Improved platinization conditions produce a 60-fold increase in sensitivity of amperometric biosensors using glucose oxidase immobilized in poly-o-phenylenediamine

Oxygen tolerance of an implantable polymer/enzyme composite glutamate biosensor displaying polycation-enhanced substrate sensitivity

“…Thus, PEI did not significantly affect the interaction of Glu with GluOx when the enzyme molecules were widely separated (zero loading limit). This finding provides additional evidence that the effect of PEI is not mediated by diffusion effects through the PEI/GluOx/PPD matrix (see Section 3.1), and is consistent with our 'ultra-thin layer' enzyme kinetic analysis (De Corcuera et al, 2005).…”

“…These results are consistent with the greater LRS of the PEI-containing devices (Table 1) coupled with little or no increase in baseline noise, and contrasts with other sensitivity-boosting strategies, such as platinization (De Corcuera et al, 2005), that have little effect on limits of detection due to significant increase in baseline fluctuations.…”

“…These complex analyses are often needed to understand and opti-mize the behavior of thick and/or conducting layers (Gooding et al, 1998;Baronas et al, 2003). However, a recent study has shown that substrate diffusion is not limiting for PPD layers incorporating enzyme (De Corcuera et al, 2005), due to their relatively small thickness (Gooding et al, 1998). Therefore, the basic Michaelis-Menten enzyme parameters used here provide more readily accessible insights into factors affecting the responsiveness of biosensors fabricated from ultra-thin (10-30 nm; Malitesta et al, 1990;Sohn et al, 1991;Myler et al, 1997;Craig and O'Neill, 2003) insulating PPD, and avoids the use of more complex analyses, such as those involving the Thiele modulus (Gooding and Hall, 1996).…”

Electrochemical quartz crystal impedance study on immobilization of glucose oxidase in a polymer grown from dopamine oxidation at an Au electrode for glucose sensing

“…Consequently, the new immobilization matrix is strongly recommended for immobilization of many other enzymes. Although the PFDO has been suggested as a GODimmobilization matrix better than commonly used PoAP and PNMP, we speculate that it is very interesting to further increase the effective activity of immobilized GOD and the glucosedetection sensitivity using platinization [43], or other protocols. Such researches are in progress in this laboratory based on the new quantitative gauges of ESA and ERA.…”

Designing sensitive and selective polymer/enzyme composite biosensors for brain monitoring in vivo

“…These complex analyses are often needed to understand and to optimize the behavior of thick and/or conducting layers [87]. However, a recent study has shown that substrate diffusion is not limiting for PPD layers incorporating enzymes [88], due to their ultrathin nature (10-30 nm [69,72,74]). The basic MichaelisMenten enzyme parameters used here therefore provide more readily accessible insights into factors affecting the responsiveness of biosensors fabricated from the insulating form of PPD, and avoid the use of more complex analyses, such as those involving the Thiele modulus [89].…”