Polystyrene substrate effects on human dental pulp cell behavior: implications for in vitro culture optimization.

Objective: This study aimed to test the hypothesis that human dental pulp cells (hDPCs) exhibited differential responses to non-tissue culture treated polystyrene (Non-TCPS) and TCPS in the context of odontogenic differentiation and mineralization.

Methods: hDPCs were seeded onto commercially available Non-TCPS and TCPS substrates. Following cultivation in odontogenic media (OM) for either 14 or 20 days, matrix mineralization was assessed using alizarin red staining. Gene expression analysis of odontogenic and inflammatory markers was conducted at day 7 and 14 using reverse transcription quantitative polymerase chain reaction (RT-qPCR). The experimental design comprised four primary groups, namely: Non-TCPS 5% FBS/ Non-TCPS 10% FBS/ TCPS 5% FBS/ TCPS 10% FBS. Within each primary group, two secondary experimental conditions were established: maintenance media (MM) and OM.

Results: Significant differences in cell mineralization were observed between TCPS and Non-TCPS substrates. The mineralization of hDPCs was markedly more pronounced in TCPS OM compared to Non-TCPS OM, irrespective of the culture duration. Additionally, there were minor variations in staining intensity between the 5% FBS and 10% FBS groups within the TCPS condition. In contrast, Non-TCPS exhibited extremely weak staining even in the presence of higher FBS concentration (10% FBS OM). These findings suggest that surface properties plays a more dominant role over serum concentration in determining cell mineralization. Regarding the gene expression results, significant differences in odontogenic and pro-inflammatory gene expression were detected between OM and MM within the TCPS 5% FBS category. This finding further supports the hypothesis that surface properties play more important role in determining odontogenic differentiation of hDPCs. Additionally, the concentration of serum in the culture medium warrants consideration, as a higher serum concentration (10% FBS) may partially masked the promotive effect of OM.

Conclusions: The results indicate that surface properties play a pivotal role in determining the fate of hDPCs with respect to odontogenic differentiation and mineralization.