Immobilizing cholesterol oxidase in chitosan-alginic acid network

Yapar, Elif
Kayahan, Senem
Bozkurt, Ayhan
Toppare, Levent Kamil
Proton conducting biopolymer networks have potential use for bio-sensors. The cost-effective, non-hazardous and environmentally safe biopolymer, such as chitosan, is an attractive feature for bio-sensors. Cholesterol oxidase was immobilized in conducting network via complexation of chitosan with alginic acid. A method for the preparation of the complex along with characterization by elemental analysis, FTIR spectroscopy, TGA and DSC were reported. The proton conductivity chitosan-alginic acid network was studied via impedance spectroscopy under humidified condition. The complex polymer electrolyte with x = 1 exhibited maximum proton conductivity of 1.4 x 10(-3) S/cm at RT, RH similar to 50%. The potential use of this network in enzyme immobilization was studied by manufacturing cholesterol oxidase entrapped polymer networks. Additionally, the maximum reaction rate (V-max) and Michaelis-Menten constant (K-m) were investigated for the immobilized cholesterol oxidase. Also, temperature and pH optimization studies were performed, and operational stability and shelf life of the polymer network were examined. (C) 2009 Published by Elsevier Ltd


KUCUKYAVUZ, Z; BAYSAL, BM (Elsevier BV, 1991-01-01)
A method for evaluating the dipole moments of copolymers in relation to the distribution of polar unit sequences is proposed. Experimental data on the synthesis and dipole moments of styrene-p-chlorostyrene and styrene-p-methoxystyrene copolymers were used to calculate the effective dipole moment of a polar unit in a copolymer. For this purpose, we assumed the following effective moment values for the corresponding polar unit sequences along the copolymer chains: when both of the nearest neighbours are pola...
Understanding the influence of hydrogen bonding and diisocyanate symmetry on the morphology and properties of segmented polyurethanes and polyureas: Computational and experimental study
Sami, Selim; Yıldırım, Erol; Yurtsever, Mine; Yurtsever, Ersin; Yilgor, Emel; Yilgor, Iskender; Wilkes, Garth L. (Elsevier BV, 2014-09-02)
Quantum mechanical calculations (QMC) and dissipative particle dynamics (DPD) siniulations were utilized to understand the nature of the short and long-range hydrogen bonding and its influence on the microphase morphology in segmented polyurethanes and segmented polyureas prepared without chain extenders through the stoichiometric reactions of hydroxy or amine terminated poly(tetramethylene oxide) (PTMO-1000) with 1,4-phenylene diisocyanate (PPDI) and 1,3-phenylene diisocyanate (MPDI). The possibility of lo...
AM1 treatment of cyclophanes with vinylic bridges
Türker, Burhan Lemi (Informa UK Limited, 1999-01-01)
Semi-empirical molecular orbital treatment at the level of AM1 type has been performed on the cyclophanes having vinylic bridges. The Hamiltonicity of the cyclophanes is introduced. It has been found that within the isomeric set of these endothermic compounds, the least and the most endothermic ones are Hamiltonian and nonHamiltonian, respectively.
Kinetic study of the reaction between hydroxyl-terminated polybutadiene and isophorone diisocyanate in bulk by quantitative FTIR spectroscopy
Kincal, D; Özkar, Saim (Wiley, 1997-12-05)
A kinetic study of the reaction between a hydroxyl-terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI) was carried out in the bulk state by using quantitative Fourier transform infrared(FTIR) spectroscopy. The reaction is shown to obey a second-order rate law, being first order in both the HTPB and IPDI concentrations. The activation parameters obtained from the evaluation of kinetic data are Delta H-double dagger = 41.1 +/- 0.4 kJ mol, Delta S-double dagger = -198 +/- 2 J K-1 mol(-1) and E-a...
AM1, MNDO and MINDO/3 treatments of Huckel type cyclacenes
Tuerker, Lemi; Guemues, Selcuk (Informa UK Limited, 2006-01-01)
Huckel type cyclacenes having R = 3-10 have been subjected to quantum chemical analyses at the level of AM1, MNDO and MINDO/3 (UHF and RHF) type semi-empirical treatments. The structures have been found to be stable but endothermic in nature. No cryptoannulenic effect has been observed when AM1 (UHF) and MNDO (UHF) treatments are used. Whereas MINDO/3 (UHF) and all the RHF type calculations indicated certain degree of cryptoannulenic effect R = 4 through 8 for the heat of formation values. Frontier molecula...
Citation Formats
E. Yapar, S. Kayahan, A. Bozkurt, and L. K. Toppare, “Immobilizing cholesterol oxidase in chitosan-alginic acid network,” CARBOHYDRATE POLYMERS, pp. 430–436, 2009, Accessed: 00, 2020. [Online]. Available: