Selmiye Alkan

Block copolymers of thiophene-capped Poly(methyl methacrylate) with pyrrole

Poly(methyl methacrylate) with a thiophene end group having narrow polydispersity was prepared by the Atom Transfer Radical Polymerization (ATRP) technique. Subsequently, electrically conducting block copolymers of thiophene-capped poly(methyl methacrylate) with pyrrole were synthesized by using p-toluene sulfonic acid and sodium dodecyl sulfate as the supporting electrolytes via constant potential electrolysis. Characterization of the block copolymers were performed by CV, FTIR, SEM, TGA, and DSC analyses. Electrical conductivities were evaluated by the four-probe technique.

Immobilization of invertase in functionalized copolymer matrices

Abstract In this study, immobilization of invertase on functionalized polymer electrodes constructed with pyrrole-capped polyazotetrahydrofuran and polytetrahydrofuran-block-polystyrene copolymer matrices was performed. Immobilization in these enzyme electrodes was carried out by the entrapment of the enzyme in conducting polymer matrices during electrochemical polymerization of pyrrole. Sodium dodecyl sulphate was used as the supporting electrolyte in the preparation of enzyme electrodes. The effects of temperature and pH on the activity of the enzyme electrodes were examined, and re-use number studies were performed. The changes in the maximum reaction rate and the variations of the Michaelis–Menten constant were investigated.

Immobilization of invertase and glucose oxidase in poly 2-methylbutyl-2-(3-thienyl) acetate/polypyrrole matrices

Abstract Immobilization of invertase and glucose oxidase in conducting polypyrrole and copolymers of poly 2-methylbutyl-2-(3-thienyl) acetate with pyrrole were achieved via electrochemical method. Sodium dodecyl sulphate was found to be the most suitable supporting electrolyte. Maximum reaction rate, Michaelis–Menten constant and optimum temperatures were determined for native and immobilized enzymes. Storage and operational stabilities of enzyme electrodes were also investigated.

Immobilization of invertase in conducting copolymers of 3-methylthienyl methacrylate

Immobilization of invertase in conducting copolymer matrices of 3-methylthienyl methacrylate with pyrrole and thiophene was achieved by constant potential electrolysis using sodium dodecyl sulfate (SDS) as the supporting electrolyte. Polythiophene (PTh) was also used in entrapment process for comparison. Kinetic parameters, Michaelis-Menten constant, K(m), and the maximum reaction rate, V(max), were investigated. Operational stability and temperature optimization of the enzyme electrodes were also examined.

Immobilization of invertase in conducting thiophene-capped poly(methylmethacrylate)/polypyrrole matrices.

Immobilization of invertase in thiophene-capped poly(methylmethacrylate)/polypyrrole matrices was achieved by constant potential electrolysis using different supporting electrolytes. Optimum reaction conditions such as substrate concentration, temperature, and pH for the enzyme electrodes were determined. The temperature and pH were found to be 60 degrees C and 4.8, respectively. The effect of supporting electrolyte on the enzyme activity revealed that SDS was the best in the immobilization procedure. Michaelis-Menten constant and the maximum reaction rate in PMMA/PPy matrices were of the order of that of pristine polypyrrole. However, in terms of repeated use, the copolymer matrices were superior to polypyrrole.

Immobilization of glucose oxidase in polypyrrole/polytetrahydrofuran graft copolymers

Glucose oxidase (GOD) was immobilized in four different conducting polymer matrices, namely: polypyrrole, (PPy), poly(pyrrole-graft-polytetrahydrofuran), (1) and (3); and poly(pyrrole-graft-polystyrene/polytetrahydrofuran), (2). The kinetic parameters V(max) and K(m), and the optimum temperature were determined for both immobilized and native enzymes. The effect of electrolysis time and several supporting electrolytes, p-toluenesulfonic acid, p-toluene sulfonic acid (PTSA), sodium p-toluene sulfonate, sodium p-toluene sulfonate (NaPTS), and sodium dodecyl sulfate, sodium dodecyl sulfate (SDS), on enzyme immobilization were investigated. The high K(m) value (59.9 mM) of enzyme immobilized in PPy was decreased via immobilization in graft copolymer matrices of pyrrole. V(max), which was 2.25 mM/min for pure PPy, was found as 4.71 mM/min for compound (3).

Synthesis and electroactivity of pyrrole end-functionalized poly(2-methyl-2-oxazoline)

Poly(2-methyl-2-oxazoline) (PMeOZO) with pyrrole end groups was synthesized by cationic ring polymerization of 2-methyl-2-oxazoline initiated by benzyl bromide and subsequent modification of the halide end group. The structure and electroactivity of the macromonomer thus obtained were confirmed by spectral analysis and cyclic voltametry, respectively. The posssibility of chemical and electrochemical graft copolymerization of PMeOZO with pyrrole was also studied.

Synthesis and characterization of conducting copolymers of thiophene-3-yl acetic acid cholesteryl ester with pyrrole

A new polythiophene containing a cholesteryl side chain in the β-position was chemically polymerised in nitromethane/carbontetrachloride using FeCl3 as the oxidizing agent. Polymerisation was also achieved by constant current electrolysis in dichloromethane. Subsequently, conducting copolymers of thiophene-3-yl acetic acid cholesteryl ester (CM), PCM1 (obtained from chemical polymerisation method) and PCM4 (obtained from constant current electrolysis) with pyrrole were synthesized using p-toluene sulfonic acid and sodium dodecyl sulfate as the supporting electrolytes via constant potential electrolyses. Characterizations of the samples were performed by CV, FTIR, NMR, DSC, TGA and SEM analyses. Electrical conductivities were measured by the four-probe technique.

Immobilization of urease in conducting thiophene-capped poly(methyl methacrylate)/pyrrole matrices

Urease was immobilized in conducting polypyrrole and block copolymers of thiophene-capped poly(methyl methacrylate) matrices by electropolymerization. Immobilization of the enzyme was achieved by application of 1.0 V constant potential in a solution of 0.02 M pyrrole, 2 mg/ml urease, 0.5 mg/ml supporting electrolyte. The optimum immobilization conditions, electrolysis time, electrolysis medium, enzyme concentration during electrolysis, type of supporting electrolyte were determined. The kinetic behaviors of free and immobilized urease were determined.

IMMOBILIZATION OF YEAST CELLS IN SEVERAL CONDUCTING POLYMER MATRICES

ABSTRACT Immobilization of yeast cells (Saccharomyces cerevisiae) in different polymer matrices was performed by constant potential electrolysis. These matrices were polypyrrole (PPy); poly(methyl methacrylate)/polypyrrole (PMMA/PPy) and thiophene-capped poly(methyl methacrylate)/polypyrrole (TPMMA/PPy). The characterization of PMMA/PPy copolymer was achieved by Fourier-transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM). The invertase activity of immobilized yeast cells was determined. Optimum temperature, Michaelis-Menten constants and maximum reaction rates of the enzyme electrodes were compared with those of free yeast cells. The operational and storage stabilities of three different immobilization systems were analyzed.