Functionalization of a poly(amidoamine) dendrimer with ferrocenyls and its application to the construction of a reagentless enzyme electrode

Anal Chem. 2000 Sep 15;72(18):4420-7. doi: 10.1021/ac0003044.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biosensing Techniques*
  • Electrochemistry
  • Electrodes
  • Enzymes, Immobilized*
  • Ferrous Compounds / chemistry*
  • Glucose / analysis
  • Indicators and Reagents
  • Polyamines / chemistry*

Substances

  • Enzymes, Immobilized
  • Ferrous Compounds
  • Indicators and Reagents
  • Polyamines
  • Glucose