Dvoenzimski amperometrijski senzor za piruvat s piruvat-oksidazom imobiliziranima u vodljivom sol-gel kompozitu

master's thesis

• Title (english): Bienzyme amperometric sensor for the pyruvate with the pyruvate oxidase and peroxidase immobilized in conductive sol-gel composite
• Author: Lidija Gnječ
• Mentor: Damir Iveković (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Chemistry and Biochemistry); (Laboratory for General and Inorganic Chemistry and Electroanalysis); Zagreb
• Defense date and country: 2012-12-21, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Biosenzori su kemijski senzori kod kojih je za selektivno i osjetljivo prepoznavanje analita odgovorna neka biološka vrsta, najčešće enzim. Jedan od važnih analita, za čijim određivanjem potreba postoji u medicinskoj dijagnostici te u kontroli različitih fermentativnih procesa, jest pirogrožđana kiselina, odnosno piruvat. Cilj ovog rada je bio konstruirati amperometrijski biosenzor za osjetljivo i selektivno određivanje malih koncentracija piruvata u kompleksnim uzorcima. U tu je svrhu načinjen biosenzor s piruvatom oksidazom, a vodikov peroksid koji nastaje kao produkt katalizirane oksidacije piruvata detektirao se pomoću amperometrijskog pretvornika temeljenog na peroksidazi imobiliziranoj na titanatne nanocjevčice, čime se dodatno povećala selektivnost biosenzora. Određeni su optimalni parametri rada biosenzora, kao što su optimalni pH i sastav pufera, optimalna koncentracija fosfata, tiamin pirofosfata (TPP) i flavin adenin dinukleotida (FAD) u osnovnom elektrolitu, te uvjeti skladištenja biosenzora. Pri optimalnim radnim uvjetima biosenzora, linearni odziv na piruvat postignut je u području koncentracija do 80 µmol/L, uz limit detekcije od 1,2 µmol/L i osjetljivost od 13,0 mA dm3mol-1cm-2.

Abstract (english)

Biosensors are chemical sensors in which selective and sensitive recognition of analyte is provided by some biological component, e.g. enzyme. One of the most important analyte is pyruvate or piruvic acid whose detection is necessary in medical diagnostics and in the control of different fermentative processes. The objective of this graduate thesis was to design the amperometric biosensor for the sensitive and selective detection of small pyruvate concentrations in different complex samples. For this purpose biosensor with pyruvate oxidase was designed. Hydrogen peroxide produced in the catalized oxidation of pyruvate was detected by the amperometric tranducer based on the peroxidase immobilized on the titanate nanotubes, which enhanced the biosensor selectivity. The optimal biosensor operating parameters were determined, like optimal pH value and buffer composition, optimal phosphate, thiamine pyrophosphate and flavin adenine dinucleotide concentration in base electrolyte and biosensor storage conditions. In optimal biosensor operating conditions pyruvate linear response was achieved in the concentration range up to 80 µmol/L, with the detection limit of 1,2 µmol/L and the sensitivity of 13,0 mA dm3mol-1cm-2.

• Keywords: biosenzori; piruvat; piruvat oksidaza; titanatne nanocjevčice
• Keywords (english): biosensor; pyruvate; pyruvate oxidase; titanate nanotubes
• Language: croatian
• URN:NBN: urn:nbn:hr:159:277266
• Study programme: Title: Biotechnology; specializations in: Biochemical Engineering; Course: Biochemical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo (diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-17 12:26:27