Colloids and Surfaces B: Biointerfaces 167 (2018) 392–396 Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces jo ur nal ho me p ag e: www.elsevier.com/locate/colsurfb Fabrication of a promising immobilization platform based on electrochemical synthesis of a conjugated polymer Ece Buber a , Saniye Soylemez b,∗ , Yasemin A. Udum c , Levent Toppare a,d,e,f,∗∗ a Department of Chemistry, Middle East Technical University, Ankara 06800, Turkey b Department of Chemistry, Ordu University, Ordu 52200, Turkey c Technical Sciences Vocational School, Gazi University, Ankara 06374, Turkey d Department of Biotechnology, Middle East Technical University, Ankara 06800, Turkey e Department of Polymer Science and Technology, Middle East Technical University, Ankara 06800, Turkey f The Center for Solar Energy Research and Application (GUNAM), Middle East Technical University, Ankara 06800, Turkey a r t i c l e i n f o Article history: Received 8 February 2018 Received in revised form 18 April 2018 Accepted 20 April 2018 Available online 22 April 2018 Keywords: Amperometric biosensor Conjugated polymer Electropolymerization Glucose biosensor a b s t r a c t 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 determined by monitoring the change in the oxygen level associated with substrate concentration via the amperometric detection technique. The proposed system possessed superior properties with K M app value of 0.262 mM, 2.88 × 10 −3 mM limit of detection and 105.12 A mM −1 cm −2 sensitivity. These results show that conjugated polymer film provides an effective and stable immobilization matrix for the enzyme. Finally, the biosensor was applied successfully to several commercially available beverage samples for glucose determination proving an inexpensive and highly sensitive system applicable for real time analyses. © 2018 Elsevier B.V. All rights reserved. 1. Introduction Development of analytical devices for the estimation and mon- itoring of biological samples have become the major interest in biotechnology and have been accelerated since it has been real- ized that biological systems can offer a commercial potential [1]. The biggest challenge in this area is the convertion of the biological data to a measurable signal since it is a complex issue to connect an electronic system to a biological environment. For this purpose, electrochemical biosensors are attractive devices to analze biologi- cal samples providing direct conversion of a biological event into an electrical signal [2]. Diabetes mellitus is the most common endocrine disorder related with the carbohydrate metabolism and it is char- acterized by abnormal level of blood glucose concentrations [3]. ∗ Corresponding author at: Ordu University, Department of Chemistry, 52200, Ordu, Turkey. ∗∗ Corresponding author at: Middle East Technical University, Department of Chemistry, 06800, Ankara, Turkey. E-mail addresses: saniyesoylemez@odu.edu.tr (S. Soylemez), toppare@metu.edu.tr (L. Toppare). Moreover glucose is one of the most critical biological compounds for life among all the others found in nature since it is responsible for energy generation for growth and reproduction processes [4]. As a result, it is important to determine the glucose level quantita- tively and continuously. Although there are a number of different methods for glucose detection such as liquid chromatography [5] and spectrometric techniques [6], these methods require skilled personnel, complicated sample preparation and have the limita- tion to be miniaturized. Considering these disadvantages, intense attraction has been shifted to the development of biosensors since they possess extensive sensitivity and specificity and have simple, easy-to-use formats [7,8]. Among the different types of biosen- sors, electrochemical methods, especially amperometric one, has become the most widely used technique in glucose sensing [9]. The principle of working of amperometric biosensors is the measure- ment of the current produced due to the reduction or oxidation of the electroactive species in the medium upon application of a constant potential [10–12]. In order to provide a suitable matrix for biomolecules where they can sustain their activity, it is essential to design a proper surface for the biosensor. Conjugated polymers (CPs) are one of https://doi.org/10.1016/j.colsurfb.2018.04.041 0927-7765/© 2018 Elsevier B.V. All rights reserved.