Organic Bio-Electronics for Interfacing, Stimulating and Recording of Neural Cells

One of the main reasons for the difficulty of providing a treatment of a huge number of disorders of the brain is the lack of deeper insight on how it works. Even after centuries of research, there are no efficient tools at hand to create this deeper insight. Recently, an increasing attention is focused on organic bioelectronics, aimed at engineering, fabrication and characterization of improved biocompatible, conformable and low cost processing devices that enable stimulation and recording of neural cells to provide an unprecedented insight into the brain’s physiology and pathophysiology. These new devices are hot candidates in order to create efficient tools for research and diagnosis and to establish a working ’machine-to-brain’ communication. Still there is room for improvement in the used materials, for example in the biocompatibility. To this aim, a novel quaterthiophene (T4) semiconductor, covalently modified with lysine- ends (T4Lys), was fabricated and characterized. The material was then tested as interface for DRG primary neurons. By whole-cell patch-clamp, it was examined if the biofunctionality of neurons cultured on T4Lys was preserved and if this organic interface enabled functional differentiation of DRG primary neurons. Not only neurons but also astrocytes, their ion channels and calcium signaling play a crucial role in the physiology and pathophysiology of the central nervous system. In this context novel tools are needed to also monitor and/or modulate the astrocytic biochemical and bioelectrical activity. To this end, an organic field effect transistor device (O-CST), was interfaced with astroglial cells. In this context the biocompatibility of the organic material P13 and its preservation of the astrocytic electrophysiological properties in vitro was investigated, and the impact of a P13-based organic field effect transistor on the astrocytic ionic conductance studied. The evoked response to device stimulation was characterized and the necessity of device integrity investigated.