resumo
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.
palavras-chave
CONDUCTING POLYMERS; MEMBRANES; CALCIUM; DELIVERY; TRANSISTOR; NETWORKS
categoria
Materials Science; Physics
autores
Inacio, PMC; Medeiros, MCR; Carvalho, T; Felix, RC; Mestre, A; Hubbard, PC; Ferreira, Q; Morgado, J; Charas, A; Freire, CSR; Biscarini, F; Power, DM; Gomes, HL
Grupos
agradecimentos
We gratefully acknowledge support from the Portuguese Foundation for Science and Technology (FCT/MCTES), through national funds and when applicable co-funded EU funds by FEDER under the PT 2020 Partnership Agreement.; The projects contributing to this work are the following ones: PTDC/EEIAUT/5442/2014 (Implantable organic devices for advanced therapies, INNOVATE), UIDB/EEA/50008/2020 (Instituto de Telecomunicacoes, IT), UIDB/Multi/04326/2020 (Centro de Ciencias do Mar, CCMar), and CICECO -Aveiro Institute of Materials (UIDB/50011/2020 & UIDP/50011/2020). RCF was funded by FCT, under the Norma Transit.oria -DL57/2016/CP1361/project CT0020 and AM was funded by an FCT PhD grant SFRH/BD/148688/2019.