Çok Duvarlı Karbon Nanotüpler/Politiyofen Kompozit Kullanılarak Hazırlanan Amperometrik Glikoz Biyosensörü

Bu çalışmada, glikozun amperometrik tespiti için çok duvarlı karbon nanotüpler/politiyofen kompozit (MWCNTs/PTh) modifiye camsı karbon elektrot kullanılmıştır. Glikoz oksidaz (GOx), tiyofenin MWCNT’ler üzerine elektrokimyasal polimerizasyonu ile sentezlenen MWCNT’ler/PTh kompozit film üzerinde çapraz bağlama ajanı tarafından tutulmuştur. Kompozit filmin karakterizasyonu, döngüsel voltametri (CV), fourier dönüşümlü kızılötesi (FTIR) spektroskopisi ve taramalı elektron mikroskobu (SEM) teknikleri ile yapılmıştır. Elektrodun amperometrik ölçümleri, enzimatik olarak üretilen H2O2’nin elektrooksidasyon potansiyeli olan SCE'ye karşı +0.70V’de gerçekleştirilmiştir. Kompozit içindeki tiyofen miktarı, pH, sıcaklık ve substrat derişiminin enzim elektrodunun tepkisi üzerindeki etkileri araştırılmıştır. Oda sıcaklığında optimum pH, 7.0 olarak bulunmuş ve enzim elektrodunun tepkime süresi 25 saniye olarak belirlenmiştir. Lineer çalışma aralığının üst sınırı 4.85 mM glukoz derişimi olarak elde edilmiştir. Sensörün tespit limiti 148 µM olarak hesaplanmıştır. Geliştirilen glukoz biyosensörünün duyarlılığı 4.39 µA mM-1 cm-2 olarak belirlenmiştir. Lineweaver-Burk denklemine göre görünür Michaelis-Menten sabiti (KMapp) değeri 1.68 mM olarak hesaplanmıştır. Bu immobilize enzim sisteminin aktivasyon enerjisi 88.92 kJ mol-1 olarak bulunmuştur.

Anahtar Kelimeler:

Politiyofen, Çok duvarlı karbon nanotüp, Glikoz, Biyosensör, Kompozit

Amperometric Glucose Biosensor Prepared by Using Multi-Walled Carbon Nanotubes/Polythiophene Composite

In this study, multi-walled carbon nanotubes/polythiophene composite (MWCNTs/PTh) modified glassy carbon electrode was used for the amperometric detection of glucose. Glucose oxidase (GOx) was entrapped by a crosslinking agent on the MWCNTs/PTh composite film synthesized by electrochemical polymerization of thiophene onto MWCNTs. Characterization of composite film was achieved by cyclic voltammetry (CV), fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques. The amperometric measurements of electrode was performed at +0.70V vs. SCE, which was the electrooxidation potential of enzymatically produced H2O2. The effects of thiophene amount in the composite, pH, temperature and substrate concentration were investigated on the response of enzyme electrode. Optimum pH was 7.0 at room temperature and the response time of enzyme electrode was 25 s. The upper limit of the linear working range was 4.85 mM glucose concentration. The limit of detection of sensor was calculated as 148 µM. The sensitivity of glucose biosensor was determined as 4.39 µA mM-1 cm-2. The value of apparent Michaelis-Menten constant (KMapp) was 1.68 mM according to the Lineweaver-Burk equation. The activation energy of this immobilized enzyme system was 88.92 kJ mol-1.

Keywords:

Polythiophene, Multi-walled carbon nanotube, Glucose, Biosensor, Composite,

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