A disposable biosensor for urea determination in blood based on an ammonium-sensitive transducer

• Published in: Biosensors & bioelectronics Vol. 14; no. 1; pp. 33 - 41
• Main Authors: Eggenstein, Claudia, Borchardt, Michael, Diekmann, Christoph, Bernd Gründig, Dumschat, Christa, Cammann, Karl, Knoll, Meinhard, Friedrich Spener
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 1999; Elsevier Science
• Subjects: Biological and medical sciences; Biosensing Techniques; Biosensors; Biotechnology; Blood; Blood urea; Disposable biosensor; Disposable reference electrode; Electrochemical electrodes; Enzyme immobilization; Fundamental and applied biological sciences. Psychology; Humans; Hydrogels; Membranes, Artificial; Methods. Procedures. Technologies; Nitrogen compounds; Polymeric membranes; Polyurethanes; Potentiometric biosensor; Potentiometric sensors; Potentiometry; Quaternary Ammonium Compounds; Transducers; Urea; Urea - blood; Urea biosensor; Various methods and equipments; Urea biosensor; Disposable reference electrode; Potentiometric biosensor; Disposable biosensor; Blood urea; Performance evaluation; Disposable; Enzyme; Urease; Potentiometry; Enzyme electrode; Blood; Ion selective electrode; Urea; Biosensor; Hydrolases; Immobilized enzyme; Medical application; Quantitative analysis
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/S0956-5663(98)00103-1

A potentiometric urea-sensitive biosensor using a NH + 4-sensitive disposable electrode in double matrix membrane (DMM) technology as transducer is described. The ion-sensitive polymer matrix membrane was formed in the presence of an additional electrochemical inert filter paper matrix to improve the reproducibility in sensor production. The electrodes were prepared from one-side silver-coated filter paper, which is encapsulated for insulation by a heat-sealing film. A defined volume of the NH + 4-sensitive polymer matrix membrane cocktail was deposited on this filter paper. To obtain the urea-biosensor a layer of urease was cast onto the ion-sensitive membrane. Poly (carbamoylsulfonate) hydrogel, produced from a hydrophilic polyurethane prepolymer blocked with bisulfite, served as immobilisation material. The disposable urea-sensitive electrode was combined with a disposable Ag/AgCl reference electrode to obtain the disposable urea biosensor. The sensor responded rapidly and in a stable manner to changes in urea concentrations between 7.2×10 −5 and 2.1×10 −2 mol/l. The detection limit was 2×10 −5 mol/l urea and the slope in the linear range 52 mV/decade. By taking into consideration the influence of the interfering K +- and Na +- ions the sensor can be used for the determination of urea in human blood and serum samples (diluted or undiluted). A good correlation was found with the data obtained by the spectrophotometric routine method.