Engineering Ga-containing dendritic MFI zeolites as safe-by-design hierarchical and immunomodulatory nanointerfaces

The development of biocompatible and multifunctional inorganic nanomaterials is crucial in nanomedicine, requiring a balance of structural precision, safety, and therapeutic efficacy. In this work, we report the synthesis of nanometric dendritic gallium-containing MFI (d-Ga-MFI) zeolites from zeolite embryos functionalized with an amphiphilic organosilane, engineered as safe and bioactive inorganic interfaces. By systematically optimizing the synthesis, precise control over particle size, morphology, and hierarchical porosity was achieved. The final materials are highly crystalline dendritic zeolites with nanometric particle dimensions (<200 nm), high surface areas and pore volumes, with yields exceeding 90%. Optimization of the xerogel route enabled fine-tuning of gallium content and accessibility, yielding structurally balanced materials (d-Ga-MFI-X2-5) in which gallium is predominantly incorporated in tetrahedral coordination sites with a loading of 4 wt% Ga. In vitro evaluation using RAW 264.7 macrophages demonstrated excellent biocompatibility (cell viabilities above 90% across a wide concentration range), together with a marked attenuation of lipopolysaccharide-induced inflammatory responses, outperforming benchmark mesoporous silica nanoparticles. These results demonstrate that d-Ga-MFI zeolites can uniquely combine structural robustness, interconnected hierarchical porosity, and intrinsic immunomodulatory behavior. Overall, this study establishes d-Ga-MFI zeolites as a safe-by-design inorganic platform with strong potential for advanced biomedical applications.