Electrochemical biosensors for glucose, lactate, urea, and creatinine based on enzymes entrapped in a cubic liquid crystalline phase

• Published in: Analytica chimica acta Vol. 289; no. 2; pp. 155 - 162
• Main Authors: Razumas, Valdemaras, Kanapieniené, Julija, Nylander, Tommy, Engström, Sven, Larsson, Kåre
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 29.04.1994; Elsevier
• Subjects: Amperometry; Biological and medical sciences; Biosensors; Biotechnology; Creatinine; Cubic phase; Entrapment; Enzyme electrodes; Fundamental and applied biological sciences. Psychology; Glucose; Lactate; Methods. Procedures. Technologies; Monoolein; Potentiometry; Urea; Various methods and equipments; Enzyme electrodes; Creatinine; Urea; Entrapment; Lactate; Monoolein; Amperometry; Glucose; Potentiometry; Biosensors; Cubic phase; Encapsulation; Lactates; Cubic crystals; Biosensor; Lipids; Enzyme electrode; Quantitative analysis
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/0003-2670(94)80098-7

A novel method to construct enzyme-based biosensors, where the enzyme is entrapped in a lipid matrix (cubic liquid crystalline phase) is presented. The cubic phases were made of monoolein (1-monooleyl-glycerol) and 35% (w/w) of water-based enzyme solutions. The biocatalytic layers of the sensors consisted of a thin layer of the cubic phase with entrapped enzyme, which was coated with a dialysis membrane. The idea was used to construct and investigate the performance of amperometric β- d-glucose and l-lactate, and pH-sensitive urea and creatinine bioelectrodes based on glucose oxidase, lactate oxidase, urease, and creatinine deiminase. The amperometric enzyme electrodes generate an anodic biocatalytic current due to the oxidation of H 2O 2 at the Pt electrode. Using the urease- and creatinine deiminase-based pH electrodes, proton consumption in the enzymatic reactions is measured. The data for the amperometric sensors are presented on the influence of substrate concentration, potential, pH, and temperature upon the electrodes, Urease- and creatinine deiminase-pH electrodes are tested in relation to the substrate and enzyme concentration, and the buffer capacity. Results of the electrodes long-term stability are discussed in relation to the structural features of the cubic phase and the enzyme.