Fabrication of microelectrode arrays for in situ sensing of oxidation reduction potentials

Influence of Treatment Conditions on the Chemical Oxidative Activity of H2SO4/H2O2 Mixtures for Modulating the Topography of Titanium

“…ORP measurements have been used so far in many environmental applications such as in situ monitoring of the chlorination/dechlorination process [23] and recognition of oxidants/reductants [24] in wastewater, as well as in the observation of the cycle chemistry in power plants. [25] The outcome of these measurements is the overall potential of all the reactive electrochemical couples in the solution.…”

Fabrication of a needle-type pH sensor by selective electrodeposition

“…Since current application is necessary for electrodeposition, application of current to specific pads of a packaged sensor results in selective deposition of the IrOx film. Thus, this approach offers the ability to selectively deposit metallic films at the tips of specific needle sensors, paving the way to integration of the pH sensor with the previously described needle-type ORP 4,5 and DO 6,7 sensors. Taking this approach further, different metallic films may be deposited at the tips of different needle sensors, permitting future integration of the pH sensor with the recently described phosphate sensor based on the cobalt oxide sensing layer.…”

“…1,3 Microelectromechanical system (MEMS) technologies can offer many advantages to fabrication and integration of sensors, including reduced sensor complexity, increased reproducibility (and yield) of the fabrication process, and reduced costs due to batch fabrication. We recently applied MEMS technologies to the development of microelectrode arrays (MEAs) for measurement of the oxidation-reduction potential (ORP) 4,5 and dissolved oxygen (DO). 6,7 ORP is a measure of the solution potential and thus ORP MEA sensors are non-specific and measure the oxidized and reduced forms of all chemical species in the solution.…”

PtIr Microwire Bonding for Deep-Brain Microelectrode by Electroplating

“…(5)(6)(7) During the past decade, many and perhaps most types of implanted microelectrode structures and fabrication processes have been studied. (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) Regarding the deep-brain microelectrode for long-term recording/stimulation, all the materials used to make the microelectrode must be biocompatible, and Pt and Pt 90 Ir 10 alloy are the best materials for microelectrode films and microwires, respectively, because of their good biocompatibility and corrosion resistance and also because of the charge injection capacity of Pt and low impedance and good mechanical property of Pt 90 Ir 10 alloy. (5,21) As for the microelectrode, whether telemetry is used or not in the electrode system, communication between the implanted microelectrode and the outside stimulator must be carried out through a multichannel of interconnected microwires and a percutaneous connector.…”

“…The mechanical and electrical stabilities of the connection are critical to the performance of the microelectrode system. In the above-mentioned references, microwire bonding was also studied and carried out by ultrasonic bonding, (5,9) soldering, (13) gluing with conductive epoxy (14,20) or micromachining. (5) However, owing to the high hardness and melting points of Pt and Pt 90 Ir 10 , it is diffi cult to connect Pt 90 Ir 10 microwires to Pt thin fi lm using the above joining methods.…”