With the advancement of drug delivery system based on mesoporous silica nanoparticles (MSNs), a simple and efficient method regulating the drug release kinetics is needed. We developed redox-responsive release systems with three levels of hindrance around the disulfide bond. Model drug (rhodamine B dye) was loaded into MSNs mesoporous voids and the leakage was prevented by capping the pore opening with β-cyclodextrin. In absence of reducing agent the systems exhibited little leakage, while the addition of dithiothreitol cleaved the disulfide bonds and enabled the release of the cargo. The release rate and amount of the released dye were tuned by the level of hindrance around disulfide bonds, with the increased hindrance causing a decrease in the release rate as well as in the amount of released drug. Thus, we demonstrated the ability of the present mesoporous systems to intrinsically control the release rate and the amount of the cargo by only minor structural variations. Furthermore, an in vivo experiment on the zebrafish confirmed biocompatibility of this model delivery system.
Fe70Pd30 system possesses magnetic shape memory-effect, which can be used in medicine purposes for triggering the drugs, for example. We report on successful direct electrochemical synthesis of Fe70Pd30 nanotubes. The tubes are ferromagnetic with high Ms=170 emu/g. For the application in medicine, the nanotubes were functionalized with the model drug paracetamol. The proposed type of release, with an initial burst and a slower release of the remaining drug, could be suitable for applications where a fast action is required, which then has to be maintained for a certain time period.
COBISS.SI-ID: 25576999
To elucidate the importance of the capping agent size in stimulus-induced release systems from mesoporous silica nanoparticles (MSNs), the effectiveness of poly(propylene imine) dendrimers to control the model drug release was studied. MCM-41-type MSNs were synthesized and characterized. Fluorescent compounds (fluorescein disodium salt and carboxyfluorescein) were loaded in the porous structure of the MSNs and entrapped in the silica matrix with the dendrimers of generations I through V 10 by anchoring dendrimers on the MSNs surface through disulfide bonds. Stimulus-induced release of the cargo was studied in the presence of dithiothreitol (DTT). Dendrimers of generation I and II were found to be more effective in model drug retention and subsequent release than higher generations. Moreover, MSNs modified with larger amounts of dendrimer lowered the cargo release in the presence of DTT. These findings are of importance for optimizing drug delivery systems based on responsive MSNs as they 15 enable tuning of the amount of the released cargo by choosing the capping agent of the appropriate size.