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Miniaturized integrated platform for electrical and optical monitoring of cell cultures.

Moldovan C, Iosub R, Codreanu C, Firtat B, Necula D, Brasoveanu C, Stan I - Sensors (Basel) (2012)

Bottom Line: Ten platinum electrodes and five sensors are placed on the shank and are connected with the external electronics through the pads.The electrodes are bidirectional and can be used both for electrical potential recording and stimulation of cells.The fabrication steps are presented, along with the electrical and optical characterization of the system.

View Article: PubMed Central - PubMed

Affiliation: National Institute for Research and Development in Microtechnologies, 126 Erou Iancu Nicolae, Bucharest 077190, Romania. carmen.moldovan@imt.ro

ABSTRACT
The following paper describes the design and functions of a miniaturized integrated platform for optical and electrical monitoring of cell cultures and the necessary steps in the fabrication and testing of a silicon microchip Micro ElectroMechanical Systems (MEMS)-based technology for cell data recording, monitoring and stimulation. The silicon microchip consists of a MEMS machined device containing a shank of 240 μm width, 3 mm long and 50 μm thick and an enlarged area of 5 mm × 5 mm hosting the pads for electrical connections. Ten platinum electrodes and five sensors are placed on the shank and are connected with the external electronics through the pads. The sensors aim to monitor the pH, the temperature and the impedance of the cell culture. The electrodes are bidirectional and can be used both for electrical potential recording and stimulation of cells. The fabrication steps are presented, along with the electrical and optical characterization of the system. The target of the research is to develop a new and reconfigurable platform according to the particular applications needs, as a tool for the biologist, chemists and medical doctors working is the field of cell culture monitoring in terms of growth, maintenance conditions, reaction to electrical or chemical stimulation (drugs, toxicants, etc.). HaCaT (Immortalised Human Keratinocyte) cell culture has been used for demonstration purposes in order to provide information on the platform electrical and optical functions.

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SEM pictures of the polyaniline conductive layer deposited on Ti/Pt electrode. (a) the nanofibers aspect of the polyaniline; (b) large area and porous aspect of 25 microns thick polyaniline.
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f5-sensors-12-11372: SEM pictures of the polyaniline conductive layer deposited on Ti/Pt electrode. (a) the nanofibers aspect of the polyaniline; (b) large area and porous aspect of 25 microns thick polyaniline.

Mentions: The reference electrode (Ag/AgCl, KCl 3 M) is a silver wire inserted into a small PDMS cavity filled with AgCl/KCl 3M. The sensor measurement is a voltage measurement at zero current. The instrument has an input resistance higher than 1 GΩ. The voltage is measured between two electrodes: the active electrode and the reference electrode. The measurement cell is calibrated individually based on the pair of values: voltage and pH. Two pH working electrodes are placed on the microprobe shank (Figure 3(B)). The pH working electrodes are integrated and planar. The pH working electrode of the pH sensor is a solid state sensor based on a conductive polymer, deposited on a platinum patterned microelectrode, developed on a silicon silicon wafer with thermal SiO2 on top, followed by a lift–off process for patterning the Ti/Pt metallic layer of the electrodes. The Ti/Pt electrode is covered by Si3N4 which is patterned by optical lithography followed by RIE etching of Si3N4 leaving openings where the polyaniline polymer is needed to be deposited [Figure 2(c)]. The next step is the electrochemical deposition of polyaniline conductive emeraldine base form on top of Ti/Pt. The working electrode is formed by Ti/Pt with conductive polyaniline on it. The electrochemically deposited polyaniline has an intrinsic nanofibre structure of 100 nm diameter, as we can see in Figure 5(a) [12].


Miniaturized integrated platform for electrical and optical monitoring of cell cultures.

Moldovan C, Iosub R, Codreanu C, Firtat B, Necula D, Brasoveanu C, Stan I - Sensors (Basel) (2012)

SEM pictures of the polyaniline conductive layer deposited on Ti/Pt electrode. (a) the nanofibers aspect of the polyaniline; (b) large area and porous aspect of 25 microns thick polyaniline.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472889&req=5

f5-sensors-12-11372: SEM pictures of the polyaniline conductive layer deposited on Ti/Pt electrode. (a) the nanofibers aspect of the polyaniline; (b) large area and porous aspect of 25 microns thick polyaniline.
Mentions: The reference electrode (Ag/AgCl, KCl 3 M) is a silver wire inserted into a small PDMS cavity filled with AgCl/KCl 3M. The sensor measurement is a voltage measurement at zero current. The instrument has an input resistance higher than 1 GΩ. The voltage is measured between two electrodes: the active electrode and the reference electrode. The measurement cell is calibrated individually based on the pair of values: voltage and pH. Two pH working electrodes are placed on the microprobe shank (Figure 3(B)). The pH working electrodes are integrated and planar. The pH working electrode of the pH sensor is a solid state sensor based on a conductive polymer, deposited on a platinum patterned microelectrode, developed on a silicon silicon wafer with thermal SiO2 on top, followed by a lift–off process for patterning the Ti/Pt metallic layer of the electrodes. The Ti/Pt electrode is covered by Si3N4 which is patterned by optical lithography followed by RIE etching of Si3N4 leaving openings where the polyaniline polymer is needed to be deposited [Figure 2(c)]. The next step is the electrochemical deposition of polyaniline conductive emeraldine base form on top of Ti/Pt. The working electrode is formed by Ti/Pt with conductive polyaniline on it. The electrochemically deposited polyaniline has an intrinsic nanofibre structure of 100 nm diameter, as we can see in Figure 5(a) [12].

Bottom Line: Ten platinum electrodes and five sensors are placed on the shank and are connected with the external electronics through the pads.The electrodes are bidirectional and can be used both for electrical potential recording and stimulation of cells.The fabrication steps are presented, along with the electrical and optical characterization of the system.

View Article: PubMed Central - PubMed

Affiliation: National Institute for Research and Development in Microtechnologies, 126 Erou Iancu Nicolae, Bucharest 077190, Romania. carmen.moldovan@imt.ro

ABSTRACT
The following paper describes the design and functions of a miniaturized integrated platform for optical and electrical monitoring of cell cultures and the necessary steps in the fabrication and testing of a silicon microchip Micro ElectroMechanical Systems (MEMS)-based technology for cell data recording, monitoring and stimulation. The silicon microchip consists of a MEMS machined device containing a shank of 240 μm width, 3 mm long and 50 μm thick and an enlarged area of 5 mm × 5 mm hosting the pads for electrical connections. Ten platinum electrodes and five sensors are placed on the shank and are connected with the external electronics through the pads. The sensors aim to monitor the pH, the temperature and the impedance of the cell culture. The electrodes are bidirectional and can be used both for electrical potential recording and stimulation of cells. The fabrication steps are presented, along with the electrical and optical characterization of the system. The target of the research is to develop a new and reconfigurable platform according to the particular applications needs, as a tool for the biologist, chemists and medical doctors working is the field of cell culture monitoring in terms of growth, maintenance conditions, reaction to electrical or chemical stimulation (drugs, toxicants, etc.). HaCaT (Immortalised Human Keratinocyte) cell culture has been used for demonstration purposes in order to provide information on the platform electrical and optical functions.

Show MeSH
Related in: MedlinePlus