates micro-objects that can be magnetically manipulated. We functionalized such magnetic porous assemblies with horseradish peroxidase and demonstrate the catalytic binding of fluorescent dye-labeled tyramide over the complete effective surface of the superstructure. Such nanoparticle assemblies permit easy manipulation and recovery after a heterogeneous catalytic process while providing a large surface similar to that of the individual nanoparticles.
authors.affiliation: Laboratory of Microsystems, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Josias B
authors.initials: JB
authors.lastname: Wacker
authors.forename: Virendra K
authors.initials: VK
authors.lastname: Parashar
authors.forename: Martin A M
authors.initials: MA
authors.lastname: Gijs