Highly stable enzyme precipitate coatings and their electrochemical applications.
This paper describes highly stable enzyme precipitate coatings (EPCs) on electrospun polymer nanofibers and carbon nanotubes (CNTs), and their potential applications in the development of highly sensitive biosensors and high-powered biofuel cells. EPCs of glucose oxidase (GOx) were prepared by precipitating GOx molecules in the presence of ammonium sulfate, then cross-linking the precipitated GOx aggregates on covalently attached enzyme molecules on the surface of nanomaterials. EPCs-GOx not only improved enzyme loading, but also retained high enzyme stability. For example, EPC-GOx on CNTs showed a 50 times higher activity per unit weight of CNTs than the conventional approach of covalent attachment, and its initial activity was maintained with negligible loss for 200 days. EPC-GOx on CNTs was entrapped by Nafion to prepare enzyme electrodes for glucose sensors and biofuel cells. The EPC-GOx electrode showed a higher sensitivity and a lower detection limit than an electrode prepared with covalently attached GOx (CA-GOx). The CA-GOx electrode showed an 80% drop in sensitivity after thermal treatment at 50°C for 4 h, while the EPC-GOx electrode maintained its high sensitivity with negligible decrease under the same conditions. The use of EPC-GOx as the anode of a biofuel cell improved the power density, which was also stable even after thermal treatment of the enzyme anode at 50°C. The excellent stability of the EPC-GOx electrode together with its high current output create new potential for the practical applications of enzyme-based glucose sensors and biofuel cells.
Kim
Byoung Chan
BC
Environment Division, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea.
Zhao
Xueyan
X
Ahn
Hye-Kyung
HK
Kim
Jae Hyun
JH
Lee
Hye-Jin
HJ
Kim
Kyung Woo
KW
Nair
Sujith
S
Hsiao
Erik
E
Jia
Hongfei
H
Oh
Min-Kyu
MK
Sang
Byoung In
BI
Kim
Beom-Soo
BS
Kim
Seong H
SH
Kwon
Yongchai
Y
Ha
Su
S
Gu
Man Bock
MB
Wang
Ping
P
Kim
Jungbae
J
D015374:Biosensing Techniques / Q000295:instrumentation*; D011232:Chemical Precipitation; D003217:Conductometry / Q000295:instrumentation*; D004566:Electrodes; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005947:Glucose / Q000032:analysis* / Q000737:chemistry; D005949:Glucose Oxidase / Q000737:chemistry*
D004800:Enzymes, Immobilized; D005949:Glucose Oxidase; D005947:Glucose