Thin-film IrO pH microelectrode for microfluidic-based microsystems

Ges, Igor A.; Ivanov, B.; Schaffer, David K.; Lima, Eduardo A.; Werdich, Andreas A.; Baudenbacher, Franz

doi:10.1016/j.bios.2004.09.021

Cited by 118 publications

(112 citation statements)

References 41 publications

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“…In the considered range, the potential changes linearly with increasing pH, with a sensitivity of -74±3 mV/pH for the forward scan, and -75±5 mV/pH for the backward scan. Our sensor with the IrOx film showed a near super-Nernstian response with sensitivity values similar to the ones reported in [19].…”

Section: Ph Sensorsupporting

confidence: 85%

“…The drugs ETO, MTX and ETD purchased as a powder (Sigma-Aldrich) were dissolved in Dimethyl sulfoxide due to their low solubility in water. For the pH sensor, a solution of Iridium(IV) chloride hydrate (99.9% metals basis, from Sigma Aldrich), H 2 O 2 (30%), oxalic acid dihydrate (98%, from Sigma Aldrich), and potassium carbonate anhydrous (99%, from Alfa Aesar) was prepared for the deposition of the Iridium Oxide film (IrOx), as described in [19]. …”

Section: Methodsmentioning

confidence: 99%

“…IrOx is a well-known biocompatible material already used in the creation of implantable electrodes [19]. The OCP of an IrOx film changes in a predictable manner according to the pH of the solution.…”

Section: Ph Sensormentioning

confidence: 99%

See 2 more Smart Citations

Electrochemical biochip for applications to wireless and batteryless monitoring of free-moving mice

Baj-Rossi

Micheli

Carrara

2014

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Abstract-A multi-sensing platform for applications in wireless and batteryless monitoring of free-moving small animals is presented in this paper. The proposed platform hosts six sensors: four biosensors for sensing of both disease biomarkers and therapeutic compounds, and two further sensors (T and pH) for biosensor calibration. Electrodeposition of Multi-Walled Carbon Nanotubes (MWCNTs) and the subsequent functionalization with proper enzymes is used to assure sensitivity and specificity in electrochemical biosensing. The realized sensors are demonstrated to be capable of measuring several parameters: lactate with a sensitivity of 77±26 µA/mM· cm 2 and a limit of detection (LOD) of 4±1 µM; glucose with a sensitivity of 63±15 µA/mM· cm 2 and a LOD of 8±2 µM; Etoposide (a well known anti-cancer agent) with a sensitivity of 0.15±0.04 mA/mM· cm 2 and a LOD of 4±1 µM; Open Circuit Potential (OCP) measurements are used on a Pt/IrOx junction to sense pH with a sensitivity of around -75±5mV/pH; while a Pt resistive thermal device is used to measure physiological temperature-range with an average sensitivity of 0.108±0.001 kΩ/°C.

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Section: Ph Sensorsupporting

confidence: 85%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Electrochemical biochip for applications to wireless and batteryless monitoring of free-moving mice

Baj-Rossi

Micheli

Carrara

2014

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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show abstract

“…A detailed protocol to deposit the iridium oxide films onto the Pt-films and their properties was described in previous work (Ges et al, 2005(Ges et al, , 2007. The deposition solution was prepared based on the method proposed by Yamanaka (1989Yamanaka ( , 1991 and Marzouk et al (1998;Marzouk, 2003).…”

Section: Iro X Ph Sensitivity and Reference Electrodesmentioning

confidence: 99%

On-chip acidification rate measurements from single cardiac cells confined in sub-nanoliter volumes

Ges

Dzhura

Baudenbacher

2008

Biomed Microdevices

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The metabolic activity of cells can be monitored by measuring the pH in the extracellular environment. Microfabrication and microfluidic technologies allow the sensor size and the extracellular volumes to be comparable to single cells. A glass substrate with thin film pH sensitive IrO x electrodes was sealed to a replica-molded polydimethylsiloxane (PDMS) microfluidic network with integrated valves. The device, termed NanoPhysiometer, allows the trapping of single cardiac myocytes and the measurement of the pH in a detection volume of 0.36 nL. For wild-type (WT) single cardiac myocytes an acidification rate of 6.45 ± 0.38 mpH/min was measured in comparison to 19.5 ± 0.38 mpH/min for very long chain Acyl-CoA dehydrogenase (VLCAD) deficient mice in 0.8 mM of Ca 2+ . VLCAD deficiency is a fatty acid oxidation disease leading to cardiomyopathy and arrhythmias. The acidification rate increased to 11.96 ± 1.33 mpH/min for WT and to 32.0 ± 4.64 mpH/min for VLCAD −/− in 1.8 mM of Ca 2+ . The NanoPhysiometer concept can be extended to study ischemia/reperfusion injury or disorders of other biological systems to identify strategies for treatment and possible pharmacological targets.

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“…However, traditional glass electrodes have many disadvantages, such as high cost, mechanical fragility, difficult to miniaturize, need for wet storage, large size and limited shape. To overcome these drawbacks and further expand the application fields, alternative pH sensor structures based on ion-sensitive field effect transistor (ISFET) [7][8][9], solid state [10,11], hydrogel [12,13], and microelectrode [14,15], have been reported.…”

Section: Introductionmentioning

confidence: 99%

Recent Developments in R.F. Magnetron Sputtered Thin Films for pH Sensing Applications—An Overview

2014

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pH sensors are widely used in chemical and biological applications. Metal oxides-based pH sensors have many attractive features including insolubility, stability, mechanical strength, electrocatalyst and manufacturing technology. Various metal oxide thin films prepared by radio frequency (R.F.) magnetron sputtering have attractive features, including high pH sensitivity, fast response, high resolution, good stability and reversibility as well as potential for measuring pH under conditions that are not favourable for the commonly used glass electrodes-based pH sensors. In addition, thin film pH sensors prepared by R.F. magnetron sputtering offer many advantages, such as ease of packaging, low cost through the use of standard microfabrication processes, miniaturisation, capability of measuring pH at high temperatures, ruggedness and disposability. In this paper, recent development of R.F. magnetron sputtered thin films for pH sensing applications are reviewed.

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Thin-film IrO pH microelectrode for microfluidic-based microsystems

Cited by 118 publications

References 41 publications

Electrochemical biochip for applications to wireless and batteryless monitoring of free-moving mice

Electrochemical biochip for applications to wireless and batteryless monitoring of free-moving mice

On-chip acidification rate measurements from single cardiac cells confined in sub-nanoliter volumes

Recent Developments in R.F. Magnetron Sputtered Thin Films for pH Sensing Applications—An Overview

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