Tuning Pore Sizes of Core-Shell Dendritic Mesoporous Silica Nanoparticles for Efficient Loading of Functional...

Precise control over pore accessibility in dendritic mesoporous silica nanoparticles (DMSNs) is essential for loading and transport of large biomolecules and functional nanoparticles for catalysis, sensing, and further applications. Here, we present a scalable anion-assisted synthesis using sodium salicylate to tune pore size and shell thickness in nano- (170 nm) and microscale (1 μm) DMSNs core-shell particles. By varying the core-to-silane ratio, complex pore structure can be adjusted without altering the surfactant composition. Increasing the relative core content reduces silane availability per particle and suppresses secondary micelle filling, eliminating small mesopores (∼4 nm) while preserving large radially oriented interwrinkle mesopores (12-21 nm), consistent with a micelle-filling growth mechanism. This approach yields shell thicknesses ranging from ∼19 ± 5 nm to 87 ± 7 nm for small cores and from ∼11 ± 17 nm to 151 ± 23 nm for large cores. Loading experiments with silver nanoparticles (∼4 nm) and lysozyme (∼4 nm) reveal that diffusion limitations, rather than total surface area, control uptake in these materials. Core-shell particles dominated by large, accessible interwrinkle mesopores exhibit substantially higher loading than structures containing a higher fraction of small mesopores. Surface-area-normalized lysozyme loading reaches 4.1 ± 1.1 mg m^-2 for large-core (1 μm) particles with predominantly open interwrinkle channels, demonstrating that small mesopores can significantly reduce effective accessibility despite increasing nominal surface area. These results establish the core-to-silane ratio as a simple and robust parameter for engineering hierarchical pore architectures in DMSNs and provide a practical framework for designing mesoporous hosts for enzymes, nanocatalysts, and other nanoscale guests.