ROLDUCA
ISPAC20
ABBEY,KE
012,10–
ERKRADE,
PROGRAM
13JUNE
THENETH
M
HERLANDSS
Session 2: Polymers and Energy: The Characterization Challenge
CL-14
ENTRAPMENT OF TYROSINASE IN A REDOX POLYMER
Huseyin Bekir Yildiz, Jaime Castillo, Dmitrii A. Guschin, Wolfgang Schuhmann, Levent Toppare
1) Department of Chemistry, Karamanoglu Mehmetbey University 70100 Karaman, Turkey
2) MIC – Institut for Mikro- og Nanoteknologi DTU, Bygning 345Ø, DK-2800 Kgs. Lyngby, Denmark
3-4) Analytische Chemie – Elektroanalytik & Sensorik, Ruhr Universit€at Bochum, Universit€atsstrasse 150, D-44780 Bochum, Germany
5) Department of Chemistry, Middle East Technical University, TR-06531 Ankara, Turkey
Abstract
An amperometric biosensor for the detection of phenolic compounds was developed based on the immobilization of tyrosinase within an Os-complex functionalized electrodeposition polymer. Integration of tyrosinase within the redox polymer assures efficient catechol recycling between the enzyme and the polymer bound redox sites. The non-manual immobilization procedure improves the reproducibility of fabrication process, greatly reduces the desorption of the enzyme from the immobilization layer, and, most importantly prevents fast inactivation of the enzyme by its substrate due to fast redox cycling.
A two-layer sensor architecture was developed involving ascorbic acid oxidase entrapped within an electrodeposition polymer in a second layer on top of the redox polymer=tyrosinase layer. Using this
sensor architecture it was possible to eliminate the current interference arising from direct ascorbate oxidation up to a concentration of 630 mM ascorbic acid. The effects of the polymer thickness, the enzyme=polymer ratio, and the applied potential were evaluated with respect to optimal sensor properties. The sensitivity of the optimized sensors for catechol was 6.1 nA mM_1 with a detection limit of 10 nM, and for phenol 0.15 nA mM_1 with a detection limit of 100 nM.
