Abstract: Self-Assembled Monolayers (SAMs) on gold were successfully implemented to passivate gold contact organic cell stimulating and sensing transistors. The results show the devices to be greatly insulated from water. This breakthrough is proposed as a technol ogical improvement for bio-stimulation and bio-sensing organic field-effect devices.

Abstract: In this work we report the stimulation of astrocytic calcium signalling using an organic cell sensing and stimulating transistor (O-CST). We demonstrate that astroglial cells can adhere and proliferate on these devices giving us the possibility to stimul ate bioelectrical activity in this type of cells. By the use of a microfluorimetric calcium imaging approach we show that our device is able to evoke an increase in intracellular calcium levels. This research opens a new path in the study of glial cells and their bioelectrical activity.

Abstract: Astroglial ion channels and calcium signalling play a central role in the physiology and pathophysiology of the Central Nervous System. In this context, increasing efforts are needed to generate innovative tool s for monitoring astrocytes biochemical or bioelectrical activity in vitro and in vivo. Organic field effect devices have a great potential for generating advanced biomedical tools to enable real-time recording and manipulation of communicati on signals between neural cells. We previously reported on transparent Organic Cell Stimulating and Sensing Transistors (O-CSTs) that provide bidirectional stimulation and recording of primary neurons. The transparency of the device also all ows the optical imaging of the modulation of the astroglial calcium signalling bioelectrical activity. Here we explore O-CST functionality to stimulate, evoke and control astroglial calcium signalling and whole cell conductance in primary cultured astrocytes. We found thatprimary astroglial cells can adhere, grow and differentiate on the perylene based field-effect transistor. Furthermore does the organic material preserve astrocytes electrophysiological properties. W e show, that the O-CST provides stimulation and thereby evokes intracellular astrocytic calcium response, which can be determined by calcium imaging. The evoked signal was blocked by carbenoxolone and Ruthenium red, thus suggesting i nvolvement of Connexins and TRPV channels. By means of patch-clamp analyses, we explore the effect of the stimulation on the whole-cell conductance of patched astrocytes. We found that the stimulation lead to an exclusive increase in the inward current that could be prevented by application of Ruthenium Red prior to stimulation. This finding suggests a contribution of the transient receptor potential (TRP) channels, of which TRPV-4 has been shown in former studies to mediate Ca2+ influx in astrocytes. Molecular modelling of field distribution obtained by O-CST is also in agreement with experimental data. Our organic cell stimulating and sensing device paves the way to a new generation of devices for stimulation, manipulation and recording of astroglial cells' bioelectrical activity in vitro.