Tailoring Cell Behavior and Antibacterial Properties on Zirconia Biomaterials through Femtosecond Laser-Induced Micropatterns and Nanotopography

This study explores the potential of ultrashort pulsed-direct laser interference patterning (USP-DLIP) to fabricate micropatterns on zirconia surfaces, aimed at enhancing their cell-instructive and antibacterial properties for biomedical applications. A femtosecond laser was employed to fabricate 3 and 10 μm periodic linear (L3 and L10) and grid (G3 and G10) patterns on tetragonal zirconia polycrystal stabilized with 3% molar yttrium oxide (3Y-TZP). The patterns exhibited homogeneous, high-aspect-ratio structures with laser-induced nanotopography within the grooves while maintaining minimal surface damage. All patterns significantly enhanced human mesenchymal stem cell (hMSCs) adhesion, spreading, and migration through topographical guidance and nanotopography-induced cell anchoring. Pattern geometry influenced cell morphology and migration: linear patterns induced high elongation and alignment along the grooves, leading to unidirectional migration, while grid structures promoted widespread cells with bidirectional alignment, promoting bidirectional migration. Antibacterial assessment using Pseudomonas aeruginosa (P. aeruginosa) (Gram-negative) and Staphylococcus aureus (S. aureus) (Gram-positive) revealed a size-dependent bacterial response. The patterns of lower periodicity (L3 and G3) showed superior antibacterial properties, reducing bacterial colonization through distinct mechanisms: mechanical trapping for P. aeruginosa (25% reduction) and disruption of bacterial aggregation for S. aureus (30% reduction). Coculture experiments with hMSCs and bacteria confirmed that L3 and G3 surfaces effectively combined enhanced cell adhesion with reduced bacterial colonization, highlighting the potential of USP-DLIP for developing multifunctional cell-instructive and antibacterial biomaterial surfaces.