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Pedro M. C. Inácio
University of the Algarve
Analytical chemistryElectrodeElectrophysiologyExtracellularElectrolyte
10Publications
3H-index
25Citations
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Publications 10
Newest
#1Sanaz Asgarifar (University of the Algarve)H-Index: 2
#2Ana L. G. Mestre (University of the Algarve)H-Index: 3
Last. Henrique L. Gomes (University of the Algarve)H-Index: 20
view all 9 authors...
Abstract Herein, we describe an electrophysiological based sensor that reproducibly monitors and quantifies in real-time collective migration and the formation of cell-cell junctions by C6 glioma cells seeded on top of electrodes. The signal amplitude and frequency generated by the migrating cells changed over time and these parameters were used to accurately calculate the migration speed. Electrophysiological measurements could also distinguish individual from collective cell migration. The mig...
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#1Youssef Elamine (University of the Algarve)H-Index: 3
#2Pedro M. C. Inácio (University of the Algarve)H-Index: 3
Last. Henrique L. Gomes (University of the Algarve)H-Index: 20
view all 7 authors...
Abstract An impedance based electronic tongue was developed and used to discriminate honey of different botanic origin. The e-tongue presented here is based on the small-signal frequency response of the electrical double-layer established between the honey solution and an array of four different sensing units composed by gold, carbon, indium-tin-oxide, and doped silicon. The ability of the e-tongue to discriminate honey of different floral origins was demonstrated by distinguishing honey from Bu...
2 CitationsSource
#1Joao Reis (UC: University of Coimbra)H-Index: 3
#2Maria C. R. Medeiros (UC: University of Coimbra)H-Index: 9
Last. Henrique L. Gomes (University of the Algarve)H-Index: 20
view all 6 authors...
The transient electrical behavior of an electrode/electrolyte interface based on an electrode micro-structured with gold protruding mushroom shapes is measured and modeled. The application of a voltage pulse train with changing frequency generates a corresponding train of current pulses with an offset current that approaches a saturation limit exponentially. The transient behavior of the electrical current was accurately reproduced using the Nernst-Planck-Poisson model and the geometric paramete...
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#1Sanaz Asgarifar (University of the Algarve)H-Index: 2
#2Pedro M. C. Inácio (University of the Algarve)H-Index: 3
Last. Henrique L. Gomes (University of the Algarve)H-Index: 20
view all 4 authors...
Conducting polymer electrodes based on poly(3,4-ethylenedioxythiophene doped with poly(styrenesulfonate) (PEDOT:PSS) are evaluated as transducers to record extracellular signals in cell populations. The performance of the polymer electrode is compared with a gold electrode. A small-signal impedance analysis shows that in the presence of an electrolyte, the polymer electrode establishes for frequencies below 100 Hz a higher capacitive electrical double layer at the electrode/electrolyte interface...
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#1Ana L. G. Mestre (University of the Algarve)H-Index: 3
#2Mónica Cerquido (University of Porto)H-Index: 2
Last. Henrique L. Gomes (University of the Algarve)H-Index: 20
view all 11 authors...
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 μV for a bandwidth of 12.5 Hz was achieved. To obtain this high sensitivity, large area (4 mm2) 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 capacita...
3 CitationsSource
#1Ana L. G. Mestre (University of the Algarve)H-Index: 3
#2Pedro M. C. Inácio (University of the Algarve)H-Index: 3
Last. Henrique L. Gomes (University of the Algarve)H-Index: 20
view all 11 authors...
Astrocytes are neural cells that exhibit functional electrical properties sensitive to neuronal activity and capable of modulating neurotransmission. Thus, electrophysiological recordings of astroglial activity are very attractive to study the dynamics of glial signaling. This contribution reports on the use of ultra-sensitive planar electrodes combined with low noise and low frequency amplifiers that enable the detection of extracellular signals produced by primary cultures of astrocytes isolat...
2 CitationsSource
#2Ana L. G. MestreH-Index: 3
Last. Henrique L. GomesH-Index: 20
view all 11 authors...
Conducting polymer electrodes based on poly (3, 4 ethylenedioxythiophene):polystyrene sulfonate were used to record electrophysiological signals from autonomous cardiac contractile cells present in embryoid bodies. Signal detection was carried out by measuring the displacement current across the polymer/electrolyte double-layer capacitance, and compared with voltage detection. While for relatively low capacitance electrodes, the voltage amplification provides higher signal quality, and for high ...
6 CitationsSource
#2Ana L. G. MestreH-Index: 3
Last. Henrique L. GomesH-Index: 20
view all 8 authors...
Conducting polymer electrodes based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) are used to record extracellular signals from autonomous cardiac contractile cells and glioma cell cultures. The performance of these conducting polymer electrodes is compared with Au electrodes. A small-signal impedance analysis shows that in the presence of an electrolyte, both Au and polymer electrodes establish high capacitive double-layers. However, the polymer/electrolyte interfacial r...
1 CitationsSource
#1Maria C. R. Medeiros (UC: University of Coimbra)H-Index: 9
#2Ana L. G. Mestre (University of the Algarve)H-Index: 3
Last. Henrique L. Gomes (University of the Algarve)H-Index: 20
view all 12 authors...
An electrical method to measure extracellular bioelectrical activity in vitro is presented. This method exploits the Helmholtz capacitive double-layer established at the electrode surface. Small extracellular voltage variations in the order of μVs induce through the double-layer capacitor a displacement current that is measured. This current is then enhanced by a gain factor proportional to the electrode capacitance. In addition, when measurements are carried out at low frequencies in current mo...
11 CitationsSource
Apr 11, 2016 in DoCEIS (Doctoral Conference on Computing, Electrical and Industrial Systems)
#1Sanaz Asgarifar (University of the Algarve)H-Index: 2
#2Henrique L. Gomes (University of the Algarve)H-Index: 20
Last. Pedro Alpuim (University of Minho)H-Index: 22
view all 9 authors...
This work presents an experimental characterization of electrochemically gated graphene field-effect transistors (EGFETs) to measure extracellular cell signals. The performance of the EGFETs was evaluated using cardiomyocytes cells. Extracellular signals with a peak value of 0.4 pico-amperes (pA) embedded in a noise level of 0.1 pA were recorded. Signals in current mode were compared with signals recorded as a voltage. Signals below 28 µV of magnitude can be detected in a noise floor of 7 µV wit...
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