Glucose fast-response amperometric sensor based on glucose oxidase immobilized in an electropolymerized poly(o-phenylenediamine) film

Abstract

o-Phenylenediamine has been used for glucose oxidase (GOx) immobilization on Pt electrodes by electrochemical polymerization at +0.65 V vs SCE. By this approach the enzyme is entrapped in a strongly adherent, highly reproducible thin membrane, whose thickness is around 10 nm. This one-step procedure produces a glucose sensor with a response time less than 1 s, an active enzyme loading higher than 3 units/cm2 of electrode surface, a high sensitivity, and a sufficiently wide linear range. The glucose response shows an apparent Michaelis-Menten constant, K'm = 14.2 mM, and a limiting current density, jmax of 181 microA/cm2. The product kD of partition and diffusion coefficients of glucose in the polymer film is on the order of 10(-13) cm2/s. Due to permselectivity characteristics of the membrane, the access of ascorbate, a common interfering species, to the electrode surface is blocked. To our knowledge, this represents the first report of a membrane capable, at the same time, of immobilizing GOx and rejecting ascorbate. The interesting electrode behavior can be rationalized by using an existing model predicting the amperometric response of an immobilized GOx system.

Biosensor for Neurotransmitter L-Glutamic Acid Designed for Efficient Use of L-Glutamate Oxidase and Effective Rejection of Interference

“…2), i.e., similar to Pt/PPD/GOx electrodes [33][34][35][36][37][38][39] but much faster than sensors incorporating PEA by the drop coating technique. 45 The sensitivity was high in the linear range (0-100 mmol l 21 Glu, 3.8 ± 1.3 nA cm 22 mmol 21 l, r 2 = 0.99 ± 0.01, n = 4) with a low LOD (2 3 s of baseline, see Table 1).…”

“…17,24 The classical procedure for incorporating oxidase enzymes into a protecting polymer film has been to co-deposit the enzyme and polymer onto the electrode from a solution of the enzyme and monomer. [33][34][35][36][37][38][39] This is convenient and effective but is very cost-inefficient for expensive enzymes such as GluOx. The aim of this work was to develop a more efficient procedure for producing Pt/ PPD/GluOx sensors with high sensitivity to Glu.…”

Contributions by a Novel Edge Effect to the Permselectivity of an Electrosynthesized Polymer for Microbiosensor Applications

“…Pt F /PEI/GluOx/PPD biosensors, incorporating the enzyme GluOx and sensitivity-boosting polycation PEI, 31,42,46,96 were therefore fabricated and calibrated in vitro for Glu, H 2 O 2 , and AA. The sensitivity to Glu in the linear response region of the Michaelis-Menten calibration curve was high (62 ± 8 µA cm -2 mM -1 , n ) 14), representing 24 ± 4% of the sensitivity of the same biosensors in H 2 O 2 calibrations performed under the same quiescent conditions, and reflecting efficient enzyme kinetics in these ultrathin insulating PPD coatings (<30 nm [56][57][58][59][60] 14%, n ) 14) and P(AA)% (0.20 ± 0.04%, n ) 14) indicate that the dip-evaporation deposition of both PEI and GluOx on the bare Pt F before PPD electrosynthesis only marginally affected the ability of the composite polymer matrix to reject AA interference or to enable efficient H 2 O 2 transport to the metal surface. Not surprisingly, as a result of incorporating these two macromolecular species into the PPD matrix, its permeability increased, but by only a factor of 2 for both parameters (see Figures 4 and 5), minimizing the effects on selectivity.…”

An amperometric glucose-oxidase/poly(o-phenylenediamine) biosensor for monitoring brain extracellular glucose: in vivo characterisation in the striatum of freely-moving rats

“…Recently, the groups of Zambonin (Malitesta et al, 1990) and Yacynych (Sasso et al, 1990) have reported H 2 O 2 -detecting biosensors based on the immobilisation of GOx in electropolymerized poly(phenylenediamine) films on Pt electrodes with properties (e.g. interferencefree, high enzyme activity and low response time) indicating ideal suitability for detecting substrates in biological fluids.…”