pH Stimuli Responsive Dextran Gated Mesoporous Silica as a Viable Delivery Vehicle

Mesoporous materials hold immense potential due to their diverse applications (catalysis, separation, drug delivery, etc.) viability. To unlock this potential, controlling the transport of molecules within their nanochannels is crucial. This study explores a novel technique to manipulate pore properties by hetero-functionalizing mesoporous silica with carboxylic acid and propylamine groups, creating pH-responsive surfaces. The negatively charged surface at basic pH attracts and loads a cationic dye through electrostatic interactions. This cargo can be efficiently released by switching to acidic pH, reversing the surface charge. Furthermore, the system incorporates dextran as a "gatekeeper" for controlled release. The study demonstrates significant differences in release profiles between functionalized materials, highlighting the effectiveness of this approach. Notably, the functionalization method strategy using 1,4-dioxane and appropriate reaction timing enables the desired properties for the first time. This work paves the way for designing advanced mesoporous materials with tailored functionalities for various applications.