Low-cost, transparent, and flexible single-walled carbon nanotube nanocomposite based ion-sensitive field-effect transistors for pH/glucose sensing

• Published in: Biosensors & bioelectronics Vol. 25; no. 10; pp. 2259 - 2264
• Main Authors: Lee, Dongjin, Cui, Tianhong
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-06-2010; Elsevier
• Subjects: Biological and medical sciences; Biosensing Techniques - instrumentation; Biosensors; Biotechnology; Carbon nanotube; Elastic Modulus; Equipment Design; Equipment Failure Analysis; Flexible sensor; Fundamental and applied biological sciences. Psychology; Glucose - analysis; Glucose Oxidase - chemistry; Glucose sensor; Hydrogen-Ion Concentration; ISFET; Layer-by-layer self-assembly; Methods. Procedures. Technologies; Nanotechnology - instrumentation; Nanotubes, Carbon - chemistry; pH sensor; Reproducibility of Results; Sensitivity and Specificity; Transistors, Electronic; Various methods and equipments; Flexible sensor; Carbon nanotube; ISFET; Glucose sensor; pH sensor; Layer-by-layer self-assembly; Self assembly; Nanotube; Glucose; Carbon; Ionosensible field effect transistor; Detector; Flexible; Biosensor; pH; Nanocomposite
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2010.03.003

Low-cost, transparent, and flexible ion-sensitive field-effect transistors (ISFETs) are presented as pH and glucose sensors. Single-walled carbon nanotubes (SWCNTs) and poly(diallyldimethyammonium chloride, PDDA) are deposited by layer-by-layer (LbL) self-assembly between two metallic electrodes patterned on a polyethylene terephthalate substrate. The pH ISFETs are characterized based on the fact that the electronic conductance of SWCNTs nanocomposite is determined by molecular protonation/deprotonation of carboxylic groups on SWCNTs and by the external Ag/AgCl reference gate voltage. Glucose is detected by the local pH change in the vicinity of SWCNTs with the aid of glucose oxidase (GOx) enzyme. The glucose sensor shows a sensitivity of 18–45
μA/mM on a linear range of 2–10
mM. The apparent Michaelis–Menten constant is 14.2
mM, indicating a high affinity of LbL assembled GOx to glucose. The LbL self-assembly of nanomaterials and enzymes on the transparent and flexible substrate suggests various chemical and biological sensors suitable for
in vivo application.