Nanoreservoir operated by ferrocenyl linker oxidation with molecular oxygen

The fabrication and efficient operation of a redox-driven hybrid nanoreservoir that contains the host-guest pair beta-cyclodextrin (beta-CD) and a ferrocenyl (-Fc) group attached to MCM-41 nanoparticles loaded with rhodamine B are reported. The operation process is based on the effects of pH that is related to the acid catalyzed oxidation of the ferrocenyl group by molecular oxygen (O-2). By a thorough set of experiments, the combined effects of pH and oxygen are exploited to control the releasing process. Such experiments characterize the nanoreservoir at various points along the pathway, and show the level of control achieved over the release of rhodamine B. The results show that the same system can operate under different conditions, i.e., at high O-2 levels and pH close to the physiological one, where the drug-like molecules could be rapidly released, or at low O-2 levels and slightly acidic conditions (pH 5.5 and 6.5), where the drug will be slowly released. In essence, the work presented herein is a step forward in terms of redox-triggered release drug-like molecules from MCM-41.