Enzyme assays using sensor arrays based on ion-selective carbon nanotube field-effect transistors

In the fields of clinical diagnostics and point-of-care diagnosis as well as food and environmental monitoring there is a high demand for reliable high-throughput, rapid and highly sensitive assays for a simultaneous detection of several analytes in complex and low-volume samples. Sensor platforms b...

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Bibliographic Details
Published in:Biosensors & bioelectronics 2016-10, Vol.84, p.7-14
Main Authors: Melzer, K., Bhatt, V. Deep, Jaworska, E., Mittermeier, R., Maksymiuk, K., Michalska, A., Lugli, P.
Format: Article
Language:English
Subjects:
Array
Assaying
Biosensing Techniques - instrumentation
Carbon nanotubes
Electrolyte-gated CNT-FET
Enzyme Assays - instrumentation
Enzymes
Enzymes, Immobilized - chemistry
Enzymes, Immobilized - metabolism
Enzyme–substrate interactions
Equipment Design
Field effect transistors
Humans
Ion-selective CNT-FET
Nanotubes, Carbon - chemistry
Semiconductor devices
Sensor arrays
Sensors
Surface chemistry
Transistors, Electronic
Urea
Urea - analysis
Urea - metabolism
Urease - chemistry
Urease - metabolism
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Summary:In the fields of clinical diagnostics and point-of-care diagnosis as well as food and environmental monitoring there is a high demand for reliable high-throughput, rapid and highly sensitive assays for a simultaneous detection of several analytes in complex and low-volume samples. Sensor platforms based on solution-processable electrolyte-gated carbon nanotube field-effect transistors (CNT-FETs) are a simple and cost-effective alternative for conventional assays. In this work we demonstrate a selective as well as direct detection of the products of an enzyme-substrate interaction, here the for metabolic processes important urea-urease system, with sensors based on spray-coated CNT-FETs. The selective and direct detection is achieved by immobilizing the enzyme urease via certain surface functionalization techniques on the sensor surface and further modifying the active interfaces with polymeric ion-selective membranes as well as pH-sensitive layers. Thereby, we can avoid the generally applied approach for a field-effect based detection of enzyme reactions via detecting changes in the pH value due to an on-going enzymatic reaction and directly detect selectively the products of the enzymatic conversion. Thus, we can realize a buffering-capacity independent monitoring of changes in the substrate concentration. •Sensor array based on spray-coated electrolyte-gated CNT-FETs.•Immobilization of urease via certain surface functionalization techniques on sensor.•Sensor modification with polymeric ion-selective membranes.•Selective and direct detection of the products of an enzyme-substrate interaction.•Buffering-capacity independent monitoring of changes in the substrate concentration.
ISSN:0956-5663
1873-4235
DOI:10.1016/j.bios.2016.04.077