Ultra-low noise PEDOT:PSS electrodes on bacterial cellulose: A sensor to access bioelectrical signals in non-electrogenic cells

• Published in: Organic electronics 2020-10, Vol.85, p.105882, Article 105882
• Main Authors: Inácio, Pedro M.C., Medeiros, Maria C.R., Carvalho, Tiago, Félix, Rute C., Mestre, Ana, Hubbard, Peter C., Ferreira, Quirina, Morgado, Jorge, Charas, Ana, Freire, Carmen S.R., Biscarini, Fabio, Power, Deborah M., Gomes, Henrique L.
• Format: Article
• Language: English
• Subjects: Bacterial cellulose; Extra-cellular electrodes; Non-excitable cells; PEDOT:PSS; Printed electronics
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2020.105882

This study is focused on the particular advantages of organic-based devices to measure cells that do not generate action potentials, also known as non-electrogenic cells. While there is a vast literature about the application of organic conductors to measure neurons, cardiomyocytes and brain tissues, electrical measurements of non-electrogenic cells are rare. This is because non-electrogenic cells generate weak signals with frequencies below 1 Hz. Designing low noise devices in a millihertz frequency range is extremely challenging due to the intrinsic thermal and 1/f type noise generated by the sensing electrode. Here, we demonstrate that the coating of cellulose nanofibers with conducting PEDOT:PSS ink allows the fabrication of a nanostructured surface that establishes a low electrical double-layer resistance with liquid solutions. The low interfacial resistance combined with the large effective sensing area of PEDOT:PSS electrodes minimizes the thermal noise and lowers the amplitude detection limit of the sensor. The electrode noise decreases with frequency from 548 nV r.m.s at 0.1 Hz to a minimum of 6 nV r.m.s for frequencies higher than 100 Hz. This low noise makes it possible to measure low frequency bioelectrical communication signals, typical of non-electrogenic cells, that have until now been difficult to explore using metallic-based microelectrode arrays. The performance of the PEDOT:PSS-based electrodes is demonstrated by recording signals generated by populations of glioma cells with a signal-to-noise ratio as high as 140. [Display omitted] •PEDOT:PSS-based electrodes in low frequency electrophysiology studies.•PEDOT:PSS/electrolyte interfaces have a very low intrinsic noise.•Charging effects on PEDOT:PSS electrodes improve the SNR in biosignal recordings.•PEDOT:PSS-based electrodes provide access to signals in non-electrogenic cells.