| Abstract [eng] |
The amperometric and voltammetric biosensors, based on gold nanoparticles, were designed and applied for biochemical, clinical and environment applications. Electrochemical biosensors are very selective, sensitive, fast and reusable. Gold, silver, platinum and SiO2 particles in the range 1–100 nm often provide an ideal remedy for immobilized enzymes with minimum diffusion limitations, promotion of electrochemical reaction, maximum surface area per mass unit and high effective achievement of enzymes direct wiring to electrode surface. Also, nanoparticles increase electron transfer rate between enzyme and an electrode surface. The aim of the work was to to apply different size nanoparticles, different glucose oxidases and electroconductive polymer polypyrrole for graphite electrode modification and determine the analytical characteristics of enzymatic biosensors for determination of glucose. It is established, that gold nanoparticles immobilized on graphite electrode with electron transfer mediator provide more effective electron transfer from glucose oxidase to electrode. Also, gold nanoparticles present in solution provide more effective electron transfer from enzyme to electrode when concentration of gold nanoparticles is ˂ 0.06 nmol/L and concentration of electron transfer mediator PMS is 2 mmol/L. The higher concentrations of nanoparticles in the solution make the electron transfer in the same system less efficient if compared with lower concentrations of nanoparticles. The limit of detection for glucose using GR/GOx/Ppy and GR/AuNPs13nm/GOx/Ppy electrodes after 3 h of chemical polymerisation was determined to be 0.07 mmol/L. Smaller AuNPs based systems exhibited higher amperometric responses at the same concentration of glucose before and after the formation of polypyrrole layer. Finally, the most effective enzyme for modification of biosensors for electrochemical determination of glucose is enzyme from Penicillium funiculosum. In this system the analytical responses are the highest and the stability is good. |
