Electrochemical and optical properties of a conducting polymer and its use in a novel biosensor for the detection of cholesterol

Kesik, Melis
ERGÜN, Mustafa Yavuz
Toppare, Levent Kamil
A simple and robust cholesterol biosensor was designed by immobilizing cholesterol oxidase (ChOx) onto a conducting polymer modified graphite electrode. For this purpose, monomer, (Z)-4-(4-(9H-carbazol-9-yl) benzylidene) 2 (4 nitrophenyl) oxazol-5(4H)-one (CBNP), was synthesized and electrochemically polymerized on an electrode to achieve an effective immobilization platform for enzyme immobilization. After electropolymerization of the monomer (CBNP), electrochemical and spectroelectrochemical properties were investigated. Through the presence of nitro group on the polymer backbone hydrogen-bonding between enzyme molecules and polymer was achieved. Moreover, strong pi-pi stacking between aromatic moities in the polymer and aromatic residues of the enzyme enables a sensitive and reliable biosensor by conserving the crucial structure of biological molecules during the enzymatic reaction. The efficient interaction of the enzyme with the polymer coated surface brings easy and long-life detection of the substrate, cholesterol. After successful immobilization of ChOx with the help of glutaraldehyde as the crosslinking agent, amperometric biosensor responses were recorded at -0.7 V vs Ag wire in phosphate buffer (pH 7.0). K-M(app) (37.3 mu M), I-max (3.92 mu A), LOD (0.4063 mu M) and sensitivity (1.49 pA mu M-1 cm(-2)) values were determined. Finally, the prepared biosensor was successfully applied for determination of cholesterol content in real blood samples.


Selenium containing conducting polymer based pyranose oxidase biosensor for glucose detection
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A novel amperometric pyranose oxidase (PyOx) biosensor based on a selenium containing conducting polymer has been developed for the glucose detection. For this purpose, a conducting polymer; poly(4,7-bis(thieno[3,2-b]thiophen-2-yl)benzo[c][1,2,5] selenadiazole) (poly(BSeTT)) was synthesized via electropolymerisation on gold electrode to examine its matrix property for glucose detection. For this purpose, PyOx was used as the model enzyme and immobilised via physical adsorption technique. Amperometric detect...
Electrochemical polymerization of 1-(4-nitrophenyl)-2,5-di(2-thienyl)-1 H-pyrrole as a novel immobilization platform for microbial sensing
Tuncagil, Sevinc; ODACI DEMİRKOL, DİLEK; Varis, Serhat; TİMUR, SUNA; Toppare, Levent Kamil (2009-09-01)
Two types of bacterial biosensor were constructed by immobilization of Gluconobacter oxydans and Pseudomonas fluorescens cells on graphite electrodes modified with the conducting polymer; poly(1-(4-nitrophenyl)-2,5-di(2-thienyl)-1 H-pyrrole) [SNS(NO2)]. The measurement was based on the respiratory activity of cells estimated by the oxygen consumption at -0.7 V due to the metabolic activity in the presence of substrate. As well as analytical characterization, the linear detection ranges, effects of electropo...
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SÖYLEMEZ, SANİYE; Kanik, Fulya Ekiz; Ileri, Merve; Hacioglu, Serife O.; Toppare, Levent Kamil (2014-01-15)
A new type of amperometric cholesterol biosensor was fabricated to improve the biosensor characteristics such as sensitivity and reliability. For this purpose, a novel immobilization matrix 2-(4-fluorophenyl)-4,7-di(thiophene-2-yl)-1H-benzo[d]imidazole (BIPF) was electrochemically deposited on a graphite electrode and used as a matrix for the immobilization of cholesterol oxidase (ChOx). Due to strong pi-pi stacking of aromatic groups in the structures of polymer backbone and enzyme molecule, one can easily...
Design of Carbon Nanotube Modified Conducting Polymer for Biosensing Applications
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An electrochemical biosensor with improved performance was designed through the immobilization of glucose oxidase (GOx) onto conducting polymer of 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine (SNS-NH2) modified with carbon nanotubes (CNTs). For the optimization and characterization of the biosensor, pH profile, enzyme loading, reproducibility, operational stability experiments were carried out. It was found that the use of CNTs in a biosensing system enhanced the biosensor response. The linear relati...
Fabrication of a promising immobilization platform based on electrochemical synthesis of a conjugated polymer
Buber, Ece; SÖYLEMEZ, SANİYE; UDUM, YASEMİN; Toppare, Levent Kamil (2018-07-01)
Since conjugated polymers are an important class of materials with remarkable properties in biosensor applications, in this study, a novel glucose biosensor based on a conjugated polymer was fabricated via the electropolymerization of the monomer 10,13-bis(4-hexylthiophen-2-yl)dipyridol[3,2-a:2',3'-c]phenazine onto a graphite electrode surface. Glucose oxidase (GOx) was used as the model biological recognition element. As a result of the enzymatic reaction between GOx and glucose, the glucose amount was det...
Citation Formats
S. SÖYLEMEZ, Y. UDUM, M. Kesik, C. G. HIZLIATEŞ, M. Y. ERGÜN, and L. K. Toppare, “Electrochemical and optical properties of a conducting polymer and its use in a novel biosensor for the detection of cholesterol,” SENSORS AND ACTUATORS B-CHEMICAL, pp. 425–433, 2015, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/47101.