Immobilizing cholesterol oxidase in chitosan–alginic acid network

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 × 10−3 S/cm at RT, RH ∼ 50%. The potential use of this network in enzyme immobilization was studied by manufacturing cholesterol oxidase entrapped polymer networks. Additionally, the maximum reaction rate (Vmax) and Michaelis–Menten constant (Km) 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.