Parahydrogen-Induced Hyperpolarisation For Microfluidic Perfusion Culture

核磁共振是研究生物和非生物的结构、组成和动力学的最强大的工具之一。它的灵敏度受到核自旋排列程度的限制，即使在最强的磁体中，这一程度也很小。超极化技术，如对氢诱导的极化可以产生更好的旋转对齐，提供相应的灵敏度增加。parQChip的目标是通过将对氢诱导极化(PhIP)的所有步骤集成到芯片上，提供具有超极化代谢物(丙酮酸、富马酸)的细胞的芯片上实验室(LoC)培养，用于高灵敏度的代谢核磁共振监测。为此，我们提出了一个跨学科的研究计划，使用自旋动力学、传输和动力学过程的定量建模，并结合反应和传输动力学的实验量化，为微流控芯片布局、核磁共振检测器、射频脉冲序列和操作参数(如流速、试剂浓度、溶剂和温度)的设计提供信息。主要的挑战在于氢化、极化转移和纯化步骤的协同操作，这些步骤都必须在核松弛破坏超极化之前完成。拟议的研究包括四个工作包，每个工作包由一个Co-PI领导。WP 1(Kuprov)专注于建模，使用了一种新的方法，在相同的基础上处理自旋和空间自由度。WP 2(Levitt)处理从对氢自旋顺序到目标代谢物所需的极化转移。这就需要设计一种新型的微流控核磁共振探针系统，该系统具有用于转移步骤和下游观察的独立检测器。WP3(Whitby)将专注于化学方面，包括氢化、切割和纯化。最后，WP4(Utz)处理这些步骤的微流控集成。LoC设备提供对细胞、组织(“芯片上的器官”)和小生物体的生长条件的详细控制，为诊断和治疗的发展以及药物安全性测试提供有价值的模型。核磁共振光谱学在这方面可能非常有用，因为它允许对代谢过程进行非侵入性量化。然而，常规核磁共振的有限灵敏度在微升体积的LoC设备中加剧。ParQ芯片将解决这一问题，将检测极限从毫摩尔浓度范围向下推至微摩尔。这将允许在微流体细胞培养以及组织和器官模型中详细地原位观察代谢过程，在疾病建模、药物测试和生命科学的其他方面有许多应用。PhIP的微流体实现也将导致对氢化反应机制和NuclearSpin弛豫过程之间的相互作用的更深层次的理解。通过PARQ芯片开发和验证的计算工具将有助于超极化磁共振成像技术的发展。

Nuclear magnetic resonance (NMR) is one of the most powerful tools forinvestigating the structure, composition, and dynamics of living and non-livingmatter. Its sensitivity is limited by the degree of alignment of nuclear spins,which is small even in the strongest magnets. Hyperpolarisation techniquessuch as parahydrogen-induced polarisation can produce much better spinalignments, offering corresponding increases in sensitivity.paraQchip aims provide lab-on-a-chip (LoC) cultures of cells with hyperpolarisedmetabolites (pyruvate, fumarate) for high-sensitivity NMR monitoring of metabolism,by integrating all steps of parahydrogen-induced polarisation (PHIP) onto thechip. To this end, we propose an interdisciplinary research programme that usesquantitative modelling of spin dynamics, transport, and kinetic processesin tandem with experimental quantification of reaction and transport kinetics toinform the design of the microfluidic chip layout, NMR detector, radiofrequencypulse sequences, and operation parameters such as flow rates, reagent concentrations,solvents, and temperature. The main challenge lies in the concerted operationof the hydrogenation, polarisation transfer, and purification steps, whichmust all be completed before nuclear relaxation destroys the hyperpolarisation.The proposed research consists of four work packages, each led by oneof the Co-PIs. WP 1 (Kuprov) focusses on modelling, using a novel approachthat treats spin and spatial degrees of freedom on an equal footing.WP 2 (Levitt) deals with the required transfer of polarisation from theparahydrogen spin order to the target metabolite. This requires designof a novel microfluidic NMR probe system with separate detectors forthe transfer step and for downstream observation. WP 3 (Whitby) will focuson the chemical aspects, including hydrogenation, cleavage, and purification.Finally, WP 4 (Utz) deals with the microfluidic integration of these steps.LoC devices provide detailed control over the growth conditions of cells,tissues ("organ-on-a-chip"), and small organisms, providing valuable modelssupporting the development of diagnostics and therapies, and drug safetytesting. NMR spectroscopy could be of great use in this context, as it allowsnon-invasive quantification of metabolic processes. However, the limitedsensitivity of conventional NMR is exacerbated at the microlitre volumescale of LoC devices. paraQchip will address that, pushing the limitof detection from the millimolar concentration range down to micromolar. This willallow detailed in-situ observation of metabolic processes in microfluidiccell cultures as well as tissue and organ models, with many applicationsin disease modelling, drug testing, and other aspects of the life sciences.Microfluidic implementation of PHIP will also lead to deeper understandingof the interplay between the hydrogenation reaction mechanism and nuclearspin relaxation processes. The computational tools developed and validatedthrough paraQchip will benefit the development of hyperpolarised magneticresonance imaging techniques.