Bioinspired Polydopamine Coating-Driven Oriented Lamellar Nanocrystalline 3Y-TZP Structures Enhance Cell Bridge Formation for Osteogenic Differentiation via Mechanotransduction.

Abstract

Commercially used 3 mol % yttrium-stabilized tetragonal zirconia polycrystal (3Y-TZP) dental implants encounter clinical challenges, partially due to inadequate surface and structure design for effective osseointegration. Conventional micro- and nanomachining may introduce microcracks that weaken zirconia, and its highly ordered surface does not favor osteogenesis. Herein, we engineered a globally oriented, bone-mimetic anisotropic architecture by coating nanosized 3Y-TZP particles with polydopamine (pDA) and directing their assembly via freeze-casting. The resulting lamellar structures induce mesenchymal stem cell polarization, enhancing the transmission of traction force to the nucleus via the Talin1-FAK-YAP mechanotransduction pathway. Moreover, the molecular clutch model, combined with experimental data, demonstrated that specific lamellar architecture optimally balances focal adhesion anchoring and internal contractility, thereby supporting stable cell bridge formation through cytoskeleton tension. Bridges promote osteogenesis <i>in vitro</i> and osseointegration <i>in vivo via</i> mechanotransduction. These findings establish a structure-first, chemistry-independent manufacturing strategy for zirconia implants favorable for scalable, cost-effective production.