Glial interfaces impact on astrocytes physiology and validation of glioelectronic devices for stimulation and read-out of astrocytes in vitro.

Astrocytes, once considered merely supportive cells in the nervous system, are now recognised as active participants in brain information processing. However, despite astrocytes’ critical roles in health and disease, most state-of-the-art technologies for the study of brain functions and treatment of brain dysfunctions have been developed from a neurocentric perspective and remain primarily focused on neurons. This study employs novel tools and nanotechnologies to target specific astrocytic functions, including calcium signalling and electrophysiological properties, whose dysfunction contributes to both acute and chronic pathologies The effect of 40 Hz light stimulation utilising an Invisible Spectral Flicker (ISF) on calcium dynamics in vitro is investigated, demonstrating that visible light of different properties can induce diverse Ca²⁺ dynamics. Selective pharmacological approaches are employed to elucidate the underlying mechanisms and identify the ion channels involved in these calcium dynamics. The biocompatibility of a novel microelectrode array (MEA) based on zinc oxide nanorods coated with reduced graphene oxide is demonstrated. The viability of astrocytes on these novel devices is confirmed, laying the groundwork for astroglial extracellular recordings. Preliminary results indicate the devices' sensitivity to low-amplitude astrocytic signals, paving the way for a deeper understanding of astrocytic function within the neural environment. Finally, the capability of simultaneous electrophysiological recording combined with calcium microfluorometry, and voltage-sensitive dye imaging is investigated, demonstrating their temporal correlation. Overall, this work validates three novel approaches as promising glial interfaces for the study and modulation of astrocytes.