Agradecimentos: We acknowledge Dr. Anibal Diogenes (University of Texas) for the donation of SCAPs. We acknowledge expert technical assistance from Dr. Crystal Chaw in the Advanced Light Microscopy Core at the Jungers Center at Oregon Health & Science University. This project was supported by funding from the National Institute of Dental and Craniofacial Research (R01DE026170 and 3R01DE026170-03S1 to LEB), the Oregon Clinical & Translational Research Institute (OCTRI) - Biomedical Innovation Program (BIP), the Innovation in Oral Care Awards sponsored by GlaxoSmithKline (GSK), International Association for Dental Research (IADR), the Michigan-Pittsburgh-Wyss Resource Center – Regenerative Medicine Resource Center (MPW-RM), the OHSU Fellowship for Diversity and Inclusion in Research (OHSU-OFDIR to CMF). The authors declare no potential conflicts of interest with respect to the authorship and/or publication of this article Ver menos

Abstract: The tooth has a unique configuration with respect to biomaterials that are used for its treatment. Cells inside of the dental pulp interface indirectly with biomaterials via a calcified permeable membrane, formed by a dentin barrier which is composed of several thousands of dentinal tubules (~2 µm in diameter) connecting the dental pulp tissue to the outer surface of the tooth. Although the cytotoxic response of the dental pulp to biomaterials has been extensively studied, there is a shortage of in vitro model systems that mimic the dentin-pulp interface, enabling an improved understanding of the morphologic, metabolic and functional influence of biomaterials on live dental pulp cells. To address this shortage, here we developed an organ-on-a-chip model system which integrates cells cultured directly on a dentin wall within a microdevice which replicates some of the architecture and dynamics of the dentin-pulp interface. The tooth-on-a-chip is made out of molded polydimethylsiloxane (PDMS) with a design consisting of two chambers separated by a dentin fragment. To characterize pulp cell responses to dental materials on-chip, stem cell-derived odontoblasts were seeded onto the dentin surface, and observed using live-cell microscopy. Standard dental materials used clinically (2-hydroxyethylmethacrylate - HEMA, Phosphoric Acid - PA, and Adper-Scotchbond - SB) were tested for cytotoxicity, cell morphology and metabolic activity on-chip, and compared against standardized off-chip controls. All dental materials had cytotoxic effects in both on-chip and off-chip systems in the following order: HEMA>SB>PA (p<0.05), and cells presented consistently higher metabolic activity on-chip than off-chip (p<0.05). Furthermore, the tooth-on-a-chip enabled real-time tracking of odontoblast monolayer formation, remodeling, and death in response to biomaterial treatments, and gelatinolytic activity in a model hybrid layer (HL) formed in the microdevice. In conclusion, the tooth-on-a-chip is a novel platform that replicates near-physiologic conditions of the pulp-dentin interface, and enables live-cell imaging to study dental pulp cell response to biomaterials Ver menos