A Novel and Effective Surface Design: Conducting Polymer/beta-Cyclodextrin Host-Guest System for Cholesterol Biosensor

The combination of supramolecules and conducting polymers (CPs) has gained much attention for the development of new immobilization matrices for biomolecules. Herein, an amperometric biosensor based on a novel conducting polymer, poly(2-(2-octyldodecyl)-4,7-di(selenoph-2-yl)-2H-benzo[d][1,2,3]triazole)) (PSBTz) and beta-cyclodextrin (beta-CD) for the detection of cholesterol, was constructed. The PSBTz film with beta-CD was deposited on a graphite electrode by electropolymerization technique to achieve a suitable matrix for enzyme immobilization. Moreover, to justify the immobilization, alkyl chain containing conducting polymer (PSBTz) was designed, synthesized and electrochemically polymerized on the transducer surface. Alkyl chains in the structure of SBTz and hydroxyl groups of beta-CD contributed to effective immobilization while protecting the suitable orientation of the biomolecule. Cholesterol oxidase (ChOx) was covalently immobilized onto the modified surface using N,N'-carbonyldiimidazole (CDI) as the cross-linking agent. After successful immobilization, amperometric biosensor responses were recorded at -0.7 V vs Ag/AgCl in phosphate buffer (pH 7.0). The apparent Michaelis-Menten constant (KMapp), maximum current (I-max), limit of detection (LOD), and sensitivity values were determined: 28.9 mu M, 12.1 mu A, 0.005 mu M, and 5.77 mu A/mu M cm(2), respectively. The fabricated biosensor was characterized using scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques. Finally, the prepared biosensor was successfully applied for the determination of cholesterol in blood samples

Selenophene as a Bridge in Molecular Architecture of Benzotriazole Containing Conjugated Copolymers to Gain Insight on Optical and Electrochemical Properties of Polymers

Polymers containing selenophene as a bridge; poly(2-(2-octyldodecyl)-4-(selenophen-2-yl)-7-(5-(thiophen-2-yl)selenophen-2-yl)-2H-benzo[d][1,2,3]triazole)(P1)and poly(2-(2-octyldodecyl)-4-(5-phenylselenophen-2-yl)-7-(selenophen-2-yl)-2H-benzo[d][1,2,3]triazole (P2) were synthesized via Stille and Suzuki coupling reactions, respectively. Optical and electrochemical properties were investigated and comparisons with their thiophene analogs were done. Selenophene substitution resulted in low band gap and red shifted absorption, fast switching times (less than 1s) with reasonable optical contrast. Switching time of P2 was 0.2 second which is the fastest switching time regarding benzotriazole-based polymers. Photovoltaic properties of P1 and P2 were investigated. The optimized devices showed 0.45% and 0.75% power conversion efficiency, respectively

Medium band gap polymer based solution-processed high-kappa composite gate dielectrics for ambipolar OFET

The authors present a novel ambipolar organic filed-effect transistors (OFETs) composed of a hybrid dielectric thin film of Ta2O5: PMMA nanocomposite material, and solution processed poly(selenophene, benzotriazole and dialkoxy substituted [1,2-b: 4, 5-b'] dithiophene (P-SBTBDT)-based organic semiconducting material as the active layer of the device. We find that the Ta2O5: PMMA insulator shows n-type conduction character, and its combination with the p-type P-SBTBDT organic semiconductor leads to an ambipolar OFET device. Top-gated OFETs were fabricated on glass substrate consisting of interdigitated ITO electrodes. P-SBTBDT-based material was spin coated on the interdigitated ITO electrodes. Subsequently, a solution processed Ta2O5: PMMA nanocomposite material was spin coated, thereby creating the gate dielectric layer. Finally, as a gate metal, an aluminum layer was deposited by thermal evaporation. The fabricated OFETs exhibited an ambipolar performance with good air-stability, high field-induced current and relatively high electron and hole mobilities although Ta2O5: PMMA nanocomposite films have slightly higher leakage current compared to the pure Ta2O5 films. Dielectric properties of the devices with different ratios of Ta2O5: PMMA were also investigated. The dielectric constant varied between 3.6 and 5.3 at 100 Hz, depending on the Ta2O5: PMMA ratio

SELENOPHENE AS A BRIDGE IN MOLECULAR ARCHITECTURE OF BENZOTRIAZOLE CONTAINING CONJUGATED COPOLYMERS TO GAIN INSIGHT ON OPTICAL AND ELECTROCHEMICAL PROPERTIES OF POLYMERS

Polymers containing selenophene as a bridge; poly(2-(2-octyldodecyl)-4-(selenophen-2-yl)-7-(5-(thiophen-2-yl)selenophen-2-yl)-2H-benzo[d][1,2,3]triazole)(P1)and poly(2-(2-octyldodecyl)-4-(5-phenylselenophen-2-yl)-7-(selenophen-2-yl)-2H-benzo[d][1,2,3]triazole (P2) were synthesized via Stille and Suzuki coupling reactions, respectively. Optical and electrochemical properties were investigated and comparisons with their thiophene analogs were done. Selenophene substitution resulted in low band gap and red shifted absorption, fast switching times (less than 1s) with reasonable optical contrast. Switching time of P2 was 0.2 second which is the fastest switching time regarding benzotriazole-based polymers. Photovoltaic properties of P1 and P2 were investigated. The optimized devices showed 0.45% and 0.75% power conversion efficiency, respectively

