Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2010;10(6):6115-27.
doi: 10.3390/s100606115. Epub 2010 Jun 21.

Development of an ion sensitive field effect transistor based urea biosensor with solid state reference systems

Kow-Ming Chang  1 , Chih-Tien Chang, Kun-Mou Chan
Affiliations

Development of an ion sensitive field effect transistor based urea biosensor with solid state reference systems

Kow-Ming Chang et al. Sensors (Basel). 2010.

Abstract

Ion sensitive field-effect transistor (ISFET) based urease biosensors with solid state reference systems for single-ended and two-ended differential readout electronics were investigated. The sensing membranes of the biosensors were fabricated with urease immobilized in a conducting polymer-based matrix. The responses of 12.9∼198.1 mV for the urea concentrations of 8∼240 mg/dL reveal that the activity of the enzyme was not significantly decreased. Biosensors combined with solid state reference systems were fabricated, and the evaluation results demonstrated the feasibility of miniaturization. For the differential system, the optimal transconductance match for biosensor and reference field-effect transistors (REFET) pair was determined through the modification of the membranes of the REFETs and enzyme field-effect transistors (EnFETs). The results show that the transconductance curve of polymer based REFET can match with that of the EnFET by adjusting the photoresist/Nafion™ ratio. The match of the transconductance curves for the differential pairs provides a wide dynamic operating measurement range. Accordingly, the miniaturized quasi-reference electrode (QRE)/REFET/EnFET combination with differential arrangement achieved similar urea response curves as those measured by a conventional large sized discrete sensor.

Keywords: biosensor; differential measurement; enzyme field-effect transistors (EnFETs); ion sensitive field-effect transistors (ISFETs); reference field-effect transistors (REFETs); transconductance-match.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
The schematic diagram of the typical common-mode differential circuit.
Figure 2.
Figure 2.
Schematic diagrams of (a) ISFET (b) EnFET and REFET.
Figure 3.
Figure 3.
Test structures: (a) single-ended (b) two-ended differential pairs.
Figure 4.
Figure 4.
The IDS-VGS and transconductance (gm) curves of ZrO2 gate ISFETs with and without Nafion™ coating.
Figure 5.
Figure 5.
Equivalent circuit of (a) ideally polarizable interface and (b) ideally nonpolarizable interface.
Figure 6.
Figure 6.
The urea responses of urease-EnFET with different ratio of urease entrapped dL in axis label.
Figure 7.
Figure 7.
(a) Urea response of the GRE/EnFET (b) Storage and repeatability performances of the GRE/EnFET dL in axis label.
Figure 7.
Figure 7.
(a) Urea response of the GRE/EnFET (b) Storage and repeatability performances of the GRE/EnFET dL in axis label.
Figure 8.
Figure 8.
The gm curves of ISFET, EnFET and REFETs.
Figure 9.
Figure 9.
Urea response of test structures of the GRE/EnFET, SRE/EnFET, GRE/EnFET/REFET, QRE/EnFET/REFET and SRE/REFET dL in axis label.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Covington A.K., Valdes-Perezgasga F., Weeks P.A., Brown A.H. pH ISFETs for intramyocardial pH monitoring in man. Analusis. 1993;21:43–46.
    1. Osaka T., Komaba S., Seyama M., Tanabe K. High-sensitivity urea sensor based on the composite film of electroinactive polypyrrole with polyion complex. Sens. Actuat. B-Chem. 1996;35–36:463–469.
    1. Pijanowska D.G., Torbicz W. pH-ISFET based urea biosensor. Sens. Actuat. B–Chem. 1997;44:370–376.
    1. Puig-Lleixa C., Jimenez C., Alonso J., Bartroli J. Polyurethane-acrylate photocurable polymeric membrane for ion-sensitive field-effect transistor based urea biosensors. Anal. Chimica Acta. 1999;389:179–188.
    1. Soldatkin A.P., Montoriol J., Sant W., Martelet C., Jaffrezic-Renault N. A novel urea sensitive biosensor with extended dynamic range based on recombinant urease and ISFETs. Biosens. Bioelectron. 2003;19:131–135. - PubMed

Publication types

LinkOut - more resources