Theoretical and Applied Mechanics Program, Northwestern University.
Civil and Environmental Engineering Department, Northwestern University.
J Vis Exp. 2024 Mar 1(205). doi: 10.3791/66118.
Biofilms are complex biomaterials comprising a well-organized network of microbial cells encased in self-produced extracellular polymeric substances (EPS). This paper presents a detailed account of the implementation of optical coherence elastography (OCE) measurements tailored for the elastic characterization of biofilms. OCE is a non-destructive optical technique that enables the local mapping of the microstructure, morphology, and viscoelastic properties of partially transparent soft materials with high spatial and temporal resolution. We provide a comprehensive guide detailing the essential procedures for the correct implementation of this technique, along with a methodology to estimate the bulk Young's modulus of granular biofilms from the collected measurements. These consist of the system setup, data acquisition, and postprocessing. In the discussion, we delve into the underlying physics of the sensors used in OCE and explore the fundamental limitations regarding the spatial and temporal scales of OCE measurements. We conclude with potential future directions for advancing the OCE technique to facilitate elastic measurements of environmental biofilms.
生物膜是一种复杂的生物材料，由微生物细胞组成的有序网络组成，这些细胞被自身产生的细胞外聚合物（EPS）包裹。本文详细介绍了针对生物膜弹性特性进行的光学相干弹性测量（OCE）的实施情况。OCE 是一种非破坏性的光学技术，可用于以高时空分辨率对部分透明的软材料的微观结构、形态和粘弹性特性进行局部映射。我们提供了一个全面的指南，详细说明了正确实施该技术的基本步骤，以及一种从收集的测量中估计颗粒生物膜的体积杨氏模量的方法。这些步骤包括系统设置、数据采集和后处理。在讨论中，我们深入研究了 OCE 中使用的传感器的基础物理学，并探讨了 OCE 测量的空间和时间尺度的基本限制。最后，我们提出了推进 OCE 技术以促进环境生物膜弹性测量的潜在未来方向。
