Adsorption of glucose oxidase onto single-walled carbon nanotubes and its application in layer-by-layer biosensors.
In this study, we describe the use of a sodium cholate suspension-dialysis method to adsorb the redox enzyme glucose oxidase (GOX) onto single-walled carbon nanotubes (SWNT). By this method, solutions of dispersed and debundled SWNTs were prepared that remained stable for 30 days and which retained 75% of the native enzymatic activity. We also demonstrate that GOX-SWNT conjugates can be assembled into amperometric biosensors with a poly[(vinylpyridine)Os(bipyridyl)2Cl(2+/3+)] redox polymer (PVP-Os) through a layer-by-layer (LBL) self-assembly process. Incorporation of SWNT-enzyme conjugates into the LBL films resulted in current densities as high as 440 microA/cm2, which were a 2-fold increase over the response of films without SWNTs. We also demonstrate that the adsorption pH of the redox polymer solution and the dispersion quality of SWNTs were important parameters in controlling the electrochemical and enzymatic properties of the LBL films.
Carbon Nanotube Technology Center, University of Oklahoma, 100 East Boyd, Norman, Oklahoma 73019, USA.
Ta-Wei
TW
Tsai
Gustavo
G
Heckert
Luís F
LF
Neves
Yongqiang
Y
Tan
Der-You
DY
Kao
Roger G
RG
Harrison
Daniel E
DE
Resasco
David W
DW
Schmidtke
D000327:Adsorption; D015374:Biosensing Techniques / Q000379:methods*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005949:Glucose Oxidase / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry
D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D011108:Polymers; D005949:Glucose Oxidase