In Vivo Application of Isfets: Summary of Current Laboratory Research and Probable Future Clinical Detectors

McKinley, Bruce A.; Janata, Jiřı́; Houtchens, Bruce A.

doi:10.1016/b978-0-08-033201-7.50010-4

Cited by 26 publications

(18 citation statements)

References 6 publications

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“…Consequently, response of the ISFETs toward acids and C02 will vary considerably depending on the extent of the water in the layer and on which membrane components are controlling the initial pH of this layer. For example, hydrolysis of membrane plasticizers (e.g., phthalates) could yield trace levels of phthalic acid in this layer which would tend to make the initial pH of this region acidic (e.g., perhaps pH [4][5][6]. Similarly, as silicone rubber membranes cure, they liberate acetic acid which could be retained within this layer.…”

Section: Discussionmentioning

confidence: 99%

“…Recent literature and conference reports (4,12,13) regarding the performance of potassium ISFETs for continuous in vivo measurements have been contradictory. Some reports suggest that such devices are stable (12) while others clearly suggested significant drift problems (13).…”

Section: Discussionmentioning

confidence: 99%

“…Measurements were made in a constant current mode at 100 µ source-drain current. Thus, if the gate potential increases, the reference electrode potential decreases so as to maintain a constant source-drain current (4). The drain-source voltage (Yds) was maintained at 4.0 V. All measurements were made in conjunction with a separate double junction reference electrode in which the outer chamber was filled with 1 M NaNOs (NaN03 was used rather than equitransferent KN03 or KC1 so that leakage of K+ would not be a problem).…”

Section: Sectionmentioning

confidence: 99%

“…Band and co-workers have reported considerable success in preliminary animal studies with simple scaled down versions of conventional ion-exchanger or neutral carrier based polymer membrane type ISEs (with internal electrolyte solutions) (2,3). Others have described the fabrication and performance of ion-selective field effect transistors (ISFETs) which are, in effect, solid-state devices (no internal reference electrolyte) (4)(5)(6)(7)(8). The ISFET has attracted considerable attention because it is envisioned that a single miniaturized solid-state chip could contain multiple gates and be used to sense several ions simultaneously.…”

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confidence: 99%

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Response of ion-selective field effect transistors to carbon dioxide and organic acids

Fogt¹,

Untereker²,

Norenberg³

et al. 1985

Anal. Chem.

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1995excursion in the abundance of that isotope. The natural abundance of 34S is on the order of 4.0% and that of I5N is about 0.37%. It will, therefore, be possible to follow the dilution of 16N down to approximately a factor of 10 lower abundance than will be possible with Calculations based on these estimates suggest that 1 kg of %SO4 would label about 1 mile3 of air at the detection limit given a background level of about 8 pg/m3 sulfate. Sir:In recent years, the fabrication and study of various miniaturized versions of ion-selective electrodes (ISEs) have been vigorously pursued (1). Once fully developed, it is hoped that such electrochemical devices could be routinely used for continuous in vivo monitoring of blood electrolytes (e.g., Kt, Nat, C1-, etc.) during surgical procedures or at the bedside of patients in critical care units. Band and co-workers have reported considerable success in preliminary animal studies with simple scaled down versions of conventional ion-exchanger or neutral carrier based polymer membrane type ISEs (with internal electrolyte solutions) (2,3). Others have described the fabrication and performance of ion-selective field effect transistors (ISFETs) which are, in effect, solid-state devices (no internal reference electrolyte) (4-8). The ISFET has attracted considerable attention because it is envisioned that a single miniaturized solid-state chip could contain multiple gates and be used to sense several ions simultane-ISFETs which are not covered with polymeric ion-selective membranes can be used directly as pH sensors. The insulating gate materials are typically silicon nitride and silicon oxide which, by their own intrinsic surface properties, develop phase boundary potentials proportional to the logarithm of hydrogen ion activity of any solution they are in contact with. However, potassium ISFETs, for example, are usually prepared by coating the gate region of these pH devices with the same polymeric ion-selective membranes used in conventional potassium ISEs. Thus, once the gate region is covered with the polymeric membrane material, two potentials are generated: a Donnan potential at the interface of the membrane and the sample, dependent on the analyte ion activity in the sample, and an unknown potential at the interface of the membrane and the gate which is dependent on the activity of hydrogen ions present in this region. It is our belief that, since the hydrogen ion activity is not fixed at this membrane-gate interface, species which can enter this region by passing through the membrane can alter the pH and therefore interfere with the measurement of the analyte ions.In this correspondence, we provide preliminary data which strongly supports this view. Indeed, it is clearly shown that ously, ISFETs based on polymer ion-selective membranes are subject to positive interference by carbon dioxide and organic acids in the sample solution. As a model, we describe experimental results obtained with potassium ISFETs and nonselective ISFETs coated with polymer membranes containing...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Sectionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Response of ion-selective field effect transistors to carbon dioxide and organic acids

Fogt¹,

Untereker²,

Norenberg³

et al. 1985

Anal. Chem.

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“…Several approaches to the fabrication of multiple-analyte in vitro and in vivo sensors have been reported previously. Ion-selective field effect transistor (ISFET) devices have very small sensing areas, allowing a single miniaturized solid-state chip to be configured for simultaneous monitoring of several analytes (2,5). While the ISFET concept has generated considerable interest, fundamental problems regarding sensor encapsulation, drift, and interference from electrically neutral acidic sample species (e.g.…”

mentioning

confidence: 99%

Potentiometric combination ion-carbon dioxide sensors for in vitro and in vivo blood measurements

Collison¹,

Aebli²,

Petty³

et al. 1989

Anal. Chem.

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The development and analytical performance of a novel potentiometric combination ion/pCO2 sensor design for in vitro and in vivo measurements are reported. The design is based on incorporating an appropriate ionophore within the outer silicone gas permeable membranes of both conventional macro and new catheter-type pCO2 sensors. Simultaneous measurement of the potentials across the ion-selective/gas permeable membrane and the inner glass or polymer pH sensitive membrane provides the basis for continuous monitoring of both ionic and pCO2 levels with the same device. A macro-sized K+/pCO2 embodiment of the sensor is constructed from a commercial Severinghaus CO2 sensor and is used to demonstrate the principles and capabilities of the proposed design. A flexible, miniaturized (outer diameter = 1.2 mm) combination K+/pCO2 catheter sensor is also described. The catheter-type sensor is fabricated by inserting a tubular polymer membrane pH electrode into an outer silicone rubber tube doped with valinomycin. Continuous measurements of K+ and pCO2 during 6-h blood pump studies using both the macro and catheter-type combination sensors correlate well with those of conventional bench-top analyzers. In addition, continuous (4 h) intravascular measurements with the combination catheter sensor in dogs show good agreement with those of commercial blood analyzers (R = 0.984 and 0.962 for pCO2 and K+, respectively.

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Future Trends in Electrode Technology

Rooij

1987

Presurgical Evaluation of Epileptics

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In Vivo Application of Isfets: Summary of Current Laboratory Research and Probable Future Clinical Detectors

Cited by 26 publications

References 6 publications

Response of ion-selective field effect transistors to carbon dioxide and organic acids

Response of ion-selective field effect transistors to carbon dioxide and organic acids

Potentiometric combination ion-carbon dioxide sensors for in vitro and in vivo blood measurements

Future Trends in Electrode Technology

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