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Ana L. G. Mestre
University of the Algarve
ElectrophysiologyCapacitive sensingExtracellularCapacitanceElectrolyte
10Publications
3H-index
31Citations
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Publications 11
Newest
#2Rute C. Félix (University of the Algarve)H-Index: 10
Last. Deborah M. Power (University of the Algarve)H-Index: 45
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Abstract Cartilage acidic protein 1 (CRTAC1) is an extracellular matrix protein of human chondrogenic tissue that is also present in other vertebrates, none-vertebrate eukaryotes and in some prokaryotes. The function of CRTAC1 remains unknown but the protein’s structure indicates a role in cell-cell or cell-matrix interactions and calcium-binding. The aim of the present study was to evaluate the in vitro effects of hCRTAC1 on normal human dermal fibroblasts (NHDF). A battery of in vitro assays (...
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#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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#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
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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
#1Sanaz AsgarifarH-Index: 2
Last. Henrique L. GomesH-Index: 20
view all 8 authors...
#1Paulo R. F. Rocha (MPG: Max Planck Society)H-Index: 7
#2Maria C. R. Medeiros (UC: University of Coimbra)H-Index: 9
Last. Henrique L. Gomes (University of the Algarve)H-Index: 20
view all 13 authors...
Glioma patients often suffer from epileptic seizures because of the tumor’s impact on the brain physiology. Using the rat glioma cell line C6 as a model system, we performed long-term live recordings of the electrical activity of glioma populations in an ultrasensitive detection method. The transducer exploits large-area electrodes that maximize double-layer capacitance, thus increasing the sensitivity. This strategy allowed us to record glioma electrical activity. We show that although glioma c...
8 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
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