Electrochemical characterization of a single-walled carbon nanotube electrode for detection of glucose.
We developed glucose biosensing electrodes using single-walled carbon nanotube (SWCNT) films on flexible, transparent poly(ethylene terephthalate). The homogeneous SWCNT films were fabricated by a vacuum filtration method, and the averaged resistivity and transparency of the fabricated flexible SWCNT films were 400 Omega sq(-1) and 80%, respectively. The glucose sensing electrodes were constructed by encapsulating glucose oxidase (GOx) by Nafion binder into the SWCNT film, and the variation in current response as a function of enzyme loading amount, Nafion thickness were investigated. 30 mg mL(-1) GOx and 2% Nafion was optimal for the detection of glucose. When ferrocene monocarboxylic acid (FMCA) was introduced as diffusional electron mediator, the current responses toward glucose of the Nafion/GOx/SWCNT electrodes in glucose solution containing FMCA were dramatically improved, and the developed sensor was independent of oxygen. In the application of GOx immobilized SWCNT films for glucose detection, a linear electrical response was observed for concentrations ranging from 0.25 to 3.0 mM, and the detection limit and the sensitivity were assessed to be 97 microM and 9.32 microA mM(-1) cm(-2), respectively. Moreover, according to the Lineweaver-Burk plot, the apparent Michaelis-Menten constant was calculated to be 23.8 mM, and the current responses did not interfere with coexisting electroactive species, indicating that Nafion is an effective permselective polymer barrier.
Pham
Xuan-Hung
XH
Department of Bionano Engineering, Hanyang University, Ansan 426-791, South Korea.
Bui
Minh-Phuong Ngoc
MP
Li
Cheng Ai
CA
Han
Kwi Nam
KN
Kim
Jun Hee
JH
Won
Hoshik
H
Seong
Gi Hun
GH
D015374:Biosensing Techniques / Q000379:methods; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D005296:Ferrous Compounds; D005465:Fluorocarbon Polymers / Q000737:chemistry; D005947:Glucose / Q000032:analysis; D005949:Glucose Oxidase / Q000737:chemistry; D057230:Limit of Detection; D000075163:Metallocenes; D037742:Nanotubes, Carbon / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011093:Polyethylene Terephthalates
D004800:Enzymes, Immobilized; D005296:Ferrous Compounds; D005465:Fluorocarbon Polymers; D000075163:Metallocenes; D037742:Nanotubes, Carbon; D011093:Polyethylene Terephthalates; C032949:ferrocenecarboxylic acid; C040402:perfluorosulfonic acid; D011092:Polyethylene Glycols; D005949:Glucose Oxidase; D005947:Glucose