1 Volpe Research Center, American Dental Association Foundation, Frederick, MD, USA.
J Dent Res. 2019 Aug;98(9):1037-1044. doi: 10.1177/0022034519858975.
The increasing use of methacrylate-based materials in tissue engineering and dental restorations demands detailed evaluation of enzymolysis of these materials due to toxicity, durability, and biocompatibility concerns. The objective of this study is to develop tools for assessing and ranking the enzymolysis kinetics of dimethacrylate (DMA) compounds. Triethyleneglycol DMA and diurethane DMA are employed as model DMAs for kinetic studies of 2-step enzymolysis by 2 esterases, pseudocholine esterase and cholesterol esterase. In addition, the intermediate hydrolysis products, mono-methacrylates (mono-MAs), are prepared via esterases. The kinetics of DMA enzymolysis are evaluated per the concentrations of DMA. The enzymolysis products are quantified by high-performance liquid chromatography. Additionally, stoichiometric analysis and a Berkeley Madonna model are employed to compare the efficacy of esterases in DMA enzymolysis. The chemical structure of mono-MAs is verified by proton and heteronuclear single quantum coherence (2D H-C) nuclear magnetic resonance spectroscopy and mass spectrometry. In evaluating the ratio of sequential and simultaneous degradations of DMA and mono-MA, the stoichiometric analysis draws the same conclusions without using [mono-MA] as the experimental observation using [mono-MA]. The majority of the 4 esterase-DMA combinations undergo the sequential enzyme-catalyzed hydrolysis, from DMA to mono-MA to diol. However, cholesterol esterase is more effective than pseudocholine esterase in maintaining sequential degradation until >90% of DMA is decomposed. Both enzymolysis steps are first-order reactions. The mono-MAs are more hydrolysis resistant than DMAs. Moreover, esterase efficacy and selectivity on DMA enzymolysis are presented. The stoichiometric analysis provides valuable tools in assessing DMA enzymolysis when mono-MA is difficult to be obtained. The resistance of mono-MAs to enzymolysis suggests a need for thorough toxicity evaluations of these intermediate compounds. It also advocates the alternative approaches in designing and developing durable and biocompatible materials.
由于毒性、耐久性和生物相容性等问题，甲基丙烯酸酯基材料在组织工程和牙科修复中的应用越来越广泛，因此需要对这些材料的酶解进行详细评估。本研究旨在开发用于评估和排序二甲基丙烯酸酯（DMA）化合物酶解动力学的工具。三甘醇二甲基丙烯酸酯和二尿烷二甲基丙烯酸酯被用作两步酶解的模型 DMA，由两种酯酶，假性胆碱酯酶和胆固醇酯酶进行。此外，通过酯酶制备中间水解产物，单甲基丙烯酸酯（mono-MA）。通过 DMA 的浓度评估 DMA 酶解动力学。通过高效液相色谱定量分析酶解产物。此外，还采用化学计量分析和伯克利 Madonna 模型比较了酯酶在 DMA 酶解中的效率。通过质子和异核单量子相干（2D H-C）核磁共振波谱和质谱验证 mono-MA 的化学结构。在评估 DMA 和 mono-MA 的顺序和同时降解的比例时，化学计量分析得出了与不使用 [mono-MA] 作为实验观察的相同结论。在大多数 4 种酯酶-DMA 组合中，DMA 到 mono-MA 到二醇的顺序酶催化水解占主导地位。然而，与假性胆碱酯酶相比，胆固醇酯酶在维持顺序降解方面更有效，直到 >90%的 DMA 被分解。两步酶解均为一级反应。mono-MA 比 DMA 更具抗水解性。此外，还提出了酯酶对 DMA 酶解的功效和选择性。当难以获得 mono-MA 时，化学计量分析为评估 DMA 酶解提供了有价值的工具。mono-MA 对酶解的抵抗力表明需要对这些中间化合物进行彻底的毒性评估。它还提倡在设计和开发耐用和生物相容的材料时采用替代方法。
