DEVELOPMENT OF NEW BIOSENSOR SYSTEMS BASED ON DITHIOL/GOLD NANOPARTICLE/3-MERCAPTO PROPIONIC ACID MODIFICATION FOR SPECIFIC AND SENSITIVE DETERMINATION OF GLYCEROL-3-PHOSPHATE
Project no. 662 · Status: Kapanmış · 2016
Summary
In this thesis, dithiol/gold nanoparticle/3-mercapto propionic acid modified glycerol-3-phosphate oxidase biosensor which brings a new and original perspective to biosensor technology was developed for the determination of glycerol-3-phosphate. In the biosensor preparetion, first self-assembled monolayer was formed in the presence of 1,4-butanedithiol onto gold electrode. The surface of the 1,4-butanedithiol modified electrode was covered with gold nanoparticle; then modified electrode was immersed into 3-mercapto propionic acid solution and glycerol-3-phosphate oxidase was immobilized on to the electrode surface. Glycerol-3-phosphate measurements with enzyme biosensor was performed between -0,1 V & +0,6 V potential with differential pulse voltammetry. Principle of measurements were implemented with the relation of the differention of oxidation peaks which caused by the linear relation between K3[Fe(CN)6] and glycerol-3-phosphate concentration. In the optimization of the developed biosensor some experiment were made about the bioactive layer components of the biosensor. At the end of the experiments; optimum enzyme amount, duration of SAM formation, AuNP and 3-mercaptopropionic acid were determined. In the optimization studies for the working conditions, temperature, pH, buffer concentration and species were performed. In the characterization studies of the biosensor; linear range, substrate specificity, interference effect, repeatability, reproducibility and stability experiments were done. According to the results obtained; the optimum amount of enzyme, duration of SAM, AuNP, 3-mercapto propionic acid were found to be 0,5 U/mg, 10 hours, 2 hours and 12 hours. Phosphate buffer (pH:7.0, 50mM) was used and working temperature was determined to be 20 ºC for the biosensor. The linear working range of the biosensor was determined to be 0.1-1.5 µM from the characterization studies. Keywords: biosensor, glycerol-3-phosphate oxidase, gold nanoparticle, glycerol-3-phosphate,