Ph- Responsive Dextran Gated Functionized Mesoporous Silica for Drug Delivery

Yusuf, Olatunji Waidi (2019-07-12)


Mesoporous materials have generated a lot of interest over the past few decades owing to their wide range of applications in catalysis, separation, drug delivery, sensors, adsorption, photonics, nanodevices etc. To realise such applications, it is necessary to regulate the transport of molecules through the mesochannels which resulted in a surge of interest to manipulate the pore size, surface charge and philicity. The current work presents the results of an experimental study of a technique whereby synthesized mesoporous silica were hetero-functionalized with carboxylic acid and propylamine functional groups in certain proportions giving rise to pH- dependent charge reversal surfaces. A cationic dye (cargo) was loaded into the mesoporous silica at basic pH utilizing the electrostatic attractions between dye molecules and anionic surfaces. The loaded cargo could be quantitatively released by decreasing the pH to the acidic range. Further, by employing dextran as a pore gating system, we were able to demonstrate an efficient system of cargo release system. There was a huge difference between the release at pH for both Mesoporous silica spheres functionalized with amine and succinic anhydride (MCM-Z) and Mesoporous silica spheres functionalized with amine and succinic anhydride Dextran capped (MCM-ZD). But for MCM-Z, the release at pH 5 was higher than that of MCM-ZD as expected. The % weight release of both room temperature and temperature controlled in vitro environments were similar. For the first time, we were able to functionalize a mesoporous nano silica with succinic anhydride using 1,4-dioxane as solvent in a particular way to have such unique properties for the required application.