Novel MR Selective Imaging of Transport and Growth in Biofilms

理解流体力学和化学反应的耦合关系是许多化学过程的核心。该项目旨在实施和开发化学特异性、空间分辨的磁共振（MR）测量技术，该技术能够在光学不透明的复杂孔隙结构中量化、明确地传输（流动和扩散）和化学成分/转换。在此背景下要解决的案例研究是生物膜控制、代谢和矿化，它们提供了相对“MR友好”（就信号松弛时间而言）的测试系统，在此基础上开发和应用基于核（1H以外）的适当MR测量方法。生物膜由包裹在排泄的聚合物质（EPS）基质中的微生物组成，其目的是将它们固定在固体支撑表面上。它们在工程能力中广泛遇到，从用于污染控制的生物反应器和地下生物膜屏障（在这种情况下，生物膜的生长和保留是可取的）到工艺设备、水道和采油井附近岩石的生物污染（在这种情况下，微生物的保留是非常不可取的），以及各种医疗应用（例如导尿管）。营养物质进入微生物的运输/积累以及代谢产物离开微生物对微生物的生长至关重要，而杀菌剂进入生物膜是限制其功效的主要因素。我们控制或利用生物膜形成的能力的一个主要限制在于没有容易获得的中观和宏观尺度运输和这些复杂系统中发生的化学的定量描述。多核磁共振，由于其非侵入性，化学选择性的性质，除了其量化运输的能力，将发展提供这样的定量描述。到目前为止，核磁共振技术的许多方面尚未得到证实。然而，这项研究的突破性进展将广泛应用于反应、储层和组织工程以及材料处理，并提供重要的信息，可用于解决一个不起眼但重要的医学问题（导管生物污染），这是导致许多老龄化人口和易感脊柱损伤患者死亡的一个原因。

Understanding the coupling of hydrodynamics and chemical reaction lies at the heart of many chemical processes. This project aims to implement and develop chemically-specific, spatially-resolved magnetic resonance (MR) measurement techniques, that are able to quantify, unambiguously, transport (both flow and diffusion) and chemical composition/conversion within an optically opaque complex pore structure. The case studies to be addressed in this context are of biofilm control, metabolism and mineralization, which provide relatively 'MR friendly' (in terms of signal relaxation times) test systems upon which to develop and apply appropriate MR measurement methods based on nuclei other than 1H. Biofilms consist of micro-organisms encased in an excreted polymeric substances (EPS) matrix, the purpose of which is to anchor them onto the solid support surface. They are widely encountered in engineering capacities, ranging from bioreactors and subsurface biofilm barriers for pollution control (in which biofilm growth and retention is desirable) to bio-fouling (in which case micro-organism retention is highly undesirable) of process equipment, water courses and rock near oil-recovery wells, as well as in various medical applications (e.g. urinary catheters). Transport/accumulation of nutrients into, and metabolic products away from, the micro-organisms is crucial to their growth, while penetration of biocides into biofilms is a major factor which limits their efficacy. A major limitation in our ability to either control or exploit biofilm formation lies in there being no easily accessible quantitative description of the meso- and macro-scale transport and chemistry occurring within these complex systems. Multi-nuclear MR, by virtue of its non-invasive, chemically-selective nature, in addition to its ability to quantify transport, will be developed to provide such a quantitative description. Various aspects of the MR technique are, as yet, unproven. However the ground broken in this study will be widely applicable in reaction, reservoir and tissue engineering, and materials processing, as well as providing vital information that could be used to tackle an unglamorous but important medical problem (catheter bio-fouling) which is a contributory cause of death for many of our ageing population and susceptible spinal injury patients.