Benzotriazole and Benzodithiophene Containing Medium Band Gap Polymer for Bulk Heterojunction Polymer Solar Cell Applications

An alternating donor-acceptor copolymer based on a benzotriazole and benzodithiophene was synthesized and selenophene was incorporated as -bridge. The photovoltaic and optical properties of polymer were studied. The copolymer showed medium band gap and dual absorption peaks in UV-Vis absorption spectra. Photovoltaic properties of P-SBTBDT were performed by conventional device structure. The OSC device based on polymer: PC71BM (1:1, w/w) exhibited the best PCE of 3.60% with a V-oc of 0.67 V, a J(sc) of 8.95 mA/cm(2), and a FF of 60%. This finding was supported with morphological data and space charge limited current (SCLC) mobilities. The hole mobility of the copolymer was estimated through SCLC model. Although surface roughness of the active layer is really high, mobility of a polymer was found as 7.46 x 10(-3) cm(2)/Vs for optimized device that can be attributed to Se-Se interactions due to the larger, more-polarizable Se atom. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 528-53

A novel architecture based on a conducting polymer and calixarene derivative: its synthesis and biosensor construction

In this study, a novel amperometric glucose biosensor based on a selenium comprising conducting polymer and calixarene was developed. Firstly, poly(2-(2-octyldodecyl)-4,7-di(selenoph-2-yl)-2H-benzo[d][1,2,3]-triazole), poly((SBTz)) was electrodeposited onto a graphite electrode by an electropolymerization technique. Then, a newly synthesized calixarene and gold nanoparticle (AuNP) mixture was used for the improvement of biosensor characteristics. GOx, as a model enzyme was immobilized on the modified electrode surface. The constructed surface serves as a sufficient immobilization platform for the detection of glucose. Calixarenes and their derivatives may be a favouring agent for enzyme immobilization due to their specific configurations. Moreover, through the covalent binding between the carboxylic groups of the calixarenes and amino groups of the biomolecule, effective enzyme immobilization can be achieved while protecting the well-ordered structure of the enzyme molecule. Amperometric detection was carried out following oxygen consumption at -0.7 V vs. the Ag reference electrode in phosphate buffer (50 mM, pH 6.5). The proposed biosensor showed a linear amperometric response for glucose within a concentration range of 0.005 to 0.5 mM (LOD: 0.004 mM). K-m(app) and sensitivity were calculated as 0.025 mM and 102 mu A mM(-1) cm(-2), respectively. Scanning Electron Microscopy (SEM) was used to investigate the surface morphologies of successive modifications. Finally, the constructed biosensor was tested successfully to detect glucose in beverage samples

High stability of benzotriazole and benzodithiophene containing medium band-gap polymer solar cell

The improvement of polymer solar cell stability is a challenge for the scientists and has significant implications commercially. In this study, we investigated the stability of a novel P-SBTBDT active material applied in an inverted type solar cell. Detailed stability experiments comprising shelf life, laboratory weathering and outdoor testing were carried out according to ISOS testing guidelines. Shelf life showed that P-SBTBDT solar cells were very stable after 840 h with encapsulation. Although accelerated weathering aging tests are a very harsh, the devices remained stable after the bum-in phase with T-50 from 700 to 840 h, with some P-SBTBDT solar cells did not reach T-50 in the time span of the test. Degradation tests on the P-SBTBDT solar cells which were carried out under natural solar light indicated that T-40 was reached after 840 h. The results of dark, light, damp and dry stability tests showed that most of the degradation was provoked by failure of the encapsulation. The experiments indicated that P-SBTBDT solar cells are sensitive to light and oxygen but are strikingly stable under humid conditions. Further developments for minimizing the degradation effects using UV-filters and better encapsulation are some of the necessary improvements in further research

A Novel and Effective Surface Design: Conducting Polymer/β-Cyclodextrin Host–Guest System for Cholesterol Biosensor

The combination of supramolecules and conducting polymers (CPs) has gained much attention for the development of new immobilization matrices for biomolecules. Herein, an amperometric biosensor based on a novel conducting polymer, poly(2-(2-octyldodecyl)-4,7-di(selenoph-2-yl)-2H-benzo[d][1,2,3]triazole)) (PSBTz) and beta-cyclodextrin (beta-CD) for the detection of cholesterol, was constructed. The PSBTz film with beta-CD was deposited on a graphite electrode by electropolymerization technique to achieve a suitable matrix for enzyme immobilization. Moreover, to justify the immobilization, alkyl chain containing conducting polymer (PSBTz) was designed, synthesized and electrochemically polymerized on the transducer surface. Alkyl chains in the structure of SBTz and hydroxyl groups of beta-CD contributed to effective immobilization while protecting the suitable orientation of the biomolecule. Cholesterol oxidase (ChOx) was covalently immobilized onto the modified surface using N,N'-carbonyldiimidazole (CDI) as the cross-linking agent. After successful immobilization, amperometric biosensor responses were recorded at -0.7 V vs Ag/AgCl in phosphate buffer (pH 7.0). The apparent Michaelis-Menten constant (KMapp), maximum current (I-max), limit of detection (LOD), and sensitivity values were determined: 28.9 mu M, 12.1 mu A, 0.005 mu M, and 5.77 mu A/mu M cm(2), respectively. The fabricated biosensor was characterized using scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques. Finally, the prepared biosensor was successfully applied for the determination of cholesterol in blood samples