Diamond-based Platforms for Long-term Growth and Investigations of Neurons

神经科学的最新发展对用于研究完全组织的神经元网络及其活动的材料和设备的性能和功能产生了不断增长的需求。它们应该提供神经元的良好和快速附着，而不应用细胞外基质蛋白，并且在与生物系统接触时不应该随时间降解，从而允许长期测量。薄膜形式的金刚石由于其优异的机械、光学、电学、化学和生物特性而成为此类应用的前景候选者。这项研究计划旨在制备基于超纳米金刚石（UNCD）薄膜的平台，用于功能神经元网络的长期生长及其电生理研究。由金刚石纳米晶体（约100 nm）组成的UNCD膜。5 nm）嵌入无定形碳基质联合收割机中，将极端的金刚石性质与相当光滑的形貌相结合，并且包括纳米结构，其将增强神经元的快速和良好的粘附。在这项工作中，多层超纳米金刚石和金属结构将沉积在玻璃基板上，其透明度允许从背面结合例如从顶部的荧光成像对位于平台上的神经元进行显微镜观察。作为下一步，从这些层，用于记录神经元活动的金属轨道和用于神经元接触垫的UNCD将应用光刻和蚀刻来结构化。由于表面在与细胞的相互作用中起着极其重要的作用，因此将应用通过等离子体或光化学过程对UNCD表面进行的各种修饰，然后进行表面终止的图案化。为了研究层系统的生物相容性和功能性，将使用两种类型的神经元，即蟑螂Rhypharobia maderae的起搏神经元和烟草天蛾Manduca sexta的嗅觉受体神经元，它们分别用作研究自发电活动和发育神经元网络的定向生长的模型，两者都旨在长期研究，这是迄今为止其他材料所无法实现的。

The recent development of neurosciences creates an ever increasing demand to the properties and functionalities of materials and devices used for the study of fully organized neuronal networks and their activity. They should provide good and fast attachment of the neurons without the application of extracellular matrix proteins and should not degrade with the time upon contact with the biological system thus allowing long-term measurements. Diamond in the form of thin films is a perspective candidate for such applications due to its outstanding mechanical, optical, electrical, chemical, and bio-properties. This research proposal aims at the preparation of platforms based on ultrananocrystalline diamond (UNCD) films for the long-term growth of functional neuronal networks and their electrophysiological investigations. The UNCD films which are composed of diamond nanocrystallites (ca. 5 nm) embedded in amorphous carbon matrix combine the extreme diamond properties with a rather smooth topography and include nanostructures which will enhance the fast and good adhesion of the neurons. During this work multilayers of ultrananocrystalline diamond and metal structures will be deposited on glass substrates with a transparency allowing the microscopical observation of the neuron positioned on the platforms from the backside combined with, for example, fluorescence imaging from the top. As a next step, from these layers the metal tracks for recording the neuron activity and the UNCD for the contact pads for the neurons will be structured applying lithography and etching. Since the surface plays an extremely important role in the interactions with cells various modifications of the UNCD surface by plasma or photochemical processes will be applied, followed by patterning of the surface termination. For the investigation of the biocompatibility and functionality of the layer systems two types of neurons will be used, namely pacemaker neurons of the cockroach Rhypharobia maderae and olfactory receptor neurons from the tobacco hornworm Manduca sexta which serve as models for the investigation of the spontaneous electrical activity and the directional growth of developing neuronal networks, respectively, both aiming at long-term studies, not achieved till now with other materials.