Bioimplant-on-a-Chip for Facile Investigation of Periodontal Ligament Formation on Biogenic Hydroxyapatite/Ti6Al4 V Implants

Abstract

Highly osseointegrative dental implants surrounded by reconstructed periodontal tissues represent a promising strategy for functional tooth replacement, as they mimic the structural and physiological characteristics of natural teeth. However, there is currently a lack of in vitro platforms that can effectively evaluate the integration of engineered periodontal ligament (PDL) tissues with bioimplants. In this study, we developed a bioimplant-on-a-chip (BoC) platform designed to recapitulate the native PDL-cementum interface and assess the early stage biological performance of bioimplants in vitro. The BoC consists of a dental implant, a calcium phosphate cement (CPC) insert, a nanopatterned polydimethylsiloxane (PDMS) substrate, and PDL-like tissue derived from human dental pulp stem cells (DPSCs). To establish viable culture conditions within the platform, surface coatings and cell seeding densities were optimized to support the formation of PDL-like tissue. Nanogrooved substrates were incorporated to guide cellular alignment, which was assessed through orientation analysis. Collagen fiber organization and matrix deposition were further examined as indicators of ligamentous tissue maturation. Cementogenic activity was evaluated by immunofluorescent staining of cementum protein-1 (CEMP-1) in response to varying biogenic hydroxyapatite (bHA) contents in the bioimplants. The results demonstrated successful reproduction of a PDL-like tissue interface and material-dependent differences in CEMP-1 expression. This platform provides a modular and reproducible tool for the comparative evaluation of bioimplants in a physiologically relevant setting and may be useful in advancing regenerative strategies in dental implantology.