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Macrophage Response to Methacrylate Conversion Using a Gradient Approach



Nancy Lin, L A. Bailey, Matthew Becker, N. R. Washburn, Lori Henderson


Incomplete conversion, an ongoing challenge facing photopolymerized methacrylate-based polymers, affects leachables as well as the resulting network. As novel polymers and composites are developed, methods to efficiently screen cell response to these materials and their properties, including conversion, are needed. In this study, an in vitro screening methodology was developed to assess cells cultured directly on cross-linked polymer networks. A gradient in methacrylate double bond conversion was used to increase the experimental throughput. A substrate of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl] propane (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) was prepared with a conversion ranging from 43.0% to 61.2%. Substrates aged for 7 d had no significant differences in surface roughness or hydrophilicity as a function of conversion. Leachables were detectable for at least 7 d using UV-absorption, but their global cytotoxicity was insignificant after 5 d of aging. Thus, culturing RAW 264.7 macrophage-like cells on aged substrates evaluated the cell response to conversion, with possible contributions from the polymer network and the local leachables. Conversions of 45 % and 50 % decreased viability (via calcein/ethidium staining) and increased apoptosis (via annexin-V staining). No significant changes (p > 0.05) in tumor necrosis factor- and interleukin-1 gene expression, as measured by quantitative, real-time reverse transcription-polymerase chain reaction, were seen as conversion increased. Thus, conversions greater than 50 % are recommended for equimolar BisGMA/TEGDMA. The ability to distinguish cell response as a function of conversion is useful as an initial biological screening platform to optimize dental polymers.
Acta Biomaterialia


apoptosis, BisGMA, cytotoxicity, real-time RT-PCR, TEGDMA


Lin, N. , Bailey, L. , Becker, M. , Washburn, N. and Henderson, L. (2007), Macrophage Response to Methacrylate Conversion Using a Gradient Approach, Acta Biomaterialia, [online], (Accessed February 24, 2024)
Created December 31, 2006, Updated October 12, 2021