NeuroExaminer - a microfluidic device for physiology-based neural circuit analysis

精神疾病影响着世界上大量的人口。毫不奇怪，给儿童和青少年以及成年人开的神经调节药物处方不断增加，尤其是在发达的西方国家。然而，这些药物对整个大脑生理的影响，包括不是治疗干预主要目标的脑室和脑回路，几乎不为人所知，而且在近期和中期不太可能出现适合人类的诊断方法。然而，在其他脊椎动物（如Zerafish）的大脑中进行类似的药物表征研究将会提供信息，因为大脑回路具有高度的进化守恒性。在拟议的研究中，我们将开发一种新的装置来揭示神经调节药物给药制度对全脑的生理后果。核心是一个微型装置，被称为NeuroExaminer，通过先进的微制造方法建立，允许精确的化学刺激，并可以与亚秒时间尺度的细胞分辨率的全脑光片显微镜相结合。然而，通常用于微流体的材料，如PDMS，不仅表现出相对较高的自动荧光，导致成像中的噪声，而且还倾向于吸收化学成分，导致很大程度上不确定的刺激浓度。因此，NeuroExaminer将包含由玻璃制成的微通道或由玻璃与两个光子聚合元素的组合制成的微通道，用于精确控制的化合物应用，具有亚秒级分辨率和陡峭的浓度梯度形成。这将有助于揭示任何水溶性化合物的药代动力学和神经调节功能。在这个项目的过程中，我们将通过使用NeuroExaminer来研究两种不同的精神兴奋剂引起的全脑改变，通过连续监测至少一个小时的细胞分辨率的神经元活动，来进行概念验证。这将证明NeuroExaminer是一种强大的新型仪器，可以揭示药物的特定神经活动，包括它们在神经调节实现之前的滞后时间，以及以时间依赖的方式激活或抑制回路。此外，我们的工作将提供一种急需的方法来揭示神经回路的基本见解，并允许测试任何水溶性化合物可能的神经调节作用。因此，神经科学的基础研究、药物开发和验证的药物研究以及评估药物安全性的公共当局都将受益于NeuroExaminer。最终，由NeuroExaminer提供的新的神经生理学诊断将有助于神经精神疾病的新颖和更好的治疗。

Psychiatric disorders affect a large number of the worldwide population. Not surprisingly, prescriptions of neuromodulatory drugs for young children and juveniles, but also adults are constantly rising, in particular in the developed western countries. The implications of these drugs on the physiology of the entire brain, including brain compartments and circuits that are not the primary target of therapeutic intervention, however, are barely understood and suitable diagnostic approaches for humans are unlikely in the near and medium-term future. However, analogous drug characterization studies in brains of other vertebrates, such as the Zerafish, will be informative due to the high evolutionary conservation of the brain circuitry. In the proposed research we will develop a novel device to reveal the physiological consequences of neuromodulatory drug administration regimes on the whole brain in vivo. The core is a miniature device – termed NeuroExaminer – established by advanced methods of microfabrication that allows for precise chemical stimulations and can be combined with whole brain light-sheet microscopy with cellular resolution at the subsecond time-scale. Typically used materials for microfluidics, such as PDMS, however exhibit not only a relatively high auto fluorescence that leads to noise in the imaging, but also the tendency to absorb chemical components, resulting in largely undefined stimuli concentrations. The NeuroExaminer will thus contain microchannels made from glass or from combinations of glass with two photon polymerized elements for precisely controlled compound application with subsecond resolution and steep concentration gradient formation. This will enable to reveal the pharmacokinetics and neuromodulatory functions of any water-soluble compound. In the course of the project we will develop a proof of concept by using the NeuroExaminer to investigate brain-wide alterations induced by two different psychostimulants through continuously monitoring neuronal activity at cellular resolution over at least one hour. This will demonstrate that the NeuroExaminer is a powerful novel instrument to reveal the specific neural activity of drugs, including their lag time until neuromodulation is achieved together with circuit activation or repression in a time-dependent manner. Moreover, our work will provide a much needed method to reveal fundamental insights into neural circuits and allow to test any water soluble compound for a possible neuromodulatory effect. Therefore, basic research in neuroscience, pharmaceutical research for drug development and validation as well as public authorities for evaluating drug safety will profit from the NeuroExaminer. Ultimately, the access to novel neurophysiological diagnostics provided by the NeuroExaminer will help to contribute to novel and better treatments of neuropsychiatric disorders.