Seeing through porous media: An experimental study for unveiling interstitial flows
Seeing through porous media: An experimental study for unveiling interstitial flows
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DOI：
10.1002/hyp.11425
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发表时间：
2018-01
影响因子：
3.2
通讯作者：
S. Rubol;D. Tonina;L. Vincent;Jill A. Sohm;W. Basham;R. Budwig;P. Savalia;E. Kanso;D. Capone;K. Nealson
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文献类型：
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作者：
S. Rubol;D. Tonina;L. Vincent;Jill A. Sohm;W. Basham;R. Budwig;P. Savalia;E. Kanso;D. Capone;K. Nealson
我们描述了一种新的廉价的方法，利用粒子图像测速（PIV）和折射率匹配（RIM）的可视化和量化的生物修正多孔介质内的流场。迄今为止，这种技术仅限于理想化的颗粒，其折射率与淡水的折射率不匹配，因此需要专门的并且通常有毒或危险的流体。在这里，我们使用由水凝胶制成的不规则形状的颗粒作为固体基质，水作为流体。利用水的好处是，它提供了，第一次，有机会研究水力和生物过程，这通常发生在土壤和河床。通过使用RIM结合PIV（RIM-PIV），我们测量了填充有颗粒材料的细胞内的间隙流场，该颗粒材料由尺寸范围为1-8 mm的水凝胶颗粒组成，在存在和不存在苜蓿中华根瘤菌细菌（菌株Rm 8530）的情况下。我们还使用荧光示踪剂（荧光素）和荧光微生物（希瓦氏菌GPF MR-1）进行了实验，以测试可视化溶质转运和微生物运动的能力。结果表明，RIM-PIV可以测量无生物膜和生物膜覆盖的水凝胶颗粒的流场。荧光示踪剂注射显示出可视化物理（凹面和涡流）和生物（生物膜）瞬态存储区的能力，而荧光微生物处理显示出跟踪流体内微生物运动的能力。我们的结论是，所提出的方法是一个很有前途的工具，可视化和量化生物膜附着，生长和分离的系统更接近自然条件比2D流动池实验。
We describe a novel inexpensive method, utilizing particle image velocimetry (PIV) and refractive index‐matching (RIM) for visualizing and quantifying the flow field within bio‐amended porous media. To date, this technique has been limited to idealized particles, whose refractive index does not match that of fresh water and thus requires specialized and often toxic or hazardous fluids. Here, we use irregularly shaped grains made of hydrogel as the solid matrix and water as the fluid. The advantage of using water is that it provides, for the first time, the opportunity to study both hydraulic and biological processes, which typically occur in soils and streambeds. By using RIM coupled with PIV (RIM‐PIV), we measured the interstitial flow field within a cell packed with granular material consisting of hydrogel grains in a size range of 1–8 mm, both in the presence and in the absence of Sinorhizobium meliloti bacteria (strain Rm8530). We also performed experiments with fluorescent tracer (fluorescein) and fluorescent microbes (Shewanella GPF MR‐1) to test the capability of visualizing solute transport and microbial movements. Results showed that the RIM‐PIV can measure the flow field for both biofilm‐free and biofilm‐covered hydrogel grains. The fluorescent tracer injection showed the ability to visualize both physical (concave surfaces and eddies) and biological (biofilms) transient storage zones, whereas the fluorescent microbe treatment showed the ability to track microbial movements within fluids. We conclude that the proposed methodology is a promising tool to visualize and quantify biofilm attachment, growth, and detachment in a system closer to natural conditions than a 2D flow cell experiment.