PMID- 30889834
OWN - NLM
STAT- MEDLINE
DCOM- 20190711
LR  - 20200225
IS  - 2079-6374 (Electronic)
IS  - 2079-6374 (Linking)
VI  - 9
IP  - 1
DP  - 2019 Mar 18
TI  - Continuous Monitoring of pH and Blood Gases Using Ion-Sensitive and Gas-Sensitive 
      Field Effect Transistors Operating in the Amperometric Mode in Presence of Drift.
LID - 10.3390/bios9010044 [doi]
LID - 44
AB  - Accurate and cost-effective integrated sensor systems for continuous monitoring 
      of pH and blood gases continue to be in high demand. The capacity of 
      ion-selective and Gas-sensitive field effect transistors (FETs) to serve as 
      low-power sensors for accurate continuous monitoring of pH and blood gases is 
      evaluated in the amperometric or current mode of operation. A stand-alone 
      current-mode topology is employed in which a constant bias is applied to the gate 
      with the drain current serving as the measuring signal. Compared with 
      voltage-mode operation (e.g., in the feedback mode in ion-selective FETs), 
      current-mode topologies offer the advantages of small size and low power 
      consumption. However, the ion-selective FET (ISFET) and the Gas-sensitive FET 
      (GasFET) exhibit a similar drift behavior, imposing a serious limitation on the 
      accuracy of these sensors for continuous monitoring applications irrespective of 
      the mode of operation. Given the slow temporal variation associated with the 
      drift characteristics in both devices, a common post-processing technique that 
      involves monitoring the variation of the drain current over short intervals of 
      time can potentially allow extraction of the measuring signal in presence of 
      drift in both sensor types. Furthermore, in the amperometric mode the static 
      sensitivity of a FET-based sensor, given by the product of the FET 
      transconductance and the sensitivity of the device threshold voltage to the 
      measurand concentration, can be increased by adjusting the device design 
      parameters. Increasing the sensitivity, while of interest in its own right, also 
      enhances the accuracy of the proposed method. Rigorous analytical validation of 
      the method is presented for GasFET operation in the amperometric mode. Moreover, 
      the correction algorithm is verified experimentally using a Si(3)N(4)-gate ISFET 
      operating in the amperometric mode to monitor pH variations ranging from 3.5 to 
      10.
FAU - Jamasb, Shahriar
AU  - Jamasb S
AD  - Department of Biomedical Engineering, Hamedan University of Technology, Hamedan 
      65169-13733, Iran. jamasb@hut.ac.ir.
LA  - eng
GR  - No. 18/96/1/590/Hamedan University of Technology/
PT  - Journal Article
DEP - 20190318
PL  - Switzerland
TA  - Biosensors (Basel)
JT  - Biosensors
JID - 101609191
RN  - 0 (Acids)
RN  - 0 (Gases)
SB  - IM
MH  - Acids/blood
MH  - *Algorithms
MH  - Biosensing Techniques/*methods/standards
MH  - Blood Gas Analysis/methods/standards
MH  - Gases/blood
MH  - Humans
MH  - Transistors, Electronic/standards
PMC - PMC6468803
OTO - NOTNLM
OT  - GasFET
OT  - ISFET
OT  - Instability
OT  - amperometric
OT  - continuous monitoring
OT  - current mode
OT  - drift
OT  - pH
COIS- The author declares no conflict of interest.
EDAT- 2019/03/21 06:00
MHDA- 2019/07/12 06:00
PMCR- 2019/03/01
CRDT- 2019/03/21 06:00
PHST- 2018/12/31 00:00 [received]
PHST- 2019/02/24 00:00 [revised]
PHST- 2019/03/04 00:00 [accepted]
PHST- 2019/03/21 06:00 [entrez]
PHST- 2019/03/21 06:00 [pubmed]
PHST- 2019/07/12 06:00 [medline]
PHST- 2019/03/01 00:00 [pmc-release]
AID - bios9010044 [pii]
AID - biosensors-09-00044 [pii]
AID - 10.3390/bios9010044 [doi]
PST - epublish
SO  - Biosensors (Basel). 2019 Mar 18;9(1):44. doi: 10.3390/bios9010044.