Nanoparticles and hydrogels for the photochemical delivery of nitric oxide

Abstract

The incorporation of nitric oxide (NO) donor molecules in nontoxic vehicles allows the topical or localized delivery of free NO for therapeutic purposes. In the case of photosensitive NO donors, the rate of NO release can be greatly increased under irradiation, leading to a potentiation of the NO actions. Hydrogels and nanoparticles comprise two potential vehicles for the controlled release of NO, since both can be charged or functionalized with NO-releasing moieties and allow topical and localized applications. In this project, three platforms for the photochemical release of NO will be prepared and characterized: 1) Pluronic F-127 hydrogels, charged with S-nitrosoglutathione (GSNO) and 5-chloro-2-nitrobenzotrifluoride (NBF) and, 2) NBF-modified silica nanoparticles and 3) NDF-modified core-shell silica-coated Fe3O4 nanoparticles. F-127 hydrogels will be prepared by the cold method and characterized thermally and spectroscopically. NO-releasing silica nanoparticles will be prepared by the hydrolysis and condensation of 3-aminopropyltrimethoxysilane (APTES) modified with NBF (APTES-NO), based on the Stöber method, and characterized by light scattering and transmission electron microscopy. Core-shell nanoparticles of magnetite (Fe3O4-NP) coated with silica functionalized with APTES-NO, will be prepared using the Layer-by-Layer assembly technique through the previous coating of Fe3O4-NPs with poly(diallyldimethylammonium chloride), followed by a coating of poly(sodium 4-styrenesulfonate), and APTES-NO functionalization. Formulations from these three platforms will be characterized regarding their photochemical NO-releasing properties under irradiation with visible light, using amperometric and chemiluminescence techniques for measuring real time NO-release. The three platforms will be compared for evaluating their potential uses for the controlled release of NO in topical applications.