Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, Bozeman, MT 59715, United States; Department of Chemical and Biological Engineering, Montana State University, 306 Cobleigh Hall, Bozeman, MT 59715, United States.
J Magn Reson. 2018 Aug;293:123-133. doi: 10.1016/j.jmr.2018.06.008. Epub 2018 Jun 22.
F magnetic resonance has been used in the medical field for quantifying oxygenation in blood, tissues, and tumors. The F NMR oximetry technique exploits the affinity of molecular oxygen for liquid fluorocarbon phases, and the resulting linear dependence of F spin-lattice relaxation rate R on local oxygen concentration. Bacterial biofilms, aggregates of bacteria encased in a self-secreted matrix of extracellular polymers, are important in environmental, industrial, and clinical settings and oxygen gradients represent a critical determinant of biofilm function. However, measurement of oxygen distribution in biofilms and biofouled porous media is difficult. Here the ability of F NMR oximetry to accurately track oxygen profile development in microbial impacted packed bed systems without impacting oxygen transport is demonstrated. Time-stable and inert fluorocarbon containing particles are designed which act as oxygen reporters in porous media systems. Particles are generated by emulsifying and entrapping perfluorooctylbromide (PFOB) into alginate gel, resulting in oxygen-sensing alginate beads that are then used as the solid matrix of the packed bed. F oxygenation maps, when combined with H velocity maps, allow for insight into the interplay between fluid dynamics and oxygen transport phenomena in these complex biofouled systems. Spatial maps of oxygen consumption rate constants are calculated. The growth characteristics of two bacteria, a non-biofilm forming Escherichia coli and Staphylococcus epidermidis, a strong biofilm-former, are used to demonstrate the novel data provided by the method.
F 磁共振在医学领域中被用于量化血液、组织和肿瘤中的氧合作用。F NMR 血氧测定技术利用了分子氧对液态氟碳相的亲和力，以及 F 自旋晶格弛豫率 R 与局部氧浓度的线性依赖关系。细菌生物膜是细菌被包裹在自我分泌的胞外聚合物基质中的聚集体，在环境、工业和临床环境中都很重要，而氧梯度是生物膜功能的关键决定因素。然而，生物膜和生物污染多孔介质中氧分布的测量是困难的。本文证明了 F NMR 血氧测定技术在不影响氧传输的情况下，能够准确跟踪微生物冲击填充床系统中氧分布的发展。设计了具有时间稳定性和惰性的含氟碳颗粒，它们在多孔介质系统中充当氧报告器。颗粒是通过乳化和包埋全氟辛基溴（PFOB）制成藻酸盐凝胶而生成的，从而得到氧敏性藻酸盐珠，然后将其用作填充床的固体基质。F 氧图与 H 速度图相结合，可以深入了解这些复杂的生物污染系统中流体动力学和氧传输现象之间的相互作用。计算了氧消耗速率常数的空间图。使用两种细菌的生长特性，即不形成生物膜的大肠杆菌和形成强生物膜的表皮葡萄球菌，来演示该方法提供的新数据。
