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 <i>Pseudomonas aeruginosa</i> (<i>P. aeruginosa</i>) (Gram-negative) and <i>Staphylococcus aureus</i> (<i>S. aureus</i>) (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 <i>P. aeruginosa</i> (25% reduction) and disruption of bacterial aggregation for <i>S. aureus</i> (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.