Determination of mechanical properties of biofilms by modelling the deformation measured using optical coherence tomography.
Determination of mechanical properties of biofilms by modelling the deformation measured using optical coherence tomography.
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DOI：
10.1016/j.watres.2018.08.070
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发表时间：
2018-11
期刊：
影响因子：
12.8
通讯作者：
C. Picioreanu;Florian Blauert;H. Horn;M. Wagner
中科院分区：
文献类型：
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作者：
C. Picioreanu;Florian Blauert;H. Horn;M. Wagner
使用诸如光学相干断层扫描（OCT）的非侵入性成像来评估来自变形的生物膜几何形状的材料性质的优点可能受到对作用于生物膜上的流体力所做的假设的损害。本研究开发了一种方法，用于确定生物膜的弹性性能，通过模拟生物膜变形记录的OCT成像与多孔弹性流体-结构相互作用计算。二维生物膜的几何形状提取的OCT扫描的非变形和变形的结构，作为结果的流体动力学负载。生物膜的几何形状被实现在一个模型耦合流体动力学与弹性固体力学和达西流的生物膜。模拟结果进行了比较与真实的变形的几何形状和拟合过程允许在给定的流动条件下的杨氏模量的估计。本发明的方法大大提高了弹性模量的生物膜生长在微型流体矩形通道的估计。这种上级预测是基于在过去的研究中所做的几个简化假设的放松：在生物膜表面上不再取剪切应力恒定，考虑了包括压力在内的总应力，任何生物膜形状都可以用于测定，并且可以估计机械性能的非线性行为。生物膜的弹性模量在70和700 Pa之间，获得和生物膜硬化在大的施加应力，由于流速增加进行了量化。在这里进行的工作开辟了其他机械性能（例如，粘弹性、松弛时间、塑性屈服），并提供了用于模拟生物膜变形和分离的数据，最终应用于生物膜控制和去除策略。
The advantage of using non-invasive imaging such as optical coherence tomography (OCT) to asses material properties from deformed biofilm geometries can be compromised by the assumptions made on fluid forces acting on the biofilm. This study developed a method for the determination of elastic properties of biofilms by modelling the biofilm deformation recorded by OCT imaging with poroelastic fluid-structure interaction computations. Two-dimensional biofilm geometries were extracted from OCT scans of non-deformed and deformed structures as a result of hydrodynamic loading. The biofilm geometries were implemented in a model coupling fluid dynamics with elastic solid mechanics and Darcy flow in the biofilm. The simulation results were compared with real deformed geometries and a fitting procedure allowed estimation of the Young's modulus in given flow conditions. The present method considerably improves the estimation of elastic moduli of biofilms grown in mini-fluidic rectangular channels. This superior prediction is based on the relaxation of several simplifying assumptions made in past studies: shear stress is not anymore taken constant over the biofilm surface, total stress including also pressure is accounted for, any biofilm shape can be used in the determinations, and non-linear behavior of mechanical properties can be estimated. Biofilm elastic moduli between 70 and 700 Pa were obtained and biofilm hardening at large applied stress due to increasing flow velocity was quantified. The work performed here opens the way forin-situdetermination of other mechanical properties (e.g., viscoelastic properties, relaxation times, plastic yields) and provides data for modelling biofilm deformation and detachment with eventual applications in biofilm control and removal strategies.