Razvoj plošnog elektrokemijskog biosenzora za laktat

master's thesis

• Title (english): Development of a planar electrochemical lactate biosensor
• Author: Ivana Obrovac
• Mentor: Petar Kassal (mentor)
• Committee member: Petar Kassal (predsjednik povjerenstva)
• Committee member: Jozefina Katić (član povjerenstva)
• Committee member: Matija Cvetnić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2024-09-26, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Jedna od aktualnih tema današnjice, kako u medicini tako i za sportsku primjenu, odnosi se na određivanje koncentracije laktata u krvi i znoju. U ovom radu naglasak je stavljen na razvoj elektrokemijskog biosenzora za laktat pri čemu se ispitivanje jedne od potencijalnih izvedbi provodilo na dvije elektrode: 3D disk elektrodi od staklastog ugljika - GCE (engl. Glassy Carbon Electrode) i plošnoj tiskanoj ugljikovoj elektrodi ED-S1PE-C2, Micrux Fluidic. Obje elektrode oslojavane su: slojem berlinskog modrila kao elektrokatalizatorom za redukciju vodikovog peroksida, enzimom laktat oksidazom kao katalizatorom za reakciju oksidacije laktata, te slojem kitozana čija je uloga bila da sigurno zadržava sloj enzima na elektrodnoj površini. Odziv pojedinačnih slojeva na elektrodama te odziv konačne, potpuno oslojene elektrode sa svim slojevima, ispitan je metodama cikličke voltametrije i kronoamperometrije. U potpunosti oslojena GC elektroda nije dala smislen odziv na laktat. Zbog neprovedene modifikacije kitozana 1 M NaOH i posljedično loše adhezije, sloj je prilikom prvog uranjanja skliznuo s elektrode. Potpuno oslojena plošna tiskana ugljikova elektroda s modificiranim slojem kitozana, ni u jednom slučaju tijekom snimanja cikličke voltametrije nije dala smislen odziv u ovisnosti o promjeni koncentracije laktata. Kronoamperometrijski odziv pokazao je uspješan odziv na laktat u koncentracijskom rasponu od 17 mM do 41 mM. Dobiveni odziv pokazao je vrlo lošu linearnost (R2 = 0,7706) i lošu osjetljivost
(-0,0572 μA/mM), što ukazuje da se vrijednost struje ne mijenja značajno s promjenom koncentracije laktata.

Abstract (english)

One of the main topics currently, both in medicine and sports applications, is the determination of lactate concentration in blood and sweat.This paper focuses on the development of an electrochemical biosensor for lactate, in which the testing of one potential design was conducted on two electrodes: a 3D glassy carbon disk electrode (GCE) and a screen-printed carbon electrode (ED-S1PE-C2, Micrux Fluidic). Both electrodes were coated with layers: a Prussian blue layer as an electrocatalyst for hydrogen peroxide reduction, lactate oxidase as a catalyst for the oxidation reaction of lactate, and a chitosan layer whose role was to securely retain the enzyme layer on the electrode surface. The response of individual layers on the electrodes, as well as the response of the final, fully coated electrode with all layers, was examined using cyclic voltammetry and chronoamperometry methods. The fully coated GC electrode did not provide a meaningful response to lactate. Due to the absence of chitosan modification with 1 M NaOH and consequently poor adhesion, the layer slid off the electrode during the first immersion. The fully coated screen-printed carbon electrode with the modified chitosan layer did not, in any case, provide a meaningful response in relation to the change in lactate concentration during cyclic voltammetry recordings. The chronoamperometric response showed a successful response to lactate in the concentration range of 17 mM to 41 mM. The obtained response showed very poor linearity (R2 = 0,7706) and poor sensitivity (-0,0572 μA/mM), indicating that the current value does not significantly change with the change in lactate concentration.

• Keywords: biosenzor; laktat; mliječna kiselina; amperometrija
• Keywords (english): biosensor; lactate; lactic acid; amperometry
• Language: croatian
• URN:NBN: urn:nbn:hr:149:075312
• Project: Number: UIP-2020-02-9139; Title: Fotonsko sinteriranje inkjet ispisanih elektrokemijskih senzora i biosenzora na plastičnim podlogama; Title: Photonic sintering for inkjet printed electrochemical sensors and biosensors on plastic substrates; Acronym: PrintEChemSens; Leader: Petar Kassal; Jurisdiction: Croatia; Funder: Hrvatska zaklada za znanost; Funding stream: Installation Research Projects
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Advanced materials and technologies; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra primijenjene kemije (sveučilišni/a magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-11-06 14:06:21