Protein-repellent superhydrophobic aluminum mesh biointerfaces direct topography-guided neural stem cell spheroid...

Controlling biointerfacial interactions is a fundamental challenge in three-dimensional (3D) cell culture, where the balance between cell-substrate adhesion and cell-cell cohesion dictates the formation of multicellular constructs. Here, we rationally engineered a superhydrophobic, protein-repellent aluminum mesh via hierarchical structuring and heptadecafluoro-1,1,2,2-tetrahydrodecyl trichlorosilane (HDFS) functionalization to direct topography-guided neural stem cell (NSC) assembly. Physicochemical characterization demonstrated a highly stable non-wetting interface with a static water contact angle of 151.5 ° ± 1.4 °, retaining its superhydrophobic state even after rigorous ethanol sterilization. Crucially, the functionalized interface significantly suppressed protein adsorption, thereby establishing a low-fouling environment that minimizes integrin-mediated non-specific cell adhesion. Time-resolved microparticle tracking elucidated that the synergistic interplay between the low-surface-energy plastron layer and the open mesh microtopography channels physical redistribution away from exposed solid phases toward mesh-defined liquid domains. When applied as an in vitro biointerface, these interfacial physical cues orchestrated the spontaneous aggregation of mouse NSCs into compact, spatially confined 3D spheroids with high viability and preserved stemness. Transcriptomic profiling further confirmed that the topography-guided 3D assembly on our biointerface induced robust microenvironmental adaptations, evidenced by downregulated ribosome biogenesis and upregulated hypoxia/glycolysis and neural-function-associated pathways. This study demonstrates that engineering the physical and chemical wettability parameters of metallic mesh biointerfaces provides a robust, scalable strategy for precisely regulating multicellular 3D architecture and directing cellular fate.