Real-time xCELLigence impedance analysis of the cytotoxicity of dental composite components on human gingival fibroblasts

Objectives. Aim of this study was by continuous monitoring to assay the proliferative capacity of human gingival fibroblasts (HGFs), to investigate cytotoxicity of the most common monomers/comonomers in dental resin composites: bisphenol-A-glycidylmethacrylate (BisGMA), hydroxyethylenemethacrylate (HEMA), triethyleneglycoldimethacrylate (TEGDMA), and urethanedimethacrylate (UDMA) in HGFs during 24h exposure using the xCELLigence system. Methods. xCELLigence cell index (CI) impedance measurements were performed according to the instructions of the supplier. HGFs were resuspended in medium and subsequently adjusted to 400,000, 200,000, 100,000, and 50,000 cells/mL. After seeding 100 mu L of the cell suspensions into the wells of the E-plate 96, HGFs were monitored every 15 min for a period of up to 18h by the xCELLigence system. Results. Half maximum effect concentrations (EC50) were determined based on the dose-response curves derived by xCELLigence measurements. Following real-time analysis, significantly increased EC50 values of HGFs exposed for 24h to the following substances were obtained: HEMA(a), TEGDMA(b), UDMA(c). The EC50 values (mean [mmol/L] +/- S.E.M.; n = 5) were: HEMA 11.20 +/- 0.3, TEGDMA(a) 3.61 +/- 0.2, UDMA(a,b) 0.20 +/- 0.1, and BisGMA(a,b,c) 0.08 +/- 0.1. These results are similar to the EC50 values previously observed with the XTT end-point assay. Significance. Our data suggests that the xCELLigence live cell analysis system offers dynamic live cell monitoring and combines high data acquisition rates with ease of handling. Therefore, the xCELLigence system can be used as a rapid monitoring tool for cellular viability and be applied in toxicity testing of xenobiotics using in vitro cell cultures. Crown Copyright (C) 2009 Published by Elsevier Ltd on behalf of Academy of Dental Materials. All rights reserved.