Ordered mesoporous silica monoliths: synthesis, preparation and potential applications

Colmenares Quevedo, María Gracia
Arruebo Gordo, Manuel (dir.) ; Balas Nieto, Francisco (dir.)

Universidad de Zaragoza, CIEN, 2012
Departamento de Ingeniería Química y Tecnologías del Medio Ambiente, Área de Ingeniería Química

Máster Universitario en Materiales Nanoestructurados para Aplicaciones Nanotecnológicas (Nanostructured Materials for Nanotechnology Applications)

Resumen: The work carried out was focused on the preparation of rigid porous silica monoliths, in order to investigate applications as controlled drug release matrices. All work was based on the hexagonally-ordered mesoporous SBA-15 materials, and monoliths were obtained by gel-casting procedures. SBA-15 powder was successfully synthesized and characterized using SEM and TEM imaging, nitrogen adsorption and small-angle X-ray diffraction. Synthesis yielded fibrous SBA-15 particles with diameters between 4,5 and 7,5µm and lengths between 75 and 105µm, and highly ordered cylindrical pores arranged in a hexagonal fashion with a diameter between 5,6 and 6,9 nm. Functionalization of SBA-15 powder was carried out using (3-Aminopropyl)triethoxysilane as a functionalizing agent, in order to test functionalization effects on drug release, and to prepare more stable monoliths. Monoliths were prepared using gel-casting procedures; a suspension of polyacrylamide precursors and powder SBA-15 was centrifuged in a glass mold, and polymer hardening and further removal of the polymer template yielded stable monoliths exhibiting a bimodal pore structure confirmed by intrusion characterization. Macroscopic dimensions of the monoliths were 3mm in diameter and approximately 6 mm in length, with macropores around 3 µm and the characteristic mesopores of SBA-15. Monoliths were also functionalized using (3-Aminopropyl)triethoxysilane. Drug loading for drug delivery experiments was carried out by placing as-synthesized and functionalized SBA-15 powders and monoliths in direct contact with a solution of a model antibiotic, namely cefuroxime sodium salt. Functionalized powders yielded the highest loads, followed by unmodified powders, modified monoliths and with as-synthesized monoliths exhibiting the lowest loads. Drug release experiments were focused on release of cefuroxime from as-synthesized and amino-functionalized SBA-15 powders and monoliths. Monoliths exhibit an initial burst release that was attributed to antibiotic loaded in the macroporous reservoirs, while a more controlled release was obtained from the powder counterparts.

Tipo de Trabajo Académico: Trabajo Fin de Master