Beyond diameters: Decoding fabrication patterns of hierarchical micro-nano titanium implants via anodization and their geometries on region-specific soft-tissue integration

Abstract

Electrochemical anodization creates titania nanopores (TNPs) on Ti implants with distinctive micro-nano geometries to enhance their surface bioactivity, showing the potential to improve soft-tissue integration at varied transmucosal regions. However, understanding how topography regulates TNP dimensions under voltage, and the clinical feasibility of diverse TNP geometries was limited. More crucially, existing research predominantly focused on nanopore diameter, neglecting other geometric characteristics (alignment, texture/roughness) on soft-tissue cells that impeded optimized TNPs design for ideal soft-tissue integration. This study showed nanopore dimensions were voltage-dependent on micro-patterned Ti but remain stable on smooth counterparts. Varied TNPs with similar diameters but different alignment/roughness were selected and identified with similar chemistry/hydrophilicity, but their protein adhesion and stability were length-dependent, showing their feasibility as implant devices. Finally, human gingival fibroblasts (HGFs) and HaCaT epithelial cells functions on varied selected TNPs reflected that nanopores inherently promoted cell responses, but hybrid microgroove-nanopores dramatically enhanced HGF’s collagen and fibronectin secretion, while irregular textured nanopores significantly improved HaCaT adhesion. By addressing the gaps in understanding topographical regulation and the influence of overlooked geometric features beyond diameter, this work advances spatially optimized implant designs for improved epithelial sealing and connective tissue integration at different transmucosal zones for improved implant health.