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

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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.