| Abstract [eng] |
Enzymatic π-π-conjugated polymer synthesis method based on the glucose oxidase catalyzed oxidation of glucose and molecular oxygen to hydrogen peroxide and gluconolactone, which spontaneously hydrolyzes to gluconic acid reaction, was proposed in this work. Catalytic glucose oxidase activity was used for pyrrole and aniline polymerization. It is shown that the solution of glucose, oxygen and dissolved enzyme - catalyzed reaction that formed a strong oxidizing agent hydrogen peroxide and gluconic acid which allows the initiation of polymerization reaction process. Adapted polymer synthesis method demonstrated the possibility of polyaniline and polypyrrole layer to cover the glucose oxidase modified graphite electrode surface and synthesis of glucose oxidase and gold nanoparticles embedded in a layer of polyaniline nanocomposite structures. Key analytical characteristics of glucose biosensor modified by nanocomposite structures were analyzed and compared. In further studies it was shown that the polymeric layer covering the glucose oxidase modified graphite electrode surface can be change the immobilized enzyme kinetic properties and it is possible to construct biosensors capable of detecting glucose in a wider range. Application of colloidal gold derivatives demonstrated that gold nanoparticles not only increases the rate of polyaniline formation, but also being as a part of glucose oxidase and polyaniline nanocomposite structures shows some electron transfer mediators properties. This has a positive effect on electron transfer from the enzyme redox center to the electrode surface and improves the biosensor sensitivity. In order to improve electron transport, compared electron transfer mediators tetrathiafulvalene, phenazine methosulfate, 5,6-diamin-1,10-phenanthroline, tetrathiafulvalene - tetracyanoquinodimethane complex, methylene blue, toluidine blue and potassium ferrocyanide ability to transfer electrons from the glucose oxidase redox center to the graphite electrode surface. The most effective electron transfer mediators tetratiofulvaleno and tetratiofulvaleno-tetracianochinondimetano complex were used to construct reagentless amperometric glucose sensors. |
