Ultrasensitive gold micro-structured electrodes enabling the detection of extra-cellular long-lasting potentials in astrocytes populations

• Autor(a) principal: Mestre, Ana L. G.
• Data de Publicação: 2017
• Outros Autores: Cerquido, Monica, INÁCIO, PEDRO, Asgarifar, Sanaz, Lourenco, Ana S., Lurdes S. Cristiano, M., Aguiar, Paulo, Medeiros, Maria C. R., Araújo, Inês, Ventura, Joao, Gomes, Henrique L.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/11881
• topic: Calcium waves; In-Situ; Impedance spectroscopy; Microelectrode arrays; Conducting polymers; Neural interfaces; Oscillations; Networks; Culture; Noise

Ultra-sensitive electrodes for extracellular recordings were fabricated and electrically characterized. A signal detection limit defined by a noise level of 0.3-0.4 mu V for a bandwidth of 12.5 Hz was achieved. To obtain this high sensitivity, large area (4 mm(2)) electrodes were used. The electrode surface is also micro-structured with an array of gold mushroom-like shapes to further enhance the active area. In comparison with a flat gold surface, the micro-structured surface increases the capacitance of the electrode/electrolyte interface by 54%. The electrode low impedance and low noise enable the detection of weak and low frequency quasi-periodic signals produced by astrocytes populations that thus far had remained inaccessible using conventional extracellular electrodes. Signals with 5 mu V in amplitude and lasting for 5-10 s were measured, with a peak-to-peak signal-to-noise ratio of 16. The electrodes and the methodology developed here can be used as an ultrasensitive electrophysiological tool to reveal the synchronization dynamics of ultra-slow ionic signalling between non-electrogenic cells.