Advanced internally bridged silica core-shell nanocarriers: Design and applications.

Nanomaterial-based delivery systems have gained significant attention for their ability to provide high surface area, tunable porosity, and tailored surface chemistry, key features that enable efficient adsorption and controlled release of active agents. These advanced platforms offer versatile solutions for applications ranging from therapeutic delivery to environmental remediation, by improving loading capacity, release kinetics, and functional performance. Here we tailor a novel core-shell silica nanomaterial with a large complex internal structure in the core and shell, while silica surfaces are bridged by an organic crosslinker in the shell. Firstly, the organo-silica bridging agent (bivalent organic crosslinkers) DABCO-S was prepared through a simple nucleophilic substitution reaction between 3-chloropropyl-triethoxysilane and a strong base bivalent 1,4-diazabicyclo[2.2.2]octane (DABCO). Secondly, dendritic fibrous nanostructured silica (DFNS) was synthesized as the core nanostructure. Thirdly, DABCO-S bridges were integrated into the DFNS morphology surrounding the DFNS core under open-vessel reflux conditions. The resulting core-shell product, incorporating the DABCO-S bridges within the silica shell network around DFNS, is referred to as the DDC structure. This design was strategically chosen based on the hypothesis that such colloidal systems would serve as highly efficient adsorbents for sparsely soluble drug compounds. The pH-responsive DDC colloidal hybrid carriers were evaluated as biocompatible carriers for controlled doxorubicin (DOX) delivery. The results demonstrated that cancer cells exhibited lower viability when treated with DOX-loaded DDC colloidal hybrid carriers compared to free DOX or control groups, indicating an enhanced anticancer effect of the loaded carrier. The high drug loading capacity, encapsulation efficiency, and pH-responsive behavior of these colloidal hybrid carriers in varying cellular environments confirm their suitability as promising candidates for further studies. Future research could focus on incorporating targeting functionalities to enhance their potential as active drug delivery systems.