Functionalization of a poly(amidoamine) dendrimer with ferrocenyls and its application to the construction of a reagentless enzyme electrode.
Poly(amidoamine) dendrimers having various degrees of modification with the redox-active ferrocenyls were prepared by controlling the molar ratio of ferrocenecarboxaldehyde to amine groups of dendrimers. By alternate layer-by-layer depositions of partial ferrocenyl-tethered dendrimers (Fc-D) with periodate-oxidized glucose oxidase (GOx) on a Au surface, an electrochemically and enzymatically active multilayered assembly of enzyme was constructed. The resulting GOx/Fc-D multilayer-associated electrodes were electrochemically analyzed, and the surface concentration of ferrocenyl groups, active enzyme coverage, and sensitivity were estimated. A 32% dendrimer modification level of surface amines to ferrocenyls was found to be an optimum in terms of enzyme-dendrimer network formation, electrochemical interconnectivity of ferrocenyls, and electrode sensitivity. With the prepared Fc(32%)-tethered dendrimers, mono- and multilayered GOx/Fc-D electrodes were constructed, and their electrochemical and catalytic properties were characterized. The bioelectrocatalytic signals from the multilayered GOx/Fc-D electrodes were shown to be directly correlated to the number of deposited bilayers. From this result, it seems that the electrode sensitivity is directly controllable, and the multilayer-forming strategy with partial ferrocenyl-tethered dendrimers is useful for the construction of reagentless biosensors.
Yoon
H C
HC
Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Taejon, Korea.
Hong
M Y
MY
Kim
H S
HS
D015374:Biosensing Techniques; D004563:Electrochemistry; D004566:Electrodes; D004800:Enzymes, Immobilized; D005296:Ferrous Compounds / Q000737:chemistry*; D005947:Glucose / Q000032:analysis; D007202:Indicators and Reagents; D011073:Polyamines / Q000737:chemistry*
D004800:Enzymes, Immobilized; D005296:Ferrous Compounds; D007202:Indicators and Reagents; D011073:Polyamines; D005947:Glucose